INTRODUCTION
The 27th Conference of the Parties (COP27) to the United Nations Framework Convention on Climate Change (UNFCCC) was held in Sharm El-Sheikh, Egypt from November 6 to November 20, 2022.[] At a critical moment for achieving green recovery on a global scale, the conference reiterated the goals set at the COP21, which aim to limit the global temperature increase to within 1.5°C to address the urgent issue of global environmental change.[] Looking back at the COP26 held in Glasgow in 2021, countries that account for 55% of global greenhouse gas emissions submitted strengthened emissions reduction targets for 2030 to the COP26, while countries that account for 32% of global greenhouse gas emissions submitted long-term low greenhouse gas emission development strategies for the mid-century.[] With world leaders, government representatives, businesses, and citizens paying attention to the COP, climate change has evolved from a marginal issue to a global priority, and there are high expectations for new commitments to reducing carbon emissions from countries.[]
According to the report of the International Energy Agency (IEA), transportation is a key area for carbon emissions. In 2021, greenhouse gas emissions from transportation accounted for approximately one-fourth of global energy consumption carbon emissions, with road transportation accounting for 76.1% of total transportation emissions.[] Therefore, countries and regions around the world are actively promoting the electrification of the transportation sector. Reducing carbon emissions by developing zero-emission cars, buses, and trucks is also an important way to combat global warming.[] The 26th United Nations Climate Change (COP26) also made it clear that countries need to reach a consensus to quickly phase out the most polluting fossil fuels such as coal while developing electric vehicles (EVs) to replace fuel-based transportation with electric transportation as soon as possible to reduce carbon emissions.[]
After more than a decade of rapid development, the global stock of EVs reached 10 million by the end of 2020 and is still growing rapidly.[] However, concerns about whether EVs can reduce carbon emissions from the transportation sector are increasing as global warming remains uncontrolled within 1.5°C. Therefore, many studies have explored the lifecycle carbon emissions of EVs and compared them with those of traditional internal combustion engine vehicles (ICEVs).[] Some studies have shown that batteries, as the core component of EVs, have a significant impact on their carbon emissions.[] Specifically, the high energy consumption and emissions during battery production make EVs have higher carbon emissions in the production stage than traditional ICEVs.[] In the vehicle usage stage, the carbon emissions of EVs depend largely on the cleanliness of the electricity.[] If EVs are charged with clean energy sources such as wind and solar power, their carbon emissions will be significantly lower than those of ICEVs; When charged with coal-fired electricity, the carbon emissions of EVs may be higher than those of ICEVs.[] In addition, appropriate recycling of used batteries can reduce the lifecycle carbon emissions of EVs. Based on these studies, scholars have further explored the carbon footprint of batteries from different perspectives. In terms of the lifecycle, the battery production stage, particularly the material preparation stage, is the main contributor to lifecycle carbon emissions.[] If the impact of manufacturing location is considered, the carbon emissions of LMO/graphite batteries and LFP/graphite batteries produced in China are higher than those in Europe, which is also related to the cleanliness of local electricity.[] Finally, the working temperature, current rate, and average state of charge during cycles also affect the lifespan of lithium-ion batteries (LIBs), thereby having a significant impact on their carbon footprint.[]
In summary, countries around the world are actively promoting the electrification of road transportation to alleviate the problem of carbon emissions from the transportation sector. However, the widespread adoption of EVs has not resulted in the expected environmental benefits. To improve the low-carbon characteristics of EVs, many studies have analyzed the lifecycle carbon footprint of EVs, as well as the lifecycle carbon footprint of key components, such as power batteries. While the focus of these studies varies, few have provided a comprehensive overview of the literature. Therefore, we attempt to summarize existing research articles, providing a systematic explanation of the lifecycle carbon footprint of EVs, and discuss the potential for the automotive industry to further reduce carbon emissions by considering the full lifecycle management of onboard power batteries.
In the first section of this review, we provide a systematic introduction to the methods and standards of carbon accounting and further illustrate the main topics of carbon accounting in the automotive industry. We also analyze the process of calculating the carbon footprint of a vehicle's entire lifecycle. In the second section, we analyze the carbon emissions from road transportation and emphasize the importance of reducing emissions from automobiles for global carbon neutrality. Through a comparison of the carbon footprints of ICEVs and EVs throughout their lifecycles, we point out the necessity of electrification in achieving carbon neutrality goals, while also acknowledging that EVs still have carbon emissions issues. In the third section, we summarize the carbon neutrality goals of various automobile companies and analyze the decarbonization measures and their effectiveness in the automotive industry value chain. These measures further reduce carbon emissions from the cradle-to-gate stage (from the extraction of raw materials to the point of leaving the manufacturing facility) and lower the carbon footprint of vehicles throughout their lifecycles. In the fourth section, we focus on the carbon footprint of the entire lifecycle of onboard power batteries and elaborate on how to reduce the carbon footprint of batteries by strengthening lifecycle management, thereby reducing the overall carbon footprint of EVs. Our review not only provides a reference for subsequent research on carbon emissions from EVs but also summarizes the potential measures for further decarbonization of EVs. This is important for promoting the adoption of EVs, mitigating carbon emissions from the transportation sector, and achieving carbon neutrality goals.
METHODOLOGY FOR CARBON EMISSION ACCOUNTING
Accurate carbon emission accounting is the foundation of emission reduction. In the context of carbon neutrality, the low-carbon transformation of the automotive industry is imperative. It is of great significance to establish a scientific and sound carbon accounting system, which clarifies the theoretical basis and standard for carbon emissions accounting that applies to the automotive industry, for the carbon management of the automotive industry and its entire value chain, and to achieve effective carbon reduction. At the same time, by hierarchically refining the carbon accounting objects at various levels of the automotive industry, clarifying their accounting methods and their scope of application, it is beneficial to the automotive industry to rationally allocate emission reduction targets at various stages and achieve carbon neutrality as soon as possible across the industry.
Carbon footprint accounting
Currently, the methods for calculating carbon footprints mainly include input-output (I-O) analysis and life cycle assessment (LCA).[] The I-O analysis calculates the greenhouse gas emissions of each sector resulting from the production of products or services by compiling input-output tables and establishing appropriate mathematical balance equations.[] Essentially, the I-O analysis is a top-down comprehensive calculation method, which is more suitable for carbon footprint calculation at the macro level (such as national, sectoral, and corporate levels). LCA analyzes all inputs and outputs of a product, service, process, or event throughout its entire lifecycle to discuss its environmental impact.[] Compared with the I-O method, LCA is a bottom-up calculation method that is more suitable for calculating carbon footprints at the micro level (specific products or services) due to its detailed and accurate calculation process.
In addition to accounting methods, selecting appropriate accounting standards is equally important. When calculating carbon footprints, different carbon accounting standards often apply to different accounting levels. Currently, the Intergovernmental Panel on Climate Change (IPCC), the International Organization for Standardization (ISO), the World Resources Institute (WRI), and the World Business Council for Sustainable Development (WBCSD) have all issued relevant carbon emission quantification accounting standards or technical specifications. As shown in Table , the published carbon accounting standards can be divided into five categories according to the different accounting objects: country/region, city, enterprise/organization, product/service, and project. Among them, carbon emissions at the country/region and city levels refer to the carbon emissions generated by the consumption of total materials and energy within a designated area, such as a country, community, or city. For the last three accounting objects, namely enterprise/organization level, product/service level, and project level accounting, their statistics of carbon emissions are often highly related to the carbon footprint of a specific product, which includes all carbon emissions generated during the manufacturing, usage, and disposal of a certain product or service. Among them, the widely used accounting standard system at the enterprise/organization level is the Greenhouse Gas Protocol (The GHG Protocol)[] and the ISO system, which are internationally recognized tools for calculating greenhouse gas emissions. The latter also provides widely recognized basic standards for calculating greenhouse gas emissions at the product/service level, which are used by many institutions and companies for assessing environmental risks of suppliers.
Table 1 Carbon accounting objects and their standards.
| Accounting objects | Standard names | Issuer |
| Country/Region | 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories | IPCC |
| City | Global Protocol for Community-Scale Greenhouse Gas Emission Inventories | WRI, C40, ICLEI |
| Enterprise/Organization | The Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard | WBCSD, WRI |
| ISO 14064-1:2018 | ISO/TC207/SC7 | |
| Product/Service | Greenhouse Gas Protocol Product Life Cycle Accounting and Reporting Standard | WBCSD, WRI |
| ISO 14067:2018 | ISO/TC207/SC7 | |
| Project | The GHG Protocol for Project Accounting | WBCSD, WRI |
| ISO 14064-2:2019 | ISO/TC207/SC7 |
It is worth noting that at the product/service level, the main accounting method, “Product Life Cycle Assessment and Reporting,”[] covers the greenhouse gas emissions and removals throughout the entire lifecycle of the product. It mainly includes three different scopes of greenhouse gas emissions: Scope 1, the greenhouse gas emissions directly controlled by the enterprise from combustion processes and physical and chemical production processes (i.e., direct emissions); Scope 2, the greenhouse gas emissions from the energy sources purchased outside the enterprise, such as electricity, heat, steam, and cooling (i.e., indirect emissions); and Scope 3, the emissions covering the entire value chain of the enterprise (i.e., indirect emissions from upstream and downstream activities in the value chain). Additionally, another accounting standard at this level, the ISO 14067 standard, establishes a carbon emissions evaluation system based on a full LCA, environmental labeling, and declaration. This system enables the quantification of the carbon footprint of a product and its communication with the outside world.
Accounting for carbon emissions in the automotive industry
To analyze the carbon footprint of the automotive industry, it is necessary to understand the relevant carbon accounting standards. For the automotive industry, carbon accounting specifically involves both enterprise/organization level and product/service level carbon accounting, and in some specific issues, partially involves project level carbon accounting. Depending on the specific objects of the automotive industry, carbon emissions accounting in the automotive industry can be roughly divided into five categories: carbon emissions from vehicle manufacturers, product lifecycle, vehicle R&D projects, related services, and events. The specific accounting scope involved in each carbon accounting category is shown in Table .
