Heating relay fault diagnosis method and device, electronic equipment and medium

Abstract

The invention provides a fault diagnosis method and device for a heating relay, electronic equipment and a readable storage medium. The relay fault diagnosis method comprises the steps that when charging preheating is started (at the moment, an insulation monitoring function is closed), a heating relay is controlled to be closed, and whether the heating relay is stuck and cannot be closed or not is diagnosed according to the voltage relation of all nodes in a charging preheating equivalent circuit. And when charging preheating is finished (at the moment, the insulation monitoring function is closed), the heating relay is controlled to be switched off, and whether the heating relay is stuck and cannot be switched on or not is diagnosed according to the voltage relation of the nodes in the charging preheating equivalent circuit. The negative influence of insulation monitoring can be avoided, and the reliability of a diagnosis result is remarkably improved; no hardware cost is added, and logic is simple and easy to implement.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a fault diagnosis method, device, electronic equipment and readable storage medium for a heating relay. Background Art

[0002] With the popularity of electric vehicles, the requirements for the working performance and safety of electric vehicles are getting higher and higher. In order to overcome the problem of low discharge power and limited charging power of batteries (unless otherwise specified, the batteries in this article refer to vehicle batteries) at low temperatures, it is often necessary to heat the batteries when starting or charging at low temperatures to raise the battery temperature to a reasonable range as soon as possible. For example, see Figure 1 , Figure 1 The topological structure diagram of a high-voltage sampling circuit in a battery management system is shown in FIG. Figure 1 As shown, most existing electric vehicles use a heating device (for example, Figure 1 The heating film resistor R0 in the charging preheating circuit generates heat to raise the battery temperature to a suitable range, and the heating device no longer generates heat by disconnecting the heating relay K1, thereby achieving reasonable control of the battery temperature. Therefore, whether from a functional consideration or a safety requirement, it is necessary to reasonably diagnose whether the heating relay K1 of the charging preheating circuit has a stuck close fault or a stuck open fault, and to promptly feedback its status so that the charging preheating circuit is in a correct working state.

[0003] like Figure 1 As shown, in the related art, when the main positive relay K2 and the main negative relay K3 are closed, the first node ( Figure 1 The first voltage V1 of the first node is used as a stable diagnostic reference, and the second node ( Figure 1 The difference between the second voltage V2 (in which the second node is indicated by the second voltage V2) and the first voltage V1 is combined with the control instruction (on or off) of the heating relay K1 to determine whether the heating relay K1 is stuck and cannot be closed or stuck and cannot be opened. However, it has been found that in the charging preheating stage, the first voltage V1 of the first node is sometimes not very stable, resulting in low reliability of the diagnostic result obtained by the diagnostic method.

[0004] It should be noted that the information disclosed in the background technology section of the invention is only intended to deepen the understanding of the general background technology of the invention, and should not be regarded as an admission or suggestion in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to address the problem of low reliability of the fault diagnosis results of the heating relay in the charging preheating stage in the prior art, and to provide a fault diagnosis method, device, electronic device and readable storage medium for a heating relay. The present invention can accurately diagnose whether the heating relay has a stuck and unable to close fault or a stuck and unable to open fault in the charging preheating stage without increasing any hardware cost, thereby significantly improving the diagnostic reliability of the heating relay.

[0006] In order to achieve the above-mentioned object, the present invention is implemented by the following technical scheme: a fault diagnosis method for a heating relay of a battery management system, the battery management system includes a charging preheating equivalent circuit, the charging preheating equivalent circuit includes a first sampling resistor, a second sampling resistor, a third sampling resistor, a fourth sampling resistor, the heating relay and a heating film resistor, the first end of the first sampling resistor, the first end of the second sampling resistor, the first end of the heating relay and the positive electrode of the heating power supply are coupled to a first node, the second end of the first sampling resistor, the second end of the second sampling resistor, the first end of the third sampling resistor and the first end of the fourth sampling resistor are coupled to the high-voltage reference ground of the battery management system, the second end of the third sampling resistor, the second end of the heating relay and the first end of the heating film resistor are coupled to a second node, the second end of the fourth sampling resistor, the second end of the heating film resistor and the negative electrode of the heating power supply are coupled to a third node; the resistance values ​​of the first sampling resistor, the second sampling resistor, the third sampling resistor and the fourth sampling resistor are all greater than the resistance value of the heating film resistor; the relay fault diagnosis method includes:

[0007] Determine whether the preheating start condition is met, and if so, determine whether the insulation monitoring is turned off, and if so, control the heating relay to close and diagnose whether the heating relay is stuck and unable to close according to the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node;

[0008] Determine whether the pre-heating end conditions are met. If so, determine whether the insulation monitoring is turned off. If so, control the heating relay to disconnect and diagnose whether the heating relay is stuck and unable to open based on the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node.

[0009] Optionally, the battery management system further includes an on-board battery and a main positive relay and a main negative relay, wherein the positive electrode of the on-board battery is coupled to the first end of the main positive relay, the second end of the main positive relay is coupled to the first node, and the negative electrode of the on-board battery is coupled to the high-voltage reference ground end and connected in series with the main negative relay;

[0010] The fault diagnosis method includes: if the control unit of the battery management system turns on the charging preheating and at least one of the main positive relay and the main negative relay is disconnected, determining that the preheating start condition is met.

[0011] Optionally, the fault diagnosis method comprises: if the control unit of the battery management system ends the charging preheating and at least one of the main positive relay and the main negative relay is disconnected, determining that the preheating end condition is met.

