A screening method for lithium-ion battery self-discharge

Abstract

The invention relates to a lithium ion battery self-discharging screening method. The lithium ion battery self-discharging screening method comprises the following steps: S1, performing first-time voltage test on to-be-tested batteries according to a first test standard and screening out the to-be-tested batteries meeting the first test standard; S2, ageing the to-be-tested batteries meeting the first test standard by a preset ageing process; S3, performing second-time voltage test on the to-be-tested batteries aged by the preset ageing process according to a second test standard and screeningout the to-be-tested batteries meeting the second test standard; S4, screening the to-be-tested batteries meeting the second test standard and screening out the to-be-tested batteries with self-discharging SOC being 5 to 15 percent; and S5, screening the to-be-tested batteries with the self-discharging SOC being 5 to 15 percent by a K value method and screening out the to-be-tested batteries meeting the K value. By the method, the self-discharging screening cycle can be effectively shortened, the productivity is improved, the cost is further reduced, the efficiency is high and the accuracy degree is high; furthermore, the quality of products can be improved and the customer complaint risk can be reduced; meanwhile, the delivery cycle of the products can be shortened.

Description

technical field [0001] The invention relates to the field of batteries, more specifically, to a screening method for self-discharge of lithium-ion batteries. Background technique [0002] Self-discharge, also known as charge retention capacity, refers to the ability to maintain the stored power of a battery under certain environmental conditions in an open circuit state. Generally speaking, self-discharge is mainly affected by manufacturing process, materials, and storage conditions. Self-discharge is one of the main parameters to measure battery performance. After strict control of the manufacturing process, it is found that the current conventional self-discharge selection method is to use SOC (Sate of Charge, remaining power) as the selection standard of 50%. Selection method In the actual production line selection process, the qualified rate of self-discharge selection is almost 100%, and the bad self-discharge cells cannot be selected. [0003] Or select with the stan...

AI Technical Summary

Problems solved by technology

Self-discharge is one of the main parameters to measure battery performance. After strict control of the manufacturing process, it is found that the current conventional self-discharge selection method is to use SOC (Sate of Charge, remaining power) as the selection standard of 50%, and the use of this Selection method In the actual production line selection process, the qualified rate of self-discharge selection is almost 100%, and the bad self-discharge cells cannot be selected.

[0003] Or select with the standard △V, and select with the standard △V, the selection accuracy of the bad cells in mass production is less

[0004] In addition, the existing self-discharge selection cycle is too long, resulting in low production capacity, low efficiency, high cost, and also affects the product delivery cycle

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