Table 2 Carbon emissions accounting scope in the automotive industry.
| Accounting objects | Accounting scope | Source of carbon emissions |
| Automobile enterprise/organization level | Scope 1 | Direct emissions within automobile enterprises, including fossil fuel combustion emissions, enterprise production process emissions/special emissions, and deducted emissions |
| Scope 2 | Internal direct emissions of automobile enterprises and implicit emissions of electricity and heat or steam or cold air purchased by enterprises | |
| Automobile product level (Full-vehicle/parts) | Lifecycle | Direct and indirect emissions during the whole life cycle of automotive products, including the use of whole vehicles, assembly of whole vehicles, production of parts, production of raw materials, transportation, recycling, and other processes |
| Automobile project level | Implementation cycle | Emission reduction compared with the baseline scenario after project implementation |
| Automobile service level | Service cycle | Fossil energy and purchased power consumed by service-related equipment and vehicles |
| Large event level | Event cycle | Fossil fuel combustion emissions, net purchased electricity/heat emissions, transportation emissions, accommodation and catering emissions, implicit carbon emissions from conference supplies, and emissions from waste disposal related to fixed and mobile sources throughout the event |
Among all carbon accounting scopes, the most attention has been given to the carbon accounting of automobile companies and their products.[] There are two main types of carbon emissions accounting scopes for the automobile industry. The first is the direct carbon emissions (Scope 1) generated by the operation of the automobile companies themselves, including emissions from the combustion of fossil fuels, process emissions/special emissions during production, and emissions that are deducted due to the recovery and utilization of CO2 and CH4. The second type, in addition to the direct emissions in Scope 1, also includes implicit emissions such as electricity and heat that are net purchased by automobile companies (Scope 2). The carbon emissions accounting conducted by automobile companies can help them manage greenhouse gas, identify emission reduction opportunities, and support participation in voluntary greenhouse gas reduction programs and carbon emissions trading.[] In the practice of carbon emissions accounting at the enterprise/organization level, Ford Motor Company established a cross-departmental greenhouse gas emissions team a greenhouse gas emissions inventory based on enterprise standards in accordance with the greenhouse gas accounting system.[] The inventory includes direct emissions from emission sources owned or controlled by the company, as well as indirect emissions from the purchase of electricity, heat or steam during the production process. The scope of greenhouse gas reporting has been expanded to include all of its global brands. Several researchers have conducted studies on the carbon emissions of enterprise/organization.[] Poschmann et al.[] conducted carbon accounting for the automotive industry from each accounting object and analyzed the differences between the automotive corporate climate targets and global climate targets.
Carbon emissions accounting at the product level of automobiles refers to the carbon emissions related to the whole vehicle or automotive components, which covers direct and indirect emissions throughout the lifecycle of the automobile products, including vehicle usage, vehicle assembly, component production, raw material production, logistics, and recycling. For example, previous studies have investigated the life-cycle carbon emissions of ICEV components, such as ignition coil,[] fuel tank,[] and body steel.[] Using the CA-GREET Model, Woertz et al.[] conducted a study on the life-cycle carbon emissions of fuels in the usage of ICEVs. For EVs, especially BEVs, researchers are focusing on carbon emissions over the life-cycle of the power batteries.[] The vehicle manufacturing process also generates objective carbon emissions, and Javadi et al.[] and Tan et al.[] investigated the carbon emissions of the manufacturing process in Iran and Chongqing, China, respectively. Accounting and reporting the carbon emissions of automobile products can help automobile companies grasp the greenhouse gas emissions of the lifecycle of automobile products and better guide the development of low-carbon technologies for automobile companies.
It is important to recognize that there is an overlap in the calculation of carbon footprints between the product and enterprise levels of the automotive industry. As a result, the full lifecycle carbon accounting of automotive products will include both direct and indirect carbon emissions from automotive manufacturers. Therefore, before conducting a full lifecycle carbon footprint analysis of automotive products, it is necessary to determine the boundaries of carbon emissions accounting, including the accounting entity, accounting scope, and accounting period. From the perspective of the accounting entity, the carbon emissions accounting of automotive products will involve the accounting of carbon emissions from the automotive enterprise itself, as well as from the upstream and downstream value chain. At the same time, the accounting implementation entity will also include automotive resource utilization enterprises such as recycling and dismantling companies, auto parts remanufacturing companies, power battery echelon utilization enterprises, and recycling enterprises. When evaluating the carbon emissions of the lifecycle of automobiles, it can generally be divided into three parts: the fuel period, the parts period, and the vehicle period, as shown in Figure . The fuel period includes the carbon footprint involved in the entire process from crude oil extraction, refining, to the final production of petroleum products. The parts period refers to the carbon footprint of various assembly systems and components for the vehicle. And the vehicle period can be further divided into three parts: vehicle assembly, vehicle usage, maintenance, dismantling, and recycling. The carbon emissions from the consumption of electricity used in the production and operation of the three periods should also be taken into account. For EVs, their carbon footprint mainly comes from the consumption of electricity during vehicle usage. Finally, the expected lifecycle of the automotive product is determined as the accounting period, usually measured in terms of mileage or years of usage. After the boundaries of automotive carbon emissions accounting are established, a carbon emissions accounting data list can be compiled, and the carbon emissions of each item in the list can be calculated one by one. Through the lifecycle carbon footprint accounting of automotive products, the environmental impact of different energy types of vehicles can be compared in detail, providing theoretical and data support for subsequent emissions reduction efforts in the automotive industry.
[IMAGE OMITTED. SEE PDF]
ROAD TRANSPORTATION CARBON EMISSIONS
Carbon emissions from the transportation sector
Road transportation is an important component of the transportation sector, and carbon reduction in road transportation is the key to achieving carbon neutrality in the transportation sector. By surveying the overall carbon emissions in the transportation sector, the significance of carbon reduction in road transportation can be realized in a comprehensive way, as well as the major challenges it faces. This can help clarify the direction of breakthroughs in carbon reduction technologies for the automobile and identify the main bottlenecks that need to be addressed.[]
As one of the major sources of global carbon emissions, reducing carbon emissions in the transportation sector is crucial for achieving carbon neutrality worldwide. According to the 2022 report by the IEA, greenhouse gas emissions from transportation activities in 2021 accounted for about 25% of global energy consumption carbon emissions, exceeding all energy-related carbon emissions in North America.[] A similar situation can be observed in China. As one of the fastest-growing sectors in terms of carbon emissions in China, the energy consumption of the transportation sector reached nearly 500 million tons of standard coal in 2019, accounting for approximately 11% of the total energy consumption. And the related carbon dioxide emissions exceeded 900 million tons, accounting for about 10% of the national energy-related carbon emissions.[] However, in the following years, due to the lockdowns in major cities by COVID-19 measures and the popularity of EVs, China's transport emissions registered a 3.1% decrease in 2022, in contrast to the global growth in transport sector emissions.[] And the proportion of carbon emissions from China's transportation industry to the country's total carbon emissions is lower than the world average. This is mainly due to the high proportion of carbon emissions contributed by China's manufacturing industry in the national economy (23.2%) and the large amount of carbon emissions generated by coal-fired power generation and heating (41.6%), according to WRI research. However, as China gradually phases out relatively backward coal-fired units and increases the proportion of green energy sources such as wind and solar power, the carbon emissions from the power generation industry are rapidly decreasing, making the problem of carbon emissions in transportation increasingly prominent.
Road transportation is the highest source of carbon emissions in the transportation industry. According to the data from the IEA, global road transportation emitted 5.86 gigatons of carbon dioxide in 2021, accounting for 76.1% of the total emissions of 7.7 gigatons.[] Petroleum products, as the primary fuel for vehicles, account for 90% of the energy consumption for road transportation. It is noteworthy that electricity provides less than 1% of the energy supply for road transportation. In China, over 60% of diesel and over 90% of gasoline are consumed by road transportation. With the continuous increase in vehicle ownership, carbon emissions from road transportation continue to rise. For example, in China, in 2019, carbon emissions from road transportation, mainly from automobiles, exceeded 700 million tons, an increase of 1.4 and 0.6 times compared to the emissions in 2005 and 2010, respectively.[] The majority of the increase was due to the combustion of gasoline and diesel, and carbon emissions from road transportation are expected to continue to grow at an annual rate of about 1% until 2030. Therefore, controlling carbon emissions from the fuel, that is, gradually replacing ICEVs that use fossil fuels with EVs, is crucial for achieving the decarbonization goals of the transportation industry.[]
In a particular case study presented by the IEA, based on the stated policy scenario (STEPS) and the assumption of EV penetration in the announced pledges scenario (APS), the peak oil demand in the road sector was shifted forward by nearly 10 years, and the oil demand in 2030 was more than 1.5 million barrels per day lower than that in the STEPS.[] Vehicle electrification is key to reducing oil demand in the road transport sector and lowering carbon emissions in the transportation industry. With the application of energy-saving technologies and the large-scale penetration of new energy vehicles, carbon emissions from road transportation are rapidly decreasing. While the participation of EVs in transportation can indeed reduce carbon emissions, given the enormous existing stock of ICEVs, there will inevitably be a long period of coexistence between EVs and ICEVs. Therefore, it is necessary to conduct a specific analysis of the lifecycle carbon emissions of vehicles with different energy types.
Carbon emissions of the vehicle lifecycle
The assessment of vehicle carbon emissions should not be limited to tailpipe emissions during the usage stage, but should consider the environmental impacts of vehicle products from a lifecycle perspective. Currently, the main types of road vehicles are battery electric vehicles (BEVs), ICEVs, and hybrid electric vehicles (HEVs). By comparing the lifecycle carbon emissions of different powertrains, we can better analyze the effects of vehicle types on transportation carbon emissions and find appropriate ways to reduce carbon emissions from road transport.
According to data from China Automotive Technology and Research Center Co., Ltd (CATARC-ADC), from a lifecycle perspective (assuming a vehicle travels 150,000 km during its lifecycle), the sales-weighted carbon emissions of different fuel types of passenger vehicles sold in China in 2021 decreased in the order of diesel passenger vehicles, gasoline passenger vehicles, conventional hybrid passenger vehicles, plug-in hybrid passenger vehicles and electric passenger vehicles (unless otherwise specified, EVs in the article refer to BEVs), as shown in Figure . An EV has the lowest lifecycle carbon emissions, less than half that of a diesel ICEV. With the production and manufacturing capacity in 2021, from material production to maintenance, its lifecycle carbon dioxide emissions are 22.4 tons, while the lifecycle carbon dioxide emissions of gasoline ICEVs that people are familiar with are 39.7 tons. Replacing gasoline ICEVs with EVs will reduce carbon emissions by 43.4% per vehicle. The electrification of vehicles has a significant impact on reducing the lifecycle carbon emissions of vehicles. Based on the average historical data of vehicles (including passenger cars and commercial vehicles) carbon emissions from 2012 to 2021, for every additional one million EVs, the lifecycle carbon emissions in road transport will be reduced by 7.28 million tons and direct carbon emissions from fuel combustion will be reduced by 12.8 million tons. In summary, facing the goal of carbon neutrality, vehicle electrification is an inevitable trend and more and more EVs will replace ICEVs in road transport to reduce transportation sector carbon emissions.
