Electric vehicle troubleshooting system and method

Abstract

The invention discloses an electric vehicle troubleshooting system and method. The system comprises a pre-charging detection module and a pre-charging detection loop module which are connected to an electric vehicle bus in parallel. The pre-charging detection loop module comprises a plurality of pre-charging detection branch circuits which are connected in parallel, each pre-charging detection branch circuit is connected with an electric vehicle bus, and each pre-charging detection branch circuit comprises a high-voltage component and a high-voltage relay used for controlling the on-off of the current pre-charging detection branch circuit; the detection end of the pre-charging detection module is connected with an electric vehicle bus, the power supply end of the pre-charging detection module is connected with an electric vehicle battery system, and the pre-charging detection module is used for carrying out pre-charging troubleshooting on a high-voltage part corresponding to the high-voltage relay according to the resistance value and / or tube voltage drop value of the electric vehicle bus. According to the electric vehicle troubleshooting system and method provided by the embodiment of the invention, automatic insulation and pre-charging troubleshooting are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle fault detection, and in particular to an electric vehicle fault troubleshooting system and method. Background Art

[0002] As electric vehicles become more and more widely used, existing electric vehicle pre-charging failures are becoming more and more common.

[0003] In the prior art, the troubleshooting method for electric vehicles is a manual method. For example, for insulation faults, the insulation resistance of the electric vehicle bus is measured by using an automatic fault detection function or an external insulation meter. For pre-charge faults, the tube voltage drop of the electric vehicle bus is measured by using a multimeter diode. If there is an abnormality, the high-voltage component connectors are manually unplugged and plugged in to troubleshoot one by one.

[0004] It can be seen that how to realize automatic fault detection has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The present invention provides an electric vehicle fault troubleshooting system and method to solve the technical problem of how to realize automatic troubleshooting of electric vehicle faults, so as to achieve the effect of automatic fault detection.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides an electric vehicle fault troubleshooting system, including a pre-charge detection module and a pre-charge detection loop module connected in parallel to the electric vehicle bus;

[0007] The pre-charge detection circuit module includes a plurality of pre-charge detection branches connected in parallel, each of which is connected to the electric vehicle bus, and each of which includes a high-voltage component and a high-voltage relay for controlling the on and off of the current pre-charge detection branch;

[0008] The detection end of the pre-charge detection module is connected to the electric vehicle bus, and the power supply end of the pre-charge detection module is connected to the electric vehicle battery system. The pre-charge detection module is used to perform pre-charge fault troubleshooting on the high-voltage component corresponding to the high-voltage relay according to the resistance value and / or tube voltage drop value of the electric vehicle bus.

[0009] As one of the preferred solutions, the electric vehicle fault troubleshooting system further includes a secondary insulation detection module, a main positive relay and a main negative relay;

[0010] The detection end of the secondary insulation detection module is connected to the positive pole of the electric vehicle bus through the main positive relay, and the detection end of the secondary insulation detection module is also connected to the negative pole of the electric vehicle bus through the main negative relay. The power supply end of the secondary insulation detection module is connected to the external electric vehicle battery system, and the secondary insulation detection module is used to control the selected high-voltage relay to realize insulation fault detection of the high-voltage component.

[0011] An embodiment of the present invention provides an electric vehicle fault troubleshooting method, which is applied to any of the electric vehicle fault troubleshooting systems described above. The electric vehicle fault troubleshooting method includes:

[0012] When a pre-charge fault code is detected, the pre-charge fault troubleshooting mode is entered;

[0013] According to the detected power battery voltage value and insulation resistance value of the electric vehicle battery system, determine whether there is a power battery internal pre-charging fault;

[0014] When the fault does not belong to the internal pre-charging fault of the power battery, it is determined whether a high-voltage component pre-charging fault occurs according to the resistance value and / or tube voltage drop value of the electric vehicle busbar.

[0015] As one of the preferred solutions, after disconnecting all the high-voltage relays, if an insulation fault code is read, an abnormal voltage in the power battery is detected, or an abnormal insulation resistance is detected, it is determined that an internal pre-charging fault of the power battery occurs.

[0016] As one of the preferred solutions, when the insulation fault code is not read, the voltage abnormality in the power battery is not detected, or the insulation resistance abnormality is not detected, the pre-charge detection module is started;

[0017] After starting the pre-charge detection module, closing each of the high-voltage relays in sequence, and reading the feedback results of the pre-charge detection module after each closure, until the pre-charge detection module detects that the resistance value and / or the tube voltage drop value of the electric vehicle busbar are abnormal;

[0018] When it is detected that the resistance value and / or the tube voltage drop value of the electric vehicle busbar is abnormal, it is determined that the high-voltage component pre-charging fault occurs in the corresponding high-voltage component.

[0019] As one of the preferred solutions, before disconnecting all the high-voltage relays, the electric vehicle fault troubleshooting method further includes:

[0020] Under the condition of high-voltage power-on control of the whole vehicle, reading the pre-charge fault code;

[0021] Under the condition of high-voltage power control of the whole vehicle, after clearing the pre-charge fault code, all the high-voltage relays are disconnected.

[0022] As one of the preferred solutions, the abnormal situation of the resistance value of the electric vehicle busbar includes any one of the following: the positive / negative resistance value is different from the negative / positive resistance value, the ratio of the positive / negative resistance value to the negative / positive resistance value or the ratio of the negative / positive resistance value to the positive / negative resistance value is greater than a first threshold value, and the positive / negative resistance value and the negative / positive resistance value are greater than a second threshold value;

[0023] The abnormal conditions of the tube pressure drop value include any one of the following: the positive / negative tube pressure drop value is different from the negative / positive tube pressure drop value, the positive / negative tube pressure drop value is less than the third threshold and the negative / positive tube pressure drop value cannot be detected, and the positive / negative tube pressure drop value cannot be detected and the negative / positive tube pressure drop value is less than the third threshold.

[0024] As one of the preferred solutions, the electric vehicle fault troubleshooting method further includes:

[0025] After detecting that the insulation resistance is less than the first preset value and reading the insulation fault code, determining that the first insulation fault troubleshooting mode is satisfied, and determining whether a power battery insulation fault or a high-voltage component insulation fault occurs according to the action feedback information of the insulation fault code read; and,

[0026] After detecting that the insulation resistance is less than the second preset value and the insulation fault code is not read, it is determined that the second insulation fault troubleshooting mode is satisfied, and based on the action feedback information of the insulation resistance read, it is determined whether a power battery insulation fault or a high-voltage component insulation fault occurs.

[0027] As one of the preferred solutions, the determining that the first insulation fault troubleshooting mode is satisfied and determining whether a power battery insulation fault or a high-voltage component insulation fault occurs according to the action feedback information of the insulation fault code read include:

[0028] When the first insulation fault troubleshooting mode is satisfied, if the insulation fault code is detected to reappear after the insulation fault code is cleared, it is determined that the type of the insulation fault is the power battery insulation fault; and,

[0029] When the first insulation fault troubleshooting mode is met, if the insulation fault code is not detected to reappear after clearing the insulation fault code, the insulation fault code reappearance action is executed, and each of the high-voltage relays is disconnected in turn until the insulation fault code is not detected to reappear and / or the insulation resistance is detected to meet the first preset, and it is determined that the current corresponding high-voltage component has the high-voltage component insulation fault, wherein the insulation fault code reappearance action includes shielding the vehicle controller, and controlling the main positive relay and the main negative relay in the electric vehicle fault troubleshooting system to close.

