WO2022007822A1

WO2022007822A1 - Electric vehicle insulation fault detection method and device

Info

Publication number: WO2022007822A1
Application number: PCT/CN2021/104873
Authority: WO
Inventors: 于春洋; 许立超; 荣常如; 刘轶鑫; 马腾翔
Original assignee: 中国第一汽车股份有限公司
Priority date: 2020-07-08
Filing date: 2021-07-07
Publication date: 2022-01-13
Also published as: CN111751686B; CN111751686A

Abstract

An electric vehicle insulation fault detection method and device. The method comprises: obtaining a current working mode of an electric vehicle, and on the basis of the working mode, determining a system to be detected requiring insulation fault detection (S101); acquiring an insulation resistance value of the system (S102); comparing the insulation resistance value with a preset threshold corresponding to the current working mode of the electric vehicle, and determining whether an insulation fault occurs to obtain a first determining result (S103); if the first determining result is that the insulation fault occurs, further determining whether the insulation fault is a serious fault or a slight fault to obtain a second determining result (S104); and on the basis of the second determining result, selecting a corresponding fault processing measure for processing (S105). The method and device can determine the severity degree of an insulation fault occurring to a system to be detected, so that different fault processing measures can be taken for accurate processing.

Description

Electric vehicle insulation fault detection method and device

This application claims the priority of the Chinese patent application with an application date of July 8, 2020 and an application number of 202010651786.9, the entire contents of which are incorporated into this application by reference.

technical field

The present application relates to the technical field of electric vehicles, for example, to a method and device for detecting insulation faults of electric vehicles.

Background technique

In the related art, the electric vehicle insulation detection method mostly adopts the double-resistance method recommended by the national standard, which is generally implemented in the BMS (BATTERY MANAGEMENT SYSTEM, battery management system). This method connects the known resistance between the positive and negative electrodes of the battery and the body ground in parallel. The insulation resistance value is calculated by the voltage change between the positive and negative electrodes of the battery before and after the parallel connection to the ground; this method has three limitations, one is that it can only be detected when there is a battery power supply; The insulation performance of the system cannot distinguish specific faulty components. The general practice is to use the same fault alarm and processing strategy for all fault conditions.

In addition, the electric vehicle insulation detection method in the related art also does not consider the DC charging condition. During the DC charging process, the BMS monitors the insulation of the entire system. The BMS records this threshold, which will cause the system to fail to start the next time it is powered on, that is, the vehicle function will fail due to external charging pile problems.

SUMMARY OF THE INVENTION

The present application provides a method and device for detecting an insulation fault of an electric vehicle, which can determine whether an insulation fault currently occurs in an electric vehicle and the severity of the insulation fault according to a preset threshold set corresponding to the current working mode of the electric vehicle, thereby The technical effect of taking different troubleshooting measures to deal with.

An embodiment provides a method for detecting an insulation fault of an electric vehicle, including: acquiring a current working mode of an electric vehicle, and determining a system to be detected that needs to detect an insulation fault based on the working mode; collecting the insulation resistance value of the system to be detected ; Compare the insulation resistance value with the preset threshold value corresponding to the current working mode of the electric vehicle, determine whether an insulation fault has occurred, and obtain a first judgment result; when the first judgment result is that an insulation fault has occurred In the case of , determine that the insulation fault is the first fault level or the second fault level, and obtain a second judgment result; and

Corresponding fault handling measures are selected for processing based on the second judgment result.

In one embodiment, the acquiring the current working mode of the electric vehicle includes:

After the controller of the battery management system of the electric vehicle is started, the state of the main relay, the state of the charging relay and the connection state of the charging gun are obtained; when the main relay is disconnected, the charging relay is disconnected and the charging gun is not connected Under the condition that the current working mode of the electric vehicle is the battery mode; when the main relay is closed, the charging relay is disconnected and the charging gun is not connected, the current working mode of the electric vehicle is the vehicle mode ; and when the main relay is closed, the charging relay is closed and the charging gun is connected, the current working mode of the electric vehicle is a fast charging mode.

In one embodiment, the determining, based on the working mode, that the system to be detected needs to be detected for insulation faults includes:

When the current operating mode of the electric vehicle is the battery mode, the system to be detected is a power battery;

When the current operating mode of the electric vehicle is the vehicle mode, the system to be detected is a vehicle high-voltage system; and

In the case that the current working mode of the electric vehicle is the fast charging mode, the system to be detected is a high-voltage system of the whole vehicle and a charging pile system.

In one embodiment, when the current mode of the electric vehicle is the battery mode, the insulation resistance value is compared with a preset threshold corresponding to the current working mode of the electric vehicle, and the judgment is made whether An insulation fault occurs, and obtaining a first judgment result includes: comparing the insulation resistance value with a first preset threshold value, and in the case that the insulation resistance value is less than the first preset threshold value, the first judgment result is: An insulation fault occurs; in the case that the first judgment result is an insulation fault, judging that the insulation fault is the first fault level or the second fault level, and obtaining the second judgment result includes:

The insulation resistance value is compared with a second preset threshold value, and in the case that the insulation resistance value is less than the second preset threshold value, the second judgment result is the second failure level, wherein the first 2. The preset threshold is less than the first preset threshold;

When the insulation resistance value is greater than the second preset threshold value and less than the first preset threshold value, the second judgment result is the first failure level.

