Operating state detection method and detection circuit for relay in battery system

Abstract

Disclosed in the present application are an operating state detection method and detection circuit for a relay in a battery system. The method comprises: applying a first voltage to a first end of a relay and applying a second voltage to a second end of the relay; switching the operating state of a high-side driver connected in series at the first end and the operating state of a low-side driver connected in series at the second end to a disconnected state; and acquiring a third voltage corresponding to the first end and a fourth voltage corresponding to the second end, so as to acquire an operating state detection result for the relay on the basis of the third voltage and the fourth voltage. Thus, the accuracy of state detection is improved.

Description

Method and circuit for detecting working state of relay in battery system

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Chinese Patent Application No. 202411340264.1, filed September 24, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of circuit fault detection, in particular to a method and circuit for detecting the working state of a relay in a battery system. BACKGROUND

[0004] With the development of technology, in order to solve the pollution problem caused by internal combustion engine vehicles, vehicles using batteries as power sources to drive electric motors to obtain power have gradually become the tools for people to travel, among which fully electric vehicles can completely solve the pollution of internal combustion engine vehicles, and hybrid vehicles can improve fuel economy while also improving power to bring better user experience.

[0005] In the prior art of designing a battery system using a battery as a power source, a relay is widely used as a switching device for directly connecting the battery and the motor to supply energy. The relay, as a switching device for directly connecting the battery and the motor to supply energy, can not only provide power for the vehicle but also ensure that the battery is in a safe operating state, so it is very important to confirm the state of the relay.

[0006] The existing battery system often only arranges a relay at the positive terminal of the battery pack, and the other end of the relay is connected to the motor to supply energy from the battery to the motor. In the state detection of the relay in the battery system, the prior art detects the state of the high-side driver or low-side driver by measuring the output voltage of the high-side driver or low-side driver, and then detects the state of the relay. However, this detection method cannot accurately locate whether the relay drive circuit is disconnected or the high-side driver or low-side driver is short-circuited, and cannot accurately locate the type of fault. Further, if the motor capacitor is not discharged in time during the detection process, the voltage across the relay cannot accurately identify whether the relay is in a closed state or the motor capacitor has not been discharged, or the relay state is incorrect due to interference caused by the motor during startup or stop.

[0007] SUMMARY

[0008] To solve the above technical problems, the present application discloses a method and circuit for detecting the working state of a relay in a battery system, which improves the accuracy of relay state detection.

[0009] To achieve the above object, the application discloses a working state detection method of a relay in a battery system, comprising:

[0010] applying a first voltage to a first end of the relay and a second voltage to a second end of the relay;

[0011] switching the working state of the high-side driver in series with the first end and the low-side driver in series with the second end to an off state;

[0012] obtaining a third voltage corresponding to the first end and a fourth voltage corresponding to the second end, so as to obtain a working state detection result of the relay according to the third voltage and the fourth voltage.

[0013] The working state detection method of the relay in the battery system disclosed by the application first applies a first voltage and a second voltage to two ends of the relay respectively, and switches the working state of the driver to an off state, thereby excluding the influence of the driver on the fault detection of the relay, and then detects the working state of the relay by collecting the third voltage and the fourth voltage at the two ends of the relay. Wherein, by excluding the influence of the driver on the relay state detection, the accuracy of the working state detection result of the relay is improved.

[0014] As a preferred example, the working state detection result of the relay according to the third voltage and the fourth voltage comprises:

[0015] when the third voltage and the fourth voltage are consistent, a fifth voltage is applied to the second end of the relay;

[0016] obtaining a sixth voltage corresponding to the first end of the relay and a seventh voltage corresponding to the second end of the relay;

[0017] when the sixth voltage and the seventh voltage are consistent, it is determined that the relay has a sticking fault.

[0018] When it is determined that the third voltage and the fourth voltage are consistent, in order to exclude the interference of the motor capacitor on the relay state detection, the sixth voltage and the seventh voltage at the two ends of the relay are collected after the fifth voltage is applied to the relay, so as to accurately identify whether the relay has a sticking fault or the motor capacitor interferes with the fault detection of the relay by comparing the sixth voltage and the seventh voltage, thereby improving the accuracy of the relay detection.

[0019] As a preferred example, the working state detection result of the relay according to the third voltage and the fourth voltage comprises:

[0020] acquire a first high-side voltage corresponding to the high-side driver and a first low-side voltage corresponding to the low-side driver when the sixth voltage and the seventh voltage are inconsistent;

[0021] acquire a comparison result of the first high-side voltage and the first voltage and a comparison result of the first low-side voltage and the first voltage;

[0022] acquire a comparison result of the first low-side voltage and the second voltage when the first high-side voltage is consistent with the first voltage and the first low-side voltage is inconsistent with the first voltage;

[0023] determine that the connection of the high-side driver and the relay has an open circuit fault and the connection of the low-side driver and the relay has an open circuit fault when the first low-side voltage is consistent with the second voltage.

[0024] The application acquires voltage data at both ends of the high-side driver and the low-side driver and compares the voltage data with the first voltage and the second voltage applied to the relay respectively to determine whether the connection of the high-side driver, the low-side driver and the relay has an open circuit fault, so as to accurately locate the fault type when the relay fails, facilitating the fault repair of the relay later.

[0025] As a preferred example, the working state detection result of the relay according to the third voltage and the fourth voltage comprises:

[0026] acquire an output voltage corresponding to the high-side driver when the first high-side voltage is inconsistent with the first voltage and the first low-side voltage is inconsistent with the second voltage;

[0027] determine that the high-side driver has a short circuit fault when the first high-side voltage is consistent with the output voltage and the first low-side voltage is consistent with the output voltage.

[0028] After excluding the sticking fault of the relay, the application acquires a first high-side voltage and a first low-side voltage corresponding to the high-side driver and the low-side driver respectively connected at both ends of the relay under the current condition, and compares the first high-side voltage and the first low-side voltage with the output voltage of the high-side driver respectively to determine whether the high-side driver has a short circuit fault according to the comparison result, thereby realizing accurate positioning of the driver fault.

[0029] As a preferred example, the working state detection result of the relay according to the third voltage and the fourth voltage comprises:

[0030] acquiring a comparison result of the first high-side voltage and the first voltage and a first difference between the first low-side voltage and a preset voltage threshold when the first high-side voltage is inconsistent with the output voltage or the first low-side voltage is inconsistent with the output voltage;

[0031] determining that the low-side driver has a short circuit fault when the first high-side voltage is consistent with the first voltage and the first difference is within a preset tolerance threshold range.

