Method of correcting state of charge (SOC) based on battery discharge characteristic curves and ampere-hour integral method

Abstract

The present invention discloses a method of correcting SOC based on battery discharge characteristic curves and an ampere-hour integral method. The method comprises the steps of prestoring the discharge characteristic curves of a battery on different temperature conditions, and presetting a plurality of correction points in the discharge characteristic curves, wherein the correction points embody the corresponding discharge voltage Vn and the battery capacity SOCn; detecting the current environment temperature T, and selecting the discharge characteristic curve according to the temperature T; carrying out the continuous discharge test on the battery, real-timely detecting the current battery voltage Vt during the test process, and calculating the current surplus capacity SOCt of the battery; when the situation that the voltage Vt is discharged to the discharge voltage Vn of the preset correction point is detected, comparing the current surplus capacity SOCt and the battery capacity SOCn, if the current surplus capacity SOCt and the battery capacity SOCn are unequal, correcting the current surplus capacity SOCt as the battery capacity SOCn of the corresponding correction point, otherwise, not correcting. The method of the present invention enables the charging curve correction data needing to be stored in a battery management system to be little, is simple and fast in operation, and facilitates reducing the cost of the battery management system and applying and popularizing the battery management system.

Description

technical field [0001] The invention relates to the technical field of power management, in particular to a method for correcting SOC based on a battery discharge characteristic curve and an ampere-hour integration method. Background technique [0002] SOC (state of charge, refers to the ratio of the remaining capacity of the battery to its fully charged capacity) as an index 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, a 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 diff...

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, and the calculated SOC value has a large error

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