Dry contact control circuit and battery management system

Abstract

The utility model discloses a dry contact control circuit and a battery management system, and relates to the technical field of dry contact control, and the circuit comprises a signal processing circuit which is used for receiving a pulse signal output when a main controller works normally and then forwarding the pulse signal, and the signal processing circuit is also used for filtering a level signal output when the main controller fails; the dry contact driving circuit is used for generating a dry contact driving signal and outputting the dry contact driving signal when the forwarded pulse signal is received; the dry contact working circuit is used for controlling the power supply end of the battery management system to supply power to the coil according to the received driving signal so as to control the relay to conduct the dry contact. Thus, pulse signals output by the main controller can be received through the signal processing circuit, and level signals output when the main controller breaks down are filtered, so that the dry contact driving circuit is controlled to drive the relay to conduct the dry contact, the dry contact can be prevented from being in a conducting state all the time, and when the controller is abnormal, the dry contact is disconnected immediately.

Description

Technical Field

[0001] The utility model relates to the technical field of dry contact control, in particular to a dry contact control circuit and a battery management system. Background Art

[0002] As an electrical switch, dry contacts have two states: closed and open. There are no polarity requirements between the two contacts of a dry contact and they are interchangeable. Compared to wet contacts, dry contacts offer advantages such as ease of access, reduced engineering difficulty, increased engineering speed, ease of access, standardized interfaces, and device-friendliness. Therefore, dry contact signals are widely used in industrial control.

[0003] However, existing dry contact control circuits often cause the main controller's output signal level to become uncontrolled due to program errors or unexpected main controller freezes. If the signal level remains high, the dry contact remains closed and cannot be disconnected. Even in the event of an abnormality such as a battery short circuit, the monitoring system will still believe that everything is normal because the dry contact cannot be disconnected. This makes it impossible to inspect and repair the battery, and the battery management system cannot control the battery to properly power communication equipment during a mains power outage, which can even cause the communication base station to stop working. Utility Model Content

[0004] The main purpose of the utility model is to propose a dry contact control circuit and a battery management system, which aims to solve the problem that the signal level output by the main controller is uncontrolled due to a fault, causing the dry contact to be always closed and unable to be disconnected.

[0005] To achieve the above-mentioned purpose, the dry contact control circuit proposed in the present invention is applied to a battery management system. The battery management system is provided with a main controller. The circuit includes:

[0006] a signal processing circuit, wherein the signal input end of the signal processing circuit is electrically connected to the pulse signal output end of the main controller, and the power input end of the signal processing circuit is electrically connected to the first power supply end of the battery management system, and is used to receive and forward the pulse signal output by the main controller when the main controller is operating normally, and the signal processing circuit is further used to filter the level signal output by the main controller when it fails;

[0007] a dry contact driving circuit, wherein a signal input terminal of the dry contact driving circuit is electrically connected to a signal output terminal of the signal processing module, and is configured to generate and output a dry contact driving signal upon receiving the forwarded pulse signal;

[0008] A dry contact working circuit, wherein the controlled end of the dry contact working circuit is electrically connected to the signal output end of the dry contact drive circuit, the dry contact working circuit is used to connect to the coil of the relay and the second power supply end of the battery management system, and the dry contact working circuit is used to control the power supply end of the battery management system to power the coil according to the received drive signal, so as to control the relay to turn on the dry contact.

[0009] In one embodiment, the signal processing circuit includes a signal inversion circuit and a signal filtering circuit;

[0010] a signal inversion circuit, wherein the signal input end of the signal inversion circuit is electrically connected to the pulse signal output end of the main controller, and the power input end of the signal inversion circuit is electrically connected to the first power supply end of the battery management system, and is used to forward the pulse signal output by the main controller when it is working normally;

[0011] A signal filtering circuit, wherein the signal input end of the signal filtering circuit is electrically connected to the signal output end of the signal flipping circuit, and the signal output end of the signal filtering circuit is electrically connected to the signal input end of the dry contact driving circuit, and is used to filter the level signal output when the main controller fails.