In one embodiment, when the current working mode of the electric vehicle is the vehicle mode, the insulation resistance value is compared with a preset threshold value corresponding to the current working mode of the electric vehicle to determine whether the occurrence of Insulation failure, obtaining a first judgment result includes: comparing the insulation resistance value with a third preset threshold value, and in the case that the insulation resistance value is less than the third preset threshold value, the first judgment result is occurrence of occurrence Insulation fault; when the first judgment result is that an insulation fault occurs, judging that the insulation fault is the first fault level or the second fault level, and obtaining the second judgment result includes: comparing the insulation resistance value with the The fourth preset threshold value is compared, and in the case that the insulation resistance value is smaller than the fourth preset threshold value, the second judgment result is that the insulation fault is a second fault level, wherein the fourth preset threshold value is The threshold is set to be less than the third preset threshold; when the insulation resistance value is greater than the fourth preset threshold and less than the third preset threshold, the second judgment result is the first failure level.

In one embodiment, when the current working mode of the electric vehicle is the fast charging mode, the insulation resistance value is compared with a preset threshold corresponding to the current working mode of the electric vehicle, and it is determined whether the occurrence of Insulation failure, obtaining a first judgment result includes: comparing the insulation resistance value with a fifth preset threshold, and in the case that the insulation resistance value is less than the fifth preset threshold, the first judgment result is occurrence Insulation fault; when the first judgment result is that an insulation fault occurs, judging that the insulation fault is the first fault level or the second fault level, and obtaining the second judgment result includes: comparing the insulation resistance value with the The sixth preset threshold value is compared, and in the case that the insulation resistance value is less than the sixth preset threshold value, the second judgment result is the second failure level; when the insulation resistance value is greater than the sixth preset threshold value When the threshold is set and is smaller than the fifth preset threshold, the second judgment result is the first failure level.

In an embodiment, when the current working mode of the electric vehicle is the battery mode or the vehicle mode, the selecting corresponding fault handling measures based on the second judgment result for processing includes: in the second judgment result: In the case of the second fault level, select at least one of the following fault handling measures: prohibit charging, prohibit power-on and meter prompts; and when the second judgment result is the first fault level, select the following faults At least one of the actions: Display power and meter prompts.

When the current working mode of the electric vehicle is the fast charging mode, the selecting a corresponding fault handling measure based on the second judgment result for processing includes: when the second judgment result is the second fault level, Terminate charging, but do not latch the fault code or save the insulation resistance value; and if the second judgment result is the first fault level, return to the user "This charging pile insulation is abnormal, please use with care" prompt information.

In one embodiment, when the current operating mode of the electric vehicle is the battery mode or the vehicle mode, and the second judgment result is the second failure level, the method further includes: storing the insulation The fault flag of the fault; and when the system to be detected is powered on again, the insulation fault is reported to the vehicle controller, and the working mode when the fault occurs is stored in the fault snapshot.

In the case that the second judgment result is the first fault level, the method further includes: storing the fault code of the insulation fault; and storing the working mode when the fault occurs in the fault snapshot, and storing the fault code in the to-be-detected When the system is powered on again, it is re-detected whether the insulation fault exists.

In an embodiment, when the current operating mode of the electric vehicle is the battery mode, after selecting the corresponding fault handling measures based on the second judgment result, the method further includes: an insulation fault detection process. Whether it is completed, when the insulation fault detection process is completed, it enters the sleep state, and when the insulation fault detection process is not completed, the fault detection state is maintained.

An embodiment of the present application also provides an electric vehicle insulation fault detection device, including:

A determination module, configured to acquire the current working mode of the electric vehicle, and to determine a system to be detected that needs to detect insulation faults based on the working mode; an acquisition module, configured to collect the insulation resistance value of the system to be detected; a first judgment module, It is set to compare the insulation resistance value with a preset threshold corresponding to the current working mode of the electric vehicle, to judge whether an insulation fault occurs, and to obtain a first judgment result; the second judgment module is set to In the case where the judgment result is that an insulation fault occurs, judge that the insulation fault is a first fault level or a second fault level, and obtain a second judgment result; and a processing module, configured to select a corresponding fault treatment based on the second judgment result measures to deal with.

Description of drawings

1 is a flowchart of a method for detecting an insulation fault of an electric vehicle provided by an embodiment of the present application;

2 is a structural diagram of a system to be detected provided in a three-dimensional manner according to an implementation of the present application;

3 is a schematic diagram of mutual conversion of each working mode of an electric vehicle provided by an embodiment of the present application;

4 is a timing diagram of each working mode of an electric vehicle provided by an embodiment of the present application;

FIG. 5 is a structural diagram of an electric vehicle insulation fault detection device according to an embodiment of the present application.

detailed description

The terms "first", "second" and the like in the description and claims of the present application and the drawings are used to distinguish different objects, rather than to limit a specific order. Each of the following embodiments of the present application may be executed independently, and each embodiment may also be executed in combination with each other, which is not specifically limited by the embodiments of the present application.

FIG. 1 is a flowchart of a method for detecting an insulation fault of an electric vehicle provided by an embodiment of the present application.

As shown in FIG. 1 , the method for detecting an insulation fault of an electric vehicle specifically includes the following steps:

In S101, the current working mode of the electric vehicle is acquired, and based on the working mode, a system to be detected that needs to detect an insulation fault is determined.

