WO2023221595A1 - 电动汽车绝缘检测功能的失效诊断系统、方法及设备 - Google Patents

电动汽车绝缘检测功能的失效诊断系统、方法及设备 Download PDF

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Publication number
WO2023221595A1
WO2023221595A1 PCT/CN2023/078382 CN2023078382W WO2023221595A1 WO 2023221595 A1 WO2023221595 A1 WO 2023221595A1 CN 2023078382 W CN2023078382 W CN 2023078382W WO 2023221595 A1 WO2023221595 A1 WO 2023221595A1
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WIPO (PCT)
Prior art keywords
detection resistor
electric vehicle
switch
detection
insulation
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PCT/CN2023/078382
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English (en)
French (fr)
Inventor
沈小杰
廖增成
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深圳市道通合创数字能源有限公司
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Publication of WO2023221595A1 publication Critical patent/WO2023221595A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass

Definitions

  • the embodiments of the present application relate to the technical field of electric vehicles, and in particular to a failure diagnosis system, method and equipment for the insulation detection function of electric vehicles.
  • electric energy in electric vehicles can solve the problems of energy consumption and greenhouse gas emissions caused by traditional oil vehicles, achieve energy conservation and emission reduction, and achieve environmentally friendly and sustainable development.
  • the working voltage of most passenger car models is 400V, and high-end models have introduced 800V working voltage.
  • the working voltage of some large heavy-duty electric vehicles has reached more than 1,000V.
  • the main technical problem solved by the embodiments of this application is to provide a failure diagnosis system, method and equipment for the insulation detection function of electric vehicles, which can accurately diagnose whether the insulation detection function of electric vehicles has failed, discover functional failure problems in a timely manner, and improve safety.
  • a failure diagnosis system for the insulation detection function of electric vehicles including a communication-connected diagnostic device and a server.
  • the diagnostic device includes a DC bus, N detection Resistor group and equipment ground, N detection resistor groups correspond to N resistance ranges one by one, each detection resistor group includes a positive detection resistor and a negative detection resistor, the positive detection resistor passes through the first switch Connect the positive terminal of the DC bus and the device ground, and the negative detection resistor connects the negative terminal of the DC bus and the device ground through a second switch, where N is an integer greater than or equal to 1;
  • the positive terminal of the DC bus is used to connect the positive terminal of the battery of the electric vehicle, the negative terminal of the DC bus is used to connect the negative terminal of the battery of the electric vehicle, and the diagnostic device is also used to communicate with the electric vehicle;
  • the diagnosis The device controls the switch connected to any one of the positive detection resistor and the negative detection resistor to close each time, and the switch is one of the
  • the diagnostic device controls the switch to close, it reads the measured resistance value of the detection resistor fed back by the electric vehicle;
  • the diagnostic device determines the measurement deviation of the electric vehicle for the detection resistor based on the measured resistance value of the detection resistor and the actual resistance value of the detection resistor;
  • the diagnostic device uploads the measurement deviation to the server, and the server determines that the insulation detection function of the electric vehicle is normal or failed based on at least one measurement deviation of the electric vehicle for the detection resistor.
  • the diagnostic device sequentially controls the first switch and the second switch corresponding to one of the N detection resistor groups to close, the diagnostic device then sequentially controls the The first switch and the second switch corresponding to the next detection resistor group among the N detection resistor groups are closed;
  • the diagnostic device uploads the measurement deviations corresponding to the N detection resistor groups to the server, and the server determines whether the insulation detection function of the electric vehicle is normal or failed based on the measurement deviations corresponding to the N detection resistor groups. .
  • the insulation detection function of the electric vehicle is determined. Failure, the target measurement deviation is any one of the measurement deviations corresponding to the N detection resistor groups.
  • the diagnostic device sequentially controls the first switch and the second switch corresponding to one of the N detection resistor groups to close, the diagnostic device then sequentially controls the The first switch and the second switch corresponding to the next detection resistor group among the N detection resistor groups are closed;
  • the diagnostic device Each time the diagnostic device obtains at least one measurement deviation corresponding to a detection resistance group, it uploads at least one measurement deviation corresponding to the detection resistance group to the server. Measure the deviation to determine whether the insulation detection function of the electric vehicle is normal or failed.
  • the diagnostic device sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close. After combining, read the feedback information of the electric vehicle;
  • the diagnostic device determines whether the insulation detection function of the electric vehicle is normal or failed based on the feedback information.
  • the diagnostic device uploads at least one of the feedback information to the server, and the server determines that the insulation monitoring function of the electric vehicle is normal or failed based on at least one of the feedback information.
  • the server detects an alarm anomaly in at least one of the feedback information for a second preset number of consecutive times, it is determined that the insulation detection function of the electric vehicle fails.
  • the diagnostic device further includes a voltmeter connected between the positive terminal and the negative terminal of the DC bus;
  • the diagnostic equipment sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, if the voltage measured by the voltmeter is read as 0, the insulation detection of the electric vehicle is determined. functioning normally.
  • the diagnostic device before the diagnostic device sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, the diagnostic device reads the voltage measured by the voltmeter. If the If the voltage is the normal output voltage of the battery, it prompts the control to close the switch to perform diagnostic work.
  • the system further includes a vehicle communication interface device, which is used to communicatively connect the diagnostic device and the electric vehicle.
  • a diagnostic device which includes a DC bus, N detection resistor groups, a device ground, a processor and a communication module;
  • N detection resistor groups correspond to N resistance ranges one by one.
  • Each detection resistor group includes a positive detection resistor and a negative detection resistor.
  • the positive detection resistor is connected to the DC through a first switch.
  • the positive terminal of the bus and the device ground, the negative detection resistor is connected to the negative terminal of the DC bus and the device ground through a second switch, where N is an integer greater than or equal to 1;
  • the positive terminal of the DC bus is used to connect the positive terminal of the battery of the electric vehicle
  • the negative terminal of the DC bus is used to connect the negative terminal of the battery of the electric vehicle
  • the communication module is used for communication connection with the electric vehicle
  • the processor controls the switch connected to any one of the positive detection resistor and the negative detection resistor to close each time, and the switch is one of the first switch and the second switch;
  • the communication module reads the measured resistance value of the detection resistor fed back by the electric vehicle;
  • the processor determines the measurement deviation of the electric vehicle for the detection resistor based on the measured resistance of the detection resistor and the actual resistance of the detection resistor;
  • the processor determines that the insulation detection function of the electric vehicle is normal or failed based on at least one measurement deviation of the electric vehicle with respect to the detection resistor.
  • the processor sequentially controls the first switch and the second switch corresponding to one of the N sensing resistor groups to close, the processor then sequentially controls the The first switch and the second switch corresponding to the next detection resistor group among the N detection resistor groups are closed;
  • the processor determines whether the insulation detection function of the electric vehicle is normal or invalid based on the measurement deviations corresponding to the N detection resistor groups.
  • the processor detects a target measurement deviation greater than or equal to a deviation threshold among the measurement deviations corresponding to the N detection resistor groups for a first preset number of times, the insulation detection of the electric vehicle is determined.
  • the function fails, and the target measurement deviation is any one of the measurement deviations corresponding to the N detection resistor groups.
  • the processor sequentially controls the first switch and the second switch corresponding to one of the N sensing resistor groups to close, the processor then sequentially controls the The first switch and the second switch corresponding to the next detection resistor group among the N detection resistor groups are closed;
  • the processor Each time the processor obtains at least one measurement deviation corresponding to a detection resistor group, it determines whether the insulation detection function of the electric vehicle is normal or failed based on the at least one measurement deviation corresponding to the detection resistor group.
  • the processor sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, and then reads the feedback information of the electric vehicle;
  • the insulation detection function of the electric vehicle is normal or failed.
  • the processor detects an alarm anomaly in at least one of the feedback information for a second preset number of consecutive times, it is determined that the insulation detection function of the electric vehicle has failed.
  • the diagnostic device further includes a voltmeter connected between the positive terminal and the negative terminal of the DC bus;
  • the processor sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, if all the If the voltage measured by the voltmeter is 0, it is determined that the insulation detection function of the electric vehicle is normal.
  • the communication module reads the voltage measured by the voltmeter. If If the voltage is the normal output voltage of the battery, the processor prompts the control to close the switch to perform diagnostic work.
  • a diagnostic device which includes a DC bus, N detection resistor groups, a device ground, a processor and a communication module;
  • N detection resistor groups correspond to N resistance ranges one by one.
  • Each detection resistor group includes a positive detection resistor and a negative detection resistor.
  • the positive detection resistor is connected to the DC through a first switch.
  • the positive terminal of the bus and the device ground, the negative detection resistor is connected to the negative terminal of the DC bus and the device ground through a second switch, where N is an integer greater than or equal to 1;
  • the positive terminal of the DC bus is used to connect the positive terminal of the battery of the electric vehicle
  • the negative terminal of the DC bus is used to connect the negative terminal of the battery of the electric vehicle
  • the communication module is used to communicate with the server and the electric vehicle respectively.
  • the processor controls the switch connected to any one of the positive detection resistor and the negative detection resistor to close each time, and the switch is one of the first switch and the second switch;
  • the communication module reads the measured resistance value of the detection resistor fed back by the electric vehicle;
  • the processor determines the measurement deviation of the electric vehicle for the detection resistor based on the measured resistance of the detection resistor and the actual resistance of the detection resistor;
  • the communication module uploads the measurement deviation to the server, so that the server determines that the insulation detection function of the electric vehicle is normal or invalid based on at least one measurement deviation of the electric vehicle for the detection resistor.
  • the processor sequentially controls the first switch and the second switch corresponding to one of the N sensing resistor groups to close, the processor then sequentially controls the The first switch and the second switch corresponding to the next detection resistor group among the N detection resistor groups are closed;
  • the communication module uploads the measurement deviations corresponding to the N detection resistor groups to the server, so that the server determines that the insulation detection function of the electric vehicle is normal based on the measurement deviations corresponding to the N detection resistor groups. or failure.
  • the processor detects a target measurement deviation greater than or equal to a deviation threshold among the measurement deviations corresponding to the N detection resistor groups for a first preset number of times, the insulation detection of the electric vehicle is determined.
  • the function fails, and the target measurement deviation is any one of the measurement deviations corresponding to the N detection resistor groups.
  • the processor sequentially controls the first switch and the second switch corresponding to one of the N sensing resistor groups to close, the processor then sequentially controls the The first switch and the second switch corresponding to the next detection resistor group among the N detection resistor groups are closed;
  • the communication module uploads at least one measurement deviation corresponding to the detection resistance group to the server, so that the server can At least one measurement deviation corresponding to the resistance group determines whether the insulation detection function of the electric vehicle is normal or failed.
  • the processor sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, and then reads the feedback information of the electric vehicle;
  • the processor determines whether the insulation detection function of the electric vehicle is normal or invalid based on the feedback information.
  • the communication module uploads at least one of the feedback information to the server, so that the server determines that the insulation monitoring function of the electric vehicle is normal or invalid based on at least one of the feedback information.
  • the server detects an alarm anomaly in at least one of the feedback information for a second preset number of consecutive times, it is determined that the insulation detection function of the electric vehicle fails.
  • the diagnostic device further includes a voltmeter connected between the positive terminal and the negative terminal of the DC bus;
  • the processor sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, if the communication module respectively reads the voltage measured by the voltmeter as 0, then the processor It is determined that the insulation detection function of the electric vehicle is normal.
  • the communication module reads the voltage measured by the voltmeter. If If the voltage is the normal output voltage of the battery, the processor prompts the control to close the switch to perform diagnostic work.
  • embodiments of the present application provide a charging pile, including the diagnostic device of the first aspect or the diagnostic device of the second aspect.
  • the failure diagnosis system for the insulation detection function of electric vehicles includes a communication-connected diagnostic device and a server, where the diagnostic device includes a DC bus, N detection resistor group and Equipment ground, N detection resistor groups correspond to N resistance areas one by one.
  • Each detection resistor group includes a positive detection resistor and a negative detection resistor.
  • the positive detection resistor is connected to the positive terminal of the DC bus and the equipment ground through the first switch.
  • the negative detection resistor is connected to the negative terminal of the DC bus and the equipment ground through the second switch.
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle
  • the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle
  • the diagnostic equipment is connected to the electric vehicle for communication.
  • the diagnostic equipment controls the switch connected to any one of the positive detection resistor and the negative detection resistor to close each time, and the switch is one of the first switch and the second switch.
  • the diagnostic equipment reads the measured resistance value of the detection resistor fed back by the electric vehicle.
  • the diagnostic equipment determines the measurement deviation of the electric vehicle for the detection resistor based on the measured resistance value of the detection resistor and the actual resistance value of the detection resistor.
  • the diagnostic device uploads the measurement deviation to the server, and the server determines whether the insulation detection function of the electric vehicle is normal or failed based on at least one measurement deviation of the electric vehicle for the detection resistor.
  • the diagnostic equipment can accurately detect the measurement deviation of the electric vehicle's external resistance. Based on the measurement deviation, the server can determine whether the electric vehicle's detection of the external resistance is accurate. If the measurement is accurate, the insulation detection function is normal. If the measurement is not accurate, the insulation detection function is normal. If it is accurate, the insulation detection function will fail. Based on the fact that N detection resistor groups correspond to N resistance ranges one by one, in multiple diagnoses, the diagnostic system can detect the measurement accuracy of the electric vehicle's resistance in each resistance range, making the diagnosis results more accurate.
  • Figure 1 is a schematic structural diagram of a battery management system of a battery in some embodiments of the present application
  • Figure 2 is a schematic structural diagram of a failure diagnosis system for the insulation detection function of an electric vehicle in some embodiments of the present application;
  • Figure 3 is a schematic structural diagram of a diagnostic device in some embodiments of the present application.
  • the insulation detection function of electric vehicles is first introduced.
  • This insulation detection function mainly relies on the battery management system (BATTERY MANAGEMENT SYSTEM, BMS) that comes with the battery to detect the insulation resistance of the battery's positive electrode to ground and negative electrode to ground. If the insulation resistance of the battery's positive electrode to ground and negative electrode to ground is large, the insulation between the battery and the external environment will be better. If the insulation resistance of the battery's positive electrode to ground and negative electrode to ground is small, and there is a risk of electric shock caused by leakage, the battery management system needs to report an alarm message and cut off the battery's power output in a timely manner.
  • the power supply output terminals here can be the positive and negative poles of the battery, and the positive and negative poles are connected to the DC bus inside the electric vehicle to supply power to the drive system.
  • a battery 100 includes a battery body 10 and a battery management system 20 .
  • the battery body 10 can be a battery cell or one or more battery cell modules.
  • the battery management system 20 includes a voltage sampling module 21, a current sampling module 22, an insulation detection module 23, a temperature sensor 24, a controller 25, a switching circuit 26, and so on.
  • the voltage sampling module 21 is used to collect the voltage, passive balancing power, etc. of the battery body 10 in real time.
  • the current sampling module 22 is used to sample the current of the battery body 10 during the charging and discharging process.
  • Insulation detection module 23 is used to detect batteries The insulation resistance between the positive pole and the ground and the negative pole of the main body 10. If the resistance value is larger, the insulation between the positive electrode and the ground and the negative electrode of the battery body 10 is better, and the insulation between the battery and the external environment is better.
  • the temperature sensor 24 is used to collect the temperature of the battery body 10 in real time.
  • the above-mentioned voltage sampling module 21, current sampling module 22 and insulation detection module 23 can be implemented by existing chip modules (such as integrated circuit IC) or conventional circuits in the field.
  • the voltage sampling module 21 will not be introduced in detail here.
  • the temperature sensor 24 can be implemented by an existing thermal resistor or thermocouple, and the structure and principle of the temperature sensor 24 will not be described in detail here.
  • the voltage sampling module 21, the current sampling module 22 and the insulation detection module 23 transmit the collected data to the controller 25 (MCU).
  • the controller 25 determines the required undervoltage, overvoltage and overcurrent of the battery 100 based on the collected data. , short circuit, over temperature, low temperature, insulation resistance and other abnormal conditions, and then control the switch circuit 26 to selectively disconnect or connect the battery 100 and the external device 30 (load, charger) according to the determined protection measures. or diagnostic equipment, etc.) to implement the determined protective measures.
  • the vehicle-end BMS insulation detection mainly includes the bridge method and the signal injection method.
  • the bridge method is to obtain the rest time and insulation resistance from the change of the external insulation environment to the time when the electrical environment reaches a steady state when the external insulation environment changes. After the external insulation environment changes to varying degrees, it can accurately and accurately calculate the insulation resistance. Get the standing time and calculate the insulation resistance in time to ensure timely response to changes in the external insulation environment and avoid threats to the user's personal safety.
  • the signal injection method is that the insulation detection system selects an appropriate PWM pulse signal based on the total voltage of the battery pack and injects it into the high-voltage electrical subsystem of the electric vehicle, and then collects the voltage signals on both sides of the sampling resistor to calculate the insulation resistance value of the electric vehicle.
  • the insulation resistance of the battery's positive pole to ground or negative pole to ground is detected to be less than 100 ⁇ /V, it is determined to be a serious non-insulation fault, and the vehicle's high-voltage system (i.e. battery) should immediately stop output and alert the driver. personnel.
