Vehicle-mounted high-voltage battery pack combined control system and new-energy vehicle

Abstract

Provided in the present application are a vehicle-mounted high-voltage battery pack combined control system and a new-energy vehicle. A plurality of independent battery packs can be controlled to independently or jointly supply power to a load, wherein when the difference between open-circuit voltages of two battery packs is excessively large, a battery pack having a higher initial voltage is firstly controlled to connect to a power supply, and a current flowing through a current-limiting resistor between the two battery packs is then measured, and when the current is less than a safety value, a battery pack having a lower initial voltage is also connected to a power supply loop, such that a plurality of battery packs supply power in parallel, thereby realizing safe and efficient switching between single-battery-pack power supply and multiple-battery-pack parallel power supply.

Description

On-board high-voltage battery pack combination control system and new energy vehicles

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 2023111947818 filed with the China Patent Office on September 15, 2023, entitled “On-board high-voltage battery pack combination control system and new energy vehicle,” the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the technical field of new energy vehicles, and more specifically, to a vehicle-mounted high-voltage battery pack combination control system and a new energy vehicle. Background Art

[0004] Existing electric trucks consist of two parts: a main vehicle and a trailer. Both the main vehicle and trailer are equipped with large-capacity power batteries, and the power drive unit is located in the main vehicle. The main vehicle also houses an electric drive controller, which controls the front and rear power batteries to power the power drive unit.

[0005] During the driving process, it is necessary to control each power battery to be combined or powered separately. However, due to the different voltages of each power battery, they cannot be connected to the power supply circuit at the same time. Each power battery can only be switched for separate power supply. The existing solution cannot achieve safe switching between separate power supply and parallel power supply.

[0006] Application Contents

[0007] To solve the above problems, an embodiment of the present application provides a vehicle-mounted high-voltage battery pack combination control system, characterized in that the system includes a control module and multiple independent battery packs; the positive pole of the first battery pack is connected to the load through a first positive switch, and the negative pole is connected to the load through a first negative switch; the positive pole of the second battery pack is connected to the load through a second positive switch and a second control switch, and the negative pole is connected to the load through a second negative switch; a second current limiting resistor is connected in series with the second current limiting resistor switch and is connected in parallel with the second control switch; a capacitor is connected in parallel with the load; the control module is configured to: when it is detected that the open-circuit voltage of the first battery pack is greater than the open-circuit voltage of the second battery pack, and the voltage difference is greater than the safety voltage difference threshold, control the first negative switch, The first positive switch is closed; and after controlling the second positive switch, the second negative switch, and the second current-limiting resistor switch to be closed and the second control switch to be disconnected, the current flowing through the second current-limiting resistor is obtained. If the current is less than the safe parallel current threshold, the second control switch is controlled to be closed; if the current is greater than or equal to the safe parallel current threshold, the second positive switch, the second negative switch, or the second current-limiting resistor switch is controlled to be disconnected; when it is detected that the voltage difference between the open-circuit voltage of the first battery pack and the open-circuit voltage of the second battery pack is less than the safe voltage difference threshold, the first negative switch and the first positive switch are controlled to be closed; and the second negative switch, the second control switch, and the second positive switch are controlled to be closed.

[0008] Optionally, the battery further includes a first control switch and a first current-limiting resistor; the first control switch is connected between the first positive switch and the load; the first current-limiting resistor is connected in series with the first current-limiting resistor switch and then in parallel with the first control switch; the control module is configured to: upon detecting that the open-circuit voltage of the second battery pack is greater than the open-circuit voltage of the first battery pack and the voltage difference is greater than a safety voltage difference threshold, control the second negative switch, the second control switch, and the second positive switch to be closed; and control the first positive switch, the first negative switch, and the first current-limiting resistor to be closed, and after the first control switch is opened, obtain the current flowing through the first current-limiting resistor, and if the current is less than the safety parallel current threshold, control the first control switch to be closed; if the current is greater than or equal to the safety parallel current threshold, control the first positive switch, the first negative switch, or the first current-limiting resistor to be opened; upon detecting that the voltage difference between the open-circuit voltage of the first battery pack and the open-circuit voltage of the second battery pack is less than the safety voltage difference threshold, control the second negative switch, the second control switch, and the second positive switch to be closed, and control the first negative switch, the first control switch, and the first positive switch to be closed.

