How to judge whether the lithium iron phosphate battery is safe?
New energy vehicle consumers who attach importance to battery life and lighter vehicles should use ternary batteries, while consumers who attach importance to safety should use lithium iron phosphate batteries. So how should we judge whether the lithium iron phosphate battery is safe? This question is mainly answered from three aspects: material/structural stability, production process, and charge-discharge characteristics.
Material
Lithium iron phosphate is the safest cathode material for lithium-ion batteries at present. It does not contain any heavy metal elements that are harmful to the human body. It is difficult to precipitate oxygen in its olivine structure, which improves the stability of the material.
Production process
The core processes of lithium iron phosphate batteries are: batching, coating, rolling, filming, and winding. In the batching process, the lithium iron phosphate material has relatively poor electrical conductivity, so the particles are generally made smaller, which can make the internal arrangement more uniform, thereby promoting the battery to form a balanced voltage platform and more stable during operation.
In terms of charge and discharge characteristics
Charging and discharging are two basic working states of lithium batteries. When the lithium iron phosphate battery is charged and discharged, due to the weak oxidation ability of iron ions, it will not release oxygen, so it is naturally difficult to have a redox reaction with the electrolyte, which makes the charging and discharging process of the lithium iron phosphate battery in a safe environment. Not only that, it is difficult for lithium iron phosphate batteries to undergo severe redox reactions during high-rate discharge or even overcharge and discharge. At the same time, after the lithium is deintercalated, the lattice change will reduce the final volume of the unit cell (the smallest constituent unit of the crystal), which just offsets the increased volume of the carbon negative electrode during the reaction. Therefore, during charging and discharging, lithium iron phosphate batteries The stability of the physical structure can be maintained, and the hidden danger of the battery bursting phenomenon caused by the increase in volume is eliminated.
