Vehicle, negative electrode detection circuit, and battery management system

Abstract

The utility model discloses a vehicle, a cathode detection circuit and a battery management system, and the circuit comprises an isolation power supply module which is used for outputting a preset isolation voltage; the input end of the signal injection module is connected with the output end of the isolated power supply module, and the first output end is connected with one end of the main negative contactor; the first end of the detection module is connected with the second output end of the signal injection module, and the second end is connected with the other end of the main negative contactor, the negative electrode of the high-voltage battery pack and a grounding node; the power input end of the acquisition module is connected with the output end of the isolation power supply module, the acquisition end is connected with the third end of the detection module, the grounding end is connected with the other end of the main negative contactor, the negative electrode of the high-voltage battery pack and the grounding node, and the acquisition module obtains the current state of the main negative contactor according to the acquisition voltage of the third end of the detection module. Therefore, high-voltage cathode diagnosis is carried out by isolating the power supply signal without being influenced by the on-off time sequence of the switch, and the detection result is more accurate and reliable.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle detection, in particular to a vehicle, a negative electrode detection circuit and a battery management system. Background Art

[0002] As the power source of the vehicle, the power battery has the characteristics of high voltage, large capacity, and high power during charging and discharging. The smooth operation of the power battery benefits from the normal and orderly operation and control of the BMS (Battery Management System). Among them, the main negative contactor plays an important role in controlling the system switch and isolating the battery high voltage in the BMS. When the vehicle starts or stops, it is necessary to control the battery system by controlling the on and off of the main negative contactor to ensure that the vehicle's high-voltage battery is completely insulated from the outside to achieve safety. However, when the main negative contactor is disconnected, circuit adhesion will still occur, resulting in the high-voltage battery not being completely insulated from the outside, which is extremely dangerous. Therefore, it is particularly important to monitor the connectivity of the main negative contactor to ensure that the battery is in an insulated state when the main negative contactor is disconnected.

[0003] In the related art, a photocoupler switch is usually added by adding a jumper resistor from the front end to the back end of the relay to achieve the detection effect.

[0004] However, the related technology is easily affected by the switch opening and closing timing. If the switch opening and closing timing is not set properly, the circuit state will be unstable during the measurement process, thereby affecting the insulation detection results, which needs to be solved urgently. Utility Model Content

[0005] The utility model provides a vehicle, a negative pole detection circuit and a battery management system to solve the problem in the related art that when performing insulation detection through an optical coupling switch, the detection result is easily affected by the switch opening and closing timing, resulting in unstable detection results. The solution is simple and has high feasibility. Detection can be performed without entering the upper and lower high voltage processes, and it is not affected by the switch opening and closing timing, so the detection result is more accurate and reliable.

[0006] The first aspect of the utility model provides a negative electrode detection circuit, comprising:

[0007] An isolated power supply module for outputting a preset isolation voltage;

[0008] A signal injection module, wherein an input end of the signal injection module is connected to an output end of the isolation power module, and a first output end of the signal injection module is connected to one end of a main negative contactor;

[0009] A detection module, the first end of the detection module is connected to the second output end of the signal injection module, and the second end of the detection module is respectively connected to the other end of the main negative contactor, the negative pole of the high-voltage battery pack, and the grounding node;

[0010] An acquisition module, the power input end of the acquisition module is connected to the output end of the isolation power module, the acquisition end of the acquisition module is connected to the third end of the detection module, the grounding end of the acquisition module is respectively connected to the other end of the main negative contactor, the negative pole of the high-voltage battery pack, and the grounding node, and the acquisition module obtains the current state of the main negative contactor according to the acquisition voltage at the third end of the detection module.

[0011] Optionally, the signal injection module includes:

[0012] A first resistor, one end of the first resistor is connected to the output end of the isolation power module;

[0013] A first diode, the anode of the first diode is connected to the other end of the first resistor, and the cathode of the first diode is connected to one end of the main negative contactor.

