Voltage monitoring circuit, body control module, power supplement system and vehicle

Abstract

The application discloses a voltage monitoring circuit, a vehicle body control module, a power supply system and a vehicle, and belongs to the technical field of low-voltage storage batteries of vehicles, and comprises a voltage dividing unit, the voltage dividing unit comprising a first voltage dividing resistor and a second voltage dividing resistor, one end of the first voltage dividing resistor being used for being connected with a low-voltage storage battery, the other end of the first voltage dividing resistor being connected with the second voltage dividing resistor, and the resistance value of the first voltage dividing resistor being smaller than the resistance value of the second voltage dividing resistor; a voltage follower unit, a first input end of the voltage follower unit being connected between the first voltage dividing resistor and the second voltage dividing resistor; a limiting unit, the limiting unit being connected with the first input end of the voltage follower unit; and a monitoring chip, the monitoring chip being connected with an output end of the voltage follower unit. The voltage monitoring circuit provided by the application can monitor the specific voltage of the low-voltage storage battery, and the circuit structure is simple.

Description

Technical Field

[0001] This application relates to the field of low-voltage battery technology for vehicles, and more particularly to a voltage monitoring circuit, a body control module, a charging system, and a vehicle. Background Technology

[0002] Electric vehicles have a power battery and a low-voltage battery. The power battery provides high-voltage electrical energy to power the vehicle and high-voltage electrical appliances; the low-voltage battery powers the vehicle's low-voltage electrical appliances and systems. The low-voltage battery in an electric vehicle is replenished by the power battery. However, current monitoring circuits mainly focus on monitoring the overvoltage and undervoltage states of the low-voltage battery, and cannot monitor the specific voltage of the low-voltage battery. Utility Model Content

[0003] A voltage monitoring circuit, a body control module, a power supply system, and a vehicle are provided to address the aforementioned technical issues.

[0004] To achieve the above objectives, in a first aspect, embodiments of this application provide a voltage monitoring circuit, comprising: The voltage divider unit includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is connected to a low-voltage battery, and the other end of the first voltage divider resistor is connected to the second voltage divider resistor. The resistance of the first voltage divider resistor is greater than the resistance of the second voltage divider resistor. A voltage follower unit, wherein the first input terminal of the voltage follower unit is connected between the first voltage divider resistor and the second voltage divider resistor; A limiting unit is connected to the first input terminal of the voltage follower unit; A monitoring chip is connected to the output terminal of the voltage follower unit.

[0005] In conjunction with the first aspect, the voltage follower unit includes an operational amplifier having a first input terminal, a second input terminal, a positive power supply terminal, a negative power supply terminal, and an output terminal. The second input terminal is connected to the output terminal, the positive power supply terminal is connected to a voltage source, and the negative power supply terminal is grounded.

[0006] In conjunction with the first aspect, the voltage follower unit further includes a feedback resistor connected between the second input terminal and the output terminal of the operational amplifier.

[0007] In conjunction with the first aspect, it also includes a current-limiting resistor connected to the output terminal of the operational amplifier.

[0008] In conjunction with the first aspect, the limiting unit includes a first diode and a second diode, the cathode of the first diode is connected to a voltage source, the anode of the first diode is connected to the anode of the second diode, the cathode of the second diode is grounded, and the anode of the first diode is also connected to the first input terminal.

[0009] In conjunction with the first aspect, the reverse current of the first diode is equal to that of the second diode.

[0010] In conjunction with the first aspect, the first voltage divider resistor has a first resistance value M1, and the second voltage divider resistor has a second resistance value M2, satisfying: 1 / 6≤M2 / (M1+M2)≤1 / 4.

[0011] Secondly, embodiments of this application provide a vehicle body control module, which includes a voltage monitoring circuit as described in any one of the first aspects.

[0012] Thirdly, embodiments of this application provide a power replenishment system, including: Low-voltage batteries; A DC-DC converter module, wherein the DC-DC converter module is connected to the low-voltage battery; A high-voltage storage battery, which is connected to the DC-DC conversion module; Command sending module, the command sending module being connected to the high-voltage storage battery; and The body control module as described in the second aspect is connected to the low-voltage battery and the command sending module.