[0032] The application excludes the short circuit fault of the high-side driver, and determines whether the low-side driver has a short circuit fault by judging whether the low-side voltage is close to the voltage threshold through acquiring a first difference between the low-side voltage and a preset voltage threshold, thereby realizing accurate positioning of the fault.

[0033] As a preferred example, the working state detection result of the relay is obtained according to the third voltage and the fourth voltage, including:

[0034] switching the working state of the high-side driver to a closed state when the first high-side voltage is consistent with the first voltage and the first low-side voltage is consistent with the first voltage;

[0035] acquiring a second high-side voltage corresponding to the high-side driver and a second low-side voltage corresponding to the low-side driver;

[0036] switching the working state of the low-side driver to a closed state when the second high-side voltage is consistent with the output voltage of the high-side driver and the second low-side voltage is consistent with the output voltage of the high-side driver;

[0037] acquiring a third low-side voltage corresponding to the low-side driver and a second difference between the third low-side voltage and a preset voltage threshold;

[0038] acquiring an eighth voltage corresponding to a first end of the relay and a ninth voltage corresponding to a second end of the relay when the second difference is within a preset tolerance threshold range;

[0039] determining that the relay cannot be closed when the eighth voltage is inconsistent with the ninth voltage.

[0040] The application excludes the short circuit fault of the driver, switches the working states of the high-side driver and the low-side driver to a closed state respectively, and acquires a second high-side voltage corresponding to the high-side driver and a second low-side voltage and a third low-side voltage corresponding to the low-side driver after the closed state, and then determines whether the relay has a fault of being unable to be closed, thereby realizing accurate positioning of the fault.

[0041] As a preferred example, the obtaining the working state detection result of the relay according to the third voltage and the fourth voltage comprises:

[0042] When the second difference is not within the preset tolerance threshold range, a first number of times when the third low-side voltage is consistent with the output voltage of the high-side driver within a preset time length is counted;

[0043] When the first number of times reaches a preset number threshold, it is determined that the low-side driver has an open circuit fault.

[0044] The application ensures the accuracy of the detection result of the open circuit fault of the low-side driver by continuously obtaining the third low-side voltage at a preset frequency within a preset time length and counting the first number of times when the third low-side voltage is consistent with the output voltage of the high-side driver.

[0045] As a preferred example, after the working state detection result of the relay is obtained according to the third voltage and the fourth voltage, the method comprises:

[0046] When the second high-side voltage is inconsistent with the output voltage of the high-side driver or the second low-side voltage is inconsistent with the output voltage of the high-side driver, a second number of times when the second high-side voltage is consistent with the first voltage within a preset time length and a third number of times when the second low-side voltage is consistent with the first voltage are counted;

[0047] When the second number of times reaches a preset number threshold and the third number of times reaches a preset number threshold, it is determined that the high-side driver has an open circuit fault.

[0048] After excluding the open circuit fault of the low-side driver, the application ensures the accuracy of the detection result of the open circuit fault of the high-side driver by continuously obtaining the second high-side voltage at a preset frequency within a preset time length and counting the second number of times when the second high-side voltage is consistent with the first voltage and the third number of times when the second low-side voltage is consistent with the first voltage.

[0049] In another aspect, the application discloses a working state detection circuit of a relay in a battery system, comprising a first voltage applying module, a second voltage applying module, a first voltage measuring module, a second voltage measuring module, and a state detection module.

[0050] The output end of the first voltage applying module is connected to the first end of the relay, the input end of the first voltage applying module is connected to the output end of the state detection module, and the state detection module is used to control the first voltage applying module to apply a first voltage to the first end of the relay.

[0051] The output end of the second voltage application module is connected to the second end of the relay, and the input end of the second voltage application module is connected to the output end of the state detection module, and the state detection module is further used for controlling the second voltage application module to apply a second voltage to the second end of the relay;

[0052] The output end of the state detection module is connected to the input end of the high-side driver connected in series to the first end of the relay, and is used for switching the working state of the high-side driver to an off state;

[0053] The output end of the state detection module is connected to the input end of the low-side driver connected in series to the second end of the relay, and is used for switching the working state of the low-side driver to an off state;

[0054] The input end of the first voltage measurement module is connected to the first end of the relay, and is used for acquiring a third voltage corresponding to the first end;

[0055] The input end of the second voltage measurement module is connected to the second end of the relay, and is used for acquiring a fourth voltage corresponding to the second end;

[0056] The output end of the first voltage measurement module and the output end of the second voltage measurement module are connected to the input end of the state detection module, and the third voltage and the fourth voltage are sent to the state detection module, and the state detection module is used for acquiring a working state detection result of the relay according to the third voltage and the fourth voltage.

[0057] The working state detection system of the relay in the battery system disclosed in the application first applies a first voltage and a second voltage to two ends of the relay respectively, and switches the working state of the driver to an off state, thereby excluding the influence of the driver on the relay fault detection, and then detects the working state of the relay by collecting a third voltage and a fourth voltage at the two ends of the relay. Wherein, by excluding the influence of the driver on the relay state detection, the accuracy of the working state detection result of the relay is improved.

[0058] As a preferred example, the high-side voltage measurement module and the low-side voltage measurement module are further included;

[0059] The input end of the high-side voltage measurement module is connected to the first end of the relay, and the output end of the high-side voltage measurement module is connected to the input end of the state detection module, and is used for acquiring a high-side voltage corresponding to the high-side driver and sending the high-side voltage to the state detection module;

[0060] The input end of the low-side voltage measurement module is connected to the second end of the relay, and the output end of the low-side voltage measurement module is connected to the input end of the state detection module, for acquiring the low-side voltage corresponding to the low-side driver and sending the low-side voltage to the state detection module.

[0061] The high-side voltage measurement module and the low-side voltage measurement module can accurately detect the state of the high-side driver and the low-side driver and the connection state of the high-side driver and the low-side driver and the relay, and thus accurately identify whether the high-side driver and the low-side driver in series with the relay are faulty.

[0062] As a preferred example, the fast discharge module and the slow discharge module are further included; the control end of the fast discharge module is connected to the state detection module, and the output end of the fast discharge module is connected to the second end of the relay; the control end of the slow discharge module is connected to the state detection module, and the output end of the slow discharge module is connected to the second end of the relay.

[0063] The fast discharge module is configured to apply a fifth voltage to the second end of the relay according to a preset fast voltage application mode.

[0064] The slow discharge module is configured to apply the fifth voltage to the second end of the relay according to a preset slow voltage application mode.

[0065] The discharge circuit with different discharge modes is provided to determine whether the relay is actually in a sticking fault or is disturbed by a motor capacitor, thereby improving the accuracy of fault identification.

[0066] As a preferred example, the first diode and the second diode are further included.