[IMAGE OMITTED. SEE PDF]
However, we found that EVs are not as environmentally friendly as expected, and their lifecycle carbon emissions account for 56.4% of gasoline ICEVs, which is still relatively high. To understand the reasons, we need to analyze each stage of the vehicle lifecycle. Further subdividing the vehicle lifecycle, a vehicle's carbon footprint involves material production, vehicle assembly, vehicle usage, and other stages, as shown in Figure . From the figure, we can see that EVs have significantly lower carbon emissions than gasoline ICEVs during the vehicle usage, which is also the key reason why EVs can reduce carbon emissions. At the same time, the carbon emissions of EVs during the use phase are highly related to the cleanliness of the power grid. Although the proportion of thermal power generation has declined year by year, it still accounted for 65% of China's electricity generation in June 2022 since coal-fired power generation is still dominant, leading to high carbon emissions from the power generation industry. This also leads to unsatisfactory emission reduction effects of EVs. At the same time, we noticed that EVs have significantly higher carbon emissions than ICEVs in material production. Studies have shown that batteries have a significant impact on EV carbon emissions as a core component of EVs. High energy consumption and emissions during battery preparation make carbon emissions from EVs higher than traditional ICEVs during material production.[]
Under the background of carbon neutrality, EVs face significantly different challenges than ICEVs. Figure shows the proportion of carbon emissions at different stages of gasoline ICEVs and EVs. EVs have 36% and 62% of their lifecycle carbon emissions in material production and vehicle usage (calculated by driving 150,000 km), respectively. In contrast, gasoline ICEVs have 15% and 84% of their carbon emissions in these two stages, respectively. EVs should pay more attention to their carbon emissions during material production and component manufacturing, while ICEVs tend to focus on the economic and environmental performance during driving. Due to the low carbon emissions of EVs during vehicle usage, it further magnifies the carbon emissions of battery manufacturing during vehicle material production. With the increasing degree of vehicle electrification, it can be expected that the average proportion of carbon emissions in vehicle material production will gradually increase. But for EVs, due to the large-scale production of power batteries and related components, their carbon emissions during material production may decrease.[] In the short term, carbon emissions from the automotive industry may increase due to power battery production for EVs. However, the advantages of reducing carbon emissions of EVs are reflected in the future usage of vehicles. With the extension of vehicle usage stage, the advantages of low carbon emissions of EVs become more obvious. And with the increase in wind power and photovoltaic power generation in the future, the cleanliness of power system will improve, which can further reduce carbon emissions during EV usage.
In summary, from the comparison of the lifecycle of different energy types of passenger cars, it can be found that vehicle electrification can significantly reduce carbon emissions from automobiles and promote carbon neutrality in the transportation sector. At the same time, it is also noted that EVs are not truly zero-carbon emissions. Power battery manufacturing and power system carbon emissions during use are the main sources of carbon emissions in the lifecycle of EVs.
REDUCING CARBON EMISSIONS FROM VEHICLE INDUSTRY CHAIN
Carbon neutrality strategic goals of world vehicle companies
As the deadline for carbon neutrality approaches, reducing carbon emissions in the automotive industry is becoming increasingly urgent. On March 15, 2022, with the adoption of the Carbon Border Adjustment Mechanism (CBAM) proposal, the world's first officially implemented carbon tariff policy will include all goods under the European Union Emissions Trading System (EU-ETS) in the scope of carbon tariffs.[] This means that the practice of avoiding strict carbon emission restrictions by transferring production to countries or regions with lower carbon emission regulations will no longer be viable.[] With the widespread implementation of carbon taxes, global companies exporting products to the EU are subject to strict carbon emission restrictions. As the most affected energy-intensive industry, the steel and chemical industries are experiencing a significant increase in carbon costs, which has resulted in a significant compression of the profit margins of downstream automotive parts and vehicle manufacturers. This environmental requirement means that the automotive industry must consider the impact of carbon emission regulations throughout the entire lifecycle of development, manufacturing, use, and recycling, rather than just emissions standards during use. Failure to comply with relevant carbon emission management policies in export countries may result in high taxes or even penalties. This objectively accelerates the promotion of low-carbon materials and technologies in the automotive industry.
By adopting new technologies and optimizing supplier systems, major global automakers have formulated their own carbon neutrality plans, hoping to control their profit space by multidimensional and multi-level control of the carbon cost of vehicles in the production stage under the pressure of carbon taxes. Currently, many multinational automakers such as Volkswagen, BMW, Daimler, and Porsche have announced their phased emission reduction plans and the time frame for achieving carbon neutrality. As shown in Table , the Volkswagen Group proposed to reduce the total carbon emissions of its automotive products during their entire lifecycle by 30% compared to 2015, and clearly stated that carbon neutrality will be achieved by 2050. The BMW Group has achieved carbon neutrality in its global factories by the end of 2021 and plans to reduce carbon emissions per vehicle to two-thirds of the 2019 level by 2030. Porsche announced that it will achieve carbon neutrality across the entire value chain by 2030 and requires its suppliers to use sustainable energy sources to reduce carbon emissions during the production process. Daimler achieved carbon neutrality in its European factories in 2022 and will achieve carbon neutrality for its passenger car products by 2039. Volvo announced that it will become a global climate-neutral enterprise before 2040. Nissan announced that its entire group enterprise operation and product lifecycle will achieve carbon neutrality by 2050. General Motors announced that it will stop selling gasoline-powered vehicles by 2035 and achieve zero carbon emissions for its products in the same year. As the first Chinese automaker to explicitly set a timeline for carbon neutrality, Great Wall Motors announced that it will achieve carbon neutrality by 2045, and the carbon neutrality timelines of other Chinese automakers are also mostly concentrated around 2045, which is relatively stable compared to all automakers that have announced carbon neutrality timelines.
Table 3 Carbon neutrality plans of global automakers.
| Car company | Carbon neutrality plan |
| Volkswagen | Reduce total carbon emissions by 30% from 2015 levels for the entire lifecycle of its vehicles by 2025. Deliver 22 million EVs worldwide by 2028. Launch around 70 electric models by 2030. Achieve carbon neutrality across the entire group by 2050. |
| BMW | 25% of vehicles sold in China will be electric by 2025. Reduce average carbon emissions per vehicle by at least one-third by 2030 compared to 2019 levels. |
| Daimler | All European factories to achieve carbon neutrality by 2022. More than 50% of group sales from new energy vehicles by 2030. Stop selling internal combustion engine passenger cars by 2039 and achieve carbon neutrality for all passenger cars by then. |
| Volvo | Full electrification by 2025, with 50% of sales being fully EVs. Become a pure electric luxury car company by 2030. Achieve climate neutrality across the entire value chain by 2040. |
| Porsche | Net-zero emissions across the entire value chain by 2030. Requires suppliers to use renewable energy in production. |
| Nissan | Net-zero emissions across the entire company's operations and product lifecycle by 2050. |
| General Motors | Motors Stop selling gasoline-powered cars by 2035 and transition to zero-emission and EVs. |
| Kia | Net-zero emissions by 2045. |
| Lexus | 2022 is the brand's first year of electrification, with plans to launch new platform fully electric models in 2023. |
| Great Wall Motor | Build its first zero-carbon factory in 2023. Launch more than 50 new energy vehicle models by 2025, and new energy vehicles account for 80% of new car sales. Achieve carbon neutrality by 2045. |
| Dongfeng Motor | Reduce carbon emissions intensity by 15% by 2025. By 2024, 100% of its main passenger car brands will be electrified, and sales of new energy vehicles are expected to reach 1 million units by 2025. |
| Guangzhou Automobile Group | Announced the “Green and Clean Plan,” plans to build its first zero-carbon factory by 2023 and achieve carbon neutrality by 2050. |
| Changan Automobile | Reach sales of 3 million vehicles by 2025, of which 35% will be new energy vehicles. Carbon emissions will peak in 2027, and carbon neutrality will be achieved by 2045. |
| BYD | Successfully built China's first zero-carbon industrial park in August 2022. Achieve zero carbon emissions by 2050. |
| Geely Group | Increase the use of green electricity to 40% by 2025 and achieve carbon neutrality across the entire value chain by 2045. |
| SAIC Motor | Achieve carbon emissions peak by 2025, with new energy vehicle sales accounting for more than 32% of total sales. |
| FAW Group | Reach near-zero carbon emissions by 2053, with a focus on hydrogen fuel cells for its commercial vehicle department. |
| Beijing Automotive Group | Achieve carbon emissions peak by 2025 and complete carbon neutrality across all products by 2050. |
It is worth noting that, in addition to optimizing suppliers and promoting low-carbon emission materials, the establishment of “zero carbon emission factories” serves as a pivotal milestone in the decarbonization timeline of all Chinese automakers. “Zero carbon emission factory” refers to a factory that achieves comprehensive zero carbon emissions performance through technical measures such as energy conservation, emission reduction, and carbon elimination during the production and manufacturing process. By adjusting energy structure and adopting low-carbon processes, Great Wall Motors plans to build the first zero-carbon emission factory in 2023, and establish a circular recycling system for the automobile industry chain. Guangzhou Automobile Group plans to build the first zero carbon emission factory in 2023 and achieve carbon neutrality by 2050. In August 2022, BYD successfully built the first zero carbon emission park for Chinese automobile brands, reducing carbon emissions by 245,681.89 tons of carbon dioxide, and plans to achieve zero carbon emissions by 2050. Geely Group aims to increase the utilization rate of green electricity to 40% by 2025, explore whole-vehicle low-carbon repair and remanufacturing of parts, and build a circular industry that spans from R&D to marketing and remanufacturing, with the goal of achieving full-chain carbon neutrality by 2045.
