Measuring and calculating method and apparatus of SOH of battery of electric vehicle

Abstract

The invention provides a measuring and calculating method of the SOH of a battery of an electric vehicle. The method includes following steps: S1, measuring a SOH value of the current battery through a battery cyclic coulometric method, wherein SOH1=1-Q / (5Qt), Q is the accumulated discharge quantity of the battery, and Qt is the discharge quantity of the battery in a lifetime period range; S2, measuring the SOH value of the current battery through a volumetric method, wherein SOH2=QN / QC, QN is the maximum capacity of the current battery, and QC is the nominal capacity of the battery; and S3, determining whether SOH1 and SOH2 are the same, wherein the real-time SOH value of the battery is SOH1 if yes, and if not, Qt is corrected, the corrected Qt=Q / (5(1-SOH2)), and SOH1 is calculated according to the corrected Qt. Compared with the prior art, according to the method, high-precision and real-time monitoring of the battery can be realized with the combination of characteristics of the cyclic coulometric method and the volumetric method.

Description

technical field [0001] The invention relates to the field of electric vehicles, in particular to a method and device for measuring and calculating the SOH of an electric vehicle battery. Background technique [0002] A battery pack or battery pack, with continuous charge and discharge cycles, the battery capacity will continue to decrease, and the battery will continue to age. This indicator for judging battery aging is SOH (battery state of health). Monitoring the SOH state of the battery can know the aging state of the battery in time, and perform maintenance and replacement of the battery pack in time. [0003] At present, there are several methods for testing battery SOH: one is to study the relationship between capacity decay and internal resistance increase and SOH from the perspective of battery aging mechanism; the other is to measure battery SOH off-line through standard test experiments from an experimental point of view; One is to establish a battery model, and u...

AI Technical Summary

Problems solved by technology

[0005] 1. Due to the scattered distribution of battery internal resistance, the internal resistance difference between different batteries is relatively large, and the relationship between internal resistance and SOH is not universal

[0006] 2. The standard experimental test of SOH requires offline testing, which is time-consuming and labor-intensive. It requires special testing equipment, which is expensive, and the cost of battery pack testing is even greater.

[0007] 3. The algorithm of the battery model method is complicated, and it is difficult to establish a battery model, so it is difficult to get a good application in practice

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