[0067] The anode of the first diode is connected to the output end of the first voltage application module, and the cathode of the first diode is connected to the first end of the relay.

[0068] The anode of the second diode is connected to the output end of the second voltage application module, and the cathode of the second diode is connected to the second end of the relay.

[0069] The first diode and the second diode are respectively arranged between the first voltage application module and the first end of the relay and between the second voltage application module and the second end of the relay, so that the two voltage application modules output current to the loop formed by the relay and the corresponding high-side voltage measurement module and low-side voltage measurement module, to measure the high-side voltage and the low-side voltage and detect the faults of the high-side driver and the low-side driver.

[0070] As a preferred example, the first voltage output by the first voltage application module is different from the second voltage output by the second voltage application module, and both the first voltage and the second voltage are less than the minimum coil actuation voltage of the relay.

[0071] The application sets the value of the output voltage of the voltage application module, so as to meet the requirements of the relay detection and improve the accuracy of the detection. BRIEF DESCRIPTION OF DRAWINGS

[0072] Fig. 1 is a flowchart of a method for detecting the working state of a relay in a battery system according to an embodiment of the application;

[0073] Fig. 2 is a structural diagram of a detection circuit for detecting the working state of a relay in a battery system according to an embodiment of the application;

[0074] Fig. 3 is a structural diagram of a detection circuit applied in a battery system according to another embodiment of the application;

[0075] Fig. 4 is a flowchart of detecting the working state of a relay based on a detection circuit according to another embodiment of the application;

[0076] In the drawings: 201, first voltage measurement module; 202, first voltage application module; 203, second voltage application module; 204, high-side voltage measurement module; 205, low-side voltage measurement module; 206, second voltage measurement module; 207, third voltage application module; 208, state detection module; 2041, first high-side voltage measurement module; 2042, second high-side voltage measurement module; 2051, first low-side voltage measurement module; 2052, second low-side voltage measurement module; 301, battery pack; 302, relay; 303, high-side driver; 304, low-side driver; 305, motor; 306, motor capacitor; 307, battery pack voltage measurement circuit; 308, first power supply; 309, second power supply; 310, first high-side voltage measurement circuit; 311, second high-side voltage measurement circuit; 312, first low-side voltage measurement circuit; 313, second low-side voltage measurement circuit; 314, battery pack external terminal voltage measurement circuit; 315, discharging module; 316, processor; 317, first diode; 318, second diode. DETAILED DESCRIPTION

[0077] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0078] Embodiment one

[0079] The embodiment discloses a method for detecting the working state of a relay in a battery system. The specific implementation process of the detection method is shown in FIG. 1, mainly including steps 101 to 103, which are mainly as follows:

[0080] Step 101: applying a first voltage to the first end of the relay and a second voltage to the second end of the relay.

[0081] Step 102: switching the working state of the high-side driver in series with the first end and the low-side driver in series with the second end to the off state.

[0082] Step 103: obtaining a third voltage corresponding to the first end and a fourth voltage corresponding to the second end, and obtaining a working state detection result of the relay according to the third voltage and the fourth voltage.

[0083] In some embodiments of the embodiment, when obtaining the working state detection result of the relay, it is necessary to determine whether the relay itself fails or the high-side driver or low-side driver connected to the relay fails. Based on this, first, it is detected whether the relay itself fails, and the detection of the failure is performed by detecting the sticking failure and the closing failure of the relay through the voltages at both ends of the relay. Specifically, the step 103 includes judging whether the relay has a sticking failure, and the determination process of the sticking failure includes the following steps:

[0084] Step S1: when the third voltage and the fourth voltage are consistent, applying a fifth voltage to the second end of the relay.

[0085] Step S2: obtaining a sixth voltage corresponding to the first end of the relay and a seventh voltage corresponding to the second end of the relay.

[0086] Step S3: when the sixth voltage and the seventh voltage are consistent, it is determined that the relay has a sticking failure.

[0087] In the steps S1 to S3, when it is determined that the third voltage and the fourth voltage are consistent, in order to exclude the interference of the motor capacitor on the relay state detection, the sixth voltage and the seventh voltage at both ends of the relay are collected after the fifth voltage is applied to the relay, and then the sixth voltage and the seventh voltage are compared to accurately identify whether the relay has a sticking failure or the motor capacitor interferes with the failure detection of the relay, thereby improving the accuracy of the relay detection.

[0088] In some embodiments of the present embodiment, in the detection of the sticking fault of the relay, if the third voltage and the fourth voltage are inconsistent, it can be determined that the relay has no sticking fault. However, when the third voltage and the fourth voltage are inconsistent, it cannot be determined whether the relay is in a normal open state, and therefore the connection between the high-side driver, the low-side driver and the relay needs to be detected. Specifically, the process of detecting the connection between the driver and the relay includes the following steps:

[0089] Step S4: When the sixth voltage and the seventh voltage are inconsistent, the first high-side voltage corresponding to the high-side driver and the first low-side voltage corresponding to the low-side driver are collected.

[0090] Step S5: The comparison results of the first high-side voltage and the first voltage and the first low-side voltage and the first voltage are obtained.

[0091] Step S6: When the first high-side voltage and the first voltage are consistent and the first low-side voltage and the first voltage are inconsistent, the comparison result of the first low-side voltage and the second voltage is obtained.

[0092] Step S7: When the first low-side voltage and the second voltage are consistent, it is determined that the connection between the high-side driver and the relay has an open circuit fault and the connection between the low-side driver and the relay has an open circuit fault.

[0093] In the steps S4 to S7, by obtaining the voltage data between the high-side driver and the low-side driver and comparing it with the first voltage and the second voltage applied to the relay respectively, it is determined whether the connection between the high-side driver, the low-side driver and the relay has an open circuit fault, so as to accurately locate the fault type when the relay fails, facilitating the fault repair of the relay later.

[0094] In some embodiments of the present embodiment, when the connection between the driver and the relay is detected for failure, if the prerequisite for the determination is not met, that is, the first high-side voltage is inconsistent with the first voltage and the first low-side voltage is inconsistent with the second voltage, then the high-side driver or the low-side driver may have a short circuit failure, and detection of the short circuit failure of the high-side driver and the low-side driver is performed. When the high-side driver and the low-side driver have a short circuit failure, the voltage across the high-side driver or the low-side driver approaches 0V, and at this time, the 0V can be set as a voltage threshold, and a small tolerance threshold range can be set to determine whether the voltage across the high-side driver or the low-side driver approaches 0V according to the tolerance threshold range. The process of detecting the short circuit failure includes the following steps:

[0095] Step S8: When the first high-side voltage is inconsistent with the first voltage and the first low-side voltage is inconsistent with the second voltage, the output voltage corresponding to the high-side driver is obtained.

