Relay sticking detection circuit, device, and battery management system

Abstract

The application provides a relay sticking detection circuit, a device and a battery management system, and the relay sticking detection circuit comprises: a first collection end of a signal collection device is connected with a second end of a first relay, a second collection end receives a second power supply signal, and a first receiving end receives a first power supply signal; a control end of a processor is connected with the second receiving end of the signal collection device through a triode, and the processor is used for controlling the signal collection device to work through the triode; an analog-to-digital converter is connected with the second collection end of the signal collection device and the collection end of the processor, and is used for isolating a circuit, when the signal collection device is in a working state, the voltage on the second collection end of the signal collection device is collected, and the voltage is converted into a voltage signal, so that the voltage signal is transmitted to the collection end of the processor, so that the processor determines whether the first relay is stuck based on the voltage signal. In the above manner, the application can improve the efficiency and accuracy of relay sticking detection.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a relay sticking detection circuit, device, and battery management system. Background Technology

[0002] With the ongoing electrification process driven by energy conservation and intelligence, cleaner and more efficient new energy electric vehicles are poised to replace traditional gasoline-powered vehicles as the future trend. As electric vehicles continue to develop and improve, their operational safety is increasingly being emphasized, particularly the safety of the battery module. Currently, relay adhesion detection has become an essential safety detection function in Battery Management Systems (BMS), eliminating unsafe factors that may exist during the charging and discharging process of the battery module.

[0003] Currently, many battery management systems rely on the bus voltage collected from the high-voltage relay of the battery module to determine whether the relay is stuck. However, this method is easily affected by the charging and discharging rate of the large capacitor between the motor controller bus voltage and the bus voltage. Furthermore, the software detection logic is complex, resulting in low efficiency and poor accuracy in relay sticking detection. Summary of the Invention

[0004] In view of this, the present invention provides a relay adhesion detection circuit, device and battery management system that can improve the efficiency and accuracy of relay adhesion detection.

[0005] To address the aforementioned technical problems, this invention provides a relay adhesion detection circuit for detecting adhesion in a relay module. The relay module includes a first relay, with a first terminal connected to the negative terminal of a battery module and a second terminal connected to the positive terminal of the battery module via a load. The relay adhesion detection circuit includes: a signal acquisition device, with a first acquisition terminal connected to the second terminal of the first relay, a second acquisition terminal receiving a second power supply signal, and a first receiving terminal receiving a first power supply signal, wherein the power supply providing the first power supply signal is different from the power supply providing the second power supply signal; a processor, with its control terminal connected to the second receiving terminal of the signal acquisition device via a transistor, and the processor controlling the operation of the signal acquisition device via the transistor; and an analog-to-digital converter connected to the second acquisition terminal of the signal acquisition device and the acquisition terminal of the processor, serving as an isolation circuit. When the signal acquisition device is in operation, the converter acquires the voltage at the second acquisition terminal of the signal acquisition device and converts the voltage into a voltage signal, which is then transmitted to the acquisition terminal of the processor, allowing the processor to determine whether the first relay is adhered based on the voltage signal.

[0006] According to some embodiments of the present invention, the signal acquisition device includes: a first resistor, a second resistor, a third resistor, and a first diode; an optocoupler, wherein a first pin of the optocoupler serves as a first receiving terminal of the signal acquisition device, a second pin of the optocoupler serves as a second receiving terminal of the signal acquisition device, a third pin of the optocoupler serves as a first acquiring terminal of the signal acquisition device, and a fourth pin of the optocoupler serves as a second acquiring terminal of the signal acquisition device; wherein the first pin is used to receive a first power supply signal through the first resistor; the first pin is connected to the second pin through the third resistor, the third pin is connected to the second terminal of the first relay through the first diode, and the fourth pin receives a second power supply signal through the second resistor.

[0007] According to some embodiments of the present invention, the anode of the first diode is connected to the third pin of the optocoupler, and the cathode of the first diode is connected to the second terminal of the first relay, wherein the first diode is used to limit the voltage on the fourth pin of the optocoupler when the first relay is stuck.

