Weilan New Energy Li Yongwei: mixed solid-liquid solid-state batteries will be loaded in bulk

"in the automotive field, we have an energy density of 270 Whhand kg, and high-safety vehicle hybrid solid-liquid solid-state power batteries that can be punched by acupuncture have entered SOP, to realize batch loading, and are promoting the research and development and engineering of solid-state power batteries with higher energy density as planned, and batch verification will be provided to customers in the second half of next year."

Li Yongwei, deputy general manager of Beijing Weilan New Energy Technology Co., Ltd., made a report on the progress of the research and development of hybrid solid-liquid solid-state batteries at the 2021 China International Lithium Industry Conference held at the Shanghai Automotive Convention and Exhibition Center on July 7. said in an interview with the media.

At present, Weilan New Energy is building a large-scale 2GWh solid-liquid hybrid solid power battery production line, which mainly produces 350-360Wh/kg new energy vehicle power batteries.

From the perspective of the whole industry, Weilan New Energy is the first batch of enterprises to achieve mass production of solid-state batteries. As early as last August, Weilan New Energy established a 200 million watt-hour hybrid solid-liquid solid-state power battery demonstration production line at the solid-state battery industry demonstration base in Liyang, Jiangsu Province. The energy density of the solid-state battery can reach 270 Whshock / kg, the rate performance can achieve 3C continuous Discharge, and the maximum Discharge rate can reach 7C, while maintaining a good safety performance. At present, this product has taken the lead in large-scale applications in industrial UAV and special fields.

According to reports, Weilan New Energy's current scale of mass production of mixed solid-liquid solid-state batteries, in the positive and negative material system, is not much different from the current liquid batteries. It is mainly based on such material systems as modified high nickel ternary, silicon-based anode materials plus solid electrolytes, ionic conductive films and so on. However, the company's R & D team has made many improvements to the needs of solid-state battery products on the basis of the existing material system.

In the aspect of cathode materials, the improved way is mainly to modify the surface, which can solve the problem of compatibility with solid electrolytes, restrain oxygen evolution at high temperature and improve the stability of the materials, so as to improve the safety of the cathode side. In addition, at the negative electrode level, many improvements have been made in solid electrolytes.

"from the perspective of solid-liquid mixing ratio, the weight percentage of electrolyte content of conventional liquid batteries is about 20% Mel 25%. The liquid content of Weilan's current products can reach about 10%, and will gradually drop to less than 3-5%, or even 1-2% in the future." Li Yongwei introduced.

The hybrid solid-liquid solid-state battery technology of Weilan new energy can achieve the role of wetting interface with a small amount of liquid and maintain a good ion transport channel. With less and less liquid, the relative safety will be greatly improved. At the same time, the safety of the battery can be further improved through the introduction of solid electrolyte.

According to reports, the manufacturing process and equipment of Weilan new energy hybrid solid-liquid solid-state battery are not much different from the current liquid battery process and equipment, basically more than 90% are the same. But in the key process, such as mixing, because of the addition of solid electrolyte, the equipment will be different; in addition, in the liquid injection and in-situ solid state, the mode of operation is not the same as the current liquid battery. "although it is similar equipment, but in the specific equipment customization, we will have special process requirements." Li Yongwei said.

In terms of packaging form, Weilan hybrid solid-liquid solid-state battery is mainly in the form of soft package, while square battery and cylindrical battery are also being developed by teams, according to the different performance requirements such as energy density, safety, cycle life and so on. as well as the application scene is different, adopt the corresponding suitable product form.

"our idea is to develop a suitable battery for an application scenario based on the solid-state battery technology platform." Li Yongwei said that Weilan is currently developing hybrid solid-liquid batteries, including 350Wh/kg and 400Wh/kg batteries with energy density, so that they can adapt to different application scenarios and meet the needs of different customers.

On the issue of the cost of hybrid solid-liquid batteries, Li Yongwei said that the recent increase in the price of raw materials for batteries is closely related to the large-scale expansion of production by power battery manufacturers, and before the production capacity of raw materials does not follow up quickly, there will be price fluctuations. In the future, new energy vehicles and power batteries will reach trillions of industries, and the main body of the industry will return to a more rational state, then materials will also return to normal. At the same time, with the improvement of battery energy density in the future, the reduction of battery comprehensive cost brought by technological progress will be very obvious.

According to reports, solid-state batteries have a variety of technical routes, but in the end they all have the same goal. Li Yongwei pointed out that in fact, one of the goals of solid-state batteries, especially all-solid-state batteries, is to import metal lithium negative electrodes or composite lithium negative electrodes with high specific capacity, so that the specific capacity of the negative electrodes will be greatly improved. on the whole, the energy density of the battery will also be greatly improved.

"in order to achieve high energy density of 500Wh/kg and 600Wh/kg, it is necessary to introduce lithium composite anode with high safety and long life from the point of view of functionalization." Li Yongwei further said.

Based on the development of the industry and the technical planning of Weilan New Energy, Li Yongwei believes that all-solid-state batteries will be introduced into the market around 2025-2026, but the early stage will not introduce large-capacity, high-rate power batteries for power or energy storage.

He believes that the first to introduce will be the solid state battery in the special application field, whose capacity is not very large, and the rate and cycle requirements are not particularly high. Through the introduction of first-level products, problems are found to be constantly improved and the comprehensive performance is improved. Finally, it will be extended to the field of energy storage and new energy vehicles.