[0096] Step S9: When the first high-side voltage is consistent with the output voltage and the first low-side voltage is consistent with the output voltage, it is determined that the high-side driver has a short circuit failure.

[0097] Step S10: When the first high-side voltage is inconsistent with the output voltage or the first low-side voltage is inconsistent with the output voltage, the comparison result of the first high-side voltage and the first voltage and the first difference value of the first low-side voltage and the preset voltage threshold are obtained.

[0098] Step S11: When the first high-side voltage is consistent with the first voltage and the first difference value is within the preset tolerance threshold range, it is determined that the low-side driver has a short circuit failure.

[0099] In the steps S8 to S11, after excluding the sticking failure of the relay, the first high-side voltage and the first low-side voltage corresponding to the high-side driver and the low-side driver connected across the relay under the current condition are collected, and the output voltage of the high-side driver is compared with the first high-side voltage and the first low-side voltage, respectively, to determine whether the high-side driver or the low-side driver has a short circuit failure according to the comparison result, thereby realizing accurate positioning of the driver failure.

[0100] Referring to the above steps S1 to S11, when the first voltage and the second voltage across the relay are consistent, the sticking failure of the relay, the short circuit failure of the driver, and the open circuit failure between the relay and the driver are detected one by one, thereby improving the accuracy of the state detection.

[0101] Further, in some embodiments of the present embodiment, when the first voltage and the second voltage at both ends of the relay are inconsistent, then first need to detect whether the relay has a failure of being unable to close. The detection process of the failure of being unable to close includes the following steps:

[0102] Step S12: When the first high-side voltage is consistent with the first voltage and the first low-side voltage is consistent with the first voltage, switch the working state of the high-side driver to a closed state;

[0103] Step S13: Obtain the second high-side voltage corresponding to the high-side driver and the second low-side voltage corresponding to the low-side driver;

[0104] Step S14: When the second high-side voltage is consistent with the output voltage of the high-side driver and the second low-side voltage is consistent with the output voltage of the high-side driver, switch the working state of the low-side driver to a closed state;

[0105] Step S15: Collect the third low-side voltage corresponding to the low-side driver, and obtain a second difference between the third low-side voltage and a preset voltage threshold;

[0106] Step S16: When the second difference is within a preset tolerance threshold range, obtain an eighth voltage corresponding to the first end of the relay and a ninth voltage corresponding to the second end of the relay;

[0107] Step S17: When the eighth voltage is inconsistent with the ninth voltage, determine that the relay is unable to close.

[0108] In the steps S12 to S17, after excluding the short circuit failure of the driver, the working states of the high-side driver and the low-side driver are switched to a closed state respectively, and the second high-side voltage corresponding to the high-side driver and the second low-side voltage and the third low-side voltage corresponding to the low-side driver after the closed state are collected, so as to judge whether the relay has a failure of being unable to close, and realize accurate positioning of the failure.

[0109] In some embodiments of the present embodiment, when the relay does not have a failure of being unable to close, the second difference will not be within the tolerance threshold range (which is the same as the above-mentioned tolerance threshold range), then it is necessary to judge whether the low-side driver or the high-side driver has an open circuit failure, resulting in inconsistency between the first voltage and the second voltage. The detection process of the open circuit failure of the low-side driver or the high-side driver includes the following steps:

[0110] Step S18: When the second difference is not within the preset tolerance threshold, count a first number of times when the third low-side voltage is consistent with the output voltage of the high-side driver within a preset time length.

[0111] Step S19: When the first number of times reaches a preset number threshold, determine that the low-side driver has an open-circuit fault.

[0112] Step S20: When the second high-side voltage is inconsistent with the output voltage of the high-side driver or the second low-side voltage is inconsistent with the output voltage of the high-side driver, count a second number of times when the second high-side voltage is consistent with the first voltage and a third number of times when the second low-side voltage is consistent with the first voltage within a preset time length.

[0113] Step S21: When the second number of times reaches a preset number threshold and the third number of times reaches a preset number threshold, determine that the high-side driver has an open-circuit fault.

[0114] After excluding various types of faults such as the sticking fault, the high-side driver short-circuit fault, or the low-side driver short-circuit fault in the relay through steps S1 to S17, when the third low-side voltage is consistent with the output voltage of the high-side driver in steps S18 to S21, the steps S1 to S19 are repeatedly executed within a preset time length and the number of repetitions of the steps S1 to S19 is accumulated. When the third low-side voltage is consistent with the output voltage of the high-side driver in each repetition and the number of repetitions of the steps S1 to S19, i.e., the first number of times, reaches a preset number threshold, it is determined that the low-side driver has an open-circuit fault. Optionally, the number threshold is 8 times. Similarly, when the second high-side voltage is inconsistent with the output voltage of the high-side driver or the second low-side voltage is inconsistent with the output voltage of the high-side driver in steps S20 to S21, the steps S1 to S21 are repeatedly executed within a preset time length and the number of repetitions of the steps S1 to S21 is accumulated. When the second high-side voltage is consistent with the first voltage, the second low-side voltage is consistent with the first voltage, and the number of repetitions of the steps S1 to S21, i.e., the second number of times and the third number of times, reaches a preset number threshold (which is the same as the above number threshold) in each repetition, it is determined that the high-side driver has an open-circuit fault. The embodiment improves the accuracy of open-circuit fault detection of the high-side driver and the low-side driver by repeatedly performing the detection steps multiple times.

[0115] In another aspect, the embodiment also discloses a working state detection circuit of a relay in a battery system, and the specific structure of the detection circuit is shown in FIG. 2, which comprises a first voltage measurement module 201, a first voltage application module 202, a second voltage application module 203, a second voltage measurement module 206 and a state detection module 208.

[0116] Referring to FIG. 2, the output end of the first voltage application module 202 is connected to the first end of the relay, and the input end of the first voltage application module 202 is connected to the output end of the state detection module 208, and the state detection module 208 is used to control the first voltage application module 202 to apply a first voltage to the first end of the relay.

[0117] The output end of the second voltage application module 203 is connected to the second end of the relay, and the input end of the second voltage application module 203 is connected to the output end of the state detection module 208, and the state detection module 208 is also used to control the second voltage application module 203 to apply a second voltage to the second end of the relay.

[0118] The output end of the state detection module 208 is connected to the input end of a high-side driver connected in series to the first end of the relay, and is used to switch the working state of the high-side driver to an off state.

[0119] The output end of the state detection module 208 is connected to the input end of a low-side driver connected in series to the second end of the relay, and is used to switch the working state of the low-side driver to an off state.

[0120] The input end of the first voltage measurement module 201 is connected to the first end of the relay, and is used to obtain a third voltage corresponding to the first end.

