Method for evaluating excess coefficient of lithium ion battery negative electrode

Abstract

The present application relates to a kind of lithium ion battery negative electrode excess coefficient evaluation method, comprising the following steps: S1: according to different negative electrode excess coefficient preparation several lithium iron phosphate batteries;S2: the lithium battery is respectively divided into capacity processing, carries out charge-discharge charge-discharge charge process, collects the second charge capacity Q and voltage V data, draws dQ / dV-V curve, dQ / dV-V curve includes three peaks from left to right, peak one, peak two, peak three;S3: the two peak values of peak two and peak three in each dQ / dV-V curve are compared respectively;S4: the negative electrode excess coefficient of peak three peak value equal to peak two peak value is used as optimal negative electrode excess coefficient.The evaluation method of the present application is in the conventional negative electrode excess coefficient range of lithium ion battery of lithium iron phosphate, further selects more excellent negative electrode excess coefficient, so that lithium iron phosphate battery has capacity and safety problem.

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