Method for forecasting turn-off time of contactor by battery management system of electric automobile

Abstract

The invention discloses a method for forecasting the turn-off time of a contactor by a battery management system of an electric automobile. The method comprises the following steps that: a, the battery management system detects a fault that a power battery generates in real time and sets the overflow time of a turn-off timer of the contactor; and b, the overflow time of the turn-off timer of the contactor is sent to an entire-automobile CAN (controller area network), and the entire-automobile CAN controls each node to complete current reduction response within the overflow time of the timer of the contactor. The method has the advantages that: 1, by sending the forecasted turn-off time of the contactor and the fault information of the power battery to the entire-automobile CAN, the battery management system notifies and requires relevant nodes such as an entire-automobile controller and a motor controller to complete the current reduction response within estimated time in advance; the load current in a turn-off process is decreased; and the service life of the contactor is prolonged; and 2, the risk of generating a serious safety problem is reduced.

Description

technical field [0001] The invention relates to a method for controlling a contactor of an electric vehicle so as to improve the service life of the contactor. Background technique [0002] The battery management system is a necessary means to ensure the safe operation of new energy vehicle power batteries. Generally, it should have the functions of real-time detection of power battery fault information, control of contactor action, detection of power battery voltage, current and temperature, and estimation of current SOC. A common battery management system sends the fault information of the battery to the vehicle controller first when some faults occur in the power battery. current response. At the same time, the battery management system directly disconnects the contactor after waiting for a predefined period of time. [0003] Insufficiency and defects: In the above common processing methods, the battery management system does not clearly put forward the time requi...

AI Technical Summary

Problems solved by technology

[0003] Insufficiency and defects: In the above common processing methods, the battery management system does not clearly put forward the time requirement for the load to reduce the current

After the battery management system waits for a predefined period of time, without taking into account the actual completion of the load drop current, the load current when the contactor opens may not be less than the open allowable value, increasing the risk of damage or sticking of the contactor contacts , accelerates the aging of the contactor

At the same time, the fault information of the power battery needs to be processed by the vehicle controller before the motor controller and other load nodes are required to respond to the current reduction, which prolongs the fault processing time and increases the risk of serious safety problems.