Discharging method and device of power battery, battery management system and electric vehicle

Abstract

The invention discloses a discharging method and device of a power battery, a battery management system and an electric vehicle. The method comprises the steps that a current charge state and the current temperature of the power battery are collected, and the maximum discharging power of the power battery is obtained; the minimum monomer voltage of the power battery is detected, and whether the minimum monomer voltage is less than a first preset threshold or not is judged; if the minimum monomer voltage is less than the first preset threshold, the maximum discharging power is corrected to a preset power value until the minimum monomer voltage is larger than a second preset threshold, and correcting is stopped, wherein the second preset threshold is larger than the first preset threshold. According to the method, the maximum discharging power of the power battery can be corrected according to the minimum monomer voltage of the power battery, so that the situation of faults caused by overdischarging and voltage shortage of the power battery is avoided, the using efficiency of the battery is improved, the service life of the battery is prolonged, reliability of the battery is ensuredeffectively, and the method is simple and easy to achieve.

Description

technical field [0001] The invention relates to the technical field of power batteries, in particular to a power battery discharge method, device, battery management system and electric vehicle. Background technique [0002] At present, the power battery is used as an energy storage device for electric vehicles, which makes it have high requirements for consistency and SOC (State of Charge, state of charge) estimation deviation. In the related art, SOC correction at the charging end is performed through the SOC estimation based on the ampere-hour integral, so as to effectively ensure the consistency of the battery and reduce the deviation of the SOC estimation. [0003] However, there is no correction at the discharge end, and the discharge power of the power battery system is based on the SOC and temperature look-up table. Once the power battery system is not corrected during the discharge process, the battery consistency will become worse as the power battery ages. Poor, ...

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Problems solved by technology

[0003] However, there is no correction at the discharge end, and the discharge power of the power battery system is based on the SOC and temperature look-up table. Once the power battery system is not corrected during the discharge process, the battery consistency will become worse as the power battery ages. Poor, resulting in a deviation between the actual SOC and the estimated SOC of the battery, and further long-term deviations lead to an increasing accumulation of SOC errors, and at this time, wrong SOC or SOC correction jumps and excessive discharge power will reduce battery efficiency, or even Reducing the service life of the battery needs to be solved urgently

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