Lithium battery is currently one of the most commonly used battery types in electric vehicles. Although it has not been a long time since its birth in 1970, it quickly occupied the largest market of electric vehicle batteries due to its high energy density and long cycle life. Part of the country. Nowadays, the lithium batteries equipped with electric vehicles on sale mainly include lithium iron phosphate batteries and ternary lithium batteries, and these two batteries have significant differences in their own characteristics, so it is necessary for us to explain and explain them in detail. Compared.

　　Why is lithium iron phosphate battery safe?

　　Most people may have little knowledge about batteries used in electric vehicles, so we might as well give an example to help everyone understand. Recently, the new electric vehicle brand Denza, jointly funded by BYD and Daimler, is about to go on sale, and it is equipped with lithium iron phosphate batteries. Compared with the earlier lithium manganese oxide batteries, the energy density of lithium iron phosphate batteries is not much different, about 100-110Wh/kg, but its thermal stability is the best among current automotive lithium batteries. When the battery temperature is at a high temperature of 500-600℃, its internal chemical composition begins to decompose, and the lithium cobalt oxide battery, which is also a lithium battery, is already in an unstable state at 180-250℃. In other words, the safety of lithium iron phosphate batteries is second to none in lithium batteries, and because of this, it has become one of the main categories of current electric vehicle batteries.

　　Why did Tesla choose a ternary lithium battery?

　　Compared with the lithium iron phosphate battery, the ternary lithium battery used in Tesla MODEL S is much higher in weight energy density, about 200Wh/kg, which means that the ternary lithium battery of the same weight is higher than that of iron phosphate. Lithium batteries have a longer cruising range. However, its shortcomings are also obvious. When its own temperature is 250-350℃, the internal chemical components begin to decompose. Therefore, extremely high requirements are placed on the battery management system. It is necessary to install a safety device for each battery. Because of the small size of the cells, the number of battery cells required for a bicycle is very large. Taking MODEL S as an example, more than 7000 18650 ternary lithium batteries can meet the assembly consumption of a car. This is undoubtedly a further step for the battery management system. Increased the difficulty of control. Therefore, among the current models on the market, only Tesla uses a ternary lithium battery.