[0009] Optionally, it also includes a first pre-charging resistor, a first pre-charging resistor switch, a second pre-charging resistor and a second pre-charging resistor switch; the first pre-charging resistor is connected in series with the first pre-charging resistor switch and then connected in parallel with the first positive switch; the second pre-charging resistor is connected in series with the second pre-charging resistor switch and then connected in parallel with the second positive switch; the control module is configured to: before the first battery pack and the second battery pack are connected to the capacitor, control the first pre-charging resistor switch and the second pre-charging resistor switch to be closed, and the first positive switch and the second positive switch to be disconnected for pre-charging; after the pre-charging is completed, control the first positive switch and the second positive switch to be closed.

[0010] Optionally, a third control switch is further included, and the third control switch is connected between the second cathode switch and the load.

[0011] Optionally, a DC-DC converter is further included, and the DC-DC converter is connected between the load and the second control switch and the second cathode switch.

[0012] Optionally, a bypass switch connected in parallel with the DC-DC converter is further included.

[0013] Optionally, the device further includes a voltage detection element configured to detect the open circuit voltage of the first battery pack and the second battery pack.

[0014] Optionally, it further includes a current detection element configured to detect the current flowing through the first current limiting resistor and the second current limiting resistor.

[0015] An embodiment of the present application provides a new energy vehicle, comprising any of the above-mentioned on-board high-voltage battery pack combined control systems.

[0016] The on-board high-voltage battery pack combination control system and new energy vehicle of the embodiments of the present application can control multiple independent battery packs to supply power to the load individually or collectively. When the open-circuit voltage difference between the two battery packs is too large, the battery pack with the higher initial voltage is first controlled to be pre-charged and then connected to the power supply, and then the current flowing through the current-limiting resistor between the two battery packs is detected. When the current is less than the safety value, the battery pack with the lower initial voltage is also connected to the power supply circuit, and multiple battery packs are powered in parallel, thereby realizing safe and efficient switching between single battery pack power supply and multiple battery packs in parallel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application 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 merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0018] FIG1 is a schematic structural diagram of a truck according to an embodiment of the present application;

[0019] FIG2 is a circuit diagram of a vehicle-mounted high-voltage battery pack combined control system according to an embodiment of the present application;

[0020] FIG3 is a circuit diagram of another vehicle-mounted high-voltage battery pack combination control system according to an embodiment of the present application;

[0021] FIG4 is a circuit diagram of another vehicle-mounted high-voltage battery pack combination control system in an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned objectives, features and advantages of the present application more clearly understood, the following detailed description of the specific embodiments of the present application is given in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0023] In the embodiment of the present application, a method for solving the problem of combining two or more independent high-voltage battery packs on a vehicle is designed. The main application scenario of the above method is that both the main vehicle and the trailer of the truck are equipped with large-capacity power batteries, and the power drive unit is located in the main vehicle. Figure 1 shows a schematic structural diagram of the truck. In Figure 1, two independent power batteries are used as an example. The main vehicle 1 is provided with a battery pack 10 and a power drive unit 3, and the trailer 2 is provided with a battery pack 20.

[0024] An embodiment of the present application provides a vehicle-mounted high-voltage battery pack combination control system, which includes a control module and multiple independent battery packs.

[0025] FIG2 shows a circuit diagram of a vehicle-mounted high-voltage battery pack combined control system, and takes the battery packs 10 and 20 as an example for explanation.