In the entire lifecycle of automotive products, automakers cannot directly control the carbon emissions generated during vehicle usage. However, researchers have found that carbon emissions during the usage phase of EVs are significantly lower than those of ICEVs by comparing the lifecycle carbon footprints of different vehicle types. Therefore, the transformation of products to electrification has become a key strategy for some automakers in their carbon neutrality plans. Volkswagen plans to launch approximately 70 EV models by 2030. BMW plans for 25% of the vehicles it sells in China to be EVs by 2025. Daimler plans for new energy vehicles to account for more than 50% of total sales before 2030. Great Wall Motors plans to launch more than 50 new energy vehicle models by 2025, with new energy vehicles accounting for 80% of sales. SAIC aims for new energy vehicle sales to account for over 32% of sales by 2025. Some automakers have set aggressive deadlines for discontinuing the sale of traditional ICEVs to transition all their products to new energy vehicles such as HEVs and BEVs in the shortest possible time. Daimler announced that it will stop selling traditional internal combustion engine passenger cars by 2039 to achieve carbon neutrality in its passenger car division. General Motors plans to stop selling gasoline ICEVs by 2035, with its products transitioning to zero-emission vehicles. Volvo plans for all its vehicle models to be fully electrified by 2025, with BEV models accounting for 50%. Dongfeng Motor plans for its main passenger car models to be 100% electrified by 2024.
In addition to focusing on the development of EVs, auxiliary technologies such as lightweight vehicle structures, efficient inverters, and regenerative braking systems provide potential pathways for reducing carbon emissions during the usage phase of vehicles.[] However, the use of electricity in EVs already includes carbon costs, and the cleanliness of the electricity used is not included in the carbon accounting scope of automobile companies. This means that even if the automotive industry achieves complete carbon neutrality, EVs cannot be truly clean. Therefore, to achieve carbon neutrality in the automotive industry, the main focus of vehicle manufacturers should still be on reducing carbon emissions during the production of automobile components and vehicles, supplemented by the carbon emissions from automobile marketing and maintenance. In other words, to achieve complete greenness of automobiles, continuous technological breakthroughs in upstream industries such as energy are still required. To truly implement a carbon neutrality strategy in the automotive industry, synchronized efforts at different positions in the industrial chain are necessary to achieve the best results.
Carbon neutrality actions and achievements of automotive companies
According to the classification of upstream, midstream, and downstream in the industry chain, the vehicle manufacturing industry is in the midstream of the entire industry chain. The establishment of green factories is the key to achieving carbon neutrality in the vehicle manufacturing. Further reducing the carbon emissions of downstream automotive product marketing and maintenance departments is only an embellishment of the former's achievements. Finally, by increasing environmental requirements for upstream parts and giving priority to parts with lower carbon footprints, vehicle manufacturers can truly consolidate their carbon neutrality achievements and achieve the goal of reducing the overall lifecycle carbon footprint of vehicles, as shown in Figure . This will objectively accelerate the promotion of low-carbon processes and low-carbon materials in the upstream industry. We will discuss these points in detail in the following sections.
[IMAGE OMITTED. SEE PDF]
Establishing green vehicle plants to achieve carbon neutrality
Establishing green factories is the core strategy for reducing carbon emissions in the production process. As a preliminary stage towards achieving carbon neutrality, controlling and reducing carbon emissions in the production process through the implementation of green factories is the first step for automobile manufacturers to reach their carbon neutrality targets.[] Divided by implementation measures, it specifically includes:
- (1)
Emissions reduction: reducing the emissions of volatile organic compounds (VOCs) during the manufacturing process. For example, using water-based paint in the vehicle coating process to avoid organic solvent emissions, or installing organic gas adsorption devices in the coating workshop to reduce gas leakage, thus fully meeting emission requirements and achieving green environmental protection.[]
- (2)
Energy conservation: managing factory energy consumption based on production plans, and implementing timed opening and closing of electricity facilities such as workstation lighting, air conditioning, and drying ovens to avoid unnecessary energy waste.
- (3)
Clean energy substitution: through relevant infrastructure improvements, such as installing solar panels on the factory roof and wind power facilities in the plant, using clean energy such as solar and wind power to replace grid electricity.[]
- (4)
Purchasing carbon credits: offsetting carbon emissions during the manufacturing process by purchasing carbon credits from relevant organizations. In addition to implementing energy-saving and solar energy projects, for the current situation where complete substitution with green energy is temporarily not feasible, automobile manufacturers can also support clean energy development projects and assume their carbon reduction responsibilities by purchasing green energy and carbon credits from relevant organizations.
As for short-term goals, SAIC Volkswagen proposed a green factory construction target of reducing 20% of five key environmental indicators, including energy, water, carbon dioxide, VOCs, and waste, by applying environmentally friendly and energy-saving technologies. These technologies mainly include 100% direct purchase of hydroelectricity, solar photovoltaic power generation, wind energy utilization, cogeneration of heat and power, and waste heat recovery. These technologies can reduce the carbon emissions of automobile products by 60%, and the cogeneration of heat and power using natural gas can help reduce carbon emissions by 12,000 tons per year. Currently, new green automotive manufacturing bases based on these technologies have gradually been put into operation. Taking Xiaopeng's Zhaoqing plant as an example, the advanced pretreatment film technology used in its coating workshop has reduced the amount of waste paint sludge by 94% and reduced energy consumption by over 25%, while achieving 100% utilization of recyclable solid waste. In November 2021, the distributed photovoltaic power generation project supporting the Xiaopeng Zhaoqing plant was officially connected to the grid. By utilizing the idle space of the production base, distributed photovoltaic systems were built on the roofs and parking lots of assembly and welding workshops, with a total installed capacity of 20.735 MW and an expected annual power generation of 21.33 million kWh, which can meet 30% of the production plant's electricity demand and is equivalent to saving 6515 tons of standard coal and reducing 17,512 tons of carbon dioxide emissions per year.
Carbon neutrality in sales and maintenance processes
As a downstream industry in the automotive supply chain, the carbon emissions generated by the sales and maintenance of automotive products are also an important part of the automotive carbon footprint. Their carbon footprint mainly originates from the energy consumption during the product marketing process, the carbon cost of the storefront itself, and the low-reusability paper promotional materials and disposable plastic products used in automotive product marketing and maintenance. These potential resource wastages can increase the carbon emissions of automobiles throughout their lifecycle.
To address these issues, automakers have already required their dealerships to take targeted “green measures,” and some of these measures have already shown effects. BMW launched the “BMW Green Star” program in China in 2022, which provides dealers with solutions for emissions reduction and carbon reduction in four areas: green environment, green energy, green operations, and green practices. Through energy-saving design, efficient lighting, zoning intelligent control, and efficient sanitary water recycling systems, dealerships have generally achieved the green environment target of 10% electricity savings and 15% water savings. By requiring dealerships to increase the proportion of green electricity in their electricity consumption and awarding “Green Store Star” certification to dealerships with over 80% daily energy consumption coming from green electricity, the proportion of dealerships using new energy has significantly increased. At the same time, by requiring dealerships to meet the standards for the entire process of green operations including paperless office, digital display, and the elimination of traditional “three-piece set” of disposable steering wheel covers, seat covers, and foot pads for after-sales services. The concepts of “green practices” have also been promoted in sales and maintenance processes. The effectiveness of these measures in carbon emissions reduction has also been confirmed by research conducted by Sen et al.[] As related concepts and measures continue to be created, expanded, and disseminated, their contribution to achieving carbon neutrality targets will continue to increase over time.
In addition to actively practicing green and low-carbon development, FAW-Volkswagen also extends its environmental protection actions to the upstream and downstream of the industry chain. As the first company in China to set the standard of “Green Partner” for dealers, FAW-Volkswagen has adopted an evaluation system and free training. Through vigorous promotion and active advocacy, dealers can effectively implement the concept of energy saving and environmental protection in every aspect of network construction, sales and after-sales, reduce pollution to the environment and consumption of nonrenewable resources, so that green and low-carbon initiatives are gradually scaled up and systematized. Mercedes-Benz is also working with its dealer partners to promote green retail projects. We are gradually promoting sustainable retail development by saving energy and reducing emissions, using environmentally friendly recyclable materials and producing clean energy. More and more dealership stores are applying green measures such as air-source heat pumps, water-saving facilities, solar photovoltaic, and elimination of disposable paper cups. To further promote the green retail program, Mercedes-Benz has also introduced a full range of sustainability guidance measures and certified the relevant achievements of dealers to further motivate them.
Carbon neutrality of automotive parts suppliers
As shown by the carbon footprint of the lifecycle of a vehicle, the carbon emissions generated during the production of automotive parts and raw materials far exceed those produced during the vehicle manufacturing process, which is further exacerbated in the case of EVs. While pure EVs do not produce carbon emissions during fuel production and use, the carbon emissions associated with their core component, the power battery, cannot be ignored. And due to the lower energy density of power batteries compared to fuel, EVs require a large number of batteries to ensure their range, which significantly increases the carbon cost of the vehicle while also increasing the manufacturing cost of EVs.[] Taking measures to control the carbon cost of the power battery component, particularly upstream in the automotive manufacturing industry chain, is a critical step in achieving carbon reduction throughout the EV lifecycle.[]
European automakers such as BMW, Mercedes-Benz, Volkswagen, and Volvo have set specific requirements for the carbon footprint of the power batteries used in their vehicles. By around 2024, the carbon emissions per kWh should be reduced to 40–50 kg, and zero emissions should be achieved by 2040. According to data released by the European Federation for Transport and Environment, the decarbonization level of the power grid directly affects the carbon emissions of the battery production and assembly processes.[] Compared to electricity generated from traditional energy sources, the use of clean energy can significantly reduce the carbon costs of downstream products.[] For instance, the carbon emissions of LIBs and NiMH batteries produced in Japan are lower than those produced in China and South Korea.[] By installing photovoltaic and wind turbines for power generation to replace fossil fuel-based electricity, or purchasing green electricity to further optimize the energy structure of production, carbon emissions from the production process of power batteries have been effectively controlled. From 2019 to 2020, Contemporary Amperex Technology Ltd (CATL) reduced its cumulative carbon emissions by 210,252 tons through energy conservation, emission reduction, and photovoltaic power generation. Since July 2021, CATL has been using only green electricity in the production process of the battery cells supplied to BMW's iX3 model.