[0008] According to some embodiments of the present invention, the processor is configured to determine that the first relay is not stuck when the voltage difference between the voltage signal and the first power supply signal is within a first preset difference range; and to determine that the first relay is stuck when the voltage difference between the voltage signal and the diode limiting voltage is within a second preset difference range.

[0009] According to some embodiments of the present invention, the collector of the transistor is connected to the second pin of the optocoupler and the other end of the third resistor, the emitter of the transistor is connected to the first ground terminal, and the base of the transistor is connected to the control pin of the processor.

[0010] According to some embodiments of the present invention, the relay adhesion detection circuit further includes: an analog-to-digital converter connected to the fourth pin of the optocoupler and the acquisition terminal of the processor, used to isolate the circuit, acquire the voltage on the fourth pin of the optocoupler and convert the voltage into a voltage signal, so as to transmit the voltage signal to the acquisition terminal of the processor.

[0011] According to some embodiments of the present invention, the relay module further includes a second relay, the first terminal of which is connected to the positive terminal of the battery module, and the second terminal of which is connected to the second terminal of the first relay through a load. The relay sticking detection circuit further includes: a first current limiting unit circuit, one end of which is connected to the second terminals of the second and third relays; a first operational amplifier, the non-inverting input terminal of which is connected to the other end of the first current limiting unit circuit, and the inverting input terminal of which is connected to the analog-to-digital converter; and a second current limiting unit circuit, one end of which is connected to the non-inverting input terminal of the first operational amplifier, and the other end of which is connected to the negative terminal of the battery module.

[0012] According to some embodiments of the present invention, the relay module further includes a third relay connected in parallel with the second relay. The first terminal of the third relay is connected to the positive terminal of the battery module, and the second terminal of the third relay is connected to the second terminal of the first relay through a load. The relay sticking detection circuit further includes: a third current limiting unit circuit, one end of which is connected to the positive terminal of the battery module; a second operational amplifier, the non-inverting input terminal of which is connected to the other end of the third current limiting unit circuit, and the inverting input terminal of which is connected to the analog-to-digital converter; and a fourth current limiting unit circuit, one end of which is connected to the non-inverting input terminal of the second operational amplifier, and the other end of which is connected to the negative terminal of the battery module. The processor is further configured to acquire the output voltages of the first and second operational amplifiers via the analog-to-digital converter, and determine whether the second and third relays are stuck based on the output voltages of the first and second operational amplifiers.

[0013] According to some embodiments of the present invention, the processor is configured to determine that at least one of the second relay and the third relay is stuck when the output voltage of the first operational amplifier is not zero and the difference between the output voltage of the first operational amplifier and the output voltage of the second operational amplifier is within a third preset difference range.

[0014] According to some embodiments of the present invention, the relay adhesion detection circuit further includes: a first voltage regulator unit circuit, one end of which is connected to the other end of a first current limiting unit circuit, and the other end of which is connected to the negative terminal of the battery module; and a second voltage regulator unit circuit, one end of which is connected to the other end of a third current limiting unit circuit, and the other end of which is connected to the negative terminal of the battery module.

[0015] Secondly, embodiments of the present invention provide a relay adhesion detection device, including a relay adhesion detection circuit, wherein the relay adhesion detection circuit is the relay adhesion detection circuit in the above embodiments.

[0016] Thirdly, embodiments of the present invention provide a battery management system, including: a relay module and a relay adhesion detection device, wherein the relay module includes a first relay, a first end of the first relay is used to connect to the negative terminal of the battery module, and a second end of the first relay is used to connect to the positive terminal of the battery module through a load; the relay adhesion detection device is the relay adhesion detection device in the above embodiments, used to detect adhesion of the relay module.

[0017] The above-mentioned technical solution of the present invention has at least one of the following beneficial effects: the relay adhesion detection circuit has a simple structure and is easy to implement, avoiding the use of the bus voltage collected from the high-voltage relay of the battery module as the basis for judging whether the relay is stuck, and can achieve efficient and high-precision adhesion detection. Furthermore, it is applicable to relay control and its application in engineering circuits in the field of new energy electric vehicles, providing a fundamental guarantee for the safety of electric vehicles and playing a significant role in promoting the development of new energy electric vehicle circuit systems.

