A low temperature lithium ion battery

Abstract

The invention relates to a low-temperature lithium-ion battery, comprising a positive pole piece, a negative pole piece, a diaphragm, a low-temperature electrolyte and a shell, and the positive pole piece and the negative pole piece include a positive active material, a negative active material, a binder and Conductive agent. The positive electrode active material is one or more mixtures of lithium cobaltate, lithium manganese oxide, and lithium iron phosphate, and the positive electrode active material accounts for 80%-97% of the total mass of the positive electrode sheet coating, and the compaction of the coating is The density is 3.2-3.5, and the density of one side of the positive pole piece coating is 50-210g / ㎡. The negative electrode active material is artificial graphite, and the negative electrode active material accounts for 85%-95% of the total mass of the negative electrode sheet coating. The compacted density of the coating is 1.2-1.45, and the single surface density of the negative electrode sheet coating is 40-110g / ㎡. The low-temperature electrolyte is composed of the following components by mass percentage: 5-20% lithium hexafluorophosphate, 1-5% lithium tetrafluoroborate, 20-30% ethylene carbonate, 20-30% ethyl methyl carbonate , 20‑40% methyl acetate, 0.5‑2% ethyl sulfite, 0.5‑2% N,N‑dimethyltrifluoroacetamide.

Description

technical field [0001] The invention relates to a low-temperature lithium ion battery. Background technique [0002] At present, lithium-ion batteries are widely used in various fields such as consumer electronics, automobiles, electric vehicles, and energy storage because of their high voltage and high energy density, clean and efficient, and no pollution to the environment. Polymer organic matter is used as a solvent, and each solvent has a certain melting point, boiling point and flash point, and the temperature varies greatly between places on the earth. Therefore, there are still some shortcomings in the use of lithium-ion batteries, and the scope of their use is limited. Especially in low-temperature occasions such as special communications, life in alpine regions, polar scientific research, and aerospace fields, there are high requirements for low-temperature discharge of lithium-ion batteries. However, when the ambient temperature used is too low, the performance of...

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