Vehicle-mounted power supply device, vehicle, vehicle power failure starting system and method

Abstract

The application relates to a vehicle-mounted power supply device, a vehicle, a vehicle power shortage starting system and method, which comprises a storage battery, a vehicle controller electrically connected with the storage battery, used for detecting the voltage value of the storage battery, judging whether the storage battery is in a power shortage state according to the detected voltage value, a vehicle interface arranged in the vehicle to realize the electrical connection between a vehicle-mounted charger and an external charging device, an input end of the vehicle-mounted charger connected with the vehicle interface, a DC converter with an input end connected with the output end of the vehicle-mounted charger and an output end connected with the storage battery, and the vehicle controller allowing the external charging device to charge the storage battery through the vehicle-mounted charger and the DC converter when the external charging device is connected with the vehicle and the storage battery is in the power shortage state. The application solves the problem that the vehicle cannot be started due to the power shortage of the storage battery.

Description

Technical Field

[0001] This invention relates to the field of automotive battery management technology, specifically to an on-board power supply device, a vehicle, a vehicle low-battery start-up system, and a method. Background Technology

[0002] With the rapid development of the automotive industry, especially the continuous breakthroughs in electric vehicle technology, the level of vehicle intelligence has significantly improved. This progress relies heavily on the application of numerous low-voltage sensors and controllers, which work together to achieve intelligent management and control of the vehicle. However, the normal operation of these low-voltage components is highly dependent on a stable power supply, typically provided by lead-acid batteries.

[0003] During the normal operation of an electric vehicle, the lead-acid battery not only provides power for starting the vehicle but also ensures that all components of the system can function properly before the vehicle receives high-voltage power. However, in actual use, due to various reasons, such as low-voltage electrical appliances not being turned off, the controller not entering sleep mode, or the vehicle being parked for a long time, the lead-acid battery may gradually lose power. When the lead-acid battery voltage is too low, it will not be able to provide enough power to the vehicle system, thus preventing the vehicle from starting normally and causing great inconvenience to the owner.

[0004] To address this issue, the industry has proposed several solutions. For example, one solution provides a method to power the vehicle controller using the auxiliary power supply of a DC charging station. However, this method is limited by the installation location of the DC charging station and the vehicle's parking time, as situations where parking a vehicle at a DC charging station results in a relatively low discharge of the lead-acid battery are less common.

[0005] Another approach proposes a method that provides AC power to the vehicle by closing a switch via a specific signal when the vehicle detects a low lead-acid battery voltage. However, this method relies on lead-acid battery voltage detection and controller operation at the vehicle end. If the lead-acid battery voltage has dropped below the operating voltage of the vehicle controller, the function will not be activated, thus limiting its practical application.

[0006] In addition, another proposed solution is an electric vehicle battery recovery system based on AC charging stations. This system wakes up the integrated power battery unit by the voltage of the AC charging gun, thereby obtaining power from the AC charging station. However, this solution also has limitations: when the lead-acid battery voltage is too low to support the normal operation of the controller, voltage detection and switching control cannot be achieved, which may result in the vehicle failing to start.

[0007] In summary, existing technologies still have significant shortcomings in solving the problem of electric vehicles failing to start due to depleted lead-acid batteries. On the one hand, while DC charging can provide external power, its practical application is limited by space constraints and vehicle parking time. On the other hand, the vehicle controller operates at a voltage of around 9-16V. When the lead-acid battery is completely depleted or even close to 0V, the vehicle controller cannot function properly, failing to detect depleted lead-acid batteries at the vehicle end and control the S2 switch closure, thus preventing AC charging stations from providing power.

[0008] Therefore, it is necessary to develop a new vehicle-mounted power supply device, vehicle, vehicle low-power start-up system and method. Summary of the Invention

[0009] The purpose of this invention is to provide an on-board power supply device, a vehicle, a vehicle starting system and method for low battery, which can solve the problem of vehicles being unable to start due to low battery power.

