Lithium precipitation detection method for lithium iron phosphate power battery

Abstract

The invention discloses a lithium precipitation detection method for a lithium iron phosphate power battery, and relates to the technical field of lithium ion power battery detection. The method comprises the steps of employing different multiplying power currents to perform low-temperature floating charge-discharge cycle on a battery, determining the charge constant-current charge ratio and the discharge average voltage data of each cycle, and drawing a curve graph; standing the battery at a low temperature; increasing the floating charge voltage, performing low-temperature floating charge-discharge cycle on the battery after standing at the low temperature, measuring the charge constant-current charge ratio and the discharge average voltage data of each cycle, and drawing a curve graph,wherein the low-temperature floating charge-discharge cycle adopts a three-section charge-discharge mode including stepped charge, floating charge and constant-current discharge; and comparing the constant-current charge ratio curve graph and the discharge average voltage curve graph before and after low-temperature standing, and judging whether the battery is subjected to lithium precipitation ornot according to the curve fluctuation range. The method is simple to operate, whether the lithium ion battery is subjected to lithium precipitation or not can be accurately judged without disassembling the battery, and a battery lithium precipitation window can be quickly established.

Description

technical field [0001] The invention relates to the technical field of lithium ion power battery detection, in particular to a lithium iron phosphate power battery detection method for lithium analysis. Background technique [0002] Lithium-ion batteries have become the main energy source of current electric vehicles due to their advantages of high energy density, long life and low self-discharge rate. When the lithium-ion battery is used at low temperature, the lithium ions in the graphite negative electrode may be reduced to metal lithium, and lithium precipitation occurs. Lithium precipitation occurs in the battery, which will cause a rapid decline in capacity; on the other hand, the precipitated metal lithium forms lithium dendrites that may pierce the diaphragm, induce internal short circuit, and cause serious safety accidents. Therefore, it is necessary to judge in advance whether the lithium ion battery is lithium-ion. . At present, the commonly used method is to di...

AI Technical Summary

Problems solved by technology

The above two judgment methods only consider a single factor to judge whether to analyze lithium, which is not necessarily accurate

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