[0026] The positive electrode of the first battery pack 10 is connected to the load through the first positive switch K1, and the negative electrode is connected to the load through the first negative switch K2;

[0027] The positive electrode of the second battery pack 20 is connected to the load through the second positive switch K4 and the second control switch K7, and the negative electrode is connected to the load through the second negative switch K5; the second current limiting resistor R3 is connected in series with the second current limiting resistor switch K9 and then in parallel with the second control switch K7;

[0028] Capacitor C is connected in parallel with the load;

[0029] The above-mentioned control module is configured to: when it is detected that the open-circuit voltage of the first battery pack is greater than the open-circuit voltage of the second battery pack, and the voltage difference is greater than the safety voltage difference threshold, control the first negative switch and the first positive switch to be closed; and control the second positive switch, the second negative switch, and the second current-limiting resistor switch to be closed. After the second control switch is disconnected, the current flowing through the second current-limiting resistor is obtained. If the current is less than the safety parallel current threshold, the second control switch is controlled to be closed. If the current is greater than or equal to the safety parallel current threshold, the second positive switch, the second negative switch or the second current-limiting resistor switch is controlled to be disconnected.

[0030] Before the vehicle's high-voltage power is applied, battery packs 10 and 20 are disconnected from the high-voltage system, and the open-circuit voltages of the two battery packs can be measured. If the difference between the open-circuit voltages of the two battery packs exceeds the safety voltage differential threshold, and the open-circuit voltage of the first battery pack is greater than that of the second battery pack, the first battery pack, with its higher voltage, is prioritized to supply power to the load.

[0031] Then, by controlling the second current limiting resistor to connect the second battery pack to the first battery pack, the current flowing through the second current limiting resistor can be measured in real time to determine the voltage difference between the two battery packs. Taking into account that the voltage of the first battery pack continues to drop as the power supply progresses, the current flowing through the second current limiting resistor can be continuously obtained. If the current is less than the safe parallel current threshold, the second control switch is controlled to close so that the two battery packs are powered in parallel. In this case, the voltage difference between the two battery packs is small enough that the second battery pack can be fully incorporated into the high-voltage system, so the second current limiting resistor is short-circuited to incorporate the second battery pack into the high-voltage system. If the current is greater than or equal to the safe parallel current threshold, the second positive switch, the second negative switch or the second current limiting resistor switch is controlled to disconnect, keeping the first battery pack powered alone.

[0032] It should be noted that the above control process of controlling the second battery pack to be connected to the first battery pack and detecting the current flowing through the second current limiting resistor is executed cyclically until the current is less than the safe parallel current threshold and the two battery packs reach a parallel power supply state.

[0033] When it is detected that the voltage difference between the open-circuit voltage of the first battery pack and the open-circuit voltage of the second battery pack is less than the safety voltage difference threshold, the first negative switch and the first positive switch are controlled to be closed; and the second negative switch, the second control switch, and the second positive switch are controlled to be closed.

[0034] If the difference between the open-circuit voltages of the two battery packs is less than the safety voltage difference threshold, the first battery pack and the second battery pack can be connected to the high-voltage system simultaneously or successively to jointly supply power to the load.

[0035] The above-mentioned vehicle-mounted high-voltage battery pack combination control system provided in the embodiment of the present application can control multiple independent battery packs to supply power to the load individually or collectively. When the open-circuit voltage difference between the two battery packs is too large, the battery pack with a higher initial voltage is first controlled to be connected to the power supply, and then the current flowing through the current-limiting resistor between the two battery packs is detected. When the current is less than the safety value, the battery pack with a lower initial voltage is also connected to the power supply circuit, and multiple battery packs are supplied in parallel, thereby realizing safe and efficient switching between single battery pack power supply and multiple battery packs in parallel.