[0010] In a first aspect, the vehicle-mounted power supply device of the present invention includes:

[0011] Storage battery;

[0012] The vehicle controller is electrically connected to the battery and is used to detect the battery voltage and determine whether the battery is in a low-charge state based on the detected voltage.

[0013] The vehicle interface is used to match the charging gun of an external charging device to achieve electrical connection between the on-board charger and the external charging device.

[0014] An on-board charger, whose input end is connected to the vehicle interface, is used to convert AC power provided by external charging equipment into DC power.

[0015] A DC-DC converter, whose input is connected to the output of the on-board charger and whose output is connected to the battery, is used to convert the DC power output by the on-board charger into voltage and current suitable for charging the battery.

[0016] The vehicle controller detects that the external charging device is connected to the vehicle interface and the battery is in a depleted state, and allows the external charging device to charge the battery through the on-board charger and DC-DC converter.

[0017] Optionally, the vehicle controller also includes a PWM wave generation unit. When a low battery is detected, the PWM wave generation unit sends a preset PWM signal to the external charging device via the CC line to indicate the low battery status. This signal transmission method is efficient and stable, quickly and accurately conveying the low battery status to the external charging device, thereby triggering the external charging device's response mechanism to supply power or charge the vehicle.

[0018] Optionally, the vehicle controller is connected to the CP line via switch K3. When the external charging device is detected to be connected to the vehicle interface and switch K3 is closed, the external charging device is allowed to directly power the vehicle controller through the CP line. By setting switch K3 in the CP line, the vehicle controller can more flexibly control the on / off state of the CP line. When the switching power supply of the external charging device is needed to power the vehicle controller, switch K3 is closed; when the switching power supply of the external charging device is not needed to power the vehicle, switch K3 can be opened.

[0019] Secondly, a vehicle comprising:

[0020] Vehicle body;

[0021] The vehicle-mounted power supply device as described in this invention is mounted on the vehicle body.

[0022] Thirdly, the vehicle low-battery start system of the present invention includes:

[0023] The vehicle as described in this invention;

[0024] An external charging device includes a charging gun and a device controller, wherein the charging gun is matched with the vehicle interface of the vehicle for connection, and the device controller is connected to the CC terminal of the charging gun.

[0025] When the vehicle is connected to the external charging device, the vehicle's on-board power supply device sends a low-power status signal to the external charging device via the CC line when it detects that the battery is in a low-power state. After the device controller detects the low-power status signal, it supplies power to the vehicle and charges the battery through the external charging device.

[0026] Optionally, the external charging device further includes a switching power supply, which is connected to the CP terminal of the charging gun via switch K2. After the charging gun is connected to the vehicle interface and started, the switching power supply provides power to the vehicle controller in the on-board power supply device through the CP line. After the charging gun is connected to the vehicle interface and the charging process begins, the switching power supply of the external charging device can provide the necessary power to the vehicle controller through the CP line. This design effectively solves the problem that the vehicle controller cannot operate due to lack of power supply when the battery is completely depleted, or even when the voltage is close to 0V. In this situation, the traditional battery depletion detection mechanism and the closing control of switch S2 (see GB / T 18487.1-2023) cannot be implemented, resulting in the AC charging pile being unable to provide the required power to the vehicle. By introducing a switching power supply and providing power to the vehicle controller through the CP line, this invention ensures that the vehicle controller can operate normally even when the battery is completely depleted, thus smoothly realizing battery depletion detection, switch control, and power supply from the AC charging pile.

[0027] Optionally, the external charging device is an AC charging pile. This is suitable for application scenarios where the ratio of AC charging piles to parking spaces for electric vehicles is high and the battery voltage is low when vehicles are parked for extended periods.

[0028] Fourthly, the vehicle low-battery start method of the present invention employs the vehicle low-battery start system as described in the present invention, and the method includes the following steps:

[0029] The external charging device is connected to the vehicle via a charging gun.

[0030] The vehicle controller detects the battery voltage to determine if the battery is low on charge.

