Relay failure detection apparatus and method for a battery system

Abstract

The application provides a relay fault detection device and method of a battery system. The device comprises a power supply unit, a voltage detection unit, a current detection unit and a fault latch unit; the power supply unit supplies power to the voltage detection unit, the current detection unit and the fault latch unit; the voltage detection unit detects the voltage of a load bus of the battery system and generates a voltage state signal, and sends the voltage state signal to the fault latch unit; if the voltage does not exceed a voltage threshold, an enable valid signal is sent to the current detection unit; the current detection unit receives the enable valid signal, detects the current of a load loop and generates a current state signal, and sends the current state signal to the fault latch unit; the fault latch unit receives the voltage state signal and the current state signal, and determines the detection result of the relay contact fault according to the voltage state signal and the current state signal. The device judges whether the load relay contact is stuck through the voltage state signal and the current state signal, and the accuracy is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a relay fault detection device and method of battery system. BACKGROUND

[0002] The high-voltage output process of the battery system is that the positive and negative relays of the battery system are attracted, and the output is output to each load through the bus, so that the load works normally. In order to improve the safety of the high-voltage output of the battery system, a pre-charging process is required when the high-voltage output is performed. The pre-charging circuit can be located in each load circuit, and when the load relay contact is stuck, the pre-charging circuit will be disabled, so it is necessary to detect whether the load relay is stuck.

[0003] The existing relay contact sticking detection usually adopts the contact voltage method, that is, the voltage before and after the relay contact is detected to determine whether the relay contact is stuck.

[0004] However, before the positive and negative relays of the battery system are attracted, the load power supply bus has no voltage, so there is no voltage across the load relay contact, and therefore the contact voltage method cannot be used to determine whether the load relay is stuck, and the accuracy is low. SUMMARY

[0005] The present application provides a relay fault detection device and method of battery system to solve the problem of low accuracy when using the existing contact voltage method to determine whether the load relay contact is stuck.

[0006] In a first aspect, the present application provides a relay fault detection device of battery system, comprising: a power supply unit, a voltage detection unit, a current detection unit and a fault latching unit;

[0007] The power supply unit is used to supply power to the voltage detection unit, the current detection unit and the fault latching unit;

[0008] The voltage detection unit is used to detect the voltage of the load bus of the battery system to be tested and generate a voltage state signal, and send the voltage state signal to the fault latching unit; if the voltage does not exceed the voltage threshold, send an enable valid signal to the current detection unit;

[0009] The current detection unit is used to receive the enable valid signal, detect the current of the load circuit and generate a current state signal, and send the current state signal to the fault latching unit;

[0010] The fault latching unit is used to receive the voltage state signal and the current state signal, and determine the detection result of the relay contact fault according to the voltage state signal and the current state signal.

[0011] In a possible design, the voltage state signal includes a voltage fault signal and a voltage non-fault signal; the voltage detection unit is specifically configured to:

[0012] The voltage detection unit detects the voltage of the load bus, and determines whether the voltage is higher than a voltage threshold value;

[0013] If the voltage is higher than the voltage threshold value, the voltage fault signal is generated;

[0014] If the voltage is lower than the voltage threshold value, the voltage non-fault signal is generated.

[0015] In a possible design, the current state signal includes a current fault signal and a current non-fault signal; the current detection unit includes a current detection circuit and an excitation source circuit; the current detection unit is specifically configured to:

[0016] The excitation source circuit is configured to receive an enable valid signal, and output an excitation signal to the load bus;

[0017] The current detection circuit is configured to receive the enable valid signal, detect the current of the load loop, and determine whether the current is higher than a current threshold value;

[0018] If the current is higher than the current threshold value, the current fault signal is generated;

[0019] If the current is lower than the current threshold value, the current non-fault signal is generated.

[0020] In a possible design, the fault latching unit is specifically configured to:

[0021] If the voltage state signal is the voltage non-fault signal and the current state signal is the current non-fault signal, it is determined that the detection result of the relay contact fault is a normal state;

[0022] If the voltage state signal is the voltage fault signal or the current state signal is the current fault signal, it is determined that the detection result of the relay contact fault is a fault state.

[0023] In a possible design, the fault latching unit is further configured to:

[0024] Send the detection result of the relay contact fault to the battery management system, so that the battery management system controls the output end of the battery, and the voltage output by the output end is higher than a set threshold value.