[0036] Furthermore, the control system further includes a first pre-filling resistor and a first pre-filling resistor switch. As shown in FIG2 , the first pre-filling resistor R1 is connected in series with the first pre-filling resistor switch K3 and then connected in parallel with the first positive switch K1.

[0037] The control module is configured to: before the first battery pack is connected to the capacitor, control the first pre-charge resistor switch to close and the first positive switch to open to perform pre-charging; and control the first positive switch to close after pre-charging is completed. For example, the first battery pack first connects the first pre-charge resistor to the circuit to pre-charge the capacitor based on the pre-charge resistor, and then short-circuit the first pre-charge resistor after pre-charging is completed to directly supply power to the load.

[0038] FIG2 shows a power battery 10 and a battery 20 , K1 and K2 are the positive and negative contactors of the battery 10 , R1 is a pre-charge resistor, and K3 is a pre-charge resistor switch;

[0039] K4 and K5 are the positive and negative contactors of battery 20 respectively, R2 is the pre-charge resistor, and K6 is the pre-charge resistor switch; K7 and K8 are the positive and negative contactors controlled by the two battery combinations respectively, R3 is the pre-charge resistor, and K9 is the pre-charge resistor switch; the vehicle can measure the voltage U1 and U2 across battery 10 and battery 20, and the current I flowing through resistors R1, R2, and R3 R1 , I R2 , I R3 Before the vehicle high voltage is powered on, battery 10 and battery 20 are not connected to the high voltage system. At this time, the open circuit voltage of battery 10 and battery 20 can be measured, that is, the voltage U1 inside the contactor of K1 and K2 is open, and the voltage U2 inside the contactor of K4 and K5 is open.

[0040] The load is connected in parallel with capacitor C, effectively protecting the battery from sudden, high-current discharges. For example, when a vehicle starts, a large starting current is required. The battery and capacitor simultaneously power the motor, and the capacitor can instantly provide a strong current to the motor, providing some protection for the battery. The capacitor acts as an energy storage and voltage regulator, ensuring smooth motor operation, increasing starting torque, assisting in motor startup, protecting the circuit, and stabilizing voltage.

[0041] If the open circuit voltage U1 of the two batteries开路 and U2 开路 The difference is much greater than the safety voltage difference U of the batteries connected in parallel 安全并联 (For example, 20 volts), the vehicle will first close the contactor of the battery pack with higher voltage to connect to the circuit: for example, U1 开路 -U2 开路 >20V, close contactors K2 and K3, and after the pre-charge is completed (determined based on the current flowing through resistor R1), close K1 to short-circuit resistor R1, so that battery 1 is connected to the high-voltage system. Then close K5, K8, K4, and K9, so that battery 20 is also connected to the high-voltage system through the pre-charge resistor R3. At this time, the current will flow from battery 10 to battery 20 through R3. The current flowing through R3 is detected, and the voltage difference between the two batteries is judged based on the current. When it is less than the safe value, control battery 2 to connect to the circuit (for example, close K4, K7, K5, and K8). If it is judged that the voltage difference between the two batteries is greater than the safe value, one or more of K5, K8, and K4 are disconnected, and battery 1 is kept powered alone. After battery 1 has been powered alone for a certain period of time, the above process of closing K5, K8, K4, and K9, detecting the current flowing through R3, and subsequently judging the pressure difference is executed. Repeat the above process until the pressure difference is less than the safe value, and control the two batteries to power in parallel.

[0042] The above-mentioned pre-charge resistor is generally between 60 and 100 ohms. The value of the pre-charge resistor used by the battery pack is determined by the capacity of the motor controller capacitor. The larger the capacitor, the larger the resistance value used, and vice versa.

[0043] The current limiting resistor R3 is usually designed to be relatively large, such as 200 ohms, so the current is relatively small, such as less than 1 ampere. As the high-voltage system power is used, the voltage difference between battery 10 and battery 20 will gradually decrease, that is, the current flowing through R3 will gradually decrease until it is less than the voltage difference current I of the parallel batteries. 安全并联 (For example, 0.1A), at this time, the contactor K7 is closed, so that the battery 2 is also fully integrated into the high voltage system.