[0012] In one embodiment, the signal inversion circuit includes a first resistor, a second resistor, a third resistor, and a first transistor;

[0013] The pulse signal output end of the main controller is electrically connected to the first end of the first resistor and the first end of the second resistor, the second end of the second resistor is electrically connected to the first power supply end of the battery management system and the first end of the third resistor respectively, the second end of the third resistor is electrically connected to the signal input end of the signal filtering circuit and the collector of the first transistor, the base of the first transistor is electrically connected to the second end of the first resistor, and the emitter of the first transistor is grounded.

[0014] In one embodiment, the signal filtering circuit includes a first capacitor, a first end of the first capacitor is electrically connected to the signal output end of the signal inversion circuit, and a second end of the first capacitor is electrically connected to the signal input end of the dry contact driving circuit.

[0015] In one embodiment, the dry contact driving circuit includes a fourth resistor, a fifth resistor, and a second capacitor;

[0016] The first end of the fourth resistor, the first end of the fifth resistor and the first end of the second capacitor are respectively electrically connected to the signal output end of the signal processing module, the second end of the fifth resistor is electrically connected to the controlled end of the dry contact working circuit, and the second end of the fourth resistor and the second end of the fifth resistor are grounded.

[0017] In one embodiment, the dry contact working circuit includes a second transistor and a third capacitor;

[0018] The base of the second transistor is electrically connected to the signal output end of the dry contact drive circuit, the collector of the second transistor is electrically connected to the second power supply end of the battery management system and the first end of the coil, respectively, the first end of the third capacitor is electrically connected to the second end of the coil, and the emitter of the second transistor and the second end of the third capacitor are grounded.

[0019] In one embodiment, the circuit further comprises:

[0020] The anti-backflow circuit is provided on the line between the output end of the signal processing module and the dry contact driving circuit, and is used to prevent the dry contact driving circuit from outputting reverse current.

[0021] In one embodiment, the anti-backflow circuit includes a dual Schottky diode, a first end of the dual Schottky diode is electrically connected to the signal output end of the signal processing circuit, a second end of the dual Schottky diode is electrically connected to the input end of the dry contact drive circuit, and a third end of the dual Schottky diode is grounded.

[0022] In one embodiment, the circuit further comprises:

[0023] A freewheeling circuit is provided on a circuit between the second power supply end of the battery management system and the dry contact working circuit, and is used to release the residual voltage of the dry contact working circuit when the second power supply end of the battery management system stops supplying power.

[0024] The present utility model also provides a battery management system, which includes the dry contact control circuit as described above.

[0025] The technical solution of the present utility model adopts a dry contact control circuit, which is applied to a battery management system. The battery management system is provided with a main controller. The circuit includes: a signal processing circuit, wherein a signal input end of the signal processing circuit is electrically connected to a pulse signal output end of the main controller, and a power input end of the signal processing circuit is electrically connected to a first power supply end of the battery management system. The circuit is configured to receive and forward a pulse signal output by the main controller during normal operation. The signal processing circuit is further configured to filter a level signal output when the main controller fails; a dry contact drive circuit, wherein a signal input end of the dry contact drive circuit is electrically connected to a signal output end of the signal processing module. The circuit is configured to generate and output a dry contact drive signal upon receiving a forwarded pulse signal; and a dry contact working circuit, wherein a controlled end of the dry contact working circuit is electrically connected to the signal output end of the dry contact drive circuit. The dry contact working circuit is configured to be connected to a coil of a relay and a second power supply end of the battery management system. The dry contact working circuit is configured to control the power supply end of the battery management system to supply power to the coil according to the received drive signal, thereby controlling the relay to turn on the dry contact. In this way, the dry contact control circuit can receive the pulse signal output by the main controller when it is working normally through the signal processing circuit and forward it, and filter the level signal output when the main controller fails, so as to control the dry contact drive circuit to drive the relay to turn on the dry contact, so that the dry contact control circuit can prevent the dry contact from being in the on state all the time, so that when the controller has an abnormality, the dry contact will be disconnected immediately. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 This is a circuit system block diagram of an embodiment of a dry contact control circuit provided by the present invention;

[0028] Figure 2 This is a specific circuit structure diagram of an embodiment of the dry contact control circuit provided by the present utility model.