In one embodiment, the working modes of the electric vehicle include battery mode, vehicle mode and fast charging mode; when the working mode is the battery mode, the insulation resistance value of the power battery needs to be detected, that is, the system to be detected is the power battery; When the mode is the vehicle mode, the insulation resistance value of the vehicle high-voltage system needs to be detected, that is, the system to be detected is the vehicle high-voltage system; when the working mode is the fast charging mode, the insulation resistance value of the vehicle high-voltage system and the charging pile system needs to be detected. , that is, the system to be detected is the vehicle high-voltage system and the charging pile system.

In one embodiment, in S101, acquiring the current working mode of the electric vehicle specifically includes the following steps:

In S1, after the controller of the battery management system of the electric vehicle is started, the state of the main relay, the state of the charging relay and the connection state of the charging gun are acquired.

In one embodiment, the BMS may determine the current working mode of the electric vehicle according to the state of the main relay, the state of the charging relay, and the connection state of the charging gun. FIG. 2 is a structural diagram of a system to be detected provided by an embodiment of the present application, wherein the main relay includes a main positive relay and a main negative relay, and the charging relay includes a charging positive relay and a charging negative relay. It should be noted that in FIG. 2 The position of the charging relay shown is for illustration only, and the charging relay can also be directly connected to the power battery terminal. FIG. 3 is a schematic diagram of mutual conversion of each working mode of an electric vehicle according to an embodiment of the present application.

In S2, if the main relay is disconnected, the charging relay is disconnected, and the charging gun is not connected, the electric vehicle is currently in battery mode.

Referring to Figure 2 and Figure 3, when the main relay is disconnected, the charging relay is disconnected and the charging gun is not connected, that is, when the whole vehicle is powered off, the insulation resistance value detected by the BMS is the insulation resistance value of the battery itself, and the electric vehicle is in the battery state. model.

In S3, if the main relay is closed, the charging relay is disconnected, and the charging gun is not connected, the electric vehicle is currently in the vehicle mode.

Referring to Figure 2 and Figure 3, when the main relay is closed, the charging relay is disconnected and the charging gun is not connected, that is, when the vehicle is started (the relay is closed and the high voltage is powered on), the BMS detects the insulation resistance of the entire high voltage system. The electric vehicle is in full vehicle mode.

In S4, if the main relay is closed, the charging relay is closed, and the charging gun is connected, the electric vehicle is currently in the fast charging mode.

Referring to Figure 2 and Figure 3, when the main relay is closed, the charging relay is closed, and the charging gun is connected, the BMS detects the common insulation resistance of the vehicle's high-voltage system and the charging pile system. At this time, the electric vehicle is in fast charging mode.

In one embodiment, in S101, determining the system to be detected that needs to detect the insulation fault based on the working mode includes: if the current mode of the electric vehicle is the battery mode, the system to be detected is the power battery; if the current mode of the electric vehicle is the whole vehicle If the current mode of the electric vehicle is the fast charging mode, the system to be detected is the high-voltage system of the whole vehicle and the charging pile system.

In one embodiment, referring to FIG. 3 , if the electric vehicle is currently in the battery mode, the insulation resistance value detected by the BMS is the insulation resistance value of the battery itself, and the system to be detected is the power battery; if the electric vehicle is currently in the vehicle mode, The BMS detects the insulation resistance of the entire high-voltage system, and the system to be detected is the vehicle's high-voltage system; if the electric vehicle is in fast charging mode, the BMS detects the insulation resistance of the vehicle's high-voltage system and the charging pile system. value, the system to be detected is the vehicle high-voltage system and the charging pile system.

In S102, the insulation resistance value of the system to be detected is collected. After the current working mode of the electric vehicle is determined, and the corresponding system to be detected is determined based on the working mode, the insulation resistance value of the system to be detected is collected to judge whether the electric vehicle has an insulation fault based on the collected insulation resistance value.

In S103, the insulation resistance value is compared with a preset threshold value corresponding to the current working mode of the electric vehicle to determine whether an insulation fault occurs, and a first determination result is obtained.

In S104, when the first judgment result is that an insulation fault occurs, it is judged whether the insulation fault is the first fault level or the second fault level, and a second judgment result is obtained.

In S105, a corresponding fault handling measure is selected for processing based on the second judgment result.

In one embodiment, for the determination of the preset threshold value, from the perspective of the battery pack, the normal resistance value is generally above 20MΩ. Once the resistance value is less than 1MΩ, it can be considered that there is a relevant abnormal situation, and should be carried out. Therefore, in the battery mode, the threshold standard can be selected as 5MΩ and 1MΩ; from the perspective of personnel electric shock, the threshold standard in related technologies is generally based on the national standard "18384.3-2015 Electric Vehicle Safety Requirements Part 3: Personnel Electric Shock Protection ", so in the vehicle mode, you can select two threshold standards of 100Ω/V and 500Ω/V, and then consider the detection accuracy and set different preset thresholds. In an embodiment of the present application, different preset thresholds are set according to different working modes, so as to achieve refined control in a more appropriate manner, achieve early warning, and ensure the safety of electric vehicles.

