Relay Fault Detection System, Method and Vehicle

Abstract

The present invention relates to the field of vehicles, and provides a relay fault detection system, a method and a vehicle. The system includes: a switching device, a current detection device and a controller; the switching device is connected between the branch relay of each battery branch and the branch negative electrode of each battery branch, and is used to conduct or cut off the path between the branch relay and the branch negative electrode; wherein, the branch relay is connected to the branch positive electrode of the battery branch; the current detection device is arranged at the branch negative electrode and is used to detect the current of the branch negative electrode; the current detection device corresponds to the branch negative electrode one by one; the controller is respectively connected to the branch relay, the switching device and the current detection device, and is used to perform switching control on the branch relay and the switching device, and perform fault detection on the branch relay according to the current of each branch negative electrode. The present invention effectively avoids the defect of poor reliability of the high-voltage relay fault detection using an auxiliary contact, and thus ensures the high-voltage safety of the whole vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicles, and particularly to a relay fault detection system, method and vehicle. Background Art

[0002] In recent years, with the further development of electrification, the application of multi-branch power battery systems in electric vehicles such as construction machinery and electric heavy trucks has become increasingly widespread. As the power output source of electric vehicles, once the high-voltage safety monitoring gets out of control, it will seriously affect the safety of the whole vehicle. Therefore, higher requirements are put forward for the safety and reliability of high-voltage diagnosis of multi-branch power battery systems. And the high-voltage relay, as a key component for controlling the high-voltage part of the power battery, the real-time, accurate and reliable detection of its faults is crucial for realizing the high-voltage safety of the whole vehicle.

[0003] In the design of existing multi-branch power battery systems, high-voltage relays with auxiliary contacts are usually adopted on each branch, and the high-voltage states of the relays on each branch are monitored through the auxiliary contacts to realize the fault detection of the relays. However, at present, the relays with auxiliary contacts all adopt the design method of microswitches, which have low reliability and are easy to be damaged, thus easily causing misdetection of high-voltage relay faults; if high-voltage relays without auxiliary contacts are not used, the current voltage comparison method cannot accurately diagnose the states of the high-voltage relays on each branch at present, seriously affecting the high-voltage safety of the whole vehicle. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a relay fault detection system, method and vehicle.

[0005] The present invention provides a relay fault detection system, including: a switching device, a current detection device and a controller;

[0006] The switching device is connected between the branch relay of each battery branch and the branch negative electrode of each battery branch, and is used to conduct or disconnect the path between the branch relay and the branch negative electrode; wherein, the branch relay corresponds to the battery branch one by one, and the branch relay is connected to the branch positive electrode of the battery branch;

[0007] The current detection device is arranged at the branch negative electrode and is used to detect the current of the branch negative electrode; the current detection device corresponds to the branch negative electrode one by one;

[0008] The controller is respectively connected to the branch relay, the switching device and the current detection device, and is used to perform switching control on the branch relay and the switching device, and perform fault detection on the branch relay according to the current of each branch negative electrode.

[0009] The relay fault detection system provided by the present invention further includes:

[0010] A first voltage detection device disposed at one end of the heating negative relay and a second voltage detection device disposed at the other end of the heating negative relay; the first voltage detection device and the second voltage detection device are respectively used to detect the voltages at both ends of the heating negative relay;

[0011] Wherein, the heating negative relay is disposed in a heating branch, and the heating branch is connected in parallel with the switching device; the heating branch further includes a heating positive relay, the heating positive relay is connected to the branch relay, and the heating negative relay is connected to the branch negative electrode;

[0012] The heating positive relay, the heating negative relay, the first voltage detection device, and the second voltage detection device are all connected to the controller, and the controller is further used to perform switching control on the heating positive relay and the heating negative relay, and perform fault detection on the heating positive relay and the heating negative relay according to the current at the branch negative electrode and the voltages at both ends of the heating negative relay.

[0013] The present invention also provides a relay fault detection method based on the relay fault detection system as described in any one of the above, including:

[0014] Controlling the switching device to close, and controlling each of the branch relays to be disconnected / closed;

[0015] Obtaining the first current at each branch negative electrode, and determining the fault detection result of each branch relay based on the first current at each branch negative electrode.

[0016] According to the relay fault detection method provided by the present invention, determining the fault detection result of each branch relay based on the first current at each branch negative electrode includes:

[0017] Based on the states of the branch relays, respectively comparing the first currents at the branch negative electrodes with a first preset current value or a second preset current value; wherein, the state of the branch relay is disconnected or closed;

[0018] Based on the comparison result of the first current at the branch negative electrode with the first preset current value or the second preset current value, determining the fault detection result of the branch relay.

[0019] According to the relay fault detection method provided by the present invention, it further includes:

[0020] Based on the fault detection results of each of the branch relays, when it is determined that each of the branch relays is free of faults, control the switch device to disconnect, and control the heating positive relay, the heating negative relay, and the branch relays to close or disconnect;

[0021] Obtain the voltage across the heating negative relay and the second current of each branch negative terminal, determine the fault detection result of the heating negative relay based on the voltage across the heating negative relay, and determine the fault detection result of the heating positive relay based on the second current of each branch negative terminal.

[0022] According to the relay fault detection method provided by the present invention, the determining the fault detection result of the heating negative relay based on the voltage across the heating negative relay includes:

[0023] Based on the state of the heating negative relay, compare the voltage across the heating negative relay with a first preset voltage value or a second preset voltage value; wherein, the state of the heating negative relay is open or closed; the voltage across the heating negative relay is collected when the heating positive relay is open;

[0024] Based on the comparison result of the voltage across the heating negative relay with the first preset voltage value or the second preset voltage value, determine the fault detection result of the heating negative relay.