[0018] Furthermore, the relay adhesion detection circuit eliminates the need for inductive components, effectively avoiding the impact of the parasitic equivalent series resistance inside the inductive components on the detection accuracy, thus further ensuring the adhesion detection accuracy.

[0019] Furthermore, the setting of the first preset difference range and the second preset difference range can avoid errors and prevent voltage fluctuations on the fourth pin of the optocoupler IC due to the influence of other components in the circuit, thereby improving the accuracy of adhesion detection using voltage values.

[0020] Furthermore, by acquiring the output voltage of each operational amplifier and the pin voltage of the optocoupler, the sticking detection of each relay in the high-voltage circuit can be realized, making the sticking detection more efficient and comprehensive.

[0021] Furthermore, by setting a third preset difference threshold, the error between the pre-charge voltage and the battery module voltage can be avoided, thereby further improving the detection accuracy. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a battery management system according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of a relay adhesion detection device according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of a relay adhesion detection circuit according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of a relay adhesion detection circuit according to another embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of a relay adhesion detection circuit according to another embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of a relay adhesion detection circuit according to another embodiment of the present invention;

[0028] Figure 7This is a schematic diagram of a relay adhesion detection circuit according to another embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of a relay adhesion detection circuit according to another embodiment of the present invention. Detailed Implementation

[0030] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] like Figure 1 As shown, the battery management system 1000 of this embodiment includes a relay module 1001 and a relay adhesion detection device 1002. The relay module 1001 includes a first relay, a first terminal of which is connected to the negative terminal of the battery module, and a second terminal of which is connected to the positive terminal of the battery module through a load. The relay adhesion detection device 1002 is the relay adhesion detection device in the following embodiment, which is used to detect adhesion of the relay module 1001.

[0032] In one embodiment, the battery management system 1000 can be applied to new energy electric vehicles, the first relay can be a high-voltage relay on the high-voltage circuit of the new energy electric vehicle, and the load can be a motor. In other embodiments, the battery management system 1000 can also be applied to other scenarios, which are not limited here.

[0033] like Figure 2 As shown, the relay adhesion detection device 2000 of this embodiment includes a relay adhesion detection circuit 2001, wherein the relay adhesion detection circuit 2001 is the relay adhesion detection circuit in the following embodiments, which will not be described in detail here.

[0034] The relay adhesion detection device 2000 can improve the efficiency and accuracy of relay adhesion detection through the relay adhesion detection circuit 2001. The relay adhesion detection circuit 2001 will be described in detail below.

[0035] like Figure 3 As shown in the figure, the relay adhesion detection circuit of this invention is used to detect adhesion of relay modules in a battery management system. The relay module includes a first relay S1, which can be the main negative relay on the high-voltage circuit, i.e., a B-relay. The first terminal of the first relay S1 is used to connect to the negative terminal Bat- of the battery module, and the second terminal of the first relay S1 is used to connect to the positive terminal Bat+ of the battery module through a load. The relay adhesion detection circuit may include a signal acquisition device, a transistor Q1, an analog-to-digital converter, and a processor.

[0036] The third capacitor C3 is the high-voltage capacitor at the load end. The processor can receive the first power supply signal VCC1 and connect it to the first ground terminal GND1; the analog-to-digital converter can receive the second power supply signal VCC2 and connect it to the second ground terminal GND2. The power supply providing the first power supply signal VCC1 is different from the power supply providing the second power supply signal VCC2. The processor can be a microcontroller unit (MCU) or other processing chip, which is not limited here.

[0037] The first acquisition terminal of the signal acquisition device is connected to the second terminal of the first relay S1. The second acquisition terminal receives the second power supply signal VCC2, and the first receiving terminal receives the first power supply signal VCC1.

[0038] The analog-to-digital converter is connected to the second acquisition terminal of the signal acquisition device and the acquisition terminal of the processor. It is used to isolate the circuit. When the signal acquisition device is in working state, it acquires the voltage on the second acquisition terminal of the signal acquisition device and converts the voltage into a voltage signal, so as to transmit the voltage signal to the acquisition terminal of the processor, thereby enabling the processor to determine whether the first relay is stuck based on the voltage signal.