In one embodiment, according to different preset thresholds set in different working modes, it is first judged whether an insulation fault occurs in this working mode, and the first judgment result is obtained. When the first judgment result is that an insulation fault has occurred, based on the preset threshold, it is further judged whether the insulation fault occurred in the working mode is the first fault level or the second fault level, a second judgment result is obtained, and the selection is made according to the second judgment result. Corresponding fault measures are processed, wherein the first fault level is a minor fault, the second fault level is a serious fault, and the second fault level is greater than the first fault level.

In the present application, by setting different preset thresholds of insulation resistance values in different working modes of the electric vehicle, it is possible to determine whether an insulation fault currently occurs in the electric vehicle according to the preset threshold value corresponding to the current working mode of the electric vehicle, and whether the electric vehicle has an insulation fault. The severity of the insulation fault, so as to take different fault handling measures to deal with the technical effect.

In one embodiment, when the working mode is the battery mode or the vehicle mode, in S105, selecting a corresponding fault handling measure based on the second judgment result for processing includes: if the second judgment result is that the insulation fault is a serious fault, selecting Take at least one of the following fault handling measures: prohibit charging, prohibit power-on or meter prompt; if the second judgment result is that the insulation fault is the first fault level, choose at least one of the following fault handling measures for processing: display power or instrument prompt;

When the working mode is the fast charging mode, step S105, selecting corresponding fault handling measures based on the second judgment result for processing. Specifically, the process includes: if the second judgment result is the first fault level, terminating the charging, but not latching the fault code. The insulation resistance value is also not saved; if the second judgment result is the first fault level, the prompt message "This charging pile insulation is abnormal, please use it with care" will be returned to the user.

In one embodiment, when the working mode is the battery mode or the vehicle mode, if the second judgment result is the second fault level, the electric vehicle insulation fault detection method further includes the steps of: storing the fault flag of the insulation fault; When the system to be tested is powered on again, the insulation fault will be reported to the vehicle controller, and the working mode when the fault occurs is stored in the fault snapshot. If the second judgment result is the first fault level, the electric vehicle insulation fault detection method further includes the following steps: storing the fault code of the insulation fault; Re-detect the presence of insulation faults when electrifying.

In an embodiment of the present application, different preset thresholds may be set according to different working modes, and then different fault handling measures may be selected for processing according to the severity of insulation faults occurring in different working modes.

In one embodiment, when the working mode is the battery mode or the vehicle mode, if the second judgment result is the second fault level, then select fault handling measures such as prohibition of charging, prohibition of power-on or instrument prompts for processing. In addition, The fault flag of the insulation fault is also saved in the non-volatile memory. When the system to be detected is powered on next time, the BMS will report the insulation fault to the vehicle controller, and store the working mode when the fault occurs in the fault snapshot. , Serious faults must be checked and eliminated by professional maintenance personnel, and the fault code can be cleared with equipment (such as a diagnostic instrument) before recovery.

When the working mode is the battery mode or the vehicle mode, if the second judgment result is the first fault level, the fault handling measures such as display power and meter prompts will be selected for processing. In addition, the fault code will be saved and the historical fault will not be reported. , and record the working mode at the moment of the fault in the fault snapshot, which is convenient for after-sales troubleshooting, and re-detects whether the insulation fault exists when the system to be tested is powered on again.

When the working mode is the fast charging mode, if the second judgment result is the second fault level, the fault handling measures for terminating the charging are carried out, but the fault code is not latched and the insulation resistance value is not saved; if the second judgment result is the first If the fault level is high, the prompt message "This charging pile is abnormally insulated, please use it with care" will be returned to the user, and the working mode at the time of the fault will be recorded in the fault snapshot. This fault code is only stored for after-sales troubleshooting. When the car is powered on, it does not report the historical fault, but re-detects whether the insulation fault exists.

In one embodiment, when the working mode is the battery mode, in S103, the insulation resistance value is compared with a preset threshold value corresponding to the current working mode of the electric vehicle to determine whether an insulation fault has occurred, and obtaining the first judgment result includes: The insulation resistance value is compared with the first preset threshold value, and if the insulation resistance value is less than the first preset threshold value, the first judgment result is that an insulation fault occurs;

In S104, if the first judgment result is that an insulation fault has occurred, then judging whether the insulation fault is the first fault level or the second fault level, and obtaining the second judgment result includes: comparing the insulation resistance value with the second preset threshold, if the insulation If the resistance value is less than the second preset threshold value, the second judgment result is the second fault level, wherein the second preset threshold value is less than the first preset threshold value; if the insulation resistance value is greater than the second preset threshold value and less than the first preset value threshold, the second judgment result is the first failure level.

In one embodiment, in the battery mode, the two-level insulation fault preset threshold is set, which can be set according to the insulation resistance value of the power battery in an abnormal state, such as considering the insulation state when the harness is worn or the battery pack enters water. Wait. The first preset threshold R1 may be set to 5MΩ, and the second preset threshold R2 may be set to 1MΩ.

Compare the collected insulation resistance value of the power battery with the first preset threshold value R1, if it is greater than the first preset threshold value R1, the first judgment result is that no insulation fault has occurred; if the insulation resistance value is less than the first preset threshold value R1, the first judgment result is that an insulation fault occurs, and it is judged whether the insulation fault is the first fault level or the second fault level.

