Lithium-ion battery screening method

Abstract

The invention relates to a lithium ion battery screening method, comprising: discharging the lithium ion battery with a constant current I1 to the inflection point voltage of the lithium ion battery discharge curve; shelving for a certain time T1, and the open circuit voltage of the lithium ion battery rises to U1 , where U1 is greater than the inflection point voltage of the lithium-ion battery discharge curve; discharge the lithium-ion battery with a constant current I2 to the inflection point voltage of the lithium-ion battery discharge curve, where I2<

Description

technical field [0001] The invention relates to lithium ion batteries, in particular to a method for screening lithium ion batteries for eliminating batteries with large self-discharge. Background technique [0002] Lithium-ion batteries are energy-saving products with high specific energy, high cycle performance, and no memory benefit. It has been widely used in photovoltaic energy storage, power vehicles, electric tools and digital products and other industries, and its pollution-free performance has gradually replaced lead-acid batteries. Although the manufacturing performance of single cells is generally improved, lithium-ion battery modules still have uneven self-discharge, and even the single cycle can exceed 2000-3000 times, but the general performance of the group has dropped by 15%. The main reason is that It is because self-discharge and sorting technology is not enough. [0003] At present, the general PACK sorting usually only selects batteries with a small gap...

AI Technical Summary

Problems solved by technology

Although the manufacturing performance of single cells is generally improved, lithium-ion battery modules still have uneven self-discharge, and even the single cycle can exceed 2000-3000 times, but the general performance of the group has dropped by 15%. The main reason is that Self-discharge and sorting technology is not enough

[0003] At present, the general PACK sorting usually only selects batteries with a small gap in capacity and internal resistance, and assembles them into modules, but often ignores the aspect of self-discharge, which results in poor performance of group cycles

In addition, the existing technology generally controls the cut-off voltage of charge and discharge, but due to the inconsistent self-discharge voltage of lithium-ion batteries, as the discharge time prolongs, the voltage drop is inconsistent, thereby shortening the cycle performance of lithium-ion battery modules

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