Method and device for monitoring insulation fault of electric automobile

Abstract

The embodiment of the invention provides a method and device for monitoring an insulation fault of an electric automobile, wherein the method for monitoring the insulation fault of the electric automobile comprises the following steps of: acquiring an insulation resistance value during a last power-off process of a vehicle of the electric automobile and storing the insulation resistance value in anonvolatile memory; reading the insulation resistance value of the vehicle in the last power-off process in each electrifying process, and determining whether the electric automobile can be electrified by using s high voltage according to whether the insulation resistance value of the vehicle in the last power-off process is lower than a second calibration threshold value, wherein, if the insulation resistance value of the vehicle in the last power-off process is lower than the second calibration threshold value, that means the insulation fault exists in the electric automobile, and the highvoltage applied on the electric automobile is prohibited; and if the insulation resistance value of the vehicle in the last power-off process is higher than the second calibration threshold value, thehigh voltage applied on the electric automobile is allowed. According to the invention, whether the high voltage can be applied to the electric automobile or not is determined, thereby avoiding unnecessary closing and opening of a battery main relay, preventing the situation that the power is immediately cut off after the high voltage is applied to the electric automobile, and effectively avoiding unintended power output.

Description

technical field [0001] The invention relates to the technical field of high-voltage safety of electric vehicles, in particular to a method and device for monitoring insulation faults of electric vehicles. Background technique [0002] In recent years, the number of motor vehicles in my country has grown rapidly, and vehicle exhaust emissions have become one of the most important sources of air pollution in major cities, seriously restricting and affecting the sustainable development of cities and people's daily life. At present, all countries and major automobile manufacturers in the world are vigorously developing hybrid electric vehicles and pure electric vehicles to replace traditional fuels with new energy sources. Therefore, hybrid electric vehicles and pure electric vehicles have good development prospects and market potential. [0003] With the rapid development of the new energy vehicle industry, the high voltage safety of new energy vehicles is increasingly concerne...

AI Technical Summary

Problems solved by technology

At present, for the treatment of insulation faults of new energy vehicles, the insulation faults that occur during the power-off process of the vehicle have not been fully considered, and the controller has stopped diagnosing the insulation fault of the electric vehicle during the power-off process of the vehicle. If an insulation fault occurs at this time , it is impossible to prevent the electric vehicle from being powered on again by storing the insulation fault code. If the fault is not dealt with in time, there will be a situation where the high voltage power is turned on again and then the power will be cut off immediately, resulting in frequent actions of the electric vehicle battery main relay and other devices. The safety of the whole vehicle and personnel, as well as the life of some components of the vehicle are unfavorable, and the forced high-voltage power-off during driving will easily lead to the failure of the vehicle to be transferred to the maintenance point, and even cause safety accidents

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