[0121] The input end of the second voltage measurement module 206 is connected to the second end of the relay, and is used to obtain a fourth voltage corresponding to the second end.

[0122] The output end of the first voltage measurement module 201 and the output end of the second voltage measurement module 206 are connected to the input end of the state detection module 208, and the third voltage and the fourth voltage are sent to the state detection module 208, and the state detection module 208 is used to obtain a working state detection result of the relay according to the third voltage and the fourth voltage.

[0123] Referring to FIG. 2, the working state detection circuit further comprises a high-side voltage measurement module 204 and a low-side voltage measurement module 205; an input end of the high-side voltage measurement module 204 is connected to a first end of the relay, and an output end of the high-side voltage measurement module 204 is connected to an input end of the state detection module 208, for obtaining a high-side voltage corresponding to the first end of the relay and sending the high-side voltage to the state detection module 208; an input end of the low-side voltage measurement module 205 is connected to a second end of the relay, and an output end of the low-side voltage measurement module 205 is connected to an input end of the state detection module 208, for obtaining a low-side voltage corresponding to the second end of the relay and sending the low-side voltage to the state detection module 208.

[0124] Further, referring to FIG. 2, the high-side voltage measurement module 204 comprises a first high-side voltage measurement module 2041 and a second high-side voltage measurement module 2042, and the low-side voltage measurement module 205 comprises a first low-side voltage measurement module 2051 and a second low-side voltage measurement module 2052; input ends of the first high-side voltage measurement module 2041 and the second high-side voltage measurement module 2042 are connected to an output end of the high-side driver and to the first end of the relay, and output ends of the first high-side voltage measurement module 2041 and the second high-side voltage measurement module 2042 are connected to a second input end of the state detection module 208; input ends of the first low-side voltage measurement module 2051 and the second low-side voltage measurement module 2052 are connected to an output end of the low-side driver and to the second end of the relay, and output ends of the first low-side voltage measurement module 2051 and the second low-side voltage measurement module 2052 are connected to the second input end of the state detection module 208.

[0125] Referring to FIG. 2, the working state detection circuit further comprises a third voltage application module 207; the third voltage application module 207 comprises a fast discharge module and a slow discharge module; a control end of the fast discharge module is connected to the state detection module 208, and an output end of the fast discharge module is connected to the second end of the relay; a control end of the slow discharge module is connected to the state detection module 208, and an output end of the slow discharge module is connected to the second end of the relay; the fast discharge module is configured to apply a fifth voltage to the second end of the relay according to a preset fast voltage application mode; and the slow discharge module is configured to apply the fifth voltage to the second end of the relay according to a preset slow voltage application mode.

[0126] Referring to FIG. 3, the working state detection circuit further comprises a first diode and a second diode, an anode of the first diode is connected with an output end of the first voltage applying module 202, a cathode of the first diode is connected with a first end of the relay; an anode of the second diode is connected with an output end of the second voltage applying module 203, a cathode of the second diode is connected with a second end of the relay.

[0127] Further, in the embodiment, the first voltage output by the first voltage applying module 202 is different from the second voltage output by the second voltage applying module 203, and both the first voltage and the second voltage are less than the minimum coil actuation voltage of the relay.

[0128] In the above embodiment, the first voltage measuring module 201, the second voltage measuring module 206, the high-side driver, the high-side voltage measuring module 204, the first high-side voltage measuring module 2041, the second high-side voltage measuring module 2042, the low-side voltage measuring module 205, the first low-side voltage measuring module 2051, the second low-side voltage measuring module 2052 and the low-side driver can be one or more processors, controllers or chips with a communication interface capable of implementing a communication protocol, and can further include a memory and related interfaces, a system transmission bus, etc. if necessary; the processor, controller or chip executes program-related codes to realize corresponding functions. Alternatively, the first voltage measuring module 201, the second voltage measuring module 206, the high-side driver, the high-side voltage measuring module 204, the first high-side voltage measuring module 2041, the second high-side voltage measuring module 2042, the low-side voltage measuring module 205, the first low-side voltage measuring module 2051, the second low-side voltage measuring module 2052 and the low-side driver share an integrated chip or share a processor, controller, memory, etc. The shared processor, controller or chip executes program-related codes to realize corresponding functions.

[0129] Embodiment Two

[0130] The embodiment provides a battery system and a working state detection circuit of a relay. Specifically, when the working state detection circuit of the relay is applied to the battery system for detecting the state of the relay, the working state detection circuit is connected with the structure of the battery system. Please refer to FIG. 3, wherein, as shown in FIG. 3:

[0131] The battery system comprises a battery pack 301, a relay 302, a high-side driver 303, a low-side driver 304, a motor 305 and a motor capacitor 306.

[0132] The working state detection circuit comprises a battery pack voltage measurement circuit 307 (i.e. a first voltage measurement module), a first power supply 308 (i.e. a first voltage application module), a second power supply 309 (i.e. a second voltage application module), a first high-side voltage measurement circuit 310, a second high-side voltage measurement circuit 311, a first low-side voltage measurement circuit 312, a second low-side voltage measurement circuit 313, a battery pack external terminal voltage measurement circuit 314 (i.e. a second voltage measurement module), a discharging module 315, and a processor 316 (i.e. a state detection module).

[0133] Further, as shown in FIG. 3, in the battery system, the positive electrode of the battery pack 301 is connected to the first end of the relay 302, and the negative electrode of the battery pack 301 is connected to the second end of the motor 305 and the negative terminal of the motor capacitor 306. The output end of the high-side driver 303 is connected to the first end of the relay 302, and the output end of the low-side driver 304 is connected to the second end of the relay 302. Further, the second end of the relay 302 is connected to the first end of the motor 305 and the positive terminal of the motor capacitor 306. Optionally, referring to FIG. 3, the first end of the relay 302 is set as the first end of the coil in the relay, i.e. point A shown in FIG. 3, and the second end of the relay 302 is set as the second end of the coil in the relay, i.e. point B shown in FIG. 3.

[0134] Further, as shown in FIG. 3, the output end of the first power supply 308 is connected to the first end of the relay 302, and the control end of the first power supply 308 is connected to the first output end of the processor 316. The output end of the second power supply 309 is connected to the second end of the relay 302. The input end of the battery pack voltage measurement circuit 307 is connected to the first end of the relay 302, and the input end of the battery pack voltage measurement circuit 307 is also connected to the positive electrode of the battery pack 301. The output end of the battery pack voltage measurement circuit 307 is connected to the input end of the processor 316.

[0135] Referring to FIG. 3, the input end of the battery pack external terminal voltage measurement circuit 314 is connected to the second end of the relay 302, and the output end of the battery pack external terminal voltage measurement circuit 314 is connected to the input end of the processor 316.

