Battery electric vehicle and low-voltage storage battery recharging system therefor, and control method

Abstract

A low-voltage storage battery recharging system for a battery electric vehicle. The system comprises a first detection unit (1), a second detection unit (2), a first controller (3), a battery management system (4), a second controller (5), a traction battery (6), a DC / DC module (7) and a low-voltage storage battery (8), wherein a detection end of the first detection unit (1) is connected to a constant power source of a battery electric vehicle, and an output end thereof is connected to the first controller (3); a detection end of the second detection unit (2) is connected to a constant power source (9) of the battery electric vehicle, and an output end thereof is connected to the second controller (5); an input end of the battery management system is connected to the first controller (3), and an output end thereof is connected to the second controller (5); the traction battery (6) is sequentially connected to the DC / DC module (7) and the low-voltage storage battery (8); and an output end of the first controller (3) is connected to the DC / DC module (7). Further disclosed are a battery electric vehicle using the system, and a control method. The system can automatically charge a low-voltage storage battery regardless of whether a main power rocker switch is closed, thereby preventing battery drain of the low-voltage storage battery.

Description

Pure electric vehicles and their low-voltage battery charging systems and control methods

[0001] This application claims priority to Chinese patent application CN202411583533.7, filed on November 7, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of new energy vehicle technology, specifically to a low-voltage battery charging system and control method for pure electric vehicles, and to pure electric vehicles. Background Technology

[0003] Pure electric vehicles have numerous low-voltage electronic control units, resulting in a relatively large overall static current. When the low-voltage battery in a pure electric vehicle is depleted, its voltage is lower than normal. This low battery voltage prevents the onboard components and control units from activating properly, thus hindering the vehicle's startup.

[0004] When a pure electric vehicle is under 24-hour monitoring or constant-fire mode, it continuously consumes power from the low-voltage battery, leading to a complete battery drain. Once the low-voltage battery is depleted, it cannot be recharged by the main battery. This is because the main battery's ability to charge (recharge) the 24V low-voltage battery via the DC / DC module requires the battery management system (BMS) to be active and the main positive and negative relays to be engaged. When the low-voltage battery is depleted, the BMS cannot be activated, and sufficient voltage cannot be provided to engage the relays. Therefore, the main battery cannot form a high-voltage closed circuit, preventing the charging of the low-voltage battery and affecting the normal starting of the pure electric vehicle. Summary of the Invention

[0005] This invention provides a pure electric vehicle and its low-voltage battery charging system and control method to solve the technical problem that the low-voltage battery in existing pure electric vehicles is affected by the failure of the vehicle to start normally.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A low-voltage battery charging system for pure electric vehicles, wherein the low-voltage battery is connected to a power battery via a DC / DC module, and the charging system includes:

[0008] The first detection unit is used to detect the first voltage value of the constant power supply of pure electric vehicles.

[0009] A first controller is configured to generate a wake-up signal when the first voltage value is less than a set voltage threshold, and send the wake-up signal to a second controller;

[0010] The second controller is used to receive the wake-up signal sent by the first controller and control the DC / DC module to work according to the wake-up signal, so that the power battery charges the low-voltage battery through the DC / DC module.

[0011] Therefore, when the first detection unit detects that the first voltage of the constant power supply is lower than the set voltage threshold (e.g., 24V), the first controller wakes up the second controller, and the second controller controls the DC / DC module to work, so that the power battery charges the low-voltage battery, thereby avoiding the low-voltage battery from being depleted.

[0012] In some embodiments, the power supply system further includes a second detection unit, which is used to detect a second voltage value of the constant power supply of the pure electric vehicle;

[0013] The second controller is further configured to determine whether the first detection unit and the second detection unit are faulty based on the second voltage value and the wake-up signal. If not, the second controller controls the DC / DC module to work so that the power battery charges the low-voltage battery through the DC / DC module. If so, the second controller issues a fault alarm.

[0014] If the difference between the second voltage value and the voltage value corresponding to the wake-up signal (i.e., the first voltage value) is less than or equal to the set voltage difference threshold, it indicates that the voltage values ​​of the constant power supply detected by the first detection unit and the second detection unit are similar, and the first detection unit and the second detection unit are normal; if the difference between the second voltage value and the voltage value corresponding to the wake-up signal is greater than the set voltage difference threshold, it indicates that the voltage values ​​of the constant power supply detected by the first detection unit and the second detection unit are different, and the first detection unit and / or the second detection unit is faulty.

