Low-temperature lithium-ion battery

Abstract

The invention relates to a low-temperature lithium-ion battery, which comprises a positive pole piece, a negative pole piece, a membrane, a low-temperature electrolyte and a housing, wherein each of the positive pole piece and the negative pole piece comprises a positive active material, a negative active material, a binder and a conductive agent; the positive active material is one or a mixture of more of a lithium cobalt oxide, lithium manganate and lithium iron phosphate and accounts for 80%-97% of total mass of a coating of the positive pole piece, the compaction density of the coating is 3.2-3.5 and the single-sided surface density of the coating of the positive pole piece is 50-210g / m<2>; the negative active material is synthetic graphite and accounts for 85%-95% of total mass of the coating of the negative pole piece, the compaction density of the coating is 1.2-1.45, the single-sided surface density of the coating of the negative pole piece is 40-110g / m<2>; and the low-temperature electrolyte is prepared from the following components in percentage by mass: 5%-20% of lithium hexafluorophosphate, 1%-5% of lithium tetrafluoroborate, 20%-30% of ethylene carbonate, 20%-30% of methyl ethyl carbonate, 20%-40% of methyl acetate, 0.5%-2% of glycol sulfite and 0.5%-2% of N,N-dimethyl trifluoroacetamide.

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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Problems solved by technology

The above factors seriously restrict its use under low temperature conditions.

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