In addition to optimizing the production energy structure, research on new battery material systems and upgrading manufacturing processes can also reduce the carbon footprint of batteries. Studies have shown that for NMC and LFP batteries, a significant amount of carbon emissions is produced during the electrode active material vacuum drying and coating drying processes, making it one of the main carbon emission stages in battery manufacturing.[] Increasing the drying speed or energy utilization efficiency during electrode drying can reduce carbon emissions in the battery manufacturing process. At the same time, researchers have found that the carbon footprint of electrode material production for emerging sodium-ion, Li-O2, and Li-S batteries is lower than that of the current mainstream NMC and LFP batteries due to differences in material production energy consumption.[] These provide new options for reducing battery manufacturing carbon emissions for suppliers. In addition, research has also shown that significant reductions in carbon emissions in the battery stage can be achieved through the echelon utilization of power batteries and increasing the recycling rate of related resources.[] For example, using recycled packaging for battery cells instead of one-time use cardboard boxes. In addition, recycling of waste batteries to recover valuable and high-energy-consuming metal materials such as nickel, cobalt, lithium, and manganese from retired power batteries and putting them back into the battery recycling process. These positive actions taken by suppliers can be seen as the result of both policy and market pressures.
GREENER EVs FOR THE FUTURE
It is easy to see from the lifecycle carbon footprint of EVs that whether an EV is truly low-carbon and environmentally friendly depends to a large extent on the carbon footprint of its power battery, in addition to being influenced by the electricity mix, and that achieving systematic emissions reductions throughout the battery lifecycle is the key to making EVs greener.
It is generally accepted that the lifecycle of a power battery consists of raw materials, manufacturing, onboard application, and disposal. Studies have shown that carbon emissions and solid pollutants from raw material processing, battery manufacturing, and disposal account for the majority of the lifecycle. Kim et al.[] report the first cradle-to-gate emissions assessment for a mass-produced battery in a BEV, as shown in Figure . The study found that the production of cell components and cell manufacturing accounted for more than 60% of the lifecycle carbon dioxide. At the same time, according to existing standards in China, power retired from EVs and entering the disposal process still has around 80% of its usable capacity, and has great potential for use in other application scenarios. Reducing carbon emissions from raw materials and production is therefore as important as improving the echelon utilization of retired batteries in the lifecycle of power battery emissions reduction. By introducing echelon utilization as well as recycling into the traditional process, recycled materials are put back into remanufacturing, making the lifecycle of the battery a closed loop, as shown in Figure . The joint vehicle-cloud SOH estimation to realize the management of the battery lifecycle will help to seamlessly integrate the above two stages of carbon reduction and maximize the effect of emission reduction.
[IMAGE OMITTED. SEE PDF]
[IMAGE OMITTED. SEE PDF]
Greener batteries and finer management
Reducing carbon emissions in battery manufacturing
Studies have shown that most of the greenhouse gas emissions from batteries are caused by the cradle-to-gate stage,[] and in Table we list the carbon emissions of batteries from cradle-to-gate. By assessing the carbon emissions of EV batteries, the researchers found that the cradle-to-gate greenhouse gas emissions of the 24 kWh lithium-ion battery used in the Ford Focus model were 3.4t of carbon dioxide equivalent. Battery manufacturing was the main contributor, accounting for 45% of the total greenhouse gas emissions. This continues to be the case for new power batteries using all-solid electrolytes. Troy et al.[] found that a large proportion of the total emissions from the new all-solid-state batteries came from the power efficiency and material consumption during production. Details of the carbon emissions from the cradle-to-gate stage of the battery in each of the major battery producing countries/regions are presented in Table (Since past studies have measured the carbon footprint per unit weight of the battery, and also the weight of the battery pack. So here we use “Function unit” to label the units of carbon emissions). Further research has shown that the fabrication of electrode materials (especially the positive active material), wrought aluminum, and electrolyte are the main contributors to greenhouse gases at this stage,[] with the vacuum drying and coating drying processes being the two main carbon emitting processes in the fabrication of electrode materials.[]
Table 4 Carbon emissions from the cradle-to-gate process of the battery.
| Country/Region | Function unit | Batteries | Carbon emissions | Reference |
| China | 1 kWh | LFP | 76.7 kg CO2-eq | [] |
| NMC | 87.1 kg CO2-eq | |||
| China | 26.6 kWh | NMC333 | 179.7 kg CO2-eq/kWh | [] |
| NMC622 | 160.2 kg CO2-eq/kWh | |||
| NMC811 | 140.3 kg CO2-eq/kWh | |||
| Korea, USA | 1 kg | LMO/NMC | 11.3 kg CO2-eq | [] |
| 1 kWh | LMO/NMC | 141 kg CO2-eq | ||
| Japan | 1 kg | LIBs | 8.27 kg CO2-eq | [] |
| Japan | 11.4 kWh | NMC-LMO | 313 kg CO2-eq | [] |
| Europe | 27 kWh | NMC111 | 65 kg CO2-eq/kWh | [] |
| USA | 1 kWh | NCA, NMC, LMO, LFP, LMO–LTO | 194–494 kg CO2-eq | [] |
| [-] | 1 kWh | Li-S | 67.94 kg CO2-eq | [] |
| SIBs | 64.35 kg CO2-eq | |||
| Li-O2 | 10.15 kg CO2-eq |
Considerable work has been undertaken by both manufacturers and research institutes to reduce carbon emissions at the cradle-to-gate stage. Studies have shown that there are significant differences in carbon emissions at this stage between different battery materials, provided similar processes are used.[] For example, for NMC and LFP batteries, the cathode material contributes more than 35% of the global warming potential (GWP), while the cathode only accounts for 12% of the emissions from NiMH battery production.[] The carbon emissions in the manufacturing phase of NMC111 batteries are higher than those of nickel-sodium chloride batteries due to differences in the amount of active cathode material, aluminum, and copper used in the battery production process and energy consumption in production.[] Further comparing the eight different battery materials Ni-MH, Li1.2Ni0.2Mn0.6O2/C, LiNi1/3Co1/3Mn1/3O2/C, LiNi0.8Co0.2O2/C, LiFePO4/C, LiFe0.98Mn0.02PO4/C, FeF3(H2O)3/C, and NaFePO4/C, as shown in Table . The best carbon footprint characteristics were obtained from the NaFePO4/C cell when 1 kg of cathode material was synthesized, while the opposite was true for NiMH.[] Therefore, the development of more environmentally friendly battery materials has a crucial role to play in reducing carbon emissions at the cradle-to-gate stage of batteries, and carbon emissions from the mass production of batteries should be included in battery evaluation criteria along with battery performance when improving existing batteries and developing new ones.
Table 5 Comparison of the eight batteries on carbon footprint (CFP) value (kg CO2-eq).
| Battery materials | Ni-MH | LiFePO4/C | LiFe0.98Mn0.02PO4/C | FeF3(H2O)3/C |
| CFP | 170.680 | 94.366 | 69.286 | 66.109 |
| Battery materials | Li1.2Ni0.2Mn0.6O2/C | LiNi1/3Co1/3Mn1/3O2/C | LiNi0.8Co0.2O2/C | NaFePO4/C |
| CFP | 17.420 | 17.022 | 13.621 | 5.431 |
Refined onboard battery management
When discussing the emission reduction benefits of EVs, it is easy to overlook the management of batteries during their application in vehicles. The reason for this is that the carbon emissions in the usage of EVs are relatively small in the overall lifecycle. However, from the point of view of the lifecycle of power batteries, the application in vehicles is an important bridge between the manufacturing process and the recycling process. Extending the service life of power batteries in EVs and providing targeted suggestions for their postretirement echelon utilization will undoubtedly be of great significance in reducing carbon emissions throughout the lifecycle of power batteries. Achieving refined management of power batteries in EVs is the crucial way to achieve these goals.
To realize the refined management of power batteries, the battery management system (BMS) is required to integrate the functions of nondestructive battery inspection, functional maintenance, and fault warning, so as to realize the efficient application of power batteries while preparing for the echelon utilization after retirement. This not only requires the BMS to be able to accurately predict the battery attenuation path under dynamic working conditions, but also to be able to know the internal state of the battery at any point on the predicted attenuation path. The use of nondestructive testing techniques to obtain the internal state of the battery and to overcome the edge distortion of the predicted attenuation path generated by the dynamic uncertainty of the working conditions is the key to achieving above goals. Deep learning algorithms are widely used in battery SOH estimation because of their better prediction capability of digital signal characteristics and their ability to overcome the edge distortion problem of traditional empirical algorithms under dynamic working conditions.[] Xu et al.[] developed a fast method for predicting battery capacity decay based on a long short-term memory neural network (LSTM) with good predictive capability for temporal signals, incorporating battery aging mechanisms, and were able to complete battery life estimation using a charging voltage signal of about 2 min. To achieve accurate estimation of the internal state of the battery during driving, nonintrusive nondestructive testing techniques centered on characteristic signals or reaction mechanism models have become a hot research topic.[] Dai et al.[] conducted a systematic study of battery electrochemical impedance spectroscopy (EIS) to characterize the internal aging phenomenon of batteries using EIS properties and combined with machine learning algorithms to achieve accurate estimation of battery SOH. Xiong et al.,[] on the other hand, target the difficult problem of battery performance estimation at low voltages by using the solid-phase diffusion equation based on the surface SOC to describe the open-circuit voltage variation of the battery, combined with an equivalent circuit model to achieve the battery state estimation at low SOC. And Yang et al.[] proposed a cloud-based management framework namely cyber hierarchy and interactional network (CHAIN). The cloud server can store massive historical data, update the data set in time by receiving BMS information, and perform complex operations (such as complicated model simulation and deep learning methods) to achieve iterative optimization under various applications.[] The BMS can realize real-time status estimation, RUL prediction, equalization management, and thermal management based on cloud information.
Under the premise of accurate prediction of the internal and external state of the battery, implementing the decision into practical management is also an important research element of refinement management. Considering the effects of operating temperature, cycle depth, and average state of charge during the cycle on battery life, effective thermal management, and charge/discharge management can effectively extend battery lifespan, maintain basic battery functions and thus improve its ability to reduce carbon emissions.[] Wang et al.[] proposed to use multi-stage alternating current to heat the low-temperature battery and make the battery rise from −20°C to 0°C in 5 min without depleting the battery SOH. Xiong et al.[] used genetic algorithms to optimize the battery's self-heating strategy, reducing the above heating time to 70 s, and only attenuating 7.72% of capacity per 200 heats. The battery self-heating technology can quickly raise the battery temperature to the appropriate range, while the EV power exchange technology can extend the battery life by allowing the battery to be charged under optimal working conditions, and it can avoid peak electricity consumption or intermittent renewable energy to indirectly reduce carbon emissions, making the battery swapping technology a very promising development route for EV charging.[] To ensure the safe operation of EVs, fault detection and early warning of the BMS is an indispensable function for refinement management. Yu et al.[] combined least squares method with a traceless Kalman filter to estimate the fault current of the current sensor to achieve rapid diagnosis of hardware faults in the BMS and improve the safety of EV.
