Method for quantitatively detecting micro short-circuit fault of series lithium ion battery pack

Abstract

The invention provides a method for quantitatively detecting a micro short-circuit fault of a series lithium ion battery pack. The method comprises steps of establishing a relation curve of an open-circuit voltage (OCV) and a state of charge (SOC) of a battery system through a hybrid pulse power performance test (HPPC) in advance, forming a battery pack by connecting n single batteries in series,and recording a total current, a total voltage, a single battery voltage and a single battery surface temperature of the battery pack in real time by a battery management system; estimating an OCV ofthe battery based on an improved double Kalman filter (DEKF); calculating to obtain the SOC of the battery through an interpolation method, so calculating to obtain SOC difference between the batteries. A linear fitting method is further adopted to estimate short-circuit current and short-circuit resistance, if the current is about zero, external short-circuit resistance is infinite, and no short-circuit fault occurs; if the current is not zero, external short-circuit resistance of the battery can be calculated according to the ohm law. The method is advantaged in that quantitative detection of the micro short-circuit fault of the series lithium ion battery pack can be realized, and the magnitude of the external short-circuit resistance is outputted to evaluate severity of the fault.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery packs, in particular to a quantitative detection method for micro-short-circuit faults of series-connected lithium-ion battery packs. Background technique [0002] Under the dual pressure of energy crisis and environmental pollution, lithium-ion batteries have gradually become one of the main choices of power sources for electric vehicles due to their high energy density, long cycle life, low pollution, low self-discharge and no memory effect. At the same time, safety issues have become increasingly prominent, which has attracted great attention from the industry. Lithium-ion batteries are prone to thermal runaway under abuse conditions, including thermal abuse, mechanical abuse, and electrical abuse, among which external short circuit of the battery is one of the most common forms of electrical abuse. When the positive and negative electrodes of the battery are directly short-circuit...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that it is difficult to identify micro-short-circuit faults in series lithium-ion battery packs, and proposes a method for on-line quantitative detection of micro-short-circuit faults in series-connected battery packs based on an improved double Kalman filter (DEKF)

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