[0030] As one of the preferred solutions, the determining whether the second insulation fault troubleshooting mode is satisfied and determining whether a power battery insulation fault or a high-voltage component insulation fault occurs according to the action feedback information of the insulation resistance value read includes:

[0031] When the second insulation fault troubleshooting mode is satisfied, if the insulation resistance is detected to reappear after the insulation resistance is cleared, it is determined that the type of the insulation fault is the power battery insulation fault; and,

[0032] When the second insulation fault troubleshooting mode is met, if the insulation resistance is not detected to reappear after clearing the insulation resistance, the insulation resistance reappearance action is executed, and each of the high-voltage relays is closed in turn until the detected insulation resistance meets the second preset, and it is determined that the current corresponding high-voltage component has the high-voltage component insulation fault, wherein the insulation resistance reappearance action includes operating the secondary insulation detection module in the electric vehicle fault troubleshooting system.

[0033] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0034] (1) The fault troubleshooting system of the present invention and the troubleshooting method based on the electric vehicle fault troubleshooting system do not require manual measurement of the parameters of each component and manual analysis, which greatly reduces the manpower and time costs of troubleshooting and realizes automated insulation and pre-charging fault troubleshooting;

[0035] (2) When a vehicle breaks down, the sampling frequency of manual detection data is low. In many cases, it is even impossible to collect data on occasional faults, resulting in troubleshooting failure. This circuit and method can continuously and uninterruptedly collect parameter data on components with a high sampling frequency and a long cycle, which is particularly effective for troubleshooting and analysis of occasional faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the structure of an electric vehicle fault troubleshooting system in one embodiment of the present invention;

[0037] Figure 2 It is a flow chart of a method for troubleshooting electric vehicle pre-charging faults in one embodiment of the present invention;

[0038] Figure 3 It is a structural schematic diagram of an electric vehicle pre-charging and insulation fault troubleshooting system in one embodiment of the present invention;

[0039] Figure 4 It is a flow chart of a pre-charging fault troubleshooting method based on an electric vehicle pre-charging and insulation fault troubleshooting system in one embodiment of the present invention;

[0040] Figure 5 It is a flow chart of a method for troubleshooting an insulation fault in an electric vehicle based on an electric vehicle pre-charging and insulation fault troubleshooting system in one embodiment of the present invention, in which the insulation resistance of the electric vehicle is less than a preset threshold and an insulation fault is reported;

[0041] Figure 6 It is a flow chart of a method for troubleshooting an electric vehicle in which the insulation resistance of the electric vehicle is less than a preset threshold and no insulation fault is reported based on the electric vehicle pre-charging and insulation fault troubleshooting system in one embodiment of the present invention.

[0042] Reference numerals:

[0043] Among them, 1. Electric vehicle fault troubleshooting system; 2. Pre-charge detection circuit module; 21. Pre-charge detection branch; 211. High-voltage relay; 212. High-voltage components; 3. Pre-charge detection module; 4. Insulation and pre-charge detection unit; 5. Battery management system; 6. Secondary insulation detection module; 7. Main positive relay; 8. Main negative relay; 9. Electric vehicle bus. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the description of this application, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0046] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are only for illustrative purposes, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0047] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0048] When an electric vehicle is charging, a pre-charging circuit is usually set up to prevent excessive current from having an adverse effect on the relay. The main function of the pre-charging circuit is to charge the pre-charging capacitor of the motor controller, thereby reducing the spark arcing phenomenon generated when the high-voltage relay 211 is closed, thereby preventing high-voltage shock from causing damage to components and improving the safety performance of the entire high-voltage system.

[0049] In the pre-charging mechanism of electric vehicles, if an abnormality occurs in the pre-charging process, such as the charging time is too long and the expected voltage is not reached, it is regarded as a pre-charging failure. The pre-charging failure may cause the high-voltage system to fail to work normally, thereby affecting the charging and driving performance of new energy vehicles. If the pre-charging failure is not repaired in time, it may also cause damage to other components of the high-voltage system, increasing maintenance costs.

[0050] The pre-charging fault code is a specific code recorded and generated by the battery system or related battery management system of an electric vehicle when a problem occurs during the pre-charging stage of an electric vehicle or a new energy vehicle. These codes are used to indicate the specific type of fault that occurs during the pre-charging process so that maintenance personnel can quickly locate and solve the problem.

[0051] At the same time, insulation failure is also a possible fault in the electrical system of electric vehicles, posing a threat to the safety and reliability of electric vehicles. Insulation failure refers to the phenomenon of short circuit, leakage, etc. caused by damage to insulating materials in electrical equipment or circuits. In electric vehicles, insulation failure may cause damage to high-voltage components such as batteries and motors, and may even cause serious accidents such as fire.

[0052] The insulation fault code is the fault information recorded by the battery system of an electric vehicle or the related battery management system when it detects abnormal insulation resistance. At the same time, insulation faults will also cause the insulation resistance value of electrical equipment or lines to deviate from the normal range. Under normal circumstances, the insulation resistance should be high enough to prevent current from leaking into the surrounding environment or other parts that should not conduct electricity.

[0053] There are two types of abnormal insulation resistance. One is lower than the standard value. Different electric vehicle electrical equipment and lines have corresponding insulation resistance qualification standards according to their voltage level, use environment and other factors. When the measured insulation resistance value is lower than the specified standard value, it is considered abnormal insulation resistance. The other is unstable change. When the insulation resistance of electrical equipment or lines is regularly tested, if a large fluctuation in the insulation resistance value is found, it is also an abnormal situation.

[0054] When the insulation is severely damaged and the insulation resistance is almost zero, the current will bypass the normal conductive path and flow directly between conductors with different potentials, causing a short circuit. The short circuit will generate a large current, which may cause serious consequences such as damaging the electrical equipment of the electric vehicle and causing a fire.

[0055] In order to troubleshoot pre-charging faults and insulation faults, an embodiment of the present invention provides an electric vehicle fault troubleshooting system. For details, see Figure 1 , Figure 1 An electric vehicle fault troubleshooting system in one embodiment of the present invention is shown.

[0056] The electric vehicle fault troubleshooting system 1 comprises a pre-charge detection module 3 and a pre-charge detection loop module 2 connected in parallel to the electric vehicle bus.

[0057] The pre-charge detection circuit module 2 includes a plurality of pre-charge detection branches connected in parallel, each of which is connected to the electric vehicle bus, and each of which includes a high-voltage component 212 and a high-voltage relay 211 for controlling the current high-voltage component 212 .

[0058] The pre-charge detection module 3 includes a resistance detection circuit and / or a tube voltage drop detection circuit, the detection end of the resistance detection circuit and / or the tube voltage drop detection circuit is connected to the electric vehicle bus, the power supply end of the resistance detection circuit and / or the tube voltage drop detection circuit is connected to the external electric vehicle battery system, and the pre-charge detection module 3 is used to control the selected high-voltage relay 211 to realize pre-charge fault troubleshooting of the high-voltage component 212.

[0059] Among them, the resistance detection circuit includes the volt-ampere method detection circuit, the Wheatstone bridge method detection circuit and the substitution method detection circuit, etc. The tube voltage drop detection circuit includes the IGBT tube voltage drop detection circuit, the diode tube voltage drop detection circuit and the self-driven power semiconductor conduction voltage drop detection circuit, etc. Different detection circuits have different working principles, which will not be elaborated here one by one.

[0060] Specifically, the pre-charge detection module 3 is used to monitor the pre-charge voltage and current in real time, and to perform pre-charge fault troubleshooting on the power battery of the electric vehicle and the high-voltage component 212 corresponding to the high-voltage relay 211. The pre-charge detection module 3 is powered by the low-voltage battery of the electric vehicle or the external electric vehicle battery system. The resistance detection circuit detects the positive / negative resistance value and negative / positive resistance value of the bus, and the tube voltage drop detection circuit detects the positive / negative tube voltage drop value and negative / positive tube voltage drop value of the bus, thereby realizing the troubleshooting of pre-charge faults.

