Which is better, ternary lithium battery or lithium iron phosphate battery?

Ternary lithium battery and lithium iron phosphate battery have their own advantages and can be selected as needed.

1, ternary lithium battery

High energy density, good cycle performance, more suitable for the future development trend of new energy vehicle batteries, suitable for northern weather, more stable at low temperature; Disadvantages: the high-temperature structure of Ni-Co-Al is unstable, which leads to poor high-temperature safety and danger. But this problem can be improved through various systems, and the current cost is relatively high.

2. Lithium iron phosphate battery

Higher safety, longer service life, low cost of raw materials, support for fast charging, wide working temperature range, and the stability is the best among the lithium batteries for vehicles at present; Disadvantages: There is still a big gap between energy density and ternary lithium battery. When the temperature is lower than a certain level, the charging efficiency will decrease and the battery capacity will be affected. The model of lithium iron phosphate battery is not suitable for driving in the north.

Why does low temperature affect lithium iron phosphate batteries?

The cathode of lithium iron phosphate battery has poor electronic conductivity and is prone to polarization at low temperature, thus reducing the battery capacity. Due to the influence of low temperature, the lithium intercalation rate of graphite decreases, and metallic lithium is easy to precipitate on the surface of the negative electrode. Part of lithium metal continues to exist on the surface of the negative electrode, which is likely to form lithium dendrites and affect the safety of the battery.

At low temperature, the viscosity of electrolyte will increase, and the migration impedance of lithium ion will also increase. In addition, the adhesive is also a key factor in the production of lithium iron phosphate battery, and low temperature will also have a great impact on the performance of the adhesive.

Moreover, low temperature leads to the precipitation of lithium dendrites on the surface of the negative electrode, which will consume lithium ions that can be repeatedly charged and discharged in the battery, greatly reducing the battery capacity. The precipitated lithium dendrites may also pierce the separator, thus affecting the safety performance.