[0025] According to the relay fault detection method provided by the present invention, the determining the fault detection result of the heating positive relay based on the second current of each branch negative terminal includes:

[0026] Based on the state of the heating positive relay, compare the sum of the second currents of each branch negative terminal with a third preset current value or a fourth preset current value; wherein, the state of the heating positive relay is open or closed; the second currents of each branch negative terminal are collected when the heating negative relay is free of faults and the heating negative relay is closed and at least one of the branch relays is closed;

[0027] Based on the comparison result of the sum of the second currents of each branch negative terminal with the third preset current value or the fourth preset current value, determine the fault detection result of the branch relay.

[0028] The present invention also provides a vehicle, including: a multi-branch battery system and the relay fault detection system as described in any one of the above.

[0029] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the program, the relay fault detection method as described in any one of the above is implemented.

[0030] The present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the relay fault detection method described in any one of the above is implemented.

[0031] The relay fault detection system, method and vehicle provided by the present invention set a switching device between the branch relay of each battery branch and the branch negative electrode of each battery branch, so as to conduct or cut off the path between the branch relay and the branch negative electrode through the switching device, and a current detection device is arranged on each branch negative electrode. Therefore, the controller can perform switching control on each branch relay and the switching device, and can accurately detect the faults of each branch relay according to the current of each branch negative electrode, avoiding the defect of poor reliability of the high-voltage relay fault detection with auxiliary contacts, and further ensuring the high-voltage safety of the whole vehicle. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0033] Figure 1 is one of the structural schematic diagrams of the relay fault detection system provided by the present invention;

[0034] Figure 2 is the second structural schematic diagram of the relay fault detection system provided by the present invention;

[0035] Figure 3 is the third structural schematic diagram of the relay fault detection system provided by the present invention;

[0036] Figure 4 is the flow schematic diagram of the adhesion fault detection of each branch relay provided by the present invention;

[0037] Figure 5 is the flow schematic diagram of the open circuit fault detection of each branch relay provided by the present invention;

[0038] Figure 6 is the flow schematic diagram of the adhesion fault detection of the heat negative relay and the heating positive relay provided by the present invention;

[0039] Figure 7 is the flow schematic diagram of the open circuit fault detection of the heat negative relay and the heating positive relay provided by the present invention;

[0040] Figure 8 is the structural schematic diagram of the electronic device provided by the present invention. Specific Embodiments

[0041] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present invention fall within the protection scope of the present invention.

[0042] The following will be combined with Figures 1 to 2 to describe the relay fault detection system of the present invention. The relay fault detection system of the present invention is used to detect faults of high-voltage relays in a multi-branch power battery system of an electric vehicle. As Figure 1 shown, the relay fault detection system of the present invention includes: a switching device 101, a current detection device 102, and a controller 103;

[0043] The switching device 101 is connected between the branch relay 104 of each battery branch and the branch negative electrode 105 of each battery branch, and is used to conduct or disconnect the path between the branch relay 104 and the branch negative electrode 105; wherein, the branch relay 104 corresponds to the battery branch one by one, and the branch relay 104 is connected to the branch positive electrode of the battery branch;

[0044] The current detection device 102 is arranged at the branch negative electrode 105 and is used to detect the current of the branch negative electrode 105; the current detection device 102 corresponds to the branch negative electrode 105 one by one;

[0045] The controller 103 is respectively connected to the branch relay 104, the switching device 101, and the current detection device 102, and is used to perform switching control on the branch relay 104 and the switching device 101, and perform fault detection on the branch relay 104 according to the current of each branch negative electrode 105.

[0046] Specifically, the branch relay 104 is connected to each battery branch, and each battery branch is connected with a branch relay 104. The branch relay 104 is connected to the branch positive electrode of the battery branch. The electric energy of the power battery pack 106 in the battery branch is transmitted to the main circuit through the branch relay 104, so as to transmit the electric energy in each battery branch to the load 109 through the main circuit. Wherein, one end of the branch positive electrode is connected to the positive electrode of the power battery pack 106 in the battery branch, and the other end is connected to the main circuit positive electrode 107, that is, the branch relay 104 is connected to the positive electrode of the power battery pack 106 through the branch positive electrode; one end of the branch negative electrode 105 is connected to the negative electrode of the power battery pack 106 in the battery branch, and the other end is connected to the main circuit negative electrode 108.

[0047] The switch device 101 is connected between the branch relay 104 of each battery branch and the branch negative electrode 105 of each battery branch, and may include a switching device. When the switching device is closed, the path between the branch relay 104 and the branch negative electrode 105 is conducted. When the switching device is open, the path between the branch relay 104 and the branch negative electrode 105 is disconnected. The switching device may be a reed switch, an electromagnetic switch, etc., and can be specifically set according to actual requirements. At the same time, the switch device 101 may further include a protection resistor to prevent damage to the power battery pack 106 when the branch positive electrode is connected to the branch negative electrode 105. The size of the protection resistor can be set according to actual requirements. For example, it can be a resistor in the order of kiloohms. The protection resistor can be a single resistor or a series-parallel combination of multiple resistors.

[0048] The current detection device 102 is provided at the branch negative electrode 105, and each branch negative electrode 105 is connected with a current detection device 102, so that the current of the corresponding branch negative electrode 105 can be detected through the current detection device 102. The specific type of the current detection device 102 can be set according to actual requirements. For example, it can be a current sensor.

[0049] The controller 103 can be the controller 103 of the vehicle itself. For example, BMU (Battery Management Unit), or can also be a newly added controller, which can be specifically set according to actual requirements. The controller 103 is respectively signal-connected to each branch relay 104, the switch device 101, and the current detection device 102 ( Figure 1 the connection relationship of the controller 103 is omitted in the figure), and is used for performing switch control on each branch relay 104 and the switch device 101, and performing fault detection on each branch relay 104 according to the current detected by each current detection device 102. It can be understood that the controller 103 can also be used to control the opening and closing of the current detection device 102, so as to control the current detection device 102 to open when current detection is required, and close the current detection device 102 after the current detection is completed.