[0061] Among them, the electric vehicle busbar is the core conductive component in the electric vehicle system, which is mainly responsible for transmitting electrical energy, connecting battery packs, motor controllers and various high-voltage components 212. The busbar transmits electrical energy by conducting direct current internally to ensure the normal operation of the electric vehicle.

[0062] In a specific embodiment, the electric vehicle fault troubleshooting system 1 also includes a secondary insulation detection module, a main positive relay and a main negative relay, wherein the detection end of the secondary insulation detection module is connected to the positive pole of the electric vehicle bus through the main positive relay, and the detection end of the secondary insulation detection module is also connected to the negative pole of the electric vehicle bus through the main negative relay. The power supply end of the secondary insulation detection module is connected to the external electric vehicle battery system, and the secondary insulation detection module is used to control the selected high-voltage relay 211 to realize insulation fault troubleshooting of the high-voltage component 212.

[0063] Specifically, the secondary insulation detection module can monitor the insulation resistance value of the power equipment in real time and predict the occurrence trend of insulation failures through data analysis. Once the insulation resistance is detected to be too low, the module will issue an alarm message to remind the user or vehicle control system to perform maintenance.

[0064] During operation, the main positive relay and the main negative relay ensure the safe, stable and efficient operation of the battery pack by controlling the connection and disconnection of the positive and negative circuits of the battery pack.

[0065] In this embodiment, the secondary insulation detection module includes a boost chopper circuit, and a voltage output end of the boost chopper circuit is connected to the busbar of the electric vehicle.

[0066] In the electrical system of a car, the positive pole of the bus is usually connected to the positive pole of the power source or the positive pole of the battery, and the electrical energy is transmitted to each high-voltage component 212 through the bus. The negative pole of the bus is usually connected to the negative pole of the power source or the negative pole of the battery, and the electrical energy is transmitted to each high-voltage component 212 through the bus.

[0067] In a specific embodiment, the high-voltage electrical architecture of the electric vehicle also includes a pre-charging detection circuit module 2, which includes a plurality of parallel pre-charging detection branches, each of which is connected to the electric vehicle bus, and each of which includes a high-voltage component 212 and a high-voltage relay 211 for controlling the current high-voltage component 212. A high-voltage relay 211 is designed at the high-voltage end of each high-voltage component 212, and each pre-charging detection branch is connected in parallel and connected to the pre-charging detection module 3.

[0068] Specifically, the high-voltage components 212 mainly include a drive motor, a high-voltage distribution box, an electric compressor, an on-board charger, and a motor controller, etc. These are only illustrative examples, and the specific high-voltage components 212 shall be subject to the specific electric vehicle.

[0069] In an electric vehicle, each high-voltage component 212 corresponds to a high-voltage relay 211. As a controlled switch device, the high-voltage relay 211 can accurately control the on and off of each high-voltage component 212. When a certain high-voltage component 212 is required to work, the corresponding high-voltage relay 211 is closed to allow current to flow; when the component is not required to work, the relay is disconnected to cut off the current. At the same time, the high-voltage relay 211 can also be used as an entry point for troubleshooting.

[0070] The electric vehicle fault troubleshooting system 1 can perform pre-charging fault troubleshooting, troubleshooting of electric vehicle insulation resistance less than a preset threshold and insulation fault reporting, and troubleshooting of insulation resistance less than a preset threshold and no insulation fault reporting.

[0071] An embodiment of the present invention provides a method for troubleshooting electric vehicle pre-charging faults. For details, see Figure 2 , Figure 2 Shown is a flow chart of a pre-charge fault troubleshooting method in one embodiment of the present invention.

[0072] In this embodiment, the pre-charge fault troubleshooting judgment condition is:

[0073] When a pre-charge fault code is detected, the pre-charge fault troubleshooting mode is entered;

[0074] According to the detected power battery voltage value and insulation resistance value of the electric vehicle battery system, determine whether there is a power battery internal pre-charging fault;

[0075] When it is not a pre-charging fault inside the power battery, determine whether a pre-charging fault of the high-voltage component occurs based on the resistance value and / or tube voltage drop value of the electric vehicle busbar.

[0076] Based on the pre-charge fault troubleshooting judgment conditions, the specific process of the pre-charge fault troubleshooting method is as follows:

[0077] S1: After disconnecting all high-voltage relays 211, if an insulation fault code is read, an abnormal voltage in the power battery is detected, or an abnormal insulation resistance is detected, it is determined that a power battery internal pre-charging fault occurs;

[0078] S2: When no insulation fault code is read, no abnormal voltage in the power battery is detected, or no abnormal insulation resistance is detected, the pre-charge detection module is started;

[0079] S3: After starting the pre-charge detection module, close each high-voltage relay 211 in sequence, and read the feedback results of the pre-charge detection module after each closure, until the pre-charge detection module detects that the resistance value and / or the tube voltage drop value of the electric vehicle bus are abnormal;

[0080] S4: When it is detected that the resistance value and / or the tube voltage drop value of the electric vehicle busbar is abnormal, it is determined that a high-voltage component pre-charging fault occurs in the current corresponding high-voltage component 212 .

[0081] Before controlling the insulation and pre-charge fault detection unit to disconnect all high-voltage relays 211, the following steps need to be performed:

[0082] Under the condition that the whole vehicle is powered on with high voltage, the pre-charge fault code is read; under the condition that the whole vehicle is powered off with high voltage, after the pre-charge fault code is cleared, the step of disconnecting all high-voltage relays 211 is executed.

[0083] The vehicle's high-voltage power-on control is a key step in starting new energy vehicles. According to the driver's control of the driving key switch, the vehicle controller receives the start signal and controls the high-voltage circuit of the power battery by controlling the high-voltage contactor switch.

[0084] Vehicle high-voltage power-down control is a necessary step when shutting down new energy vehicles to ensure the safe parking of the vehicle. The vehicle controller (VCU) sends instructions to each controller to stop working and disconnect the high-voltage circuit based on the driver's shutdown signal or emergency situation.

[0085] Specifically, the pre-charging fault troubleshooting method implemented on the basis of the electric vehicle fault troubleshooting system 1 includes the following steps:

[0086] Step 1: Under the condition of high-voltage power-on control of the vehicle, the normal operation is to turn the key to the On position + step on the foot brake pedal to read the pre-charge fault code. If there is one, then go to step 2 under the condition of high-voltage power-off control of the vehicle;

[0087] Step 2: Clear the vehicle pre-charge fault code, disconnect all high-voltage components 212 relays after a period of time; read the voltage, insulation resistance and fault code in the power battery under the high-voltage power-on control condition of the vehicle; if the voltage or insulation resistance in the power battery is abnormal or an insulation fault code appears, it is determined to be a pre-charge fault inside the power battery; if the above abnormality does not occur, go to step 3;

[0088] Step 3: Start the pre-charge detection module 3 to determine the bus resistance value and / or the tube voltage drop value;

[0089] Step 4: Close the high-voltage relay 211 in sequence, and read the feedback result of the pre-charging detection module 3 after each closing of the high-voltage relay 211, until the pre-charging detection module 3 detects that the resistance value and / or the tube voltage drop value of the bus are abnormal, and based on the resistance value and / or the tube voltage drop value of the electric vehicle bus, output the fault type of the electric vehicle as the pre-charging fault of the high-voltage component of the electric vehicle connected to the high-voltage relay 211 when the resistance value and / or the tube voltage drop value of the bus is abnormal.

[0090] In this embodiment, the resistance value refers to the resistance generated by the electric vehicle busbar when transmitting current, and the pipe voltage drop value refers to the voltage drop caused by the existence of resistance when current passes through a pipe or a wire.