[0012] Optionally, the charging preheating equivalent circuit further includes a fuse, a first end of the fuse and a first end of the first sampling resistor are coupled to the first node, and a second end of the fuse and a first end of the second sampling resistor, a first end of the heating relay and a positive electrode of the heating power supply are coupled to a fourth node;

[0013] The diagnosing whether the heating relay has a stuck and unable to close fault according to the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node includes:

[0014] diagnose whether the heating relay has a stuck and unable to close fault according to a first voltage at the first node, a second voltage at the second node, a third voltage at the third node, and a fourth voltage at the fourth node;

[0015] The diagnosing whether the heating relay has a stuck and unable to open fault according to the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node includes:

[0016] A diagnosis is made as to whether the heating relay has a stuck and unable to open fault based on a first voltage at the first node, a second voltage at the second node, a third voltage at the third node, and a fourth voltage at the fourth node.

[0017] Optionally, diagnosing whether the heating relay has a stuck and unable to close fault according to the first voltage at the first node, the second voltage at the second node, the third voltage at the third node, and the fourth voltage at the fourth node includes:

[0018] If the first voltage, the second voltage, and the fourth voltage have a first multiple relationship with the heating voltage of the heating power supply, and the third voltage is a first preset value, then the heating relay does not have a stuck and unable to close fault;

[0019] If the first voltage, the fourth voltage and the heating voltage all have the same second multiple relationship, and the second voltage and the third voltage are second preset values, the heating relay has a stuck and unable to close fault; wherein the first multiple is smaller than the second multiple.

[0020] Optionally, diagnosing whether the heating relay has a stuck and unable to open fault according to the first voltage at the first node, the second voltage at the second node, the third voltage at the third node, and the fourth voltage at the fourth node includes:

[0021] If the first voltage, the fourth voltage and the heating voltage all have the same second multiple relationship, and the second voltage and the third voltage are second preset values, then the heating relay does not have a stuck and unable to open fault;

[0022] If the first voltage, the second voltage, and the fourth voltage have the first multiple relationship with the heating voltage of the heating power supply, and the third voltage is a first preset value, the heating relay is stuck and cannot be opened.

[0023] Optionally, the resistance value range of the first sampling resistor, the second sampling resistor, the third sampling resistor and the fourth sampling resistor is 2.5 MΩ to 6 MΩ, and the resistance value range of the heating film resistor is 40Ω to 80Ω.

[0024] In order to achieve the above object, the present invention further provides a heating relay fault diagnosis device for a battery management system, wherein the heating relay fault diagnosis device is used to perform any of the above fault diagnosis methods; the relay fault diagnosis device comprises:

[0025] a stuck and unable to close fault diagnosis unit, configured to determine whether the preheating start condition is met, and if so, determine whether the insulation monitoring is turned off, and if so, control the heating relay to close and diagnose whether the heating relay has a stuck and unable to close fault according to the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node;

[0026] The stuck and unable to open fault diagnosis unit is configured to determine whether the pre-heating end condition is met, and if so, determine whether the insulation monitoring is turned off, and if so, control the heating relay to disconnect and diagnose whether the heating relay has a stuck and unable to open fault based on the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node.

[0027] In order to achieve the above-mentioned purpose, the present invention also provides an electronic device, which includes a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the fault diagnosis method of the heating relay described in any one of the above items is implemented.

[0028] In order to achieve the above-mentioned object, the present invention further provides a readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the fault diagnosis method of the heating relay described in any one of the above items is implemented.

[0029] Compared with the prior art, the heating relay fault diagnosis method, device, electronic device and readable storage medium provided by the present invention have the following advantages:

[0030] The fault diagnosis method for the heating relay provided by the present invention can avoid the influence of insulation monitoring on the first voltage of the first node, thereby ensuring the stability of the first voltage used as a diagnostic benchmark, and can accurately diagnose whether the heating relay has a stuck and unable to close fault or a stuck and unable to open fault in the charging preheating stage, thereby significantly improving the diagnostic reliability of the heating relay, and then improving the safety performance of the electric vehicle; further, the present invention does not require any additional hardware cost, and has simple logic and is easy to implement.

[0031] Since the heating relay fault diagnosis device, electronic device and readable storage medium for a battery management system provided by the present invention belong to the same inventive concept as the heating relay fault diagnosis method provided by the present invention, the heating relay fault diagnosis device, electronic device and readable storage medium provided by the present invention at least have all the advantages of the heating relay fault diagnosis method provided by the present invention. For details on the beneficial effects of the heating relay fault diagnosis device, electronic device and readable storage medium provided by the present invention, please refer to the above description of the beneficial effects of the heating relay fault diagnosis method provided by the present invention, and no further details will be given here. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the topological structure of a high-voltage sampling circuit of a battery management system;

[0033] Figure 2a A schematic diagram of the topological structure of one of the charging preheating equivalent circuits of the battery management system;

[0034] Figure 2bA topological structure diagram of another charging preheating equivalent circuit of a battery management system;

[0035] Figure 3 A schematic diagram of the overall flow of a method for diagnosing a fault of a heating relay provided in the first embodiment of the present invention;

[0036] Figure 4 A detailed flow chart of the heating relay fault diagnosis method provided in the first embodiment of the present invention for diagnosing the heating relay stuck and unable to close fault when charging preheating is turned on;

[0037] Figure 5 A detailed flow chart of the heating relay fault diagnosis method provided in the first embodiment of the present invention for diagnosing a heating relay stuck and unable to open fault at the end of charging preheating;

[0038] Figure 6 A schematic diagram of the block structure of a relay fault diagnosis device provided in Embodiment 2 of the present invention;

[0039] Figure 7 A schematic diagram of the block structure of an electronic device provided in Embodiment 3 of the present invention;

[0040] The reference numerals are as follows:

[0041] Heating relay-K1, heating film resistor-R0, main positive relay-K2, main negative relay-K3, fuse-FU;

[0042] Battery voltage-U1, heating voltage-U2;

[0043] High voltage reference ground terminal - VRef, control unit - MCU;