Diversified utilization and more efficient recycling
Battery echelon utilization
Generally speaking, when the health status of a battery is lower than a specific threshold, the battery cannot provide sufficient power or energy to complete its expected functions, reaching its service life.[] Since retired EV batteries still contain 70%–80% of their remaining capacity, they are suitable for less demanding energy storage systems, such as communication base stations, building energy storage, photovoltaic energy storage, microgrids, and so on.[] It can also be applied to the power source of low-speed vehicles, such as electric bicycles, low-speed scooters, urban sanitation vehicles, and so on, as shown in Figure .
[IMAGE OMITTED. SEE PDF]
Research has shown that the secondary utilization of batteries can generate positive and considerable environmental benefits.[] With additional application scenarios and working hours, echelon utilization can spread the carbon footprint during battery manufacturing. Under conservative estimates, echelon reuse of LIBs in stationary energy storage can reduce GWP by 15%. When under ideal refurbishment and reuse conditions, it can reduce it by 70%.[] Without considering the echelon utilization scenario, NMC batteries have the highest carbon footprint of all LIB types. In the echelon utilization, the carbon footprint of NMC batteries is comparable to that of NCA batteries, being only 32%–51% higher than that of LMO batteries. Ioakimidis et al.[] evaluated four scenarios for the echelon utilization of LFP batteries. (i) Secondary use of EV batteries or manufacturing of new batteries as energy storage units in buildings. (ii) Energy supply using Spanish electricity or solar PV panels. The results show that reusing existing EV batteries in secondary use results in significant environmental benefits. Wilson et al.[] compared the carbon emissions produced by Australian repurposed EV batteries with those of the original fixed batteries of the same capacity and found that the carbon footprint of the repurposed batteries was smaller, provided they had been in operation for at least 6 years. Currently, there are two main technological routes for echelon utilization, as shown in Figure for the manufacturing segment of echelon utilization batteries. (a) Echelon utilization at the cell level. First, the retired power batteries are disassembled into cells. Then, the capacity, internal resistance, and other parameters of the cells are tested or estimated, and these cells are classified according to one or more of these indicators. Finally, the cells are reconstituted for echelon utilization.[] (b) Echelon utilization at the module level. The module is used directly as a base unit for testing, sequencing, and reorganization. Due to the immaturity of the technology, the consistency of the battery capacity produced in the early years is low when they are retired. In this case, technology route (a) is an ideal solution. With the advancement of battery materials and manufacturing processes, there is little difference in the consistency of cells in the same retired battery module, making technology route (b) the mainstream solution. The reduction of labor and time costs for battery disassembly and reconstitution improves the economic efficiency of echelon utilization. However, even after significant improvements in battery uniformity, there are still many challenges to be faced in the echelon utilization,[] which can be summarized as follows: (1) The diversity of battery materials, structures, and manufacturing processes of retired batteries increases the difficulty of secondary utilization. (2) Historical data of batteries are often missing or fragmented, which makes it difficult to accurately assess the health condition and residual value of retired batteries. (3) The retired LIBs may be in accelerated aging period during the secondary utilization,[] which brings potential safety hazards. (4) The price of new batteries is decreasing posing a challenge to the necessity and economics of the echelon utilization. At the end of the battery's lifespan, the battery capacity will enter a nonlinear decay period.[] And to ensure the safety during secondary utilization, the internal state of the retired battery and its available residual value must be accurately obtained. In addition to the nondestructive inspection methods based on battery management systems mentioned in Section , many invasive inspection methods still play an important role in this field. By implanting smart sensors into the battery,[] the internal state of the battery can be easily measured. For example, sensors are used to capture the internal chemical and thermal processes of the battery to detect the growth of passivation films inside the battery and determine the battery attenuation status.[] These techniques bring great convenience to the performance assessment of retired LIBs. However, these techniques are mainly used for single cells and are not effective enough for estimating the state of the modules. The emergence of more convenient and accurate battery condition estimation techniques in the future may bring new opportunities for battery echelon utilization and more environmentally friendly EVs.
Battery end-of-life recycling
After the completion of the echelon utilization, the battery will enter the final end-of-life stage, whether the solid pollutants generated by disassembly can be turned into treasure, the final battle of carbon emission reduction for the whole lifecycle of the battery. Recycling nickel, cobalt and lithium, and other metal elements in end-of-life batteries for the manufacture of new batteries will not only reduce carbon emissions, but also generate huge environmental and economic benefits.[] Studies have shown that recycling batteries after echelon utilization can reduce the lifecycle carbon footprint of LIBs by 8%–17%.[] The contribution of LIBs to the environmental friendliness of EVs throughout their lifecycle remains to be further analyzed. The global warming potential of the battery is 216.2 kg CO2/kWh in the production phase, 94.2 kg CO2 eq/kWh in the use phase, and −17.18 kg CO2 eq/kWh in the recycling phase (Negative values indicate that the recycling phase is beneficial to the environment).[] This means that recycling valuable materials can bring benefits and reduce carbon emissions.
For batteries with different chemical compositions, an appropriate recycling process needs to be selected to obtain the best output quality and the highest environmental benefit.[] Several studies have explored the carbon reduction potential of three common recycling processes (pyrometallurgy, hydrometallurgy, and direct physical recycling) with different types of batteries. Studies have shown that pyrometallurgical recovery is inefficient and has high carbon emissions due to the energy consumption of high-temperature treatment and will also lose lithium in the slag.[] However, there are different conclusions about the environmental benefits of the two battery recovery processes: hydrometallurgy and direct physical recycling. Quan et al.[] conducted LCA studies on LFP and NMC batteries. It was concluded that for LFP and NMC battery recycling processes, hydrometallurgy has better environmental advantages than pyrometallurgy and direct physical recycling and should be recommended. In the case of NMC batteries, for example, the steel, copper, and aluminum in the batteries cannot be well recycled by pyrometallurgical methods. Moreover, a large amount of lithium carbonate is consumed to regenerate the cathode material. However, some researchers believe that direct physical recycling is the most effective method to reduce the lifecycle environmental impact. For example, direct physical recycling of NMC111, NMC622, NMC811, and NCA batteries can reduce greenhouse gas emissions by up to 29.27%–38.15%, achieving the greatest potential for carbon reduction.[] Pyrometallurgical and hydrometallurgical recycling processes do not significantly reduce life-cycle GHG emissions from NMC-622, NCA, and LFP cells, but direct physical recycling has the potential to reduce emissions and be economically competitive.[] Kurz et al.[] evaluated the ecological performance of a direct recycling process based on water jetting and found that recycling 1 kg of power cell is associated with a GWP of 158 g CO2-eq, which is 8–26 times lower compared to conventional hydrometallurgical or pyrometallurgical processes. When 10% and 20% of the recycled material is used in new batteries, respectively, the GWP of power cells can be reduced by 4% and 8%, respectively. In addition, it is critical to increase the recycling rate regardless of the recycling process. Studies have shown that if the recycling rate is increased from 25% to 90%, carbon dioxide emissions from Ni-Cd batteries will be reduced by 30%.[] In general, encouraging the recycling of end-of-life batteries and increasing the recycling rate is important to reduce the lifecycle carbon footprint of batteries. However, in the actual recycling process, the assessment metrics and the chemical composition of the batteries should also be fully considered to select the appropriate recycling process.[]
CONCLUSION AND OUTLOOK
This paper explores the importance and potential ways of achieving lifecycle emission reductions from EVs in the context of carbon neutrality, and suggests that electric mobility is the only way forward for the automotive industry to meet both environmental and market demand. This paper systematically reviews carbon accounting standards, compares the emission reduction impact of EVs from a lifecycle perspective, analyzes the key drivers of carbon emissions from EVs and discusses measures to further reduce vehicle carbon emissions. It is hoped that this will provide further impetus to the transport sector and help achieve the target of carbon neutrality. The main findings are as follows.
- ①
From a lifecycle carbon emissions perspective, EVs have much lower carbon emissions than ICEVs, and vehicle electrification does reduce carbon emissions in the transportation sector. However, the emission reduction effect of EVs is not as good as expected. This is due to the high carbon emissions from the manufacture of EV components.
- ②
At the enterprise level, the establishment of green factories can effectively reduce carbon emissions in vehicle assembly through measures such as the introduction of green electricity and the improvement of environmentally friendly processes. Along the automotive industry chain, green marketing and low-carbon production initiatives implemented by downstream automotive 4S shops and upstream automotive suppliers can also reduce carbon emissions throughout the lifecycle of EVs.
- ③
Battery lifecycle emission reduction is the key to achieving low-carbon EVs, which requires close cooperation between the four stages of the battery from cradle-to-gate, on-board application, and echelon utilization and recycling. Through a comprehensive effort from materials, manufacturing processes, and management, to create a lower carbon cost battery, so that EVs are truly green.
As EV ownership continues to grow, the complete replacement of ICEVs with EVs has become an inevitable trend. The electrification of automobiles has become the single most important contributor to the reduction of carbon emissions from road transport and plays a key role in achieving global carbon neutrality targets. The promotion of green factories, the substitution of clean electricity, the research and development of advanced power batteries, and the continuous progress of refined management technology and echelon utilization technology make it possible to achieve carbon emission reduction in the entire lifecycle of EVs. As low-carbon technologies evolve and more companies participate in carbon neutral initiatives, EVs will become greener, helping to reduce carbon emissions in the transportation sector and achieve global carbon neutrality goals.
AUTHOR CONTRIBUTIONS
Conceptualization: Siyan Chen. Methodology: Siyan Chen. Writing—original draft preparation: Zhenhai Gao. Writing—review and editing: Haicheng Xie and Xianbin Yang. Formal analysis: Haicheng Xie. Visualization: Lisheng Zhang, Hanqing Yu, and Wentao Wan. Data curation: Yongfeng Liu and Youqing Xu. Supervision: Bin Ma and Xinhua Liu. All authors have read and agreed to the published version of the manuscript.
ACKNOWLEDGMENTS
The authors are very grateful to the Science and Technology Development Project of Jilin Province (20200501012GX) and Technology Development Project of State Grid Jilin Electric Power Company Limited to support this work.
CONFLICT OF INTEREST STATEMENT
The authors declare no conflict of interest.
K. A. Mar, N. Schäpke, C. Fraude, T. Bruhn, C. Wamsler, D. Stasiak, H. Schroeder, M. G. Lawrence, WIREs Clim. Change 2023, 14, [eLocator: e832].