[0031] If the battery voltage is less than or equal to the first preset threshold, it indicates that the battery is low on power, and the vehicle controller sends a low-power status signal to the external charging device.

[0032] Upon receiving the low-power signal, the external charging device provides power to the vehicle.

[0033] The on-board charger and DC-DC converter convert the electricity output from the external charging equipment into low-voltage DC power to power the vehicle's low-voltage system and charge the battery.

[0034] Fifthly, the present invention provides a method for starting a vehicle when its battery is low, employing a vehicle starting system as described in the present invention, the method comprising the following steps:

[0035] After the external charging device is connected to the vehicle via the charging gun, the switching power supply of the external charging device supplies power to the vehicle controller in the on-board power supply unit through the CP line.

[0036] The vehicle controller detects the battery voltage to determine if the battery is low on charge.

[0037] If the battery voltage is less than or equal to the first preset threshold, it indicates that the battery is low on power, and the vehicle controller sends a low-power status signal to the external charging device.

[0038] Upon receiving the low-power signal, the external charging device provides power to the vehicle.

[0039] The on-board charger and DC-DC converter convert the electricity output from the external charging equipment into low-voltage DC power to power the vehicle's low-voltage system and charge the battery.

[0040] Optionally, it also includes:

[0041] When the vehicle controller detects that the battery voltage is greater than the second preset threshold, the vehicle controller wakes up the vehicle's low-voltage system and sends a battery charging mode signal to determine whether the high-voltage power-on conditions are met. If they are met, the high-voltage power-on is completed. After the high-voltage power-on is completed, the circuit between the control power supply and the vehicle controller is disconnected.

[0042] Determine if the power battery needs charging;

[0043] If the power battery has no charging requirement and the battery charging mode sent by the vehicle controller is valid, the vehicle maintains a high-voltage energized state, and the duration of this high-voltage energized state is determined experimentally based on the battery's depleted voltage value. This step helps to promptly wake up the vehicle's low-voltage system and initiate the battery charging mode when the battery voltage recovers to a certain level. This not only ensures the normal operation of the vehicle's low-voltage system with sufficient power supply but also allows for flexible adjustment of the charging strategy based on the battery's depletion level, thereby improving charging efficiency and battery lifespan. In battery charging mode, the charging strategy can be flexibly adjusted based on the actual situation to determine if the power battery has a charging requirement. If the power battery has no charging requirement, the vehicle can maintain a high-voltage energized state to supply power to the vehicle's low-voltage system; if the power battery has a charging requirement, it can be charged first. This flexible charging strategy helps improve charging efficiency and energy utilization.

[0044] The beneficial effects of this invention are as follows: The vehicle power supply device, vehicle low-battery start system, and method described in this invention include a battery, a vehicle controller, an on-board charger, a DC-DC converter, and a vehicle interface. The vehicle controller intelligently detects the battery voltage, determines the low-battery state, and connects to an external charging device via the on-board charger and DC-DC converter to convert AC power to DC power suitable for battery charging. When the battery is low-battery but meets charging conditions, the vehicle controller allows the external charging device to charge the battery, effectively solving the problem of the vehicle failing to start due to a low-battery battery. Furthermore, the external charging device includes a switching power supply. After the charging gun is connected to the vehicle, the switching power supply can directly power the vehicle controller, thus solving the problem that the vehicle controller cannot operate due to lack of power supply when the battery is completely depleted or even close to 0V. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the vehicle low-battery start-up system described in the embodiments of this application;

[0046] Figure 2 This is a flowchart of the vehicle low-battery start-up method described in Embodiment 1 of this application;

[0047] Figure 3 This is a flowchart of the vehicle low-battery start-up method described in Embodiment 2 of this application;

[0048] Figure 4 This is a detailed flowchart of the vehicle low-battery start-up method described in the embodiments of this application. Detailed Implementation

[0049] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0050] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0051] Example 1