  • the main factors that lead to poor insulation and high-voltage leakage include collision, damage, leakage, moisture, corrosion, etc. These factors occur slowly and with a low probability of occurrence, and these factors will also cause the insulation detection function of the BMS to fail.
  • reasons such as communication failures and measurement errors will also cause the insulation detection function to fail to protect or alarm normally.
  • some vehicles may be used for several years or travel hundreds of thousands of kilometers without any insulation problems.
  • the vehicle insulation detection function itself lacks detection. When a real high-voltage leakage hazard occurs, the system may falsely report or even not report an alarm. In severe cases, causing casualties.
  • FIG. 2 is a schematic structural diagram of a failure diagnosis system for the insulation detection function of an electric vehicle in some embodiments of the present application.
  • the system includes a communication-connected diagnostic device and a server.
  • the server can be a local physical server or a cloud device, such as a cloud server, cloud host, cloud service platform, cloud computing platform, etc.
  • the server is a cloud platform.
  • the cloud platform communicates with diagnostic equipment through wireless networks such as 4G, 5G or WIFI.
  • the communication protocols followed by the two may be TCP/IP, NETBEUI, IPX/SPX and other protocols.
  • the server can be communicated and connected with multiple diagnostic devices. Therefore, electric vehicles use different diagnostic devices in different places to diagnose the insulation detection function. Each diagnostic device can upload diagnostic data to the server, and the server determines the diagnosis based on the diagnostic data. result. Therefore, the historical diagnosis results corresponding to electric vehicles can be saved on the server for easy viewing. In addition, they are not restricted by the location of the diagnostic equipment. Electric vehicles can be diagnosed at any time wherever diagnostic equipment is available, without the need to go to a location each time. More flexible.
  • the diagnostic equipment in the failure diagnosis system can be a diagnostic equipment dedicated to automobile repair points. It not only has the insulation detection function, but also can detect automobile faults. Users can use it to quickly read faults in the automobile electronic control system. , and displays fault information through the LCD screen to quickly identify the location and cause of the fault.
  • the diagnostic equipment in the failure diagnosis system can be integrated into the charging pile to regularly diagnose whether the insulation detection function is effective before or after charging the electric vehicle, and timely discover the insulation detection function failure problem, which improves convenience and timeliness. sex.
  • the diagnostic equipment includes a DC bus, N detection resistor groups and equipment ground.
  • N detection resistor groups correspond to N resistance value areas one-to-one
  • each detection resistor group includes a positive detection resistor and a negative detection resistor.
  • Each positive detection resistor is connected to the positive terminal of the DC bus and the equipment ground through the first switch
  • each negative detection resistor is connected to the negative terminal of the DC bus and the equipment ground through the second switch.
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle
  • the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle.
  • the equipment ground refers to the equipment shell that can be touched by users.
  • N is an integer greater than or equal to 1.
  • N can be 4, then there are 4 detection resistor groups with different resistance ranges, including 4 positive detection resistors with different resistances and 4 negative poles with different resistances. Detection resistor.
  • the number of first switches can be determined based on the type. For example, if the first switch is a single-pole switch, then a positive detection resistor is connected to the positive terminal of the DC bus and the device ground through a first switch. If the first switch is a single-pole double-throw switch, then The two positive detection resistors are connected to the positive terminal of the DC bus and the device ground through a first switch.
  • the number of second switches can be determined based on the type.
  • the second switch is a single-pole switch
  • a negative sense resistor is connected to the positive terminal of the DC bus and the device ground through a second switch.
  • the two negative sense resistors connect the positive terminal of the DC bus to device ground through a second switch.
  • Figure 2 simplifies the diagram showing that the positive detection resistor Rpi and the corresponding first switch Kpi in any detection resistor group are connected between the positive terminal of the DC bus and the device ground, and the negative detection resistor Rni and the corresponding second switch Kni are connected between the DC bus and the device ground. between the negative terminal of the current bus and device ground.
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle, and the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle.
  • the first switch Kpi is closed, it is equivalent to connecting the positive terminal of the battery and the vehicle.
  • a positive detection resistor Rpi is connected between the ground.
  • the second switch Kni is closed, it is equivalent to connecting a negative detection resistor Rni between the negative electrode of the battery and the vehicle ground.
  • the vehicle ground refers to the vehicle shell that users can touch. It can be understood that the vehicle ground and the equipment ground are both ground terminals, and the equipment ground can be equal to the vehicle ground.
  • the insulation resistance of the battery's positive electrode to the ground and the insulation resistance of the negative electrode to the ground are infinite to achieve the insulation protection effect.
  • Both the positive detection resistance and the negative detection resistance are smaller than the insulation resistance of the battery's positive electrode to ground and the insulation resistance of the negative electrode to ground. Therefore, when any switch is closed, it is equivalent to connecting a detection resistor between the battery and the vehicle ground, so that the battery is not insulated from the ground.
  • the insulation detection module 23 of the battery management system will detect the resistance of the battery to ground. If it is found that the resistance is small and the insulation is poor, and there is a risk of electric leakage and electric shock, the battery management system will report an alarm message and promptly cut off the power supply of the battery. output terminal.
  • the vehicle insulation detection function will trigger a serious fault when the quantitative value of the system insulation resistance measured is lower than 100 ⁇ /V.
  • the system insulation resistance A slight alarm will be triggered when the quantitative value is between 100 ⁇ /V and 500 ⁇ /V.
  • the quantitative value of the system insulation resistance refers to the smaller value of the insulation resistance between the positive electrode and the ground or the negative electrode and the ground. It is understandable that for vehicles with different operating voltages, the quantitative values of system insulation resistance are also different.
  • N detection resistor groups with different resistance ranges are set up (taking N as 4 as an example), covering 4 resistance ranges. For example, select one resistance value from each of the four resistance ranges: 0 ⁇ /V ⁇ 100 ⁇ /V, 100 ⁇ /V ⁇ 500 ⁇ /V, 500 ⁇ /V ⁇ 2000 ⁇ /V, and greater than 2000 ⁇ /V as the positive detection resistor and negative detection resistor. The resistance of the resistor.
  • the resistance values of the four positive detection resistors and the four negative detection resistors are distributed between 0 ⁇ /V ⁇ 100 ⁇ /V, 100 ⁇ /V ⁇ 500 ⁇ /V, 500 ⁇ /V ⁇ 2000 ⁇ /V and greater than 2000 ⁇ /V
  • vehicles with different operating voltages have different quantitative values of system insulation resistance.
  • the positive detection resistor or negative detection resistance in the same resistance range is quantitatively smaller than the system insulation resistance of different vehicles.
  • the diagnostic equipment controls the switch connected to any one of the positive detection resistor and the negative detection resistor to close each time, and the switch is one of the first switch and the second switch.
  • the switch When the switch is closed, it is equivalent to connecting a detection resistor between the battery and the vehicle ground, and the battery management system of the electric vehicle will measure the resistance of the detection resistor.
  • the diagnostic equipment Based on the communication connection between the diagnostic equipment and the electric vehicle, the diagnostic equipment can read the measured resistance value of the detection resistor fed back by the electric vehicle each time the control switch is closed.
  • the insulation detection module 23 of the battery management system will measure the resistance of the battery's positive electrode to the ground, that is, measure the resistance of the positive electrode detection resistor Rpi.
  • the resistance value is called the measured resistance value Rpi_read. Therefore, the diagnostic device reads the measured resistance value Rpi_read of the detection resistor Rpi fed back by the electric vehicle.
  • the diagnostic equipment determines the measurement deviation of the electric vehicle for the detection resistor based on the measured resistance value of the detection resistor and the actual resistance value of the detection resistor. In some embodiments, the following formula can be used to calculate the measurement deviation of the positive detection resistor:
  • R pi is the i-th positive detection resistor
  • R pi_read is the measured resistance value corresponding to the i-th positive detection resistor
  • R ni is the i-th negative detection resistor
  • R ni_read is the measured resistance value corresponding to the i-th negative detection resistor
  • the diagnostic equipment uploads the measurement deviation to the server, and the server determines the electric vehicle's The insulation detection function is normal or failed. If the measurement deviation is small, it means that the electric vehicle's resistance to ground measurement is accurate, and the insulation detection function is normal. If the measurement deviation is large, it means that the electric vehicle's resistance to ground measurement is inaccurate, and the insulation detection function fails.
  • the diagnostic device can control the switch connected to the same detection resistor to close, so that the server obtains at least one measurement deviation of the electric vehicle for the detection resistor, based on at least one Measurement deviation can accurately determine whether the insulation detection function of electric vehicles is normal or failed, and avoid diagnostic errors.
  • the diagnostic device can control the switches connected to different detection resistors to close, so that the server obtains the measurement deviations of the electric vehicle for multiple detection resistors. Based on the N detection resistor groups corresponding to N resistance ranges one by one, in multiple diagnoses, the diagnostic system can detect the accuracy of the electric vehicle's resistance measurement in each resistance range, making the diagnosis results of the insulation detection function more precise.
  • the diagnostic device after the diagnostic device sequentially controls the first switch and the second switch corresponding to one of the N detection resistor groups to close, the diagnostic device then sequentially controls the next detection resistor group among the N detection resistor groups. The corresponding first switch and second switch are closed.
  • N is 4.
  • the first detection resistor group includes the positive detection resistor Rp1 and the negative detection resistor Rn1.
  • the second detection resistor group includes the positive detection resistor Rp2 and the negative detection resistor Rn2.
  • the third detection resistor group includes Positive detection resistor Rp3, negative detection resistor Rn3, the fourth detection resistor group includes positive detection resistor Rp4, negative detection resistor Rn4.
  • two measured resistance values are obtained after the diagnostic device sequentially controls Rp1 and Rn1 to close, two measured resistance values are obtained.
  • the diagnostic equipment sequentially controls the first switches corresponding to the N positive detection resistors and the second switches corresponding to the N negative detection resistors to close in turn, resulting in 2N measured resistance values.
  • the diagnostic equipment uploads the measurement deviations corresponding to the N detection resistor groups (2N measurement deviations) to the server.
  • the server determines whether the insulation detection function of the electric vehicle is normal or failed based on the measurement deviations corresponding to the N detection resistor groups. For example, if there is a measurement deviation greater than or equal to the deviation threshold among the measurement deviations corresponding to the N detection resistor groups, it is determined that the insulation detection function of the electric vehicle has failed; if the measurement deviations corresponding to the N detection resistor groups are all within a certain range, then Make sure the insulation detection function of the electric vehicle is normal.
  • the diagnostic device controls the switches corresponding to the detection resistors in the N detection resistor groups to close, that is, the 2N detection resistors are individually turned on to obtain 2N measurement deviations, and the server performs diagnosis based on the 2N measurement deviations. For example, if there is a measurement deviation greater than or equal to the deviation threshold among the measurement deviations corresponding to the N detection resistor groups, it is determined that the insulation detection function of the electric vehicle has failed; if the measurement deviations corresponding to the N detection resistor groups are all within a certain range, then Make sure the insulation detection function of the electric vehicle is normal.
  • the diagnostic system can detect the measurement accuracy of the electric vehicle's resistance in each resistance range during each diagnosis, making the diagnosis results of the insulation detection function more accurate.
  • the server detects that among the measurement deviations corresponding to the N detection resistor groups for the first preset number of consecutive times, a target measurement deviation is greater than or equal to the deviation threshold, it is determined that the insulation detection function of the electric vehicle has failed.
  • the target measurement deviation is any one of the measurement deviations corresponding to the N detection resistor groups.
  • the first preset number of times can be set by those skilled in the art according to actual conditions.
  • the first preset number of times is 3 times.
  • the diagnostic system performs multiple diagnoses on the electric vehicle. Each diagnosis obtains the measured resistance values of 2N detection resistors fed back by the electric vehicle, and obtains 2N measurement deviations. If a target measurement deviation greater than or equal to the deviation threshold is detected three times in a row among the 2N measurement deviations, it means that the electric vehicle’s measurement value of the detection resistor is inaccurate and the electric vehicle cannot accurately collect the resistance value of the ground resistance, thus affecting the The insulation detection function makes the insulation detection function invalid.
  • the server can be communicatively connected with multiple diagnostic devices, and the multiple diagnostic devices send measurement data to the server respectively, and the server determines the diagnostic results. Therefore, electric vehicles can be diagnosed multiple times on different diagnostic equipment, regardless of the location of the diagnostic equipment. If the server detects that the electric vehicle's external resistance measurement is inaccurate for the first preset number of times, it will determine the insulation of the electric vehicle. The detection function is disabled. Through the constraint of the first preset number of consecutive times, the probability of misdiagnosis can be reduced and the reliability of diagnosis can be improved.
  • the diagnostic device sequentially controls the first switch and the second switch corresponding to one of the N detection resistor groups to close, the diagnostic device then sequentially controls the next detection resistor group among the N detection resistor groups. The corresponding first switch and second switch are closed.
  • the diagnostic device obtains at least one measurement deviation corresponding to a detection resistance group, it uploads at least one measurement deviation corresponding to the detection resistance group to the server. Therefore, the server determines the electric vehicle based on at least one measurement deviation corresponding to the detection resistance group.
  • the insulation detection function is normal or failed.
  • the diagnostic device sequentially controls the first switch corresponding to the positive detection resistor Rpi to close and the second switch corresponding to the negative detection resistor Rni to close. separate Two measurement resistors are obtained, and then two measurement deviations are obtained based on the actual resistance values of Rpi and Rni.
  • the diagnostic device obtains at least one of the measurement deviation corresponding to the positive detection resistor Rpi or the measurement deviation corresponding to the negative detection resistor Rni, it uploads at least one measurement deviation to the server. For example, the diagnostic device obtains the measurement deviation corresponding to the positive detection resistor Rpi.
  • the diagnostic device obtains the measurement deviation corresponding to the positive detection resistor Rpi and the measurement deviation corresponding to the negative detection resistor Rni and uploads the two measurement deviations to the server. server. Therefore, when the diagnostic equipment collects the measured resistance value of the electric vehicle for the detection resistor, the server can determine in real time whether the electric vehicle's measurement of the detection resistor is abnormal, thereby determining whether the insulation detection function is normal or failed. For example, if the measurement deviation is greater than the deviation threshold, the measurement is abnormal and the insulation detection function fails; if the measurement deviation is less than or equal to the deviation threshold, the measurement is accurate and the insulation detection function is normal.
  • the server after collecting and measuring the resistance value of the detection resistor in each detection resistor group, it is uploaded in real time, so that the server can confirm in real time whether the measurement of the detection resistor is abnormal, thereby determining in real time whether the insulation detection function is normal or failed.
  • the insulation resistance of the battery's positive electrode to ground and the insulation resistance of the negative electrode to ground are infinite to achieve the insulation protection effect.
  • the positive electrode detection resistance and the negative electrode detection resistance are both smaller than the insulation resistance of the battery's positive electrode to ground and the insulation resistance of the negative electrode to ground. Therefore, when the first switch or the second switch corresponding to the detection resistor group with the smallest resistance range is closed, it is equivalent to connecting a smaller resistance (less than 100 ⁇ /V) between the battery and the vehicle ground, so that the electric vehicle is connected to the ground. Not insulated, leakage occurs.
  • the insulation detection module 23 of the battery management system will detect the resistance of the battery to ground. If it is found that the resistance is small and the insulation is poor, and there is a risk of electric leakage and electric shock, the battery management system will report an alarm message and promptly cut off the power supply of the battery. output terminal.
  • the diagnostic device sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, and then reads the feedback information of the electric vehicle; the diagnostic device determines the insulation detection of the electric vehicle based on the feedback information. Functional or malfunctioning.
  • the diagnostic device controls the first switch corresponding to Rp1 to close, so that the positive terminal of the electric vehicle battery is short-circuited.
  • the feedback information sent by the electric vehicle includes insulation alarm information, which reminds the user that a short-circuit leakage accident has occurred; when the insulation detection function fails, the feedback information sent by the electric vehicle does not include insulation alarm information. Unable to alert user.
  • the diagnostic equipment controls the second switch corresponding to Rn1 to close, causing the negative terminal of the battery of the electric vehicle to be short-circuited.
  • the feedback information sent by the electric vehicle includes insulation alarm information to remind the user of a short-circuit leakage accident; when the insulation detection function fails, the feedback information sent by the electric vehicle does not include the insulation alarm information and cannot Alert users.
  • the diagnostic device can read the feedback information of the electric vehicle.
  • the diagnostic equipment sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, two feedback messages can be read. If both feedback messages include alarm information, it means that the electric vehicle is faulty.
  • the insulation detection function is normal; if at least one of the two feedback messages does not include alarm information, it means that the insulation detection function of the electric vehicle fails.
  • the diagnostic equipment can accurately monitor whether the insulation detection function of the electric vehicle has normal alarms, and promptly detect the failure of the insulation detection function due to communication failures.
  • the diagnostic device uploads at least one feedback information to the server, and the server determines that the insulation monitoring function of the electric vehicle is normal or failed based on the at least one feedback information.
  • the diagnostic device can read the feedback information of the electric vehicle.
  • the diagnostic equipment sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, two pieces of feedback information can be read.
