Is solid-state lithium battery the next-generation EV batteries
Solid-state battery advantages
The report shows that there are 3,033 reports of new energy vehicle defect clues, reflecting that “power battery overheating and fire” and “electronic control system failure” still account for a large proportion, which are the primary safety hazards of new energy vehicles.
The main cause of fire in lithium batteries is the electrolyte. The electrolyte is very sensitive to temperature. It is easily decomposed at high temperature, highly corrosive, flammable and easy to leak. Especially the lithium evolution reaction can easily cause a short circuit.
In comparison, the most prominent advantage of solid-state batteries is safety. It uses an almost non-flammable solid electrolyte as a conductive medium, which reduces the sensitivity of the battery pack to temperature, and effectively blocks the positive and negative electrodes with good insulation.
In addition to the natural advantages of safety, another major aspect of solid-state batteries is performance.
New energy vehicles have been developing towards the path of high endurance, and to achieve this goal, lithium batteries with higher energy density are required. Under the inherent bottleneck of liquid lithium battery technology, it is difficult to achieve future energy density goals. From the perspective of the future high energy density technology development path of lithium batteries, solid-state batteries are undoubtedly more suitable for large-scale applications.
The use of solid electrolytes can change the existing positive and negative electrode systems, and use higher specific capacity materials as positive and negative electrodes. By using lithium metal in the negative electrode and high potential material in the positive electrode, the electrochemical window can reach more than 5V. The specific capacity of lithium is as high as 3860 mA h/g, which is more than 10 times that of graphite and 17.5 times that of ternary high nickel cathodes.
Currently in use, or close to commercial solid-state battery electrolytes, there are three kinds of polymers, sulfides and oxides. Recently, the University of Science and Technology of China synthesized a new solid-state electrolyte, lithium zirconium chloride, which reduced the cost by 94%.
Safety, performance and cost are the three core elements of lithium battery promotion. In these three aspects, solid-state batteries have shown great advantages. There is no doubt that the mainstream technology path of lithium batteries in the future belongs to solid-state batteries.
At present, solid-state battery technology is still in a blue ocean. Electrolyte, cathode and other materials have not appeared subversive alternative products, and have not formed an industrial foundation. This is the best time for first movers to gain an advantage.
However, how to identify solid stated battery companies with development prospects and potential is a difficult problem for investors.
Pouch packaging method
Traditional lithium battery and solid-state battery packaging has three processes: pouch, square and cylindrical. The pouch battery produced by the lamination process has a low probability of internal deformation, bending or breaking.
In addition, the aluminum-plastic film casing of the pouch battery is not hard. Once the battery is thermally out of control, the flatulence will generally break through the aluminum-plastic film package first, taking away a lot of heat and preventing the battery from exploding.
The lighter aluminum-plastic film shell, under the same capacity, makes the whole battery 40% lighter than the steel shell lithium battery and 20% lighter than the aluminum shell lithium battery. Therefore, the energy density of the pouch battery will be 40% higher than that of the steel shell ternary lithium battery.
Pouch batteries have won the favor of downstream car manufacturers, and car companies such as Volkswagen and Mercedes-Benz have used them to configure a variety of mainstream models. The pouch battery companies represented by Farasis Technology have been working hard for many years, and the product quality has reached the international advanced level, and has successfully entered the Daimler A supply system.
In 2021, Farasis Technology in Top 10 power battery manufacturers in China. In terms of installed capacity of pouch batteries and ternary pouch batteries in China, Farasis maintained the first place continuously.
Conclusion
In the advancement of solid-state battery technology, from the government to the enterprise, no effort is spared.
Automobile groups including BMW, Mercedes-Benz, Volkswagen, etc. all take solid-state lithium batteries as the technical direction of their next-generation electric vehicle batteries. At the government level, EU countries jointly invested 3.2 billion euros and raised 5 billion euros from private investors for the development of solid-state batteries.
The United States, Japan, and South Korea have also announced support policies and subsidies for the development of solid-state lithium batteries.
China has put forward requirements to strengthen the research and development and industrialization of solid-state batteries. The first batch of 50 Dongfeng-Ganfeng high specific energy solid-state battery vehicles jointly developed by Dongfeng Motor and Ganfeng Lithium were delivered in Xinyu City, Jiangxi Province.
In this context, the certainty of the future of solid-state batteries is beyond doubt, and it has even begun to speed up.