[0052] like Figure 1As shown, an on-board power supply device includes a battery, a vehicle controller, an on-board charger, a DC-DC converter, and a vehicle interface. The vehicle controller is electrically connected to the battery and is used to detect the battery voltage and determine whether the battery is in a low-charge state based on the detected voltage. The vehicle interface is used to match the charging gun of an external charging device to achieve electrical connection between the on-board charger and the external charging device. The input terminal of the on-board charger is connected to the vehicle interface and is used to convert the AC power provided by the external charging device into DC power. The input terminal of the DC-DC converter is connected to the output terminal of the on-board charger, and the output terminal of the DC-DC converter is connected to the battery, used to convert the DC power output by the on-board charger into a voltage and current suitable for charging the battery. When the vehicle controller detects that the external charging device is connected to the vehicle interface and the battery is in a low-charge state, it allows the external charging device to charge the battery through the on-board charger and the DC-DC converter.

[0053] like Figure 1 As shown, in one possible embodiment, an on-board power supply device further includes a switch S2, a resistor R2, and a resistor R3. One end of the switch S2 is connected to the PE line, and the other end of the switch S2 is connected to the CP terminal of the vehicle interface via the resistor R2 and the diode D1. One end of the resistor R3 is connected to the PE line, and the other end of the resistor R3 is connected to the connection point of the negative terminals of the resistor R2 and the diode D1.

[0054] like Figure 1 As shown, in one possible embodiment, the vehicle controller is connected to the CC terminal of the vehicle interface, and the connection point between the vehicle controller and the CC terminal of the vehicle interface is set as detection point three.

[0055] like Figure 1 As shown, in one possible embodiment, the vehicle controller is connected to the CP line via switch K3. When an external charging device is detected connected to the vehicle and switch K3 is closed, the external charging device is allowed to directly power the vehicle controller through the CP line. By setting switch K3 in the CP line, the vehicle controller can more flexibly control the on / off state of the CP line. When the switching power supply of the external charging device is needed to power the vehicle controller, switch K3 is closed; when the switching power supply of the external charging device is not needed to power the vehicle, switch K3 can be opened. The connection point of switch K3 and diode D1 is set as detection point two.

[0056] like Figure 1As shown, in one possible embodiment, the vehicle controller further includes a PWM wave generation unit. When a low battery is detected, the PWM wave generation unit sends a preset PWM signal to the external charging device via the CC line to indicate the low battery status. This signal transmission method is efficient and stable, quickly and accurately conveying the low battery status to the external charging device, thereby triggering the external charging device's response mechanism to supply power or charge the vehicle.

[0057] like Figure 1 As shown, in one possible embodiment, the vehicle interface also includes resistor R4, resistor RC and switch S3, with one end of resistor R4 connected in parallel with switch S3 connected to the PE line and the other end connected to the CC line.

[0058] like Figure 1 As shown, in one possible embodiment, a fuse F1 is also provided on the line connecting the vehicle controller and the battery.

[0059] In this embodiment of the application, a vehicle includes a vehicle body and an on-board power supply device as described in Embodiment 1, which is disposed on the vehicle body.

[0060] like Figure 1 As shown, a vehicle low-battery start-up system includes a vehicle as described in Embodiment 1 and an external charging device. The external charging device includes a charging gun and a device controller. The charging gun is matched with the vehicle's interface for connection, and the device controller is connected to the CC terminal of the charging gun. The connection point between the device controller and the CC terminal of the charging gun is designated as detection point four. After the vehicle is connected to the external charging device, the on-board power supply unit sends a low-battery status signal to the external charging device via the CC line when it detects a low-battery state. Upon detecting the low-battery status signal, the device controller supplies power to the vehicle and charges the battery through the external charging device.

[0061] like Figure 1 As shown, in one possible embodiment, the external charging device is an AC charging pile. This aligns with the application scenario of high AC charging pile parking space ratio for electric vehicles and low battery voltage due to prolonged vehicle parking. The device controller is connected to the CP terminal of the charging gun via a switch K1 and a resistor R1 in sequence. The connection point between resistor R1 and the CP terminal of the charging gun is designated as detection point one. The device controller is also directly connected to detection point one.