[0025] In a possible design, the power supply unit is specifically configured to:

[0026] The power supply unit receives the voltage output by the battery management system, and outputs a board card working voltage, which is used to supply power to the voltage detection unit, the current detection unit and the fault latching unit.

[0027] In a second aspect, the application provides a relay fault detection method for a battery system, comprising:

[0028] receiving a voltage sent by a battery management system, the voltage being used to provide power for a relay fault detection device of the battery system;

[0029] detecting a voltage of a load bus and generating a voltage status signal;

[0030] if the voltage does not exceed a voltage threshold, detecting a current of a load loop and generating a current status signal;

[0031] generating a detection result of a relay contact fault according to the voltage status signal and the current status signal.

[0032] In a possible design of the application, the voltage status signal comprises a voltage fault signal and a voltage non-fault signal; and the detecting of the voltage of the load bus and the generating of the voltage status signal comprises:

[0033] detecting the voltage of the load bus and determining whether the voltage is higher than the voltage threshold;

[0034] if the voltage is higher than the voltage threshold, generating the voltage fault signal;

[0035] if the voltage is lower than the voltage threshold, generating the voltage non-fault signal.

[0036] In a possible design of the application, the current status signal comprises a current fault signal and a current non-fault signal; and the detecting of the current of the load loop and the generating of the current status signal comprises:

[0037] detecting the current of the load loop and determining whether the current is higher than a current threshold;

[0038] if the current is higher than the current threshold, generating the current fault signal;

[0039] if the current is lower than the current threshold, generating the current non-fault signal.

[0040] In a possible design of the application, the generating of the detection result of the relay contact fault according to the voltage status signal and the current status signal comprises:

[0041] if the voltage status signal is the voltage non-fault signal and the current status signal is the current non-fault signal, determining that the detection result of the relay contact fault is a normal state;

[0042] if the voltage status signal is the voltage fault signal or the current status signal is the current fault signal, determining that the detection result of the relay contact fault is a fault state.

[0043] The application provides a relay fault detection device and method of a battery system. The device comprises a power supply unit, a voltage detection unit, a current detection unit and a fault latch unit. The power supply unit supplies power to the voltage detection unit, the current detection unit and the fault latch unit. The voltage detection unit detects the voltage of a load bus of the battery and generates a voltage state signal, and sends the voltage state signal to the fault latch unit. If the voltage does not exceed a voltage threshold, the voltage detection unit also sends an enable valid signal to the current detection unit. The current detection unit receives the enable valid signal, detects the current of a load loop and generates a current state signal, and sends the current state signal to the fault latch unit. The fault latch unit receives the voltage state signal and the current state signal, and determines the detection result of the relay contact fault according to the voltage state signal and the current state signal. The method provided by the application determines the detection result of the relay contact fault according to the voltage of the load bus and the current of the load loop, and improves the accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0044] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the principles of the application.

[0045] Figure 1 A battery system schematic diagram provided for an embodiment of the application;

[0046] Figure 2 A battery system relay fault detection device provided for an embodiment of the application detects a load relay contact fault schematic diagram;

[0047] Figure 3 A battery system relay fault detection device provided for an embodiment of the application schematic Figure 1 ;

[0048] Figure 4 A battery system relay fault detection device provided for an embodiment of the application schematic Figure 2 ;

[0049] Figure 5 A battery system relay fault detection method flow provided for an embodiment of the application Figure 1 ;

[0050] Figure 6 A battery system relay fault detection method flow provided for an embodiment of the application Figure 2 .

[0051] Through the above drawings, the specific embodiments of the application have been shown, and will be described in more detail hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the application by any means, but to illustrate the concept of the application to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0052] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0053] A battery system consists of many individual battery cells connected in series and parallel to achieve the required capacity and voltage output platform. The high-voltage output process involves the activation of the positive and negative relays of the battery system, which then outputs the voltage to various loads via the bus, enabling the loads to operate normally. To improve the safety of the high-voltage output, a pre-charging process is required before the battery system can output high voltage. This pre-charging process protects the positive and negative relays of the battery system from activating properly and also protects the loads from being burned out by a direct inrush of high-voltage current.