[0014] Optionally, the detection module includes:

[0015] A second diode, the anode of the second diode is connected to the connection node between the first resistor and the first diode;

[0016] A second resistor, one end of the second resistor is connected to the cathode of the second diode, and the other end of the second resistor is connected to the acquisition end of the acquisition module;

[0017] A third resistor, one end of the third resistor is respectively connected to the other end of the second resistor and the acquisition end of the acquisition module, and the other end of the third resistor is respectively connected to the other end of the main negative contactor, the negative pole of the high-voltage battery pack, and the grounding node.

[0018] Optionally, the negative pole detection circuit further includes:

[0019] A first capacitor, one end of the first capacitor is connected to the connection node between the grounding end of the acquisition module and the other end of the third resistor;

[0020] A second capacitor, one end of the second capacitor is connected to the other end of the first capacitor, and the other end of the second capacitor is respectively connected to the cathode of the first diode and one end of the main negative contactor;

[0021] A third capacitor, one end of the third capacitor is respectively connected to the acquisition end of the acquisition module and one end of the third resistor, and the other end of the third capacitor is respectively connected to the grounding end of the acquisition module and the other end of the third resistor.

[0022] Optionally, the isolated power supply module includes:

[0023] A power supply component;

[0024] A DC-DC converter, the input end of the DC-DC converter is connected to the power supply component;

[0025] A transformer driver, the power input end of the transformer driver is connected to the output end of the DC-DC converter;

[0026] A transformer, the first end of the primary coil of the transformer is connected to the first output end of the transformer driver, the second end of the primary coil of the transformer is connected to the power input end of the transformer driver, and the third end of the primary coil of the transformer is connected to the second output end of the transformer driver;

[0027] A third diode, the anode of the third diode is connected to the first end of the secondary coil of the transformer, and the cathode of the third diode is connected to the output end of the isolated power supply module;

[0028] A fourth diode, the anode of the fourth diode is connected to the third end of the secondary coil of the transformer, and the cathode of the fourth diode is connected to the output end of the isolated power supply module;

[0029] A fourth capacitor, one end of the fourth capacitor is connected to the output end of the isolated power supply module, and the other end of the fourth capacitor is respectively connected to the grounding node and the second end of the secondary coil of the transformer;

[0030] A fifth capacitor, one end of the fifth capacitor is connected to the output end of the isolated power supply module, and the other end of the fifth capacitor is respectively connected to the grounding node and the second end of the secondary coil of the transformer;

[0031] A sixth capacitor, one end of the sixth capacitor is connected to the output end of the isolated power supply module, and the other end of the sixth capacitor is respectively connected to the grounding node and the second end of the secondary coil of the transformer;

[0032] A seventh capacitor, one end of the seventh capacitor is connected to the power input end of the transformer driver, and the other end of the seventh capacitor is connected to the grounding node.

[0033] Optionally, the power supply component is a 12V storage battery.

[0034] Optionally, the negative electrode detection circuit further includes:

[0035] An identification module, connected to the acquisition module, for identifying whether the current state of the main negative contactor is consistent with the target state of the main negative contactor;

[0036] A reminder module, connected to the identification module, for giving an alarm reminder when the current state of the main negative contactor is inconsistent with the target state of the main negative contactor.

[0037] Optionally, the reminder module includes:

[0038] An acoustic reminder unit, connected to the identification module, for giving an acoustic reminder when the current state of the main negative contactor is inconsistent with the target state of the main negative contactor;

[0039] An optical reminder unit, connected to the identification module, for giving an optical reminder when the current state of the main negative contactor is inconsistent with the target state of the main negative contactor.

[0040] A second aspect of the present invention provides a battery management system, which includes the above-mentioned negative electrode detection circuit.

[0041] A third aspect of the present invention provides a vehicle, which includes the above-mentioned battery management system.

