Differences between lithium iron phosphate batteries and ternary lithium batteries

Lithium iron phosphate battery is a lithium-ion battery that uses lithium iron phosphate as the positive electrode material and carbon as the negative electrode material. During the charging process, some lithium ions in lithium iron phosphate are removed and transferred to the negative electrode through the electrolyte, which is embedded in the negative electrode carbon material; At the same time, electrons are released from the positive electrode and reach the negative electrode from the external circuit, maintaining the balance of chemical reactions. During the discharge process, lithium ions detach from the negative electrode and reach the positive electrode through the electrolyte. At the same time, the negative electrode releases electrons, and when they reach the positive electrode from the external circuit, a current is generated to provide energy to the outside world.

The electrochemical performance of the positive electrode material for lithium iron phosphate batteries is relatively stable, so the structure of the battery will not change during the charging and discharging process, and it will not burn or explode. Even under special conditions such as short circuit, overcharging, squeezing, and puncture, it is still very safe. Lithium iron phosphate batteries have the advantages of high working voltage, long cycle life, good safety performance, low self discharge rate, no memory effect, and low production cost. The disadvantages are low energy density, poor low-temperature resistance, and significant differences in high and low temperature charging and discharging rates.

Ternary lithium batteries have nickel cobalt lithium manganese oxide or nickel cobalt lithium aluminate as the positive electrode material, and commonly used are ternary composite materials made of nickel salt, cobalt salt, and manganese salt as the positive electrode material. During the charging process, some lithium ions in the ternary composite material are removed and transferred to the negative electrode through the electrolyte, which is embedded in the negative carbon material; At the same time, electrons are released from the positive electrode and reach the negative electrode from the external circuit, maintaining the balance of chemical reactions. During the discharge process, lithium ions detach from the negative electrode and reach the positive electrode through the electrolyte. At the same time, the negative electrode releases electrons, and when they reach the positive electrode from the external circuit, a current is generated to provide energy to the outside world.

Ternary lithium batteries have smaller volume, higher capacity density, low temperature resistance, and better cycling performance. However, its high temperature resistance is poor, and it decomposes at 250-300 ℃, resulting in particularly strong chemical reactions in ternary lithium materials. Once oxygen molecules are released, the electrolyte will rapidly burn under high temperature, leading to detonation; The cycle life is short, with a general number of cycles of 1200, which can basically meet the current warranty period of about 8 years for new energy vehicles, and the cost is relatively high compared to lithium iron phosphate.