[0029] Description of Figure Numbers:

[0030] 1-Signal processing circuit; 11-Signal inversion circuit; 12-Signal filtering circuit; 2-Dry contact drive circuit; 3-Dry contact working circuit; 4-Anti-backflow circuit; 5-Freewheeling circuit.

[0031] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0033] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] In the communication base station power supply system, the battery in the battery management system serves as a backup power source. After the mains power is interrupted, it supplies power to the communication equipment to ensure the normal operation of the communication base station. The dry contact is an important function for the communication between the BMS (battery management system) and external equipment. It is used to inform the monitoring system whether the status of the internal battery is normal. The reliability of the dry contact of the battery management system plays an important role in the normal operation of the communication base station power supply system.

[0036] However, the dry contacts of BMS nowadays often adopt single-level control. It is easy for the main controller to output a single level continuously when it fails, causing the dry contacts to be turned on. When the battery management system fails, it mistakenly detects that the dry contacts are still connected. The battery cannot be inspected and repaired in time, and ultimately the battery cannot normally power the communication equipment when the mains power is interrupted, causing the communication base station to stop working.

[0037] Therefore, in this solution, the dry contact control circuit is used to receive pulse signals that can control the conduction of the dry contact, and filter the level signals emitted when the main controller fails, so as to increase the reliability of the dry contact in detecting the battery status.

[0038] Please refer to Figure 1 and Figure 2 The present invention proposes a dry contact control circuit, which is applied to a battery management system. The battery management system is provided with a main controller. The circuit includes:

[0039] A signal processing circuit 1, wherein the signal input terminal of the signal processing circuit 1 is electrically connected to the pulse signal output terminal of the main controller, and the power input terminal of the signal processing circuit 1 is electrically connected to the first power supply terminal of the battery management system. The signal processing circuit 1 is used to receive and forward the pulse signal output by the main controller when the main controller is operating normally. The signal processing circuit 1 is also used to filter the level signal output by the main controller when it fails;

[0040] A dry contact driving circuit 2, wherein the signal input terminal of the dry contact driving circuit 2 is electrically connected to the signal output terminal of the signal processing module, and is configured to generate and output a dry contact driving signal upon receiving the forwarded pulse signal;

[0041] The dry contact working circuit 3 has a controlled end electrically connected to the signal output end of the dry contact driving circuit 2. The dry contact working circuit 3 is used to connect to the coil of the relay K1 and the second power supply end of the battery management system. The dry contact working circuit 3 is used to control the power supply end of the battery management system to power the coil according to the received driving signal, so as to control the relay K1 to turn on the dry contact.

[0042] In this embodiment, the signal processing circuit 1 can be implemented using a filter circuit. The signal processing circuit 1 includes a signal inversion circuit 11 and a signal filtering circuit 12, wherein the signal input end of the signal inversion circuit 11 is electrically connected to the pulse signal output end of the main controller, and the power input end of the signal inversion circuit 11 is electrically connected to the first power supply end of the battery management system, which is used to forward the pulse signal output when the main controller is working normally. The signal input end of the signal filtering circuit 12 is electrically connected to the signal output end of the signal inversion circuit 11, and the signal output end of the signal filtering circuit 12 is electrically connected to the signal input end of the dry contact drive circuit 2, which is used to filter the level signal output when the main controller fails.