[0050] When it is detected that the branch relay 104 has no fault, the fault detection result can be no fault. When it is detected that the branch relay 104 has a fault, the fault detection result can be a specific fault type, such as adhesion, open circuit.

[0051] Among them, the specific method for fault detection of each branch relay 104 can be set according to actual needs. For example, when the path between the branch relay 104 and the branch negative electrode 105 is conducting, the fault of the branch relay 104 and the specific fault type can be determined according to the magnitude of the current of the corresponding branch negative electrode 105 when the branch relay 104 is in different states.

[0052] As an alternative implementation, the controller 103 is specifically configured to:

[0053] Control the switch device 101 to close, and control each of the branch relays 104 to open / close;

[0054] Obtain the first current of each branch negative electrode 105, and determine the fault detection result of each branch relay 104 based on the first current of each branch negative electrode 105.

[0055] Specifically, control the switch device 101 to close to conduct the path between the branch relay 104 and the branch negative electrode 105, that is, each battery branch forms a loop, and the current of the branch negative electrode 105 indicates the current in the corresponding loop. Therefore, according to the first current of the branch negative electrode 105, the fault detection result of the corresponding branch relay 104 can be determined. Among them, the first current of the branch negative electrode 105 is the current of the corresponding branch negative electrode 105 detected by the current detection device 102 when the switch device 101 is closed and each branch relay 104 is open / closed.

[0056] Among them, the specific method for determining the fault detection result of each branch relay 104 based on the first current of each branch negative electrode 105 can be set according to actual needs. For example, it may include:

[0057] Based on the states of the branch relays 104, compare the first current of each branch negative electrode 105 with a first preset current value or a second preset current value respectively; where the state of the branch relay 104 is open or closed;

[0058] Based on the comparison result of the first current of the branch negative electrode 105 with the first preset current value or the second preset current value, determine the fault detection result of the branch relay 104.

[0059] Specifically, when the state of the branch relay 104 is open, if the difference between the first current of the branch negative electrode 105 in the corresponding battery branch and the first preset current value is less than or equal to the first current difference and lasts for the first preset duration, it indicates that the branch relay 104 has an adhesion fault; otherwise, it indicates that the branch relay 104 has no adhesion fault. Among them, the magnitude of the first preset current value can be set according to actual needs. For example, the first preset current value can be U / R, where U is the real-time output voltage of the power battery pack 106 in the battery branch, and R is the resistance value of the protection resistor in the switching device 101; the first current difference and the first preset duration can be set according to actual accuracy. For example, the first preset duration can be set to 5000 ms.

[0060] When the state of the branch relay 104 is closed, if the difference between the first current of the branch negative electrode 105 in the corresponding battery branch and the second preset current value is less than or equal to the second current difference and lasts for the second preset duration, it indicates that the branch relay 104 has an open circuit fault; otherwise, it indicates that the branch relay 104 has no open circuit fault. Among them, the magnitude of the second preset current value can be set according to actual needs. For example, the second preset current value can be 0; the second current difference and the second preset duration can be set according to actual accuracy. For example, the second preset duration can be set to 5000 ms. When it is determined that the branch relay 104 has no adhesion fault and no open circuit fault at the same time, that is, it is determined that the fault detection result of the branch relay 104 is no fault.

[0061] By controlling the switching device 101 to close and controlling each branch relay 104 to open / close, and obtaining the current of each branch negative electrode 105, according to the current of each branch negative electrode 105, the fault detection result of the corresponding branch relay 104 can be determined, so as to obtain the fault detection result of each branch relay 104. Without using a high-voltage relay with auxiliary contacts, the fault detection of each branch relay 104 can be realized. The detection process is simple and efficient, and the reliability of the fault detection result can be effectively guaranteed. After the fault detection is completed, control the switching device 101 to open to disconnect the path between the branch relay 104 and the branch negative electrode 105, so as to avoid affecting the power supply to the load 109.

[0062] The controller 103 can report the fault detection results of each branch relay 104 to the BMS (Battery Management System) so that when a fault occurs, the BMS can restrict the multi-branch power battery system according to relevant strategies to ensure the high-voltage safety of the vehicle. For example, prohibit the vehicle from high-voltage power-on and send a warning message.

[0063] As another alternative implementation, fault detection can be performed on each branch relay 104 when the vehicle is powered on at low voltage. For example, when the vehicle is powered on at low voltage and the timer has counted for a first duration, fault detection can be performed on each branch relay 104. The first duration can be set according to the specific performance of the vehicle. For example, it can be set to 1000 ms to ensure the stability of the operation of the corresponding vehicle components.

[0064] As yet another alternative implementation, before performing fault detection on each branch relay 104, the insulation detection function of the vehicle can also be controlled to be turned off to prevent interference with the detection result of the current signal. At the same time, after the fault detection of each branch relay 104 is completed, the insulation detection function of the vehicle is controlled to be turned on.

[0065] It should be noted that when performing fault detection on each branch relay 104, the main circuit relay needs to be controlled to disconnect to avoid the influence of the main circuit supplying power to the load 109 on the current of the branch negative electrode 105.

[0066] In the embodiment of the present invention, a switching device 101 is provided between the branch relay 104 of each battery branch and the branch negative electrode 105 of each battery branch, so as to conduct or disconnect the path between the branch relay 104 and the branch negative electrode 105 through the switching device 101, and a current detection device 102 is provided on each branch negative electrode 105. Thus, the controller 103 performs switching control on each branch relay 104 and the switching device 101, and can accurately perform fault detection on each branch relay 104 according to the current of each branch negative electrode 105, avoiding the defect of poor reliability of fault detection of a high-voltage relay with auxiliary contacts, and further ensuring the high-voltage safety of the whole vehicle.

