Electric vehicle insulation fault detection method and device

Abstract

The invention discloses an electric vehicle insulation fault detection method and device, and the method comprises the steps: acquiring a current working mode of an electric vehicle, and determining ato-be-detected system needing to detect an insulation fault based on the working mode; acquiring an insulation resistance value of the to-be-detected system; comparing the insulation resistance valuewith a preset threshold value corresponding to the current working mode of the electric automobile, and judging whether an insulation fault occurs or not to obtain a first judgment result; if the first judgment result is that the insulation fault occurs, further judging whether the insulation fault is a serious fault or a slight fault to obtain a second judgment result; and selecting a corresponding fault processing measure for processing based on the second judgment result. According to the invention, whether the electric vehicle has the insulation fault at present and the severity degree ofthe insulation fault can be determined according to a preset threshold value corresponding to the current working mode of the electric vehicle, so that different fault processing measures can be taken for processing.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of electric vehicles, in particular to a method and device for detecting insulation faults of electric vehicles. Background technique [0002] Existing electric vehicle insulation detection methods mostly adopt the dual-resistor method recommended by the national standard, which is generally implemented in the BMS (Battery Management System). The insulation resistance value is calculated by the voltage change between the positive and negative poles of the battery before and after parallel connection; this method has three limitations. It is impossible to distinguish the specific faulty device. The current general practice is to adopt the same fault alarm and processing strategy for all fault situations. [0003] Moreover, the current electric vehicle insulation detection method does not consider the DC charging status. During the DC charging process, the BMS monitors the insulation of ...

AI Technical Summary

Problems solved by technology

[0002] Existing electric vehicle insulation detection methods mostly adopt the dual-resistor method recommended by the national standard, which is generally implemented in the BMS (Battery Management System). The insulation resistance value is calculated by the voltage change between the positive and negative poles of the battery before and after parallel connection; this method has three limitations, one is that the battery power supply must be present to detect; the other is that if the insulation performance of the entire system is tested, It is impossible to distinguish the specific faulty device. The current general practice is to adopt the same fault alarm and processing strategy for all fault situations

[0003] Moreover, the current electric vehicle insulation detection method does not consider the DC charging status. During the DC charging process, the BMS monitors the insulation of the entire system. Record this threshold, resulting in failure to start the next time the power is turned on, that is, the failure of the entire vehicle function due to external charging pile problems

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