[0013] Fourthly, embodiments of this application provide a vehicle including the charging system described in the third aspect.

[0014] One of the above technical solutions has the following advantages or beneficial effects: This application provides a voltage monitoring circuit, including: a voltage divider unit, comprising a first voltage divider resistor and a second voltage divider resistor, one end of the first voltage divider resistor being connected to a low-voltage battery, and the other end of the first voltage divider resistor being connected to the second voltage divider resistor, wherein the resistance of the first voltage divider resistor is less than the resistance of the second voltage divider resistor; a voltage follower unit, the first input terminal of which is connected between the first and second voltage divider resistors; a limiting unit, connected to the first input terminal of the voltage follower unit; and a monitoring chip, connected to the output terminal of the voltage follower unit. The voltage monitoring circuit provided in this application can monitor the specific voltage of a low-voltage battery, and the circuit structure is simple. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the module connection of the voltage monitoring circuit according to an embodiment of this application; Figure 2 This is a schematic diagram of the connection structure of the voltage monitoring circuit according to an embodiment of this application; Figure 3 This is a schematic diagram of the module connection of the power supply system according to an embodiment of this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0018] Furthermore, descriptions involving "first," "second," etc., in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0019] Those skilled in the art noted that when a vehicle is stationary, it enters a dormant state. During this phase, the high-voltage battery is not operational, and the low-voltage battery is not recharged. If the vehicle is parked for an extended period, the low-voltage battery will continuously deplete, causing its charge to gradually decrease. If the low-voltage battery's charge becomes too low, it can lead to various vehicle malfunctions. During this period, the low-voltage battery voltage is periodically monitored. If the voltage is detected to be below a set threshold, a recharge request is sent from the BCM (Body Control Module) to the VCU (Vehicle Control Unit). The VCU then activates the high-voltage battery to recharge the low-voltage battery based on the recharge request.

[0020] The following is a detailed description of the technical solutions provided in the embodiments of this application: like Figure 1 As shown in the illustration, this application proposes a voltage monitoring circuit, including: a voltage divider unit, comprising a first voltage divider resistor R1 and a second voltage divider resistor R2, one end of the first voltage divider resistor R1 being connected to a low-voltage battery, and the other end of the first voltage divider resistor R1 being connected to the second voltage divider resistor R2, wherein the resistance value of the first voltage divider resistor R1 is greater than the resistance value of the second voltage divider resistor R2; a voltage follower unit, the first input terminal of which is connected between the first voltage divider resistor R1 and the second voltage divider resistor R2; a limiting unit, which is connected to the first input terminal of the voltage follower unit; and a monitoring chip, which is connected to the output terminal of the voltage follower unit. Specifically, the first voltage divider resistor R1 and the second voltage divider resistor R2 are connected in series to the positive terminal of the low-voltage battery, while the other end of the second voltage divider resistor R2 is grounded. By controlling the resistance relationship between the first voltage divider resistor R1 and the second voltage divider resistor R2, the node voltage between the first voltage divider resistor R1 and the second voltage divider resistor R2 can be controlled. This is to ensure that the voltage of the input voltage follower unit and the monitoring chip is controlled within a safe range. The resistance of the second voltage divider resistor R2 is set to be smaller than that of the first voltage divider resistor R1, resulting in a larger voltage across the first voltage divider resistor R1 and a smaller voltage across the second voltage divider resistor R2. This reduces the node voltage between the first and second voltage divider resistors R1 and R2. The voltage gain of the voltage follower unit is 1, and its main function is to change the impedance characteristics of the signal, solving the problem of insufficient load-carrying capacity of the preceding circuit. Connecting the voltage follower unit between the low-voltage battery and the monitoring chip, due to its extremely high input impedance, results in an almost no-load condition for the low-voltage battery. The current signal output by the low-voltage battery can be completely transmitted to the input of the voltage follower unit, avoiding signal attenuation or distortion. The high input impedance of the voltage follower unit can block interference from the monitoring chip, while the low output impedance can absorb interference from the monitoring chip itself. This is equivalent to establishing an impedance barrier between the low-voltage battery and the monitoring chip, ensuring the stability of the low-voltage battery signal and that the monitoring chip's operation is not limited by the low-voltage battery.

