The development of new energy vehicles is a systematic project, encompassing many aspects such as the forward development of the entire vehicle, core technologies for electric drive, battery, and electronic control systems, lightweighting, and intelligentization. However, the most fundamental and crucial element is the breakthrough in battery technology, which is the key to solving many problems related to range anxiety, high costs, and performance improvements in electric vehicles. Therefore, the battery industry should be at the forefront of innovation within the entire new energy vehicle industry. The extent of progress in the research and development and implementation of power battery cells, as well as process research, over the next five years, until around 2023, warrants careful examination.
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"In-Depth Analysis and Inquiry" is Autohome's first column designed for industry users. It features articles by seasoned automotive industry professionals, providing exclusive analysis and insights into major industry events. Beyond the surface excitement, we aim to present you with an exploration and reflection on the essence, cause and effect, and future possibilities of these events.
This issue's industry commentator, Zhu Yulong, is a technical engineer with many years of experience in the fields of automotive electronics and new energy vehicles. He has worked for well-known OEMs and parts companies such as SAIC-GM, LEAR, and Jiexin Power, and has a deep understanding of automotive technology innovation and development, and is full of enthusiasm for exploration.
A quick 1-minute overview of the full text:
●my country's power lithium-ion battery market used to adhere to the lithium iron phosphate route for a long time, but has now generally shifted to the research and development and production of ternary lithium batteries.
Looking ahead to the next five years, high-nickel ternary cathodes combined with silicon-carbon anodes are the most feasible way to improve specific energy (range).
● Solid-state batteries will not be used in the short term, but mass production and application are expected to begin in 2025.
● Battery technology sees some gradual improvements every year, but the pace of innovation may not be as fast as expected.
I. Innovation in Power Lithium-ion Battery Cell Technology
Since the promotion and demonstration of new energy vehicles in my country, lithium iron phosphate batteries have gradually taken the lead, becoming popular from around 2010 to 2015, while ternary lithium batteries have risen to prominence. In the new energy vehicle market in 2015, the market share of ternary lithium and lithium iron phosphate batteries was 30/70; in 2016 it was 40/60; in 2017 it was almost even; and in the first half of 2018, ternary lithium batteries began to overtake them.
The shift from lithium iron phosphate to ternary lithium batteries in the power lithium-ion battery market was not instantaneous. As shown in the diagram, before the rapid conversion in China, foreign battery companies had already made some changes to the cell chemistry system. The reason it seemed to happen "suddenly" is mainly because we persisted with the lithium iron phosphate route for a relatively long time. When the shift to ternary lithium battery cell development became widespread after 2016, we suddenly caught up with the technological path of Japan and South Korea.
Evolution of Cell Chemistry System Paths in Typical Foreign Companies
Currently, the ternary lithium-ion battery system used in China is lithium nickel cobalt manganese oxide (NCM). Nickel is used to improve the energy density of materials. Based on the different proportions of the three transition metal ions, materials are divided into low-nickel NCM424, NCM333, and NCM523, and high-nickel NCM622 and NCM811. The industrialization process has mainly progressed from low-nickel NCM333 and 523 to high-nickel 622 and 811.
Regarding the entire vehicle, there are four key issues that need to be addressed in the development of power lithium-ion batteries:
● Battery cell price: As subsidies for new energy vehicles continue to be phased out, battery prices will continue to decline in the future. In stages, at the beginning of 2021, the price of battery cells will drop to 0.7 yuan/Wh, about 100 US dollars/kWh; by 2023, it will further decrease to 0.6 yuan/Wh, about 80 US dollars/kWh.
●Cell lifespan: The lifespan of the existing NCM523 system is about 8 to 10 years. It wears out faster with heavy use. The goal is to extend the lifespan to 10 years.
● Cell safety: To improve cell safety, the approach is to gradually optimize key factors such as electrolyte formulation and separator, and to establish a more fundamental safety mechanism.