Compare the collected insulation resistance value of the power battery with the second preset threshold value R2. If the insulation resistance value is less than the second preset threshold value R2, the second judgment result is the second failure level. It should be noted that, in order to ensure The accuracy of the detection needs to be compared and confirmed for three cycles, that is, the insulation resistance value is repeatedly collected and compared with the preset threshold value, and the final detection result is obtained after repeating three times; when the second judgment result is the second fault level, carry out Troubleshooting such as prohibition of charging, prohibition of power-on or instrument prompts, in addition, the fault flag of the insulation fault needs to be saved in the non-volatile memory, and the fault will be reported by the BMS when the system to be tested is powered on next time. Vehicle controller, and record the battery mode at the moment of failure in the failure snapshot. It should be noted that the verification fault must be checked and eliminated by professional maintenance personnel, and the fault code can be cleared with equipment (such as a diagnostic instrument) before recovery.

If the insulation resistance value is greater than the second preset threshold value R2 and less than the first preset threshold value R1 at this time, that is, between R1 and R2, and the detection results are consistent after three cycles of confirmation, the second judgment result is: The first fault level, at this time, it is necessary to perform fault processing such as limiting power or meter prompts, but the result is that the first fault level only saves the fault code, and does not need to save the fault identification in the non-volatile memory, and does not need to report. For historical faults, it is only necessary to record the battery mode at the time of the fault in the fault snapshot, which is convenient for after-sales troubleshooting, and the insulation fault can be re-detected when the system to be tested is powered on next time.

In one embodiment, when the working mode is the vehicle mode, in S103, the insulation resistance value is compared with a preset threshold value corresponding to the current working mode of the electric vehicle to determine whether an insulation fault occurs, and the first judgment result is obtained. The method includes: comparing the insulation resistance value with a third preset threshold value, and if the insulation resistance value is smaller than the third preset threshold value, the first judgment result is that an insulation fault occurs.

In S104, if the first judgment result is that an insulation fault has occurred, then judging whether the insulation fault is the first fault level or the second fault level, and obtaining the second judgment result includes: comparing the insulation resistance value with the fourth preset threshold, if the insulation If the resistance value is less than the fourth preset threshold value, the second judgment result is that the insulation fault is the second fault level, wherein the fourth preset threshold value is less than the third preset threshold value; if the insulation resistance value is greater than the fourth preset threshold value and less than the third preset threshold value Three preset thresholds, the second judgment result is the first failure level.

In one embodiment, in the vehicle mode, two-level insulation fault preset thresholds are set. The preset thresholds in this mode can be based on the national standard of 100Ω/V and 500Ω/V two threshold standards, plus the detection accuracy. For setting, for example, for a 400V BMS, the third preset threshold R3 can be set to 270kΩ, and the fourth preset threshold R4 can be set to 50kΩ.

Compare the collected insulation resistance value of the high-voltage system of the whole vehicle with the third preset threshold R3, if it is greater than the third preset threshold R3, the first judgment result is that no insulation fault has occurred; if the insulation resistance value is less than the third preset threshold R3 If the threshold value R3 is set, the first judgment result is that an insulation fault occurs, and it is judged whether the insulation fault is the first fault level or the second fault level.

Compare the collected insulation resistance value of the high-voltage system of the whole vehicle with the fourth preset threshold R4. If the insulation resistance value is smaller than the fourth preset threshold R4 at this time, and the detection results are consistent after three cycles of confirmation, then The second judgment result is the second fault level; at this time, it is necessary to carry out fault processing such as prohibition of charging, prohibition of power-on, or instrument prompts. When the detection system is powered on again, the BMS reports the fault to the vehicle controller, and records the battery mode at the time of the fault in the fault snapshot. It should be noted that the verification fault must be checked and eliminated by professional maintenance personnel, and the fault code can be cleared with equipment (such as a diagnostic instrument) before recovery.

If the insulation resistance value is greater than the fourth preset threshold R4 and less than the third preset threshold R3 at this time, that is, between R3 and R4, and the detection results remain the same after three cycles of confirmation, the second judgment result is: The first fault level, at this time, it is necessary to perform fault processing such as limiting power and meter prompts, but only the fault code is saved for minor faults, and the fault identification does not need to be stored in the non-volatile memory, nor does it need to report historical faults. It is necessary to record the battery mode at the time of the fault in the fault snapshot, so as to facilitate after-sales troubleshooting, and re-detect whether the insulation fault exists the next time the vehicle is powered on.

In one embodiment, when the working mode is the fast charging mode, in S103, the insulation resistance value is compared with a preset threshold value corresponding to the current working mode of the electric vehicle, to judge whether an insulation fault has occurred, and obtaining the first judgment result includes: : the insulation resistance value is compared with the fifth preset threshold value, and if the insulation resistance value is less than the fifth preset threshold value, the first judgment result is that an insulation fault occurs;

In S104, if the first judgment result is that an insulation fault has occurred, then judging whether the insulation fault is the first fault level or the second fault level, and obtaining the second judgment result includes: comparing the insulation resistance value with the sixth preset threshold, if the insulation If the resistance value is less than the sixth preset threshold, the second judgment result is the second failure level; if the insulation resistance value is greater than the sixth preset threshold and smaller than the fifth preset threshold, the second judgment result is the first failure level.

In one embodiment, in the fast charging mode, that is, when the electric vehicle is DC charged, the preset thresholds for insulation faults are also set to two levels, that is, the fifth preset threshold R5 and the sixth preset threshold R6.

