A method of correcting SOC based on charging curves at different temperatures and rates

Abstract

The invention relates to a method for correcting an SOC based on different temperature and rate charging curves. A battery management system detects and judges whether a battery is charged and a charging current is stable or not; a charging rate is calculated according to the charging current and rated capacity of the battery; the current temperature T of the battery is detected, and the single voltage value Volt_pre and SOC_pre of charging pre-corrected points are obtained by looking up a table according to the T and the charging rate; the current single voltage Volt of a battery pack and the single voltage obtained by looking up the table are compared, and when Volt is greater than Volt_pre, the SOC is corrected to be SOC_pre, or, the SOC does not change. Compared with the prior art, the method has the advantages of improving the accuracy of SOC estimation in the charging process and effectively preventing the battery from large SOC errors under the charging interrupt condition and preventing anchorage when a user drives a car, the number of corrected data of the charging curves needing to be stored is small, operation is easy and fast, and reduction of the cost of the battery management system and application and popularization are facilitated.

Description

technical field [0001] The invention relates to a method for correcting SOC, in particular to a method for correcting SOC based on charging curves of different temperatures and rates. Background technique [0002] SOC (state of charge, which refers to the ratio of the remaining capacity of the battery to its fully charged capacity) as an indicator to measure the remaining capacity of the battery pack plays a very important role for users. Failure to grasp the remaining capacity of the battery may cause electric vehicles to fail The risk of breaking down due to power failure. In order to accurately estimate the SOC of the battery pack, the battery management system (hereinafter referred to as BMS) adopts a variety of different methods to achieve the purpose of accurately estimating the SOC. During the charging process, the BMS will correct the SOC to 100% at the end of charging, that is, when the battery is fully charged. However, due to the different usage habits of users ...

AI Technical Summary

Problems solved by technology

If such a situation occurs several times in a row, there will be a large error in the SOC due to the lack of full correction, which may cause the unfavorable situation of breaking down during operation

[0003] At present, in the field of battery management systems, most companies only use the open circuit voltage method and the ampere-hour integral method to estimate SOC, but these two methods have certain limitations for lithium iron phosphate batteries

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