Method for testing sealing property of battery, and method for testing quality of battery

Abstract

The invention provides a method for testing the sealing property of a battery, and a method for testing the quality of the battery. The method for testing the sealing property of the battery comprisesthe following steps: performing a first vacuum treatment on a battery preform to be tested; performing an inflation treatment on the battery preform to be tested subject to the first vacuum treatment, comprising performing a second vacuum treatment on the battery preform to be tested after injecting a gas to be detected into the battery preform to be tested; performing a sealing treatment on thebattery preform to be tested subject to the second vacuum treatment to obtain a battery to be tested; detecting whether the gas to be detected leaks from the battery to be tested to obtain the sealingproperty of the battery to be tested; if no gas to be detected leaks from the battery to be tested, indicating that the sealing property of the battery to be tested is good; and if the gas to be detected leaks from the battery to be tested, indicating that the sealing property of the battery to be tested is not good. The method is simple and convenient to operate and is easy to implement, the battery after the sealing property is tested still has a relatively high vacuum degree, so that the battery is unlikely to generate expansion in a charging and discharging process, and the cycle performance of the battery is not affected.

Description

technical field [0001] The invention relates to the technical field of materials, in particular to a method for testing battery sealing and a method for testing battery quality. Background technique [0002] At present, as people's awareness of environmental protection continues to increase, electric vehicles will gradually replace fuel vehicles, and the main power of electric vehicles comes from batteries, among which lithium-ion batteries are currently one of the most important power sources for electric vehicles. After the lithium-ion battery is produced and before it reaches consumers, a series of performance tests are required to ensure the safety of the battery to the greatest extent and reduce potential safety hazards. Among them, testing the sealing of the battery is a very important item. test. As we all know, when the battery leaks, there will be many problems such as electrolyte volatilization, moisture infiltration, swelling, etc., which will lead to poor batter...

AI Technical Summary

Problems solved by technology

[0006] The inventor conducted in-depth investigations and a large number of experimental verifications on the phenomenon that the cycle performance of batteries that have passed the airtightness test in the related art will become poorer than that of batteries that have not passed the airtightness test. High-energy-density battery negative electrodes (such as silicon-carbon negative electrodes) have certain volume expansion problems during charging and discharging. For example, during the charging and discharging process of silicon-carbon negative electrodes, the volume of silicon will expand by 100% to 300%.

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