[0054] To save costs, the precharge circuit is usually distributed across various load circuits. When the load relay contacts in a load circuit stick together, the precharge circuit will fail. If the battery system's positive and negative relays are closed in this situation, the relays will close under load, leading to erosion and sticking of the battery system's positive and negative relay contacts. Therefore, it is necessary to check for sticking of the load relay contacts before the battery pack outputs high voltage.

[0055] Existing methods for detecting relay contact sticking involve measuring the voltage across the relay contacts. However, since there is no voltage on the load bus before the positive and negative relays in the battery system engage, there is also no voltage across the load relay contacts. Therefore, this method is ineffective in determining whether the relay contacts are stuck, resulting in low accuracy.

[0056] This application utilizes the characteristic of capacitive loads in the load circuit to determine whether the load relay contacts are stuck by using a relay fault detection device in the battery system. This device detects the load bus voltage and load circuit current before the positive and negative relays of the battery system close. When stuck load relay contacts are detected, the high-voltage output of the battery system is prohibited to prevent the positive and / or negative relays from closing under load due to stuck load relay contacts, which could damage the positive and / or negative relays. This method offers high accuracy.

[0057] Figure 1 This is a schematic diagram of a battery system provided as an embodiment of this application. Figure 1As shown in the figure, the battery system includes two parts of a battery pack and a load loop, wherein the battery pack includes a battery and a battery management system. K1 is a positive relay of the battery system, K2 is a negative relay of the battery system, K3 is a load relay, and a load pre-charging relay K4 and a pre-charging resistor R1 form a pre-charging loop. CL is a load loop capacitor, and ZL is an equivalent impedance of the load loop. LINK+ and LINK- are positive and negative bus bars of the load, respectively. The application uses a relay fault detection device of the battery system to detect whether the contact of the load relay K3 is stuck. Figure 2 As shown in the figure, the battery system includes two parts of a battery pack and a load loop, wherein the battery pack includes a battery and a battery management system. K1 is a positive relay of the battery system, K2 is a negative relay of the battery system, K3 is a load relay, and a load pre-charging relay K4 and a pre-charging resistor R1 form a pre-charging loop. CL is a load loop capacitor, and ZL is an equivalent impedance of the load loop. LINK+ and LINK- are positive and negative bus bars of the load, respectively. The application uses a relay fault detection device of the battery system to detect whether the contact of the load relay K3 is stuck. Figure 2 As shown in the figure, the battery system includes two parts of a battery pack and a load loop, wherein the battery pack includes a battery and a battery management system. K1 is a positive relay of the battery system, K2 is a negative relay of the battery system, K3 is a load relay, and a load pre-charging relay K4 and a pre-charging resistor R1 form a pre-charging loop. CL is a load loop capacitor, and ZL is an equivalent impedance of the load loop. LINK+ and LINK- are positive and negative bus bars of the load, respectively. The application uses a relay fault detection device of the battery system to detect whether the contact of the load relay K3 is stuck.

[0058] The following specific embodiments will be described in detail below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described in some embodiments. The embodiments of the application will be described below with reference to the accompanying drawings.

[0059] Figure 3 A schematic diagram of a relay fault detection device of a battery system according to an embodiment of the application is shown in the figure. Figure 1 As shown in the figure, the battery system includes two parts of a battery pack and a load loop, wherein the battery pack includes a battery and a battery management system. K1 is a positive relay of the battery system, K2 is a negative relay of the battery system, K3 is a load relay, and a load pre-charging relay K4 and a pre-charging resistor R1 form a pre-charging loop. CL is a load loop capacitor, and ZL is an equivalent impedance of the load loop. LINK+ and LINK- are positive and negative bus bars of the load, respectively. The application uses a relay fault detection device of the battery system to detect whether the contact of the load relay K3 is stuck. Figure 3 As shown in the figure, the relay fault detection device can include a power supply unit 301, a voltage detection unit 302, a current detection unit 303, and a fault latching unit 304.

[0060] The power supply unit 301 is used to supply power to the voltage detection unit 302, the current detection unit 303, and the fault latching unit 304.