Compare the collected insulation resistance value in the high-voltage system of the whole vehicle and the charging pile system with the fifth preset threshold R5, if it is greater than the fifth preset threshold R5, the first judgment result is that no insulation fault has occurred; if the insulation resistance If the value is smaller than the fifth preset threshold R5, the first judgment result is that an insulation fault occurs, and it is judged whether the insulation fault is the first fault level or the second fault level.

The collected insulation resistance value is compared with the sixth preset threshold value R6, if the insulation resistance value is reduced to be greater than the sixth preset threshold value R6 and less than the fifth preset threshold value R5, the second judgment result is the first failure level, The battery management system BMS prompts the user: "This charging pile has abnormal insulation, please use it with care", and records the working mode at the time of the fault in the fault snapshot. This fault code is only stored for after-sales troubleshooting, and the next time the vehicle is powered on Instead of reporting historical faults, re-detect whether the insulation fault exists.

If the insulation resistance value is less than the sixth preset threshold R6, the second judgment result is the second fault level, and the BMS performs the fault processing of terminating the charging, but does not latch the fault code or save the insulation resistance value, that is, the fault needs to be professionally processed. After the maintenance personnel have checked and eliminated the fault, they can use the equipment (such as a diagnostic instrument) to clear the fault code before recovery, and will not re-detect whether the insulation fault exists the next time the vehicle is powered on.

In one embodiment, when the working mode is the battery mode, in S105, after selecting corresponding fault handling measures based on the second judgment result for processing, the electric vehicle insulation fault detection method further includes: detecting whether the insulation fault detection process is completed, If it is completed, it will enter the sleep state, and if it is not completed, it will keep the fault detection state.

FIG. 4 is a timing diagram of multiple working modes of an electric vehicle provided by an embodiment of the present application.

In one embodiment, since the insulation fault detection takes a long time, in order to ensure that the insulation fault detection process can still be successfully completed after the high voltage of the electric vehicle is powered off, the BMS will also ensure that the insulation resistance value of the power battery is correctly detected before performing the detection. Dormancy, refer to Figure 4, that is, when the working mode is the battery mode, check whether the insulation fault detection process is completed. If it is completed, the controller of the BMS enters the sleep state. If it is not completed, the controller of the BMS maintains the fault detection state. Continue to complete the detection of insulation faults.

Hereinafter, a specific embodiment will be used to specifically introduce the multiple working modes of the electric vehicle.

As shown in Figure 4, for an electric vehicle, when the car key is inserted but the IG-On (auto ignition gear) is not activated, the controller of the BMS is activated, but the vehicle is not ignited, and the electric vehicle is in battery mode at this time; If the electric vehicle is ignited in battery mode, that is, high-voltage power is applied to the vehicle, it will enter the vehicle mode. If the electric vehicle is not ignited in battery mode, power off the vehicle and enter the battery mode again; if it is in battery mode Insert the charging gun, the electric car starts charging, and enters the fast charging mode. If the charging gun is inserted in the battery mode, the electric car does not start charging, and the charging gun is unplugged, it will enter the battery mode again; among them, entering the vehicle mode and working mode are: Triggered by the user's operation, such as ignition operation or plug-in charging gun operation, etc. After the whole vehicle is powered off (the user turns off the engine or stops charging), the user no longer needs to use the car, and because the insulation detection cycle is long, the BMS can delay entering the sleep mode at this time, and after the battery insulation resistance detection is completed, Go to sleep again.

An embodiment of the present application also provides an electric vehicle insulation fault detection device, which is configured to execute the electric vehicle insulation fault detection method provided by the above embodiments of the present application. introduce.

FIG. 5 is a structural diagram of an electric vehicle insulation fault detection device according to an embodiment of the present application. As shown in FIG. 5 , the electric vehicle insulation fault detection device includes: a determination module 51 , a collection module 52 , a first determination module 53 , a second determination module 54 and a processing module 55 .

The determination module 51 is configured to obtain the current working mode of the electric vehicle, and determine the system to be detected that needs to detect the insulation fault based on the working mode.

The collection module 52 is configured to collect the insulation resistance value of the system to be tested after the system to be tested is determined.

The first judgment module 53 is configured to compare the insulation resistance value with a preset threshold value corresponding to the current working mode of the electric vehicle, to judge whether an insulation fault occurs, and to obtain a first judgment result.

The second judgment module 54 is configured to further judge whether the insulation fault is a serious fault or a minor fault if the first judgment result is that an insulation fault occurs, and obtain a second judgment result.

The processing module 55 is configured to select corresponding fault handling measures for processing based on the second judgment result.

In one embodiment, the determining module 51 is configured to obtain the main relay status, the charging relay status and the charging gun connection status after the controller of the battery management system of the electric vehicle is started; if the main relay is disconnected, the charging relay is disconnected and the charging If the gun is not connected, the electric vehicle is currently in battery mode; if the main relay is closed, the charging relay is disconnected, and the charging gun is not connected, the electric vehicle is currently in vehicle mode; the main relay is closed, the charging relay is closed, and the charging gun is connected, then the electric vehicle The car is currently in fast charge mode.

In one embodiment, the determining module 51 is further configured to determine that the system to be detected is a power battery if the current mode of the electric vehicle is the battery mode; if the current mode of the electric vehicle is the vehicle mode, then determine that the system to be detected is the vehicle. High-voltage system; if the current mode of the electric vehicle is the fast-charging mode, it is determined that the system to be detected is the vehicle high-voltage system and the charging pile system.