[0136] Referring to FIG. 3, the output end of the discharging module 315 is connected to the second end of the relay 302, and the control end of the discharging module 315 is connected to the output end of the processor 316.

[0137] Referring to Fig. 3, the input terminals of the first high-side voltage measurement circuit 310 and the second high-side voltage measurement circuit 311 are connected to the first terminal of the relay 302, and the output terminals of the first high-side voltage measurement circuit 310 and the second high-side voltage measurement circuit 311 are connected to the input terminals of the processor 316. Further, referring to Fig. 3, the input terminals of the first high-side voltage measurement circuit 310 and the second high-side voltage measurement circuit 311 are also connected to the output terminals of the high-side driver 303.

[0138] Referring to Fig. 3, the input terminals of the first low-side voltage measurement circuit 312 and the second low-side voltage measurement circuit 313 are connected to the second terminal of the relay 302, and the output terminals of the first low-side voltage measurement circuit 312 and the second low-side voltage measurement circuit 313 are connected to the input terminals of the processor 316. Further, referring to Fig. 3, the input terminals of the first low-side voltage measurement circuit 312 and the second low-side voltage measurement circuit 313 are also connected to the output terminals of the low-side driver 304.

[0139] Referring to Fig. 3, the output terminals of the processor 316 are also connected to the control terminals of the high-side driver 303 and the low-side driver 304.

[0140] Further, referring to the schematic diagram of the detection circuit connected to the battery system shown in Fig. 3, the working state detection circuit can further be provided with a first diode 317 and a second diode 318. The anode of the first diode 317 is connected to the output terminal of the first power supply 308, and the cathode of the first diode 317 is connected to the first terminal of the relay 302. The anode of the second diode 318 is connected to the output terminal of the second power supply 309, and the cathode of the second diode 318 is connected to the second terminal of the relay 302.

[0141] Specifically, a constant-current fast discharge circuit and a constant-current slow discharge circuit can be provided in the discharge module 315. The control terminal of the discharge module 315 is connected to the output terminal of the processor 316. The processor 316 determines whether to start the discharge module according to the control logic of the relay 302.

[0142] In this embodiment, to ensure that the detection circuit is applicable to the state detection of the relay of the battery system, the output voltages of the first power supply 308 and the second power supply 309 are set to be inconsistent, and the output voltages of the first power supply 308 and the second power supply 309 are both less than the minimum pull-in operating voltage of the coil of the relay 302. Meanwhile, the load carrying capacity of the first power supply 308 and the second power supply 309 is greater than the current capacity required by the coil of the relay 302.

[0143] Further, to ensure the safety of the battery system and the detection circuit, one end of the battery pack voltage measurement circuit 307 is grounded, one end of the battery pack outer end voltage measurement circuit 314 is grounded, one end of the first high-side voltage measurement circuit 310, the second high-side voltage measurement circuit 311, the first low-side voltage measurement circuit 312, and the second low-side voltage measurement circuit 313 is grounded, one end of the low-side driver 304 is grounded, and one end of the processor 316 is grounded.

[0144] In an embodiment, the detection circuit shown in FIG. 3 is applied to detect the relay of the battery system, and the detection method can refer to FIG. 4. Specifically, the detection method includes steps 401 to 421, which are as follows:

[0145] Step 401: Initialize the processor, and the processor controls the first power supply and the second power supply to apply the first voltage and the second voltage to the relay, and switches the working state of the high-side driver and the low-side driver to the off state, and then collects the third voltage and the fourth voltage across the relay, so as to determine whether the relay is faulty.

[0146] In this embodiment, the step mainly includes: initializing the processor, and the processor controls the first power supply and the second power supply to output the first voltage and the second voltage and executes the instruction to turn off the high-side driver and the low-side driver, and then starts the battery pack voltage measurement circuit and the battery pack outer end voltage measurement circuit, and obtains the third voltage corresponding to the first end of the relay and the fourth voltage corresponding to the second end of the relay.

[0147] The processor determines whether the third voltage and the fourth voltage are consistent. If not, it is determined that the relay is in the off state. If they are consistent, it is determined that there is a possibility that the relay is closed, i.e., the relay may have a sticking fault, under the condition that the high-side driver and the low-side driver are turned off.

[0148] Step 402: The processor controls the discharge module to apply the fifth voltage to the relay, and then collects the sixth voltage and the seventh voltage across the relay, so as to determine whether the relay has a sticking fault.

[0149] In this embodiment, the step mainly includes: if the third voltage collected by the battery pack voltage measurement circuit and the fourth voltage collected by the battery pack outer end voltage measurement circuit are consistent, then the slow discharge circuit in the discharge module is started to apply the fifth voltage to the relay, and after a period of time, the voltage measurement of the battery pack voltage measurement circuit and the battery pack outer end voltage measurement circuit is performed again, and it is determined again whether the collected sixth voltage and the seventh voltage are consistent. If not, it is determined that the current relay is not a sticking fault, and the next step is directly entered, and it is indicated that there is external EMC interference leading to inaccurate voltage measurement.

[0150] After that, if the third voltage and the fourth voltage are consistent, a constant current fast discharge circuit in the discharge module is started for a period of time. After the constant current fast discharge is started, the battery pack voltage and the battery pack outside voltage are measured again, and it is determined whether the sixth voltage and the seventh voltage collected at this time are consistent. If they are consistent, it indicates that the relay sticking processor or the memory is faulty. If they are not consistent, it indicates that the capacitor of the external motor has charge and has not been discharged. At this time, the relay does not have a sticking fault.

[0151] Step 403: When it is determined that the relay does not have a sticking fault, the processor collects a first high-side voltage corresponding to the high-side driver and a first low-side voltage corresponding to the low-side driver, so as to determine whether the high-side driver and the low-side driver have a short circuit fault according to the first high-side voltage and the first low-side voltage.

[0152] In this embodiment, this step mainly includes that the processor starts voltage measurement of the first power supply and the second power supply, and voltage measurement of the high-side driver and the low-side driver.

[0153] Before the short circuit fault detection, the processor determines whether the first high-side voltage corresponding to the measurement of the high-side driver and the first low-side voltage corresponding to the measurement of the low-side driver are consistent with the first voltage output by the first power supply. If they are consistent, it is determined that the high-side driver and the low-side driver do not have a short circuit obstacle.

[0154] If they are not consistent, the processor determines whether the voltages measured by the first high-side voltage measurement circuit and the second high-side voltage measurement circuit are consistent. If they are not consistent, it indicates that the voltage measurement of the high-side driver has a fault, and the detection is performed again. If they are consistent, the processor determines whether the voltages measured by the first low-side voltage measurement circuit and the second low-side voltage measurement circuit are consistent. If they are not consistent, it indicates that the voltage measurement of the low-side driver has a fault, and the detection is performed again.