[0061] In one implementation scenario, the power supply unit 301 receives the voltage output by the battery management system and outputs a board working voltage, which is used to supply power to the voltage detection unit 302, the current detection unit 303, and the fault latching unit 304. Since whether the power supply unit 301 outputs the board working voltage depends on the voltage output by the battery management system, the power supply unit 301 is controlled by the battery management system.

[0062] The voltage output by the battery management system is usually a low voltage, for example, 12V or 24V. It should be noted that the power supply unit 301 will output the board working voltage to the voltage detection unit 302, the current detection unit 303, and the fault latching unit 304, respectively, so as to Figure 3 For a clearer description, Figure 3 Only the power supply unit 301 outputs the board working voltage to the current detection unit 303.

[0063] The voltage detection unit 302 is configured to detect the voltage of the load bus of the battery system to be tested and generate a voltage state signal, and send the voltage state signal to the fault latching unit 304; if the voltage does not exceed the voltage threshold, an enable valid signal is sent to the current detection unit 303.

[0064] The voltage state signal can include a voltage fault signal and a voltage non-fault signal. The voltage fault signal is generated when the voltage is higher than the voltage threshold. The voltage non-fault signal is generated when the voltage is lower than the voltage threshold.

[0065] The enable valid signal is used to enable the current detection unit 303 to work and start detecting the current of the load loop.

[0066] Due to the characteristic of the load loop with a capacitive load, the capacitive load is generally a load with a capacitive parameter, which can be represented by the load loop capacitance CL in the following formula: Figure 2 In the process of fast power-on and power-off of the battery system, there may be a situation that after power-off, the capacitive load is not completely discharged and is powered on again.

[0067] In one implementation scenario, the load loop capacitance CL has a voltage, i.e., after the battery system positive relay K1 and the battery system negative relay K2 are disconnected, but are soon closed again, resulting in that the load loop capacitance CL is not completely discharged and has a certain voltage, so that there is a voltage between the load bus and the load relay K3 contact. At this time, the voltage detection unit 302 can be used to detect the voltage between the load bus. If the detected voltage is lower than the voltage threshold, it indicates that the load loop is open circuit, i.e., the load relay K3 contact does not stick. If the detected voltage is higher than the voltage threshold, it indicates that the load loop is a closed circuit, i.e., the load relay K3 contact sticks. At this time, only the corresponding voltage state signal needs to be sent to the fault latching unit 304, and the current of the load loop does not need to be detected.

[0068] The current detection unit 303 is configured to receive the enable valid signal, detect the current of the load loop, and generate a current state signal, and send the current state signal to the fault latching unit 304.

[0069] After the current detection unit 303 receives the enable valid signal, it can start to work and detect the current of the load loop. In one possible implementation, the current state signal can also be generated according to the size relationship between the current and the current threshold, and the current state signal includes a current fault signal and a current non-fault signal.

[0070] In an implementation scenario, when the battery system positive relay K1 and the battery system negative relay K2 are disconnected and not closed in time, the load loop capacitor CL is fully discharged, and there is no voltage, i.e., there is no voltage across the load bus and no voltage across the load relay K3 contacts. At this time, the voltage detection unit 302 detects the voltage of the load bus, and the voltage is 0 or lower than the voltage threshold, so it is impossible to determine whether the load relay K3 contacts are stuck. At this time, the current detection unit 303 can be started to detect the current of the load loop. If the current is higher than the voltage threshold, it indicates that the load loop is in a closed state, i.e., the load relay K3 contacts are stuck. If the current is lower than the voltage threshold, it indicates that the load loop is in an open state, i.e., the load relay K3 contacts are not stuck.

[0071] The fault latching unit 304 is configured to receive the voltage state signal and the current state signal, and determine the detection result of the relay contact fault according to the voltage state signal and the current state signal.

[0072] In an implementation scenario, the fault latching unit 304 is specifically configured to: if the voltage state signal is the voltage non-fault signal and the current state signal is the current non-fault signal, determine that the detection result of the relay contact fault is a normal state.

[0073] If the voltage state signal is the voltage fault signal or the current state signal is the current fault signal, it is determined that the detection result of the relay contact fault is a fault state. For example, the fault latching unit 304 receives the voltage fault signal, or the voltage non-fault signal and the current fault signal, and can determine that the detection result of the relay contact fault is the fault state.