  • the diagnostic device uploads at least one feedback information to the server, for example, one feedback information corresponding to the positive electrode, one feedback information corresponding to the negative electrode, or two feedback information. Therefore, the server can determine whether the insulation detection function of the electric vehicle is normal or failed based on at least one piece of feedback information. For example, when the server receives two feedback messages, if both feedback messages include warning information, it means that the insulation detection function of the electric vehicle is normal; if at least one of the two feedback messages does not include warning information, it means that The insulation detection function of electric vehicles fails.
  • the diagnostic device uploads at least one piece of feedback information to the server, and the server determines whether the insulation monitoring function of the electric vehicle is normal or invalid. Therefore, after multiple diagnoses, the server can save the results of multiple diagnoses and analyze the diagnostic structure. the trend of.
  • the server can communicate with multiple diagnostic devices, and the multiple diagnostic devices send feedback information to the server respectively, and the server determines the diagnostic results. Therefore, the electric vehicle can be diagnosed multiple times on different diagnostic devices without being affected by the diagnosis.
  • the location constraints of the equipment can also trace historical diagnosis results, making diagnosis more accurate and reliable.
  • the feedback information detected by electric vehicles on different diagnostic equipment is stored and archived through the server.
  • the server can present the diagnosis results to the user through the diagnostic device screen, printing device, mobile APP, management background, etc. If it is determined that the vehicle insulation detection function has failed, it is recommended that the user go to the repair shop as soon as possible for troubleshooting and repair.
  • the server detects an alarm anomaly in at least one piece of feedback information for a second preset number of consecutive times, it is determined that the insulation detection function of the electric vehicle has failed.
  • the alarm abnormality means that when the first switch or the second switch corresponding to the detection resistor group with the smallest resistance range is closed, the feedback information of the electric vehicle should originally include alarm information, but does not include the alarm information.
  • the second preset number of times can be set by those skilled in the art according to actual conditions.
  • the second preset number of times is 3 times.
  • the diagnostic system performs multiple diagnoses on the electric vehicle, and obtains feedback information sent by the electric vehicle for each diagnosis. If there are alarm abnormalities in the feedback information for three consecutive diagnoses, it means that the electric vehicle did not accurately report the alarm in the case of short circuit leakage, a reporting failure occurred, and the insulation detection function failed.
  • the server detects that the electric vehicle reports a fault for the second preset number of consecutive times, it is determined that the insulation detection function of the electric vehicle has failed.
  • the probability of misdiagnosis can be reduced and the reliability of diagnosis can be improved.
  • the diagnostic device further includes a voltmeter, and the voltmeter is connected between the positive terminal and the negative terminal of the DC bus.
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle
  • the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle, so that the voltmeter can measure the voltage of the battery.
  • the diagnostic device After the voltmeter measures the voltage of the battery, the diagnostic device reads the voltage of the electric vehicle battery measured by the voltmeter. If the voltage is the normal output voltage of the battery, it prompts the control to close the switch to perform diagnostic work. It can be understood that if the voltage is the normal output voltage of the battery, it means that the battery of the electric vehicle is properly connected to the diagnostic equipment, and the diagnostic work can be started. Therefore, the prompt control closes the switch to perform the diagnostic work.
  • the voltage of the electric vehicle battery is measured with a voltmeter, and the shutdown switch is controlled to perform diagnostic work while ensuring that the battery of the electric vehicle is properly connected to the diagnostic device, making the diagnostic device more accurate and safer.
  • the diagnostic device sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, if the diagnostic device respectively reads that the voltage measured by the voltmeter is 0, it is determined that the electric vehicle The battery positive diagnosis result is normal.
  • the resistance of the battery positive electrode of the electric vehicle to the ground is the positive detection resistor with the smallest resistance value, that is, the battery positive electrode is not insulated from the ground, and a positive electrode fault occurs. Risk of leakage.
  • the cut-off protection should be triggered, that is, the battery's power supply output end should be cut off in a timely manner so that the battery's output voltage is 0.
  • the insulation detection module of the battery management system can detect the positive electrode insulation fault in time. The protection is triggered, therefore, it is determined that the positive battery diagnosis result of the electric vehicle is normal.
  • the resistance of the negative electrode of the electric vehicle battery to the ground is the negative electrode detection resistor with the smallest resistance value, that is, the negative electrode of the battery is not insulated from the ground, and the risk of negative electrode leakage occurs.
  • the cut-off protection should be triggered, that is, the battery's power supply output end should be cut off in time so that the battery's output voltage is 0.
  • the second switch corresponding to the detection resistor group with the smallest resistance range is closed, if the diagnostic equipment reads that the voltage measured by the voltmeter is 0, it means that the insulation detection module of the battery management system can detect the negative electrode insulation fault in time. The protection is triggered, therefore, it is determined that the negative battery diagnosis result of the electric vehicle is normal.
  • a voltmeter is used to monitor whether the battery management system can trigger the cut-off protection in time after the risk of leakage occurs in the battery of the electric vehicle, and it can be accurately determined whether the diagnosis result of the positive or negative electrode of the battery of the electric vehicle is normal.
  • the failure diagnosis system also includes a vehicle communication interface (VCI).
  • VCI vehicle communication interface
  • the vehicle communication interface device is used to communicate between the diagnostic equipment and the electric vehicle.
  • Car communication interface equipment is installed around the steering wheel of the car.
  • One port of the automotive communication interface device can be used to connect to the OBD interface of the car, and the other port can be used to connect to the OBD interface of the diagnostic device.
  • the failure diagnosis system for the insulation detection function of electric vehicles includes communication-connected diagnostic equipment and a server.
  • the diagnostic equipment includes a DC bus, N detection resistor groups and equipment grounds, and N detection resistors.
  • the resistance groups correspond to N resistance areas one by one.
  • Each detection resistor group includes a positive detection resistor and a negative detection resistor.
  • the positive detection resistor is connected to the positive terminal of the DC bus and the device ground through the first switch.
  • the negative detection resistor is connected through the first switch.
  • the second switch connects the negative terminal of the DC bus to the equipment ground.
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle
  • the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle
  • the diagnostic equipment is connected to the electric vehicle for communication.
  • the diagnostic equipment controls the switch connected to any one of the positive detection resistor and the negative detection resistor to close each time, and the switch is one of the first switch and the second switch.
  • the diagnostic equipment reads the measured resistance value of the detection resistor fed back by the electric vehicle.
  • the diagnostic equipment determines the measurement deviation of the electric vehicle for the detection resistor based on the measured resistance value of the detection resistor and the actual resistance value of the detection resistor.
  • the diagnostic device uploads the measurement deviation to the server, and the server determines whether the insulation detection function of the electric vehicle is normal or failed based on at least one measurement deviation of the electric vehicle for the detection resistor.
  • the diagnostic equipment can accurately detect the measurement deviation of the electric vehicle's external resistance. Based on the measurement deviation, the server can determine whether the electric vehicle's detection of the external resistance is accurate. If the measurement is accurate, the insulation detection function is normal. If the measurement is not accurate, the insulation detection function is normal. If it is accurate, the insulation detection function will fail. Based on the fact that N detection resistor groups correspond to N resistance ranges one by one, in multiple diagnoses, the diagnostic system can detect the measurement accuracy of the electric vehicle's resistance in each resistance range, making the diagnosis results more accurate.
  • the diagnostic device includes: a DC bus, N detection resistor groups, a device ground and a processor, and a communication module.
  • the processor can be a central processing unit (CPU), a network processor (network processor, NP), a hardware chip or any combination thereof.
  • the communication module may include a communication interface and a network antenna.
  • the communication interface is used for wired communication connection with the electric vehicle.
  • the network antenna can be connected for wireless communication with the server.
  • N detection resistor groups correspond to N resistance ranges one by one.
  • Each detection resistor group includes a positive detection resistor and a negative detection resistor.
  • the positive detection resistor is connected to the positive terminal of the DC bus and the device ground through the first switch.
  • the negative detection resistor The resistor connects the negative terminal of the DC bus to equipment ground through a second switch.
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle, and the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle.
  • the equipment ground refers to the equipment shell that can be touched by users.
  • N is an integer greater than or equal to 1.
  • N can be 4, then there are 4 detection resistor groups with different resistance ranges, including 4 positive detection resistors with different resistance values and 4 negative detection resistors with different resistance values.
  • Figure 3 simplifies the diagram showing that the positive detection resistor Rpi and the corresponding first switch Kpi in any detection resistor group are connected between the positive terminal of the DC bus and the device ground, and the negative detection resistor Rni and the corresponding second switch Kni are connected to the DC bus. Between the negative terminal of the bus and device ground. It can be understood that in FIG. 3, other detection resistor groups are not shown.
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle, and the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle.
  • the first switch Kpi is closed, it is equivalent to connecting the positive terminal of the battery and the device.
  • a positive detection resistor Rpi is connected between the ground.
  • the second switch Kni is closed, it is equivalent to connecting a negative detection resistor Rni between the negative electrode of the battery and the equipment ground.
  • the equipment ground is the ground terminal.
  • the insulation resistance of the battery's positive electrode to the ground and the insulation resistance of the negative electrode to the ground are infinite to achieve the insulation protection effect.
  • Both the positive detection resistance and the negative detection resistance are smaller than the insulation resistance of the battery's positive electrode to ground and the insulation resistance of the negative electrode to ground. Therefore, when any switch is closed, it is equivalent to connecting a detection resistor between the battery and the vehicle ground, so that the battery is not insulated from the ground.
  • the insulation detection module 23 of the battery management system will detect the resistance of the battery to ground. If it is found that the resistance is small and the insulation is poor, and there is a risk of electric leakage and electric shock, the battery management system will report an alarm message and promptly cut off the power supply of the battery. output terminal.
  • the vehicle insulation detection function will trigger a serious fault when the quantitative value of the system insulation resistance measured is lower than 100 ⁇ /V.
  • the system insulation resistance A slight alarm will be triggered when the quantitative value is between 100 ⁇ /V and 500 ⁇ /V.
  • the quantitative value of the system insulation resistance refers to the smaller value of the insulation resistance between the positive electrode and the ground or the negative electrode and the ground. It is understandable that for vehicles with different operating voltages, the quantitative values of system insulation resistance are also different.
  • N detection resistor groups with different resistance ranges are set up (taking N as 4 as an example), covering 4 resistance ranges. For example, select one resistance value from each of the four resistance ranges: 0 ⁇ /V ⁇ 100 ⁇ /V, 100 ⁇ /V ⁇ 500 ⁇ /V, 500 ⁇ /V ⁇ 2000 ⁇ /V, and greater than 2000 ⁇ /V as the positive detection resistor and negative detection resistor. The resistance of the resistor.
  • the resistance values of the positive detection resistor and the negative detection resistor can be set by referring to Table 1.
  • the resistance values of the four positive detection resistors and the four negative detection resistors are distributed between 0 ⁇ /V ⁇ 100 ⁇ /V, 100 ⁇ /V ⁇ 500 ⁇ /V, and 500 ⁇ There are four resistance ranges: /V ⁇ 2000 ⁇ /V and greater than 2000 ⁇ /V. For each resistance range, vehicles with different operating voltages have different quantitative values of system insulation resistance.
  • the positive detection resistor or negative detection resistance in the same resistance range is quantitatively smaller than the system insulation resistance of different vehicles.
  • the processor controls the switch connected to either one of the positive detection resistor and the negative detection resistor to close each time, and the switch is one of the first switch and the second switch.
  • the switch When the switch is closed, it is equivalent to connecting a detection resistor between the battery and the vehicle ground, and the battery management system of the electric vehicle will measure the resistance of the detection resistor.
  • the communication module Based on the communication connection between the diagnostic equipment and the electric vehicle through the communication module, each time the processor controls the switch to close, the communication module can read the measured resistance value of the detection resistor fed back by the electric vehicle.
  • the insulation detection module 23 of the battery management system will measure the resistance of the battery's positive electrode to the ground, that is, measure the resistance of the positive electrode detection resistor Rpi.
  • the resistance value is called the measured resistance value Rpi_read. Therefore, the communication module reads the measured resistance value Rpi_read of the detection resistor Rpi fed back by the electric vehicle.
  • the processor determines the measurement deviation of the electric vehicle for the detection resistor based on the measured resistance value of the detection resistor and the actual resistance value of the detection resistor. In some embodiments, the following formula can be used to calculate the measurement deviation of the positive detection resistor:
  • R pi is the i-th positive detection resistor
  • R pi_read is the measured resistance value corresponding to the i-th positive detection resistor
  • R ni is the i-th negative detection resistor
  • R ni_read is the measured resistance value corresponding to the i-th negative detection resistor
  • the processor determines whether the insulation detection function of the electric vehicle is normal or failed based on the measurement deviation of the electric vehicle against the detection resistance. If the measurement deviation is small, it means that the electric vehicle's resistance to ground measurement is accurate, and the insulation detection function is normal. If the measurement deviation is large, it means that the electric vehicle's resistance to ground measurement is inaccurate, and the insulation detection function fails.
  • the processor can control the switch connected to the same detection resistor to close, so that the processor obtains at least one measurement deviation of the electric vehicle for the detection resistor, based on at least A measurement deviation can accurately determine whether the insulation detection function of an electric vehicle is normal or failed, avoiding diagnostic errors.
  • the processor can control the switches connected to different detection resistors to close, so that the processor obtains the measurement deviation of the electric vehicle for multiple detection resistors.
  • the diagnostic equipment can detect the accuracy of the electric vehicle's resistance measurement in each resistance range, making the diagnosis results of the insulation detection function more precise.
  • the diagnostic device after the processor sequentially controls the first switch and the second switch corresponding to one of the N detection resistor groups to close, the diagnostic device then sequentially controls the next detection resistor group among the N detection resistor groups. The corresponding first switch and second switch are closed.
  • N is 4.
  • the first detection resistor group includes the positive detection resistor Rp1 and the negative detection resistor Rn1.
  • the second detection resistor group includes the positive detection resistor Rp2 and the negative detection resistor Rn2.
  • the third detection resistor group includes Positive detection resistor Rp3, negative detection resistor Rn3, the fourth detection resistor group includes positive detection resistor Rp4, negative detection resistor Rn4.
  • two measured resistance values are obtained after the diagnostic device sequentially controls Rp1 and Rn1 to close, two measured resistance values are obtained.
  • the processor sequentially controls the first switch corresponding to the N positive detection resistors and the second switch corresponding to the N negative detection resistors to close in turn, thereby obtaining 2N measured resistance values.
  • the processor determines whether the insulation detection function of the electric vehicle is normal or failed based on the measurement deviations corresponding to the N detection resistor groups. For example, if there is a measurement deviation greater than or equal to the deviation threshold among the measurement deviations corresponding to the N detection resistor groups, it is determined that the insulation detection function of the electric vehicle has failed; if the measurement deviations corresponding to the N detection resistor groups are all within a certain range, then Make sure the insulation detection function of the electric vehicle is normal.
  • the processor controls the switches corresponding to the detection resistors in the N detection resistor groups to close, that is, the 2N detection resistors are individually turned on to obtain 2N measurement deviations, and diagnosis is performed based on these 2N measurement deviations. For example, if there is a measurement deviation greater than or equal to the deviation threshold among the measurement deviations corresponding to the N detection resistor groups, it is determined that the insulation detection function of the electric vehicle has failed; if the measurement deviations corresponding to the N detection resistor groups are all within a certain range, then Make sure the insulation detection function of the electric vehicle is normal.
  • the diagnostic equipment can detect the measurement accuracy of the electric vehicle's resistance in each resistance value interval during each diagnosis, making the diagnosis results of the insulation detection function more accurate.
  • the processor detects for the first preset number of consecutive times that a target measurement deviation among the measurement deviations corresponding to the N detection resistor groups is greater than or equal to the deviation threshold, it is determined that the insulation detection function of the electric vehicle has failed.
  • the target measurement deviation is any one of the measurement deviations corresponding to the N detection resistor groups.
  • the first preset number of times can be set by those skilled in the art according to actual conditions.
  • the first preset number of times is 3 times.
  • the diagnostic equipment performs multiple diagnoses on the electric vehicle. Each diagnosis obtains the measured resistance values of 2N detection resistors fed back by the electric vehicle, and obtains 2N measurement deviations. If a target measurement deviation greater than or equal to the deviation threshold is detected three times in a row among the 2N measurement deviations, it means that the electric vehicle’s measurement value of the detection resistor is inaccurate and the electric vehicle cannot accurately collect the resistance value of the ground resistance, thus affecting the The insulation detection function makes the insulation detection function invalid.
  • the processor detects that the external resistance measurement of the electric vehicle is inaccurate for the first preset number of times, it is determined that the insulation detection function of the electric vehicle has failed.
  • the probability of misdiagnosis can be reduced and the reliability of diagnosis can be improved.
  • the processor after the processor sequentially controls the first switch and the second switch corresponding to one of the N detection resistor groups to close, the processor then sequentially controls the next detection resistor in the N detection resistor groups. The first switch and the second switch corresponding to the group are closed.
  • the processor Each time the processor obtains at least one measurement deviation corresponding to a detection resistor group, it determines whether the insulation detection function of the electric vehicle is normal or failed based on at least one measurement deviation corresponding to the detection resistor group.