[0015] In some embodiments, the charging system further includes a battery management system, wherein the first controller is connected to the battery management system via a hardwire, and the battery management system is connected to the second controller via a hardwire;

[0016] The first controller is a controller for controlling the equipment in the rear compartment of the vehicle, and the second controller is a vehicle controller.

[0017] The controller (i.e., rear module) and vehicle controller (i.e., domain controller VCU) used to control the vehicle's rear compartment equipment are existing configurations in pure electric vehicles. This invention directly utilizes the rear module and domain controller already configured in the vehicle to achieve automatic charging of the low-voltage battery, making rational use of existing resources and saving costs. The first controller wakes up the battery management system via a hard-wired signal, and the battery management system wakes up the second controller via a hard-wired signal, reducing the load rate of the CAN bus between the first and second controllers and enhancing reliability.

[0018] In some embodiments, the second controller is electrically connected to the constant power supply via a first switch. The second controller is also configured to receive a switch closing signal and send it to the first controller when the first switch is closed, and to control the DC / DC module to work when the second voltage value is less than a set voltage threshold and the switch closing signal is received, so that the power battery charges the low-voltage battery through the DC / DC module.

[0019] The first controller is also configured not to generate a wake-up signal when the first voltage value is less than a set voltage threshold and the switch closure signal (i.e., a first-level signal is valid) is received.

[0020] In some embodiments, the second controller is further configured to record the time for each charging of the low-voltage battery by the power battery, and determine whether the low-voltage battery is faulty based on the interval between two adjacent charging times.

[0021] The second controller determines whether there is a fault in the lifespan of the low-voltage battery by measuring the time interval between two consecutive charging times. If the interval between two consecutive charging times is less than or equal to the set time threshold (e.g., 6 hours), it indicates that the lifespan of the low-voltage battery is faulty and needs to be replaced. If the interval between two consecutive charging times is greater than the set time threshold, it indicates that the lifespan of the low-voltage battery is not faulty.

[0022] Based on the same inventive concept, the present invention also provides a pure electric vehicle, wherein the vehicle is equipped with a low-voltage battery charging system as described above.

[0023] Based on the same inventive concept, the present invention also provides a control method for the low-voltage battery charging system of a pure electric vehicle as described above, comprising:

[0024] Obtain the first voltage value of the constant power supply for the electric vehicle;

[0025] A wake-up signal is generated when the first voltage value is less than a set voltage threshold;

[0026] The wake-up signal controls the operation of the DC / DC module, enabling the power battery to charge the low-voltage battery through the DC / DC module.

[0027] In some embodiments, the control method further includes:

[0028] Obtain the second voltage value of the constant power supply for the electric vehicle;

[0029] Determine whether the first detection unit and the second detection unit are faulty based on the second voltage value and the wake-up signal;

[0030] If not, the second controller controls the DC / DC module to operate, so that the power battery charges the low-voltage battery through the DC / DC module;

[0031] If so, the second controller issues a fault alarm; wherein, the first detection unit is used to detect the first voltage value, and the second detection unit is used to detect the second voltage value.

[0032] In some embodiments, the control method further includes:

[0033] When the first switch is closed, a switch closure signal is received;

[0034] When the second voltage value is less than the set voltage threshold, the DC / DC module is controlled to work, so that the power battery charges the low-voltage battery through the DC / DC module.

[0035] No wake-up signal is generated when the first voltage value is less than the set voltage threshold.

[0036] In some embodiments, the control method further includes:

[0037] Record the time for each charging of the low-voltage battery by the power battery, and determine whether the low-voltage battery is faulty based on the interval between two adjacent charging times;

[0038] If the interval between two consecutive charging times is less than or equal to the set time threshold, the low-voltage battery is faulty and needs to be replaced; if the interval between two consecutive charging times is greater than the set time threshold, the low-voltage battery is not faulty.

[0039] This invention has at least the following technical effects or advantages:

[0040] 1. When the first detection unit detects that the voltage of the constant power supply is lower than the set voltage threshold (24V), the first controller wakes up the second controller, and the second controller controls the DC / DC module to work, so that the power battery charges the low-voltage battery through the DC / DC module, thereby avoiding the low-voltage battery from being depleted.

[0041] 2. The first controller is used to control the equipment in the rear compartment of the vehicle, and the second controller is the vehicle controller. The automatic charging of the low-voltage battery is achieved by directly utilizing the rear compartment equipment controller and the vehicle controller that are originally configured in the vehicle, making reasonable use of existing resources and saving costs.