[0062] like Figure 2 As shown, a method for starting a vehicle with a dead battery, employing the vehicle dead battery starting system as described in Embodiment 1, includes the following steps:

[0063] The external charging device is connected to the vehicle via a charging gun.

[0064] The vehicle controller detects the battery voltage to determine if the battery is low on charge.

[0065] If the battery voltage is less than or equal to the first preset threshold, it indicates that the battery is low on power, and the vehicle controller sends a low-power status signal to the external charging device.

[0066] After receiving a low-power signal, the external charging device provides power to the vehicle.

[0067] The on-board charger and DC-DC converter convert the electricity output from the external charging equipment into low-voltage DC power to power the vehicle's low-voltage system and charge the battery.

[0068] Example 2

[0069] like Figure 1 As shown, a vehicle low-battery start-up system includes an external charging device that also includes a switching power supply. The switching power supply is connected to the CP terminal of the charging gun via switch K2. After the charging gun is connected to the vehicle interface and started, the switching power supply supplies power to the vehicle controller in the on-board power supply unit through the CP line. After the charging gun is connected to the vehicle interface and the charging process begins, the switching power supply of the external charging device can provide the necessary power to the vehicle controller through the CP line. This design effectively solves the problem that the vehicle controller cannot function properly when the battery is completely depleted, or even when the voltage is close to 0V. In this situation, the traditional battery low-battery detection mechanism and the closing control of switch S2 (see GB / T 18487.1-2023) cannot be implemented, resulting in the AC charging pile being unable to provide the required power to the vehicle. By introducing a switching power supply and supplying power through the CP line, this invention ensures that the vehicle controller can function normally even when the battery is completely depleted, thus successfully realizing battery low-battery detection, switch control, and power supply from the AC charging pile.

[0070] The rest is the same as in Example 1.

[0071] like Figure 3 As shown, a method for starting a vehicle with a dead battery, employing the vehicle dead battery starting system as described in Embodiment 2, includes the following steps:

[0072] After the external charging device is connected to the vehicle via the charging gun, the switching power supply of the external charging device supplies power to the vehicle controller in the on-board power supply unit through the CP line.

[0073] The vehicle controller detects the battery voltage to determine if the battery is low on charge.

[0074] If the battery voltage is less than or equal to the first preset threshold, it indicates that the battery is low on power, and the vehicle controller sends a low-power status signal to the external charging device.

[0075] After receiving a low-power signal, the external charging device provides power to the vehicle.

[0076] The on-board charger and DC-DC converter convert the electricity output from the external charging equipment into low-voltage DC power to power the vehicle's low-voltage system and charge the battery.

[0077] In one possible embodiment, a vehicle battery-powered start-up method further includes:

[0078] When the vehicle controller detects that the battery voltage exceeds a second preset threshold, it wakes up the vehicle's low-voltage system and sends a battery charging mode signal to determine if the high-voltage power-on conditions are met. If so, high-voltage power-on is completed. After high-voltage power-on, the circuit between the control power supply and the vehicle controller is disconnected. The system then checks if the power battery requires charging. If the power battery does not require charging and the battery charging mode signal from the vehicle controller is valid, the vehicle maintains a high-voltage power-on state. The duration of this high-voltage power-on state is determined experimentally based on the battery's depleted voltage. This step helps to wake up the vehicle's low-voltage system and initiate the battery charging mode promptly when the battery voltage recovers to a certain level. This not only ensures the vehicle operates normally with sufficient power from the low-voltage system but also allows for flexible adjustment of the charging strategy based on the battery's depletion level, improving charging efficiency and battery lifespan. In battery charging mode, the system determines if the power battery requires charging and adjusts the charging strategy accordingly. If the power battery does not require charging, the vehicle maintains a high-voltage power-on state to supply power to the vehicle's low-voltage system; if the power battery requires charging, it can be charged first. This flexible charging strategy helps improve charging efficiency and energy utilization.