  • the detection resistor group includes a positive detection resistor Rpi and a negative detection resistor Rni.
  • the processor sequentially controls the first switch corresponding to the positive detection resistor Rpi to close and the second switch corresponding to the negative detection resistor Rni to close. Get respectively Two measurement resistors, and then based on the actual resistance values of Rpi and Rni, two measurement deviations are obtained respectively.
  • the processor determines the corresponding measurement deviation when it obtains at least one of the measurement deviation corresponding to the positive detection resistor Rpi or the measurement deviation corresponding to the negative detection resistor Rni. For example, the processor obtains the measurement deviation corresponding to the positive detection resistor Rpi or the negative detection resistor.
  • the measurement deviation corresponding to Rni or after the processor obtains the measurement deviation corresponding to the positive detection resistor Rpi and the measurement deviation corresponding to the negative detection resistor Rni, the processor can determine in real time whether the electric vehicle's measurement of the detection resistor is abnormal, thereby, Determine whether the insulation detection function is normal or failed. For example, if the measurement deviation is greater than the deviation threshold, the measurement is abnormal and the insulation detection function fails; if the measurement deviation is less than or equal to the deviation threshold, the measurement is accurate and the insulation detection function is normal.
  • the insulation resistance of the battery's positive electrode to ground and the insulation resistance of the negative electrode to ground are infinite to achieve the insulation protection effect.
  • the positive electrode detection resistance and the negative electrode detection resistance are both smaller than the insulation resistance of the battery's positive electrode to ground and the insulation resistance of the negative electrode to ground. Therefore, when the first switch or the second switch corresponding to the detection resistor group with the smallest resistance range is closed, it is equivalent to connecting a smaller resistance (less than 100 ⁇ /V) between the battery and the vehicle ground, so that the electric vehicle is connected to the ground. Not insulated, leakage occurs.
  • the insulation detection module 23 of the battery management system will detect the resistance of the battery to ground. If it is found that the resistance is small and the insulation is poor, and there is a risk of electric leakage and electric shock, the battery management system will report an alarm message and promptly cut off the power supply of the battery. output terminal.
  • the processor sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, and then reads the feedback information of the electric vehicle; the diagnostic device determines the insulation detection of the electric vehicle based on the feedback information. Functional or malfunctioning.
  • the diagnostic device controls the first switch corresponding to Rp1 to close, so that the positive terminal of the electric vehicle battery is short-circuited.
  • the feedback information sent by the electric vehicle includes insulation alarm information, which reminds the user that a short-circuit leakage accident has occurred; when the insulation detection function fails, the feedback information sent by the electric vehicle does not include insulation alarm information. Unable to alert user.
  • the diagnostic equipment controls the second switch corresponding to Rn1 to close, causing the negative terminal of the battery of the electric vehicle to be short-circuited.
  • the feedback information sent by the electric vehicle includes insulation alarm information to remind the user of a short-circuit leakage accident; when the insulation detection function fails, the feedback information sent by the electric vehicle does not include the insulation alarm information and cannot Alert users.
  • the communication module can read the feedback information of the electric vehicle. After the processor sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, the communication module can read two feedback messages. If both feedback messages include alarm information, it means that the electric motor The insulation detection function of the car is normal; if at least one of the two feedback messages does not include alarm information, it means that the insulation detection function of the electric vehicle is invalid.
  • the diagnostic equipment can accurately monitor whether the insulation detection function of the electric vehicle has normal alarms, and promptly detect the failure of the insulation detection function due to communication failures.
  • the processor detects an alarm anomaly in at least one piece of feedback information for a second preset number of consecutive times, it is determined that the insulation detection function of the electric vehicle has failed.
  • the alarm abnormality means that when the first switch or the second switch corresponding to the detection resistor group with the smallest resistance range is closed, the feedback information of the electric vehicle should originally include alarm information, but does not include the alarm information.
  • the second preset number of times can be set by those skilled in the art according to actual conditions.
  • the second preset number of times is 3 times.
  • the diagnostic equipment performs multiple diagnoses on the electric vehicle, and obtains feedback information sent by the electric vehicle for each diagnosis. If there are alarm abnormalities in the feedback information for three consecutive diagnoses, it means that the electric vehicle did not accurately report the alarm in the case of short circuit leakage, a reporting failure occurred, and the insulation detection function failed.
  • the processor detects that the electric vehicle reports a fault for a second preset number of times, it is determined that the insulation detection function of the electric vehicle has failed.
  • the probability of misdiagnosis can be reduced and the reliability of diagnosis can be improved.
  • the diagnostic device further includes a voltmeter, and the voltmeter is connected between the positive terminal and the negative terminal of the DC bus.
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle
  • the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle, so that the voltmeter can measure the voltage of the battery.
  • the processor After the voltmeter measures the voltage of the battery, the processor reads the voltage of the electric vehicle battery measured by the voltmeter. If the voltage is the normal output voltage of the battery, it prompts the control to close the switch to perform diagnostic work. It can be understood that if the voltage is the normal output voltage of the battery, it means that the battery of the electric vehicle is properly connected to the diagnostic equipment, and the diagnostic work can be started. Therefore, the prompt control closes the switch to perform the diagnostic work.
  • the voltage of the electric vehicle battery is measured with a voltmeter, and the shutdown switch is controlled to perform diagnostic work while ensuring that the battery of the electric vehicle is properly connected to the diagnostic device, making the diagnostic device more accurate and safer.
  • the processor sequentially controls the first switch and the second switch corresponding to the detection resistor group with the smallest resistance range to close, if the processor reads that the voltage measured by the voltmeter is 0, it is determined that the electric vehicle The battery positive diagnosis result is normal.
  • the resistance of the battery positive electrode of the electric vehicle to the ground is the positive detection resistor with the smallest resistance value, that is, the battery positive electrode is not insulated from the ground, and a positive electrode fault occurs. Risk of leakage.
  • the cut-off protection should be triggered, that is, the battery's power supply output end should be cut off in a timely manner so that the battery's output voltage is 0.
  • the processor reads that the voltage measured by the voltmeter is 0, it means that the insulation detection module of the battery management system can detect the positive electrode insulation fault in time. The protection is triggered, therefore, it is determined that the positive battery diagnosis result of the electric vehicle is normal.
  • the resistance of the negative electrode of the electric vehicle battery to the ground is the negative electrode detection resistor with the smallest resistance value, that is, the negative electrode of the battery is not insulated from the ground, and the risk of negative electrode leakage occurs.
  • the cut-off protection should be triggered, that is, the battery's power supply output end should be cut off in time so that the battery's output voltage is 0.
  • the processor reads that the voltage measured by the voltmeter is 0, it means that the insulation detection module of the battery management system can detect the negative electrode insulation fault in time. The protection is triggered, therefore, it is determined that the negative battery diagnosis result of the electric vehicle is normal.
  • the diagnostic equipment uses a voltmeter to monitor whether the battery management system can trigger the cut-off protection in time after the risk of leakage occurs in the battery of the electric vehicle, and can accurately determine whether the diagnosis result of the positive or negative electrode of the battery of the electric vehicle is normal.
  • the diagnostic equipment can accurately detect the measurement deviation of the electric vehicle's external resistance. Based on the measurement deviation, the server can determine whether the electric vehicle's detection of the external resistance is accurate. If the measurement is accurate, the insulation detection function is normal. If the measurement is inaccurate , the insulation detection function fails. Based on the N detection resistor groups corresponding to N resistance ranges one by one, in multiple diagnoses, the diagnostic equipment can detect the measurement accuracy of the electric vehicle's resistance in each resistance range, making the diagnosis results more accurate.
  • a diagnostic device which includes a DC bus, N detection resistor groups, a device ground, a processor, and a communication module.
  • the processor can be a central processing unit (CPU), a network processor (network processor, NP), a hardware chip or any combination thereof.
  • the communication module may include a communication interface and a network antenna. The communication interface is used for wired communication connection with the electric vehicle. The network antenna can be connected for wireless communication with the server.
  • N detection resistor groups correspond to N resistance ranges one by one.
  • Each detection resistor group includes a positive detection resistor and a negative detection resistor.
  • the positive detection resistor is connected to the positive terminal of the DC bus and the device ground through the first switch.
  • the negative detection resistor The resistor connects the negative terminal of the DC bus to equipment ground through a second switch.
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle, and the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle.
  • the equipment ground refers to the equipment shell that can be touched by users.
  • N is an integer greater than or equal to 1.
  • N can be 4, then there are 4 detection resistor groups with different resistance ranges, including 4 positive detection resistors with different resistance values and 4 negative detection resistors with different resistance values. .
  • the positive terminal of the DC bus is connected to the positive terminal of the battery of the electric vehicle, and the negative terminal of the DC bus is connected to the negative terminal of the battery of the electric vehicle.
  • the first switch Kpi is closed, it is equivalent to connecting the positive terminal of the battery and the device.
  • a positive detection resistor Rpi is connected between the ground.
  • the second switch Kni is closed, it is equivalent to connecting a negative detection resistor Rni between the negative electrode of the battery and the equipment ground.
  • the equipment ground is the ground terminal.
  • the insulation resistance of the battery's positive electrode to the ground and the insulation resistance of the negative electrode to the ground are infinite to achieve the insulation protection effect.
  • Both the positive detection resistance and the negative detection resistance are smaller than the insulation resistance of the battery's positive electrode to ground and the insulation resistance of the negative electrode to ground. Therefore, when any switch is closed, it is equivalent to connecting a detection resistor between the battery and the vehicle ground, so that the battery is not insulated from the ground.
  • the insulation detection module 23 of the battery management system will detect the resistance of the battery to ground. If it is found that the resistance is small and the insulation is poor, and there is a risk of electric leakage and electric shock, the battery management system will report an alarm message and promptly cut off the power supply of the battery. output terminal.
  • the vehicle insulation detection function will trigger a serious fault when the quantitative value of the system insulation resistance measured is lower than 100 ⁇ /V.
  • the system insulation resistance A slight alarm will be triggered when the quantitative value is between 100 ⁇ /V and 500 ⁇ /V.
  • the quantitative value of the system insulation resistance refers to the smaller value of the insulation resistance between the positive electrode and the ground or the negative electrode and the ground. It is understandable that for vehicles with different operating voltages, the quantitative values of system insulation resistance are also different.
  • N detection resistor groups with different resistance ranges are set up (taking N as 4 as an example), covering 4 resistance ranges. For example, select one resistance value from each of the four resistance ranges: 0 ⁇ /V ⁇ 100 ⁇ /V, 100 ⁇ /V ⁇ 500 ⁇ /V, 500 ⁇ /V ⁇ 2000 ⁇ /V, and greater than 2000 ⁇ /V as the positive detection resistor and negative detection resistor. The resistance of the resistor.
  • the resistance values of the positive detection resistor and the negative detection resistor can be set by referring to Table 1.
  • the resistance values of the four positive detection resistors and the four negative detection resistors are distributed between 0 ⁇ /V ⁇ 100 ⁇ /V, 100 ⁇ /V ⁇ 500 ⁇ /V, and 500 ⁇ There are four resistance ranges: /V ⁇ 2000 ⁇ /V and greater than 2000 ⁇ /V. For each resistance range, vehicles with different operating voltages have different quantitative values of system insulation resistance.
  • the positive detection resistor or negative detection resistance in the same resistance range is quantitatively smaller than the system insulation resistance of different vehicles.
  • the diagnostic equipment controls the switch connected to any one of the positive detection resistor and the negative detection resistor to close each time, and the switch is one of the first switch and the second switch.
  • the switch When the switch is closed, it is equivalent to connecting a detection resistor between the battery and the vehicle ground, and the battery management system of the electric vehicle will measure the resistance of the detection resistor.
  • the diagnostic equipment Based on the communication connection between the diagnostic equipment and the electric vehicle, the diagnostic equipment controls the After the control switch is closed, the communication module can read the measured resistance value of the detection resistor fed back by the electric vehicle.
  • the insulation detection module 23 of the battery management system will measure the resistance of the battery's positive electrode to the ground, that is, measure the resistance of the positive electrode detection resistor Rpi.
  • the resistance value is called the measured resistance value Rpi_read. Therefore, the communication module reads the measured resistance value Rpi_read of the detection resistor Rpi fed back by the electric vehicle.
  • the diagnostic equipment determines the measurement deviation of the electric vehicle for the detection resistor based on the measured resistance value of the detection resistor and the actual resistance value of the detection resistor. In some embodiments, the following formula can be used to calculate the measurement deviation of the positive detection resistor:
  • R pi is the i-th positive detection resistor
  • R pi_read is the measured resistance value corresponding to the i-th positive detection resistor
  • R ni is the i-th negative detection resistor
  • R ni_read is the measured resistance value corresponding to the i-th negative detection resistor
  • the communication module of the diagnostic equipment uploads the measurement deviation to the server.
  • the server determines whether the insulation detection function of the electric vehicle is normal or failed based on the measurement deviation of the electric vehicle for the detection resistance. If the measurement deviation is small, it means that the electric vehicle's resistance to ground measurement is accurate, and the insulation detection function is normal. If the measurement deviation is large, it means that the electric vehicle's resistance to ground measurement is inaccurate, and the insulation detection function fails.
  • the diagnostic device can control the switch connected to the same detection resistor to close, so that the server obtains at least one measurement deviation of the electric vehicle for the detection resistor, based on at least one Measurement deviation can accurately determine whether the insulation detection function of electric vehicles is normal or failed, and avoid diagnostic errors.
  • the diagnostic device can control the switches connected to different detection resistors to close, so that the server obtains the measurement deviations of the electric vehicle for multiple detection resistors. Based on the N detection resistor groups corresponding to N resistance ranges one-to-one, in multiple diagnoses, the measurement accuracy of the electric vehicle's resistance in each resistance range can be detected, making the diagnosis results of the insulation detection function more accurate. .
  • Some embodiments of the present application also provide a charging pile, including the diagnostic device in any of the above embodiments.
  • the structure and function of the diagnostic equipment are the same as those in some of the above embodiments, and will not be repeated here.
  • the charging pile Before or after charging the electric vehicle, the charging pile can regularly diagnose whether the insulation detection function is effective, and promptly detect the failure of the insulation detection function, which improves convenience and timeliness.