[0042] Thus, by isolating the 5V voltage injection through the isolation power module and the signal injection module and performing resistor voltage division to determine the opening and closing state of the main negative contactor, and detecting whether there are open circuit or relay adhesion problems, the problem that the detection result is unstable due to the influence of the switch opening and closing timing when using an optocoupler switch for insulation detection in the related art is solved. The solution is simple, highly feasible, can be detected without entering the high-voltage up and down process, and is not affected by the switch opening and closing timing, and the detection result is more accurate and reliable.

[0043] Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be understood through the practice of the present invention. Description of the Drawings

[0044] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0045] Figure 1 It is a schematic structural diagram of a negative electrode detection circuit according to an embodiment of the present invention;

[0046] Figure 2 Schematic diagram of a negative electrode detection circuit provided according to a specific embodiment of the present utility model;

[0047] Figure 3 Schematic diagram of the structure of externally supplied power according to a specific embodiment of the present utility model;

[0048] Figure 4 Schematic diagram of the 5V output circuit of the isolated power supply module according to a specific embodiment of the present utility model.

[0049] Reference numerals:

[0050] 10 - Negative electrode detection circuit, 100 - Isolated power supply module, 101 - Power supply component, 102 - DC - DC converter, 103 - Transformer driver, 104 - Transformer, 105 - Third diode, 106 - Fourth diode, 107 - Fourth capacitor, 108 - Fifth capacitor, 109 - Sixth capacitor, 110 - Seventh capacitor, 200 - Signal injection module, 201 - First resistor, 202 - First diode, 300 - Detection module, 301 - Second diode, 302 - Second resistor, 303 - Third resistor, 400 - Wiring component, 501 - First capacitor, 502 - Second capacitor, 503 - Third capacitor. Detailed description of the embodiments

[0051] The embodiments of the present utility model will be described in detail below. The examples of the embodiments are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described by referring to the drawings below are exemplary and are intended to explain the present utility model, and should not be construed as a limitation to the present utility model.

[0052] The vehicle, negative electrode detection circuit and battery management system according to the embodiments of the present utility model will be described below with reference to the drawings. Aiming at the problem in the related art mentioned in the above - mentioned background technology that the insulation detection by the opto - coupler switch is easily affected by the switch opening and closing timing, resulting in unstable detection results, the embodiments of the present utility model propose a negative electrode detection circuit, which performs high - voltage negative electrode diagnosis on the main negative contactor through an isolated power signal, solves the problem that the insulation detection in the related technology is easily affected by the switch opening and closing timing, resulting in unstable detection results. The solution is not only simple and highly feasible, but also can perform the detection without entering the high - voltage up - and - down process, and is not affected by the switch opening and closing timing, and the detection results are more accurate and reliable.

[0053] Specifically, Figure 1 Schematic diagram of the structure of a negative electrode detection circuit provided according to an embodiment of the present utility model.

[0054] As Figure 1As shown, the negative electrode detection circuit 10 includes: an isolated power supply module 100, a signal injection module 200, a detection module 300, and a collection module 400.

[0055] Among them, the isolated power supply module 100 is used to output a preset isolated voltage; for the signal injection module 200, the input end of the signal injection module 200 is connected to the output end of the isolated power supply module 100, and the first output end of the signal injection module 200 is connected to one end of the main negative contactor; for the detection module 300, the first end of the detection module 300 is connected to the second output end of the signal injection module 200, and the second end of the detection module 300 is respectively connected to the other end of the main negative contactor, the negative electrode of the high-voltage battery pack, and the grounding node; for the collection module 400, the power input end of the collection module 400 is connected to the output end of the isolated power supply module 100, the collection end of the collection module 400 is connected to the third end of the detection module 300, and the grounding end of the collection module 400 is respectively connected to the other end of the main negative contactor, the negative electrode of the high-voltage battery pack, and the grounding node. The collection module 400 obtains the current state of the main negative contactor according to the collected voltage at the third end of the detection module 300.