[0039] The relay sticking detection circuit in this embodiment has a simple structure and is easy to implement. It avoids using the bus voltage collected from the high-voltage relay of the battery module as the basis for judging whether the relay is sticking, and can achieve efficient and high-precision sticking detection. In addition, it is applicable to relay control and its application in engineering circuits in the field of new energy electric vehicles, providing a fundamental guarantee for the safety of electric vehicles and playing a significant role in promoting the development of new energy electric vehicle circuit systems.

[0040] In one embodiment, such as Figure 4 As shown, the signal acquisition device may include: an optocoupler IC, a first resistor R1, a first diode D1, a second resistor R2, and a third resistor R3, wherein the first pin of the optocoupler IC serves as the first receiving end of the signal acquisition device, the second pin of the optocoupler IC serves as the second receiving end of the signal acquisition device, the third pin of the optocoupler IC serves as the first acquisition end of the signal acquisition device, and the fourth pin of the optocoupler IC serves as the second acquisition end of the signal acquisition device.

[0041] The first pin of the optocoupler IC receives the first power supply signal VCC1 through the first resistor R1. The first pin is connected to the second pin of the optocoupler IC through the third resistor R3. The third pin is connected to the second terminal of the first relay S1 through the first diode D1. The fourth pin receives the second power supply signal VCC2 through the second resistor R2. The processor's control terminal is connected to the second pin of the optocoupler IC through the transistor Q1. The processor controls the operation of the optocoupler IC through the transistor Q1.

[0042] In one embodiment, the collector of transistor Q1 is connected to the second pin of optocoupler IC and the other end of third resistor R3, the emitter of transistor Q1 is connected to the first ground terminal GND1, and the base of transistor Q1 is connected to the control pin of processor.

[0043] In one embodiment, the anode of the first diode D1 is connected to the third pin of the optocoupler IC, and the cathode of the first diode D1 is connected to the second terminal of the first relay S1. The first diode D1 is used to limit the voltage on the fourth pin of the optocoupler IC when the first relay S1 is stuck. Specifically, when the first relay S1 is stuck, the third pin of the optocoupler IC is connected to the negative terminal Bat- of the battery module, and the voltage on the fourth pin of the optocoupler IC can be clamped to approximately 0.7V by the first diode D1.

[0044] In one embodiment, one, two, or more second diodes D2 (not shown in the figure) may be connected in series with the first diode D1 to improve the diode's withstand voltage capability. The anode of the first diode D1 can be connected to the third pin of the optocoupler IC, the anode of the second diode D2 is connected to the cathode of the first diode D1, and the cathode of the second diode D2 is connected to the second terminal of the first relay S1. Understandably, the number of second diodes D2 can be selected according to actual needs and is not limited here.

[0045] In one embodiment, the processor can be used to determine that the first relay S1 is not stuck when the voltage difference between the voltage signal and the first power supply signal VCC1 is within a first preset difference range; and to determine that the first relay S1 is stuck when the voltage difference between the voltage signal and the diode limiting voltage is within a second preset difference range.

[0046] When the optocoupler IC is in operation, the first relay S1 is open, and the third pin of the optocoupler IC is floating. At this time, the voltage on the fourth pin of the optocoupler IC is pulled up to the voltage of the first power supply signal VCC1, for example, 5V. Therefore, when the voltage difference between the voltage signal and the first power supply signal VCC1 is within a first preset difference range, it can be determined that the first relay S1 is not stuck. When the first relay S1 is stuck, the third pin of the optocoupler IC is connected to the negative terminal Bat- of the battery module, and the voltage on the fourth pin of the optocoupler IC is clamped to about 0.7V by the diode. This 0.7V is the diode limiting voltage. Understandably, the diode limiting voltage is related to the number of diodes and hardware conditions, and is not limited here.

[0047] By setting the first and second preset difference ranges, errors can be avoided, preventing detection errors caused by voltage fluctuations on the fourth pin of the optocoupler IC due to the influence of other components in the circuit. This improves the accuracy of adhesion detection using voltage values. Understandably, the values ​​of the first and second preset difference ranges can be set according to actual conditions; for example, a larger range can be set when the error is large, and a smaller range can be set when the error is small. No limitation is made here.