[0155] If they are consistent, the processor determines whether the first high-side voltage corresponding to the high-side driver is consistent with the first voltage output by the first power supply. At this time, the voltage drop of the diode is ignored, and it is determined whether the first low-side voltage corresponding to the low-side driver is consistent with the second voltage output by the second power supply. If they are consistent, it indicates that the high-low side driver and the relay connection have an open circuit fault.

[0156] If they are not consistent, the processor determines whether the first high-side voltage corresponding to the high-side driver is consistent with the voltage output by the high-side driver after the high-side driver is closed, and whether the first low-side voltage corresponding to the low-side driver is consistent with the voltage output by the high-side driver after the high-side driver is closed. If they are consistent, it indicates that the high-side driver has a short circuit fault.

[0157] If not consistent, the processor determines whether the first high-side voltage corresponding to the high-side driver is consistent with the first voltage output by the first power supply, at which time the diode voltage drop is ignored, and whether the first low-side voltage corresponding to the low-side driver is close to 0V; if the first high-side voltage corresponding to the high-side driver is consistent with the first voltage output by the first power supply, it indicates that the low-side driver has a short-circuit fault; if not consistent, it is determined that the high-side driver and the low-side driver do not have a short-circuit fault.

[0158] Step 404: The processor controls the high-side driver to be closed, and collects a second high-side voltage corresponding to the high-side driver and a second low-side voltage corresponding to the low-side driver, so as to determine whether the high-side driver has an open-circuit fault.

[0159] In this embodiment, the step mainly includes: the processor determines whether the second high-side voltage corresponding to the high-side driver is consistent with the second low-side voltage corresponding to the low-side driver and the voltage output after the high-side driver is closed; if consistent, it is determined that the high-side driver does not have an open-circuit fault,

[0160] If not consistent, the processor determines whether the second high-side voltage corresponding to the high-side driver is consistent with the second low-side voltage corresponding to the low-side driver and the first voltage output by the first power supply; if not consistent, the high-side driver is restarted to be closed, and the detection is restarted; if consistent, the processor determines that the second high-side voltage corresponding to the high-side driver is consistent with the second low-side voltage corresponding to the low-side driver and the first voltage output by the first power supply, and the cumulative number is 5 times, wherein the cumulative number or time can be adjusted appropriately; if satisfied, it indicates that the high-side driver has an open-circuit fault; if not satisfied, the high-side driver is detected again.

[0161] Step 405: The processor controls the low-side driver to be closed, and collects a third low-side voltage corresponding to the low-side driver, so as to determine whether the low-side driver has an open-circuit fault or the relay has a closed-circuit fault.

[0162] In this embodiment, the step specifically includes: the processor starts an instruction of closing the low-side driver, at which time the low-side driver is closed, the processor starts all voltage measurements, and the processor determines whether the third low-side voltage is close to 0V; when the third low-side voltage is not close to 0V, the third low-side voltage and the output voltage are compared; when the third low-side voltage and the output voltage are the same, the same time length is cumulatively calculated; when the time length reaches the time length threshold, it is determined that the low-side driver has the open-circuit fault.

[0163] When the third low-side voltage is close to 0V, the eighth voltage corresponding to the first end of the relay and the ninth voltage corresponding to the second end of the relay are collected, and the eighth voltage and the ninth voltage are compared; when the eighth voltage and the ninth voltage are the same, it is determined that the relay has been closed; when the eighth voltage and the ninth voltage are different, it is determined that the relay has a closing fault.

[0164] The detection circuit and the detection method disclosed by the embodiment can determine whether the relay is truly stuck or whether the relay state detection error is caused by the motor capacitor not being discharged or by interference. Meanwhile, two power supplies are output to the high-side and low-side drive output circuits through diodes; the state of the high-side and low-side drivers and the connection state of the high-side and low-side drivers and the relay can be accurately detected through the two redundant high-side voltage measurements and the two low-side voltage measurements, and the confidence of the high-side and low-side driver voltage measurements can be improved. The battery pack voltage and the battery external voltage are detected to identify whether the relay is effectively closed, and the relay state can be detected under the condition that the motor capacitor is not discharged, and the problem of relay state detection error caused by interference during motor starting or stopping can be solved, thereby improving the detection accuracy and accurately identifying each fault, facilitating product after-sales and maintenance.

[0165] In the above embodiment, the battery pack voltage measurement circuit 307, the high-side driver 303, the first high-side voltage measurement circuit 310, the second high-side voltage measurement circuit 311, the first low-side voltage measurement circuit 312, the second low-side voltage measurement circuit 313, the low-side driver 304, the battery pack external voltage measurement circuit 314, and the discharge module 315 can be one or more processors, controllers, or chips with a communication interface to implement a communication protocol, and can also include a memory and related interfaces, a system transmission bus, etc. if necessary; the processor, the controller, or the chip executes program-related codes to implement corresponding functions. Alternatively, the battery pack voltage measurement circuit 307, the high-side driver 303, the first high-side voltage measurement circuit 310, the second high-side voltage measurement circuit 311, the first low-side voltage measurement circuit 312, the second low-side voltage measurement circuit 313, the low-side driver 304, the battery pack external voltage measurement circuit 314, and the discharge module 315 share an integrated chip or share a processor, a controller, a memory, etc. The shared processor, the controller, or the chip executes program-related codes to implement corresponding functions.

[0166] The above-described specific embodiments, purposes, technical solutions and beneficial effects of the present application are further described in detail, and it should be understood that the above-described is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of detecting an operating state of a relay in a battery system, wherein, The method comprises: applying a first voltage to a first end of a relay and applying a second voltage to a second end of the relay; switching a working state of a high-side driver connected in series to the first end and a low-side driver connected in series to the second end to an open state; obtaining a third voltage corresponding to the first end and a fourth voltage corresponding to the second end to obtain a working state detection result of the relay according to the third voltage and the fourth voltage.

2. The method of claim 1, wherein the relay is a relay of a battery system. The working state detection result of the relay according to the third voltage and the fourth voltage comprises: applying a fifth voltage to the second end of the relay when the third voltage and the fourth voltage are consistent; obtaining a sixth voltage corresponding to the first end of the relay and a seventh voltage corresponding to the second end of the relay; determining that the relay has a sticking fault when the sixth voltage and the seventh voltage are consistent.