[0021] In this embodiment, a limiting unit is connected between the voltage divider unit and the first input terminal of the voltage follower unit to limit the voltage input to the voltage follower unit. When the voltage between the voltage divider unit and the first input terminal is less than the safe voltage set by the limiting unit, the limiting unit is in the off state, and the current signal is normally input to the voltage follower unit. When the voltage between the voltage divider unit and the first input terminal is greater than or equal to the safe voltage set by the limiting unit, the limiting unit is turned on, and the current signal flows to the limiting unit, thereby preventing high voltage from damaging the voltage follower unit.

[0022] In this embodiment, the monitoring chip is used to deduce the specific voltage of the low-voltage battery based on the input voltage. A calculation formula can be preset in the monitoring chip; substituting the measured voltage into the formula yields the specific voltage of the low-voltage battery.

[0023] It is understood that the voltage monitoring circuit provided in this application embodiment can monitor the specific voltage of the low-voltage battery, and the circuit has a simple structure and a wide monitoring range.

[0024] like Figure 2 As shown in this embodiment, the first voltage divider resistor R1 has a first resistance value M1, and the second voltage divider resistor R2 has a second resistance value M2, satisfying: 1 / 6 ≤ M2 / (M1+M2) ≤ 1 / 4. Specifically, the voltage range of a typical low-voltage battery is 9V to 16V, while the voltage follower unit and detection chip can withstand a maximum voltage of 5V. To monitor the voltage of the low-voltage battery and avoid excessive voltage on the voltage follower unit and detection chip, when the low-voltage battery voltage is 16V, based on the resistance relationship between the first voltage divider resistor R1 and the second voltage divider resistor R2, the voltage of the divided battery can be determined to be 2.67V-4V, both less than the maximum voltage that the voltage follower unit and detection chip can withstand (5V).

[0025] It is understandable that by controlling the relationship between the first voltage divider resistor R1 and the second voltage divider resistor R2, the voltage acquisition range of the low-voltage battery can be adjusted so that even when the low-voltage battery is fully charged, the voltage of the input voltage follower unit and the detection chip can be reduced by voltage division, thereby protecting the voltage follower unit and the detection chip.

[0026] like Figure 2 As shown in this embodiment, the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 are both greater than 100KΩ and less than or equal to 500KΩ. Specifically, by controlling the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 between 100KΩ and 500KΩ, the current in the voltage monitoring circuit is controlled. When the battery is fully charged, the voltage is 16V. If the resistance value of the first voltage divider resistor R1 is 100KΩ and the resistance value of the second voltage divider resistor R2 is 400KΩ, then the maximum current is 32μA. The resistance accuracy of the first voltage divider resistor R1 and the second voltage divider resistor R2 is selected as 0.1%.

[0027] It is understandable that controlling the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 serves to limit the current in the circuit.

[0028] like Figure 2As shown in this embodiment, the voltage follower unit includes an operational amplifier U1. Operational amplifier U1 has a first input terminal, a second input terminal, a positive power supply terminal, a negative power supply terminal, and an output terminal. The second input terminal is connected to the output terminal, the positive power supply terminal is connected to a voltage source, and the negative power supply terminal is grounded. Specifically, the first input terminal is the non-inverting input terminal of operational amplifier U1, and the second input terminal is the non-inverting input terminal of operational amplifier U1. The voltage follower unit has high input impedance and low input current; therefore, the voltage drop across the first voltage divider resistor R1 and the second voltage divider resistor R2 is small. If the voltage follower unit is removed and the voltage divider unit is directly connected to the monitoring chip, leakage current will exist at the port of the monitoring chip, resulting in a voltage drop across the first voltage divider resistor R1 due to leakage current, causing excessive error in the voltage monitoring circuit.

[0029] Understandably, by setting up a voltage follower unit, the influence of leakage current at the monitoring chip port on the voltage monitoring circuit can be eliminated, thereby improving the monitoring accuracy of the voltage monitoring circuit and accurately determining the specific voltage value of the low-voltage battery.