[0067] In addition, the range of selection of existing relay products with auxiliary contacts is small, and it is impossible to achieve compatibility of multiple relay models in the design of a multi-branch power battery system. However, in the embodiment of the present invention, fault detection is performed on each branch relay 104 according to the current of each branch negative electrode 105, and there is no requirement for the relay model, so that compatibility of multiple relay models can be achieved in the design of a multi-branch power battery system.

[0068] Based on the above embodiments, as Figure 2 shown, it further includes:

[0069] A first voltage detection device 201 provided at one end of the heating negative relay 203 and a second voltage detection device 202 provided at the other end of the heating negative relay 203; the first voltage detection device 201 and the second voltage detection device 202 are respectively used to detect the voltages at both ends of the heating negative relay 203;

[0070] Among them, the heating negative relay 203 is arranged in the heating branch, and the heating branch is connected in parallel with the switching device 101; the heating branch further includes a heating positive relay 204, the heating positive relay 204 is connected to the branch relay 104, and the heating negative relay 203 is connected to the branch negative electrode 105;

[0071] The heating positive relay 204, the heating negative relay 203, the first voltage detection device 201 and the second voltage detection device 202 are all connected to the controller 103. The controller 103 is further configured to perform switching control on the heating positive relay 204 and the heating negative relay 203, and perform fault detection on the heating positive relay 204 and the heating negative relay 203 according to the current of the branch negative electrode 105 and the voltage across the heating negative relay 203.

[0072] Specifically, the heating branch is used to heat the power battery packs 106 in each battery branch to ensure the working performance of the power battery packs 106 in a cold environment. The heating branch is connected in parallel with the switching device 101, that is, electrical energy is provided for the heating branch through the power battery packs 106 in each battery branch. The heating branch includes a heating positive relay 204, a heating negative relay 203 and a heating component 205. The heating positive relay 204 and the heating negative relay 203 are used to control the conduction and disconnection of the heating branch. When the heating branch is conducting, the heating component 205 is powered on and heats the power battery pack 106. When the heating branch is disconnected, the heating component 205 is powered off and stops heating the power battery pack 106. The heating component 205 may include a plurality of parallel-connected battery heating films, and the plurality of parallel-connected battery heating films are respectively used to heat the power battery packs 106 in different battery branches. Among them, the heating positive relay 204 is connected to the branch relay 104, that is, the heating positive relay 204 is connected to the branch positive electrode through the branch relay 104, and the heating negative relay 203 is connected to the branch negative electrode 105.

[0073] The relay fault detection system further includes a first voltage detection device 201 and a second voltage detection device 202 respectively arranged at both ends of the heating negative relay 203. Among them, one end of the first voltage detection device 201 and the second voltage detection device 202 are both connected to the heating negative relay 203, and the other end of the first voltage detection device 201 and the second voltage detection device 202 are both grounded, so as to collect the voltage at one end of the heating negative relay 203 through the first voltage detection device 201 and collect the voltage at the other end of the heating negative relay 203 through the second voltage detection device 202. The specific types of the first voltage detection device 201 and the second voltage detection device 202 can be set according to actual needs. For example, a voltage sensor can be used.

[0074] The heating positive relay 204, the heating negative relay 203, the first voltage detection device 201, and the second voltage detection device 202 are all signal - connected to the controller 103 ( Figure 2 the connection relationship of the controller 103 is omitted), and the controller 103 is further configured to perform on - off control on the heating positive relay 204 and the heating negative relay 203, and perform fault detection on the heating positive relay 204 and the heating negative relay 203 according to the current detected by each current detection device 102 and the voltage detected by the first voltage detection device 201 and the second voltage detection device 202. It can be understood that the controller 103 can also control the on - off of the first voltage detection device 201 and the second voltage detection device 202, so as to control the first voltage detection device 201 and the second voltage detection device 202 to turn on when voltage detection is required, and turn off the first voltage detection device 201 and the second voltage detection device 202 after the voltage detection is completed.

[0075] Among them, the specific method for performing fault detection on the heating positive relay 204 and the heating negative relay 203 can be set according to actual needs. For example, when the path between the branch relay 104 and the branch negative electrode 105 is disconnected, fault detection can be performed on the heating positive relay 204 and the heating negative relay 203 according to the voltage across the heating negative relay 203 and the current in the heating branch when each branch relay 104, the heating positive relay 204, and the heating negative relay 203 are in different states; the current in the heating branch can be determined by the sum of the currents of each branch negative electrode 105.

[0076] As an optional implementation manner, the controller 103 is specifically configured to:

[0077] Based on the fault detection results of each branch relay 104, when it is determined that each branch relay 104 has no fault, control the switch device 101 to disconnect, and control the heating positive relay 204, the heating negative relay 203, and the branch relay 104 to close or disconnect;

[0078] Obtain the voltage across the heating negative relay 203 and the second current of each branch negative electrode 105, determine the fault detection result of the heating negative relay 203 based on the voltage across the heating negative relay 203, and determine the fault detection result of the heating positive relay 204 based on the second current of each branch negative electrode 105.

[0079] Specifically, when it is determined that each branch relay 104 has no fault based on the fault detection results of each branch relay 104, fault detection can also be performed on the heating positive relay 204 and the heating negative relay 203.

[0080] During the process of fault detection for the heating positive relay 204 and the heating negative relay 203, the switch device 101 can be controlled to disconnect, so as to cut off the path between the branch relay 104 and the branch negative electrode 105, and the power battery pack 106 is used to supply power to the heating branch.