In one embodiment, when the working mode is the battery mode, the first judgment module 53 is set to compare the insulation resistance value with the first preset threshold value, and if the insulation resistance value is less than the first preset threshold value, the first judgment result is for insulation failure.

The second judgment module 54 is configured to compare the insulation resistance value with the second preset threshold value, and if the insulation resistance value is smaller than the second preset threshold value, the second judgment result is that the insulation fault is the second fault level, wherein the second preset threshold value is the second judgment result. The threshold is set to be less than the first preset threshold; if the insulation resistance value is greater than the second preset threshold and less than the first preset threshold, the second judgment result is that the insulation fault is the first fault level.

In one embodiment, when the working mode is the vehicle mode, the first judgment module 53 is configured to compare the insulation resistance value with the third preset threshold value, and if the insulation resistance value is less than the third preset threshold value, the first judgment The result is an insulation failure.

The second judgment module 54 is configured to compare the insulation resistance value with the fourth preset threshold value, and if the insulation resistance value is less than the fourth preset threshold value, the second judgment result is that the insulation fault is the second fault level, wherein the fourth preset threshold value is the second judgment result. The threshold is set to be less than the third preset threshold; if the insulation resistance value is greater than the fourth preset threshold and less than the third preset threshold, the second judgment result is that the insulation fault is the first fault level.

In one embodiment, when the working mode is the fast charging mode, the first judgment module 53 is configured to compare the insulation resistance value with the fifth preset threshold value, and if the insulation resistance value is less than the fifth preset threshold value, the first judgment The result is an insulation failure.

The second judgment module 54 is configured to compare the insulation resistance value with the sixth preset threshold value, if the insulation resistance value is less than the sixth preset threshold value, the second judgment result is that the insulation fault is the second fault level; if the insulation resistance value is greater than the sixth preset threshold value If the sixth preset threshold is smaller than the fifth preset threshold, the second judgment result is the first failure level.

In one embodiment, the processing module 55 is configured to select at least one of the following fault handling measures for processing if the second judgment result is that the insulation fault is the second fault level: prohibiting charging, prohibiting power-on or meter prompts; The second judgment result is that the insulation fault is the first fault level, and at least one of the following fault handling measures is selected for processing: display power or meter prompts.

In one embodiment, the electric vehicle insulation fault detection device further includes: a first fault level processing module, and a second fault level processing module.

The second fault level processing module is set to store the fault flag of the insulation fault when the second judgment result is that the insulation fault is a serious fault; when the system to be detected is powered on again, the insulation fault is reported to the vehicle controller, and the fault snapshot is displayed in the fault snapshot. The operating mode when the storage failure occurs.

The first fault level processing module is set to store the fault code of the insulation fault if the second judgment result is that the insulation fault is a minor fault; store the working mode at the time of the fault in the fault snapshot, and reset it when the system to be detected is powered on again. Check for insulation faults.

The implementation principle and technical effect of the device provided by an embodiment of the present application are the same as those of the foregoing method embodiment. For brief description, for the parts not mentioned in the system embodiment, reference may be made to the corresponding content in the foregoing method embodiment.

The electric vehicle insulation fault detection method provided by an embodiment of the present application has the same technical features as the electric vehicle insulation fault detection device provided by the above-mentioned embodiment, so it can also solve the same technical problem and achieve the same technical effect.

An embodiment of the present application further provides an electric vehicle, which includes a battery management system that executes the method for detecting an insulation fault of an electric vehicle described in any of the foregoing embodiments.

The electric vehicle provided by an embodiment of the present application includes a battery management system that executes the method for detecting an insulation fault of an electric vehicle in the above-mentioned embodiment. Therefore, the electric vehicle provided by the embodiment of the present application also has the beneficial effects described in the above-mentioned embodiment. No longer.

Claims

A method for detecting insulation faults of electric vehicles, comprising:

Obtain the current working mode of the electric vehicle, and determine the system to be detected that needs to detect insulation faults based on the working mode;

collecting the insulation resistance value of the system to be detected;

Comparing the insulation resistance value with a preset threshold value corresponding to the current working mode of the electric vehicle, judging whether an insulation fault has occurred, and obtaining a first judgment result;

In the case that the first judgment result is that an insulation fault has occurred, judge that the insulation fault is a first fault level or a second fault level, and obtain a second judgment result; and

Corresponding fault handling measures are selected for processing based on the second judgment result.
The method according to claim 1, wherein the obtaining the current working mode of the electric vehicle comprises:

After the controller of the battery management system of the electric vehicle is started, the main relay status, the charging relay status and the charging gun connection status are obtained;

When the main relay is disconnected, the charging relay is disconnected, and the charging gun is not connected, the current working mode of the electric vehicle is the battery mode;

When the main relay is closed, the charging relay is open, and the charging gun is not connected, the current operating mode of the electric vehicle is the vehicle mode; and

When the main relay is closed, the charging relay is closed, and the charging gun is connected, the current working mode of the electric vehicle is a fast charging mode.
The method according to claim 2, wherein the determining, based on the operating mode, the system to be detected that needs to be detected for insulation faults comprises:

When the current operating mode of the electric vehicle is the battery mode, the system to be detected is a power battery;