[0091] The abnormal conditions of the resistance value of the electric vehicle busbar include that the positive / negative resistance value is different from the negative / positive resistance value, the ratio of the positive / negative resistance value to the negative / positive resistance value or the ratio of the negative / positive resistance value to the positive / negative resistance value is greater than a first threshold, and the positive / negative resistance value and the negative / positive resistance value are greater than a second threshold;

[0092] Under normal circumstances, the resistance value of the electric vehicle busbar should be stable and will not change due to changes in the direction of the current. If the positive / negative resistance value is different from the negative / positive resistance value, this may mean that the busbar has asymmetric resistance characteristics, which may be caused by factors such as uneven busbar material, poor connection, or interference from the external environment.

[0093] When the ratio of the positive / negative resistance value to the negative / positive resistance value or the ratio of the negative / positive resistance value to the positive / negative resistance value is greater than a first threshold value, usually, the first threshold value is greater than 1000; this abnormal ratio indicates that the change in the bus resistance value exceeds the normal range. The first threshold value is a preset critical value used to determine whether the change in resistance value is significant. If the ratio is greater than the first threshold value, it means that the electric vehicle bus or high-voltage component 212 has a fault, resulting in a resistance problem, such as a sharp increase in resistance, unstable resistance, etc.

[0094] When the positive / negative resistance value and the negative / positive resistance value are greater than the second threshold, the second threshold is greater than 2 megohms. The second threshold is a preset upper limit of the resistance value, which is used to determine whether the bus resistance is within an acceptable range. If the resistance value is greater than the second threshold, it means that the bus resistance of the electric vehicle is too large, thereby increasing the loss during current transmission.

[0095] Abnormal tube voltage drop values ​​include that the positive / negative tube voltage drop value is different from the negative / positive tube voltage drop value, the positive / negative tube voltage drop value is less than the third threshold and the negative / positive tube voltage drop value cannot be detected, and the positive / negative tube voltage drop value cannot be detected and the negative / positive tube voltage drop value is less than the third threshold. Typically, the third threshold is less than 1 volt.

[0096] Specifically, when the current flows from one end of the busbar to the other end (forward current), a voltage drop will be generated due to the existence of the busbar resistance. The value of this voltage drop depends on the magnitude of the current and the resistance of the busbar; if the direction of the current changes (reverse current), theoretically, since the busbar resistance has not changed, the value of the voltage drop should be the same as that of the forward current, that is, the positive / negative tube voltage drop value is the same as the negative / positive tube voltage drop value, but if the positive / negative tube voltage drop value is different from the negative / positive tube voltage drop value, it is determined to be an abnormal voltage drop value, thereby determining whether a pre-charge failure of the high-voltage component occurs.

[0097] Based on the electric vehicle fault troubleshooting system 1, an embodiment of the present invention provides an electric vehicle insulation fault troubleshooting method. In this embodiment, the insulation fault troubleshooting judgment condition is:

[0098] After detecting that the insulation resistance is less than the first preset value and reading the insulation fault code, determining that the first insulation fault troubleshooting mode is satisfied, and determining whether a power battery insulation fault or a high-voltage component insulation fault occurs according to the action feedback information of the insulation fault code read; and,

[0099] After detecting that the insulation resistance is less than the second preset value and the insulation fault code is not read, it is determined that the second insulation fault troubleshooting mode is satisfied, and based on the action feedback information of the insulation resistance read, it is determined whether a power battery insulation fault or a high-voltage component insulation fault occurs.

[0100] In this embodiment, the first insulation fault is that the insulation resistance is less than a preset threshold and an insulation fault is reported, and the second insulation is that the insulation resistance is less than the preset threshold and no insulation fault is reported.

[0101] When the insulation resistance is less than the preset threshold and the insulation fault troubleshooting method is reported, that is, when the first insulation fault troubleshooting mode is met, the action feedback information of the insulation fault code read is used, that is, whether the insulation fault code can be reproduced, to determine whether it is a power battery insulation fault or a high-voltage component insulation fault.

[0102] The specific troubleshooting method when the insulation resistance is less than the preset threshold and insulation fault is reported is as follows:

[0103] Step 1: Under the condition of high-voltage electrical control of the whole vehicle, read the insulation resistance value and the first insulation fault code. After clearing the first insulation fault code, read the second insulation fault code. If the second insulation fault code is the same as the first insulation fault code, it is determined to be a power battery insulation fault.

[0104] Step 2: When the second insulation fault code is not read, shield the vehicle controller in the electric vehicle fault troubleshooting system, and control the main positive relay and the main negative relay in the electric vehicle fault troubleshooting system 1 to close;

[0105] Step 3: Read the insulation fault code and insulation resistance to check whether the vehicle insulation resistance is less than the preset threshold and insulation fault code. If so, proceed to step 4.

[0106] Step 4: Clear the insulation fault code, disconnect the first high voltage relay 211 after a period of time, and check whether the insulation fault code appears after a period of time. If the insulation fault code still appears, proceed to step 5;

[0107] Step 5: Clear the insulation fault code, disconnect the high-voltage relay 211 in sequence, read the insulation fault code and insulation resistance after each disconnection of the high-voltage relay 211, until no insulation fault code appears and / or the insulation resistance is within the preset threshold, and output the fault type of the electric vehicle as the insulation fault of the high-voltage component of the electric vehicle corresponding to the high-voltage relay 211 when the insulation fault code disappears and the insulation resistance is within the preset threshold.

[0108] In step two, if the high-voltage interlock failure fault function of the vehicle controller is not shielded, once the main positive relay and the main negative relay are closed, the vehicle will fail and alarm; in order to check which high-voltage component 212 is faulty, it is necessary to first shield the high-voltage interlock failure fault function of the vehicle controller, and then execute the closing step of the main positive relay and the main negative relay, so that the corresponding high-voltage component 212 fault can be identified by disconnecting the high-voltage relay 211.

[0109] By closing the high-voltage relays 211 in sequence and gradually troubleshooting and locating the insulation fault, maintenance personnel can quickly find and repair the faulty parts, thereby restoring the normal operation of the electric vehicle.

[0110] In the method for troubleshooting an insulation fault when the insulation resistance is less than a preset threshold and no insulation fault is reported, that is, when the second insulation fault troubleshooting mode is met, it is determined whether a power battery insulation fault or a high-voltage component insulation fault occurs based on the action feedback information of the read insulation resistance, that is, whether the insulation resistance can be reproduced.

[0111] The specific troubleshooting methods when the insulation resistance is less than the preset threshold and no insulation fault is reported include:

[0112] Step 1: Under the condition of high voltage electrical control of the whole vehicle, read the first insulation resistance and the insulation fault code to determine whether the first insulation resistance is less than a preset threshold and no insulation fault code appears;

[0113] Step 2: When the first insulation resistance is detected to be less than a preset threshold and no insulation fault code appears, clear the first insulation resistance and read the second insulation resistance. If the second insulation resistance is less than a preset threshold and no insulation fault code appears, determine that there is a power battery insulation fault;

[0114] Step three: if no reappearance of the insulation resistance is detected after clearing the insulation resistance, the insulation resistance reappearance action is performed, and each high-voltage relay 211 is closed in sequence until the detected insulation resistance meets the second preset value, and it is determined that the current corresponding high-voltage component 212 has a high-voltage component insulation fault, wherein the insulation resistance reappearance action includes operating the secondary insulation detection module in the electric vehicle fault troubleshooting system 1.

[0115] In step 1 and step 2, by comparing the insulation resistance values, if the second insulation resistance value is the same as the first insulation resistance value, it indicates that there is a fault of low insulation resistance value in the power battery, and the power battery needs to be repaired.