[0081] When the heating negative relay 203 is closed or open, the fault detection result of the heating negative relay 203 can be determined according to the voltage difference across the heating negative relay 203. When the heating negative relay 203 is fault-free, the heating negative relay 203 can be further closed. When at least one branch relay 104 is closed, the heating positive relay 204 is controlled to be closed or open, and the fault detection result of the heating positive relay 204 is determined according to the magnitude of the second current of each branch negative electrode 105, so that the fault detection can be carried out on the heating positive relay 204 and the heating negative relay 203 respectively, further ensuring the safety during the power battery heating process, and the detection process is simple and efficient.

[0082] It should be noted that when fault detection is carried out on the heating positive relay 204, the main circuit relay needs to be controlled to disconnect to avoid the influence of the main circuit supplying power to the load 109 on the current of the branch negative electrode 105.

[0083] Wherein, the controller 103 determines the fault detection result of the heating negative relay 203 based on the voltage across the heating negative relay 203, including:

[0084] Based on the state of the heating negative relay 203, the voltage across the heating negative relay 203 is compared with a first preset voltage value or a second preset voltage value; wherein, the state of the heating negative relay 203 is open or closed; the voltage across the heating negative relay 203 is collected when the heating positive relay 204 is open;

[0085] Based on the comparison result of the voltage across the heating negative relay 203 with the first preset voltage value or the second preset voltage value, the fault detection result of the heating negative relay 203 is determined.

[0086] Specifically, when it is determined that each branch relay 104 is fault-free, the switch device 101 and the heating positive relay 204 are both controlled to disconnect, so that when the state of the heating negative relay 203 is closed / open, the fault detection result of the heating negative relay 203 is determined according to the voltage across the heating negative relay 203.

[0087] When the state of the heating negative relay 203 is open, if the voltage difference across the heating negative relay 203 is less than or equal to the first preset voltage value and lasts for the third preset duration, it indicates that the heating negative relay 203 has an adhesion fault; otherwise, it indicates that the heating negative relay 203 has no adhesion fault. Among them, the magnitude of the first preset voltage value can be set according to actual needs. For example, it can be set to 5% of the voltage value at the position of the branch negative electrode 105; the third preset duration can be set according to actual accuracy. For example, the third preset duration can be set to 5000 ms.

[0088] When the state of the heating negative relay 203 is closed, if the voltage difference across the heating negative relay 203 is greater than or equal to the second preset voltage value and lasts for the fourth preset duration, it indicates that the heating negative relay 203 has an open circuit fault; otherwise, it indicates that the heating negative relay 203 has no open circuit fault. Among them, the magnitude of the second preset voltage value can be set according to actual needs. For example, it can be set to 20% of the voltage value at the position of the branch negative electrode 105; the fourth preset duration can be set according to actual accuracy. For example, the fourth preset duration can be set to 5000 ms. When it is determined that the heating negative relay 203 has no adhesion fault and no open circuit fault at the same time, that is, it is determined that the fault detection result of the heating negative relay 203 is no fault.

[0089] The controller 103 determines the fault detection result of the heating positive relay 204 based on the second current of each branch negative electrode 105, including:

[0090] Based on the state of the heating positive relay 204, compare the sum of the second currents of each branch negative electrode 105 with the third preset current value or the fourth preset current value; among them, the state of the heating positive relay 204 is open or closed; the second currents of each branch negative electrode 105 are collected when the heating negative relay 203 has no fault and the heating negative relay 203 is closed and at least one of the branch relays 104 is closed;

[0091] Based on the comparison result of the sum of the second currents of each branch negative electrode 105 and the third preset current value or the fourth preset current value, determine the fault detection result of the branch relay 104.

[0092] Specifically, when it is determined that the heating negative relay 203 has no fault, the heating negative relay 203 can be further controlled to close, and at the same time, at least one branch relay 104 is controlled to close, so as to supply electrical energy to the heating branch through the power battery pack 106, so that when the state of the heating positive relay 204 is closed / open, the fault detection result of the heating positive relay 204 is determined according to the second current of each branch negative electrode 105.

[0093] When the state of the positive heating relay 204 is open, if the difference between the sum of the second currents of the negative electrodes 105 of each branch and the third preset current value is less than or equal to the third current difference and lasts for the fifth preset duration, it indicates that the positive heating relay 204 has an adhesion fault; otherwise, it indicates that the positive heating relay 204 has no adhesion fault. Among them, the magnitude of the third preset current value can be set according to actual requirements. For example, the third preset current value can be U / R′, where R′ is the resistance value of the heating component 205; the third current difference and the fifth preset duration can be set according to actual accuracy. For example, the fifth preset duration can be set to 5000 ms.

[0094] When the state of the positive heating relay 204 is closed, if the difference between the sum of the second currents of the negative electrodes 105 of each branch and the fourth preset current value is less than or equal to the fourth current difference and lasts for the sixth preset duration, it indicates that the positive heating relay 204 has an open - circuit fault; otherwise, it indicates that the positive heating relay 204 has no open - circuit fault. Among them, the magnitude of the fourth preset current value can be set according to actual requirements. For example, the fourth preset current value can be 0; the fourth current difference and the sixth preset duration can be set according to actual accuracy. For example, the sixth preset duration can be set to 5000 ms. When it is determined that the positive heating relay 204 has neither an adhesion fault nor an open - circuit fault, that is, when the fault detection result of the positive heating relay 204 is determined to be no fault, the fault detection results of the negative heating relay 203 and the positive heating relay 204 are obtained.

