Method for effectively screening self-discharging batteries

Abstract

The invention relates to a method for effectively screening self-discharging batteries. The method comprises the following steps: (1) determining low-voltage-state voltage knee points of batteries by using a trickle charge method; (2) carrying out charging and discharging on the batteries, allowing the voltage of the batteries to be finally located at the low-voltage-state voltage knee points, and after the voltage of the batteries tends to be stable, measuring and recording the voltage OCV1 of each battery; (3) storing the batteries at a set temperature for a period of time and measuring and recording the voltage OCV2 of each battery; and (4) calculating the voltage drop value delta V of each battery, wherein delta V satisfies the equation that delta V = OCV1 - OCV2, and if the voltage drop value delta V of a battery exceeds a set value, the battery is a self-discharging battery need to be screened out. The method provided by the invention is more scientific, accords with principles, can more accurately screen out self-discharging lithium ion batteries and reduces irreversible capacity loss of batteries in the phase of screening of self-discharge; thus, excellent electrochemical performance and safety performance of batteries in subsequent usage are guaranteed.

Description

technical field [0001] The invention relates to the field of battery manufacturing, in particular to a method for effectively screening self-discharging batteries. Background technique [0002] Lithium-ion battery self-discharge refers to the phenomenon that the voltage of the battery automatically drops during the open-circuit static process. Among the electrodes of various systems, the self-discharge phenomenon of lithium-ion batteries is inevitable. Lithium-ion battery self-discharge can be divided into two types according to whether it can recover after capacity loss: reversible capacity loss, which means that the capacity can be recovered after recharging; irreversible capacity loss, which means that the capacity cannot be recovered. [0003] There are many factors that affect the degree of self-discharge, which can be roughly divided into: the preparation process of the pole piece and the battery, the nature and concentration of the electrolyte, the storage temperature...

AI Technical Summary

Problems solved by technology

[0004] The present invention mainly solves the technical problem that the original lithium-ion battery self-discharge screening method is unscientific, and there are serious deficiencies in principle and technology, which lead to easy misjudgment of non-self-discharge batteries, but difficult detection of real self-discharge batteries; provides a A method for effectively screening self-discharging batteries, which is more scientific and can more accurately screen out self-discharging lithium-ion batteries, thereby ensuring excellent electrochemical performance and safety performance in the subsequent use of batteries

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