[0074] The embodiment of the present application provides a relay fault detection device of a battery system, a power supply unit 301 supplies power for a voltage detection unit 302, a current detection unit 303 and a fault latch unit 304. The voltage detection unit 302 detects the voltage of a load bus and generates a voltage state signal, and sends the voltage state signal to the fault latch unit 304. Meanwhile, it is also judged whether the voltage of the load bus is higher than a voltage threshold value, if the voltage does not exceed the voltage threshold value, an enable valid signal is sent to the current detection unit 303, so that the current detection unit 303 detects the current of a load loop and generates a current state signal, and sends the current state signal to the fault latch unit 304. The fault latch unit 304 determines the detection result of the relay contact fault according to the received voltage state signal and current state signal. The relay fault detection device of the battery system provided by the present application can detect the voltage of the load bus by the voltage detection unit 302 in the case that there is voltage between the load relay contacts, and can also detect the current of the load loop by the current detection unit 303 in the case that there is no voltage between the load relay contacts, and judges whether the load relay contacts are stuck according to the voltage and the current, so that the accuracy is improved, and the safety of the battery system is improved.

[0075] On the basis of the above embodiment, a specific embodiment is provided below, and the relay fault detection device of the battery system is introduced in detail.

[0076] Figure 4 A relay fault detection device of a battery system provided by the embodiment of the present application is shown Figure 2 . As shown in Figure 4 , the relay fault detection device of the battery system can include a power supply unit 301, a voltage detection unit 302, a current detection unit 303 and a fault latch unit 304, wherein the current detection unit 303 can include an excitation source circuit 3031 and a current detection circuit 3032.

[0077] The voltage detection unit 302 detects the voltage of the load bus and judges whether the voltage is higher than a voltage threshold value. If the voltage is higher than the voltage threshold value, a voltage fault signal is generated. If the voltage is lower than the voltage threshold value, a voltage non-fault signal is generated. The voltage fault signal and the voltage non-fault signal both belong to the voltage state signal. For example, the voltage fault signal can be "1", and the voltage non-fault signal can be "0".

[0078] When the voltage does not exceed the voltage threshold value, that is, the voltage non-fault signal "0" is generated, the voltage detection unit 302 sends the voltage non-fault signal "0" to the fault latch unit 304, and also sends an enable valid signal to the excitation source circuit 3031 and the current detection circuit 3032 respectively, so that the excitation source circuit 3031 and the current detection circuit 3032 start to work.

[0079] The excitation source circuit 3031 receives the enable signal and outputs an excitation signal to the load bus. The current detection circuit 3032 receives the enable signal, detects the current of the load loop, and determines whether the current is higher than a current threshold. If the current is higher than the current threshold, a current fault signal is generated. If the current is lower than the current threshold, a current non-fault signal is generated.

[0080] The current fault signal and the current non-fault signal both belong to the current state signal. For example, the current fault signal can be "1", and the current non-fault signal can be "0".

[0081] The excitation source circuit 3031 applies an excitation signal to the load bus. In one implementation scenario, the excitation signal can be a voltage signal, which is used to provide voltage for the load loop, so that the load loop generates current, and then the current detection circuit can be used to detect the current of the load loop.

[0082] After the current detection circuit 3032 generates the current state signal, the current state signal can be sent to the fault latching unit 304. The fault latching unit 304 determines the detection result of the relay contact fault according to the voltage state signal and the current state signal, and then sends the detection result of the relay contact fault to the battery management system, so that the battery management system controls the output end of the battery. If the voltage output by the output end is higher than the set threshold.

[0083] The battery output end is controlled, that is, the battery system positive relay and the battery system negative relay are controlled. In one implementation scenario, if the detection result of the relay contact fault is normal, the battery management system can close the battery system positive relay K1 and the battery system negative relay K2 to control the battery high-voltage output.

[0084] In another implementation scenario, if the detection result of the relay contact fault is a fault state, the battery system positive relay K1 and the battery system negative relay K2 are not closed, and the battery high-voltage output is terminated.

