Detailed analysis of power battery development technology

　　With the increasing development of new energy technologies and the country's gradual attention to the environment, industries such as electric vehicles, robots, and hybrid vehicles are increasingly demanding power batteries.

　　With the increasing development of new energy technology and the country's gradual attention to the environment, the demand for power batteries in electric vehicles, robots, hybrid vehicles and other industries is increasing. Battery technology is also one of the key technologies that need to be developed. This article introduces how power batteries work, how to work efficiently, future development directions and application areas, and focuses on mainstream lithium batteries.

　　The power battery is the power source that provides the power source for the tool. Generally, we call the battery the power battery. The storage battery is a reversible low-voltage DC power source that realizes the conversion between chemical energy and electrical energy. It was invented by French scientist Gaston Plant in 1859. (As shown in Figure 1).

　　Table 2 shows the performance comparison of lithium cobalt oxide batteries and ternary lithium batteries (ternary nickel-cobalt-manganese).

　　Table 2 Main power lithium batteries and their performance

　　Lithium iron phosphate batteries are mainly used in passenger cars, and ternary batteries have a high penetration rate in passenger cars and special vehicles (see Figure 7). At present, lithium iron phosphate batteries and ternary batteries are the main power batteries (see Table 3). Because lithium iron phosphate as a part of the battery has high stability, that is, the internal crystal structure does not change; the whole production and use process is environmentally friendly and non-toxic and harmless; it uses phosphoric acid source, lithium source and iron source as raw materials, and the price is cheap; high temperature and high pressure resistance , Good stability, high safety factor and other advantages, more and more battery suppliers use lithium iron phosphate as the positive electrode material in power batteries. Many car manufacturers also choose this material when choosing battery parameters based on price and safety considerations (see Figures 8 and 9).

　　Figure 7 2015 power battery output distribution by material system

　　Table 3 2015 China's car companies and battery companies supporting situation

　　Figure 8 Market share of battery manufacturers in 2015

　　Figure 9 Market share of battery manufacturers in the first half of 2016

　　Lithium iron phosphate has many advantages, but it has not been put into large-scale use immediately. The reason is that during the production process, it is necessary to control the ratio of lithium iron phosphate particles in conductive carbon materials and metal particles to achieve good electrical conductivity. The difficulty is that the ratio constantly changes over time, capacity, etc., making large-scale production problems. The second problem is that the tap density can only reach 1.3 ~ 1.5V, making the product difficult to miniaturize. The third problem is that the operating voltage is low, generally 3.2V.

　　Five, ternary lithium battery development prospects

　　The ternary battery has high energy density and good overall performance, and its penetration rate in passenger cars and special vehicles is close to 50%.

　　The ternary battery has a lot of room for performance improvement, and it is expected to become the mainstream in the future. The improvement of the existing ternary lithium battery system can reach the 2020 target of 300Wh/kg power battery module energy density. As passenger cars become the main growth driver for new energy vehicles in the future, ternary batteries are expected to gradually replace lithium iron phosphate batteries and become the mainstream in the future.

　　VI. Conclusion

　　At present, the development of power battery technology has made a lot of progress. Today, with increasing environmental pollution, it is necessary to develop "green" batteries, which are not only good for the living environment of the general public, but also can drive the development of the entire battery industry. At present, the development of new "green" batteries has made great progress. For example, the development of power vehicles, that is, new energy vehicles, and new power batteries as its key components not only drive the development of new energy vehicles, but also will definitely affect the development of batteries. The development of the industry brings spring.