[0042] 3. The second controller is woken up by a hard-wired signal, which reduces the load on the CAN bus and enhances reliability.

[0043] 4. This invention uses only the first and second controllers for monitoring, resulting in fewer interaction nodes and enhanced reliability. Attached Figure Description

[0044] Figure 1 is a schematic diagram of the circuit structure of a low-voltage battery charging system for a pure electric vehicle according to an embodiment of the present invention. Detailed Implementation

[0045] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0046] Referring to Figure 1, a low-voltage battery charging system for a pure electric vehicle includes a first detection unit 1, a second detection unit 2, a first controller 3, a battery management system 4, a second controller 5, a power battery 6, a DC / DC module 7, and a low-voltage battery 8. The detection terminal of the first detection unit 1 is connected to the constant-power supply 9 of the pure electric vehicle, and its output terminal is connected to the first controller 3. The first detection unit 1 detects the first voltage value of the constant-power supply in real time. The detection terminal of the second detection unit 2 is connected to the constant-power supply 9 of the pure electric vehicle, and its output terminal is connected to the second controller 5. The second detection unit 2 detects the second voltage value of the constant-power supply in real time. The input terminal of the battery management system 4 is connected to the first controller 3, and its output terminal is connected to the second controller 5. The power battery 6 is connected to the DC / DC module 7, and the DC / DC module 7 is connected to the low-voltage battery 8. The output terminal of the second controller 5 is connected to the DC / DC module 7. The second controller 5 and the constant-power supply 9 are electrically connected via a first switch 10. In this invention, the first switch 10 is the main power rocker switch of the pure electric vehicle. The first controller 3 and the battery management system 4, and the battery management system 4 and the second controller 5 are connected by hard wires.

[0047] In a specific embodiment of the present invention, the first controller is a controller for controlling the equipment in the rear compartment of the vehicle (such as an air compressor, fan, warning lights, etc.), and the second controller is a vehicle controller. The controller for controlling the equipment in the rear compartment of the vehicle (i.e., the rear module) and the vehicle controller (i.e., the domain controller VCU) are both existing configurations of pure electric vehicles. The automatic charging of the low-voltage battery is achieved by directly utilizing the rear module and domain controller that are already configured in the vehicle, making reasonable use of existing resources and saving costs.

[0048] The control method for the low-voltage battery charging system of the above-mentioned pure electric vehicle is as follows:

[0049] When the first switch 10 is open, if the first voltage value of the constant power supply detected by the first detection unit 1 is less than the set voltage threshold (e.g., 24V), the first controller 3 generates a wake-up signal. The first controller 3 wakes up the battery management system 4 via a hardwired connection, and the battery management system 4 wakes up the second controller 5 via a hardwired connection. The second controller 5 controls the DC / DC module 7 to work, and the power battery 6 charges the low-voltage battery 8. The second controller 5 records the charging duration and charging time. When the charging duration is greater than or equal to the set duration threshold (e.g., 1 hour), it indicates that the low-voltage battery 8 has completed charging. The second controller 5 controls the DC / DC module 7 to stop working (i.e., the power battery 6 is powered off). Then, the second controller 5 controls the first controller 3 to stop outputting the wake-up signal via the CAN bus, the battery management system 4 is disconnected from the wake-up signal, and the second controller 5 is powered off.

[0050] When the first switch 10 is open, if the difference between the first voltage value of the constant power supply detected by the first detection unit 1 and the second voltage value of the constant power supply detected by the second detection unit 2 is greater than the set voltage difference threshold, it indicates that the voltage values ​​of the constant power supply detected by the first detection unit 1 and the second detection unit 2 are different, and the second controller 5 issues a fault alarm, indicating that the first detection unit 1 and / or the second detection unit 2 are faulty.

[0051] When the first switch 10 is closed, the key is not powered on. The second controller 5 receives the switch closure signal and sends it to the first controller 3 via the CAN bus. The first controller 3 does not output a wake-up signal. When the second voltage value of the constant power supply detected by the second detection unit 2 is less than the set voltage threshold, the second controller 5 controls the DC / DC module 7 to work, so that the power battery 6 charges the low-voltage battery 8 through the DC / DC module 7.

[0052] Therefore, regardless of whether the main power rocker switch is closed or open, the present invention can charge the low-voltage battery 8, thereby preventing the low-voltage battery from running out of power.

[0053] The second controller 5 determines whether the low-voltage battery 8 is faulty based on the interval between two consecutive charging times.