[0048] The relay adhesion detection circuit in this embodiment has a simple structure and is easy to implement, enabling efficient and high-precision adhesion detection. Furthermore, the use of a differential range helps to mitigate errors and avoid voltage fluctuations on the fourth pin of the optocoupler caused by the influence of other components in the circuit, thereby improving the accuracy of adhesion detection using voltage values. In addition, the relay adhesion detection circuit eliminates the need for inductive components, effectively avoiding the impact of the parasitic equivalent series resistance inside inductive components on detection accuracy, further ensuring the accuracy of adhesion detection.

[0049] In one embodiment, such as Figure 5 As shown, the relay module may also include a second relay S2, wherein the second relay S2 may be the main positive relay on the high voltage circuit, i.e., the B+ relay. The first terminal of the second relay S2 is connected to the positive terminal Bat+ of the battery module, and the second terminal of the second relay S2 is connected to the second terminal of the first relay S1 through the load. The relay sticking detection circuit may also include a first current limiting unit circuit, a first operational amplifier OPA1, and a second current limiting unit circuit.

[0050] Specifically, one end of the first current limiting unit circuit is connected to the second end of the second relay S2. The non-inverting input of the first operational amplifier OPA1 is connected to the other end of the first current limiting unit circuit, and the inverting input of the first operational amplifier OPA1 is connected to the analog-to-digital converter. One end of the second current limiting unit circuit is connected to the non-inverting input of the first operational amplifier OPA1, and the other end of the second current limiting unit circuit is connected to the negative terminal Bat- of the battery module.

[0051] In one embodiment, such as Figure 6As shown, the relay module may also include a third relay S3 connected in parallel with the second relay S2. The third relay S3 can be a pre-charge relay in the high-voltage circuit, and the twelfth resistor R12 connected in series with the third relay S3 is the pre-charge resistor, serving as a buffer for power-on. The first terminal of the third relay S3 is connected to the positive terminal Bat+ of the battery module, and the second terminal of the third relay S3 is connected to the second terminal of the first relay S1 through a load. The relay sticking detection circuit may also include a third current-limiting unit circuit, a second operational amplifier OPA2, and a fourth current-limiting unit circuit. The processor is also used to acquire the output voltages of the first operational amplifier OPA1 and the second operational amplifier OPA2 through an analog-to-digital converter, and determine whether the second relay S2 and the third relay S3 are stuck based on the output voltages of the first operational amplifier OPA1 and the second operational amplifier OPA2.

[0052] Specifically, one end of the third current limiting unit circuit is connected to the positive terminal Bat+ of the battery module. The non-inverting input of the second operational amplifier OPA2 is connected to the other end of the third current limiting unit circuit, and the inverting input of the second operational amplifier OPA2 is connected to the analog-to-digital converter. One end of the fourth current limiting unit circuit is connected to the non-inverting input of the second operational amplifier OPA2, and the other end of the fourth current limiting unit circuit is connected to the negative terminal Bat- of the battery module.

[0053] In one embodiment, such as Figure 7 As shown, the first current-limiting unit circuit may include a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6 connected in series. The second current-limiting unit circuit may include a seventh resistor R7. The third current-limiting unit circuit may include an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10 connected in series. The fourth current-limiting unit circuit may include an eleventh resistor R11. The specifications of the first and third current-limiting unit circuits are identical, and the specifications of the third and fourth current-limiting unit circuits are identical, meaning the resistance values ​​are identical. It is understood that in other embodiments, the first, second, third, and fourth current-limiting unit circuits may employ other circuit structures capable of achieving current-limiting effects, which are not limited here.

[0054] In one embodiment, the processor can determine that at least one of the second relay S2 and the third relay S3 is stuck when the output voltage of the first operational amplifier OPA1 is not zero and the difference between the output voltage of the first operational amplifier OPA1 and the output voltage of the second operational amplifier OPA2 is within a third preset difference range.

[0055] Depend on Figure 7 It can be seen that the output voltage of the first operational amplifier OPA1 can be expressed as shown in the following formula (1):

[0056]

[0057] Where U' is the precharge voltage and V1 is the output voltage of the first operational amplifier OPA1.