[0044] A first sampling resistor-R1, a second sampling resistor-R2, a third sampling resistor-R3, and a fourth sampling resistor-R4;

[0045] A first voltage -V1, a second voltage -V2, a third voltage -V3, and a fourth voltage -V4;

[0046] Stuck and unable to close fault diagnosis unit-110, Stuck and unable to open fault diagnosis unit-120;

[0047] Processor 210 , memory 220 , communication interface 230 , communication bus 240 . DETAILED DESCRIPTION

[0048] The following is a further detailed description of a fault diagnosis method, device, electronic device and readable storage medium for a heating relay proposed by the present invention in conjunction with the accompanying drawings. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purposes, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention. Any modification of the structure, change of the proportional relationship or adjustment of the size, in the case of the same or similar effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. The specific design features of the present invention disclosed herein include, for example, specific dimensions, directions, positions and shapes, which will be determined in part by the specific environment to be applied and used. And, in the embodiments described below, sometimes the same figure mark is used to represent the same part or part with the same function between different drawings, and its repeated description is omitted. In this specification, similar reference numerals and letters are used to refer to similar items, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures. In addition, if the method described herein includes a series of steps, the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some of the steps described may be omitted and / or some other steps not described herein may be added to the method.

[0049] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements. The singular forms "a", "an" and "the" include plural objects, the term "or" is generally used in a sense including "and / or", the term "several" is generally used in a sense including "at least one", and the term "at least two" is generally used in a sense including "two or more". In addition, the terms "first", "second" and "third" are used for descriptive purposes only and are not to be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features.

[0050] It should be understood that when an element is referred to as being "connected," "connected to," or "coupled to" another element, it can be directly connected to the other element, or there can be intervening elements. Conversely, when an element is referred to as being "directly connected" or "directly connected to" another element, there are no intervening elements.

[0051] In addition, unless otherwise stated or apparent from the context, as used herein, the term "about" is understood to be within the normal tolerance range in the art, such as within 2 standard deviations of the mean. "About" may be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the value. Unless otherwise clear from the context, all numerical values ​​provided herein are modified by the term "about".

[0052] In order to facilitate the understanding of the present invention, before describing the specific implementation methods of a heating relay fault diagnosis method, device, electronic device and readable storage medium provided by the present invention, the main research process of proposing the present invention is briefly described as follows.

[0053] Please continue to see Figure 1As described in the background art, when diagnosing the fault of the heating relay K1, the related art often uses the first voltage V1 of the first node as a stable diagnostic reference when the main positive relay K2 and the main negative relay K3 are closed. However, in the charging preheating stage, the main positive relay K2 and the main negative relay K3 are in a disconnected state. Affected by factors such as the insulation monitoring function of the battery management system (BMS), the first voltage V1 of the first node is no longer stable. Therefore, the first voltage V1 as the diagnostic reference will become unreliable, and the voltage deviation between the second voltage V2 and the first voltage V1 will be disturbed accordingly. At this time, the stuck and unable to close fault or stuck and unable to open fault of the heating relay K1 is still diagnosed based on the voltage deviation between the second voltage V2 and the first voltage V1, and the reliability of the diagnostic result will inevitably decrease.

[0054] After research, it was found that the insulation monitoring function is a monitoring item required by relevant standards, so the insulation monitoring function must maintain continuity. In other words, the insulation monitoring function cannot be actively turned off during normal preheating. However, after further research, it was found that during the control process, the battery management system will temporarily turn off the insulation monitoring during the process of entering and exiting the preheating state in order to avoid interference from insulation monitoring to other functions. At this time, the influence of insulation monitoring on the first voltage V1 of the first node will be eliminated. If the fault diagnosis of the heating relay K1 is performed at this time, the negative impact on the diagnosis of the heating relay K1 will be indirectly eliminated.

[0055] Based on the above research results, the core idea of ​​the present invention is to provide a fault diagnosis method, device, electronic device and readable storage medium for a heating relay, and to perform fault diagnosis on the heating relay K1 by utilizing the two opportunities when the insulation monitoring is turned off when the charging preheating is turned on and when the charging preheating is turned off. In this way, the negative impact of insulation monitoring can be avoided and the reliability of the diagnosis results can be significantly improved without the need to actively turn off the insulation monitoring.

[0056] It should be noted that the heating relay fault diagnosis method and readable storage medium provided by the present invention can be applied to the heating relay fault diagnosis device and electronic equipment provided by the present invention, and the heating relay fault diagnosis method, device, electronic equipment and readable storage medium provided by the present invention can be applied to electric vehicles. It should be understood that the terms "automobile" or "automobile" or "electric vehicle" or other similar terms used herein include general motor vehicles, such as passenger vehicles including sports utility vehicles (SUVs), buses, trucks, and various commercial vehicles.

[0057] Embodiment 1

[0058] In order to realize the above idea, this embodiment provides a fault diagnosis method for a heating relay of a battery management system, wherein the battery management system includes a charging preheating equivalent circuit. For example, see Figure 2a and Figure 3 ,in, Figure 2a A schematic diagram of the topological structure of one of the charging preheating equivalent circuits of the battery management system; Figure 3 The overall flow chart of the relay fault diagnosis method provided in this embodiment is as follows. Figure 2a It can be seen that the charging preheating equivalent circuit includes a first sampling resistor R1, a second sampling resistor R2, a third sampling resistor R3, a fourth sampling resistor R4, the heating relay K1 and a heating film resistor R0, a first end of the first sampling resistor R1, a first end of the second sampling resistor R2, a first end of the heating relay K1 and a heating power supply (for ease of understanding and explanation, Figure 2a The positive electrode of the heating power source is coupled to the first node ( Figure 2a The first node is indicated by the first voltage V1 in the figure), the second end of the first sampling resistor R1, the second end of the second sampling resistor R2, the first end of the third sampling resistor R3 and the first end of the fourth sampling resistor R4 are coupled to the high voltage reference ground VRef of the battery management system, the second end of the third sampling resistor R3, the second end of the heating relay K1 and the first end of the heating film resistor R0 are coupled to the second node ( Figure 2a The second node is indicated by the second voltage V2 in the figure), the second end of the fourth sampling resistor R4, the second end of the heating film resistor R0 and the negative electrode of the heating power supply are coupled to the third node ( Figure 2a The resistance values ​​of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3 and the fourth sampling resistor R4 are all greater than the resistance value of the heating film resistor R0. Figure 3 It can be seen that the relay fault diagnosis method includes:

