Method and device for determining open-circuit voltage of battery and charging pile

Abstract

The invention provides a method for determining the open-circuit voltage of a battery. The method comprises the following steps of acquiring a predicted open-circuit voltage of the battery; performing constant-current charging on the battery, and measuring a first voltage of the battery during constant-current charging; when the first voltage meets a first threshold condition, performing forward pulse charging on the battery; measuring a second voltage of the battery during forward pulse charging, and determining a rise rate of the second voltage; and determining the voltage measured when the rising rate meets a second threshold condition as the open-circuit voltage of the battery. According to the method provided by the invention, concentration difference between the reactant concentration near the surface of the electrode and the solution body concentration can be quickly counteracted through a two-stage charging mode, and the stable open-circuit voltage can be quickly obtained.

Description

technical field [0001] The invention belongs to the technical field of electric vehicles, and in particular relates to a method, a device and a charging pile for determining the open-circuit voltage of a battery. Background technique [0002] The available state of charge (State of Charge, SOC) of the remaining charge in the battery is a very important parameter during the operation of the electric vehicle. For pure electric vehicles, SOC data is the main basis for preventing battery overcharge and overdischarge. For hybrid vehicles, battery pack SOC data is the main basis for vehicle control strategies. [0003] The open-circuit voltage of the battery is an important parameter of the current mainstream SOC algorithm. However, since the vehicle often needs to be charged as soon as possible after parking, there is not enough rest time to obtain a stable open-circuit voltage, which brings great difficulties to the SOC algorithm. [0004] Although there are currently methods f...

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Problems solved by technology

[0003] The open circuit voltage of the battery is an important parameter of the current mainstream SOC algorithm, but because the vehicle often needs to be charged as soon as possible after parking, there is not enough rest time to obtain a stable open circuit voltage, which brings great difficulties to the SOC algorithm

[0004] Although there are currently methods for estimating the open circuit voltage, there are certain errors in the estimated open circuit voltage. Therefore, there is an urgent need for a method to accurately obtain the open circuit voltage to obtain accurate SOC data.

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