[0030] like Figure 2 As shown in this embodiment, the voltage follower unit further includes a feedback resistor R3, which is connected between the second input terminal and the output terminal of the operational amplifier U1. Specifically, the operational amplifier U1 itself generates noise (such as voltage noise and current noise), and external environments may also introduce interference (such as power supply ripple and electromagnetic interference). By setting the feedback resistor R3 for error correction, the effects of noise and interference are equivalent to the input terminal, and the controllability of the closed-loop gain reduces the proportion of noise at the output terminal.

[0031] It is understandable that the main purpose of setting a feedback resistor R3 between the negative input terminal and the output terminal of operational amplifier U1 is to construct a negative feedback loop. Through the negative feedback circuit, the operating state and output characteristics of operational amplifier U1 can be precisely controlled.

[0032] like Figure 2As shown, this embodiment also includes a current-limiting resistor R4, which is connected to the output terminal of operational amplifier U1. Specifically, operational amplifier U1 has a limited output current capability. If the output terminal is directly connected to the monitoring chip, the output current will far exceed the rated value of operational amplifier U1, causing the operational amplifier U1 chip to overheat and burn out, or triggering the internal overcurrent protection. Frequent triggering will affect its lifespan. By connecting the current-limiting resistor R4 in series in the output circuit, the maximum output current is limited to the safe range of operational amplifier U1, preventing damage to operational amplifier U1. Furthermore, monitoring chips usually also have a rated current limit. Directly driving them with operational amplifier U1 may burn out the monitoring chip due to excessive current. By connecting the current-limiting resistor R4, the current flowing into the monitoring chip is stabilized within the rated value of the monitoring chip, preventing the monitoring chip from being damaged by overcurrent.

[0033] Understandably, the current-limiting resistor R4 serves as a protection device at the output of operational amplifier U1, limiting the output current of operational amplifier U1. This not only protects operational amplifier U1 itself but also the monitoring chip.

[0034] like Figure 2As shown in the embodiment of this application, the limiting unit includes a first diode D1 and a second diode D2. The cathode of the first diode D1 is connected to a voltage source, the anode of the first diode D1 is connected to the anode of the second diode D2, the cathode of the second diode D2 is grounded, and the anode of the first diode D1 is also connected to the first input terminal. Specifically, the first diode D1 and the second diode D2 are actually connected in series in the same direction. The cathode of the first diode D1 is connected to a 5V voltage source V1, the anode of the second diode D2 is grounded, and the anode of the first diode D1 and the cathode of the second diode D2 are interconnected and connected to the non-inverting input terminal of the operational amplifier U1. It is worth noting that diodes with small reverse current and forward voltage drop are selected. Through the combination of the first diode D1 and the second diode, the voltage at the non-inverting input terminal of the operational amplifier U1 is limited to between -VF and 5+VF to protect against short-term high voltage from low-voltage battery load dump and negative voltage during reverse connection. When a low-voltage battery generates 36V under load conditions, the voltage is controlled between 6V and 9V after passing through the voltage divider unit. If this voltage is directly input to the non-inverting input of operational amplifier U1, U1 will be damaged due to overvoltage. However, by connecting 5V to the cathode of the first diode D1, the voltage difference between 6V-9V and 5V causes the first diode D1 to conduct, thus limiting the voltage input to the operational amplifier to 5V+VF, thereby protecting operational amplifier U1. When the power supply polarity is reversed and the power supply voltage is between -16V and -9V, the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 satisfy: 3 / 4≤M1 / (M1+M2)≤5 / 6. Therefore, after passing through the voltage divider unit, the voltage range between the first voltage divider resistor R1 and the second voltage divider resistor R2 is: -16V*(5 / 6) to -9V*(3 / 4), which is -13.3V to -6.75V. If the voltage is directly applied to the non-inverting input of operational amplifier U1, U1 may be damaged due to excessive negative voltage. However, because the anode of the second diode D2 is grounded, D2 conducts, and the voltage is limited to -VF (the voltage drop across the diode at this point), thus effectively protecting operational amplifier U1. Typically, the VF value of a germanium diode is around 0.3V.