[0054] If the interval between two consecutive charging times is less than or equal to the set time threshold (e.g., 6 hours), it indicates that the charging interval of the low-voltage battery 8 is too short, the service life of the low-voltage battery 8 is greatly reduced, and the low-voltage battery needs to be replaced; if the interval between two consecutive charging times is greater than the set time threshold, it indicates that the charging interval of the low-voltage battery 8 is normal, and the low-voltage battery 8 has a longer service life.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-voltage battery charging system for a pure electric vehicle, wherein the low-voltage battery is connected to a power battery via a DC / DC module, characterized in that, The power replenishment system includes: The first detection unit is used to detect the first voltage value of the constant power supply of pure electric vehicles. A first controller is configured to generate a wake-up signal when the first voltage value is less than a set voltage threshold, and send the wake-up signal to a second controller; The second controller is used to receive the wake-up signal sent by the first controller and control the DC / DC module to work according to the wake-up signal, so that the power battery charges the low-voltage battery through the DC / DC module.

2. The low-voltage battery charging system for pure electric vehicles according to claim 1, characterized in that, The power supply system also includes a second detection unit, which is used to detect the second voltage value of the constant power supply of the pure electric vehicle. The second controller is further configured to determine whether the first detection unit and the second detection unit are faulty based on the second voltage value and the wake-up signal. If not, the second controller controls the DC / DC module to work so that the power battery charges the low-voltage battery through the DC / DC module. If so, the second controller issues a fault alarm.

3. The low-voltage battery charging system for pure electric vehicles according to claim 1, characterized in that, The charging system also includes a battery management system, wherein the first controller is connected to the battery management system via a hardwire, and the battery management system is connected to the second controller via a hardwire; The first controller is a controller for controlling the equipment in the rear compartment of the vehicle, and the second controller is a vehicle controller.

4. The low-voltage battery charging system for pure electric vehicles according to claim 1, characterized in that, The second controller is electrically connected to the constant-fire power supply via a first switch; The second controller is also configured to receive a switch closing signal and send it to the first controller when the first switch is closed, and to control the DC / DC module to operate when the second voltage value is less than a set voltage threshold and the switch closing signal is received, so that the power battery charges the low-voltage battery through the DC / DC module. The first controller is further configured not to generate a wake-up signal when the first voltage value is less than a set voltage threshold and the switch closure signal is received.

5. The low-voltage battery charging system for pure electric vehicles according to any one of claims 1 to 4, characterized in that, The second controller is also used to record the time for each charging of the low-voltage battery by the power battery, and to determine whether the low-voltage battery is faulty based on the interval between two adjacent charging times.

6. A pure electric vehicle, characterized in that, The vehicle is equipped with a low-voltage battery charging system for pure electric vehicles as described in any one of claims 1 to 5.

7. A control method for a low-voltage battery charging system for a pure electric vehicle as described in any one of claims 1 to 5, characterized in that, The control method includes: Obtain the first voltage value of the constant power supply for the electric vehicle; A wake-up signal is generated when the first voltage value is less than a set voltage threshold; The wake-up signal controls the operation of the DC / DC module, enabling the power battery to charge the low-voltage battery through the DC / DC module.

8. The control method for the low-voltage battery charging system of a pure electric vehicle according to claim 7, characterized in that, The control method further includes: Obtain the second voltage value of the constant power supply for the electric vehicle; Determine whether the first detection unit and the second detection unit are faulty based on the second voltage value and the wake-up signal; If not, the second controller controls the DC / DC module to operate, so that the power battery charges the low-voltage battery through the DC / DC module; If so, the second controller issues a fault alarm; wherein, the first detection unit is used to detect the first voltage value, and the second detection unit is used to detect the second voltage value.

9. The control method for the low-voltage battery charging system of a pure electric vehicle according to claim 7, characterized in that, The control method further includes: When the first switch is closed, a switch closure signal is received; When the second voltage value is less than the set voltage threshold, the DC / DC module is controlled to work, so that the power battery charges the low-voltage battery through the DC / DC module. No wake-up signal is generated when the first voltage value is less than the set voltage threshold.

10. The control method for the low-voltage battery charging system of a pure electric vehicle according to any one of claims 7 to 9, characterized in that, The control method further includes: Record the time for each charging of the low-voltage battery by the power battery, and determine whether the low-voltage battery is faulty based on the interval between two adjacent charging times; If the interval between two consecutive charging times is less than or equal to the set time threshold, the low-voltage battery is faulty and needs to be replaced; if the interval between two consecutive charging times is greater than the set time threshold, the low-voltage battery is not faulty.

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