Voltage acquisition method of battery pack and electric vehicle

Abstract

The invention relates to the technical field of electric vehicles, in particular to a voltage acquisition method of a battery pack and an electric vehicle, and the acquisition method comprises the following steps that: S1, a resistance value R of a conductor electrically connected between a first module and a second module is determined; s2, a BMS collects the negative electrode potential of the single body located at the end of the first module, and the BMS collects the negative electrode potential of the single body located at the end of the adjacent second module; s3, when the battery pack is charged, the BMS collects the charging current I of the battery pack to obtain the charging voltage U1 of the single body at the end of the first module; and when the battery pack is discharged, the BMS collects the discharge current I' of the battery pack to obtain the discharge voltage U1' of the single body at the end of the first module. The sampling precision of the voltage of the single body can be improved, the consistency of the battery pack is improved, and therefore the use performance of the battery pack is improved, and the service life of the battery pack is prolonged.

Description

technical field [0001] The invention relates to the technical field of electric vehicles, in particular to a battery pack voltage collection method and an electric vehicle. Background technique [0002] The internal cell voltage of the battery pack of an electric vehicle is generally sampled and monitored by the BMS (BATTERY MANAGEMENT SYSTEM). Usually, there are sampling lines connected to the positive and negative sides of the cell. The BMS identifies the voltage of the cell through the potential difference between the sampling lines. body voltage. The adjacent modules in the battery pack are electrically connected by conductors, and the voltage sampling of the cells located at the ends of the modules generally includes the electrical connection of the conductors between the modules. Since the electrical connection using a conductor is not a perfect conductor, the conductor has a certain resistance value. When the battery pack has a working current, the conductor at the e...

AI Technical Summary

Problems solved by technology

Since the electrical connection using a conductor is not a perfect conductor, the conductor has a certain resistance value. When the battery pack has a working current, the conductor at the electrical connection position will have a partial voltage, which will affect the voltage sampling accuracy of the monomer at the end of the module. As a result, the voltage consistency of the single cells identified by the BMS is poor, which can easily lead to an alarm if the voltage difference is too large, and affect the performance of the overall battery pack.

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