BYD has won three solid-state battery patents in a row

The solid-state battery layout of large manufacturers often starts with patents. Qidian Solid-State Battery learned that BYD recently disclosed three solid-state battery patents.
The first patent is called all-solid-state battery, battery pack and power-consuming equipment, with the authorization announcement number CN 118748295 B and the application date of August 2024. However, the detailed information of the patent was not disclosed.
The second patent is called composite binder, electrode slurry, electrode pole piece and all-solid-state battery, with the patent application number CN 202210903859.8 and the authorization date of December 10, 2024. The principle of this patent is to introduce the complementary use of rigid binder and flexible binder with low oxygen-containing groups, enhance the solubility of composite binder in solvent, effectively improve the viscosity of composite binder and the stability of sulfide solid electrolyte, enhance the adhesion between inorganic particles in slurry and between particles and current collector, and improve the first cycle efficiency of battery.
The third patent is named composite silicon-based negative electrode material, negative electrode sheet and all-solid-state lithium battery. The patent application number is CN 202110305173.4, and the authorization date is December 10, 2024. This patent provides a newly developed silicon-based negative electrode material, the core of which is a lithium-silicon alloy, the first coating layer has Li3N and Li3P substances, and the second coating layer is an amorphous lithium-silicon alloy. The negative electrode material has good electrical conductivity. In addition, this patent also provides a negative electrode sheet and an all-solid-state lithium battery using the composite silicon-based negative electrode material.
It is worth mentioning that BYD has obtained 3,659 new patents this year, an increase of about 16% year-on-year; this year’s H1 R&D investment is about 19.6 billion yuan, an increase of about 41.8% year-on-year. In addition to BYD, FAW and Honeycomb Energy have also recently disclosed patent information. FAW’s patent application is named: a composite solid electrolyte film and its preparation method and application. The principle of this patent is to fill the lithium polymer with an oxide solid electrolyte doped with inorganic fillers, obtain a three-dimensional composite support membrane skeleton by electrospinning, and compound the halide solid electrolyte by solution immersion method to form an integrated organic/inorganic composite solid electrolyte structure. The name of the Honeycomb Energy patent is: a sulfide electrolyte and its preparation method and solid-state battery. It effectively improves the high ionic conductivity and air stability of the sulfide solid electrolyte and broadens the electrochemical window.
01 BYD: Solid-state batteries are good, but they take time.
Like CATL, BYD is “pushed” by the solid-state battery trend and passively accelerates the update of its solid-state battery technology progress. The two lithium battery giants are full of awe for this new technology. As the market environment changes, they have to speed up the research and development. It is reported that BYD waded into solid-state battery research and development around 2016. In 2022, it was reported that BYD’s all-solid-state lithium battery started loading tests in Chongqing. The project was led by Academician Ouyang Minggao, and three academician consultants participated in the research and development work. The energy density of the negative electrode using silicon-based materials is twice that of the blade battery. The first model may be the Yangwang series, which will also be supplied externally. For a whole year after the revelation, BYD remained silent in the field of solid-state batteries. Until the middle of this year, Fudi Battery updated the relevant information about solid-state batteries, and BYD executives also successively expressed their views on the future of solid-state batteries. BYD’s solid-state battery technology route is: high-nickel ternary positive electrode/sulfide solid electrolyte, the negative electrode has not been disclosed yet, but from the patent point of view, both silicon-based and metallic lithium are available, using Ni88 ternary material, the liquid specific gravity is less than 10%, and the energy density is 300Wh/Kg. After analyzing from the perspective of end consumers, Fudi Battery believes that the silicon-based negative electrode + sulfide route has balanced performance and great commercialization potential. However, in terms of technical route selection, the halide composite electrolyte route may also be adopted. The cell capacity is planned to be above 60Ah, and the cost will be controlled to the greatest extent. The cost is planned to be reduced by 15 to 20 times by 2027 compared with 2024, and by 30% to 50% by 2030 compared with 2027, and by another 20% to 30% by 2033. The mass production time is also expected to be small-scale production in 2027, first equipped with high-end models for trial, and then further promoted in 2030, so that the market share will gradually increase. In September this year, BYD Chief Scientist Lian Yubo said in public that although BYD has been deeply involved in the field of solid-state batteries, it will take 3 to 5 years for solid-state batteries to be commercialized on a large scale, and lithium iron phosphate batteries will not be eliminated in the next 15 to 20 years, but solid-state batteries and liquid batteries will gradually make the price of cars different. Following the previous foot, BYD Battery CTO Sun Huajun also said that the actual state of BYD’s solid-state battery is still in the process of transformation from early laboratory to engineering. At present, a large amount of laboratory data has been mastered and many samples have been made, but the pain points have not been solved. There are still problems to be overcome in mass production, such as engineering problems and interface problems. There is still a long way to go for large-scale mass production of all-solid-state batteries. In addition to self-research, BYD is also actively seeking external cooperation. For example, in November this year, Shenzhen Advanced Institute and BYD signed a cooperation agreement on forward-looking technology projects for new energy vehicles. The two parties will focus on solid-state batteries, lithium battery auxiliary materials and other fields for joint technical research.
02 China, Japan, South Korea and the United States are working together
The patent war for solid-state batteries has intensified. Since November this year, there has been an increase in news related to solid-state battery patents. On November 5, the State Intellectual Property Office announced three solid-state battery patents of CATL; on the same day, Huawei also announced a sulfide solid-state battery invention patent. As a key link in the new energy vehicle industry chain, battery technology directly affects the quality of vehicles. Whoever gets the holy grail of solid-state batteries first will take the initiative in the next round of scientific and technological revolution. Patent layout is the first step. Japan was the first country to apply for large-scale patents in the field of solid-state batteries. In the past two years, China’s patents in the field of solid-state batteries have grown rapidly and has become one of the world’s major sources of technology. The key technologies of solid-state batteries include electrolyte materials, positive and negative electrodes, electrolyte membranes, and preparation processes. Among them, electrolyte-related patents account for the largest proportion and are the hot spot for solid-state battery patent layout. How to maximize the three technical routes of polymers, oxides, and sulfides has become the top priority for major battery factories/new energy vehicle companies/research institutions. In terms of electrolyte technical routes, the sulfide technical route is the focus of Japanese/South Korean companies, while my country is the country with the most sources of polymer electrolyte technology. The oxide patent field is a blue ocean, and research institutions in various countries have opportunities. It is worth noting that with the technological breakthrough of halide electrolytes, Panasonic’s research focus has begun to shift to halide and oxide technical routes, such as oxide LiMOX and halide LiMX. To this end, Panasonic Group has carried out a series of patent layouts and gradually built a patent barrier.