[0056] Specifically, the isolated power supply module 100 generates a 5V isolated power supply. The 5V low-voltage power is injected into the outside of the detection module 200, the collection module 400, and the main negative contactor through the signal injection module. The outside collected voltage of the main negative contactor is measured through the detection module 300 and the collection module 400, and the on-off condition of the main negative contactor is judged, achieving the effect of high-voltage negative electrode diagnosis.

[0057] Optionally, in some embodiments, the signal injection module 200 includes: a first resistor 201 and a first diode 202. Among them, one end of the first resistor 201 is connected to the output end of the isolated power supply module; the anode of the first diode 202 is connected to the other end of the first resistor 201, and the cathode of the first diode 202 is connected to one end of the main negative contactor.

[0058] Specifically, as Figure 2 shown, Figure 2 is a schematic diagram of the negative electrode detection circuit according to a specific embodiment of the present invention. Among them, the first resistor 201 can be a 100k resistor, the first diode 201 can be an anti-reverse diode with a withstand voltage of 1500V. One end of the first resistor 201 is connected to the output end of the isolated power supply module 100, the other end is connected to the anode of the first diode 202, the cathode of the first diode 202 is connected to the main negative contactor, and the 5V voltage output by the isolated power supply module 100 is injected into the outside of the main negative contactor through the first resistor 201 and the first diode 202.

[0059] As a possible implementation manner, in some embodiments, the detection module 300 includes: a second diode 301, a second resistor 302, and a third resistor 303. Among them, the anode of the second diode 301 is connected to the connection node between the first resistor 201 and the first diode 202; one end of the second resistor 302 is connected to the cathode of the second diode 301, and the other end of the second resistor 302 is connected to the acquisition end of the acquisition module 400; one end of the third resistor 303 is respectively connected to the other end of the second resistor 302 and the acquisition end of the acquisition module 400, and the other end of the third resistor 303 is respectively connected to the other end of the main negative contactor, the negative electrode of the high-voltage battery pack, and the ground node.

[0060] Specifically, the anode of the second diode 301 is connected to the first resistor 201 and the first diode 202, which is used to cancel the voltage of the first diode 202, facilitate calculation, and avoid interference caused by reverse current passing through the detection module 300. The second resistor 302 is connected to the cathode of the second diode 301, and the other end is connected to the acquisition end of the acquisition module 400; the 5V isolated voltage of the isolated power supply module 100 enters the detection module 300 through the signal injection module 200. After the resistance voltage division in the detection module 300, the target acquisition voltage outside the main negative contactor can be calculated. By acquiring the acquisition voltage of the main negative contactor through the acquisition module 400 and comparing it with the target voltage, the on-off state of the main negative contactor can be determined.

[0061] Exemplarily, when the first resistor 201 is a 100K resistor, the second resistor 302 and the third resistor 303 are 56K resistors, and the first diode 201 is a 1500V reverse protection diode, if the main negative contactor is disconnected, the first diode 201 is floating, and at this time, the target acquisition voltage Vad outside the main negative contactor is Vad=(5V - D2) / (R1 + R2 + R3)*R3≈1v; if the main negative contactor is closed, the first diode 201 is connected to the high-voltage negative electrode. At this time, the voltage drop VF of the first diode 201 is approximately 1v, and the voltage drop of the second diode 301 is also approximately VF≈1v. At this time, since the third resistor 303 is grounded, all the target acquisition voltage Vad≈0. Therefore, the target acquisition voltage should be less than 200mv.

[0062] Optionally, in some embodiments, the negative electrode detection circuit 10 further includes: a first capacitor 501, a second capacitor 502, and a third capacitor 503. One end of the first capacitor 501 is connected to the connection node between the ground terminal of the acquisition module 400 and the other end of the third resistor 303; one end of the second capacitor 502 is connected to the other end of the first capacitor 501, and the other end of the second capacitor 502 is respectively connected to the cathode of the first diode 202 and one end of the main negative contactor; one end of the third capacitor 503 is respectively connected to the acquisition terminal of the acquisition module 400 and one end of the third resistor 303, and the other end of the third capacitor 503 is respectively connected to the ground terminal of the acquisition module 400 and the other end of the third resistor 303.