When the current operating mode of the electric vehicle is the vehicle mode, the system to be detected is a vehicle high-voltage system; and

In the case that the current working mode of the electric vehicle is the fast charging mode, the system to be detected is a high-voltage system of the whole vehicle and a charging pile system.
The method according to claim 2, wherein when the current mode of the electric vehicle is a battery mode, the comparing the insulation resistance value with a preset threshold corresponding to the current working mode of the electric vehicle, Determining whether an insulation fault has occurred, and obtaining a first judgment result includes: comparing the insulation resistance value with a first preset threshold, and in the case that the insulation resistance value is less than the first preset threshold, the first judgment The result is an insulation failure;

In the case where the first judgment result is that an insulation fault occurs, judging that the insulation fault is the first fault level or the second fault level, and obtaining the second judgment result includes:

The insulation resistance value is compared with a second preset threshold value, and in the case that the insulation resistance value is less than the second preset threshold value, the second judgment result is the second failure level, wherein the first 2. The preset threshold is less than the first preset threshold;

When the insulation resistance value is greater than the second preset threshold value and less than the first preset threshold value, the second judgment result is the first failure level.
The method according to claim 2, wherein, when the current working mode of the electric vehicle is a vehicle mode, performing the step of comparing the insulation resistance value with a preset threshold value corresponding to the current working mode of the electric vehicle Compare and judge whether an insulation fault has occurred, and obtain the first judgment result including:

The insulation resistance value is compared with a third preset threshold value, and when the insulation resistance value is less than the third preset threshold value, the first judgment result is that an insulation fault occurs;

When the first judgment result is that an insulation fault occurs, judging that the insulation fault is the first fault level or the second fault level, and obtaining the second judgment result includes:

Comparing the insulation resistance value with a fourth preset threshold value, in the case that the insulation resistance value is less than the fourth preset threshold value, the second judgment result is the second failure level, wherein the first Four preset thresholds are smaller than the third preset threshold;

When the insulation resistance value is greater than the fourth preset threshold value and less than the third preset threshold value, the second judgment result is the first failure level.
The method according to claim 2, wherein when the current working mode of the electric vehicle is a fast charging mode, the preset value corresponding to the current working mode of the electric vehicle The thresholds are compared to determine whether an insulation fault has occurred, and the first judgment result obtained includes:

The insulation resistance value is compared with a fifth preset threshold value, and when the insulation resistance value is less than the fifth preset threshold value, the first judgment result is that an insulation fault occurs;

When the first judgment result is that an insulation fault occurs, judging that the insulation fault is the first fault level or the second fault level, and obtaining the second judgment result includes:

comparing the insulation resistance value with a sixth preset threshold value, and in the case that the insulation resistance value is less than the sixth preset threshold value, the second judgment result is the second failure level;

When the insulation resistance value is greater than the sixth preset threshold value and less than the fifth preset threshold value, the second judgment result is the first failure level.
The method according to claim 2, wherein, when the current operating mode of the electric vehicle is the battery mode or the vehicle mode, the selecting corresponding fault handling measures based on the second judgment result for processing comprises:

In the case that the second judgment result is the second fault level, at least one of the following fault handling measures is selected: charging prohibition, power-on prohibition or meter prompt;

If the second judgment result is that the insulation fault is of the first fault level, select at least one of the following fault handling measures: display power or meter prompt;

When the current mode of the electric vehicle is the fast charging mode, selecting the corresponding fault handling measures based on the second judgment result for processing includes:

In the case that the second judgment result is that the insulation fault is a second fault level, the charging is terminated, but the fault code is not latched and the insulation resistance value is not saved; and

In the case that the second judgment result is that the insulation fault is the first fault level, a prompt message "This charging pile insulation is abnormal, please use it with care" is returned to the user.
The method according to claim 2, wherein, when the current mode of the electric vehicle is the battery mode or the vehicle mode, and in the case that the second judgment result is the second failure level, the method further comprises:

storing a fault flag for said insulation fault; and

When the system to be detected is powered on again, the insulation fault is reported to the vehicle controller, and the working mode when the fault occurs is stored in the fault snapshot;

When the second judgment result is that the insulation fault is of the first fault level, the method further includes:

storing a fault code for said insulation fault; and

The working mode when the fault occurs is stored in the fault snapshot, and whether the insulation fault exists is re-detected when the system to be detected is powered on again.
The method according to claim 1, wherein, when the current operating mode of the electric vehicle is the battery mode, after selecting the corresponding fault handling measures based on the second judgment result for processing, the method further comprises: : Whether the insulation fault detection process is completed, if the insulation fault detection process is completed, it will enter the sleep state, and if the insulation fault detection process is not completed, the fault detection state will be maintained.
An electric vehicle insulation fault detection device, comprising:

A determination module, configured to obtain the current working mode of the electric vehicle, and determine a system to be detected that needs to detect an insulation fault based on the working mode;

a collection module, configured to collect the insulation resistance value of the system to be detected;

a first judgment module, configured to compare the insulation resistance value with a preset threshold value corresponding to the current working mode of the electric vehicle, to judge whether an insulation fault has occurred, and to obtain a first judgment result;

a second judgment module, configured to judge that the insulation fault is a first fault level or a second fault level when the first judgment result is an insulation fault, and obtain a second judgment result; and

The processing module is configured to select corresponding fault handling measures for processing based on the second judgment result.