[0059] S100: Determine whether the preheating start condition is met, if so, determine whether the insulation monitoring is turned off, if so, control the heating relay K1 to close and diagnose whether the heating relay K1 is stuck and unable to close according to the first voltage V1 at the first node, the second voltage V2 at the second node and the third voltage V3 at the third node;

[0060] S200: Determine whether the pre-heating end condition is met. If so, determine whether the insulation monitoring is turned off. If so, control the heating relay K1 to disconnect and diagnose whether the heating relay K1 is stuck and unable to open based on the first voltage V1 at the first node, the second voltage V2 at the second node and the third voltage V3 at the third node.

[0061] The fault diagnosis method of the heating relay provided by the present invention can avoid the influence of insulation monitoring on the first voltage V1 of the first node, thereby ensuring the stability of the first voltage V1 used as a diagnostic reference, and can accurately diagnose whether the heating relay K1 is stuck and cannot close or is stuck and cannot open and cannot disengage during the charging preheating stage, thereby significantly improving the diagnostic reliability of the heating relay K1, and further improving the safety performance of the electric vehicle; further, the present invention does not require any additional hardware cost, and has simple logic and is easy to implement.

[0062] Preferably, in some exemplary embodiments, the resistance values ​​of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3 and the fourth sampling resistor R4 are in the range of 2.5MΩ to 6MΩ, and the resistance value of the heating film resistor R0 is in the range of 40Ω to 80Ω. Exemplarily, the resistance values ​​of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3 and the fourth sampling resistor R4 are all 3MΩ, and the resistance value of the heating film resistor R0 is 60Ω. It should be noted that, as can be understood by those skilled in the art, the specific values ​​of the resistance values ​​of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3 and the fourth sampling resistor R4 in this document are only exemplary descriptions, not limitations of the present invention. The present invention does not impose too many restrictions on the specific resistance values ​​of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3, the fourth sampling resistor R4 and the heating film resistor R0. For example, the resistance values ​​of the first sampling resistor R1 , the second sampling resistor R2 , the third sampling resistor R3 , and the fourth sampling resistor R4 may be the same or different, and the present invention does not impose any limitation on this.

[0063] It should be noted that, as can be understood by those skilled in the art, the present invention does not impose too many limitations on the heating power supply. For example, in some exemplary embodiments, the heating power supply may be a DC charging pile, that is, the heating film resistor R0 is powered by an external DC charging pile to preheat the vehicle battery. In other exemplary embodiments, the heating power supply may be an AC charging pile. In this case, the battery management system further includes an on-board charger (OBC, On-Board Charger) to convert the AC power provided by the AC charging pile into DC power and then power the heating film resistor R0 to preheat the vehicle battery.

[0064] Please continue to see Figure 1 and Figure 2a By comparison, we can see that Figure 1 In the embodiment, the battery management system also includes a vehicle battery and a main positive relay K2 and a main negative relay K3, the positive pole of the vehicle battery is coupled to the first end of the main positive relay K2, the second end of the main positive relay K2 is coupled to the first node, and the negative pole of the vehicle battery is coupled to the high-voltage reference ground terminal VRef and is connected in series with the main negative relay K3.

[0065] Continue to see Figure 2a and Figure 4 ,in, Figure 4 A detailed flow chart of the heating relay fault diagnosis method provided in the first embodiment of the present invention for diagnosing the heating relay stuck and unable to close fault when the charging preheating is turned on. Figure 4 It can be seen that in some preferred embodiments, the fault diagnosis method includes: if the control unit of the battery management system turns on the charging preheating and at least one of the main positive relay K2 and the main negative relay K3 is disconnected, it is determined that the preheating start condition is met.

[0066] Therefore, the fault diagnosis method of the heating relay provided by the present invention satisfies the preheating start-up condition including that the control unit of the battery management system starts charging preheating, thereby ensuring that the fault diagnosis of the heating relay K1 is performed before charging preheating, thereby laying a good foundation for ensuring that the charging preheating circuit is in a correct working state; further, satisfying the preheating start-up condition also includes at least one of the main positive relay K2 and the main negative relay K3 being disconnected, thereby preventing the battery voltage U1 from affecting the first voltage V1, the second voltage V2, the third voltage V3 and the fourth voltage V4 (for more details, please refer to the following about Figure 2b ), thereby improving the reliability of the fault diagnosis of the heating relay K1 being stuck and unable to close.

[0067] See also Figure 5 , Figure 5 A detailed flow chart of the heating relay fault diagnosis method provided in the first embodiment of the present invention for diagnosing the heating relay stuck and unable to open fault at the end of charging preheating. Figure 5 It can be seen that in some preferred embodiments, the fault diagnosis method includes: if the control unit of the battery management system ends the charging preheating and at least one of the main positive relay K2 and the main negative relay K3 is disconnected, it is determined that the preheating end condition is met.