[0063] Specifically, the first capacitor 501, the second capacitor 502, and the third capacitor 503 together form a transient filtering circuit, which can effectively suppress high-frequency interference signals in the power supply, prevent the interference signals from affecting the detection module and the acquisition module, and improve the stability and reliability of the negative electrode detection circuit.

[0064] Optionally, in some embodiments, the isolated power supply module 100 includes: a power supply component, a DC-DC converter, a transformer driver, a transformer, a third diode, a fourth diode, a fourth capacitor, a fifth capacitor, a sixth capacitor, and a seventh capacitor. The input end of the DC-DC converter is connected to the power supply component; the power input end of the transformer driver is connected to the output end of the DC-DC converter; the first end of the primary coil of the transformer is connected to the first output end of the transformer driver, the second end of the primary coil of the transformer is connected to the power input end of the transformer driver, and the third end of the primary coil of the transformer is connected to the second output end of the transformer driver; the anode of the third diode is connected to the first end of the secondary coil of the transformer, and the cathode of the third diode is connected to the output end of the isolated power supply module; the anode of the fourth diode is connected to the third end of the secondary coil of the transformer, and the cathode of the fourth diode is connected to the output end of the isolated power supply module; one end of the fourth capacitor is connected to the output end of the isolated power supply module, and the other end of the fourth capacitor is respectively connected to the ground node and the second end of the secondary coil of the transformer; one end of the fifth capacitor is connected to the output end of the isolated power supply module, and the other end of the fifth capacitor is respectively connected to the ground node and the second end of the secondary coil of the transformer; one end of the sixth capacitor is connected to the output end of the isolated power supply module, and the other end of the sixth capacitor is respectively connected to the ground node and the second end of the secondary coil of the transformer; one end of the seventh capacitor is connected to the power input end of the transformer driver, and the other end of the seventh capacitor is connected to the ground node.

[0065] Among them, in some embodiments, the power supply component is a 12V storage battery.

[0066] Specifically, as Figure 3 and Figure 4As shown in the figure, where Figure 3 is a schematic structural diagram of externally powered according to a specific embodiment of the present invention. Figure 4 is a schematic diagram of the 5V output circuit of the isolated power supply module according to a specific embodiment of the present invention. Among them, the power supply component 101 is a 12V battery, and the transformer driver 103 can be an SN6505 chip. The 12V voltage output by the power supply component 101 powers the entire isolated power supply module 100, and after passing through the filter circuit and the DC-DC converter 102 circuit, 5V voltage is output to power the isolated power supply module 100. The isolated power supply module 100 generates a 5V isolated power supply for the detection module 300 to use; the external 12V power supply passes through the SN6505 chip of the transformer driver 103 and then passes through the transformer 104 for 1:1 output. After rectifying the alternating current through the third diode 105 and the fourth diode 106, direct current is output. The fourth capacitor 107, the fifth capacitor 108, the sixth capacitor 109, and the seventh capacitor 110 jointly protect the output circuit of the isolated power supply module to prevent damage to the circuit and components caused by overcurrent, and at the same time, filter out interfering currents.

[0067] Optionally, in some embodiments, the negative pole detection circuit 10 further includes: an identification module and a reminder module. Among them, the identification module is connected to the acquisition module and is used to identify whether the current state of the main negative contactor is consistent with the target state of the main negative contactor; the reminder module is connected to the identification module, and the reminder module gives an alarm reminder when the current state of the main negative contactor is inconsistent with the target state of the main negative contactor.

[0068] As a possible implementation method, in some embodiments, the reminder module includes: an acoustic reminder unit and an optical reminder unit. Among them, the acoustic reminder unit is connected to the identification module, and the acoustic reminder unit gives an acoustic reminder when the current state of the main negative contactor is inconsistent with the target state of the main negative contactor; the optical reminder unit is connected to the identification module, and the optical reminder unit gives an optical reminder when the current state of the main negative contactor is inconsistent with the target state of the main negative contactor.

