Lithium ion battery self-discharge screening and matching method

Abstract

The invention provides a lithium ion battery self-discharge screening and matching method. The method comprises the steps of charging a capacity-graded battery to a preset state of charge, and selecting alternative batteries of which the battery voltage is within a set range; According to the method, the battery is capacity-graded; the battery with the first-grade capacity is tested, meanwhile, the subsequent voltage difference and the numerical value of the DC internal resistance DCIR are analyzed, so as to guarantee that the difference among the capacity, the self-discharge voltage and the internal resistance of the assembled battery is small; the problems of large voltage difference, rapid capacity attenuation and the like in the using process of the lithium ion battery due to mismatching of the assembled battery are solved; high-temperature shelving of the battery is beneficial to infiltration of the electrolyte of the lithium ion battery, and micro short-circuit points in the battery can be aggravated due to the high-temperature expansion effect, so that later-period self-discharge screening is facilitated; the method is convenient to operate; the cycle performance and safetyperformance of the battery pack are improved; the method is suitable for batch production; the product quality requirement is met; and a basis is provided for single battery process inspection.

Description

technical field [0001] The invention relates to the field of lithium ion technology, in particular to a method for self-discharge screening and grouping of lithium ion batteries. Background technique [0002] As the heart of new energy electric vehicles, ships, industrial vehicles, and base station energy storage, lithium-ion batteries have the advantages of long cycle life, high specific energy, fast charge and discharge, wide operating temperature range, strong adaptability, and environmental protection. It is highly valued by the country and various industries, and is a strategic direction firmly supported by the country; lithium-ion batteries are composed of battery modules and battery systems in series and parallel. In order to ensure the stable operation of the lithium-ion battery system, it is particularly important for the screening and matching of lithium-ion batteries to be consistent. [0003] Lithium-ion battery self-discharge refers to the capacity loss caused ...

AI Technical Summary

Problems solved by technology

Because the lithium-ion battery is left in the state of constant current and constant voltage full charge, the voltage difference fluctuates greatly, and the charging method of the lithium-ion battery system cannot perfectly realize the constant current and constant voltage mode, resulting in the large dynamic pressure difference of the battery screened by this method , the difference of the battery system is constantly enlarged and bad during the use process, which cannot meet the needs of users

Moreover, the fully charged lithium-ion battery has a large self-discharge during storage, and the battery capacity decays quickly and cannot be recovered; the fully charged lithium-ion battery has a slight short circuit or a complete short circuit safety accident caused by misoperation during the assembly process.

[0004] Aiming at the deficiencies of the existing technology, we propose a method of lithium-ion self-discharge screening and grouping to solve the problem of rapid capacity decay and time-consuming problems of lithium-ion batteries in stock due to the large pressure difference during the use of lithium-ion batteries and the lack of grouping for the time being. security incidents etc.

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