[0068] Therefore, the fault diagnosis method of the heating relay provided by the present invention, when the preheating end condition is met, includes the control unit of the battery management system ending the charging preheating, thereby ensuring that the fault diagnosis of the heating relay K1 is performed after the charging preheating is completed, thereby laying a good foundation for ensuring that the temperature of the battery rises to a reasonable range to avoid overheating; further, when the preheating end condition is met, it also includes at least one of the main positive relay K2 and the main negative relay K3 being disconnected, thereby preventing the battery voltage U1 from affecting the first voltage V1, the second voltage V2, the third voltage V3 and the fourth voltage V4 (for more details, please refer to the following about Figure 2b ), thereby improving the reliability of fault diagnosis of the heating relay K1 being stuck and unable to open.

[0069] By comparison Figure 1 and Figure 2a It can be found that Figure 2a The charging preheating equivalent circuit in the embodiment is that when at least one of the main positive relay K2 and the main negative relay K3 is disconnected Figure 1 In other words, when the main positive relay K2 and / or the main negative relay K3 are disconnected and charging preheating is performed, the load resistors Ra, Rb, Rc, Rd and the sampling resistor R5 in the battery management system are in a non-working state.

[0070] For example, in some exemplary embodiments, when the control unit MCU of the battery management system determines that the charging preheating function needs to be turned on under low temperature, the main positive relay K2 and / or the main negative relay K3 are disconnected, and the state machine controls the process of jumping into the preheating state. Ideally, the influence of the battery voltage U1 on the first voltage V1, the second voltage V2, the third voltage V3 and the fourth voltage V4 can be avoided, and the diagnosis of the relay stuck and unable to close fault is more reliable.

[0071] Please continue to see Figure 1 and Figure 2b ,in, Figure 2b This is a topological diagram of another charging preheating equivalent circuit of the battery management system. Figure 1 and Figure 2b It can be seen that in some exemplary embodiments, the charging preheating equivalent circuit further includes a fuse FU, a first end of the fuse FU and a first end of the first sampling resistor R1 are coupled to the first node, and a second end of the fuse FU and a first end of the second sampling resistor R2, a first end of the heating relay K1 and a positive electrode of the heating power supply are coupled to a fourth node ( Figure 2b The fourth node is indicated by a fourth voltage V4).

[0072] Correspondingly, the step S100 of diagnosing whether the heating relay K1 has a stuck and unable to close fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, and the third voltage V3 at the third node includes:

[0073] It is diagnosed whether the heating relay K1 has a stuck and unable to close fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, the third voltage V3 at the third node and the fourth voltage V4 at the fourth node.

[0074] The step S200 of diagnosing whether the heating relay K1 has a stuck and unable to open fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, and the third voltage V3 at the third node includes:

[0075] It is diagnosed whether the heating relay K1 has a stuck and unable to open fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, the third voltage V3 at the third node and the fourth voltage V4 at the fourth node.

[0076] Therefore, the fault diagnosis method of the heating relay provided by the present invention can further improve the reliability of the stuck and unable to close fault diagnosis by diagnosing whether the heating relay K1 has a stuck and unable to close fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, the third voltage V3 at the third node, and the fourth voltage V4 at the fourth node; and can further improve the reliability of the stuck and unable to open fault diagnosis by diagnosing whether the heating relay K1 has a stuck and unable to open fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, the third voltage V3 at the third node, and the fourth voltage V4 at the fourth node.

[0077] Please continue to see Figure 4In some exemplary embodiments, the diagnosing whether the heating relay K1 has a stuck and unable to close fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, the third voltage V3 at the third node, and the fourth voltage V4 at the fourth node includes:

[0078] If the first voltage V1, the second voltage V2 and the fourth voltage V4 have a first multiple relationship with the heating voltage U2 of the heating power source, and the third voltage V3 is a first preset value, then the heating relay K1 does not have a stuck and unable to close fault;

[0079] If the first voltage V1, the fourth voltage V4 and the heating voltage U2 all have the same second multiple relationship, and the second voltage V2 and the third voltage V3 are second preset values, the heating relay K1 has a stuck and unable to close fault; wherein the first multiple is smaller than the second multiple.

[0080] Therefore, the fault diagnosis method of the heating relay provided by the present invention, when the insulation monitoring is turned off and the heating relay K1 is closed, diagnoses whether the heating relay K1 is stuck and cannot close by making full use of the topological structure of the charging preheating equivalent circuit. This not only improves the reliability of the diagnosis result, but also has simple logic and is easy to implement.

[0081] It should be noted that, as those skilled in the art can understand, the present invention does not impose too many restrictions on the specific values ​​of the first multiple and the second multiple, and the specific values ​​of the first multiple and the second multiple are determined by the resistance values ​​of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3 and the fourth sampling resistor R4.

[0082] For example, in one specific example, if the resistance values ​​of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3 and the fourth sampling resistor R4 are all 3MΩ, the resistance value of the heating film resistor R0 is 60Ω. When a heating power source is used for charging preheating, the battery management system controls the heating relay K1 to close.

[0083] If the heating relay K1 is truly closed, that is, the heating relay K1 does not have a stuck and unable to close fault: then the first sampling resistor R1 of the first node, the second sampling resistor R2 of the fourth node, the third sampling resistor R3 of the second node, and the fourth sampling resistor R4 of the third node (compared with the resistance of the sampling resistor 3MΩ, the resistance of the heating film resistor R0 is 60Ω, which is very small and can be ignored) are connected in parallel, and the first voltage V1 at the first node, the fourth voltage V4 at the fourth node, and the second voltage V2 at the second node are all equal to: U2×0.25 (that is, the first multiple is 0.25); theoretically, the third voltage V3 at the third node is equal to: -U2×0.75, combined with the fact that the high-voltage sampling chip does not support the sampling of negative voltages under normal circumstances, the third voltage V3 is actually displayed to be equal to 0 (that is, the first preset value). Therefore, when the first voltage V1, the second voltage V2, and the fourth voltage V4 have a first multiple relationship with the heating voltage U2 of the heating power supply, and the third voltage V3 is the first preset value, it can be determined that the heating relay K1 does not have a stuck and unable to close fault.

