Protective method and protective device of power storage battery

Abstract

The invention provides a protective method and a protective device of power storage batteries, wherein the method comprising following steps: (1) acquiring a permitted maximum value of input power of the power storage battery and acquiring a maximum value of the voltage of a battery cell in the present power storage battery; (2) determining whether a difference value between the maximum value of the voltage and a preset overvoltage threshold value is greater than zero or not, if the difference value is greater than zero, processing the difference value according to the proportional integral and differential PID control algorithm to obtain a processing result; and (3) obtaining a first power according to the maximum value of the input power and the processing result, and controlling torque of a motor according to the first power for controlling the input power of the power storage battery. According to the embodiment, by means of the protective method, when the power storage battery is subjected to overvoltage, the voltage of the battery can be quickly decreased to below the preset overvoltage threshold value through the proportional integral and differential PID control algorithm. In addition, the circuit change is smooth and steady, so that the protective method and the protective device reduce damage of the overvoltage on the battery and further prolong the service life of the battery.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a method and device for protecting a power storage battery. Background technique [0002] The power battery used in electric vehicles is composed of multiple single cells connected in series and parallel. Due to the limitation of electrochemical principles, the allowable working voltage of the single battery must be within a range. If the working voltage exceeds this voltage range during use The upper limit of the voltage range (ie overvoltage) or the lower limit of the voltage range (ie undervoltage) may cause irreversible damage to the single battery, thereby reducing the service life of the power battery. [0003] For example, if there is serious overvoltage or undervoltage during the use of the traction battery, that is, the voltage range exceeds the allowable working range, side reactions will occur inside the battery, resulting in internal short circuits, heating and othe...

AI Technical Summary

Problems solved by technology

[0004] However, the processing method in the related art has the following disadvantages: (1) For electric vehicles in pure electric mode, directly cutting off the contactor to disconnect the high-voltage circuit connection means disconnecting the energy supply of the power system, and the electric vehicle will Loss of power will cause electric vehicles to lose control and cause danger

In addition, disconnecting the power battery during the braking feedback process can well prevent the battery from overcharging, but since the drive motor is still rotating at a high speed, the no-load voltage will increase when the load power battery has been disconnected. May exceed the withstand voltage range of high-voltage electrical components

(2) Due to the ever-changing road conditions, the current changes drastically during the driving of an electric vehicle, and the highest or lowest voltage of a single battery also changes sharply. Then, the maximum available power sent by the battery management system to the VMS or charger changes Vigorous, in the control of the vehicle, it is easy to cause shaking and affect the comfort of the vehicle

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