[0044] If the open circuit voltage U1 of the two batteries 开路 and U2 开路 If the difference is less than the safety voltage difference Usafe parallel connection of batteries (for example, 20 volts), the vehicle will connect one of the batteries to the high-voltage system first, and the other battery will be connected to the high-voltage system after a short pre-charge.

[0045] FIG3 shows a circuit diagram of another vehicle-mounted high-voltage battery pack control system. Based on the circuit shown in FIG2 , a first control switch K10 and a first current-limiting resistor R4 are added.

[0046] Specifically, one end of the first control switch K10 is connected to the first positive switch K1 , and the other end of the first control switch K10 is connected to the load; the first current limiting resistor R4 is connected in series with the first current limiting resistor switch K11 and then connected in parallel with the first control switch K10 .

[0047] The above-mentioned control module is configured to: when it is detected that the open-circuit voltage of the second battery pack is greater than the open-circuit voltage of the first battery pack, and the voltage difference is greater than the safety voltage difference threshold, control the second negative switch, the second control switch, and the second positive switch to be closed; and control the first positive switch, the first negative switch, and the first current-limiting resistor switch to be closed. After the first control switch is disconnected, the current flowing through the first current-limiting resistor is obtained. If the current is less than the safety parallel current threshold, the first control switch is controlled to be closed. If the current is greater than or equal to the safety parallel current threshold, the first positive switch, the first negative switch or the first current-limiting resistor switch is controlled to be disconnected.

[0048] If the difference between the open circuit voltages of the two battery packs is greater than the safety voltage difference threshold, and the open circuit voltage of the second battery pack is greater than the open circuit voltage of the first battery pack, the second battery pack is preferentially controlled to supply power to the load.

[0049] Then, by controlling the first current limiting resistor to connect the second battery pack to the first battery pack, the current flowing through the first current limiting resistor can be measured in real time to determine the voltage difference between the two battery packs. Taking into account that the voltage of the second battery pack continues to drop as the power supply progresses, the current flowing through the first current limiting resistor can be continuously obtained. If the current is less than the safe parallel current threshold, the first control switch is controlled to close so that the two battery packs are powered in parallel. In this case, the voltage difference between the two battery packs is small enough that the first battery pack can be fully incorporated into the high-voltage system, so the first current limiting resistor is short-circuited to incorporate the first battery pack into the high-voltage system. If the current is greater than or equal to the safe parallel current threshold, the first positive switch, the first negative switch or the first current limiting resistor switch is controlled to disconnect, keeping the second battery pack powered alone.

[0050] The control process of controlling the second battery pack to be connected to the first battery pack and detecting the current flowing through the first current limiting resistor is executed cyclically until the current is less than the safe parallel current threshold and the two battery packs reach a parallel power supply state.

[0051] The above-mentioned control module is configured to: when it is detected that the voltage difference between the open-circuit voltage of the first battery pack and the open-circuit voltage of the second battery pack is less than the safety voltage difference threshold, control the second negative pole switch, the second control switch, and the second positive pole switch to close, and control the first negative pole switch and the first control switch to close, and control the first positive pole switch to close after the pre-charging is completed.

[0052] If the difference between the open-circuit voltages of the two battery packs is less than the safety voltage difference threshold, the first battery pack and the second battery pack can be connected to the high-voltage system simultaneously or successively to jointly supply power to the load.

[0053] Furthermore, the control system further includes a second pre-filling resistor and a second pre-filling resistor switch. As shown in FIG3 , the second pre-filling resistor R2 is connected in series with the second pre-filling resistor switch K6 and then connected in parallel with the second positive switch K4.