[0085] The embodiment of the present application provides a relay fault detection device of a battery system. A voltage detection unit 302 detects the voltage of a load bus, and judges whether the voltage is higher than a voltage threshold. If the voltage is higher than the voltage threshold, a voltage fault signal is generated, and the voltage fault signal is sent to a fault latching unit 304. If the voltage does not exceed the voltage threshold, a voltage non-fault signal is generated, and the voltage fault signal is sent to the fault latching unit 304, and an enable valid signal is sent to an excitation source circuit 3031 and a current detection circuit 3032 respectively. After the excitation source circuit 3031 receives the enable valid signal, an excitation signal is output to the load bus. After the current detection circuit 3032 receives the enable valid signal, the current of the load loop can be detected, and it is judged whether the current is higher than a current threshold. If the current is higher than the current threshold, a current fault signal is generated, and the current fault signal is sent to the fault latching unit 304. If the current is lower than the current threshold, a current non-fault signal is generated, and the current non-fault signal is sent to the fault latching unit 304. The fault latching unit 304 determines the detection result of the relay contact fault according to the received voltage state signal and the current state signal, and sends the detection result of the relay contact fault to a battery management system, and the battery management system can control the high-voltage output of the battery according to the detection result of the relay contact fault. The relay fault detection device of the battery system provided by the embodiment of the present application can judge whether the load relay contact is stuck through voltage and current in the case that there is voltage or no voltage between the load relay contacts, the accuracy is improved, and the safety of the battery system is improved.

[0086] On the basis of the above embodiment, the process of detecting the relay fault detection device of the battery system is described.

[0087] Figure 5 A battery system relay fault detection method flow provided by the embodiment of the present application Figure 1 The method can be executed by the relay fault detection device of the battery system, as shown in the figure, and the method is specifically as follows. Figure 5

[0088] S501: receiving the voltage sent by the battery management system, and the voltage is used to provide power for the relay fault detection device of the battery system.

[0089] The battery management system is a system for intelligently managing and maintaining each battery unit. The voltage output by the battery management system to the relay fault detection device is usually a low voltage, for example, 12V or 24V. After the relay fault detection device receives the voltage, the relay fault detection device starts to work.

[0090] S502: detecting the voltage of the load bus and generating a voltage state signal.

[0091] ​The voltage status signal can include a voltage fault signal and a voltage non-fault signal. In one implementation scenario, the voltage of the load bus is detected, and it is determined whether the voltage is higher than a voltage threshold. If the voltage is higher than the voltage threshold, the voltage fault signal is generated; if the voltage is lower than the voltage threshold, the voltage non-fault signal is generated. For example, the voltage fault signal can be "1", and the voltage non-fault signal can be "0".

[0092] In one implementation scenario, the load loop capacitor CL has a voltage, i.e., there is a voltage across the load bus and across the load relay K3 contact, and at this time the voltage detection unit 302 can be used to detect the voltage across the load bus. If the detected voltage is lower than the voltage threshold, it indicates that the load loop is open, i.e., the load relay K3 contact does not stick. If the detected voltage is higher than the voltage threshold, it indicates that the load loop is closed, i.e., the load relay K3 contact sticks, and at this time only the corresponding voltage status signal needs to be sent to the fault latching unit 304, and there is no need to detect the current of the load loop.

[0093] S503: If the voltage does not exceed the voltage threshold, the current of the load loop is detected and a current status signal is generated.

[0094] The current status signal includes a current fault signal and a current non-fault signal. In one implementation scenario, the current of the load loop is detected, and it is determined whether the current value is higher than a current threshold. If the current is higher than the current threshold, the current fault signal is generated. If the current is lower than the current threshold, the current non-fault signal is generated. For example, the current fault signal can be "1", and the current non-fault signal can be "0".

[0095] In one implementation scenario, if the load loop capacitor CL does not have a voltage, i.e., there is no voltage across the load bus and across the load relay K3 contact, at this time the voltage detected by the voltage detection unit 302 cannot determine whether the load relay K3 contact sticks, and therefore the current detection unit 303 can be started to detect the current of the load loop. If the current is higher than the voltage threshold, it indicates that the load loop is closed, i.e., the load relay K3 contact sticks. If the current is lower than the voltage threshold, it indicates that the load loop is open, i.e., the load relay K3 contact does not stick.

[0096] S504: A detection result of the relay contact fault is generated according to the voltage status signal and the current status signal.