[0079] like Figure 4 As shown, the following explanation of the vehicle low-battery start system uses the vehicle controller as the battery management controller (BMS), the battery as a lead-acid battery, and the external charging equipment as an AC charging station as an example:

[0080] The vehicle low-battery start system provides 12V power to the battery management controller (BMD) via the CP line of the AC charging station. The BMD detects the lead-acid battery voltage. If the voltage is less than or equal to a first preset threshold (e.g., 11.5V, determined based on the lead-acid battery type), the BMD outputs a preset PWM signal (e.g., a PWM signal with voltage V2 and a 10% duty cycle) through the PWM wave generator and sends a low-battery status signal to the AC charging station via the CC line. The device controller in the AC charging station detects the low-battery status signal and determines to provide 220V AC power to the on-board charger. The on-board charger then starts outputting DC voltage to the DC-DC converter, which in turn outputs 14.5V DC voltage to power the vehicle's low-voltage system. After the vehicle starts, the BMD determines whether to enter charging mode or lead-acid battery charging mode based on the battery's charge level. This system and method solve the problem of vehicles failing to start due to a low-battery lead-acid battery.

[0081] like Figure 4 As shown below, the working process of this vehicle's low-battery start-up system is explained in detail:

[0082] (1) The vehicle controller is awakened

[0083] After the AC charging gun is connected to the vehicle and the AC charging station is started, the AC charging station provides 12V power to the battery management controller through the CP line. At this time, both the AC charging station switch K2 and the vehicle switch K3 are in the closed state.

[0084] (2) The vehicle was started without a dead battery.

[0085] After the battery management controller completes initialization, it detects the voltage of the lead-acid battery. If the voltage of the lead-acid battery is greater than the first preset threshold, the battery management controller controls the voltage at detection point three to be the continuous voltage of V1. At this time, the vehicle's switch K3 is disconnected. The AC charging pile's equipment controller detects the continuous voltage of V1 through monitoring point four, controls switch K2 to open and switch K1 to close, and the system enters the normal AC charging judgment mode.

[0086] (3) Vehicle start-up process when the battery is low

[0087] After the battery management controller (BMD) initialization is complete, if the detected lead-acid battery voltage is ≤11.5V, the BMD controls the PWM generator to output a PWM signal (e.g., a PWM signal with voltage V2 and a duty cycle of 10%), i.e., the PWM signal is detected at detection point three. At this time, the AC charging pile's device controller detects this PWM signal through detection point four, thus identifying that the vehicle's lead-acid battery is low on charge. At this point, switch K2 remains closed, switch K1 is open, and switches C1 (which controls the opening and closing of the live wire) and C2 (which controls the opening and closing of the neutral wire) are closed, providing 220V power to the vehicle. The on-board charger receives the 220V power, completes initialization, and outputs a DC voltage target value based on the current battery voltage value sent by the BMD. The DC-DC converter converts the DC output from the on-board charger into a low-voltage 14.5V DC power supply to the vehicle's low-voltage system, while simultaneously charging the lead-acid battery.

[0088] When the voltage of the lead-acid battery exceeds the second preset threshold (e.g., 12.5V, which is determined based on the lead-acid battery selection), the battery management controller wakes up the vehicle's low-voltage system via a CAN management message and sends a lead-acid battery charging mode signal to the vehicle controller. If the high-voltage power-on conditions are met, the battery management controller closes the main positive and main negative relays of the power battery pack to complete the high-voltage power-on. At this time, the battery management controller controls the voltage at detection point three to remain at V1 and disconnects switch K3. Simultaneously, the AC charging pile's equipment controller closes switch K1 and disconnects switch K2. Furthermore, the status of switch S2 controls the closing or opening of switches C1 and C2, specifically:

[0089] If switch S2 is closed, it indicates that the power battery needs charging, and then it enters AC charging mode.