[0054] The control module is configured to: before the second battery pack is connected to the capacitor, control the second pre-charge resistor switch to close and the second positive switch to open to perform pre-charging; and control the second positive switch to close after pre-charging is completed. For example, the second battery pack first connects the second pre-charge resistor to the circuit to pre-charge the capacitor based on the pre-charge resistor, and then short-circuit the second pre-charge resistor after pre-charging is completed to directly supply power to the load.

[0055] As shown in FIG2-3 , the control system further includes a third control switch K8 , which is connected between the second cathode switch and the load.

[0056] Figure 4 shows a circuit diagram of another vehicle-mounted high-voltage battery pack control system. Based on the circuit shown in Figure 2, a DC-DC converter is added. This DC-DC converter is connected between the load and the second control switch and the second cathode switch. Based on this, this embodiment can boost or buck the voltage of the two battery packs to balance the voltages of the two battery packs.

[0057] Furthermore, the above circuit also includes a bypass switch K12 connected in parallel with the DC-DC converter.

[0058] Optionally, the control system further includes a voltage detection element configured to detect the open circuit voltage of the first battery pack and the second battery pack.

[0059] Optionally, the control system further includes a current detection element configured to detect the current flowing through the first current limiting resistor and the second current limiting resistor.

[0060] An embodiment of the present application provides a new energy vehicle, including the above-mentioned vehicle-mounted high-voltage battery pack combined control system.

[0061] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims.

[0062] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0063] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from the other embodiments. Similar or identical parts between the various embodiments can be referred to in detail. Regarding the sports platform acceleration safety protection device disclosed in the embodiment, since it corresponds to the sports platform acceleration safety protection method disclosed in the above embodiment, the description is relatively simple, and relevant parts can be referred to the method description.

[0064] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein. Industrial Applicability

[0065] The on-board high-voltage battery pack combination control system and new energy vehicle provided in the embodiments of the present application can control multiple independent battery packs to supply power to the load individually or collectively, realize safe and efficient switching between single battery pack power supply and multiple battery packs in parallel, and have significant economic benefits.

Claims

1. A vehicle-mounted high-voltage battery pack combined control system, characterized in that: The system includes a control module and a plurality of independent battery packs; The positive electrode of the first battery pack is connected to the load through a first positive switch, and the negative electrode is connected to the load through a first negative switch; The positive electrode of the second battery pack is connected to the load through the second positive electrode switch and the second control switch, and the negative electrode is connected to the load through the second negative electrode switch; the second current limiting resistor is connected in series with the second current limiting resistor switch and then connected in parallel with the second control switch; A capacitor is connected in parallel with the load; The control module is configured to: when it is detected that the open circuit voltage of the first battery pack is greater than the open circuit voltage of the second battery pack, and the voltage difference is greater than a safety voltage difference threshold, control the first negative switch and the first positive switch to be closed; and after controlling the second positive switch, the second negative switch, and the second current limiting resistor switch to be closed and the second control switch to be opened, obtain the current flowing through the second current limiting resistor, and if the current is less than a safety parallel current threshold, control the second control switch to be closed, and if the current is greater than or equal to the safety parallel current threshold, control the second positive switch, the second negative switch, or the second current limiting resistor switch to be opened; When it is detected that the voltage difference between the open-circuit voltage of the first battery pack and the open-circuit voltage of the second battery pack is less than a safety voltage difference threshold, the first negative switch and the first positive switch are controlled to be closed; and the second negative switch, the second control switch, and the second positive switch are controlled to be closed.