[0097] In one implementation scenario, if the voltage status signal is the voltage fault signal and the current status signal is the current non-fault signal, it is determined that the detection result of the relay contact fault is a normal state. For example, the voltage status signal and the current status signal are both "0", indicating that the relay contact does not stick, and the detection result of the relay contact fault is the normal state, which can also be represented by "0".

[0098] In another implementation scenario, if the voltage state signal is a voltage fault signal or the current state signal is a current fault signal, the detection result of the relay contact fault is determined as a fault state. For example, the voltage state signal is "1", or the voltage state signal is "0" and the current state signal is "1", it can be determined that the relay contact is stuck, and thus the detection result of the relay contact fault is a fault state, which can also be represented by "1".

[0099] It should be noted that when the voltage state signal is "1", the current of the load loop does not need to be detected.

[0100] The embodiment of the present application provides a battery system load relay contact fault detection method, which receives a voltage sent by a battery management system, and the voltage is used to provide power for a relay fault detection device of the battery system. After the relay fault detection device is started, the voltage of a load bus is detected and a voltage state signal is generated, and if the voltage does not exceed a voltage threshold, the current of a load loop is detected and a current state signal is generated. The detection result of the relay contact fault is generated according to the voltage state signal and the current state signal. The method provided by the present application can effectively detect whether the load relay contact is stuck in the case that there is voltage or no voltage between the load relay, and the detection result of the relay contact fault is determined according to the voltage of the load bus and the current of the load loop, so that the accuracy is improved, and the safety of the battery system is improved.

[0101] To realize the protection of the positive and negative relays of the battery system, the battery management system and the relay fault detection device need to have certain timing and logic cooperation. Therefore, based on the above embodiment, the process of interaction between the battery management system and the relay fault detection device of the battery system is described in detail.

[0102] Figure 6 A battery system relay fault detection method provided by the embodiment of the present application Figure 2 As shown in Figure 6 The method can include the following steps.

[0103] S601: The battery management system receives a battery high-voltage output instruction.

[0104] The battery pack includes a battery and a battery management system. The battery can include a plurality of battery monomers. When the battery management system receives the battery high-voltage output instruction, the relay fault detection process is started, so as to avoid false triggering.

[0105] S602: The battery management system outputs a low voltage to the relay fault detection device to start the relay fault detection device for detection.

[0106] The low voltage outputted by the battery management system to the relay fault detection device can be 12V or 24V, and the relay fault detection device is powered by the low voltage.

[0107] S603: The relay fault detection device detects whether the load relay contact is stuck, and returns the detection result of the relay contact fault to the battery management system.

[0108] The relay fault detection device can detect the voltage of the load bus, and if the voltage is normal, the current of the load circuit can be further detected. The specific detection process can refer to the above embodiment, and the present application will not be described here.

[0109] The detection result of the relay contact fault can include two results of normal state and fault state. In one implementation scenario, the fault state can be represented by "1", and the normal state is represented by "0".

[0110] S604: The battery management system judges whether the detection result of the relay contact fault is the fault state. If not, step S605 is performed. If yes, step S606 is performed.

[0111] S605: Perform high voltage output of the battery.

[0112] If the detection result of the relay contact fault is the normal state, that is, the relay contact is not stuck, the battery system positive relay K1 and the battery system negative relay K2 can be closed at this time, and the battery is controlled to perform high voltage output.

[0113] S606: Terminate the high voltage output of the battery.

[0114] In another implementation scenario, if the detection result of the relay contact fault is the fault state, that is, the relay contact is stuck, the battery system positive relay K1 and the battery system negative relay K2 are prohibited to be closed, the high voltage output of the battery is terminated, and the fault is reported at the same time.

[0115] The embodiment of the present application provides a relay fault detection method. The battery management system receives a battery high voltage output instruction, outputs a low voltage to the relay fault detection device, and starts the relay fault detection device to perform detection. The relay fault detection device detects whether the load relay contact is stuck, and returns the detection result of the relay contact fault to the battery management system. The battery management system controls the high voltage output of the battery according to the detection result of the relay contact fault. If it is normal, the high voltage output is performed. If it is a fault state, the high voltage output is terminated. The method provided by the embodiment of the present application realizes the detection of the load relay contact through the interaction of the battery management system and the relay fault detection device, and improves the safety of the battery system.

[0116] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0117] It is to be understood that the application is not limited to the precise construction herein disclosed and shown in the drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the claims that follow.

