The energy density of lithium iron phosphate batteries is much different than that of ternary lithium batteries.
The energy density of lithium iron phosphate batteries is usually between 90-120Wh/kg, while the energy density of ternary lithium batteries can reach about 200Wh/kg. It can be seen that the energy density advantages of ternary lithium batteries are relatively clear.
The decomposition temperature of the positive electrode material of the ternary lithium battery is about 200 ℃, and the decomposition temperature of the positive electrode material of the lithium iron phosphate battery is about 700 ℃. In the laboratory test environment, short-circuit lithium iron phosphate battery cells basically do not catch fire. This is not the case for ternary lithium batteries. Especially when using ternary lithium batteries, higher requirements for thermal management must be put forward. For vehicle battery packs, safety measures are more complete and scientific, and lithium batteries can be effectively managed through BMS, and the batteries can work in a safe state.
From the three northeastern provinces at the northernmost point to the Hainan Islands at the southernmost point, temperature changes are very abundant. Take Beijing as an example. As the main market for electric vehicles, the highest temperature in Beijing in summer is around 40°C, while in winter it is basically kept at minus 16°C or even lower. Such a temperature range is obviously suitable for ternary lithium batteries with better low-temperature performance. However, the lithium iron phosphate battery, which pays attention to high temperature performance, will appear a bit weak in the winter in Beijing. What's more, the high temperature resistance of ternary lithium batteries is not much different than that of lithium iron phosphate.
Charge and discharge efficiency
Charging is also an important part of the actual use of electric vehicles, and the ternary lithium battery has a great advantage over the lithium iron phosphate battery in terms of charging efficiency.
It can be seen from the table that when the ternary lithium battery and the lithium iron phosphate battery are charged below 10C, there is no significant difference in the constant current ratio. When charging at a rate above 10C, the constant current ratio of the lithium iron phosphate battery decreases rapidly, and the charging efficiency decreases rapidly.