2. The vehicle-mounted high-voltage battery combination control system according to claim 1, characterized in that: Also includes a first control switch and a first current limiting resistor; The first control switch is connected between the first positive switch and the load; A first current limiting resistor is connected in series with a first current limiting resistor switch and then connected in parallel with the first control switch; The control module is configured to: when it is detected that the open-circuit voltage of the second battery pack is greater than the open-circuit voltage of the first battery pack, and the voltage difference is greater than a safety voltage difference threshold, control the second negative switch, the second control switch, and the second positive switch to be closed; and control the first positive switch, the first negative switch, and the first current-limiting resistor switch to be closed, and after the first control switch is opened, obtain the current flowing through the first current-limiting resistor, and if the current is less than the safety parallel current threshold, control the first control switch to be closed, and if the current is less than the safety parallel current threshold, control the first control switch to be closed. If the current is greater than or equal to the safety parallel current threshold, the first positive switch, the first negative switch or the first current limiting resistor switch is controlled to be disconnected; When it is detected that the voltage difference between the open-circuit voltage of the first battery group and the open-circuit voltage of the second battery group is less than the safety voltage difference threshold, the second negative switch, the second control switch, and the second positive switch are controlled to be closed, and the first negative switch, the first control switch, and the first positive switch are controlled to be closed.

3. The vehicle-mounted high-voltage battery combination control system according to claim 2, characterized in that: It also includes a first pre-charging resistor, a first pre-charging resistor switch, a second pre-charging resistor and a second pre-charging resistor switch; The first pre-filling resistor is connected in series with the first pre-filling resistor switch and then connected in parallel with the first positive switch; the second pre-filling resistor is connected in series with the second pre-filling resistor switch and then connected in parallel with the second positive switch; The control module is configured to: before the first battery group and the second battery group are connected to the capacitor, control the first pre-charging resistance switch and the second pre-charging resistance switch to be closed, and the first positive switch and the second positive switch to be opened for pre-charging; after the pre-charging is completed, control the first positive switch and the second positive switch to be closed.

4. The vehicle-mounted high-voltage battery combination control system according to claim 3, characterized in that: The resistance values ​​of the first pre-charging resistor and the second pre-charging resistor are determined according to the capacity of the motor controller capacitor.

5. The vehicle-mounted high-voltage battery combination control system according to claim 3, characterized in that: The resistance of the first pre-charging resistor and the second pre-charging resistor is 60 to 100 ohms.

6. The vehicle-mounted high-voltage battery combination control system according to claim 3, characterized in that: The resistance of the first current limiting resistor and the second current limiting resistor is greater than or equal to 200 ohms.

7. The vehicle-mounted high-voltage battery combination control system according to any one of claims 1 to 6, characterized in that: The device further includes a third control switch connected between the second cathode switch and a load.

8. The vehicle-mounted high-voltage battery combination control system according to any one of claims 1 to 7, characterized in that: The system further includes a DC-DC converter connected between the load and the second control switch and the second cathode switch.

9. The vehicle-mounted high-voltage battery combination control system according to claim 8, characterized in that: Also included is a bypass switch connected in parallel with the DC-DC converter.

10. The vehicle-mounted high-voltage battery combination control system according to claim 1 or 2, characterized in that: The battery pack further includes a voltage detection element configured to detect an open circuit voltage of the first battery pack and the second battery pack.

11. The vehicle-mounted high-voltage battery combination control system according to claim 10, characterized in that: Before the vehicle is powered on at high voltage, the first battery pack and the second battery pack are not connected to the high voltage system, and the voltage detection element is configured to measure the open circuit voltage of the first battery pack and the second battery pack.

12. The vehicle-mounted high-voltage battery combination control system according to any one of claims 2 to 11, characterized in that: The device further includes a current detection element configured to detect a current flowing through the first current limiting resistor and the second current limiting resistor.

13. The vehicle-mounted high-voltage battery combination control system according to any one of claims 1 to 12, characterized in that: The safety voltage difference threshold is greater than or equal to 20 volts.

14. The vehicle-mounted high-voltage battery combination control system according to any one of claims 1 to 12, characterized in that: The safety parallel current threshold is less than or equal to 0.1A.

15. A new energy vehicle, characterized in that: It includes the vehicle-mounted high-voltage battery pack combined control system as described in any one of claims 1-14.

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