[0043] In this embodiment, the signal flipping circuit 11 includes a first resistor R1, a second resistor R2, a third resistor R3 and a first transistor Q1; the pulse signal output end of the main controller is electrically connected to the first end of the first resistor R1 and the first end of the second resistor R2, the second end of the second resistor R2 is electrically connected to the first power supply end of the battery management system and the first end of the third resistor R3, respectively, the second end of the third resistor R3 is electrically connected to the signal input end of the signal filtering circuit 12 and the collector of the first transistor Q1, the base of the first transistor Q1 is electrically connected to the second end of the first resistor R1, and the emitter of the first transistor Q1 is grounded. In this way, since the pulse signal output end of the main controller is set on the line connecting the first end of the first resistor R1 and the first end of the second resistor R2, the line is called point 1, and the line between the second end of the third resistor R3 and the collector of the first transistor Q1 is called point 2. When point 1 is output as a high level through the pulse signal, the high level is output to the base of the first transistor Q1 through the first resistor R1, driving the first transistor Q1 to turn on. At this time, the first transistor Q1 is grounded, causing point 2 to be a low level; if when point 1 is output as a low level through the pulse signal, since the first transistor Q1 is cut off, a loop is formed between the second resistor R2 and the third resistor R3, and the first power supply end of the battery management system supplies power to the loop at this time. The third resistor R3 is a pull-up resistor, which causes point 2 to be a high level at this time. Therefore, in the signal inversion circuit 11, the pulse signal output by the main controller can be simulated and forwarded to the signal filtering circuit 12.

[0044] In this embodiment, the signal filtering circuit 12 includes a first capacitor C1. The first end of the first capacitor C1 is electrically connected to the signal output end of the signal inversion circuit 11, and the second end of the first capacitor C1 is electrically connected to the signal input end of the dry contact driving circuit 2. In this way, due to the characteristic of capacitors that pass AC but block DC, the level signal output by the main controller when it fails can be filtered. Moreover, because the pulse signal, although not AC in the traditional sense, can still pass through the first capacitor C1 and be output to the dry contact driving circuit 2, the dry contact control circuit can both pass the pulse voltage output by the main controller when it is operating normally and filter the level signal output by the main controller when it fails, thereby improving the reliability of the dry contact operation.

[0045] In this embodiment, the dry contact driving circuit 2 includes a fourth resistor R4, a fifth resistor R5, and a second capacitor C2; the first end of the fourth resistor R4, the first end of the fifth resistor R5, and the first end of the second capacitor C2 are respectively electrically connected to the signal output end of the signal processing module, the second end of the fifth resistor R5 is electrically connected to the controlled end of the dry contact working circuit 3, and the second end of the fourth resistor R4 and the second end of the fifth resistor R5 are grounded. In this way, the fourth resistor R4 and the second capacitor C2 serve as an energy storage unit. When a pulse signal is output to the dry contact driving circuit 2, the second capacitor C2 can be continuously charged by means of the fourth resistor R4 until the voltage that the second capacitor C2 can accommodate reaches an upper limit. The voltage accommodated by the second capacitor C2 can be output to the controlled end of the dry contact working circuit 3 after passing through the fifth resistor R5. The output voltage is the dry contact driving signal, which enables the dry contact to be driven on or off using simple and low-cost components.

[0046] In this embodiment, the dry contact working circuit 3 includes a second transistor Q2 and a third capacitor; the base of the second transistor Q2 is electrically connected to the signal output end of the dry contact driving circuit 2, the collector of the second transistor Q2 is electrically connected to the second power supply end of the battery management system and the first end of the coil, respectively, the first end of the third capacitor is electrically connected to the second end of the coil, and the emitter of the second transistor Q2 and the second end of the third capacitor are grounded. In this way, the base of the second transistor Q2 is the controlled end of the dry contact working circuit 3. When the dry contact drive signal is output to the base of the second transistor Q2, the second transistor Q2 is turned on, and a loop is formed between the coil, the second transistor Q2 and the third capacitor. The second power supply end of the battery management system supplies power to the formed loop to control the current in the coil to operate the closing of the relay K1 contact, so that the dry contact provided with the relay K1 is turned on. If no pulse signal is output and the main controller fails to output a level signal, the second transistor Q2 is cut off, resulting in the dry contact working circuit 3 not forming a loop, the relay K1 contact is turned off, and the dry contact provided with the relay K1 is disconnected.

[0047] In summary, the above circuit can achieve stable control of the dry contacts in the battery management system, prevent the dry contacts from being in the on state all the time, ensure the normal state of the battery management system and the battery, and ensure the normal operation of the communication base station when the mains power is interrupted. In addition, the dry contact working circuit 3 is simple to implement and the device cost is low.