● Cell energy density: Subsidy policies set new benchmarks for battery energy density every year, and the country has also set the "Medium and Long-Term Development Plan for the Automobile Industry" to achieve a single-cell energy density of 300Wh/kg by 2020.
We will focus on the impact of battery specific energy on the development of electric vehicles. Currently, major pure electric vehicle platform plans can be divided into the following tiers. Battery capacity generally starts at 40kWh. Simply adding more batteries is not enough to achieve longer driving range; the batteries themselves are large and heavy, and stacking more of them actually leads to reduced energy consumption and decreased driving range.
Currently, mainstream battery system energy densities range from 140kWh/kg to 160kWh/kg, with driving ranges generally reaching 350-400km. Domestic plans for high-end electric vehicles aim to increase the driving range to 500km around 2020 through optimized cell design. Currently, international platforms like Volkswagen's MEB platform, BMW's iNext series, and Mercedes-Benz's EQ series all plan for different energy densities, selecting these by controlling the total battery capacity.
Looking at the progress of mainstream battery manufacturers, product iteration speeds can be divided into aggressive and moderate approaches, both aiming to comprehensively consider improving energy density while meeting safety, lifespan, and other performance indicators. For manufacturing batteries of the same size, a higher watt-hour count results in a lower manufacturing cost per watt-hour. Due to environmental control requirements at the manufacturing level, there is also a process of production line modification in the short term.
『Domestic and International Mainstream Battery Cell Energy Density Improvement Strategies』
Currently, cylindrical power lithium-ion batteries have achieved mass production of high-nickel products first, and breakthroughs in prismatic and pouch batteries are imminent. It is expected that the industry will see a widespread breakthrough in the mass production of high-nickel products in 2019. Before breakthroughs in other types of power technologies, the life cycle of high-nickel ternary cathode products is expected to be at least five years.
II. How far away is the application of solid-state batteries?
Feedback from major battery suppliers suggests that while cell-level technology development may accelerate rapidly over the next five years, the pace of practical application iterations to meet vehicle requirements is not as fast as we might imagine. Therefore, some automakers are already experimenting with solid-state batteries as a leapfrog approach to solving the problem.
Recently, Volkswagen announced an investment of approximately $100 million in QuantumScape, aiming to develop and mass-produce solid-state batteries by 2025. Volkswagen has been interested in QuantumScape for many years, acquiring a 5% stake in the company in December 2014. This $100 million investment represents a new investment, indicating Volkswagen's confidence in the technology's feasibility. In Japan, the Japanese government, Japanese battery manufacturers, and the three major automakers—Honda, Nissan, and Toyota—are jointly developing solid-state lithium-ion batteries. However, based on statements from several industry leaders, the timeline is expected to be after 2025.
In an interview, Takao Asami, Senior Vice President of Research and Advanced Engineering at Nissan, stated that solid-state battery technology will not be ready for use in electric vehicles until 2025. Obstacles include cost and production difficulties, and the technology is currently still largely in the initial research stage. Toyota Chairman Takeshi Uchiyamada also stated, "We are working hard on this research, but there are still some issues to resolve if we want to achieve large-scale mass production." This illustrates that solid-state battery development requires collaboration between internal and external innovative companies, and it cannot be readily applied in the short term.
Automakers face many practical challenges in investing in solid-state batteries, including cost and manufacturing processes.
Summarize:
Looking at it calmly, while the technology of power lithium-ion battery cells has seen gradual improvements each year over the past five years, the pace of innovation at the cell level may not be as fast as expected to support the rapid popularization of electric vehicles. Overall, achieving the 300Wh/kg target by 2020 is achievable. The question is, does achieving this target mean it can be used in electric vehicles? The answer is uncertain. Automotive power lithium-ion batteries are a complex system engineering project; meeting the specific energy requirement is only one condition. Other performance aspects (charge/discharge rate, power, lifespan, safety, etc.) are also crucial. Beyond achieving high specific energy, comprehensively developing and improving other performance indicators requires a significant investment of time and effort.