[0116] Low insulation resistance of power batteries may be caused by a variety of reasons: internal battery structure problems, battery short circuit, installation problems or system vibration, which need to be repaired to ensure the safe and reliable operation of the electric vehicle's high-voltage system.

[0117] In step three, the insulation resistance reproducing action specifically includes starting the secondary insulation detection module, injecting an insulation detection voltage into the busbar through a boost chopper circuit, and reading the insulation resistance.

[0118] When it is suspected that there is a problem with the insulation performance of the high-voltage component 212, the secondary insulation detection module is started. The secondary insulation detection module injects a specific insulation detection voltage into the high-voltage bus outside the power battery through the boost chopper circuit. This voltage is usually higher than the normal operating voltage so as to more accurately detect the performance of the insulation layer. After the insulation detection voltage is injected, the insulation resistance value fed back by the secondary insulation detection module is read. This resistance value reflects the current insulation status of the high-voltage component 212.

[0119] The read insulation resistance is compared with the preset threshold. If the insulation resistance is less than the threshold, it means that there is a problem with the insulation performance of the high-voltage component 212 and further investigation is required. In order to determine the specific component that causes the low insulation resistance, it is necessary to gradually disconnect the high-voltage relay 211 and read the insulation resistance after each disconnection. The purpose of this step is to find out the high-voltage component 212 that causes the low insulation resistance through gradual investigation.

[0120] The insulation resistance is continuously read until the insulation resistance reaches within a preset threshold value, which indicates that the high-voltage component 212 causing the low insulation resistance has been found and the fault has been eliminated by disconnecting the corresponding high-voltage relay 211 .

[0121] Specifically, the high-voltage component 212 causing the insulation fault is determined by judging which high-voltage relay 211 is disconnected and the insulation resistance value returns to normal. According to the output fault type and location, the maintenance personnel can take corresponding measures to repair or replace the faulty component. For example, if it is determined that the insulation layer of a certain high-voltage cable is damaged and causes the fault, then the cable needs to be replaced.

[0122] An embodiment of the present invention provides an electric vehicle fault troubleshooting system. For details, see Figure 3 , Figure 3 The figure shows an electric vehicle pre-charging and insulation fault troubleshooting system in one embodiment of the present invention.

[0123] The electric vehicle pre-charging and insulation fault troubleshooting system comprises an insulation and pre-charging fault detection unit 4 and a battery management system 5 and a plurality of high-voltage relays respectively controlled by the insulation and pre-charging fault detection unit 4;

[0124] The battery management system 5 includes a pre-charge detection module 3, a secondary insulation detection module 6, a main positive relay 7 and a main negative relay 8;

[0125] The detection end of the secondary insulation detection module 6 is connected to the positive pole of the electric vehicle bus 9 through the main positive relay 7, and the detection end of the secondary insulation detection module 6 is also connected to the negative pole of the electric vehicle bus 9 through the main negative relay 8. The power supply end of the secondary insulation detection module 6 is connected to the external electric vehicle battery system, and the secondary insulation detection module 6 is used to control the selected high-voltage relay to realize insulation fault detection of the high-voltage components.

[0126] The insulation and pre-charge fault detection unit 4 (FDU) serves as the hub of insulation and pre-charge fault detection. It communicates and controls with the BMS, pre-charge detection module 3, secondary insulation detection module 6, and high-voltage relays of various high-voltage components and the vehicle controller (VCU) through the vehicle communication network. The communication network is CAN communication or LIN communication, etc.

[0127] The insulation and pre-charge fault detection unit 4 (FDU) has the function of communicating with the vehicle-mounted remote terminal, so as to use the vehicle-mounted remote terminal to exchange data with the automobile after-sales operation and maintenance cloud platform, and remote insulation and pre-charge fault troubleshooting of the automobile can also be realized on the after-sales operation and maintenance cloud platform; at the same time, the insulation and pre-charge fault detection unit 4 (FDU) has the function of clearing the fault codes related to insulation and pre-charge failure of each high-voltage controller and vehicle controller of the electric vehicle.

[0128] The insulation and pre-charge fault detection unit 4 (FDU) has the function of shielding the high-voltage interlock failure fault of the vehicle controller (VCU) or controlling the BMS to open and close the power battery main positive (K positive) relay 7 and main negative (K negative) relay 8 when the vehicle controller (VCU) reports a high-voltage interlock fault.

[0129] The electric vehicle pre-charging and insulation fault troubleshooting system also includes a vehicle controller, which is controlled by the insulation and pre-charging fault detection unit 4 .

[0130] The vehicle control unit (VCU) is the central control unit of new energy vehicles and is the core of the entire control system. The vehicle control unit collects the status of the motor and battery (usually directly interacts with the battery management system 5 signals through CAN communication or LIN communication), and also collects the accelerator pedal signal, brake pedal signal, actuator and sensor signal through its own IO port. After making a corresponding judgment based on the driver's intention, it monitors the actions of the lower-level component controllers. It is responsible for the normal driving of the car, brake energy feedback, energy management of the vehicle drive system and power battery, network management, fault diagnosis and processing, vehicle status monitoring, etc., so as to ensure that the vehicle works normally and stably under good power, high economy and reliability.

[0131] The secondary insulation detection module 6 can monitor the insulation resistance value of the power equipment in real time and predict the occurrence trend of insulation failure through data analysis. Once the insulation resistance value is detected to be too low, the module will issue an alarm message to remind the user or the vehicle control system to perform maintenance.

[0132] During the operation of the battery management system 5 , the main positive relay 7 and the main negative relay 8 ensure the safe, stable and efficient operation of the battery pack by controlling the connection and disconnection of the positive and negative circuits of the battery pack.

[0133] In electric vehicles, each high-voltage component corresponds to a high-voltage relay (K1, K2, .... Kn). As a controlled switch device, the high-voltage relay can accurately control the on and off of each high-voltage component. When a high-voltage component is required to work, the corresponding high-voltage relay is closed to allow current to flow; when the component is not required to work, the relay is disconnected to cut off the current. At the same time, the high-voltage relay can also be used as an entry point for troubleshooting.

[0134] Specifically, the high-voltage components mainly include drive motors, high-voltage distribution boxes, electric compressors, on-board chargers and motor controllers, etc. These are only illustrative examples here, and the specific high-voltage components shall be subject to the specific electric vehicle.

[0135] The electric vehicle pre-charging and insulation fault troubleshooting system can troubleshoot three types of faults: pre-charging fault troubleshooting, troubleshooting when the electric vehicle insulation resistance is less than a preset threshold and insulation fault is reported, and troubleshooting when the insulation resistance is less than a preset value and no insulation fault is reported.

[0136] An embodiment of the present invention provides a method for troubleshooting electric vehicle faults. For details, see Figure 4 , Figure 4 The figure shows a flow chart of a pre-charging fault troubleshooting method based on an electric vehicle pre-charging and insulation fault troubleshooting system in one embodiment of the present invention, the method comprising:

[0137] S11: After controlling the insulation and pre-charge fault detection unit to disconnect all high-voltage relays, controlling the insulation and pre-charge fault detection unit to read the insulation fault code, and determining that it is a power battery internal pre-charge fault when the insulation and pre-charge fault detection unit reads the insulation fault code, detects an abnormal voltage in the power battery, or detects an abnormal insulation resistance;

[0138] S12: When the insulation and pre-charge fault detection unit does not read the insulation fault code, does not detect the abnormal voltage in the power battery, or does not detect the abnormal insulation resistance, the insulation and pre-charge fault detection unit is controlled to start the pre-charge detection module to determine the bus resistance value and / or the tube voltage drop value of the electric vehicle;

[0139] S13: Control the insulation and pre-charge fault detection unit to read the feedback result of the pre-charge detection module after each closing of the high-voltage relay until the pre-charge detection module detects that the resistance value and / or tube voltage drop value of the electric vehicle bus is abnormal, and based on the resistance value and / or tube voltage drop value of the electric vehicle bus, output the fault type of the electric vehicle as the pre-charge fault of the high-voltage component of the electric vehicle corresponding to the high-voltage relay when the resistance value and / or tube voltage drop value of the electric vehicle bus is abnormal.

