Recently, Mr. Chen Henglong, Chairman of Suzhou Yimao Electric Bus Co., Ltd. and Dr. Chen Henglong from the University of Delaware, USA, delivered a speech entitled “Overview of Mainstream Technical Features of Power Lithium Batteries” at the “Power Battery Exchange Conference”. The following are the main contents of Chen Henglong's speech:
The government's strong support for electric vehicles has given birth to the rapid development of power lithium batteries and the rapid expansion of production capacity. In 2014, the power lithium battery passed the low-speed market cultivation period and ushered in the first market peak. In 2015, the power lithium battery went up all the way, and there was a shortage of goods in short supply in the second half of the year. At the same time, capital began to flow into this field in a large amount, and there was a large expansion of production capacity.
In 2015, the company sold 380,000 new energy vehicles. At the same time, some car companies were seriously defrauded. The state ordered the four ministries to form a joint investigation team to investigate, clean up, rectify, punish and standardize. This fraudulent incident prompted the government to re-regulate the new energy vehicle support policy. This process lasted for half a year, and the relevant policies have become clearer and have affected sales in 2016.
At the same time, in order to ensure the safety of electric vehicles, the state banned the subsidies used by ternary lithium material batteries in public transportation and related commercial vehicles, and invisibly proposed a focus of battery materials on EVs. In the development of new energy vehicles, various technical debates and focuses have been accompanied by every stage of industrial development. The discussion and evaluation of various technologies are often accompanied by stormy waves.
Electric vehicle technology: China's pure electric technology is the mainstream, Toyota's main hybrid, Nissan pure electric, BYD: pure electric technology, dual-mode technology (plug-in hybrid).
Battery technology: lithium battery technology, fuel cell technology (Hydroyen Feul), metal-air battery technology. The more mature technology is lithium-ion battery technology.
Lithium-ion battery: Lithium-ion battery system is divided into ternary system, lithium iron silicate system, lithium titanate anode system, carbon nanotubes, graphene addition, fast charging system. The process is divided into winding technology, lamination technology; cylindrical battery, square battery; soft bag technology, aluminum shell technology.
Domestic and international power batteries are mainly classified according to their appearance: winding cylindrical batteries, laminated soft pack batteries, and laminated aluminum shell batteries.
Process route: At present, the lithium ion battery process has two types of batteries: cylindrical and square. The cylinder is mainly represented by 18650 and 26650. The square mainly has two kinds of aluminum shell and aluminum plastic film soft pack, which is divided into winding in the manufacturing process. Process and lamination process, the soft package is mainly based on the lamination process, and the aluminum shell is mainly based on the winding process. At present, there are a few enterprises in the domestic power battery that use the soft package winding process. In general, each process has its own advantages and advantages. The disadvantage is that it aims to produce the best battery for electric vehicles.
Comparison of power battery winding and lamination process:
Soft pack laminates and aluminum shell laminates:
Comparison of different monomer group modules: According to the effect of the two PACK processes, the aluminum shell battery can be directly assembled into a power battery pack, and the flexible package battery needs to be reinstalled in a metal shell or a plastic shell with high mechanical strength and good heat dissipation. The PAKC application is carried out again, which adds considerable cost and process complexity.
Main power battery companies and product forms at home and abroad:
Major national new energy vehicle targets for 2020:
According to the calculation of 5 million vehicles, the battery needs 200 million KWH.
Conclusion: Large-capacity square batteries are the development direction of power batteries. In Japan, 18650 cylindrical battery-based, fully automated production equipment, from the mature nickel-hydrogen battery industry; in China, the development of fully automated production equipment for large-capacity batteries, the continuous development and maturity of the process route, guaranteed a large The quality, consistency and safety of the capacity battery also ensure the implementation of the power group technology.