[0084] If the heating relay K1 has a stuck and unable to close fault: then the first sampling resistor R1 of the first node and the fourth sampling resistor R4 of the fourth node are connected in parallel, and the first voltage V1 at the first node and the fourth voltage V4 at the fourth node are both equal to: U2×0.5 (i.e., the second multiple); theoretically, the second voltage V2 at the second node and the third voltage V3 at the third node are both equal to: -U2×0.5, combined with the fact that the high-voltage sampling chip does not support the sampling of negative voltages under normal circumstances, the second voltage V2 and the third voltage V3 are actually displayed to be equal to 0 (i.e., the second preset value). Therefore, when the first voltage V1, the fourth voltage V4 and the heating voltage U2 all have the same second multiple relationship, and the second voltage V2 and the third voltage V3 are the second preset value, it can be determined that the heating relay K1 has a stuck and unable to close fault.

[0085] Please continue to see Figure 5 In some exemplary embodiments, the diagnosing whether the heating relay K1 has a stuck and unable to open fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, the third voltage V3 at the third node, and the fourth voltage V4 at the fourth node includes:

[0086] If the first voltage V1, the fourth voltage V4 and the heating voltage U2 all have the same second multiple relationship, and the second voltage V2 and the third voltage V3 are second preset values, the heating relay K1 does not have a stuck and unable to open fault;

[0087] If the first voltage V1, the second voltage V2 and the fourth voltage V4 have the first multiple relationship with the heating voltage U2 of the heating power supply, and the third voltage V3 is a first preset value, the heating relay K1 is stuck and cannot be opened.

[0088] Therefore, the fault diagnosis method of the heating relay provided by the present invention, when the insulation monitoring is turned off and the heating relay K1 is disconnected, diagnoses whether the heating relay K1 is stuck and cannot be opened by making full use of the topological structure of the charging preheating equivalent circuit. This not only improves the reliability of the diagnosis result, but also has simple logic and is easy to implement.

[0089] For example, in one specific example, if the resistance values ​​of the first sampling resistor R1, the second sampling resistor R2, the third sampling resistor R3 and the fourth sampling resistor R4 are all 3MΩ, the resistance value of the heating film resistor R0 is 60Ω. When the preheating of charging using the heating power supply is completed, the battery management system will control the heating relay K1 to disconnect.

[0090] If the heating relay K1 is truly disconnected, that is, the heating relay K1 does not have a stuck and unable to open fault: then the first sampling resistor R1 of the first node and the fourth sampling resistor R4 of the fourth node are connected in parallel, and the first voltage V1 at the first node and the fourth voltage V4 at the fourth node are both equal to: U2×0.5 (i.e., the second multiple); theoretically, the second voltage V2 at the second node and the third voltage V3 at the third node are both equal to: -U2×0.5, combined with the fact that the high-voltage sampling chip does not support the sampling of negative voltages under normal circumstances, the second voltage V2 and the third voltage V3 are actually displayed to be equal to 0 (i.e., the second preset value). Therefore, when the first voltage V1, the fourth voltage V4 and the heating voltage U2 all have the same second multiple relationship, and the second voltage V2 and the third voltage V3 are the second preset values, it can be determined that the heating relay K1 does not have a stuck and unable to open fault.

[0091] If the heating relay K1 is stuck and cannot be opened: then the first sampling resistor R1 of the first node, the second sampling resistor R2 of the fourth node, the third sampling resistor R3 of the second node and the fourth sampling resistor R4 of the third node (compared with the resistance of the sampling resistor 3MΩ, the resistance of the heating film resistor R0 is 60Ω, which is very small and can be ignored) are connected in parallel, and the first voltage V1 at the first node, the fourth voltage V4 at the fourth node and the second voltage V2 at the second node are all equal to: U2×0.25 (that is, the first multiple is 0.25); theoretically, the third voltage V3 at the third node is equal to: -U2×0.75, combined with the fact that the high-voltage sampling chip does not support the sampling of negative voltages under normal circumstances, the third voltage V3 is actually displayed to be equal to 0 (that is, the first preset value). Therefore, when the first voltage V1, the second voltage V2 and the fourth voltage V4 have the first multiple relationship with the heating voltage U2 of the heating power supply, and the third voltage V3 is the first preset value, it can be determined that the heating relay K1 is stuck and cannot be opened.

[0092] In summary, according to the description in this article, the fault diagnosis method of the heating relay provided by the present invention diagnoses whether the heating relay K1 is stuck and cannot be closed when the charging preheating is turned on (the insulation monitoring function is turned off at this time) and diagnoses whether the heating relay K1 is stuck and cannot be opened when the charging preheating is ended (the insulation monitoring function is turned off at this time). This can not only ensure that the heating relay K1 is in the correct working state; but also avoid the negative impact of insulation monitoring, and significantly improve the reliability of the diagnosis results.

[0093] Embodiment 2

[0094] This embodiment provides a heating relay fault diagnosis device for a battery management system, and the heating relay fault diagnosis device is used to perform the fault diagnosis method described in any implementation method of the first embodiment. Figure 2a as well as Figure 6 , Figure 6 The block diagram of the relay fault diagnosis device provided in this embodiment is as follows. Figure 6It can be seen that the relay fault diagnosis device includes a stuck and unable to close fault diagnosis unit 110 and a stuck and unable to open fault diagnosis unit 120. Exemplarily, the stuck and unable to close fault diagnosis unit 110 is configured to determine whether the preheating start condition is met, if so, determine whether the insulation monitoring is turned off, if so, control the heating relay K1 to close and diagnose whether the heating relay K1 has a stuck and unable to close fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, and the third voltage V3 at the third node. The stuck and unable to open fault diagnosis unit 120 is configured to determine whether the preheating end condition is met, if so, determine whether the insulation monitoring is turned off, if so, control the heating relay K1 to open and diagnose whether the heating relay K1 has a stuck and unable to open fault according to the first voltage V1 at the first node, the second voltage V2 at the second node, and the third voltage V3 at the third node.