[0058] The output voltage of the second operational amplifier OPA2 can be expressed as shown in the following formula (2):

[0059]

[0060] Where U is the voltage of the battery module, and V2 is the output voltage of the second operational amplifier OPA2.

[0061] When both the second relay S2 and the third relay S3 are disconnected, the precharge voltage is close to 0. When either the second relay S2 or the third relay S3 is connected, the precharge voltage is close to the voltage of the battery module. Assuming the voltage U of the battery module is 380V, R7 is 10K, and R4, R5, and R6 are 499K respectively, correspondingly, R11 is 10K, and R8, R9, and R10 are 499K respectively, then when either the second relay S2 or the third relay S3 is connected, theoretically, according to the above formulas (1)-(2), the output voltage of the second operational amplifier OPA2 and the output voltage of the first operational amplifier OPA1 are both approximately 2.53V.

[0062] However, in practical applications, if either the second relay S2 or the third relay S3 becomes stuck, differences in the length and impedance of the high-voltage circuit copper busbar and the relay model may cause a certain error between the pre-charge voltage and the battery module voltage. Therefore, by setting a third preset difference threshold, when the difference between the output voltages of the first operational amplifier OPA1 and the second operational amplifier OPA2 falls within the third preset difference range, it is determined that at least one of the second relay S2 and the third relay S3 is stuck, thereby avoiding errors and improving the accuracy of sticking detection. Understandably, the value of the third preset difference range can be set according to actual conditions and is not limited here.

[0063] In one embodiment, the processor is also configured to determine that the battery module has an internal pressure abnormality when the output voltage of the second operational amplifier OPA2 is zero.

[0064] In one embodiment, the relay adhesion detection circuit may further include a first voltage regulator unit circuit and a second voltage regulator unit circuit. One end of the first voltage regulator unit circuit is connected to the other end of the first current limiting unit circuit, and the other end of the first voltage regulator unit circuit is connected to the negative terminal Bat- of the battery module. One end of the second voltage regulator unit circuit is connected to the other end of the third current limiting unit circuit, and the other end of the second voltage regulator unit circuit is connected to the negative terminal Bat- of the battery module. Figure 8 As shown, the first voltage regulator circuit may include a first capacitor C1, and the second voltage regulator circuit may include a second capacitor C2.

[0065] This embodiment achieves sticking detection of each relay in the high-voltage circuit by acquiring the output voltage of each operational amplifier and the pin voltage of the optocoupler, making the sticking detection more efficient and comprehensive. Furthermore, by setting a third preset difference threshold, the error between the pre-charge voltage and the battery module voltage can be avoided, further improving the detection accuracy. In addition, it is applicable to relay control in the field of new energy electric vehicles and its application in engineering circuits, providing fundamental protection for the safety of electric vehicles and playing a significant role in promoting the development of new energy electric vehicle circuit systems.

[0066] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A relay adhesion detection circuit, characterized in that, For detecting adhesion in a relay module, wherein the relay module includes a first relay, a first terminal of the first relay is used to connect to the negative terminal of the battery module, and a second terminal of the first relay is used to connect to the positive terminal of the battery module through a load; the relay adhesion detection circuit includes: A signal acquisition device, wherein a first acquisition end of the signal acquisition device is connected to a second end of the first relay, the second acquisition end receives a second power supply signal, and the first receiving end receives a first power supply signal, wherein the power supply providing the first power supply signal is different from the power supply providing the second power supply signal; The processor has its control terminal connected to the second receiving terminal of the signal acquisition device via a transistor, and the processor is used to control the operation of the signal acquisition device through the transistor. An analog-to-digital converter is connected to the second acquisition terminal of the signal acquisition device and the acquisition terminal of the processor. It is used to isolate the circuit. When the signal acquisition device is in working state, it acquires the voltage on the second acquisition terminal of the signal acquisition device and converts the voltage into the voltage signal, so as to transmit the voltage signal to the acquisition terminal of the processor, thereby enabling the processor to determine whether the first relay is stuck based on the voltage signal. The signal acquisition device includes: First resistor, second resistor, third resistor, and first diode; An optocoupler is provided, wherein a first pin of the optocoupler serves as a first receiving terminal of the signal acquisition device, a second pin of the optocoupler serves as a second receiving terminal of the signal acquisition device, a third pin of the optocoupler serves as a first acquiring terminal of the signal acquisition device, and a fourth pin of the optocoupler serves as a second acquiring terminal of the signal acquisition device; wherein the first pin is used to receive the first power supply signal through the first resistor; the first pin is connected to the second pin through the third resistor, the third pin is connected to the second terminal of the first relay through the first diode, and the fourth pin receives the second power supply signal through the second resistor; The anode of the first diode is connected to the third pin of the optocoupler, and the cathode of the first diode is connected to the second terminal of the first relay, wherein the first diode is used to limit the voltage on the fourth pin of the optocoupler when the first relay is stuck.