[0140] Before step S11, it is necessary to control the insulation and pre-charge fault detection unit 4 to read the pre-charge fault code fed back by the battery management system 5 under the high-voltage power-on control condition of the whole vehicle. By reading the pre-charge fault code, the insulation and pre-charge fault detection unit 4 can quickly locate the fault point; then, under the high-voltage power-off control condition of the whole vehicle, after controlling the insulation and pre-charge fault detection unit 4 to clear the pre-charge fault code, the insulation and pre-charge fault detection unit 4 is controlled to disconnect all high-voltage relays. When the high voltage is powered off, the pre-charge fault code is cleared to ensure that the next time the power is on, the system will not be misjudged or affect normal operation due to the previous fault code.

[0141] That is to say, controlling the operation of the insulation and pre-charge fault detection unit 4 during the vehicle high voltage power-on and power-off control process is to ensure the safety, stability and reliability of the high voltage system.

[0142] In S12 and S13, the resistance value and / or the tube voltage drop value of the electric vehicle busbar 9 are judged to identify which high-voltage component of the electric vehicle has failed.

[0143] The abnormal situation of the resistance value of the electric vehicle busbar 9 includes any one of the following: the positive / negative resistance value is different from the negative / positive resistance value, the ratio of the positive / negative resistance value to the negative / positive resistance value or the ratio of the negative / positive resistance value to the positive / negative resistance value is greater than a first threshold value, and the positive / negative resistance value and the negative / positive resistance value are greater than a second threshold value. Typically, the first threshold value is greater than 1000, and the second threshold value is greater than 2 megohms.

[0144] The abnormal conditions of the tube voltage drop value include any one of the following: the positive / negative tube voltage drop value is different from the negative / positive tube voltage drop value, the positive / negative tube voltage drop value is less than the third threshold and the negative / positive tube voltage drop value cannot be detected, and the positive / negative tube voltage drop value cannot be detected and the negative / positive tube voltage drop value is less than the third threshold. Usually, the third threshold is less than 1 volt.

[0145] Specifically, the pre-charge fault troubleshooting method includes the following steps:

[0146] Step 1: Under the condition of high-voltage power-on control of the vehicle, the operation is usually to turn the key to the On position + step on the foot brake pedal, and the insulation and pre-charge fault detection unit 4 reads the fault code detected by the battery management system 5 to check whether there is a pre-charge fault code. If there is, then go to step 2 under the condition of high-voltage power-off control of the vehicle;

[0147] Step 2: The insulation and pre-charge fault detection unit 4 gives an instruction to the battery management system 5 to clear the vehicle pre-charge fault code, and disconnects all high-voltage component relays after a period of time; under the high-voltage power-on control condition of the vehicle, the insulation and pre-charge fault detection unit 4 reads the voltage, insulation resistance and fault code in the power battery; if the voltage or insulation resistance in the power battery is abnormal or an insulation fault code appears, the insulation and pre-charge fault detection unit 4 determines that it is a pre-charge fault inside the power battery; if the above abnormality does not occur, go to step 3;

[0148] Step 3: The insulation and pre-charge fault detection unit 4 starts the pre-charge detection module 3 to determine the resistance value and / or tube voltage drop value of the electric vehicle bus 9;

[0149] Step 4: Control the insulation and pre-charge fault detection unit 4 to read the feedback result of the pre-charge detection module 3 after each closing of the high-voltage relay until the pre-charge detection module 3 detects that the resistance value and / or tube voltage drop value of the electric vehicle bus 9 is abnormal. Based on the resistance value and / or tube voltage drop value of the electric vehicle bus 9, the fault type of the electric vehicle is output as the pre-charge fault of the high-voltage component of the electric vehicle corresponding to the high-voltage relay when the resistance value and / or tube voltage drop value of the electric vehicle bus 9 is abnormal.

[0150] The rules for judging abnormal resistance and tube voltage drop are as follows:

[0151] The abnormal situation of the resistance value of the electric vehicle busbar 9 includes any one of the following: the positive / negative resistance value is different from the negative / positive resistance value, the ratio of the positive / negative resistance value to the negative / positive resistance value or the ratio of the negative / positive resistance value to the positive / negative resistance value is greater than the first threshold value, and the positive / negative resistance value and the negative / positive resistance value are greater than the second threshold value. Usually, the first threshold value is greater than 1000, and the second threshold value is greater than 2 megohms.

[0152] The abnormal conditions of the tube voltage drop value include any one of the following: the positive / negative tube voltage drop value is different from the negative / positive tube voltage drop value, the positive / negative tube voltage drop value is less than the third threshold and the negative / positive tube voltage drop value cannot be detected, and the positive / negative tube voltage drop value cannot be detected and the negative / positive tube voltage drop value is less than the third threshold. Usually, the third threshold is less than 1 volt.

[0153] An embodiment of the present invention provides a method for troubleshooting electric vehicle pre-charging faults. For details, see Figure 5 , Figure 5 A flowchart of a method for troubleshooting an insulation fault in an electric vehicle based on an electric vehicle pre-charging and insulation fault troubleshooting system in one embodiment of the present invention is shown, wherein the insulation resistance of the electric vehicle is less than a preset threshold and an insulation fault is reported. The method includes:

[0154] S21: Under the condition of high-voltage electric control of the whole vehicle, the insulation and pre-charge fault detection unit is controlled to read the first insulation fault code fed back by the battery management system. After the first insulation fault code is cleared, the insulation and pre-charge fault detection unit is controlled to read the second insulation fault code. If the second insulation fault code is the same as the first insulation fault code, it is determined to be a power battery insulation fault;

[0155] S22: When the insulation and pre-charge fault detection unit does not read the second insulation fault code, shield the vehicle controller and control the main positive relay and the main negative relay to close;

[0156] S23: Disconnect the high-voltage relays in sequence, control the insulation and pre-charge fault detection unit to read the insulation fault code and insulation resistance value fed back by the battery management system after each disconnection of the high-voltage relay, until the insulation fault code disappears and the insulation resistance value is within the preset threshold value, and output the fault type of the electric vehicle as the insulation fault of the high-voltage component of the electric vehicle corresponding to the high-voltage relay when the insulation fault code disappears and the insulation resistance value is within the preset threshold value.

[0157] In step S21, by comparing the second insulation fault code with the first insulation fault code, if the second insulation fault code is the same as the first insulation fault code, this usually means that there is a continuous insulation fault in the power battery. This process is an important part of the high-voltage electrical control process of electric vehicles. By reading and comparing the insulation fault code, the insulation fault of the power battery system can be discovered and handled in time to ensure the safety and reliability of the electric vehicle.

[0158] In step S22, after ensuring that the vehicle controller is shielded, close the main positive relay 7 and the main negative relay 8. These two relays are key components connecting the power battery and the high-voltage load. Their closure will allow the high-voltage system to be re-energized for further troubleshooting.

[0159] Among them, in step S22, if the high-voltage interlock failure fault function of the vehicle controller is not shielded, once the main positive relay 7 and the main negative relay 8 are closed, the whole vehicle will fail and alarm; in order to check which high-voltage component is faulty, it is necessary to first shield the high-voltage interlock failure fault function of the vehicle controller, and then execute the closing step of the main positive relay 7 and the main negative relay 8, so that the corresponding high-voltage component fault can be identified by disconnecting the high-voltage relay.