[0069] Specifically, when the identification module identifies that the current state of the main negative contactor is inconsistent with the target state, it triggers the acoustic reminder unit and the optical reminder unit to give a reminder to the user. For example, the acoustic reminder unit issues an alarm sound of "the main negative contactor fails" or a beeping alarm through the vehicle control system or the microphone; the optical reminder unit displays the words "the main negative contactor fails" on the main display screen of the vehicle control system to remind the user.

[0070] In summary, the negative electrode detection circuit of the present utility model measures the acquisition voltage outside the main negative contactor through the detection module and the acquisition module, determines the opening and closing state of the main negative contactor, and gives a reminder to the user when the opening and closing state of the main negative contactor is abnormal, enabling the user to be aware in time and ensuring the personal safety of the user.

[0071] According to the negative electrode detection circuit proposed by the embodiment of the present utility model, the 5V voltage injection is isolated through the isolated power supply module and the signal injection module and is subjected to resistor voltage division to determine the opening and closing state of the main negative contactor, and to detect whether there are problems such as open circuit or relay adhesion, solving the problem in the related art that the detection result is unstable due to being easily affected by the switch opening and closing timing when using an optocoupler switch for insulation detection. The solution is simple, highly feasible, can be detected without entering the high-voltage up and down process, is not affected by the switch opening and closing timing, and the detection result is more accurate and reliable.

[0072] On the other hand, the present utility model also provides a battery management system, and the battery management system includes the above-mentioned negative electrode detection circuit.

[0073] According to the battery management system proposed by the present utility model, the 5V voltage injection is isolated through the isolated power supply module and the signal injection module and is subjected to resistor voltage division to determine the opening and closing state of the main negative contactor, and to detect whether there are problems such as open circuit or relay adhesion, solving the problem in the related art that the detection result is unstable due to being easily affected by the switch opening and closing timing when using an optocoupler switch for insulation detection. The solution is simple, highly feasible, can be detected without entering the high-voltage up and down process, is not affected by the switch opening and closing timing, and the detection result is more accurate and reliable.

[0074] In addition, the embodiment of the present utility model also provides a vehicle, and the vehicle includes the above-mentioned battery management system.

[0075] According to the vehicle proposed by the present utility model, the 5V voltage injection is isolated through the isolated power supply module and the signal injection module and is subjected to resistor voltage division to determine the opening and closing state of the main negative contactor, and to detect whether there are problems such as open circuit or relay adhesion, solving the problem in the related art that the detection result is unstable due to being easily affected by the switch opening and closing timing when using an optocoupler switch for insulation detection. The solution is simple, highly feasible, can be detected without entering the high-voltage up and down process, is not affected by the switch opening and closing timing, and the detection result is more accurate and reliable.

[0076] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or N embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0077] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically defined.

Claims

1. A negative electrode detection circuit, characterized in that Comprising: An isolated power supply module for outputting a preset isolation voltage; A signal injection module, the input end of the signal injection module is connected to the output end of the isolated power supply module, and the first output end of the signal injection module is connected to one end of the main negative contactor; A detection module, the first end of the detection module is connected to the second output end of the signal injection module, and the second end of the detection module is respectively connected to the other end of the main negative contactor, the negative electrode of the high-voltage battery pack, and the grounding node; An acquisition module, the power input end of the acquisition module is connected to the output end of the isolated power supply module, the acquisition end of the acquisition module is connected to the third end of the detection module, and the grounding end of the acquisition module is respectively connected to the other end of the main negative contactor, the negative electrode of the high-voltage battery pack, and the grounding node. The acquisition module obtains the current state of the main negative contactor according to the acquired voltage at the third end of the detection module.

2. The negative electrode detection circuit according to claim 1, wherein The signal injection module includes: A first resistor, one end of the first resistor is connected to the output end of the isolated power supply module; A first diode, the anode of the first diode is connected to the other end of the first resistor, and the cathode of the first diode is connected to one end of the main negative contactor.