[0035] In this embodiment, it is also necessary to consider that since diodes are not completely non-conductive when reverse-biased, they will have a small reverse current. If the reverse currents of the first diode D1 and the second diode D2 are inconsistent, such as the first diode D1 having a large leakage current and the second diode D2 having a small leakage current, the excess leakage current will not have a corresponding path for conduction and will flow into the voltage monitoring circuit, disrupting the normal monitoring of the voltage monitoring circuit and leading to inaccurate data. Therefore, by selecting two diodes with exactly the same reverse current, the reverse current of the first diode D1 will flow directly into the second diode D2 from top to bottom. The reverse current actively flows along this path and will not be diverted to the voltage monitoring circuit. It should be noted that to make the reverse currents of the two diodes as similar as possible, it is mainly necessary to make their voltage difference as close as possible. The closer the voltage difference is, the more consistent the conductivity characteristics are, and the easier it is for the magnitude of the reverse current to tend to be the same; conversely, the larger the voltage difference, the more obvious the difference in reverse current will be. Therefore, by reducing the voltage difference between the two diodes, the reverse currents can be indirectly made closer, thereby avoiding interference with the voltage monitoring circuit.

[0036] It is understandable that by setting the limiting unit, the voltage of the input operational amplifier U1 can be limited to below the safe voltage that the operational amplifier U1 can withstand, while also being able to cope with the short-term high voltage of the low-voltage battery during load dump and the negative voltage during reverse connection.

[0037] This application also provides a vehicle body control module, which includes a voltage monitoring circuit as provided in any of the above embodiments. Specifically, the vehicle body control module is the central nervous system of the automotive electronic system, and its main function is to centrally manage, coordinate, and control the vehicle-related electrical equipment and functions, such as central locking and anti-theft systems, power management and energy-saving control, comfort function control, information collection and status feedback, and vehicle electrical equipment control. The vehicle electrical equipment control includes centralized control of low beam headlights, high beam headlights, turn signals, side marker lights, brake lights, reversing lights, and interior reading lights. It can also control the wiper or washer system; in some models, it can automatically adjust the wiper speed based on rain sensor signals, or receive manual switch signals to control the wiper start / stop and washer spray action; it can also control windows or sunroof, receiving window lift switch signals to control the raising or lowering or closing of the four windows and sunroof, and also has an anti-pinch function. In this application embodiment, a voltage monitoring circuit is set in the vehicle body control module to detect the voltage value of the low-voltage battery, thereby monitoring the battery's charge status. The specific implementation method and technical effects of the voltage monitoring circuit have been described in detail in the above embodiments, and will not be repeated in the embodiments of this application.

[0038] It is worth noting that the body control module is connected to the low-voltage battery via connectors (including electrical connectors and wiring harness connectors) and the wiring harness. The body control module reads the low-voltage battery voltage value every 10ms.

[0039] In summary, the vehicle body control module can replace the traditional distributed relay and fuse control methods, achieving functional integration, intelligence, and energy saving, while improving vehicle safety, comfort, and ease of operation.

[0040] like Figure 3 As shown in the embodiments of this application, a power replenishment system is also provided, including: a low-voltage battery; a DC-DC conversion module connected to the low-voltage battery; a high-voltage battery connected to the DC-DC conversion module; a command transmission module connected to the high-voltage battery; and a body control module as provided in the above embodiments, the body control module being connected to the low-voltage battery and the command transmission module.

[0041] Specifically, the main function of a low-voltage battery is to provide power for the startup and continuous operation of low-voltage devices. During the startup phase, before the vehicle is powered on, the low-voltage battery supplies power to control modules such as the battery management system and the on-board diagnostic (OBD) system, enabling them to enter the initialization state. While the vehicle is in motion, it continuously supplies power to low-voltage electrical appliances such as lights, wipers, central control screen, power seats, door locks, and dashboard. During the engine shutdown or sleep phase, it is used to maintain power supply to low-power devices such as the anti-theft system, remote key receiver module, and clock.

