Lithium battery applicable to low-temperature environment

Abstract

The invention discloses a lithium battery applicable to a low-temperature environment. An electrolyte solution thereof consists of the following raw materials in percentages by weight: 0.165-0.2% of ethylene carbonate, 0.27-0.3% of dimethyl carbonate, 0.2-0.25% of ethyl methyl carbonate, 0.9-1.0% of ethyl acrylate, 0.045-0.05% of propylene carbonate, 0.015-0.02% of vinylene carbonate, 0.03-0.04% of lithium tetrafluoroborate, 0.13-0.15% of lithium hexafluorophosphate and 0.02-0.03% of fluoroethylene carbonate. A preparation method of the lithium battery applicable to the low-temperature environment comprises the following steps: preparation of the electrolyte solution, coating, rolling, die cutting, stacking, welding, shelling-in, laser welding, liquid injection, formation, volume grading, normal-temperature testing and low-temperature testing. According to the lithium battery disclosed by the invention, the first discharge capacity under a normal temperature is 60.657 Ah, the first discharge capacity at minus 32+ / -5 DEG C is 54.548 Ah, and the charging and discharging efficiency is about 90%. According to the lithium battery, through the improvement for components and matching of the electrolyte solution, the low-temperature resistance to the battery is obviously improved, the safety performance of the lithium battery is greatly improved, and the lithium battery can be widely applicable to the field of pure electric vehicles.

Description

technical field [0001] The invention relates to the field of pure electric vehicles, in particular to a lithium battery applicable to pure electric vehicles and capable of adapting to low-temperature environments. Background technique [0002] Electric vehicles have the characteristics of low carbon and environmental protection, and are the future development direction of automobiles. With the development of electric vehicle technology, automobile manufacturers have increasingly higher performance requirements for lithium-ion power batteries for electric vehicles. At present, the known lithium-ion batteries for electric vehicles , can only be used at room temperature. When the outside temperature is too low, the electrolyte inside the lithium battery is easy to freeze, causing the lithium battery to be unable to charge and discharge normally at minus 10-20°C. The charging and discharging can only reach 60%, which will cause the battery to decay faster, and chemical crystals ...

AI Technical Summary

Problems solved by technology

[0002] Electric vehicles have the characteristics of low carbon and environmental protection, and are the future development direction of automobiles. With the development of electric vehicle technology, automobile manufacturers have increasingly higher performance requirements for lithium-ion power batteries for electric vehicles. At present, the known lithium-ion batteries for electric vehicles , can only be used at room temperature. When the outside temperature is too low, the electrolyte inside the lithium battery is easy to freeze, causing the lithium battery to be unable to charge and discharge normally at minus 10-20°C. The charging and discharging can only reach 60%, which will cause the battery to decay faster, and chemical crystals will be produced inside the battery. During the charging and discharging process of the battery, it is easy to cause the battery to short-circuit instantly and cause fire, which not only cannot guarantee the normal driving mileage of the electric vehicle , and are prone to safety accidents; based on the above reasons, it is necessary to improve the existing lithium battery electrolyte so that it can still maintain high performance in a low temperature environment and eliminate potential safety hazards

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