Method for improving high-temperature storage gas production quantity of flexibly-packaged square lithium ion battery

Abstract

The invention improves a method for improving high-temperature storage gas production quantity of a flexibly-packaged square lithium ion battery. The method is characterized by comprising the following steps of 1) performing electrolyte injection and sealing of the flexibly-packaged square battery, and then performing cold and heat shaping and flat pressing; 2) putting the battery into a drying oven, and standing for 4-24h at a high temperature of 40-100 DEG C; 3) taking the battery out of the drying oven and cooling; 4) putting the battery on a shaping clamping plate; 5) performing formation: performing constant-current charging at 0.01-0.2C until SOC reaches 50-90%; 6) performing aging in an aging room, and standing for 18-48h at a high temperature of 40-45 DEG C; and 7) removing gas and sealing. According to the method, after electrolyte injection and sealing of the flexibly-packaged square battery are performed, the battery is put into the drying oven firstly, and then the battery is aged, so that residual amount of a gas-producing solvent and an additive in the electrolyte can be greatly reduced; reproduction of gas in a post period, when an SEI film is in contact with graphite in conditions that the SEI film suffers from thermal impact and the like and suffers from self decomposition and damage, can be reduced and suppressed to the largest extent; and it is ensured that the gas-producing solvent and additive are fully exhausted through reaction before formation.

Description

technical field [0001] The invention relates to the technology in the field of batteries, in particular to a method for improving the high-temperature storage gas production of soft-packed square lithium-ion batteries. Background technique [0002] At present, the industry uses aluminum-plastic film as the outer casing of the soft-packed lithium battery. Generally, after liquid injection, the process of standing at room temperature and then forming is adopted. This production step, due to the reaction speed of the electrolyte and the graphite at the negative electrode, is due to the battery standing at room temperature. Slow and insufficient, there are more gas-generating solvents and additives in the electrolyte. After forming a film, due to the isolation effect of the SEI protective film, a large amount of gas-generating solvents and additives are separated from the graphite, and the reaction Temporarily stop, if the SEI film of the battery undergoes self-decomposition aft...

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Problems solved by technology

[0002] At present, the industry uses aluminum-plastic film as the outer casing of the soft-packed lithium battery. Generally, after liquid injection, the process of standing at room temperature and then forming is adopted. This production step, due to the battery standing at room temperature, the reaction speed of the electrolyte and the graphite of the negative electrode Slow and insufficient, there are more gas-generating solvents and additives in the electrolyte. After forming a film, due to the isolation effect of the SEI protective film, a large amount of gas-generating solvents and additives are separated from the graphite, and the reaction Temporarily stop, if the SEI film of the battery undergoes self-decomposition after high temperature and other impacts, and the protective isolation effect disappears, the gas-generating solvent and additives will come into contact with graphite again, and side reactions will continue to produce gas, resulting in battery bulging

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