[0160] By closing the high-voltage relays in sequence and gradually troubleshooting and locating insulation faults, maintenance personnel can quickly find and repair faulty components, thereby restoring normal operation of the electric vehicle.

[0161] Specifically, the method for troubleshooting when the insulation resistance is less than the preset threshold and an insulation fault is reported includes the following steps:

[0162] Step 1: Under the condition of high-voltage power control of the whole vehicle, the insulation and pre-charge fault detection unit 4 reads the insulation fault code detected by the battery management system 5 to check whether there is an insulation resistance value less than a preset threshold value. If so, proceed to step 2;

[0163] Step 2: The insulation and pre-charge fault detection unit 4 gives an instruction to the battery management system 5 to clear the insulation fault code. After a period of time, the insulation and pre-charge fault detection unit 4 reads the insulation fault code fed back by the battery management system 5; if the insulation fault code is the same as that in step 1, the insulation and pre-charge fault detection unit 4 determines that it is a power battery insulation fault; if the above abnormality does not occur, go to step 3;

[0164] Step 3: The insulation and pre-charge fault detection unit 4 shields the vehicle controller and controls the main positive relay 7 and the main negative relay 8 to close;

[0165] Step 4: The insulation and pre-charge fault detection unit 4 reads the insulation fault code and insulation resistance value fed back by the battery management system 5 to check whether the insulation resistance value of the whole vehicle is less than the preset threshold value and the insulation fault code. If so, proceed to step 5;

[0166] Step 5: The insulation and pre-charge fault detection unit 4 sends an instruction to the battery management system 5 to clear the insulation fault code. After a period of time, the insulation and pre-charge fault detection unit 4 controls the disconnection of the first high-voltage relay. After a period of time, check whether the insulation fault code appears. If the insulation fault code still appears, go to step 6;

[0167] Step six: The insulation and pre-charge fault detection unit 4 gives an instruction to the battery management system 5 to clear the insulation fault code, and controls the insulation and pre-charge fault detection unit 4 to read the insulation fault code and insulation resistance value fed back by the battery management system 5 after each closing of the high-voltage relay until the insulation fault code disappears and the insulation resistance value is within the preset threshold value, and outputs the fault type of the electric vehicle as the insulation fault of the high-voltage component of the electric vehicle corresponding to the high-voltage relay when the insulation fault code disappears and the insulation resistance value is within the preset threshold value.

[0168] An embodiment of the present invention provides a method for troubleshooting electric vehicle pre-charging faults. For details, see Figure 6 , Figure 6 The flowchart of a method for troubleshooting an electric vehicle insulation resistance value less than a preset threshold value and not reporting an insulation fault based on an electric vehicle pre-charging and insulation fault troubleshooting system in one embodiment of the present invention is shown, and the method includes:

[0169] S31: Under the condition of high-voltage power control of the whole vehicle, control the insulation and pre-charge fault detection unit to read the first insulation resistance value fed back by the battery management system, and determine whether the first insulation resistance value is less than a preset threshold value and no insulation fault code appears;

[0170] S32: When the insulation and pre-charge fault detection unit detects that the first insulation resistance is less than a preset threshold and no insulation fault code appears, the first insulation resistance is refreshed, and the insulation and pre-charge fault detection unit is controlled to read the second insulation resistance fed back by the battery management system. If the second insulation resistance is less than the preset threshold and no insulation fault code appears, it is determined to be a power battery insulation fault;

[0171] S33: After starting the secondary insulation detection module, injecting insulation detection voltage into the electric vehicle bus through the boost chopper circuit and controlling the insulation and pre-charge fault detection unit to read the insulation resistance feedback from the secondary insulation detection module, the high-voltage relays are disconnected in sequence. When the insulation resistance is less than the preset threshold, the insulation and pre-charge fault detection unit is controlled to read the insulation resistance feedback from the battery management system after each disconnection of the high-voltage relay until the insulation fault code disappears and the insulation resistance is within the preset threshold. The fault type of the electric vehicle is output as the insulation fault of the high-voltage component of the electric vehicle corresponding to the high-voltage relay when the insulation fault code disappears and the insulation resistance is within the preset threshold.

[0172] In steps S31 and S32, by comparing the insulation resistance values, if the second insulation resistance value is the same as the first insulation resistance value, it indicates that there is a fault of low insulation resistance value of the power battery, and the power battery needs to be repaired.

[0173] Low insulation resistance of power batteries may be caused by a variety of reasons: internal battery structure problems, battery short circuit, installation problems or system vibration, which need to be repaired to ensure the safe and reliable operation of the electric vehicle's high-voltage system.

[0174] In step S33, when it is suspected that there is a problem with the insulation performance of the power battery, the secondary insulation detection module 6 is started. The secondary insulation detection module 6 injects a specific insulation detection voltage into the electric vehicle bus 9 through a boost chopper circuit. This voltage is usually higher than the normal working voltage, so as to more accurately detect the performance of the insulation layer. After the insulation detection voltage is injected, the insulation and pre-charge fault detection unit 4 will read the insulation resistance feedback from the secondary insulation detection module 6. This resistance reflects the current insulation state of the power battery system.

[0175] The read insulation resistance is compared with the preset threshold. If the insulation resistance is less than the threshold, it means that there is a problem with the insulation performance of the power battery and further investigation is needed. In order to determine the specific component that causes the low insulation resistance, it is necessary to gradually disconnect the high-voltage relay and read the insulation resistance feedback from the battery management system 5 after each disconnection. The purpose of this step is to find out the component that causes the low insulation resistance through gradual investigation.

[0176] The insulation resistance is continuously read until the insulation resistance reaches within the preset threshold value, which indicates that the component causing the low insulation resistance has been found and the fault has been eliminated by disconnecting the corresponding high-voltage relay.

[0177] Once the component causing the low insulation resistance is determined, the insulation and pre-charge fault detection unit 4 will output the fault type and location. Specifically, it will indicate at which time the insulation resistance returns to normal after the high-voltage relay is disconnected, thereby determining the high-voltage component causing the insulation fault. According to the output fault type and location, maintenance personnel can take corresponding measures to repair or replace the faulty component. For example, if it is determined that the insulation layer of a high-voltage cable is damaged and causes the fault, then the cable needs to be replaced.

[0178] Specifically, the method for troubleshooting when the insulation resistance is less than the preset threshold and no insulation fault is reported includes the following steps:

[0179] Step 1: Under the condition of high-voltage power control of the whole vehicle, the insulation and pre-charge fault detection unit 4 reads the insulation fault code and insulation resistance detected by the battery management system 5 to check whether there is an insulation resistance value less than a preset threshold. If so, proceed to step 2;

[0180] Step 2: The insulation and pre-charge fault detection unit 4 gives an instruction to the battery management system 5 to refresh the insulation resistance value. After a period of time, the insulation and pre-charge fault detection unit 4 reads the insulation resistance value fed back by the battery management system 5 to confirm whether the insulation resistance value is less than a preset threshold value; if the insulation resistance value is less than the preset threshold value and no insulation fault code appears, the insulation and pre-charge fault detection unit 4 determines that it is a power battery insulation fault; if the above abnormality does not occur, proceed to step 3;

[0181] Step 3: The insulation and pre-charge fault detection unit 4 starts the secondary insulation detection module 6, injects insulation detection voltage into the busbar through the boost chopper circuit and controls the insulation and pre-charge fault detection unit 4 to read the insulation resistance feedback from the secondary insulation detection module 6, and then confirms whether the actual insulation resistance of the vehicle is less than the preset threshold. If the measured insulation resistance is less than the preset threshold, proceed to step 4;

[0182] Step 4: The insulation and pre-charge fault detection unit 4 controls the disconnection of the first high-voltage relay, and checks whether the insulation resistance is less than the preset threshold after a period of time. If the insulation resistance is still less than the preset threshold, proceed to step 5;

[0183] Step 5: Control the insulation and pre-charge fault detection unit 4 to read the insulation resistance value fed back by the battery management system 5 after each disconnection of the high-voltage relay until the insulation fault code disappears and the insulation resistance value is within the preset threshold value, and output the fault type of the electric vehicle as an insulation fault in the high-voltage component of the electric vehicle corresponding to the high-voltage relay when the insulation fault code disappears and the insulation resistance value is within the preset threshold value.