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Abstract

一种电动汽车绝缘检测功能的失效诊断系统、诊断设备及充电桩，该系统包括通信连接的诊断设备和服务器，其中，诊断设备包括直流总线、N个检测电阻群和设备地，N个检测电阻群一一对应于N个阻值区间，各正极检测电阻分别通过第一开关连接直流总线的正极端和设备地，各负极检测电阻分别通过第二开关连接直流总线的负极端和设备地。该诊断系统，能够确定电动汽车对外界电阻的检测是否准确，进而确定绝缘检测功能正常或失效。基于N个检测电阻群一一对应于N个阻值区间，从而，在多次诊断中，诊断系统能够检测到电动汽车对各个阻值区间的电阻的测量准确性，使得诊断结果更加准确。

Description

电动汽车绝缘检测功能的失效诊断系统、方法及设备
本申请要求于2022年5月20日提交中国专利局、申请号为202210554676.X、申请名称为“电动汽车绝缘检测功能的失效诊断系统、方法及设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请实施例涉及电动汽车技术领域，尤其涉及一种电动汽车绝缘检测功能的失效诊断系统、方法及设备。
背景技术
电动汽车采用电能可以解决传统油车带来的能源消耗及温室气体排放等问题，实现节能减排，环保可持续发展。为了满足电动汽车需要的驱动功率(P＝UI)，电动汽车一般采用高压平台设计，以减小工作电流，降低发热和损耗等问题。目前大多数乘用车车型工作电压为400V，已有高端车型推出800V工作电压，部分大型重型电动车辆的工作电压已达到1000V以上。
在如此高电压的系统下，电动汽车的动力电池与外部环境之间的绝缘性非常重要。如果电动汽车的动力电池的绝缘性较差，对使用者的人身安全构成很大威胁。目前，电动汽车具有绝缘检测功能，即主要依靠电池自带的电池管理系统(BATTERY MANAGEMENT SYSTEM,BMS)检测电池正极对地和负极对地的绝缘性。然而，如果绝缘检测功能失效，可能对驾乘人员造成致命的触电风险。
发明内容
本申请实施例主要解决的技术问题是提供一种电动汽车绝缘检测功能的失效诊断系统、方法及设备，能够准确诊断出电动汽车的绝缘检测功能是否失效，及时发现功能失效问题，提升安全性。
为解决上述技术问题，第一方面，本申请实施例中提供给了一种电动汽车绝缘检测功能的失效诊断系统，包括通信连接的诊断设备和服务器，所述诊断设备包括直流总线、N个检测电阻群和设备地，N个所述检测电阻群一一对应于N个阻值区间，每个所述检测电阻群包括一个正极检测电阻和一个负极检测电阻，所述正极检测电阻通过第一开关连接所述直流总线的正极端和所述设备地，所述负极检测电阻通过第二开关连接所述直流总线的负极端和所述设备地，其中，N是大于或等于1的整数；所述直流总线的正极端用于连接电动汽车的电池正极，所述直流总线的负极端用于连接所述电动汽车的电池负极，所述诊断设备还用于与所述电动汽车通信连接；所述诊断设备每次控制所述正极检测电阻和所述负极检测电阻中的任一个检测电阻连接的开关闭合，所述开关为所述第一开关和所述第二开关中的一个；
所述诊断设备每次控制所述开关闭合后，读取所述电动汽车反馈的针对所述检测电阻的测量阻值；
所述诊断设备根据所述检测电阻的测量阻值和所述检测电阻的实际阻值，确定所述电动汽车针对所述检测电阻的测量偏差；
所述诊断设备将所述测量偏差上传至所述服务器，所述服务器根据所述电动汽车针对所述检测电阻的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，所述诊断设备依次控制所述N个检测电阻群中的一个检测电阻群对应的所述第一开关和所述第二开关闭合后，所述诊断设备再依次控制所述N个检测电阻群中的下一个检测电阻群对应的所述第一开关和所述第二开关闭合；
所述诊断设备将所述N个检测电阻群对应的测量偏差上传至所述服务器，所述服务器根据所述N个检测电阻群对应的测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，若所述服务器连续第一预设次数检测到所述N个检测电阻群对应的测量偏差中存在目标测量偏差大于或等于偏差阈值，则确定所述电动汽车的绝缘检测功能失效，所述目标测量偏差为所述N个检测电阻群对应的测量偏差中的任意一个。
在一些实施例中，所述诊断设备依次控制所述N个检测电阻群中的一个检测电阻群对应的所述第一开关和所述第二开关闭合后，所述诊断设备再依次控制所述N个检测电阻群中的下一个检测电阻群对应的所述第一开关和所述第二开关闭合；
所述诊断设备每次得到一个检测电阻群对应的至少一个测量偏差后，将所述检测电阻群对应的至少一个测量偏差上传至所述服务器，所述服务器根据所述检测电阻群对应的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，所述诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭 合后，读取所述电动汽车的反馈信息；
所述诊断设备根据所述反馈信息，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，所述诊断设备将至少一个所述反馈信息上传至所述服务器，所述服务器根据至少一个所述反馈信息确定所述电动汽车的绝缘监测功能正常或失效。
在一些实施例中，若所述服务器连续第二预设次数检测到至少一个所述反馈信息中存在告警异常，则确定所述电动汽车的绝缘检测功能失效。
在一些实施例中，所述诊断设备还包括电压表，所述电压表连接于所述直流总线的正极端和负极端之间；
所述诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，若分别读取所述电压表测量到的电压为0，则确定所述电动汽车的绝缘检测功能正常。
在一些实施例中，在所述诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合之前，所述诊断设备读取所述电压表测量到的电压，若所述电压为所述电池的正常输出电压，则提示控制闭合开关以进行诊断工作。
在一些实施例中，所述系统还包括汽车通信接口设备，所述汽车通信接口设备用于通信连接所述诊断设备和所述电动汽车。
为解决上述技术问题，第二方面，本申请实施例中提供给了一种诊断设备，包括直流总线、N个检测电阻群、设备地、处理器和通信模块；
其中，N个所述检测电阻群一一对应于N个阻值区间，每个所述检测电阻群包括一个正极检测电阻和一个负极检测电阻，所述正极检测电阻通过第一开关连接所述直流总线的正极端和所述设备地，所述负极检测电阻通过第二开关连接所述直流总线的负极端和所述设备地，其中，N是大于或等于1的整数；
所述直流总线的正极端用于连接电动汽车的电池正极，所述直流总线的负极端用于连接所述电动汽车的电池负极，所述通信模块用于与所述电动汽车通信连接；
所述处理器每次控制所述正极检测电阻和所述负极检测电阻中的任一个检测电阻连接的开关闭合，所述开关为所述第一开关和所述第二开关中的一个；
在所述处理器每次控制所述开关闭合后，所述通信模块读取所述电动汽车反馈的针对所述检测电阻的测量阻值；
所述处理器根据所述检测电阻的测量阻值和所述检测电阻的实际阻值，确定所述电动汽车针对所述检测电阻的测量偏差；
所述处理器根据所述电动汽车针对所述检测电阻的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，所述处理器依次控制所述N个检测电阻群中的一个检测电阻群对应的所述第一开关和所述第二开关闭合后，所述处理器再依次控制所述N个检测电阻群中的下一个检测电阻群对应的所述第一开关和所述第二开关闭合；
所述处理器根据所述N个检测电阻群对应的测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，若所述处理器连续第一预设次数检测到所述N个检测电阻群对应的测量偏差中存在目标测量偏差大于或等于偏差阈值，则确定所述电动汽车的绝缘检测功能失效，所述目标测量偏差为所述N个检测电阻群对应的测量偏差中的任意一个。
在一些实施例中，所述处理器依次控制所述N个检测电阻群中的一个检测电阻群对应的所述第一开关和所述第二开关闭合后，所述处理器再依次控制所述N个检测电阻群中的下一个检测电阻群对应的所述第一开关和所述第二开关闭合；
所述处理器每次得到一个检测电阻群对应的至少一个测量偏差后，根据所述检测电阻群对应的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，所述处理器依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，读取所述电动汽车的反馈信息；
根据所述反馈信息，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，若所述处理器连续第二预设次数检测到至少一个所述反馈信息中存在告警异常，则确定所述电动汽车的绝缘检测功能失效。
在一些实施例中，所述诊断设备还包括电压表，所述电压表连接于所述直流总线的正极端和负极端之间；
所述处理器依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，若分别读取所 述电压表测量到的电压为0，则确定所述电动汽车的绝缘检测功能正常。
在一些实施例中，在所述处理器依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合之前，所述通信模块读取所述电压表测量到的电压，若所述电压为所述电池的正常输出电压，则所述处理器提示控制闭合开关以进行诊断工作。
为解决上述技术问题，第三方面，本申请实施例中提供给了一种诊断设备，包括直流总线、N个检测电阻群、设备地、处理器和通信模块；
其中，N个所述检测电阻群一一对应于N个阻值区间，每个所述检测电阻群包括一个正极检测电阻和一个负极检测电阻，所述正极检测电阻通过第一开关连接所述直流总线的正极端和所述设备地，所述负极检测电阻通过第二开关连接所述直流总线的负极端和所述设备地，其中，N是大于或等于1的整数；
所述直流总线的正极端用于连接电动汽车的电池正极，所述直流总线的负极端用于连接所述电动汽车的电池负极，所述通信模块用于分别与服务器和所述电动汽车通信连接；
所述处理器每次控制所述正极检测电阻和所述负极检测电阻中的任一个检测电阻连接的开关闭合，所述开关为所述第一开关和所述第二开关中的一个；
在所述处理器每次控制所述开关闭合后，所述通信模块读取所述电动汽车反馈的针对所述检测电阻的测量阻值；
所述处理器根据所述检测电阻的测量阻值和所述检测电阻的实际阻值，确定所述电动汽车针对所述检测电阻的测量偏差；
所述通信模块将所述测量偏差上传至所述服务器，以使所述服务器根据所述电动汽车针对所述检测电阻的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，所述处理器依次控制所述N个检测电阻群中的一个检测电阻群对应的所述第一开关和所述第二开关闭合后，所述处理器再依次控制所述N个检测电阻群中的下一个检测电阻群对应的所述第一开关和所述第二开关闭合；
所述通信模块将所述N个检测电阻群对应的测量偏差上传至所述服务器，以使所述服务器根据所述N个检测电阻群对应的测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，若所述处理器连续第一预设次数检测到所述N个检测电阻群对应的测量偏差中存在目标测量偏差大于或等于偏差阈值，则确定所述电动汽车的绝缘检测功能失效，所述目标测量偏差为所述N个检测电阻群对应的测量偏差中的任意一个。
在一些实施例中，所述处理器依次控制所述N个检测电阻群中的一个检测电阻群对应的所述第一开关和所述第二开关闭合后，所述处理器再依次控制所述N个检测电阻群中的下一个检测电阻群对应的所述第一开关和所述第二开关闭合；
所述处理器每次得到一个检测电阻群对应的至少一个测量偏差后，所述通信模块将所述检测电阻群对应的至少一个测量偏差上传至所述服务器，以使所述服务器根据所述检测电阻群对应的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，所述处理器依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，读取所述电动汽车的反馈信息；
所述处理器根据所述反馈信息，确定所述电动汽车的绝缘检测功能正常或失效。
在一些实施例中，所述通信模块将至少一个所述反馈信息上传至所述服务器，以使所述服务器根据至少一个所述反馈信息确定所述电动汽车的绝缘监测功能正常或失效。
在一些实施例中，若所述服务器连续第二预设次数检测到至少一个所述反馈信息中存在告警异常，则确定所述电动汽车的绝缘检测功能失效。
在一些实施例中，所述诊断设备还包括电压表，所述电压表连接于所述直流总线的正极端和负极端之间；
所述处理器依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，若所述通信模块分别读取所述电压表测量到的电压为0，则所述处理器确定所述电动汽车的绝缘检测功能正常。
在一些实施例中，在所述处理器依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合之前，所述通信模块读取所述电压表测量到的电压，若所述电压为所述电池的正常输出电压，则所述处理器提示控制闭合开关以进行诊断工作。
为解决上述技术问题，第四方面，本申请实施例中提供给了一种充电桩，包括第一方面的诊断设备或第二方面的诊断设备。
本申请实施例的有益效果：区别于现有技术的情况，本申请实施例提供的电动汽车绝缘检测功能的失效诊断系统，包括通信连接的诊断设备和服务器，其中，诊断设备包括直流总线、N个检测电阻群和 设备地，N个检测电阻群一一对应于N个阻值区域，每个检测电阻群包括一个正极检测电阻和一个负极检测电阻，正极检测电阻通过第一开关连接直流总线的正极端和设备地，负极检测电阻通过第二开关连接直流总线的负极端和设备地。当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极，诊断设备与电动汽车通信连接。诊断设备每次控制正极检测电阻和负极检测电阻中的任一个检测电阻连接的开关闭合，该开关为第一开关和第二开关中的一个。诊断设备每次控制开关闭合后，读取电动汽车反馈的针对检测电阻的测量阻值。诊断设备根据检测电阻的测量阻值和检测电阻的实际阻值，确定电动汽车针对该检测电阻的测量偏差。诊断设备将测量偏差上传至服务器，服务器根据电动汽车针对检测电阻的至少一个测量偏差，确定电动汽车的绝缘检测功能正常或失效。
在此诊断系统中，诊断设备能够准确监测到电动汽车对外界电阻的测量偏差，服务器基于测量偏差可以确定电动汽车对外界电阻的检测是否准确，若测量准确，则绝缘检测功能正常，若测量不准确，则绝缘检测功能失效。基于N个检测电阻群一一对应于N个阻值区间，从而，在多次诊断中，诊断系统能够检测到电动汽车对各个阻值区间的电阻的测量准确性，使得诊断结果更加准确。
附图说明
一个或多个实施例通过与之对应的附图中的图片进行示例性说明，这些示例性说明并不构成对实施例的限定，附图中具有相同参考数字标号的元件表示为类似的元件，除非有特别申明，附图中的图不构成比例限制。
图1为本申请一些实施例中电池的电池管理系统的结构示意图；
图2为本申请一些实施例中电动汽车绝缘检测功能的失效诊断系统的结构示意图；
图3为本申请一些实施例中诊断设备的结构示意图。
具体实施方式
下面结合具体实施例对本申请进行详细说明。以下实施例将有助于本领域的技术人员进一步理解本申请，但不以任何形式限制本申请。应当指出的是，对本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进。这些都属于本申请的保护范围。
为了使本申请的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅用以解释本申请，并不用于限定本申请。
需要说明的是，如果不冲突，本申请实施例中的各个特征可以相互结合，均在本申请的保护范围之内。另外，虽然在装置示意图中进行了功能模块划分，在流程图中示出了逻辑顺序，但是在某些情况下，可以以不同于装置中的模块划分，或流程图中的顺序执行所示出或描述的步骤。此外，本文所采用的“第一”、“第二”、“第三”等字样并不对数据和执行次序进行限定，仅是对功能和作用基本相同的相同项或相似项进行区分。
除非另有定义，本说明书所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。本说明书中在本申请的说明书中所使用的术语只是为了描述具体的实施方式的目的，不是用于限制本申请。本说明书所使用的术语“和/或”包括一个或多个相关的所列项目的任意的和所有的组合。
此外，下面所描述的本申请各个实施方式中所涉及到的技术特征只要彼此之间未构成冲突就可以相互组合。
在介绍本申请的技术方案之前，首先介绍电动汽车的绝缘检测功能。该绝缘检测功能是主要依靠电池自带的电池管理系统(BATTERY MANAGEMENT SYSTEM,BMS)检测电池正极对地和负极对地的绝缘阻值。若电池正极对地和负极对地的绝缘阻值大，则电池与外部环境之间的绝缘性越好。若电池正极对地和负极对地的绝缘阻值小，存在漏电触电风险，则需要电池管理系统上报告警信息，以及及时切断电池的供电输出端。可以理解的是，这里的供电输出端可以是电池的正极和负极，正极和负极与电动汽车内部的直流总线连接，为驱动系统供电。