[0095] Configured in this way, the relay fault diagnosis device provided by the present invention can avoid the influence of insulation monitoring on the first voltage of the first node, thereby ensuring the stability of the first voltage used as a diagnostic benchmark, and can accurately diagnose whether the heating relay has a stuck and unable to close fault or a stuck and unable to open fault during the charging preheating stage, thereby significantly improving the diagnostic reliability of the heating relay, and further improving the safety performance of the electric vehicle; further, the present invention does not require any additional hardware cost, and has simple logic and is easy to implement.

[0096] Since the heating relay fault diagnosis device for a battery management system provided by the present invention has the same basic principle as the heating relay fault diagnosis method provided by the present invention, in order to avoid redundancy, the heating relay fault diagnosis device provided by the present invention will not be described in detail herein. For more detailed contents about the heating relay fault diagnosis device provided by the present invention, please refer to the adaptive understanding of the relevant contents about the heating relay fault diagnosis method provided by the present invention in Example 1.

[0097] Embodiment 3

[0098] This embodiment provides an electronic device. For example, see Figure 7 , Figure 7 Schematic diagram of the block structure of the electronic device provided in this embodiment. Figure 7As shown, the electronic device provided in this embodiment includes a processor 210 and a memory 220, and a computer program is stored in the memory 220. When the computer program is executed by the processor 210, the fault diagnosis method for the heating relay provided in any of the above embodiments is implemented. Since the electronic device provided in this embodiment and the fault diagnosis method for the heating relay provided in the present invention belong to the same inventive concept, the electronic device provided in this embodiment has at least all the advantages of the fault diagnosis method for the heating relay provided in the present invention. For details, please refer to the above description of the beneficial effects of the fault diagnosis method for the heating relay, which will not be repeated here.

[0099] For example, Figure 7 As shown, the electronic device may further include a communication interface 230 and a communication bus 240, wherein the processor 210, the communication interface 230, and the memory 220 communicate with each other via the communication bus 240. The communication bus 240 includes but is not limited to a CAN bus, etc., and the communication bus 240 may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus. The communication interface 230 is used for communication between the above-mentioned electronic device and other devices.

[0100] The processor 210 referred to in the present invention may be a microcontroller unit (MCU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor 210 is the control center of the electronic device, and uses various interfaces and lines to connect various parts of the entire electronic device.

[0101] The memory 220 may be used to store the computer program, and the processor 210 implements various functions of the electronic device by running or executing the computer program stored in the memory 220 and calling the data stored in the memory 220 .

[0102] The memory 220 may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0103] Embodiment 4

[0104] The present embodiment provides a readable storage medium, wherein a computer program is stored in the readable storage medium, and when the computer program is executed by a processor, the above-mentioned heating relay fault diagnosis method can be implemented. Since the readable storage medium provided by the present invention and the heating relay fault diagnosis method provided by the present invention belong to the same inventive concept, the readable storage medium provided by the present invention at least has all the advantages of the heating relay fault diagnosis method provided by the present invention. For details of the beneficial effects of the readable storage medium provided by the present invention, please refer to the above description of the beneficial effects of the heating relay fault diagnosis method provided by the present invention, which will not be repeated here.

[0105] The readable storage medium of the embodiment of the present invention can adopt any combination of one or more computer-readable media. The readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared or semiconductor, or any combination of the above. More specific examples (non-exhaustive examples) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer hard disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this article, a computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, a device or a device or used in combination with it.

[0106] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, which carry computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0107] Computer program code for performing the operation of the present invention may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0108] Compared with the prior art, the heating relay fault diagnosis method, device, electronic device and readable storage medium provided by the present invention have the following advantages:

[0109] The fault diagnosis method for the heating relay provided by the present invention can avoid the influence of insulation monitoring on the first voltage of the first node, thereby ensuring the stability of the first voltage used as a diagnostic benchmark, and can accurately diagnose whether the heating relay has a stuck and unable to close fault or a stuck and unable to open fault in the charging preheating stage, thereby significantly improving the diagnostic reliability of the heating relay, and then improving the safety performance of the electric vehicle; further, the present invention does not require any additional hardware cost, and has simple logic and is easy to implement.

[0110] Since the heating relay fault diagnosis device, electronic device and readable storage medium for a battery management system provided by the present invention belong to the same inventive concept as the heating relay fault diagnosis method provided by the present invention, the heating relay fault diagnosis device, electronic device and readable storage medium provided by the present invention at least have all the advantages of the heating relay fault diagnosis method provided by the present invention. For details on the beneficial effects of the heating relay fault diagnosis device, electronic device and readable storage medium provided by the present invention, please refer to the above description of the beneficial effects of the heating relay fault diagnosis method provided by the present invention, and no further details will be given here.

[0111] It should be noted that the devices and methods disclosed in the embodiments of this article can also be implemented in other ways. The device implementation described above is only schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of this article. In this regard, each box in the flowchart or block diagram can represent a part of a module, program or code, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical function, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented by a dedicated hardware-based system for performing a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0112] In addition, the functional modules in the various embodiments of this document may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0113] The above description is only a description of the preferred implementation of the fault diagnosis method, device, electronic device and readable storage medium of the heating relay provided by the present invention, and is not any limitation on the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure content belong to the protection scope of the present invention. Obviously, technicians in this field can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations fall within the scope of the present invention and its equivalent technology, the present invention is also intended to include these modifications and variations.