[0048] In one embodiment, the dry contact control circuit further includes:

[0049] The anti-backflow circuit 4 is provided on the line between the output end of the signal processing module and the dry contact driving circuit 2 , and is used to prevent the dry contact driving circuit 2 from outputting reverse current.

[0050] In this embodiment, the anti-backflow circuit 4 can be implemented by two diodes or a dual Schottky diode D1. Taking the dual Schottky diode D1 as an example, the first end of the dual Schottky diode D1 is electrically connected to the signal output end of the signal processing circuit 1, the second end of the dual Schottky diode D1 is electrically connected to the input end of the dry contact drive circuit 2, and the third end of the dual Schottky diode D1 is grounded. In this way, when the dry contact drive circuit 2 forms a loop, the current inside the loop can be prevented from being reversely output to the signal processing circuit 1, so that the dry contact control circuit can operate stably and reliably.

[0051] In one embodiment, the dry contact control circuit further includes:

[0052] The freewheeling circuit 5 is arranged on the line between the second power supply end of the battery management system and the dry contact working circuit 3, and is used to release the residual voltage of the dry contact working circuit 3 when the second power supply end of the battery management system stops supplying power.

[0053] In this embodiment, the freewheeling circuit 5 can use a common cathode switching diode D2, such as LBAV70LT1G. Taking this as an example, the first end of the common cathode switching diode D2 and the second end of the common cathode switching diode D2 are arranged on the line between the collector of the second transistor Q2 and the first end of the coil, and the third end of the common cathode switching diode D2 is electrically connected to the second power supply end of the battery management system. In this way, when the dry contact working circuit 3 forms a loop, the induced electromotive force generated by the coil can be absorbed to prevent it from damaging other components in the circuit. It can also release the generated reverse electromotive force when the current of the dry contact working circuit 3 suddenly changes or is interrupted, thereby improving the reliability of the dry contact working circuit 3.

[0054] The technical solution of the present utility model adopts a dry contact control circuit, which is applied to a battery management system. The battery management system is provided with a main controller, and the circuit includes: a signal processing circuit 1, wherein the signal input end of the signal processing circuit 1 is electrically connected to the pulse signal output end of the main controller, and the power input end of the signal processing circuit 1 is electrically connected to the first power supply end of the battery management system, and is used to receive and forward the pulse signal output by the main controller during normal operation. The signal processing circuit 1 is also used to filter the level signal output when the main controller fails; a dry contact driving circuit 2, wherein the signal input end of the dry contact driving circuit 2 is electrically connected to the signal output end of the signal processing module, and is used to generate and output a dry contact driving signal when receiving the forwarded pulse signal; a dry contact working circuit 3, wherein the controlled end of the dry contact working circuit 3 is electrically connected to the signal output end of the dry contact driving circuit 2, and the dry contact working circuit 3 is used to connect to the coil of the relay K1 and the second power supply end of the battery management system. The dry contact working circuit 3 is used to control the power supply end of the battery management system to power the coil according to the received driving signal, so as to control the relay K1 to turn on the dry contact. In this way, the dry contact control circuit can receive the pulse signal output by the main controller when it is working normally through the signal processing circuit 1 and forward it, and filter the level signal output when the main controller fails, so as to control the dry contact drive circuit 2 to drive the relay K1 to turn on the dry contact, so that the dry contact control circuit can prevent the dry contact from being in the on state all the time, so that when the controller malfunctions, the dry contact will be disconnected immediately.