[0095] By collecting the voltage across the negative heating relay 203 when the positive heating relay 204 is open, determining the fault detection result of the negative heating relay 203 based on the comparison result between the voltage across the negative heating relay 203 and the first preset voltage value or the second preset voltage value, and closing the negative heating relay 203 and at least one branch relay 104 when the negative heating relay 203 has no fault, collecting the second current of each branch negative electrode 105, and determining the fault detection result of the branch relay 104 based on the comparison result between the sum of the second currents of each branch negative electrode 105 and the third preset current value or the fourth preset current value, the fault detection results of the negative heating relay 203 and the positive heating relay 204 are obtained. It can realize the fault detection of the positive heating relay 204 and the negative heating relay 203 without using a high - voltage relay with auxiliary contacts. The fault detection process is simple and efficient, and effectively ensures the reliability of the fault detection result.

[0096] The controller 103 can report the fault detection results of the negative heating relay 203 and the positive heating relay 204 to the BMS, so that when a fault occurs, the BMS can restrict the multi - branch power battery system according to relevant strategies to ensure the safety during the power battery heating process. For example, prohibit the vehicle from heating the power battery pack 106 and send a warning message.

[0097] As an alternative implementation, fault detection can be performed on the heating negative relay 203 and the heating positive relay 204 when the vehicle is powered on at low voltage. For example, when the vehicle is powered on at low voltage and the timer meets the second duration, fault detection can be performed on the heating negative relay 203 and the heating positive relay 204. The second duration can be set according to the specific performance of the vehicle and the fault detection duration of each branch relay 104. For example, it can be set to 5000 ms to ensure the effectiveness of the fault detection result.

[0098] As another alternative implementation, before performing fault detection on the heating negative relay 203 and the heating positive relay 204, the insulation detection function of the vehicle can also be controlled to be turned off to prevent interference with the detection results of current signals and voltage signals. At the same time, after the fault detection of the heating negative relay 203 and the heating positive relay 204 is completed, the insulation detection function of the vehicle is controlled to be turned on.

[0099] In the embodiment of the present invention, a first voltage detection device 201 and a second voltage detection device 202 are respectively arranged at both ends of the heating negative relay 203. Thus, the controller 103 can perform switching control on each branch relay 104, the switching device 101, the heating positive relay 204, and the heating negative relay 203, and can perform fault detection on the heating positive relay 204 and the heating negative relay 203 according to the current of each branch negative electrode 105 and the voltage across the heating negative relay 203, avoiding the defect of poor reliability of fault detection using a high-voltage relay with auxiliary contacts, and further ensuring the safety during the heating process of the power battery.

[0100] The relay fault detection method provided by the present invention will be described below. The relay fault detection method described below can be correspondingly referred to the relay fault detection system described above. That is, the relay fault detection method in the embodiment of the present invention is implemented based on the relay fault detection system described in any of the above embodiments. The relay fault detection method in the embodiment of the present invention is executed by the controller 103 and includes:

[0101] Control the switching device 101 to close, and control each branch relay 104 to open / close;

[0102] Obtain the first current of each branch negative electrode 105, and determine the fault detection result of each branch relay 104 based on the first current of each branch negative electrode 105.

[0103] Based on the above embodiment, the determining the fault detection result of each branch relay 104 based on the first current of each branch negative electrode 105 includes:

[0104] Based on the states of the branch relays 104, compare the first current of each branch negative electrode 105 with a first preset current value or a second preset current value respectively; wherein, the state of the branch relay 104 is open or closed;

[0105] Based on the comparison result of the first current of the branch negative electrode 105 with the first preset current value or the second preset current value, determine the fault detection result of the branch relay 104.

[0106] Based on any of the above embodiments, the relay fault detection method further includes:

[0107] Based on the fault detection results of the branch relays 104, when it is determined that the branch relays 104 are free of faults, control the switch device 101 to open, and control the heating positive relay 204, the heating negative relay 203 and the branch relays 104 to close or open;

[0108] Obtain the voltage across the heating negative relay 203 and the second current of each branch negative electrode 105, determine the fault detection result of the heating negative relay 203 based on the voltage across the heating negative relay 203, and determine the fault detection result of the heating positive relay 204 based on the second current of each branch negative electrode 105.

[0109] Based on any of the above embodiments, the determining the fault detection result of the heating negative relay 203 based on the voltage across the heating negative relay 203 includes:

[0110] Based on the state of the heating negative relay 203, compare the voltage across the heating negative relay 203 with a first preset voltage value or a second preset voltage value; wherein, the state of the heating negative relay 203 is open or closed; the voltage across the heating negative relay 203 is collected when the heating positive relay 204 is open;

[0111] Based on the comparison result of the voltage across the heating negative relay 203 with the first preset voltage value or the second preset voltage value, determine the fault detection result of the heating negative relay 203.

[0112] Based on any of the above embodiments, the determining the fault detection result of the heating positive relay 204 based on the second current of each branch negative electrode 105 includes:

[0113] Based on the state of the heating positive relay 204, compare the sum of the second currents of the negative electrodes 105 of each branch with a third preset current value or a fourth preset current value; wherein, the state of the heating positive relay 204 is open or closed; the second currents of the negative electrodes 105 of each branch are collected when the heating negative relay 203 is free of faults, the heating negative relay 203 is closed, and at least one branch relay 104 is closed;

[0114] Based on the comparison result between the sum of the second currents of the negative electrodes 105 of each branch and the third preset current value or the fourth preset current value, determine the fault detection result of the branch relay 104.

[0115] An embodiment of the present invention further provides a vehicle, including: a multi-branch battery system and the relay fault detection system according to any one of the above embodiments.

[0116] Specifically, the vehicle is an electric vehicle such as an electric construction machinery or an electric heavy truck.

[0117] The implementation process of the relay fault detection method of the present invention is described in detail below through an optional implementation manner.