2. The relay adhesion detection circuit according to claim 1, characterized in that, The processor is used to determine that the first relay is not stuck when the voltage difference between the voltage signal and the first power supply signal is within a first preset difference range; When the voltage difference between the voltage signal and the diode limiting voltage is within a second preset difference range, it is determined that the first relay is stuck.

3. The relay adhesion detection circuit according to claim 1, characterized in that, The collector of the transistor is connected to the second pin of the optocoupler and the other end of the third resistor, the emitter of the transistor is connected to the first ground terminal, and the base of the transistor is connected to the control pin of the processor.

4. The relay adhesion detection circuit according to claim 1, characterized in that, The relay module further includes a second relay, the first terminal of which is connected to the positive terminal of the battery module, and the second terminal of which is connected to the second terminal of the first relay through the load. The relay adhesion detection circuit further includes: A first current limiting unit circuit, one end of which is connected to the second end of the second relay; The first operational amplifier has its non-inverting input connected to the other end of the first current limiting unit circuit, and its inverting input connected to the analog-to-digital converter. The second current limiting unit circuit has one end connected to the non-inverting input of the first operational amplifier, and the other end connected to the negative terminal of the battery module.

5. The relay adhesion detection circuit according to claim 4, characterized in that, The relay module further includes a third relay connected in parallel with the second relay. The first terminal of the third relay is connected to the positive terminal of the battery module, and the second terminal of the third relay is connected to the second terminal of the first relay via the load. The relay adhesion detection circuit further includes: The third current limiting unit circuit, one end of which is connected to the positive terminal of the battery module; The second operational amplifier has its non-inverting input connected to the other end of the third current limiting unit circuit, and its inverting input connected to the analog-to-digital converter. The fourth current limiting unit circuit has one end connected to the non-inverting input terminal of the second operational amplifier, and the other end connected to the negative terminal of the battery module. The processor is further configured to acquire the output voltages of the first operational amplifier and the second operational amplifier through the analog-to-digital converter, and determine whether the second relay and the third relay are stuck together based on the output voltages of the first operational amplifier and the second operational amplifier.

6. The relay adhesion detection circuit according to claim 5, characterized in that, The processor is configured to determine that at least one of the second relay and the third relay is stuck when the output voltage of the first operational amplifier is not zero and the difference between the output voltage of the first operational amplifier and the output voltage of the second operational amplifier is within a third preset difference range.

7. The relay adhesion detection circuit according to claim 5, characterized in that, The relay adhesion detection circuit also includes: A first voltage regulator unit circuit, one end of which is connected to the other end of the first current limiting unit circuit, and the other end of which is connected to the negative terminal of the battery module. The second voltage regulator circuit has one end connected to the other end of the third current limiting circuit, and the other end connected to the negative terminal of the battery module.

8. A relay adhesion detection device, characterized in that, The invention includes a relay adhesion detection circuit, wherein the relay adhesion detection circuit is the relay adhesion detection circuit according to any one of claims 1-7.

9. A battery management system, characterized in that, include: A relay module, the relay module including a first relay, a first terminal of the first relay being used to connect to the negative terminal of the battery module, and a second terminal of the first relay being used to connect to the positive terminal of the battery module through a load; The relay adhesion detection device is the relay adhesion detection device described in claim 8 above, used to perform adhesion detection on the relay module.

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