其中，电池管理系统(BATTERY MANAGEMENT SYSTEM,BMS)，作为电池的保护和管理单元。如图1所示，电池100包括电池本体10和电池管理系统20，电池本体10可以为电芯、一个或多个电芯模组。
电池管理系统20包括电压采样模块21、电流采样模块22、绝缘检测模块23、温度传感器24、控制器25和开关电路26等。其中，电压采样模块21用于实时采集电池本体10的电压、被动均衡电量等。电流采样模块22用于对电池本体10在充放电过程中的电流进行采样。绝缘检测模块23用于检测电池 本体10正极对地和负极对地的绝缘阻值。若阻值越大，则电池本体10正极对地和负极对地的绝缘性好，则电池与外部环境之间的绝缘性越好。温度传感器24用于实时采集电池本体10的温度。
可以理解的是，上述电压采样模块21、电流采样模块22和绝缘检测模块23可以由现有的芯片模组(例如集成电路IC)或本领域常规电路实现，在此不详细介绍电压采样模块21、电流采样模块22和绝缘检测模块23的电路结构。温度传感器24可以由现有的热电阻或热电偶等实现，在此不详细介绍温度传感器24的结构和原理。
电压采样模块21、电流采样模块22和绝缘检测模块23将采集到的数据传输至控制器25(MCU)，控制器25根据采集到的数据确定电池100所需的欠压、过压、过流、短路、过温、低温和绝缘阻值大小等异常状态对应的保护措施，然后根据确定的保护措施，控制开关电路26选择性地断开或导通电池100与外部设备30(负载、充电器或诊断设备等)的连接，以实施该确定的保护措施。
在本申请发明人所知晓的一些绝缘检测方案中，车端BMS绝缘检测主要有电桥法和信号注入法。其中，电桥法是在外部绝缘环境发生变化时，获取从外部绝缘环境发生变化到电气环境达到稳态时的静置时间和绝缘电阻，在外部绝缘环境发生不同程度的变化后，能准确并及时的获取静置时间并计算绝缘电阻，保证及时响应外部绝缘环境变化，避免使用者人身安全受到威胁。信号注入法是绝缘检测系统根据电池组总压选择合适的PWM脉冲信号，并注入电动汽车高压电气子系统，再采集采样电阻两侧的电压信号，计算出电动汽车的绝缘电阻值。
按照行业标准，当检测到电池正极对地或负极对地的绝缘阻值低于100Ω/V时，确定为严重不绝缘故障，车辆高压系统(即电池)应立即停止输出，并告警通知驾乘人员。
然而，导致绝缘性差、高压漏电的因素主要有碰撞、破损、漏液、潮湿、腐蚀等，这些因素发生过程比较缓慢，并且发生的概率较低，并且这些因素也会造成BMS的绝缘检测功能失效，另外通信故障和测量误差等原因也会导致绝缘检测功能无法正常保护或告警。例如，有些车辆可能使用几年或行驶几十万公里都没有发生绝缘问题，缺少对车辆绝缘检测功能自身的检测，当真正的高压漏电危险发生时，系统可能误报甚至不报告警，严重时造成人员伤亡。
针对上述问题，本申请一些实施例提供了一种电动汽车绝缘检测功能的失效诊断系统。请参阅图2，图2为本申请一些实施例中电动汽车绝缘检测功能的失效诊断系统的结构示意图，该系统包括通信连接的诊断设备和服务器。
服务器可以为本地物理服务器，也可以是云设备，例如：云服务器、云主机、云服务平台、云计算平台等。在图2中，服务器为云平台。云平台通过4G、5G或WIFI等无线网络与诊断设备通信连接。在一些实施例中，两者遵循的通信协议可以是TCP/IP、NETBEUI和IPX/SPX等协议。
可以理解的是，服务器可以与多个诊断设备通信连接，从而，电动汽车在不同的地方采用不同的诊断设备诊断绝缘检测功能，各诊断设备可以将诊断数据上传至服务器，服务器基于诊断数据确定诊断结果。从而，服务器上可以保存电动汽车对应的历史诊断结果，方便查看，此外，还不受诊断设备所在地的约束，电动汽车可以在具有诊断设备的地方随时进行诊断，不需要每次前往一个地点，更加灵活。
在一些实施例中，失效诊断系统中的诊断设备可以是汽车维修点专用的诊断设备，不仅具有绝缘检测功能，还能检测汽车故障，用户可以利用它迅速地读取汽车电控系统中的故障，并通过液晶显示屏显示故障信息，迅速查明发生故障的部位及原因。
在一些实施例中，失效诊断系统中的诊断设备可以集成在充电桩中，在电动汽车充电前或充电后定期诊断绝缘检测功能是否有效，及时发现绝缘检测功能失效问题，提高了便利性和时效性。
具体地，请再次参阅图2，诊断设备包括直流总线、N个检测电阻群和设备地。其中，N个检测电阻群一一对应于N个阻值区域，每个检测电阻群包括一个正极检测电阻和一个负极检测电阻。各正极检测电阻分别通过第一开关连接直流总线的正极端和设备地，各负极检测电阻分别通过第二开关连接直流总线的负极端和设备地。当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极。设备地是指使用人员能够触碰到的设备外壳。
其中，N是大于或等于1的整数，例如，N可以为4，则有4个不同阻值区间的检测电阻群，即包括4个阻值不同的正极检测电阻和4个阻值不同的负极检测电阻。第一开关的数量可以基于类型确定，例如若第一开关为单刀开关，则一个正极检测电阻通过一个第一开关连接直流总线的正极端和设备地，若第一开关为单刀双掷开关，则两个正极检测电阻通过一个第一开关连接直流总线的正极端和设备地。第二开关的数量可以基于类型确定，例如若第二开关为单刀开关，则一个负极检测电阻通过一个第二开关连接直流总线的正极端和设备地，若第二开关为单刀双掷开关，则两个负极检测电阻通过一个第二开关连接直流总线的正极端和设备地。图2简化示出了任意一个检测电阻群中正极检测电阻Rpi和对应的第一开关Kpi连接于直流总线的正极端和设备地之间，负极检测电阻Rni和对应的第二开关Kni连接于直 流总线的负极端和设备地之间。
可以理解的是，当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极，若第一开关Kpi闭合，则相当于在电池正极和车辆地之间接入一个正极检测电阻Rpi，若第二开关Kni闭合，则相当于在电池负极和车辆地之间接入一个负极检测电阻Rni。这里车辆地是指使用人员能够触碰到的车辆外壳，可以理解的是，车辆地和设备地均是接地端，设备地可以等同于车辆地。
可以理解的是，理论上电池正极对地的绝缘电阻和负极对地的绝缘电阻均无穷大，以达到绝缘保护效果。正极检测电阻和负极检测电阻均小于电池正极对地的绝缘电阻和负极对地的绝缘电阻。从而，当任意一个开关闭合时，相当于在电池和车辆地之间接入一个检测电阻，使得电池对地不绝缘。正常情况下，电池管理系统的绝缘检测模块23会检测到电池对地的阻值，发现阻值小绝缘性差，存在漏电触电风险，则电池管理系统会上报告警信息，以及及时切断电池的供电输出端。
可以理解的是，准确测量电池对地的绝缘阻值是触发绝缘保护功能的前提，通常车辆绝缘检测功能在测量到系统绝缘阻值定量值低于100Ω/V时会触发严重故障，系统绝缘阻值定量值在100Ω/V～500Ω/V之间时会触发轻微报警。这里，系统绝缘阻定量值指正极对地和负极对地中绝缘阻值较小的值。可以理解的是，对于不同工作电压的车辆，系统绝缘电阻定量值也不同。
为了诊断电池管理系统(BMS)对各个阻值区间的电阻的检测精度，设置N个不同阻值区间的检测电阻群(以N为4为例)，覆盖4个阻值区间。例如，在0Ω/V～100Ω/V、100Ω/V～500Ω/V、500Ω/V～2000Ω/V和大于2000Ω/V这4个阻值区间中各选择一个电阻值作为正极检测电阻和负极检测电阻的阻值。如下表1所示，4个正极检测电阻、4个负极检测电阻的阻值分布在0Ω/V～100Ω/V、100Ω/V～500Ω/V、500Ω/V～2000Ω/V和大于2000Ω/V这4个阻值区间，对于每个阻值区间，不同工作电压的车辆，系统绝缘电阻定量值也不同。同一阻值区间的正极检测电阻或负极检测电阻均小于不同车辆的系统绝缘电阻定量。
表1，正极检测电阻和负极检测电阻的阻值设置
基于图2中诊断设备的结构，诊断设备每次控制正极检测电阻和负极检测电阻中的任一个检测电阻连接的开关闭合，该开关为第一开关和第二开关中的一个。当开关闭合后，相当于在电池和车辆地之间接入一个检测电阻，电动汽车的电池管理系统会测量该检测电阻的阻值。基于诊断设备和电动汽车通信连接，从而，诊断设备每次控制开关闭合后，可以读取电动汽车反馈的针对检测电阻的测量阻值。例如，对于正极检测电阻Rpi，控制其对应的第一开关Kpi闭合后，电池管理系统的绝缘检测模块23会测量电池正极对地的阻值，即测量正极检测电阻Rpi的阻值，这里测量到的阻值称为测量阻值Rpi_read。从而，诊断设备读取电动汽车反馈的针对检测电阻Rpi的测量阻值Rpi_read。
诊断设备根据检测电阻的测量阻值和检测电阻的实际阻值，确定电动汽车针对该检测电阻的测量偏差。在一些实施例中，可以采用如下公式计算正极检测电阻的测量偏差：
其中，Rpi为第i个正极检测电阻，Rpi_read为第i个正极检测电阻对应的测量阻值。
同理，采用如下公式计算负极检测电阻的测量偏差：
其中，Rni为第i个负极检测电阻，Rni_read为第i个负极检测电阻对应的测量阻值。
诊断设备将测量偏差上传至服务器，服务器根据电动汽车针对检测电阻的测量偏差，确定电动汽车 的绝缘检测功能正常或失效。若测量偏差小，说明电动汽车对对地电阻测量准确，则绝缘检测功能正常，若测量偏差大，说明电动汽车对对地电阻测量不准确，则绝缘检测功能失效。
可以理解的是，在一些实施例中，连续几次诊断时，诊断设备可以控制同一个检测电阻连接的开关闭合，从而，服务器得到电动汽车针对该该检测电阻的至少一个测量偏差，基于至少一个测量偏差，能够准确地确定电动汽车的绝缘检测功能正常或失效，避免诊断误差。
在一些实施例中，连续几次诊断时，诊断设备可以控制不同的检测电阻连接的开关闭合，从而，服务器得到电动汽车针对多个检测电阻的测量偏差。基于N个检测电阻群一一对应于N个阻值区间，从而，在多次诊断中，诊断系统能够检测到电动汽车对各个阻值区间的电阻的测量准确性，使得绝缘检测功能的诊断结果更加准确。
在一些实施例中，诊断设备依次控制N个检测电阻群中的一个检测电阻群对应的第一开关和第二开关闭合后，诊断设备再依次控制N个检测电阻群中的下一个检测电阻群对应的第一开关和第二开关闭合。以N为4进行示例性说明，第1个检测电阻群包括正极检测电阻Rp1、负极检测电阻Rn1，第2个检测电阻群包括正极检测电阻Rp2、负极检测电阻Rn2，第3个检测电阻群包括正极检测电阻Rp3、负极检测电阻Rn3，第4个检测电阻群包括正极检测电阻Rp4、负极检测电阻Rn4。在一些实施例中，诊断设备依次控制Rp1和Rn1闭合后，得到两个测量阻值。接着，诊断设备依次控制Rp2和Rn2闭合后，得到两个测量阻值。接着诊断设备依次控制Rp3和Rn3闭合后，得到两个测量阻值。接着，诊断设备依次控制Rp4和Rn4闭合后，得到两个测量阻值。经过上述轮流控制开关闭合，得到N个检测电阻群对应的2N个测量偏差。
可以理解的是，在一些实施例中，诊断设备依次控制N个正极检测电阻对应的第一开关和N个负极检测电阻对应的第二开关轮流闭合，得到2N个测量阻值。在此实施例中，2N个检测电阻对应的开关的闭合顺序不做限制，保证这2N个检测电阻对应的开关分别闭合即可。例如，轮流闭合完N个正极检测电阻对应的第一开关后，再轮流闭合N个负极检测电阻对应的第二开关。
然后，诊断设备将N个检测电阻群对应的测量偏差(2N个测量偏差)上传至服务器，服务器根据N个检测电阻群对应的测量偏差，确定电动汽车的绝缘检测功能正常或失效。例如，若N个检测电阻群对应的测量偏差中存在大于或等于偏差阈值的测量偏差，则确定电动汽车的绝缘检测功能失效；若N个检测电阻群对应的测量偏差均在一定范围内，则确定电动汽车的绝缘检测功能正常。
在此实施例中，诊断设备分别控制N个检测电阻群中的检测电阻对应的开关闭合，即分别单独导通2N个检测电阻，得到2N个测量偏差，服务器基于2N个测量偏差进行诊断。例如，若N个检测电阻群对应的测量偏差中存在大于或等于偏差阈值的测量偏差，则确定电动汽车的绝缘检测功能失效；若N个检测电阻群对应的测量偏差均在一定范围内，则确定电动汽车的绝缘检测功能正常。
基于N个检测电阻群对应N个阻值区间，从而，诊断系统在每次诊断时，能够检测到电动汽车对各个阻值区间的电阻的测量准确性，使得绝缘检测功能的诊断结果更加准确。
在一些实施例中，若服务器连续第一预设次数检测到N个检测电阻群对应的测量偏差中存在目标测量偏差大于或等于偏差阈值，则确定电动汽车的绝缘检测功能失效。其中，目标测量偏差为N个检测电阻群对应的测量偏差中的任意一个。
其中，第一预设次数可以由本领域技术人员根据实际情况而设置，例如，第一预设次数为3次。在此实施例中，诊断系统对电动汽车进行了多次诊断，每次诊断获取电动汽车反馈的针对2N个检测电阻的测量阻值，得到2N个测量偏差。若连续3次检测到2N个测量偏差中出现大于或等于偏差阈值的目标测量偏差，则说明电动汽车针对检测电阻的测量值不准确，电动汽车无法准确采集对地电阻的阻值，从而，影响绝缘检测功能，使得绝缘检测功能失效。
在此实施例中，基于服务器可以与多个诊断设备通信连接，多个诊断设备分别将测量数据发送给服务器，由服务器确定诊断结果。因此，电动汽车可以在不同的诊断设备上进行多次诊断，不受诊断设备的地点约束，若服务器连续第一预设次数检测到电动汽车对外界电阻测量不准确，则判定该电动汽车的绝缘检测功能已失效。通过连续第一预设次数的约束，能够减少误诊断概率，提高诊断的可靠性。
在一些实施例中，诊断设备依次控制N个检测电阻群中的一个检测电阻群对应的第一开关和第二开关闭合后，诊断设备再依次控制N个检测电阻群中的下一个检测电阻群对应的第一开关和第二开关闭合。
诊断设备每次得到一个检测电阻群对应的至少一个测量偏差后，将该检测电阻群对应的至少一个测量偏差上传至服务器，从而，服务器根据该检测电阻群对应的至少一个测量偏差，确定电动汽车的绝缘检测功能正常或失效。
例如，对于任意一个检测电阻群，该检测电阻群包括正极检测电阻Rpi和负极检测电阻Rni，诊断设备依次控制正极检测电阻Rpi对应的第一开关闭合、负极检测电阻Rni对应的第二开关闭合，分别得 到两个测量电阻，然后再基于Rpi和Rni的实际阻值，分别得到两个测量偏差。诊断设备在得到正极检测电阻Rpi对应的测量偏差或负极检测电阻Rni对应的测量偏差中的至少一个时，将至少一个测量偏差上传给服务器，例如，诊断设备在得到正极检测电阻Rpi对应的测量偏差或负极检测电阻Rni对应的测量偏差后将此测量偏差上传给服务器，或者，诊断设备在得到正极检测电阻Rpi对应的测量偏差和负极检测电阻Rni对应的测量偏差后将这两个测量偏差上传给服务器。从而，当诊断设备采集到电动汽车针对检测电阻的测量阻值时，服务器即可实时确定电动汽车针对该检测电阻的测量是否异常，从而，确定绝缘检测功能正常或失效。例如，若测量偏差大于偏差阈值，则测量异常，绝缘检测功能失效；若测量偏差小于或等于偏差阈值，则测量准确，绝缘检测功能正常。
在此实施例中，对每个检测电阻群中的检测电阻采集测量阻值后，进行实时上传，使得服务器能够实时确认该检测电阻的测量是否异常，从而，实时确定绝缘检测功能正常或失败。
基于理论上电池正极对地的绝缘电阻和负极对地的绝缘电阻均无穷大，以达到绝缘保护效果，正极检测电阻和负极检测电阻均小于电池正极对地的绝缘电阻和负极对地的绝缘电阻。从而，当阻值区间最小的检测电阻群对应的第一开关或第二开关闭合后，相当于在电池和车辆地之间接入一个较小的电阻(小于100Ω/V)，使得电动汽车对地不绝缘，发生漏电。正常情况下，电池管理系统的绝缘检测模块23会检测到电池对地的阻值，发现阻值小绝缘性差，存在漏电触电风险，则电池管理系统会上报告警信息，以及及时切断电池的供电输出端。
在一些实施例中，诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，读取电动汽车的反馈信息；诊断设备根据反馈信息，确定电动汽车的绝缘检测功能正常或失效。
以阻值区间最小的检测电阻群为Rp1和Rn1为例进行示例性说明，诊断设备控制Rp1对应的第一开关闭合，使得电动汽车的电池的正极端短路。在绝缘检测功能正常的情况下，电动汽车发出的反馈信息包括绝缘告警信息，即提醒用户发生了短路漏电事故；在绝缘检测功能失效的情况下，电动汽车发出的反馈信息不包括绝缘告警信息，无法提醒用户。然后，诊断设备控制Rn1对应的第二开关闭合，使得电动汽车的电池的负极端短路。在绝缘检测功能正常的情况下，电动汽车发出的反馈信息包括绝缘告警信息，提醒用户发送了短路漏电事故；在绝缘检测功能失效的情况下，电动汽车发出的反馈信息不包括绝缘告警信息，无法提醒用户。
可以理解的是，每当诊断设备控制一个开关闭合，诊断设备能够读取到电动汽车的反馈信息。在诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，能够读取到两个反馈信息，若这两个反馈信息均包括告警信息，则说明电动汽车的绝缘检测功能正常；若这两个反馈信息中的至少一个不包括告警信息，则说明电动汽车的绝缘检测功能失效。
在此方案中，诊断设备能够准确监测到电动汽车的绝缘检测功能是否告警正常，及时检测出因通信故障而导致绝缘检测功能失效的事件。
在一些实施例中，诊断设备将至少一个反馈信息上传至服务器，服务器根据至少一个反馈信息确定电动汽车的绝缘监测功能正常或失效。