[0042] In this embodiment, the high-voltage battery, also known as a power battery pack, is the power heart of pure electric vehicles and plug-in hybrid vehicles. The high-voltage battery stores high-voltage electrical energy to power the drive motor. Simultaneously, the high-voltage battery also supplies power to high-voltage electrical appliances; some high-voltage equipment in new energy vehicles, such as the vehicle's air conditioning compressor, PTC heater, and fast-charging module, require direct power from the high-voltage terminal of the high-voltage battery.

[0043] In this embodiment, the DC-DC converter module converts the high voltage (e.g., 300V to 800V) of the high-voltage battery into the low voltage (e.g., 12V to 24V) required by the low-voltage system, while simultaneously charging the low-voltage battery to prevent the corresponding functions from becoming unusable due to low-voltage battery depletion.

[0044] In this embodiment, the command sending module, namely the VCU (Vehicle Control Unit), is the brain of the vehicle. The VCU does not directly execute any actions, but instead receives signals from various components, calculates and makes decisions, and then sends commands to the DC-DC converter module, high-voltage battery, drive motor, etc., to coordinate the orderly operation of all vehicle systems.

[0045] In summary, the charging system provided in this application monitors the voltage status of the low-voltage battery through the vehicle control module. When the voltage of the low-voltage battery is lower than a set value, a charging request is sent to the command sending module. Based on the charging request, the command sending module controls the high-voltage battery to supply power to the low-voltage battery. The high-voltage battery converts the high-voltage electricity into low-voltage electricity through a DC-DC conversion circuit to supply power to the low-voltage battery.

[0046] This application also provides a vehicle including the charging system provided in the above embodiments. The specific implementation and technical effects of the charging system have been described in detail in the above embodiments, and will not be repeated here.

[0047] The above description is merely an optional embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A voltage monitoring circuit, characterized in that, include: The voltage divider unit includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is connected to a low-voltage battery, and the other end of the first voltage divider resistor is connected to the second voltage divider resistor. The resistance of the first voltage divider resistor is greater than the resistance of the second voltage divider resistor. A voltage follower unit, wherein the first input terminal of the voltage follower unit is connected between the first voltage divider resistor and the second voltage divider resistor; A limiting unit is connected to the first input terminal of the voltage follower unit; A monitoring chip is connected to the output terminal of the voltage follower unit.

2. The voltage monitoring circuit according to claim 1, characterized in that, The voltage follower unit includes an operational amplifier, which has a first input terminal, a second input terminal, a positive power supply terminal, a negative power supply terminal, and an output terminal. The second input terminal is connected to the output terminal, the positive power supply terminal is connected to a voltage source, and the negative power supply terminal is grounded.

3. The voltage monitoring circuit according to claim 2, characterized in that, The voltage follower unit also includes a feedback resistor connected between the second input terminal and the output terminal of the operational amplifier.

4. The voltage monitoring circuit according to claim 3, characterized in that, It also includes a current-limiting resistor, which is connected to the output of the operational amplifier.

5. The voltage monitoring circuit according to claim 1, characterized in that, The limiting unit includes a first diode and a second diode. The cathode of the first diode is connected to a voltage source, the anode of the first diode is connected to the anode of the second diode, the cathode of the second diode is grounded, and the anode of the first diode is also connected to the first input terminal.

6. The voltage monitoring circuit according to claim 5, characterized in that, The reverse current of the first diode is equal to that of the second diode.

7. The voltage monitoring circuit according to claim 1, characterized in that, The first voltage divider resistor has a first resistance value M1, and the second voltage divider resistor has a second resistance value M2, satisfying: 1 / 6≤M2 / (M1+M2)≤1 / 4.

8. A vehicle body control module, characterized in that, The vehicle body control module includes a voltage monitoring circuit as described in any one of claims 1 to 7.

9. A power replenishment system, characterized in that, include: Low-voltage batteries; A DC-DC converter module, wherein the DC-DC converter module is connected to the low-voltage battery; A high-voltage storage battery, which is connected to the DC-DC conversion module; Command sending module, the command sending module being connected to the high-voltage storage battery; and The body control module as described in claim 8 is connected to the low-voltage battery and the command sending module.

10. A vehicle, characterized in that, Includes the power replenishment system as described in claim 9.

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