[0184] An embodiment of the present invention provides an electric vehicle, which includes any one of the electric vehicle fault troubleshooting systems or the electric vehicle is used to implement any one of the electric vehicle fault troubleshooting methods.

[0185] Specifically, electric vehicles can be pure electric vehicles, hybrid electric vehicles and fuel cell vehicles. Among them, pure electric vehicles are vehicles that are completely powered by electricity, hybrid electric vehicles combine two power sources, an internal combustion engine and an electric motor, and fuel cell vehicles use fuel cells to generate electricity to drive the vehicle.

[0186] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An electric vehicle fault troubleshooting system, characterized in that: It includes a pre-charge detection module and a pre-charge detection loop module connected in parallel to the electric vehicle bus; The pre-charge detection circuit module includes a plurality of pre-charge detection branches connected in parallel, each of which is connected to the electric vehicle bus, and each of which includes a high-voltage component and a high-voltage relay for controlling the on and off of the current pre-charge detection branch; The detection end of the pre-charge detection module is connected to the electric vehicle bus, and the power supply end of the pre-charge detection module is connected to the electric vehicle battery system. The pre-charge detection module is used to perform pre-charge fault troubleshooting on the high-voltage component corresponding to the high-voltage relay according to the resistance value and / or tube voltage drop value of the electric vehicle bus.

2. The electric vehicle fault troubleshooting system according to claim 1, characterized in that: The electric vehicle fault troubleshooting system also includes a secondary insulation detection module, a main positive relay and a main negative relay; The detection end of the secondary insulation detection module is connected to the positive pole of the electric vehicle bus through the main positive relay, and the detection end of the secondary insulation detection module is also connected to the negative pole of the electric vehicle bus through the main negative relay. The power supply end of the secondary insulation detection module is connected to the external electric vehicle battery system, and the secondary insulation detection module is used to control the selected high-voltage relay to realize insulation fault detection of the high-voltage component.

3. A method for troubleshooting electric vehicle, characterized in that: Applied in the electric vehicle fault troubleshooting system according to any one of claims 1 to 2, the electric vehicle fault troubleshooting method comprises: When a pre-charge fault code is detected, the pre-charge fault troubleshooting mode is entered; According to the detected power battery voltage value and insulation resistance value of the electric vehicle battery system, determine whether there is a power battery internal pre-charging fault; When the fault does not belong to the internal pre-charging fault of the power battery, it is determined whether a high-voltage component pre-charging fault occurs according to the resistance value and / or tube voltage drop value of the electric vehicle busbar.

4. The electric vehicle fault troubleshooting method according to claim 3, characterized in that: After disconnecting all the high-voltage relays, if an insulation fault code is read, an abnormal voltage in the power battery is detected, or an abnormal insulation resistance is detected, it is determined that an internal pre-charging fault of the power battery occurs.

5. The electric vehicle fault troubleshooting method according to claim 4, characterized in that: When the insulation fault code is not read, the voltage abnormality in the power battery is not detected, or the insulation resistance abnormality is not detected, the pre-charge detection module is started; After starting the pre-charge detection module, closing each of the high-voltage relays in sequence, and reading the feedback results of the pre-charge detection module after each closure, until the pre-charge detection module detects that the resistance value and / or the tube voltage drop value of the electric vehicle busbar are abnormal; When it is detected that the resistance value and / or the tube voltage drop value of the electric vehicle busbar is abnormal, it is determined that the high-voltage component pre-charging fault occurs in the corresponding high-voltage component.

6. The electric vehicle fault troubleshooting method according to claim 4, characterized in that: Before disconnecting all the high-voltage relays, the electric vehicle fault troubleshooting method further includes: Under the condition of high voltage power-on control of the whole vehicle, reading the pre-charge fault code; Under the condition of high-voltage power control of the whole vehicle, after clearing the pre-charge fault code, all the high-voltage relays are disconnected.

7. The electric vehicle fault troubleshooting method according to claim 5, characterized in that: The abnormal situation of the resistance value of the electric vehicle busbar includes any one of the following: the positive / negative resistance value is different from the negative / positive resistance value, the ratio of the positive / negative resistance value to the negative / positive resistance value or the ratio of the negative / positive resistance value to the positive / negative resistance value is greater than a first threshold, and the positive / negative resistance value and the negative / positive resistance value are greater than a second threshold; The abnormal conditions of the tube pressure drop value include any one of the following: the positive / negative tube pressure drop value is different from the negative / positive tube pressure drop value, the positive / negative tube pressure drop value is less than the third threshold and the negative / positive tube pressure drop value cannot be detected, and the positive / negative tube pressure drop value cannot be detected and the negative / positive tube pressure drop value is less than the third threshold.

8. The electric vehicle fault troubleshooting method according to claim 4, further comprising: After detecting that the insulation resistance is less than the first preset value and reading the insulation fault code, determining that the first insulation fault troubleshooting mode is satisfied, and determining whether a power battery insulation fault or a high-voltage component insulation fault occurs according to the action feedback information of the insulation fault code read; and, After detecting that the insulation resistance is less than the second preset value and the insulation fault code is not read, it is determined that the second insulation fault troubleshooting mode is satisfied, and based on the action feedback information of the insulation resistance read, it is determined whether a power battery insulation fault or a high-voltage component insulation fault occurs.

9. The electric vehicle fault troubleshooting method according to claim 8, characterized in that: The determining that the first insulation fault troubleshooting mode is satisfied and determining whether a power battery insulation fault or a high-voltage component insulation fault occurs according to the action feedback information of the insulation fault code read includes: When the first insulation fault troubleshooting mode is satisfied, if the insulation fault code is detected to reappear after the insulation fault code is cleared, it is determined that the type of the insulation fault is the power battery insulation fault; and, When the first insulation fault troubleshooting mode is met, if the insulation fault code is not detected to reappear after clearing the insulation fault code, the insulation fault code reappearance action is executed, and each of the high-voltage relays is disconnected in turn until the insulation fault code is not detected to reappear and / or the insulation resistance is detected to meet the first preset, and it is determined that the current corresponding high-voltage component has the high-voltage component insulation fault, wherein the insulation fault code reappearance action includes shielding the vehicle controller, and controlling the main positive relay and the main negative relay in the electric vehicle fault troubleshooting system to close.

10. The electric vehicle fault troubleshooting method according to claim 8, characterized in that: The determining that the second insulation fault troubleshooting mode is satisfied and determining whether a power battery insulation fault or a high-voltage component insulation fault occurs according to the read action feedback information of the insulation resistance value includes: When the second insulation fault troubleshooting mode is satisfied, if the insulation resistance is detected to reappear after the insulation resistance is cleared, it is determined that the type of the insulation fault is the power battery insulation fault; and, When the second insulation fault troubleshooting mode is met, if the insulation resistance is not detected to reappear after clearing the insulation resistance, the insulation resistance reappearance action is executed, and each of the high-voltage relays is closed in turn until the detected insulation resistance meets the second preset, and it is determined that the current corresponding high-voltage component has the high-voltage component insulation fault, wherein the insulation resistance reappearance action includes operating the secondary insulation detection module in the electric vehicle fault troubleshooting system.

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