可以理解的是，每当诊断设备控制一个开关闭合，诊断设备能够读取到电动汽车的反馈信息。在诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，能够读取到两个反馈信息。在此实施例中，诊断设备将至少一个反馈信息上传至服务器，例如上传一个正极对应的反馈信息、一个负极对应的反馈信息或两个反馈信息。从而，服务器能够根据至少一个反馈信息确定电动汽车的绝缘检测功能正常或失效。例如，当服务器接收到两个反馈信息时，若这两个反馈信息均包括告警信息，则说明电动汽车的绝缘检测功能正常；若这两个反馈信息中的至少一个不包括告警信息，则说明电动汽车的绝缘检测功能失效。
在此实施例中，诊断设备将至少一个反馈信息上传至服务器，由服务器确定电动汽车的绝缘监测功能正常或失效，从而，经过多次诊断，服务器能够保存多次诊断的结果，分析出诊断结构的趋势。此外，基于服务器可以与多个诊断设备通信连接，多个诊断设备分别将反馈信息发送给服务器，由服务器确定诊断结果，从而，电动汽车可以在不同的诊断设备上进行多次诊断，不受诊断设备的地点约束，还能追溯历史诊断结果，使得诊断更加准确可靠。
通过服务器将电动汽车在不同诊断设备上检测到的反馈信息存储建档，通过分析反馈信息的历史趋势，能够准确确定电动汽车的绝缘检测功能是否失效，能够减少误诊概率，及时发现功能失效问题，提升了安全性。服务器可以通过诊断设备屏幕、打印设备、手机APP、管理后台等方式向用户呈现诊断结果，如果判定车辆绝缘检测功能已失效，建议用户尽快到维修店进行排查修复。
在一些实施例中，若服务器连续第二预设次数检测到至少一个反馈信息中存在告警异常，则确定电动汽车的绝缘检测功能失效。
这里，告警异常是指在阻值区间最小的检测电阻群对应的第一开关或第二开关闭合的情况下，电动汽车的反馈信息本来应该包括告警信息，而未包括告警信息。
其中，第二预设次数可以由本领域技术人员根据实际情况而设置，例如，第二预设次数为3次。在此实施例中，诊断系统对电动汽车进行多次诊断，每次诊断获取电动汽车发出的反馈信息。若连续3次诊断，3次的反馈信息中均存在告警异常，则说明电动汽车在短路漏电的情况下未准确上报告警，出现上报故障，绝缘检测功能失效。
在此实施例中，若服务器连续第二预设次数检测到电动汽车出现上报故障，则判定该电动汽车的绝缘检测功能已失效。通过连续第二预设次数的约束，能够减少误诊断概率，提高诊断的可靠性。
在一些实施例中，请继续参阅图2，诊断设备还包括电压表，电压表连接于直流总线的正极端和负极端之间。当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极，从而，电压表可以测量电池的电压。
在电压表测量到电池的电压后，诊断设备读取电压表测量到的电动汽车的电池的电压，若电压为该电池的正常输出电压，则提示控制闭合开关以进行诊断工作。可以理解的是，若电压为该电池的正常输出电压，则说明电动汽车的电池与诊断设备连接正常，从而，可以开始诊断工作，因此，提示控制闭合开关以进行诊断工作。
在此实施例中，通过电压表测量电动汽车电池的电压，在确保电动汽车的电池与诊断设备连接正常的情况下提示控制关闭开关以进行诊断工作，使得诊断设备更加准确安全。
在一些实施例中，诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，若诊断设备分别读取到电压表测量到的电压为0，则确定电动汽车的电池正极诊断结果正常。
可以理解的是，在阻值区间最小的检测电阻群对应的第一开关闭合后，电动汽车的电池正极对地电阻为阻值最小的正极检测电阻，即电池正极对地不绝缘，发生了正极漏电风险，此时，若电池管理系统的绝缘检测模块正常工作，则应触发切断保护，即及时切断电池的供电输出端，使得电池的输出电压为0。因此，在阻值区间最小的检测电阻群对应的第一开关闭合的情况下，若诊断设备读取到电压表测量到的电压为0，说明电池管理系统的绝缘检测模块能够对正极绝缘故障及时触发保护，因此，确定电动汽车的电池正极诊断结果正常。
同理，阻值区间最小的检测电阻群对应的第二开关闭合后，电动汽车的电池负极对地电阻为阻值最小的负极检测电阻，即电池负极对地不绝缘，发生了负极漏电风险，此时，若电池管理系统的绝缘检测模块正常工作，则应触发切断保护，即及时切断电池的供电输出端，使得电池的输出电压为0。因此，在阻值区间最小的检测电阻群对应的第二开关闭合的情况下，若诊断设备读取到电压表测量到的电压为0，说明电池管理系统的绝缘检测模块能够对负极绝缘故障及时触发保护，因此，确定电动汽车的电池负极诊断结果正常。
在此实施例中，通过电压表监测电动汽车的电池发生漏电风险后电池管理系统能否及时触发切断保护，能够准确确定电动汽车的电池正极或负极诊断结果是否正常。
在一些实施例中，请再次参阅图2，该失效诊断系统还包括汽车通信接口设备(vehicle communication interface，VCI)，汽车通信接口设备用于通信连接诊断设备和电动汽车。汽车通信接口设备，设置于汽车的方向盘周边。汽车通信接口设备一端口可用于连接于汽车的OBD接口，另一端口可用于连接于诊断设备的OBD接口。
综上所述，本申请实施例提供的电动汽车绝缘检测功能的失效诊断系统，包括通信连接的诊断设备和服务器，其中，诊断设备包括直流总线、N个检测电阻群和设备地，N个检测电阻群一一对应于N个阻值区域，每个检测电阻群包括一个正极检测电阻和一个负极检测电阻，正极检测电阻通过第一开关连接直流总线的正极端和设备地，负极检测电阻通过第二开关连接直流总线的负极端和设备地。当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极，诊断设备与电动汽车通信连接。诊断设备每次控制正极检测电阻和负极检测电阻中的任一个检测电阻连接的开关闭合，该开关为第一开关和第二开关中的一个。诊断设备每次控制开关闭合后，读取电动汽车反馈的针对检测电阻的测量阻值。诊断设备根据检测电阻的测量阻值和检测电阻的实际阻值，确定电动汽车针对该检测电阻的测量偏差。诊断设备将测量偏差上传至服务器，服务器根据电动汽车针对检测电阻的至少一个测量偏差，确定电动汽车的绝缘检测功能正常或失效。
在此诊断系统中，诊断设备能够准确监测到电动汽车对外界电阻的测量偏差，服务器基于测量偏差可以确定电动汽车对外界电阻的检测是否准确，若测量准确，则绝缘检测功能正常，若测量不准确，则绝缘检测功能失效。基于N个检测电阻群一一对应于N个阻值区间，从而，在多次诊断中，诊断系统能够检测到电动汽车对各个阻值区间的电阻的测量准确性，使得诊断结果更加准确。
本申请一些实施例还提供了一种诊断设备，请参阅图3，该诊断设备包括：直流总线、N个检测电阻群、设备地和处理器、通信模块。
其中，处理器可以是中央处理器(central processing unit，CPU)，网络处理器(network processor，NP)，硬件芯片或者其任意组合。在一些实施例中，通信模块可以包括通信接口和网络天线，该通信接口用于与电动汽车进行有线通信连接，该网络天线可以和服务器之间无线通信连接。
N个检测电阻群一一对应于N个阻值区间，每个检测电阻群包括一个正极检测电阻和一个负极检测电阻，正极检测电阻通过第一开关连接直流总线的正极端和设备地，负极检测电阻通过第二开关连接直流总线的负极端和设备地。当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极。设备地是指使用人员能够触碰到的设备外壳。
N是大于或等于1的整数，例如，N可以为4，则有4个不同阻值区间的检测电阻群，即包括4个阻值不同的正极检测电阻和4个阻值不同的负极检测电阻。图3简化示出了任意一个检测电阻群中正极检测电阻Rpi和对应的第一开关Kpi连接于直流总线的正极端和设备地之间，负极检测电阻Rni和对应的第二开关Kni连接于直流总线的负极端和设备地之间。可以理解的是，在图3中，其它检测电阻群未示出。
可以理解的是，当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极，若第一开关Kpi闭合，则相当于在电池正极和设备地之间接入一个正极检测电阻Rpi，若第二开关Kni闭合，则相当于在电池负极和设备地之间接入一个负极检测电阻Rni。这里，设备地是接地端。
可以理解的是，理论上电池正极对地的绝缘电阻和负极对地的绝缘电阻均无穷大，以达到绝缘保护效果。正极检测电阻和负极检测电阻均小于电池正极对地的绝缘电阻和负极对地的绝缘电阻。从而，当任意一个开关闭合时，相当于在电池和车辆地之间接入一个检测电阻，使得电池对地不绝缘。正常情况下，电池管理系统的绝缘检测模块23会检测到电池对地的阻值，发现阻值小绝缘性差，存在漏电触电风险，则电池管理系统会上报告警信息，以及及时切断电池的供电输出端。
可以理解的是，准确测量电池对地的绝缘阻值是触发绝缘保护功能的前提，通常车辆绝缘检测功能在测量到系统绝缘阻值定量值低于100Ω/V时会触发严重故障，系统绝缘阻值定量值在100Ω/V～500Ω/V之间时会触发轻微报警。这里，系统绝缘阻定量值指正极对地和负极对地中绝缘阻值较小的值。可以理解的是，对于不同工作电压的车辆，系统绝缘电阻定量值也不同。
为了诊断电池管理系统(BMS)对各个阻值区间的电阻的检测精度，设置N个不同阻值区间的检测电阻群(以N为4为例)，覆盖4个阻值区间。例如，在0Ω/V～100Ω/V、100Ω/V～500Ω/V、500Ω/V～2000Ω/V和大于2000Ω/V这4个阻值区间中各选择一个电阻值作为正极检测电阻和负极检测电阻的阻值。
正极检测电阻和负极检测电阻的阻值可以参考表1进行设置，4个正极检测电阻、4个负极检测电阻的阻值分布在0Ω/V～100Ω/V、100Ω/V～500Ω/V、500Ω/V～2000Ω/V和大于2000Ω/V这4个阻值区间，对于每个阻值区间，不同工作电压的车辆，系统绝缘电阻定量值也不同。同一阻值区间的正极检测电阻或负极检测电阻均小于不同车辆的系统绝缘电阻定量。
基于图3中诊断设备的结构，处理器每次控制正极检测电阻和负极检测电阻中的任一个检测电阻连接的开关闭合，该开关为第一开关和第二开关中的一个。当开关闭合后，相当于在电池和车辆地之间接入一个检测电阻，电动汽车的电池管理系统会测量该检测电阻的阻值。基于诊断设备和电动汽车通过通信模块通信连接，从而，处理器每次控制开关闭合后，通信模块可以读取电动汽车反馈的针对检测电阻的测量阻值。例如，对于正极检测电阻Rpi，控制其对应的第一开关Kpi闭合后，电池管理系统的绝缘检测模块23会测量电池正极对地的阻值，即测量正极检测电阻Rpi的阻值，这里测量到的阻值称为测量阻值Rpi_read。从而，通信模块读取电动汽车反馈的针对检测电阻Rpi的测量阻值Rpi_read。
处理器根据检测电阻的测量阻值和检测电阻的实际阻值，确定电动汽车针对该检测电阻的测量偏差。在一些实施例中，可以采用如下公式计算正极检测电阻的测量偏差：
其中，Rpi为第i个正极检测电阻，Rpi_read为第i个正极检测电阻对应的测量阻值。
同理，采用如下公式计算负极检测电阻的测量偏差：
其中，Rni为第i个负极检测电阻，Rni_read为第i个负极检测电阻对应的测量阻值。
处理器根据电动汽车针对检测电阻的测量偏差，确定电动汽车的绝缘检测功能正常或失效。若测量偏差小，说明电动汽车对对地电阻测量准确，则绝缘检测功能正常，若测量偏差大，说明电动汽车对对地电阻测量不准确，则绝缘检测功能失效。
可以理解的是，在一些实施例中，连续几次诊断时，处理器可以控制同一个检测电阻连接的开关闭合，从而，处理器得到电动汽车针对该该检测电阻的至少一个测量偏差，基于至少一个测量偏差，能够准确地确定电动汽车的绝缘检测功能正常或失效，避免诊断误差。
在一些实施例中，连续几次诊断时，处理器可以控制不同的检测电阻连接的开关闭合，从而，处理器得到电动汽车针对多个检测电阻的测量偏差。基于N个检测电阻群一一对应于N个阻值区间，从而，在多次诊断中，诊断设备能够检测到电动汽车对各个阻值区间的电阻的测量准确性，使得绝缘检测功能的诊断结果更加准确。
在一些实施例中，处理器依次控制N个检测电阻群中的一个检测电阻群对应的第一开关和第二开关闭合后，诊断设备再依次控制N个检测电阻群中的下一个检测电阻群对应的第一开关和第二开关闭合。以N为4进行示例性说明，第1个检测电阻群包括正极检测电阻Rp1、负极检测电阻Rn1，第2个检测电阻群包括正极检测电阻Rp2、负极检测电阻Rn2，第3个检测电阻群包括正极检测电阻Rp3、负极检测电阻Rn3，第4个检测电阻群包括正极检测电阻Rp4、负极检测电阻Rn4。在一些实施例中，诊断设备依次控制Rp1和Rn1闭合后，得到两个测量阻值。接着，诊断设备依次控制Rp2和Rn2闭合后，得到两个测量阻值。接着诊断设备依次控制Rp3和Rn3闭合后，得到两个测量阻值。接着，诊断设备依次控制Rp4和Rn4闭合后，得到两个测量阻值。经过上述轮流控制开关闭合，得到N个检测电阻群对应的2N个测量偏差。
可以理解的是，在一些实施例中，处理器依次控制N个正极检测电阻对应的第一开关和N个负极检测电阻对应的第二开关轮流闭合，得到2N个测量阻值。在此实施例中，2N个检测电阻对应的开关的闭合顺序不做限制，保证这2N个检测电阻对应的开关分别闭合即可。例如，轮流闭合完N个正极检测电阻对应的第一开关后，再轮流闭合N个负极检测电阻对应的第二开关。
然后，处理器根据N个检测电阻群对应的测量偏差，确定电动汽车的绝缘检测功能正常或失效。例如，若N个检测电阻群对应的测量偏差中存在大于或等于偏差阈值的测量偏差，则确定电动汽车的绝缘检测功能失效；若N个检测电阻群对应的测量偏差均在一定范围内，则确定电动汽车的绝缘检测功能正常。
在此实施例中，处理器分别控制N个检测电阻群中的检测电阻对应的开关闭合，即分别单独导通2N个检测电阻，得到2N个测量偏差，基于这2N个测量偏差进行诊断。例如，若N个检测电阻群对应的测量偏差中存在大于或等于偏差阈值的测量偏差，则确定电动汽车的绝缘检测功能失效；若N个检测电阻群对应的测量偏差均在一定范围内，则确定电动汽车的绝缘检测功能正常。
基于N个检测电阻群对应N个阻值区间，从而，诊断设备在每次诊断时，能够检测到电动汽车对各个阻值区间的电阻的测量准确性，使得绝缘检测功能的诊断结果更加准确。
在一些实施例中，若处理器连续第一预设次数检测到N个检测电阻群对应的测量偏差中存在目标测量偏差大于或等于偏差阈值，则确定电动汽车的绝缘检测功能失效。其中，目标测量偏差为N个检测电阻群对应的测量偏差中的任意一个。
其中，第一预设次数可以由本领域技术人员根据实际情况而设置，例如，第一预设次数为3次。在此实施例中，诊断设备对电动汽车进行了多次诊断，每次诊断获取电动汽车反馈的针对2N个检测电阻的测量阻值，得到2N个测量偏差。若连续3次检测到2N个测量偏差中出现大于或等于偏差阈值的目标测量偏差，则说明电动汽车针对检测电阻的测量值不准确，电动汽车无法准确采集对地电阻的阻值，从而，影响绝缘检测功能，使得绝缘检测功能失效。
在此实施例中，若处理器连续第一预设次数检测到电动汽车对外界电阻测量不准确，则判定该电动汽车的绝缘检测功能已失效。通过连续第一预设次数的约束，能够减少误诊断概率，提高诊断的可靠性。
在一些实施例中，处理器依次控制N个检测电阻群中的一个检测电阻群对应的第一开关和第二开关闭合后，该处理器再依次控制N个检测电阻群中的下一个检测电阻群对应的第一开关和第二开关闭合。
处理器每次得到一个检测电阻群对应的至少一个测量偏差后，根据该检测电阻群对应的至少一个测量偏差，确定电动汽车的绝缘检测功能正常或失效。
例如，对于任意一个检测电阻群，该检测电阻群包括正极检测电阻Rpi和负极检测电阻Rni，处理器依次控制正极检测电阻Rpi对应的第一开关闭合、负极检测电阻Rni对应的第二开关闭合，分别得到 两个测量电阻，然后再基于Rpi和Rni的实际阻值，分别得到两个测量偏差。处理器在得到正极检测电阻Rpi对应的测量偏差或负极检测电阻Rni对应的测量偏差中的至少一个时确定对应的测量偏差，例如，处理器在得到正极检测电阻Rpi对应的测量偏差或负极检测电阻Rni对应的测量偏差，或者，处理器在得到正极检测电阻Rpi对应的测量偏差和负极检测电阻Rni对应的测量偏差后，处理器即可实时确定电动汽车针对该检测电阻的测量是否异常，从而，确定绝缘检测功能正常或失效。例如，若测量偏差大于偏差阈值，则测量异常，绝缘检测功能失效；若测量偏差小于或等于偏差阈值，则测量准确，绝缘检测功能正常。
在此实施例中，对每个检测电阻群中的检测电阻采集测量阻值后，进行实时检测，使得诊断设备能够实时确认该检测电阻的测量是否异常，从而，实时确定绝缘检测功能正常或失败。
基于理论上电池正极对地的绝缘电阻和负极对地的绝缘电阻均无穷大，以达到绝缘保护效果，正极检测电阻和负极检测电阻均小于电池正极对地的绝缘电阻和负极对地的绝缘电阻。从而，当阻值区间最小的检测电阻群对应的第一开关或第二开关闭合后，相当于在电池和车辆地之间接入一个较小的电阻(小于100Ω/V)，使得电动汽车对地不绝缘，发生漏电。正常情况下，电池管理系统的绝缘检测模块23会检测到电池对地的阻值，发现阻值小绝缘性差，存在漏电触电风险，则电池管理系统会上报告警信息，以及及时切断电池的供电输出端。
在一些实施例中，处理器依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，读取电动汽车的反馈信息；诊断设备根据反馈信息，确定电动汽车的绝缘检测功能正常或失效。