[0055] The present utility model also proposes a battery management system, which includes a dry contact control circuit. The specific structure of the dry contact control circuit refers to the above-mentioned embodiment. Since the present battery management system adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0056] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A dry contact control circuit, applied to a battery management system, wherein the battery management system is provided with a main controller, characterized in that: The circuit comprises: a signal processing circuit, wherein the signal input end of the signal processing circuit is electrically connected to the pulse signal output end of the main controller, and the power input end of the signal processing circuit is electrically connected to the first power supply end of the battery management system, and is used to receive and forward the pulse signal output by the main controller when the main controller is operating normally, and the signal processing circuit is further used to filter the level signal output by the main controller when it fails; a dry contact driving circuit, wherein a signal input terminal of the dry contact driving circuit is electrically connected to a signal output terminal of the signal processing circuit, and is configured to generate and output a dry contact driving signal upon receiving a forwarded pulse signal; A dry contact working circuit, wherein the controlled end of the dry contact working circuit is electrically connected to the signal output end of the dry contact drive circuit, the dry contact working circuit is used to connect to the coil of the relay and the second power supply end of the battery management system, and the dry contact working circuit is used to control the power supply end of the battery management system to power the coil according to the received drive signal, so as to control the relay to turn on the dry contact.

2. The dry contact control circuit according to claim 1, wherein: The signal processing circuit includes a signal inversion circuit and a signal filtering circuit; a signal inversion circuit, wherein the signal input end of the signal inversion circuit is electrically connected to the pulse signal output end of the main controller, and the power input end of the signal inversion circuit is electrically connected to the first power supply end of the battery management system, and is used to forward the pulse signal output by the main controller when it is working normally; A signal filtering circuit, wherein the signal input end of the signal filtering circuit is electrically connected to the signal output end of the signal flipping circuit, and the signal output end of the signal filtering circuit is electrically connected to the signal input end of the dry contact driving circuit, and is used to filter the level signal output when the main controller fails.

3. The dry contact control circuit according to claim 2, wherein: The signal inversion circuit includes a first resistor, a second resistor, a third resistor and a first transistor; The pulse signal output end of the main controller is electrically connected to the first end of the first resistor and the first end of the second resistor, the second end of the second resistor is electrically connected to the first power supply end of the battery management system and the first end of the third resistor respectively, the second end of the third resistor is electrically connected to the signal input end of the signal filtering circuit and the collector of the first transistor, the base of the first transistor is electrically connected to the second end of the first resistor, and the emitter of the first transistor is grounded.

4. The dry contact control circuit according to claim 2, wherein: The signal filtering circuit includes a first capacitor, a first end of the first capacitor is electrically connected to the signal output end of the signal inversion circuit, and a second end of the first capacitor is electrically connected to the signal input end of the dry contact driving circuit.

5. The dry contact control circuit according to claim 1, wherein: The dry contact driving circuit includes a fourth resistor, a fifth resistor and a second capacitor; The first end of the fourth resistor, the first end of the fifth resistor and the first end of the second capacitor are respectively electrically connected to the signal output end of the signal processing circuit, the second end of the fifth resistor is electrically connected to the controlled end of the dry contact working circuit, and the second end of the fourth resistor and the second end of the fifth resistor are grounded.

6. The dry contact control circuit according to claim 1, wherein: The dry contact working circuit includes a second transistor and a third capacitor; The base of the second transistor is electrically connected to the signal output end of the dry contact drive circuit, the collector of the second transistor is electrically connected to the second power supply end of the battery management system and the first end of the coil, respectively, the first end of the third capacitor is electrically connected to the second end of the coil, and the emitter of the second transistor and the second end of the third capacitor are grounded.

7. The dry contact control circuit according to claim 1, wherein: The circuit further comprises: The anti-backflow circuit is arranged on the line between the output end of the signal processing circuit and the dry contact driving circuit, and is used to prevent the dry contact driving circuit from outputting reverse current.

8. The dry contact control circuit according to claim 7, wherein: The anti-backflow circuit includes a dual Schottky diode, a first end of the dual Schottky diode is electrically connected to the signal output end of the signal processing circuit, a second end of the dual Schottky diode is electrically connected to the input end of the dry contact drive circuit, and a third end of the dual Schottky diode is grounded.

9. The dry contact control circuit according to claim 1, wherein: The circuit further comprises: A freewheeling circuit is provided on a circuit between the second power supply end of the battery management system and the dry contact working circuit, and is used to release the residual voltage of the dry contact working circuit when the second power supply end of the battery management system stops supplying power.

10. A battery management system, characterized in that: The battery management system includes the dry contact control circuit according to claims 1 to 9.

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