3. The negative electrode detection circuit according to claim 2, wherein The detection module includes: A second diode, the anode of the second diode is connected to the connection node between the first resistor and the first diode; A second resistor, one end of the second resistor is connected to the cathode of the second diode, and the other end of the second resistor is connected to the acquisition end of the acquisition module; A third resistor, one end of the third resistor is respectively connected to the other end of the second resistor and the acquisition end of the acquisition module, and the other end of the third resistor is respectively connected to the other end of the main negative contactor, the negative electrode of the high-voltage battery pack, and the grounding node.

4. The negative electrode detection circuit according to claim 3, characterized in that, It further includes: A first capacitor, one end of the first capacitor is connected to the connection node between the grounding end of the acquisition module and the other end of the third resistor; A second capacitor, one end of the second capacitor is connected to the other end of the first capacitor, and the other end of the second capacitor is respectively connected to the cathode of the first diode and one end of the main negative contactor; A third capacitor, one end of the third capacitor is respectively connected to the acquisition end of the acquisition module and one end of the third resistor, and the other end of the third capacitor is respectively connected to the grounding end of the acquisition module and the other end of the third resistor.

5. The negative electrode detection circuit according to any one of claims 1-4, characterized in that, The isolated power supply module includes: A power supply component; A DC-DC converter, the input end of the DC-DC converter is connected to the power supply component; A transformer driver, the power input end of the transformer driver is connected to the output end of the DC-DC converter; A transformer, the first end of the primary coil of the transformer is connected to the first output end of the transformer driver, the second end of the primary coil of the transformer is connected to the power input end of the transformer driver, and the third end of the primary coil of the transformer is connected to the second output end of the transformer driver; A third diode, an anode of the third diode is connected to a first end of a secondary coil of the transformer, and a cathode of the third diode is connected to an output end of the isolated power supply module; A fourth diode, an anode of the fourth diode is connected to a third end of the secondary coil of the transformer, and a cathode of the fourth diode is connected to the output end of the isolated power supply module; A fourth capacitor, one end of the fourth capacitor is connected to the output end of the isolated power supply module, and the other end of the fourth capacitor is respectively connected to the ground node and a second end of the secondary coil of the transformer; A fifth capacitor, one end of the fifth capacitor is connected to the output end of the isolated power supply module, and the other end of the fifth capacitor is respectively connected to the ground node and a second end of the secondary coil of the transformer; A sixth capacitor, one end of the sixth capacitor is connected to the output end of the isolated power supply module, and the other end of the sixth capacitor is respectively connected to the ground node and a second end of the secondary coil of the transformer; A seventh capacitor, one end of the seventh capacitor is connected to a power input end of the transformer driver, and the other end of the seventh capacitor is connected to the ground node.

6. The negative electrode detection circuit according to claim 5, wherein The power supply component is a 12V storage battery.

7. The negative electrode detection circuit according to claim 1, characterized in that, Further comprising: An identification module, the identification module is connected to the acquisition module, and the identification module is used to identify whether the current state of the main negative contactor is consistent with the target state of the main negative contactor; A reminder module, the reminder module is connected to the identification module, and the reminder module gives an alarm reminder when the current state of the main negative contactor is inconsistent with the target state of the main negative contactor.

8. The negative electrode detection circuit according to claim 7, wherein The reminder module includes: An acoustic reminder unit, the acoustic reminder unit is connected to the identification module, and the acoustic reminder unit gives an acoustic reminder when the current state of the main negative contactor is inconsistent with the target state of the main negative contactor; An optical reminder unit, the optical reminder unit is connected to the identification module, and the optical reminder unit gives an optical reminder when the current state of the main negative contactor is inconsistent with the target state of the main negative contactor.

9. A battery management system, characterized in that, Comprising: The negative electrode detection circuit according to any one of claims 1-8.

10. A vehicle, characterized in that, Comprising: The battery management system according to claim 9.

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