The aging law of low temperature charging of lithium-ion battery 2019-01-1204
With the rise of new energy vehicles, lithium-ion batteries have been widely used. However, the safety, cruising range and practicality of electric vehicles are still major obstacles to their development. Among them, the low-temperature performance of electric vehicles is receiving more and more attention. Lithium-ion batteries have poor low-temperature performance. At low temperatures, not only the charging efficiency is lowered, but also the energy that can be flushed is reduced, thereby accelerating battery aging. At present, the mechanism and influence factors of battery discharge aging have been studied relatively well, but there are few researches on low temperature charging aging of batteries. In this paper, the effects of temperature, discharge rate and cut-off voltage on the low temperature charge aging rate of the battery were analyzed by low temperature charging experiment, and the relationship between the influence factor and the battery capacity decay rate was quantified. And based on the low temperature aging mechanism, the aging law of lithium ion battery during low temperature charging was analyzed. Studies have shown that at lower temperatures, the lower the temperature, the weaker the diffusion capacity of the battery, and the faster the aging rate due to lithium deposition. The larger the charging current, the more severe the current damage to the battery electrode structure, and the negative electrode electromotive force is significantly reduced, thereby inducing lithium deposition, resulting in a faster aging rate. The higher the charge cut-off voltage, the more severe the damage of the embedded and deposited lithium on the electrode structure, and the faster the aging.