Claims

1. A fault diagnosis method for a heating relay of a battery management system, characterized in that: The battery management system includes a charging preheating equivalent circuit, which includes a first sampling resistor, a second sampling resistor, a third sampling resistor, a fourth sampling resistor, the heating relay and a heating film resistor, wherein the first end of the first sampling resistor, the first end of the second sampling resistor, the first end of the heating relay and the positive electrode of the heating power supply are coupled to a first node, the second end of the first sampling resistor, the second end of the second sampling resistor, the first end of the third sampling resistor and the first end of the fourth sampling resistor are coupled to a high-voltage reference ground of the battery management system, the second end of the third sampling resistor, the second end of the heating relay and the first end of the heating film resistor are coupled to a second node, and the second end of the fourth sampling resistor, the second end of the heating film resistor and the negative electrode of the heating power supply are coupled to a third node; the resistance values ​​of the first sampling resistor, the second sampling resistor, the third sampling resistor and the fourth sampling resistor are all greater than the resistance value of the heating film resistor; The relay fault diagnosis method comprises: Determine whether the preheating start condition is met, and if so, determine whether the insulation monitoring is turned off, and if so, control the heating relay to close and diagnose whether the heating relay is stuck and unable to close according to the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node; Determine whether the pre-heating end conditions are met. If so, determine whether the insulation monitoring is turned off. If so, control the heating relay to disconnect and diagnose whether the heating relay is stuck and unable to open based on the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node.

2. The fault diagnosis method according to claim 1, characterized in that: The battery management system further includes an on-board battery, a main positive relay and a main negative relay, wherein the positive electrode of the on-board battery is coupled to the first end of the main positive relay, the second end of the main positive relay is coupled to the first node, and the negative electrode of the on-board battery is coupled to the high-voltage reference ground end and connected in series with the main negative relay; The fault diagnosis method includes: if the control unit of the battery management system turns on the charging preheating and at least one of the main positive relay and the main negative relay is disconnected, determining that the preheating start condition is met.

3. The fault diagnosis method according to claim 2, characterized in that: The fault diagnosis method includes: if the control unit of the battery management system ends the charging preheating and at least one of the main positive relay and the main negative relay is disconnected, determining that the preheating end condition is met.

4. The fault diagnosis method according to claim 1, characterized in that: The charging preheating equivalent circuit further includes a fuse, wherein a first end of the fuse and a first end of the first sampling resistor are coupled to the first node, and a second end of the fuse and a first end of the second sampling resistor, a first end of the heating relay, and a positive electrode of the heating power supply are coupled to a fourth node; The diagnosing whether the heating relay has a stuck and unable to close fault according to the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node includes: diagnose whether the heating relay has a stuck and unable to close fault according to a first voltage at the first node, a second voltage at the second node, a third voltage at the third node, and a fourth voltage at the fourth node; The diagnosing whether the heating relay has a stuck and unable to open fault according to the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node comprises: A diagnosis is made as to whether the heating relay has a stuck and unable to open fault based on a first voltage at the first node, a second voltage at the second node, a third voltage at the third node, and a fourth voltage at the fourth node.

5. The fault diagnosis method according to claim 4, characterized in that: The diagnosing whether the heating relay has a stuck and unable to close fault according to the first voltage at the first node, the second voltage at the second node, the third voltage at the third node, and the fourth voltage at the fourth node includes: If the first voltage, the second voltage, and the fourth voltage have a first multiple relationship with the heating voltage of the heating power supply, and the third voltage is a first preset value, then the heating relay does not have a stuck and unable to close fault; If the first voltage, the fourth voltage and the heating voltage all have the same second multiple relationship, and the second voltage and the third voltage are second preset values, the heating relay has a stuck and unable to close fault; wherein the first multiple is smaller than the second multiple.

6. The fault diagnosis method according to claim 5, characterized in that: The diagnosing whether the heating relay has a stuck and unable to open fault according to the first voltage at the first node, the second voltage at the second node, the third voltage at the third node, and the fourth voltage at the fourth node includes: If the first voltage, the fourth voltage and the heating voltage all have the same second multiple relationship, and the second voltage and the third voltage are second preset values, then the heating relay does not have a stuck and unable to open fault; If the first voltage, the second voltage, and the fourth voltage have the first multiple relationship with the heating voltage of the heating power supply, and the third voltage is a first preset value, the heating relay is stuck and cannot be opened.

7. The fault diagnosis method according to any one of claims 1 to 6, characterized in that: The resistance value range of the first sampling resistor, the second sampling resistor, the third sampling resistor and the fourth sampling resistor is 2.5MΩ to 6MΩ, and the resistance value range of the heating film resistor is 40Ω to 80Ω.

8. A heating relay fault diagnosis device for a battery management system, characterized in that: The heating relay fault diagnosis device is used to perform the fault diagnosis method according to any one of claims 1 to 7; the relay fault diagnosis device comprises: a stuck and unable to close fault diagnosis unit, configured to determine whether the preheating start condition is met, and if so, determine whether the insulation monitoring is turned off, and if so, control the heating relay to close and diagnose whether the heating relay has a stuck and unable to close fault according to the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node; The stuck and unable to open fault diagnosis unit is configured to determine whether the pre-heating end condition is met, and if so, determine whether the insulation monitoring is turned off, and if so, control the heating relay to disconnect and diagnose whether the heating relay has a stuck and unable to open fault based on the first voltage at the first node, the second voltage at the second node, and the third voltage at the third node.

9. An electronic device, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the fault diagnosis method for the heating relay according to any one of claims 1 to 7 is implemented.

10. A readable storage medium, characterized in that: The readable storage medium stores a computer program, and when the computer program is executed by a processor, the fault diagnosis method for the heating relay according to any one of claims 1 to 7 is implemented.

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