Electric vehicle soh correction method and device

Abstract

The invention discloses an SOH correction method and device for an electric automobile. The correction method comprises the following steps: confirming that a battery pack enters a charging mode; detecting an SOC calculated value in real time; judging whether the battery pack is in a slow charging state; correcting the SOC calculated value; judging whether to exit the charging mode; judging whether the battery pack reaches a full charging state; searching the charging record; judging whether the SOC calculated value jumps to 100% or not in the charging process according to the charging record;recording the SOC calculated value during jumping to be an SOC jump value; acquiring an SOH assessed value; calculating an SOH corrected value by dichotomization; updating the current SOH value according to the SOH corrected value, and finally exiting correction. According to the correction method disclosed by the invention, the SOH level is automatically corrected in a daily charging process, sothat the method is flexible in operation and high in practicality, and a driver can accurately master the health state of the battery pack.

Description

technical field [0001] The invention relates to the field of electric vehicles, in particular to an electric vehicle SOH correction method and device. Background technique [0002] As the capacity of the power battery pack of electric vehicles continues to decline, the state of health of the battery pack (reflected by the SOH value) is also constantly declining. Therefore, it is necessary to estimate the SOH value to evaluate the relationship between the remaining capacity of the battery pack and the effective utilization rate. [0003] Usually, the battery management system evaluates the SOH based on reference values ​​such as battery cell status such as cell voltage and cell internal resistance. However, due to the poor consistency of the battery pack, the reference values ​​used in the evaluation have large limitations and errors. , which in turn will lead to a deviation in the accuracy of the obtained SOH evaluation value; and the current mainstream algorithm for the st...

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Problems solved by technology

[0003] Usually, the battery management system evaluates the SOH based on reference values ​​such as battery cell status such as cell voltage and cell internal resistance. However, due to the poor consistency of the battery pack, the reference values ​​used in the evaluation have large limitations and errors. , which in turn will lead to a deviation in the accuracy of the obtained SOH evaluation value; and the current mainstream algorithm for the state of charge (SOC) of the battery pack is to use the ampere-hour integration: SOC calculation value = SOC 起始 -(∫A.h / (C 出厂满电容量 ×SOH current value)), where the current SOH value refers to the current SOH value, that is, the SOH evaluation value obtained through the aforementioned evaluation method, so inaccurate SOH evaluation value will also cause SOC errors, for example, the SOH evaluation value is higher than If the actual SOH value is too large, the actual SOC value of the battery pack will be smaller than the SOC display value seen by the driver (SOC display value is the SOC calculation value), which will cause misleading to the driver, and may even cause the electric vehicle to run Forced to stop halfway due to insufficient power

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