[0118] The structural schematic diagram of the relay fault detection system is as Figure 3 shown. Among them, the switching device 101 includes a first resistor 301, a first switch 302, a second switch 303, and a second resistor 304 connected in series in sequence. A ground connection is provided between the first switch 302 and the second switch 303, and both the first voltage detection device 201 and the second voltage detection device 202 are connected to this ground connection point. Among them, both the first resistor 301 and the second resistor 304 are resistors in the order of kilo-ohms.

[0119] The flow schematic diagram for detecting the sticking fault of each branch relay 104 is as Figure 4 shown, including:

[0120] S401. Initialize the power-on at a low voltage and start timing with a timer. When it is determined that the timing duration reaches 1000 ms, execute step S402;

[0121] S402. Do not enable the low-voltage control opening of each branch relay 104; that is, control each branch relay 104 to be disconnected;

[0122] S403. Turn off the insulation detection and enable the first switch 302 and the second switch 303 to be closed;

[0123] S404. Enable each current detection device 102 in sequence, and collect the first current of each branch negative electrode 105 through each current detection device 102; determine whether the first current of each branch negative electrode 105 is U / (R1 + R2) and lasts for 5000 ms. If not, execute step S405; if so, execute step S406; where R1 and R2 are the resistance values of the first resistor 301 and the second resistor 304 respectively.

[0124] S405. The adhesion detection of the branch relay 104 is completed, and no adhesion fault occurs. Execute step S407.

[0125] S406. The branch relay 104 has an adhesion fault and reports the fault to the BMS.

[0126] S407. Disconnect the first switch 302 and the second switch 303, and enable the insulation detection function to be turned on.

[0127] The flow diagram for the open - circuit fault detection of each branch relay 104 is as Figure 5 shown, including:

[0128] S501. Power on low - voltage and initialize, and start timing through a timer. When the timing duration reaches 1000 ms, execute step S502.

[0129] S502. Enable the low - voltage control of each branch relay 104 to be turned on; that is, control each branch relay 104 to be closed.

[0130] S503. Turn off the insulation detection, and enable the first switch 302 and the second switch 303 to be closed.

[0131] S504. Enable each current detection device 102 in sequence, and collect the first current of each branch negative electrode 105 through each current detection device 102; determine whether the first current of each branch negative electrode 105 is 0 and lasts for 5000 ms. If not, execute step S505; if so, execute step S506.

[0132] S505. The open - circuit detection of the branch relay 104 is completed, and no open - circuit fault occurs. Execute step S507.

[0133] S506. The branch relay 104 has an open - circuit fault and reports the fault to the BMS.

[0134] S507. Disconnect the first switch 302 and the second switch 303, and enable the insulation detection function to be turned on.

[0135] The flow diagram for the adhesion fault detection of the heating negative relay 203 and the heating positive relay 204 is as Figure 6 shown, including:

[0136] S601. Low-voltage power-on initialization. When it is determined that each branch relay 104 has no fault and the timing duration of the timer reaches 5000 ms, step S602 is executed;

[0137] S602. Do not enable the low-voltage control to turn on the heating positive relay 204 and the heating negative relay 203; that is, control both the heating positive relay 204 and the heating negative relay 203 to be disconnected;

[0138] S603. Enable the first voltage detection device 201 and the second voltage detection device 202 to respectively collect the voltage across the heating negative relay 203;

[0139] S604. Calculate the voltage difference across the heating negative relay 203, and compare the voltage difference with the first preset voltage value; determine whether the voltage difference is less than or equal to the first preset voltage value and lasts for 5000 ms. If yes, step S605 is executed; if no, step S606 is executed;

[0140] S605. The heating negative relay 203 has an adhesion fault, report the fault to the BMS, and execute step S609;

[0141] S606. Enable the heating negative relay 203 and at least one branch relay 104 for low-voltage control to turn on;

[0142] S607. Enable each current detection device 102 to collect the second current of each branch negative electrode 105, and calculate the sum of the second currents of each branch negative electrode 105; determine whether the sum of the second currents is U / R' and lasts for 5000 ms. If yes, step S608 is executed; if no, step S609 is executed;

[0143] S608. The heating positive relay 204 has an adhesion fault, report the fault to the BMS, and execute step S609;

[0144] S609. The detection of the adhesion fault of the heating branch relay 104 is completed.

[0145] The flow chart for detecting the open circuit faults of the heating negative relay 203 and the heating positive relay 204 is as Figure 7 shown, including:

[0146] S701. Low-voltage power-on initialization. When it is determined that each branch relay 104 has no fault and the timing duration of the timer reaches 5000 ms, step S702 is executed;

[0147] S702. Enable the low-voltage control to turn on the heating negative relay 203, and do not enable the low-voltage control to turn on the heating positive relay 204; that is, control the heating negative relay 203 to be closed, and control the heating positive relay 204 to be disconnected;

[0148] S703. Enable the first voltage detection device 201 and the second voltage detection device 202 to collect the voltages across the heating negative relay 203 respectively;

[0149] S704. Calculate the difference between the voltages across the heating negative relay 203, and compare the voltage difference with a second preset voltage value; Determine whether the voltage difference is greater than or equal to the second preset voltage value and lasts for 5000 ms. If yes, execute step S705; if no, execute step S706;

[0150] S705. There is an open - circuit fault in the heating negative relay 203, report the fault to the BMS, and execute step S709;

[0151] S706. Enable the heating positive relay 204 and at least one branch relay 104 to be controlled to turn on at low voltage;

[0152] S707. Enable each current detection device 102 to collect the second current of each branch negative electrode 105, and calculate the sum of the second currents of each branch negative electrode 105; Determine whether the sum of the second currents is 0 and lasts for 5000 ms. If yes, execute step S708; if no, execute step S709;

[0153] S708. There is an open - circuit fault in the heating positive relay 204, report the fault to the BMS, and execute step S709;

[0154] S709. The open - circuit fault detection of the heating branch relay 104 is completed.

