▲The picture shows Wang Qiang, CTO of Teamgiant new energy and President of the Research Institute
On October 16, "the Fifth International Summit on power battery application (cbis2020) and the first China new energy and new materials (Ningde) summit" was held in Ningde, Fujian Province. This summit is jointly sponsored by China chemical and physical power industry association, people's Government of Ningde City, Fujian Province, China battery network, Ningde times, National Engineering Research Center of electrochemical energy storage technology and 21C innovation laboratory. At the theme forum of "Application of advanced materials and new technologies", CTO of Teamgiant new energy and Wang Qiang, President of the Research Institute, shared the ideas and achievements of Teamgiant new energy in the research and development of solid state battery technology based on soft package technology.
Wang Qiang said that there are some common problems with solid-state batteries: the first is the low ionic conductivity of solid-state electrolyte; the second is the lack of visible and quantitative means of solid-state interface; the third is that the whole manufacturing process of solid-state batteries has a little more subversion on the industry, so is there a simpler and more mature way to do this.
According to Wang Qiang, Teamgiant new energy mainly focuses on the soft package power technology route which is popular among the international mainstream passenger cars. "Relatively speaking, the basic conditions of soft pack battery in solid-state battery are better than that of square or cylindrical battery.". "The industry hopes that the way to increase the battery energy density to 400wh / kg ~ 500wh / kg will be realized by solid-state batteries," Wang Qiang believes. Considering the current development and reserve of material technology, it is hoped that the initial mass production of solid-state batteries from 300wh / kg to 350wh / kg will be achieved in the next two to three years.
According to Wang Qiang, Teamgiant new energy is based on the basic research and accumulation of soft package and solid state. In the research and development idea of solid-state battery, the electrolyte adopts polymer solid electrolyte, which is different from the traditional sulfide or oxide solid electrolyte. "The idea of in-situ polymerization and precise solidification of electrolyte is better compatible with the existing power production line process, which is the basic idea to realize at present." Wang Qiang also revealed that the positive electrode will use high nickel and the negative electrode will use silicon oxygen.
In Wang Qiang's view, the industrialization of polymer solid-state battery is expected to accelerate in recent years, "because the first way it adopts is small molecules, the second is ionic liquid, and the third is plasticizer. There are many ways to realize it." Wang Qiang said that Guangdong Teamgiant's current solution is through in-situ polymerization. At the soft package level, the solution of precursor is added and the polymerization is initiated by heat. "The adjustment range of the whole production line, including the whole operation mode, is very small compared with the existing soft package process."
The safety of power battery is a widespread concern in the industry and society. At present, there are many ways to prevent thermal runaway through the multi-dimensional design of pack. Can we improve the internal factors of thermal runaway from the inside of the battery cell? According to Wang Qiang, Teamgiant new energy has also made a lot of innovations in this area. For example, in the manufacturing of the cell, we have made many attempts through the coating process and polymerization process. The designed cell products have the function of endogenous prevention of thermal runaway, and have the feasibility of planned mass production. "At present, many parameters are still being optimized," according to Wang Qiang, the company is still in the equipment link For example, the equipment developed together with scientific research institutes mainly solves how to deal with in-situ characterization stress during the contact process between electrode and electrolyte of solid-state battery or semi-solid battery.
According to Wang Qiang, at present, the energy density of the company's first solid-state battery sample is about 277wh / kg, and there is still room for optimization of the overall cycle life; the energy density of the second solid-state battery sample is about 302wh / kg, and the negative electrode uses silicon oxygen and graphite, so the cycle performance is not particularly excellent, mainly because the current solid-state electrolyte introduction still needs to be improved.
In pack level, CTP and blade technology have appeared in square battery in recent two years. However, it is difficult to realize CTP for soft package battery. However, Wang Qiang disclosed that Teamgiant new energy has also made innovations in the structure and process optimization of the soft package pack. "At present, the soft package battery pack is to increase the charging capacity of single module and increase the capacity of the whole battery pack by enlarging the modules and reducing the number of modules and related structural parts in the pack."
Since this year, LiFePO4 has recovered in the new energy passenger vehicle market, and some voices in the industry have begun to argue about the route of Sanyuan and LiFePO4. Wang Qiang believes that battery technology will continue to improve, and it is expected that there will be a big breakthrough in the safety of ternary batteries in the next 1 to 2 years. "Lithium iron phosphate is indeed a good choice for many application models, but from the perspective of technology development trend, the technology of ternary battery still needs the concerted efforts of the industry."
(Note: the article is reprinted from China battery network)
