Diagnosis method for short-term exhaustion failure of lithium iron phosphate power battery

Abstract

The invention provides a diagnosis method for a short-term exhaustion failure of a lithium iron phosphate power battery in order to solve the problem that an existing failure diagnosis method for a power lithium battery cannot extract early-stage failure symptoms in the initial stage with small changes of internal resistance and capacity. An impedance and capacity relative change rate and an incremental quantity analysis technology are utilized, an internal resistance change degree of a current battery cell is evaluated, internal causes of the internal resistance change are analyzed, the riskthat the lithium battery has the short-term exhaustion failure is evaluated according to the internal causes of the internal resistance change, and the problem that a current diagnosis method cannot make an early warning for the condition of the sharp deterioration of battery performance is solved. The short-term exhaustion failure diagnosis method can accurately identify the short-term exhaustionfailure of the lithium iron phosphate power battery; and particularly, in the failure initial stage, under the condition that the internal structure of the battery is damaged but the changes of the internal resistance and the capacity are both small, a diagnosis algorithm can differentiate and analyze the internal mechanism of the battery internal resistance change accurately, potential risks arediagnosed, and a failure early warning is carried out.

Description

technical field [0001] The invention relates to the field of fault diagnosis of a power lithium battery, in particular to a diagnosis method for a short-term failure fault of a lithium iron phosphate power battery, which provides an early warning for a sharp change in the performance of the power lithium battery. Background technique [0002] Internal resistance is an important parameter to measure the health status of the power battery. It can not only reflect the information of battery aging to a certain extent, but also is an important factor affecting the internal heat generation of the battery. Therefore, a large number of studies have been carried out in the field on the estimation of the internal resistance of power lithium batteries or the use of internal resistance as the basis for battery aging or fault diagnosis. The performance of the power lithium battery will fail rapidly in a short period of time under certain conditions. The failure phenomena include a sharp ...

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Problems solved by technology

[0005] In order to solve the problem in the existing fault diagnosis technology that the short-term failure diagnosis of the power lithium battery cannot extract the early symptoms of the fault, the present invention provides a diagnostic method for the short-term failure of the lithium iron phosphate power battery

A diagnostic method for short-term failure of lithium iron phosphate power battery according to the present invention uses the relative change rate of impedance capacity and incremental analysis technology to evaluate the degree of change in the internal resistance of the current battery cell, and the risk of short-term failure Make an assessment to compensate for the inability of current diagnostic methods to provide early warning of rapid deterioration of battery performance

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