[0090] If switch S2 is open, indicating that the power battery has no charging requirement, then switches C1 and C2 controlling the AC charging pile are open. If the low-voltage charging mode for the lead-acid battery sent by the battery management controller is valid, the vehicle maintains a high-voltage power-on state (at this time, the power battery supplies power to the lead-acid battery), and the duration is determined by experimental calibration of the lead-acid battery's depleted voltage value. After the battery is fully charged, the battery management controller sends a charging completion signal to the external charging equipment and / or other control systems of the vehicle via the CC line.

[0091] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for starting a vehicle when the battery is low, characterized in that, Includes the following steps: After the external charging device is connected to the vehicle via the charging gun, the switching power supply of the external charging device supplies power to the vehicle controller in the on-board power supply unit through the CP line. The vehicle controller detects the battery voltage to determine if the battery is low on charge. If the battery voltage is less than or equal to the first preset threshold, it indicates that the battery is low on power, and the vehicle controller sends a low-power status signal to the external charging device. Upon receiving the low-power signal, the external charging device provides power to the vehicle. The on-board charger and DC-DC converter convert the electricity output from the external charging equipment into low-voltage DC power to power the vehicle's low-voltage system and charge the battery at the same time. When the vehicle controller detects that the battery voltage is greater than the second preset threshold, the vehicle controller wakes up the vehicle's low-voltage system and sends a battery charging mode signal to determine whether the high-voltage power-on conditions are met. If they are met, the high-voltage power-on is completed. After the high-voltage power-on is completed, the circuit between the control power supply and the vehicle controller is disconnected. Determine if the power battery needs charging; If the power battery has no charging requirement and the battery charging mode sent by the vehicle controller is effective, the vehicle maintains a high-voltage power-on state, and the duration of the high-voltage power-on state is obtained by experimental calibration based on the battery depletion voltage value.

2. A vehicle low-battery start system, characterized in that, include: vehicle; An external charging device includes a charging gun and a device controller, wherein the charging gun is matched with the vehicle interface of the vehicle for connection, and the device controller is connected to the CC terminal of the charging gun. Wherein, after the vehicle is connected to the external charging device, the vehicle's on-board power supply device is used to send a low-power status signal to the external charging device through the CC line when it is determined that the battery is in a low-power state. After the device controller detects the low-power status signal, it supplies power to the vehicle and charges the battery through the external charging device. The system can execute the vehicle low-battery start-up method as described in claim 1.

3. The vehicle low-battery start system according to claim 2, characterized in that: The external charging device also includes a switching power supply, which is connected to the CP terminal of the charging gun via switch K2. After the charging gun is connected to the vehicle interface and started, the switching power supply supplies power to the vehicle controller in the on-board power supply device through the CP line.

4. The vehicle low-battery start system according to claim 3, characterized in that: The external charging device is an AC charging pile.

5. The vehicle low-battery start system according to claim 3, characterized in that: The vehicle-mounted power supply device includes: Storage battery; The vehicle controller is electrically connected to the battery and is used to detect the battery voltage and determine whether the battery is in a low-charge state based on the detected voltage. The vehicle interface is used to match the charging gun of an external charging device to achieve electrical connection between the on-board charger and the external charging device. An on-board charger, whose input end is connected to the vehicle interface, is used to convert AC power provided by external charging equipment into DC power. A DC-DC converter, whose input is connected to the output of the on-board charger and whose output is connected to the battery, is used to convert the DC power output by the on-board charger into voltage and current suitable for charging the battery. The vehicle controller detects that the external charging device is connected to the vehicle interface and the battery is in a depleted state, and allows the external charging device to charge the battery through the on-board charger and DC-DC converter.

6. The vehicle low-battery start system according to claim 5, characterized in that: The vehicle controller is also equipped with a PWM wave generation unit. When the battery is detected to be low on power, the PWM wave generation unit sends a preset PWM signal to the external charging device through the CC line to indicate the low battery status.

7. The vehicle low-battery start system according to claim 6, characterized in that: The vehicle controller is connected to the CP line via switch K3. When the external charging device is detected to be connected to the vehicle interface and switch K3 is in the closed state, the external charging device is allowed to directly power the vehicle controller through the CP line.

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