Claims

1. A relay failure detection device of a battery system, characterized by, The method comprises the following steps: A power supply unit, a voltage detection unit, a current detection unit and a fault latching unit are provided; The power supply unit is configured to supply power to the voltage detection unit, the current detection unit and the fault latching unit; The voltage detection unit is configured to detect the voltage of a load bus of a battery system to be tested and generate a voltage state signal, and send the voltage state signal to the fault latching unit; if the voltage does not exceed a voltage threshold, an enable signal is sent to the current detection unit; wherein the voltage detection unit detects the voltage of the load bus before the positive and negative relays of the battery system are attracted; The current detection unit is configured to receive the enable signal, detect the current of the load loop and generate a current state signal, and send the current state signal to the fault latching unit; The current state signal comprises a current fault signal and a current non-fault signal; the current detection unit comprises a current detection circuit and an excitation source circuit; the current detection unit is specifically configured to: The excitation source circuit is configured to receive the enable signal and output an excitation signal to the load bus; The current detection circuit is configured to receive the enable signal, detect the current of the load loop, and determine whether the current is higher than a current threshold; If the current is higher than the current threshold, the current fault signal is generated; If the current is lower than the current threshold, the current non-fault signal is generated; The fault latching unit is configured to receive the voltage state signal and the current state signal, and determine the detection result of the load relay contact fault according to the voltage state signal and the current state signal.

2. The apparatus of claim 1, wherein, The voltage state signal comprises a voltage fault signal and a voltage non-fault signal; the voltage detection unit is specifically configured to: The voltage detection unit detects the voltage of the load bus, and determines whether the voltage is higher than the voltage threshold; If the voltage is higher than the voltage threshold, the voltage fault signal is generated; If the voltage is lower than the voltage threshold, the voltage non-fault signal is generated.

3. The apparatus of claim 2, wherein, The fault latching unit is specifically configured to: If the voltage state signal is the voltage non-fault signal and the current state signal is the current non-fault signal, it is determined that the detection result of the relay contact fault is normal; If the voltage state signal is the voltage fault signal or the current state signal is the current fault signal, it is determined that the detection result of the relay contact fault is a fault state.

4. The apparatus of claim 3, wherein, The fault latching unit is further configured to: Send the detection result of the relay contact fault to a battery management system, so that the battery management system controls the output end of the battery, and the voltage output by the output end is higher than a set threshold.

5. The apparatus of claim 4, wherein, The power supply unit is specifically configured to: The power supply unit receives the voltage output by the battery management system, and outputs a board card working voltage, which is used to supply power to the voltage detection unit, the current detection unit and the fault latching unit.

6. A method of detecting a relay failure of a battery system, characterized by, The method comprises the following steps: Receive the voltage sent by the battery management system, and the voltage is used to provide power for the relay fault detection device of the battery system; detecting a voltage of a load bus and generating a voltage status signal; wherein the voltage of the load bus is detected before positive and negative relays of the battery system are attracted; if the voltage does not exceed a voltage threshold, detecting a current of a load loop and generating a current status signal; the current status signal comprises a current fault signal and a current non-fault signal; the detecting the current of the load loop and generating the current status signal comprises: detecting the current of the load loop and determining whether the current is higher than a current threshold; if the current is higher than the current threshold, generating the current fault signal; if the current is lower than the current threshold, generating the current non-fault signal; generating a detection result of a load relay contact fault according to the voltage status signal and the current status signal.

7. The method of claim 6, wherein, the voltage status signal comprises a voltage fault signal and a voltage non-fault signal; the detecting the voltage of the load bus and generating the voltage status signal comprises: detecting the voltage of the load bus and determining whether the voltage is higher than a voltage threshold; if the voltage is higher than the voltage threshold, generating the voltage fault signal; if the voltage is lower than the voltage threshold, generating the voltage non-fault signal.

8. The method of claim 7, wherein, the generating the detection result of the relay contact fault according to the voltage status signal and the current status signal comprises: if the voltage status signal is the voltage non-fault signal and the current status signal is the current non-fault signal, determining that the detection result of the relay contact fault is a normal state; if the voltage status signal is the voltage fault signal or the current status signal is the current fault signal, determining that the detection result of the relay contact fault is a fault state.

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