3. The method of claim 2, wherein the relay is a relay of a battery system. The working state detection result of the relay according to the third voltage and the fourth voltage comprises: when the sixth voltage and the seventh voltage are inconsistent, collecting a first high-side voltage corresponding to the high-side driver and a first low-side voltage corresponding to the low-side driver; obtaining a comparison result of the first high-side voltage and the first voltage and a comparison result of the first low-side voltage and the first voltage; when the first high-side voltage is consistent with the first voltage and the first low-side voltage is inconsistent with the first voltage, obtaining a comparison result of the first low-side voltage and the second voltage; when the first low-side voltage is consistent with the second voltage, determining that there is an open circuit fault in the connection between the high-side driver and the relay and an open circuit fault in the connection between the low-side driver and the relay.

4. The method of claim 3, wherein the relay is a relay of a battery system. The working state detection result of the relay according to the third voltage and the fourth voltage comprises: when the first high-side voltage is inconsistent with the first voltage and the first low-side voltage is inconsistent with the second voltage, obtaining an output voltage corresponding to the high-side driver; when the first high-side voltage is consistent with the output voltage and the first low-side voltage is consistent with the output voltage, determining that the high-side driver has a short circuit fault.

5. The method of claim 4, wherein the step of detecting the operating state of the relay includes the steps of: determining whether the relay is in the on state or the off state based on the voltage across the relay. The working state detection result of the relay according to the third voltage and the fourth voltage comprises: when the first high-side voltage is inconsistent with the output voltage or the first low-side voltage is inconsistent with the output voltage, obtaining a comparison result of the first high-side voltage and the first voltage and a first difference value of the first low-side voltage and a preset voltage threshold value; when the first high-side voltage is consistent with the first voltage and the first difference value is within a preset tolerance threshold range, determining that the low-side driver has a short circuit fault.

6. The method of claim 4, wherein the step of detecting the operating state of the relay includes the steps of: detecting the operating state of the relay by using the voltage across the relay. The working state detection result of the relay according to the third voltage and the fourth voltage comprises: when the first high-side voltage is consistent with the first voltage and the first low-side voltage is consistent with the first voltage, switching the working state of the high-side driver to a closed state; obtaining a second high-side voltage corresponding to the high-side driver and a second low-side voltage corresponding to the low-side driver; switching the working state of the low-side driver to a closed state when the second high-side voltage is consistent with the output voltage of the high-side driver and the second low-side voltage is consistent with the output voltage of the high-side driver; acquiring a third low-side voltage corresponding to the low-side driver and a second difference between the third low-side voltage and a preset voltage threshold; when the second difference is within a preset tolerance threshold range, acquiring an eighth voltage corresponding to the first end of the relay and a ninth voltage corresponding to the second end of the relay; when the eighth voltage is inconsistent with the ninth voltage, determining that the relay cannot be closed.

7. The method of claim 6, wherein the relay is a battery relay. The working state detection result of the relay according to the third voltage and the fourth voltage includes: when the second difference is not within the preset tolerance threshold range, counting a first number of times when the third low-side voltage is consistent with the output voltage of the high-side driver within a preset time length; when the first number of times reaches a preset number threshold, determining that the low-side driver has an open circuit fault.

8. The method of claim 6, wherein the relay is a battery relay. After the working state detection result of the relay according to the third voltage and the fourth voltage, including: when the second high-side voltage is inconsistent with the output voltage of the high-side driver or the second low-side voltage is inconsistent with the output voltage of the high-side driver, counting a second number of times when the second high-side voltage is consistent with the first voltage and a third number of times when the second low-side voltage is consistent with the first voltage within a preset time length; when the second number of times reaches a preset number threshold and the third number of times reaches a preset number threshold, determining that the high-side driver has an open circuit fault.

9. A battery system relay operating state detection circuit, wherein, including a first voltage applying module, a second voltage applying module, a first voltage measuring module, a second voltage measuring module, and a state detection module; The output end of the first voltage applying module is connected to the first end of the relay, and the input end of the first voltage applying module is connected to the output end of the state detection module, and the state detection module is used to control the first voltage applying module to apply a first voltage to the first end of the relay. The output end of the second voltage applying module is connected to the second end of the relay, and the input end of the second voltage applying module is connected to the output end of the state detection module, and the state detection module is also used to control the second voltage applying module to apply a second voltage to the second end of the relay. The output end of the state detection module is connected to the input end of the high-side driver connected in series to the first end of the relay, and is used to switch the working state of the high-side driver to an open state. The output end of the state detection module is connected to the input end of the low-side driver connected in series to the second end of the relay, and is used to switch the working state of the low-side driver to an open state. The input end of the first voltage measuring module is connected to the first end of the relay, and is used to acquire a third voltage corresponding to the first end. The input end of the second voltage measuring module is connected to the second end of the relay, and is used to acquire a fourth voltage corresponding to the second end. The output end of the first voltage measurement module is connected with the output end of the second voltage measurement module, and the input end of the state detection module, and the third voltage and the fourth voltage are sent to the state detection module, and the state detection module is used for obtaining the working state detection result of the relay according to the third voltage and the fourth voltage.

10. The operating state detection circuit for a relay of a battery system according to claim 9, wherein The high-side voltage measurement module and the low-side voltage measurement module are further included. The input end of the high-side voltage measurement module is connected with the first end of the relay, and the output end of the high-side voltage measurement module is connected with the input end of the state detection module, so as to obtain the high-side voltage corresponding to the high-side driver and send the high-side voltage to the state detection module. The input end of the low-side voltage measurement module is connected with the second end of the relay, and the output end of the low-side voltage measurement module is connected with the input end of the state detection module, so as to obtain the low-side voltage corresponding to the low-side driver and send the low-side voltage to the state detection module.

11. The operating state detection circuit for a relay of a battery system according to claim 9, wherein The fast discharge module and the slow discharge module are further included, the control end of the fast discharge module is connected with the state detection module, the output end of the fast discharge module is connected with the second end of the relay, the control end of the slow discharge module is connected with the state detection module, and the output end of the slow discharge module is connected with the second end of the relay. The fast discharge module is used for applying a fifth voltage to the second end of the relay according to a preset fast voltage application mode. The slow discharge module is used for applying the fifth voltage to the second end of the relay according to a preset slow voltage application mode.

12. The operating state detection circuit for a relay of a battery system according to claim 9, wherein The first diode and the second diode are further included. The anode of the first diode is connected with the output end of the first voltage application module, and the cathode of the first diode is connected with the first end of the relay. The anode of the second diode is connected with the output end of the second voltage application module, and the cathode of the second diode is connected with the second end of the relay.

13. The operating state detection circuit for a relay of a battery system according to claim 9, wherein The first voltage output by the first voltage application module is different from the second voltage output by the second voltage application module, and the first voltage and the second voltage are both less than the minimum coil actuation voltage of the relay.

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