A. W. Naylor, J. Ford, Reg. Environ. Change 2023, 23, 38.
M. Meinshausen, J. Lewis, C. McGlade, J. Gütschow, Z. Nicholls, R. Burdon, L. Cozzi, B. Hackmann, Nature 2022, 604, 304.
A. Wyns, J. Beagley, Lancet Planet. Health 2021, 5, [eLocator: e752].
L. Chen, G. Msigwa, M. Yang, A. I. Osman, S. Fawzy, D. W. Rooney, P. S. Yap, Environ. Chem. Lett. 2022, 20, 2277.
J. M. Chen, Innovation 2021, 2, [eLocator: 100127].
IEA. Greenhouse Gas Emissions from Energy Data Explorer 2021. https://www.iea.org/data-and-statistics/data-tools/greenhouse-gas-emissions-from-energy-data-explorer
C. Hepburn, Y. Qi, N. Stern, B. Ward, C. Xie, D. Zenghelis, Environ. Sci. Ecotechnol. 2021, 8, [eLocator: 100130].
M.‐T. Huang, P.‐M. Zhai, Adv. Clim. Change Res. 2021, 12, [eLocator: 281].
P. Smith, L. Beaumont, C. J. Bernacchi, M. Byrne, W. Cheung, R. T. Conant, F. Cotrufo, X. Feng, I. Janssens, H. Jones, M. Kirschbaum, K. Kobayashi, J. LaRoche, Y. Luo, A. McKechnie, J. Penuelas, S. Piao, S. Robinson, R. F. Sage, D. J. Sugget, S. J. Thackeray, D. Way, S. P. Long, Global Change Biol. 2022, 28, 1.
Nat. Rev. Mater. 2021, 6, [eLocator: 959].
N. K. Arora, I. Mishra, Environ. Sustain. 2021, 4, 585.
S. Mallapaty, Nature 2020, 586, 482.
IEA. Global EV Outlook 2021. https://www.iea.org/reports/global-ev-outlook-2021
X. Xia, P. Li, Sci. Total Environ. 2022, 814, [eLocator: 152870].
S. Verma, G. Dwivedi, P. Verma, Mater Today Proc. 2022, 49, 217.
P. Li, X. Xia, J. Guo, Sep. Purif. Technol. 2022, 296, [eLocator: 121389].
F. Arshad, J. Lin, N. Manurkar, E. Fan, A. Ahmad, M. Tariq, F. Wu, R. Chen, L. Li, Resour. Conserv. Recycl. 2022, 180, [eLocator: 106164].
A. Bouter, X. Guichet, J. Clean. Prod. 2022, 344, [eLocator: 130994].
H. C. Kim, T. J. Wallington, R. Arsenault, C. Bae, S. Ahn, J. Lee, Environ. Sci. Technol. 2016, 50, 7715.
R. Faria, P. Marques, P. Moura, F. Freire, J. Delgado, A. T. de Almeida, Renew. Sustain. Energy Rev. 2013, 24, 271.
S. Rangaraju, L. De Vroey, M. Messagie, J. Mertens, J. Van Mierlo, Appl. Energy 2015, 148, 496.
D. Wang, N. Zamel, K. Jiao, Y. Zhou, S. Yu, Q. Du, Y. Yin, Energy 2013, 59, 402.
H. Hao, Z. Mu, S. Jiang, Z. Liu, F. Zhao, Sustainability 2017, 9, 504.
P. Marques, R. Garcia, L. Kulay, F. Freire, J. Clean. Prod. 2019, 229, 787.
S. Jenu, I. Deviatkin, A. Hentunen, M. Myllysilta, S. Viik, M. Pihlatie, J. Energy Storage 2020, 27, [eLocator: 101023].
T. Jiang, Y. Yu, A. Jahanger, D. Balsalobre‐Lorente, Sustain. Product. Consum. 2022, 31, 346.
H. S. Matthews, C. T. Hendrickson, C. L. Weber, Environ. Sci. Technol. 2008, 42, 5839.
B. Su, B. W. Ang, Appl. Energy 2015, 154, 13.
X. Lai, Q. Chen, X. Tang, Y. Zhou, F. Gao, Y. Guo, R. Bhagat, Y. Zheng, eTransportation 2022, 12, [eLocator: 100169].
T. Terlouw, C. Bauer, L. Rosa, M. Mazzotti, Energy Environ. Sci. 2021, 14, 1701.
S. Haefeli, P Bhatia, Non‐CO2 Greenhouse Gases: Scientific Understanding, Control Options and Policy Aspects, Vol. 1, IOS Press, Maastricht 2002.
B. Pankaj, C. L. Cynthia, R. David, L. Holly, B. Andrea, World Resources Inst. 2011.
J. Poschmann, V. Bach, M. Finkbeiner, J. Clean. Prod. 2023, 409, [eLocator: 137256].
L.‐B. Cui, Y. Fan, L. Zhu, Q.‐H. Bi, Appl. Energy 2014, 136, 1043.
L. Liu, C. Chen, Y. Zhao, E. Zhao, Renew. Sustain. Energy Rev. 2015, 49, 254.
W. Huang, Q. Wang, H. Li, H. Fan, Y. Qian, J. J. Klemeš, J. Clean. Prod. 2022, 349, [eLocator: 131480].
R. He, L. Luo, A. Shamsuddin, Q. Tang, Account. Finance 2022, 62, 261.
H. Hu, Y. Zhang, C. Yao, X. Guo, Z. Yang, Math. Biosci. Eng. 2022, 19, [eLocator: 11675].
L. Yao, MATEC Web Conf. 2016, 61, [eLocator: 04010].
H.‐L. Chang, C.‐M. Chen, C.‐H. Sun, H.‐D. Lin, IOP Conf. Series Mater. Sci. Eng. 2015, 87, [eLocator: 012016].
C.‐M. Chen, H.‐L. Chang, Sustainability 2022, 14, [eLocator: 4783].
N. G. Dlamini, K. Fujimura, E. Yamasue, H. Okumura, K. N. Ishihara, Int. J. Life Cycle Assess. 2011, 16, 410.
H. Muslemani, X. Liang, K. Kaesehage, F. Ascui, J. Wilson, J. Clean. Prod. 2021, 315, [eLocator: 128127].
I. C. Woertz, J. R. Benemann, N. Du, S. Unnasch, D. Mendola, B. G. Mitchell, T. J. Lundquist, Environ. Sci. Technol. 2014, 48, 6060.
J. Garcia, D. Millet, P. Tonnelier, S. Richet, R. Chenouard, J. Clean. Prod. 2017, 156, 406.
P. Javadi, B. Yeganeh, M. Abbasi, S. Alipourmohajer, Sustain. Product. Consump. 2021, 26, 316.
X. Tan, Z. Mu, S. Wang, H. Zhuang, L. Cheng, Y. Wang, B. Gu, Proc. Environ. Sci. 2011, 5, 167.
Y. Huang, H. Zhu, Z. Zhang, Sci. Total Environ. 2020, 727, [eLocator: 138578].
Q. Wang, Energy Data 2020, Green Development and Innovation Center, Beijing 2021.
Z. Meng, Y. Peng, J. Wu, X. Wu, K. Yan, B. Li, B. Zhang, Sustain. Energy Technol. Assess. 2023, 57, [eLocator: 103154].
IEA. CO2 Emissions in 2022, IEA, Paris 2023. https://www.iea.org/reports/co2-emissions-in-2022
F. Zhao, F. Liu, Z. Liu, H. Hao, J. Clean. Prod. 2019, 207, 702.
T. Peng, X. Ou, Z. Yuan, X. Yan, X. Zhang, Appl. Energy 2018, 222, 313.
L. A.‐W. Ellingsen, G. Majeau‐Bettez, B. Singh, A. K. Srivastava, L. O. Valøen, A. H. Strømman, J. Ind. Ecol. 2014, 18, 113.
S. Perdana, M. Vielle, Environ. Econ. Policy Stud. 2023, 25, 299.
M. A. Mehling, R. A. Ritz, Oxford Rev. Econ. Policy 2023, 39, 123.
F. Clora, W. Yu, E. Corong, Energy Policy 2023, 174, [eLocator: 113454].
J. de Santiago, H. Bernhoff, B. Ekergård, S. Eriksson, S. Ferhatovic, R. Waters, M. Leijon, IEEE Trans. Veh. Technol. 2012, 61, 475.
I. López, E. Ibarra, A. Matallana, J. Andreu, I. Kortabarria, Renew. Sustain. Energy Rev. 2019, 114, [eLocator: 109336].
C. Qiu, G. Wang, M. Meng, Y. Shen, Energy 2018, 149, 329.
K. Kawajiri, M. Kobayashi, K. Sakamoto, J. Clean. Prod. 2020, 253, [eLocator: 119805].
P. Stabile, F. Ballo, G. Mastinu, M. Gobbi, Energies 2021, 14, [eLocator: 766].
A. Giampieri, J. Ling‐Chin, Z. Ma, A. Smallbone, A. P. Roskilly, Appl. Energy 2020, 261, [eLocator: 114074].
N. Akafuah, S. Poozesh, A. Salaimeh, G. Patrick, K. Lawler, K. Saito, Coatings 2016, 6, [eLocator: 24].
H. J. Streitberger, K. F. Dössel, Automotive Paints and Coatings 2008. [DOI: https://dx.doi.org/10.1002/9783527622375.ch11]
L. Feng, L. Mears, C. Beaufort, J. Schulte, Energy Convers. Manage. 2016, 117, 454.
G. Sen, H.‐W. Chau, M. A. U. R. Tariq, N. Muttil, A. W. M. Ng, Sustainability 2022, 14, 222.
M. Philippot, G. Alvarez, E. Ayerbe, J. Van Mierlo, M. Messagie, Batteries 2019, 5, [eLocator: 23].
M. Mahmud, N. Huda, S. Farjana, C. Lang, Batteries 2019, 5, [eLocator: 22].
X. Sun, X. Luo, Z. Zhang, F. Meng, J. Yang, J. Clean. Prod. 2020, 273, [eLocator: 123006].
L. Wang, J. Hu, Y. Yu, K. Huang, Y. Hu, J. Clean. Prod. 2020, 276, [eLocator: 124244].
X. Lai, Y. Huang, H. Gu, C. Deng, X. Han, X. Feng, Y. Zheng, Energy Storage Mater. 2021, 40, 96.
X. Lai, Y. Huang, C. Deng, H. Gu, X. Han, Y. Zheng, M. Ouyang, Renew. Sustain. Energy Rev. 2021, 146, [eLocator: 111162].
