Battery pack insulation detection alarm device and method thereof

Abstract

The invention provides an insulation detection alarm device. The insulation detection alarm device comprises an alternating current power supply, a fixed value resistor, a fixed value capacitor, a selection module, a control module and an alarm module. The alternating current power supply is used for generating an alternating current signal. One end of the alternating current power supply is grounded. One end of the fixed value resistor is connected in series with the other end of the alternating current power supply. The fixed value capacitor is used for isolating the direct current voltage of a battery pack, and is connected in series with the other end of the fixed value resistor. The selection module selectively connects the fixed value capacitor and the positive pole or negative poleof the battery pack in series. The control module is coupled to the alternating current power supply, and controls the alternating current power supply to generate an alternating current signal. The control module is coupled to the selection module, and controls the selection module to selectively connect the fixed value capacitor and the positive pole or negative pole of the battery pack in series. The control module detects the voltage of a voltage collection point between the fixed value resistor and the fixed value capacitor and calculates an accessed insulation resistance value based on the voltage value of the voltage collection point to determine whether the battery pack is in a leakage state. The control module is coupled to the alarm module and controls the alarm module to issue awarning signal in response to the leakage state.

Description

technical field [0001] The invention relates to a power system of a pure electric vehicle, in particular to an insulation detection and alarm device for a battery pack of a pure electric vehicle and a method thereof. Background technique [0002] With the aggravation of global environmental problems, pure electric vehicles, as a new energy means of transportation, fully meet the user's requirements for travel convenience and pollution-free. Because high-speed running cars require a huge amount of mechanical energy as a power source, and pure electric vehicles use power batteries to drive mechanical brakes, the existing electric vehicles have battery packs with high voltage as power systems. The frame is a good conductor of electricity. If there is a leakage in the high-voltage battery pack, the entire body will be charged, which will not only affect the operation of the vehicle but also affect the safety of users. Therefore, it is very important to perform insulation testing...

AI Technical Summary

Problems solved by technology

The balanced bridge method can only be carried out when the battery pack is not charging or discharging, and the battery pack must be connected at high voltage, which is poor in safety and practicability; the low-frequency injection method can effectively measure the insulation resistance in real time under various working conditions, and the disadvantages are: The measured resistance is the parallel equivalent value of the insulation resistance of the positive and negative poles of the battery pack to the ground, and the independent ground insulation resistance of the positive and negative poles cannot be measured separately. Moreover, when the battery pack is powered off at high voltage (such as MSD disconnected) , only one of the values ​​of the insulation resistance of the positive and negative poles of the battery pack to the ground can be measured

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