Battery charging control method of pure electric vehicle

Abstract

The invention discloses a battery charging control method for a pure electric vehicle, and the method specifically comprises the following steps that S1, a battery management system BMS controls a main negative relay to be closed based on a charging flag bit, and an HVCM controls a vehicle-mounted charger OBC to enter a current mode, i.e., controls the vehicle-mounted charger OBC to carry out thecharging at a constant current; and S2, the battery management system BMS controls the main negative relay to be disconnected based on the charging forbidding flag bit, and the HVCM controls the OBC to enter a voltage mode, that is to say, the output voltage of the OBC is the same as the output voltage of the power battery. When the main negative relay is disconnected, the OBC works in a voltage mode, the voltage of the OBC is kept consistent with the voltage of the power battery pack, and the situation that when charging is started, voltage difference exists between the power battery and theOBC, so that the main negative relay is closed to generate electric arcs, and safety is affected is avoided; When the main negative relay is closed, the OBC works in a constant-current mode, and the maximum charging efficiency and safety are guaranteed.

Description

technical field [0001] The invention belongs to the technical field of electric vehicles, and more specifically, the invention relates to a battery charging control method of a pure electric vehicle. Background technique [0002] At present, the control method for charging and powering on the power battery of pure electric vehicles is mainly for the VCU to judge whether the power battery is under the allowable charging condition through the state of the vehicle. If so, close the main positive and main negative relays to charge and power on the power battery. Then the main positive and main negative relays are prohibited from closing, waiting for the next charging and power-on command. In the prior art, when judging that the power battery is allowed to be charged, directly closing the main positive and main negative relays will cause a large voltage difference between the two ends of the relays, generate sparks, and damage the relays. Instantaneous high voltage and strong cu...

AI Technical Summary

Problems solved by technology

In the existing technology, when judging that the power battery is allowed to be charged, directly closing the main positive and main negative relays will cause a large voltage difference between the two ends of the relay, generate sparks, and damage the relay

Instantaneous high voltage and strong current will also damage the power battery and charging circuit components, reducing its service life and increasing potential safety hazards

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