N. Wang, A. Garg, S. Su, J. Mou, L. Gao, W. Li, Batteries 2022, 8, [eLocator: 96].
J. Quan, S. Zhao, D. Song, T. Wang, W. He, G. Li, Sci. Total Environ. 2022, 819, [eLocator: 153105].
E. Kallitsis, A. Korre, G. Kelsall, M. Kupfersberger, Z. Nie, J. Clean. Prod. 2020, 254, [eLocator: 120067].
M. A. Cusenza, S. Bobba, F. Ardente, M. Cellura, F. Di Persio, J. Clean. Prod. 2019, 215, [eLocator: 634].
J. C. Kelly, Q. Dai, M. Wang, Mitigat. Adapt. Strate. Glob. Change 2020, 25, 371.
H. Ambrose, A. Kendall, Transport. Res. Part D Trans. Environ. 2016, 47, 182.
S. Troy, A. Schreiber, T. Reppert, H. G. Gehrke, M. Finsterbusch, S. Uhlenbruck, P. Stenzel, Appl. Energy 2016, 169, 757.
Q. Dai, J. C. Kelly, in Electric, Hybrid, and Fuel Cell Vehicles (Ed: A. Elgowainy), Springer New York, New York, NY 2021, p. 395.
G. Majeau‐Bettez, T. R. Hawkins, A. H. Strømman, Environ. Sci. Technol. 2011, 45, [eLocator: 4548].
A. Accardo, G. Dotelli, M. L. Musa, E. Spessa, Appl. Sci. 2021, 11, 1160.
H. Wu, Y. Gong, Y. Yu, K. Huang, L. Wang, Environ. Sci. Pollut. Res. 2019, 26, [eLocator: 36538].
B. Ma, S. Yang, L. Zhang, W. Wang, S. Chen, X. Yang, H. Xie, H. Yu, H. Wang, X. Liu, J. Power Sources 2022, 548, [eLocator: 232030].
X. Xu, S. Tang, X. Han, L. Lu, Y. Wu, C. Yu, X. Sun, J. Xie, X. Feng, M. Ouyang, Reliabil. Eng. Syst. Safety 2023, 234, [eLocator: 109185].
L. Zhang, H. Yu, W. Wang, H. Xie, M. Wang, S. Yang, S. Chen, X. Liu, J. Energy Storage 2022, 55, [eLocator: 105473].
B. Jiang, J. Zhu, X. Wang, X. Wei, W. Shang, H. Dai, Appl. Energy 2022, 322, [eLocator: 119502].
R. Huang, X. Wang, B. Jiang, S. Chen, G. Zhang, J. Zhu, X. Wei, H. Dai, J. Power Sources 2023, 566, [eLocator: 232929].
R. Xiong, J. Huang, Y. Duan, W. Shen, Appl. Energy 2022, 314, [eLocator: 118915].
S. Yang, R. He, Z. Zhang, Y. Cao, X. Gao, X. Liu, Matter 2020, 3, 27.
B. Ma, H. Q. Yu, L. H. Yang, Q. Liu, H. C. Xie, S. Y. Chen, Z. J. Zhang, C. Zhang, L. S. Zhang, W. T. Wang, X. H. Liu, Rare Met. 2023, 42, 368.
B. Ma, H. Yu, W. Wang, X. Yang, L. Zhang, H. Xie, C. Zhang, S. Chen, X. Liu, Rare Met. 2023, 42, 885.
J. Jiang, H. Ruan, B. Sun, L. Wang, W. Gao, W. Zhang, Appl. Energy 2018, 230, 257.
Z. Gao, H. Xie, X. Yang, W. Niu, S. Li, S. Chen, Batteries 2022, 8, [eLocator: 234].
L. Zhang, S. Chen, W. Wang, H. Yu, H. Xie, H. Wang, S. Yang, C. Zhang, X. Liu, J. Energy Chem. 2022, 75, 408.
S. Chen, Z. Gao, T. Sun, Energy Sci. Eng. 2021, 9, 1647.
L. Zhang, W. Fan, Z. Wang, W. Li, D. U. Sauer, J. Energy Storage 2020, 32, [eLocator: 101885].
R. Xiong, Z. Li, R. Yang, W. Shen, S. Ma, F. Sun, Appl. Energy 2022, 324, [eLocator: 119762].
S. R. Revankar, V. N. Kalkhambkar, J. Energy Storage 2021, 41, [eLocator: 102937].
Q. Yu, L. Dai, R. Xiong, Z. Chen, X. Zhang, W. Shen, Appl. Energy 2022, 310, [eLocator: 118588].
Y. Hua, S. Zhou, Y. Huang, X. Liu, H. Ling, X. Zhou, C. Zhang, S. Yang, J. Power Sources 2020, 478, [eLocator: 228753].
Y.‐H. Chiang, W.‐Y. Sean, C.‐H. Wu, C.‐Y. Huang, J. Clean. Prod. 2017, 156, 750.
S. Tong, T. Fung, M. P. Klein, D. A. Weisbach, J. W. Park, J. Energy Storage 2017, 11, 200.
K. Richa, C. W. Babbitt, N. G. Nenadic, G. Gaustad, Int. J. Life Cycle Assess. 2017, 22, 66.
C. Ioakimidis, A. Murillo‐Marrodán, A. Bagheri, D. Thomas, K. Genikomsakis, Sustainability 2019, 11, [eLocator: 2527].
N. Wilson, E. Meiklejohn, B. Overton, F. Robinson, S. H. Farjana, W. Li, J. Staines, Resour., Conserv. Recycl. 2021, 174, [eLocator: 105759].
Y. Hua, X. Liu, S. Zhou, Y. Huang, H. Ling, S. Yang, Resour. Conserv. Recycl. 2021, 168, [eLocator: 105249].
A. Barré, B. Deguilhem, S. Grolleau, M. Gérard, F. Suard, D. Riu, J. Power Sources 2013, 241, 680.
J. Huang, L. Albero Blanquer, J. Bonefacino, E. R. Logan, D. Alves Dalla Corte, C. Delacourt, B. M. Gallant, S. T. Boles, J. R. Dahn, H. Y. Tam, J. M. Tarascon, Nat. Energy 2020, 5, 674.
J. Huang, S. T. Boles, J.‐M. Tarascon, Nat. Sustain. 2022, 5, 194.
M. Alfaro‐Algaba, F. J. Ramirez, Resour., Conserv. Recycl., 2020, 154, [eLocator: 104461].
Y. Tao, C. D. Rahn, L. A. Archer, F. You, Sci. Adv. 2021, 7, [eLocator: eabi7633].
A. Kumar, A. Gupta, S. Verma, A. R. Paul, A. Jain, N. Haque, in Life Cycle Assessment Based Environmental Footprint of a Battery Recycling Process, Springer Singapore, Singapore 2022, p. 115.
J. Yang, F. Gu, J. Guo, Resour., Conserv. Recycl. 2020, 156, [eLocator: 104713].
M. Mohr, J. F. Peters, M. Baumann, M. Weil, J. Ind. Ecol. 2020, 24, [eLocator: 1310].
M. Yu, B. Bai, S. Xiong, X. Liao, J. Clean. Prod. 2021, 321, [eLocator: 128935].
R. E. Ciez, J. F. Whitacre, Nat. Sustain. 2019, 2, 148.
L. Kurz, M. Faryadras, I. Klugius, F. Reichert, A. Scheibe, M. Schmidt, R. Wörner, Batteries 2021, 7, [eLocator: 29].
C. J. Rydh, M. Karlström, Resour., Conserv. Recycl. 2002, 34, 289.
You have requested "on-the-fly" machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Show full disclaimer
Neither ProQuest nor its licensors make any representations or warranties with respect to the translations. The translations are automatically generated "AS IS" and "AS AVAILABLE" and are not retained in our systems. PROQUEST AND ITS LICENSORS SPECIFICALLY DISCLAIM ANY AND ALL EXPRESS OR IMPLIED WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES FOR AVAILABILITY, ACCURACY, TIMELINESS, COMPLETENESS, NON-INFRINGMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Your use of the translations is subject to all use restrictions contained in your Electronic Products License Agreement and by using the translation functionality you agree to forgo any and all claims against ProQuest or its licensors for your use of the translation functionality and any output derived there from. Hide full disclaimer
© 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the "License"). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.
Abstract
Under the global carbon neutrality initiative, carbon emissions from the transportation sector are becoming increasingly prominent due to the growth in vehicle ownership. And electric mobility may be a potentially effective measure to reduce road traffic carbon emissions and achieve a green transformation of transportation. This paper systematically collates the relevant carbon accounting standards for the automotive industry and elaborates the current status of road transport greenhouse gas emissions by combining the data from the International Energy Agency. And by comparing the lifecycle carbon footprint of various energy types of vehicles, the necessity and feasibility of electric mobility to reduce carbon emissions are discussed. However, the comparison of vehicle lifecycle carbon footprints shows that electric vehicles (EVs) are not as environmentally friendly as expected, although they can significantly reduce road traffic carbon emissions. The high carbon emissions from the manufacturing process of the core components of EVs, especially the power battery, reduce the low‐carbon potential of electric mobility. Therefore, the carbon emission reduction strategies and outcomes of automakers in the automotive industry chain have been further reviewed. Finally, focusing on vehicle power batteries, this article reviews the technologies such as refined management and echelon utilization that can make EVs more environmentally friendly and promote carbon neutrality in the transportation sector.
You have requested "on-the-fly" machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Show full disclaimer
Neither ProQuest nor its licensors make any representations or warranties with respect to the translations. The translations are automatically generated "AS IS" and "AS AVAILABLE" and are not retained in our systems. PROQUEST AND ITS LICENSORS SPECIFICALLY DISCLAIM ANY AND ALL EXPRESS OR IMPLIED WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES FOR AVAILABILITY, ACCURACY, TIMELINESS, COMPLETENESS, NON-INFRINGMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Your use of the translations is subject to all use restrictions contained in your Electronic Products License Agreement and by using the translation functionality you agree to forgo any and all claims against ProQuest or its licensors for your use of the translation functionality and any output derived there from. Hide full disclaimer
Details
1 State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun, China
2 College of Automotive Engineering, Jilin University, Changchun, China
3 School of Transportation Science and Engineering, Beihang University, Beijing, China
4 State Grid Jilin Electric Power Company Limited, Changchun, China