[0155] Figure 8 An entity structure diagram of an electronic device is exemplified. As Figure 8 shown, the electronic device may include: a processor 801, a communications interface 802, a memory 803, and a communication bus 804. Among them, the processor 801, the communications interface 802, and the memory 803 communicate with each other through the communication bus 804. The processor 801 can call the logical instructions in the memory 803 to execute the relay fault detection method, and the method includes: controlling the switch device 101 to close, and controlling each of the branch relays 104 to disconnect / connect;

[0156] Obtain the first current of each branch negative electrode 105, and determine the fault detection result of each branch relay 104 based on the first current of each branch negative electrode 105.

[0157] In addition, when the logical instructions in the above-mentioned memory 803 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

[0158] On the other hand, the present invention also provides a computer program product. The computer program product includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the relay fault detection method provided by the above-mentioned various methods. The method includes: controlling the switch device 101 to close, and controlling each of the branch relays 104 to open / close;

[0159] Obtaining the first current of each of the branch negative electrodes 105, and determining the fault detection result of each of the branch relays 104 based on the first current of each of the branch negative electrodes 105.

[0160] On another aspect, the present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it is configured to execute the relay fault detection method provided by the above-mentioned various methods. The method includes: controlling the switch device 101 to close, and controlling each of the branch relays 104 to open / close;

[0161] Obtaining the first current of each of the branch negative electrodes 105, and determining the fault detection result of each of the branch relays 104 based on the first current of each of the branch negative electrodes 105.

[0162] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative labor.

[0163] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0164] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A relay fault detection system, characterized in that, Including: A switching device, a current detection device, and a controller; The switching device is connected between the branch relay of each battery branch and the branch negative electrode of each battery branch, and is used to conduct or disconnect the path between the branch relay and the branch negative electrode; wherein, the branch relay corresponds to the battery branch one by one, and the branch relay is connected to the branch positive electrode of the battery branch; The current detection device is arranged at the branch negative electrode and is used to detect the current of the branch negative electrode; the current detection device corresponds to the branch negative electrode one by one; The controller is respectively connected to the branch relay, the switching device, and the current detection device, and is used to perform switching control on the branch relay and the switching device, and perform fault detection on the branch relay according to the second current of each branch negative electrode; The relay fault detection system further includes: a first voltage detection device arranged at one end of the heating negative relay and a second voltage detection device arranged at the other end of the heating negative relay; the first voltage detection device and the second voltage detection device are respectively used to detect the voltage across the heating negative relay; wherein, the heating negative relay is arranged in the heating branch, and the heating branch is connected in parallel with the switching device; the heating branch further includes a heating positive relay, the heating positive relay is connected to the branch relay, and the heating negative relay is connected to the branch negative electrode; the heating positive relay, the heating negative relay, the first voltage detection device, and the second voltage detection device are all connected to the controller, and the controller is further used to perform switching control on the heating positive relay and the heating negative relay, determine the fault detection result of the heating negative relay based on the voltage across the heating negative relay, and determine the fault detection result of the heating positive relay based on the second current of each branch negative electrode.

2. A relay fault detection method, characterized in that, Applied to the relay fault detection system according to claim 1, including: Controlling the switching device to close, and controlling each branch relay to disconnect / close; Obtaining the first current of each branch negative electrode, and determining the fault detection result of each branch relay based on the first current of each branch negative electrode; The relay fault detection method further includes: when it is determined that each branch relay has no fault based on the fault detection results of each branch relay, controlling the switching device to disconnect, and controlling the heating positive relay, the heating negative relay, and the branch relay to close or disconnect; obtaining the voltage across the heating negative relay and the second current of each branch negative electrode, determining the fault detection result of the heating negative relay based on the voltage across the heating negative relay, and determining the fault detection result of the heating positive relay based on the second current of each branch negative electrode.

3. The relay fault detection method according to claim 2, characterized in that, The determining the fault detection result of each branch relay based on the first current of each branch negative electrode includes: Based on the states of the respective branch relays, compare the first currents of the respective branch negatives with a first preset current value or a second preset current value; wherein, the states of the branch relays are open or closed; Based on the comparison result of the first current of the branch negative with the first preset current value or the second preset current value, determine the fault detection result of the branch relay.

4. The relay fault detection method according to claim 2, wherein, The determining the fault detection result of the heating negative relay based on the voltage across the heating negative relay includes: Based on the state of the heating negative relay, compare the voltage across the heating negative relay with a first preset voltage value or a second preset voltage value; wherein, the state of the heating negative relay is open or closed; the voltage across the heating negative relay is collected when the heating positive relay is open; Based on the comparison result of the voltage across the heating negative relay with the first preset voltage value or the second preset voltage value, determine the fault detection result of the heating negative relay.

5. The relay fault detection method according to claim 2, wherein The determining the fault detection result of the heating positive relay based on the second currents of the respective branch negatives includes: Based on the state of the heating positive relay, compare the sum of the second currents of the respective branch negatives with a third preset current value or a fourth preset current value; wherein, the state of the heating positive relay is open or closed; the second currents of the respective branch negatives are collected when the heating negative relay is fault-free and the heating negative relay is closed and at least one of the branch relays is closed; Based on the comparison result of the sum of the second currents of the respective branch negatives with the third preset current value or the fourth preset current value, determine the fault detection result of the branch relay.

6. A vehicle, characterized in that, including: A multi-branch battery system and the relay fault detection system according to claim 1.

7. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein, When the processor executes the program, the relay fault detection method according to any one of claims 2 to 5 is implemented.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the relay fault detection method according to any one of claims 2 to 5 is implemented.

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