以阻值区间最小的检测电阻群为Rp1和Rn1为例进行示例性说明，诊断设备控制Rp1对应的第一开关闭合，使得电动汽车的电池的正极端短路。在绝缘检测功能正常的情况下，电动汽车发出的反馈信息包括绝缘告警信息，即提醒用户发生了短路漏电事故；在绝缘检测功能失效的情况下，电动汽车发出的反馈信息不包括绝缘告警信息，无法提醒用户。然后，诊断设备控制Rn1对应的第二开关闭合，使得电动汽车的电池的负极端短路。在绝缘检测功能正常的情况下，电动汽车发出的反馈信息包括绝缘告警信息，提醒用户发送了短路漏电事故；在绝缘检测功能失效的情况下，电动汽车发出的反馈信息不包括绝缘告警信息，无法提醒用户。
可以理解的是，每当处理器控制一个开关闭合，通信模块能够读取到电动汽车的反馈信息。在处理器依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，通信模块能够读取到两个反馈信息，若这两个反馈信息均包括告警信息，则说明电动汽车的绝缘检测功能正常；若这两个反馈信息中的至少一个不包括告警信息，则说明电动汽车的绝缘检测功能失效。
在此方案中，诊断设备能够准确监测到电动汽车的绝缘检测功能是否告警正常，及时检测出因通信故障而导致绝缘检测功能失效的事件。
在一些实施例中，若处理器连续第二预设次数检测到至少一个反馈信息中存在告警异常，则确定电动汽车的绝缘检测功能失效。
这里，告警异常是指在阻值区间最小的检测电阻群对应的第一开关或第二开关闭合的情况下，电动汽车的反馈信息本来应该包括告警信息，而未包括告警信息。
其中，第二预设次数可以由本领域技术人员根据实际情况而设置，例如，第二预设次数为3次。在此实施例中，诊断设备对电动汽车进行多次诊断，每次诊断获取电动汽车发出的反馈信息。若连续3次诊断，3次的反馈信息中均存在告警异常，则说明电动汽车在短路漏电的情况下未准确上报告警，出现上报故障，绝缘检测功能失效。
在此实施例中，若处理器连续第二预设次数检测到电动汽车出现上报故障，则判定该电动汽车的绝缘检测功能已失效。通过连续第二预设次数的约束，能够减少误诊断概率，提高诊断的可靠性。
在一些实施例中，请继续参阅图3，诊断设备还包括电压表，电压表连接于直流总线的正极端和负极端之间。当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极，从而，电压表可以测量电池的电压。
在电压表测量到电池的电压后，处理器读取电压表测量到的电动汽车的电池的电压，若电压为该电池的正常输出电压，则提示控制闭合开关以进行诊断工作。可以理解的是，若电压为该电池的正常输出电压，则说明电动汽车的电池与诊断设备连接正常，从而，可以开始诊断工作，因此，提示控制闭合开关以进行诊断工作。
在此实施例中，通过电压表测量电动汽车电池的电压，在确保电动汽车的电池与诊断设备连接正常的情况下提示控制关闭开关以进行诊断工作，使得诊断设备更加准确安全。
在一些实施例中，处理器依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，若处理器分别读取到电压表测量到的电压为0，则确定电动汽车的电池正极诊断结果正常。
可以理解的是，在阻值区间最小的检测电阻群对应的第一开关闭合后，电动汽车的电池正极对地电阻为阻值最小的正极检测电阻，即电池正极对地不绝缘，发生了正极漏电风险，此时，若电池管理系统的绝缘检测模块正常工作，则应触发切断保护，即及时切断电池的供电输出端，使得电池的输出电压为0。因此，在阻值区间最小的检测电阻群对应的第一开关闭合的情况下，若处理器读取到电压表测量到的电压为0，说明电池管理系统的绝缘检测模块能够对正极绝缘故障及时触发保护，因此，确定电动汽车的电池正极诊断结果正常。
同理，阻值区间最小的检测电阻群对应的第二开关闭合后，电动汽车的电池负极对地电阻为阻值最小的负极检测电阻，即电池负极对地不绝缘，发生了负极漏电风险，此时，若电池管理系统的绝缘检测模块正常工作，则应触发切断保护，即及时切断电池的供电输出端，使得电池的输出电压为0。因此，在阻值区间最小的检测电阻群对应的第二开关闭合的情况下，若处理器读取到电压表测量到的电压为0，说明电池管理系统的绝缘检测模块能够对负极绝缘故障及时触发保护，因此，确定电动汽车的电池负极诊断结果正常。
在此实施例中，诊断设备通过电压表监测电动汽车的电池发生漏电风险后电池管理系统能否及时触发切断保护，能够准确确定电动汽车的电池正极或负极诊断结果是否正常。
综上所述，诊断设备能够准确监测到电动汽车对外界电阻的测量偏差，服务器基于测量偏差可以确定电动汽车对外界电阻的检测是否准确，若测量准确，则绝缘检测功能正常，若测量不准确，则绝缘检测功能失效。基于N个检测电阻群一一对应于N个阻值区间，从而，在多次诊断中，诊断设备能够检测到电动汽车对各个阻值区间的电阻的测量准确性，使得诊断结果更加准确。
本申请一些实施例还提供了一种诊断设备，该诊断设备包括直流总线、N个检测电阻群、设备地、处理器和通信模块。其中，处理器可以是中央处理器(central processing unit，CPU)，网络处理器(network processor，NP)，硬件芯片或者其任意组合。在一些实施例中，通信模块可以包括通信接口和网络天线，该通信接口用于与电动汽车进行有线通信连接，该网络天线可以和服务器之间无线通信连接。
N个检测电阻群一一对应于N个阻值区间，每个检测电阻群包括一个正极检测电阻和一个负极检测电阻，正极检测电阻通过第一开关连接直流总线的正极端和设备地，负极检测电阻通过第二开关连接直流总线的负极端和设备地。当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极。设备地是指使用人员能够触碰到的设备外壳。
N是大于或等于1的整数，例如，N可以为4，则有4个不同阻值区间的检测电阻群，即包括4个阻值不同的正极检测电阻和4个阻值不同的负极检测电阻。可以理解的是，当进行失效诊断时，直流总线的正极端连接电动汽车的电池正极，直流总线的负极端连接电动汽车的电池负极，若第一开关Kpi闭合，则相当于在电池正极和设备地之间接入一个正极检测电阻Rpi，若第二开关Kni闭合，则相当于在电池负极和设备地之间接入一个负极检测电阻Rni。这里，设备地是接地端。
可以理解的是，理论上电池正极对地的绝缘电阻和负极对地的绝缘电阻均无穷大，以达到绝缘保护效果。正极检测电阻和负极检测电阻均小于电池正极对地的绝缘电阻和负极对地的绝缘电阻。从而，当任意一个开关闭合时，相当于在电池和车辆地之间接入一个检测电阻，使得电池对地不绝缘。正常情况下，电池管理系统的绝缘检测模块23会检测到电池对地的阻值，发现阻值小绝缘性差，存在漏电触电风险，则电池管理系统会上报告警信息，以及及时切断电池的供电输出端。
可以理解的是，准确测量电池对地的绝缘阻值是触发绝缘保护功能的前提，通常车辆绝缘检测功能在测量到系统绝缘阻值定量值低于100Ω/V时会触发严重故障，系统绝缘阻值定量值在100Ω/V～500Ω/V之间时会触发轻微报警。这里，系统绝缘阻定量值指正极对地和负极对地中绝缘阻值较小的值。可以理解的是，对于不同工作电压的车辆，系统绝缘电阻定量值也不同。
为了诊断电池管理系统(BMS)对各个阻值区间的电阻的检测精度，设置N个不同阻值区间的检测电阻群(以N为4为例)，覆盖4个阻值区间。例如，在0Ω/V～100Ω/V、100Ω/V～500Ω/V、500Ω/V～2000Ω/V和大于2000Ω/V这4个阻值区间中各选择一个电阻值作为正极检测电阻和负极检测电阻的阻值。
正极检测电阻和负极检测电阻的阻值可以参考表1进行设置，4个正极检测电阻、4个负极检测电阻的阻值分布在0Ω/V～100Ω/V、100Ω/V～500Ω/V、500Ω/V～2000Ω/V和大于2000Ω/V这4个阻值区间，对于每个阻值区间，不同工作电压的车辆，系统绝缘电阻定量值也不同。同一阻值区间的正极检测电阻或负极检测电阻均小于不同车辆的系统绝缘电阻定量。
诊断设备每次控制正极检测电阻和负极检测电阻中的任一个检测电阻连接的开关闭合，该开关为第一开关和第二开关中的一个。当开关闭合后，相当于在电池和车辆地之间接入一个检测电阻，电动汽车的电池管理系统会测量该检测电阻的阻值。基于诊断设备和电动汽车通信连接，从而，诊断设备每次控 制开关闭合后，通信模块可以读取电动汽车反馈的针对检测电阻的测量阻值。例如，对于正极检测电阻Rpi，控制其对应的第一开关Kpi闭合后，电池管理系统的绝缘检测模块23会测量电池正极对地的阻值，即测量正极检测电阻Rpi的阻值，这里测量到的阻值称为测量阻值Rpi_read。从而，通信模块读取电动汽车反馈的针对检测电阻Rpi的测量阻值Rpi_read。
诊断设备根据检测电阻的测量阻值和检测电阻的实际阻值，确定电动汽车针对该检测电阻的测量偏差。在一些实施例中，可以采用如下公式计算正极检测电阻的测量偏差：
其中，Rpi为第i个正极检测电阻，Rpi_read为第i个正极检测电阻对应的测量阻值。
同理，采用如下公式计算负极检测电阻的测量偏差：
其中，Rni为第i个负极检测电阻，Rni_read为第i个负极检测电阻对应的测量阻值。
诊断设备的通信模块将测量偏差上传至服务器，服务器根据电动汽车针对检测电阻的测量偏差，确定电动汽车的绝缘检测功能正常或失效。若测量偏差小，说明电动汽车对对地电阻测量准确，则绝缘检测功能正常，若测量偏差大，说明电动汽车对对地电阻测量不准确，则绝缘检测功能失效。
可以理解的是，在一些实施例中，连续几次诊断时，诊断设备可以控制同一个检测电阻连接的开关闭合，从而，服务器得到电动汽车针对该该检测电阻的至少一个测量偏差，基于至少一个测量偏差，能够准确地确定电动汽车的绝缘检测功能正常或失效，避免诊断误差。
在一些实施例中，连续几次诊断时，诊断设备可以控制不同的检测电阻连接的开关闭合，从而，服务器得到电动汽车针对多个检测电阻的测量偏差。基于N个检测电阻群一一对应于N个阻值区间，从而，在多次诊断中，能够检测到电动汽车对各个阻值区间的电阻的测量准确性，使得绝缘检测功能的诊断结果更加准确。
本申请一些实施例还提供了一种充电桩，包括上述任意一个实施例中的诊断设备。其中，诊断设备的结构和功能与上述一些实施例中的诊断设备相同，在此不再重复赘述。
在电动汽车充电前或充电后，充电桩可以定期诊断绝缘检测功能是否有效，及时发现绝缘检测功能失效问题，提高了便利性和时效性。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (13)

  1. 一种电动汽车绝缘检测功能的失效诊断系统，包括通信连接的诊断设备和服务器，所述诊断设备包括直流总线、N个检测电阻群和设备地，N个所述检测电阻群一一对应于N个阻值区间，每个所述检测电阻群包括一个正极检测电阻和一个负极检测电阻，所述正极检测电阻通过第一开关连接所述直流总线的正极端和所述设备地，所述负极检测电阻通过第二开关连接所述直流总线的负极端和所述设备地，其中，N是大于或等于1的整数；所述直流总线的正极端用于连接电动汽车的电池正极，所述直流总线的负极端用于连接所述电动汽车的电池负极，所述诊断设备还用于与所述电动汽车通信连接；所述诊断设备每次控制所述正极检测电阻和所述负极检测电阻中的任一个检测电阻连接的开关闭合，所述开关为所述第一开关和所述第二开关中的一个；
    所述诊断设备每次控制所述开关闭合后，读取所述电动汽车反馈的针对所述检测电阻的测量阻值；
    所述诊断设备根据所述检测电阻的测量阻值和所述检测电阻的实际阻值，确定所述电动汽车针对所述检测电阻的测量偏差；
    所述诊断设备将所述测量偏差上传至所述服务器，所述服务器根据所述电动汽车针对所述检测电阻的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
  2. 根据权利要求1所述的系统，所述诊断设备依次控制所述N个检测电阻群中的一个检测电阻群对应的所述第一开关和所述第二开关闭合后，所述诊断设备再依次控制所述N个检测电阻群中的下一个检测电阻群对应的所述第一开关和所述第二开关闭合；
    所述诊断设备将所述N个检测电阻群对应的测量偏差上传至所述服务器，所述服务器根据所述N个检测电阻群对应的测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
  3. 根据权利要求2所述的系统，若所述服务器连续第一预设次数检测到所述N个检测电阻群对应的测量偏差中存在目标测量偏差大于或等于偏差阈值，则确定所述电动汽车的绝缘检测功能失效，所述目标测量偏差为所述N个检测电阻群对应的测量偏差中的任意一个。
  4. 根据权利要求1所述的系统，所述诊断设备依次控制所述N个检测电阻群中的一个检测电阻群对应的所述第一开关和所述第二开关闭合后，所述诊断设备再依次控制所述N个检测电阻群中的下一个检测电阻群对应的所述第一开关和所述第二开关闭合；
    所述诊断设备每次得到一个检测电阻群对应的至少一个测量偏差后，将所述检测电阻群对应的至少一个测量偏差上传至所述服务器，所述服务器根据所述检测电阻群对应的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
  5. 根据权利要求1-4任意一项所述的系统，所述诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，读取所述电动汽车的反馈信息；
    所述诊断设备根据所述反馈信息，确定所述电动汽车的绝缘检测功能正常或失效。
  6. 根据权利要求5所述的系统，所述诊断设备将至少一个所述反馈信息上传至所述服务器，所述服务器根据至少一个所述反馈信息确定所述电动汽车的绝缘监测功能正常或失效。
  7. 根据权利要求6所述的系统，若所述服务器连续第二预设次数检测到至少一个所述反馈信息中存在告警异常，则确定所述电动汽车的绝缘检测功能失效。
  8. 根据权利要求5所述的系统，所述诊断设备还包括电压表，所述电压表连接于所述直流总线的正极端和负极端之间；
    所述诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合后，若分别读取所述电压表测量到的电压为0，则确定所述电动汽车的绝缘检测功能正常。
  9. 根据权利要求8所述的系统，在所述诊断设备依次控制阻值区间最小的检测电阻群对应的第一开关和第二开关闭合之前，所述诊断设备读取所述电压表测量到的电压，若所述电压为所述电池的正常输出电压，则提示控制闭合开关以进行诊断工作。
  10. 根据权利要求1所述的系统，所述系统还包括汽车通信接口设备，所述汽车通信接口设备用于通信连接所述诊断设备和所述电动汽车。
  11. 一种诊断设备，包括直流总线、N个检测电阻群、设备地、处理器和通信模块；
    其中，N个所述检测电阻群一一对应于N个阻值区间，每个所述检测电阻群包括一个正极检测电阻和一个负极检测电阻，所述正极检测电阻通过第一开关连接所述直流总线的正极端和所述设备地，所述负极检测电阻通过第二开关连接所述直流总线的负极端和所述设备地，其中，N是大于或等于1的整数；
    所述直流总线的正极端用于连接电动汽车的电池正极，所述直流总线的负极端用于连接所述电动汽 车的电池负极，所述通信模块用于与所述电动汽车通信连接；
    所述处理器每次控制所述正极检测电阻和所述负极检测电阻中的任一个检测电阻连接的开关闭合，所述开关为所述第一开关和所述第二开关中的一个；
    在所述处理器每次控制所述开关闭合后，所述通信模块读取所述电动汽车反馈的针对所述检测电阻的测量阻值；
    所述处理器根据所述检测电阻的测量阻值和所述检测电阻的实际阻值，确定所述电动汽车针对所述检测电阻的测量偏差；
    所述处理器根据所述电动汽车针对所述检测电阻的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
  12. 一种诊断设备，包括直流总线、N个检测电阻群、设备地、处理器和通信模块；
    其中，N个所述检测电阻群一一对应于N个阻值区间，每个所述检测电阻群包括一个正极检测电阻和一个负极检测电阻，所述正极检测电阻通过第一开关连接所述直流总线的正极端和所述设备地，所述负极检测电阻通过第二开关连接所述直流总线的负极端和所述设备地，其中，N是大于或等于1的整数；
    所述直流总线的正极端用于连接电动汽车的电池正极，所述直流总线的负极端用于连接所述电动汽车的电池负极，所述通信模块用于分别与服务器和所述电动汽车通信连接；
    所述处理器每次控制所述正极检测电阻和所述负极检测电阻中的任一个检测电阻连接的开关闭合，所述开关为所述第一开关和所述第二开关中的一个；
    在所述处理器每次控制所述开关闭合后，所述通信模块读取所述电动汽车反馈的针对所述检测电阻的测量阻值；
    所述处理器根据所述检测电阻的测量阻值和所述检测电阻的实际阻值，确定所述电动汽车针对所述检测电阻的测量偏差；
    所述通信模块将所述测量偏差上传至所述服务器，以使所述服务器根据所述电动汽车针对所述检测电阻的至少一个测量偏差，确定所述电动汽车的绝缘检测功能正常或失效。
  13. 一种充电桩，包括如权利要求11或12所述的诊断设备。
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