Lithium ion battery capable of low-temperature working

Abstract

The invention relates to a lithium ion cell fit to low temperature, which comprises: a positive electrode with active material as Li-containing transition metal oxide with D50 size less than 5ª–m, a negative electrode, a non-aqueous electrolyte contained straight-chain ester organic solvent with carbon atom number less than 5. This invention reduces solid-phase ion diffusion distance, enlarges reaction area to decrease reaction and solid-phase diffusion impedances, realizes discharge capacity at -20Deg even -50Deg, and avoids the salt separation and electrolyte solidification.

Description

technical field

[0001] The invention belongs to the technical field of lithium ion batteries, in particular to a lithium ion battery capable of working at low temperature. Background technique

[0002] At present, when the traditional lithium-ion battery is around -20°C, the impedance of the battery is many times higher than that at normal temperature. Moreover, the impedance of its electrolyte increases with the decrease of temperature, and the impedance of charge movement, especially the semicircle impedance on the low-frequency side of the positive electrode becomes very large at low temperature, so that the voltage and discharge capacity have become very low, and when the temperature drops to - At 40°C, EC and LiPF6 have already precipitated, and the electrolyte solidifies so that the battery cannot be used at all. It cannot meet the power requirements of electrical appliances working in cold environments, electric transport carriers, electric tools, etc.

[0003] In o...