Low-voltage power supply system of new energy vehicle

Abstract

The invention discloses a low-voltage power supply system of a new energy vehicle, which is characterized in that a built-in DCDC is integrated in an integral structure of a power battery, and the built-in DCDC is respectively connected with a low-voltage storage battery, a vehicle DCDC, the power battery, a vehicle control unit and a battery management system; the output end of the power battery is connected with the input end of the vehicle DCDC and the input end of the built-in DCDC. The output end of the vehicle DCDC and the output end of the built-in DCDC are respectively connected with a low-voltage storage battery and a low-voltage power utilization system; after the vehicle is powered off, power supply to the low-voltage storage battery and the low-voltage power utilization system can still be achieved through control of the battery management system, repeated charging and discharging of the low-voltage storage battery are avoided, the service life of the storage battery is prolonged, and the risk that the vehicle cannot be started due to feeding of the low-voltage storage battery is reduced.

Description

Technical Field

[0001] The present invention relates to a low-voltage power supply system for a new energy vehicle, and particularly relates to a low-voltage power supply system for a new energy vehicle. Background Art

[0002] In the prior art, the low-voltage system of new energy vehicles is powered by a 12V small battery and a vehicle DCDC controller, which together provide power to the battery management system. When the vehicle is powered on, the vehicle DCDC controller is awakened and starts working, competing with the 12V small battery to power the low-voltage system. However, after the vehicle is powered off, the vehicle DCDC controller cannot work. At this time, only the 12V small battery supplies power to the low-voltage system of the new energy vehicle. If the vehicle is turned on in the warning mode or the BMS is turned on in the 24-hour monitoring mode after the vehicle is powered off, since the battery management system is in the on mode, it continuously consumes electricity and the power consumption is high, there is a risk that the small battery will be depleted, causing the vehicle to be unable to start. To circumvent this problem, it is necessary to frequently control the high voltage on the vehicle and charge the small battery through the vehicle DCDC controller to avoid depletion of the small battery. However, this method will cause the vehicle to be frequently powered on and off, and the continuous charging and discharging of the small battery will affect the service life of the small battery. Summary of the Invention

[0003] The purpose of the present invention is to provide a low-voltage power supply system for new energy vehicles, which is used to solve the technical problems of small batteries being easily depleted and having a short service life.

[0004] The technical solution of the present invention to solve the technical problem is: A low-voltage power supply system for a new energy vehicle includes: a low-voltage battery, a vehicle DC-DC converter, a power battery, and a battery management system. The vehicle DC-DC converter is respectively connected to the low-voltage battery, the power battery, the vehicle controller, and the battery management system. The system also includes: a built-in DC-DC converter, which is integrated within the overall power battery structure and respectively connected to the low-voltage battery, the vehicle DC-DC converter, the power battery, the vehicle controller, and the battery management system. The output end of the power battery is respectively connected to the input end of the vehicle DC-DC converter and the input end of the built-in DC-DC converter. The output end of the vehicle DC-DC converter and the output end of the built-in DC-DC converter are respectively connected to the low-voltage battery and the low-voltage power system. The vehicle controller reads the vehicle's upper and lower high-voltage instructions and sends the upper and lower high-voltage control instructions to the battery management system; The battery management system receives control instructions for upper and lower high voltage, and controls the opening and closing of the built-in DCDC controller and the vehicle DCDC controller; Built-in DCDC, used to convert the high voltage of the power battery into low voltage to power the low-voltage power system and low-voltage battery; Vehicle DCDC is used to convert the high voltage of the power battery into low voltage to supply power to the low-voltage power system and low-voltage battery; Power batteries are used to provide original power for vehicles.

[0005] Preferably, the output end of the power battery is connected to the input end of the vehicle DCDC in the following manner: the positive pole of the power battery is connected to the input end of the first contactor and the input end of the third contactor, the output end of the third contactor is connected to the input end of the first resistor, the output end of the first contactor and the output end of the first resistor are both connected to the positive pole of the vehicle DCDC; the negative pole of the power battery is connected to the input end of the second contactor, and the output end of the second contactor is connected to the negative pole of the vehicle DCDC.

[0006] Preferably, the output end of the power battery is connected to the input end of the built-in DCDC in the following manner: the positive output end of the power battery is directly connected to the positive input end of the built-in DCDC; the negative output end of the power battery is directly connected to the negative input end of the built-in DCDC.

[0007] Preferably, the low-voltage battery is a 12V low-voltage battery.

[0008] Preferably, the battery management system is integrated into the overall structure of the power battery.

[0009] The beneficial effects of the present invention are as follows: by integrating the built-in DCDC into the overall structure of the power battery, the built-in DCDC is respectively connected to the low-voltage battery, the vehicle DCDC, the power battery, the vehicle controller, and the battery management system; the output end of the power battery is respectively connected to the input end of the vehicle DCDC and the input end of the built-in DCDC; the output end of the vehicle DCDC and the output end of the built-in DCDC are respectively connected to the low-voltage battery and the low-voltage power system; after the vehicle is powered off, the low-voltage battery and the low-voltage power system can still be powered by the control of the battery management system, thereby avoiding repeated charging and discharging of the low-voltage battery, thereby increasing the service life of the battery and reducing the risk of the vehicle being unable to start due to power supply from the low-voltage battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of system connection of the present invention; Figure 2 It is a schematic diagram of the control process in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0011] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0012] like Figure 1As shown, the present invention discloses a low-voltage power supply system for a new energy vehicle, comprising: a low-voltage battery, a vehicle DC-DC converter, a power battery, and a battery management system (BMS). The vehicle DC-DC converter is respectively connected to the low-voltage battery, the power battery, the vehicle controller, and the battery management system (BMS). The system also comprises: a built-in DC-DC converter, which is integrated into the overall structure of the power battery and is respectively connected to the low-voltage battery, the vehicle DC-DC converter, the power battery, the vehicle controller, and the battery management system (BMS). The output end of the power battery is respectively connected to the input end of the vehicle DC-DC converter and the input end of the built-in DC-DC converter. The output end of the vehicle DC-DC converter and the output end of the built-in DC-DC converter are respectively connected to the low-voltage battery and the low-voltage power system. The low-voltage battery is a 12V low-voltage battery. The power battery output is connected to the vehicle DC / DC input in the following manner: the positive electrode of the power battery is connected to the input of the first contactor K1 and the input of the third contactor K3; the output of the third contactor K3 is connected to the input of the first resistor; the output of the first contactor K1 and the output of the first resistor are both connected to the positive electrode of the vehicle DC / DC; the negative electrode of the power battery is connected to the input of the second contactor K2; the output of the second contactor K2 is connected to the negative electrode of the vehicle DC / DC. The power battery output is connected to the input of the built-in DC / DC in the following manner: the positive output of the power battery is directly connected to the positive input of the built-in DC / DC; and the negative output of the power battery is directly connected to the negative input of the built-in DC / DC.

[0013] The vehicle controller reads the vehicle's upper and lower high-voltage instructions and sends the upper and lower high-voltage control instructions to the battery management system (BMS); The battery management system (BMS) receives control instructions for upper and lower high voltages, and controls the opening and closing of the built-in DCDC controller and the vehicle DCDC controller. The battery management system (BMS) is integrated into the overall structure of the power battery. Built-in DCDC, used to convert the high voltage of the power battery into low voltage to power the low-voltage power system and low-voltage battery; Vehicle DCDC is used to convert the high voltage of the power battery into low voltage to supply power to the low-voltage power system and low-voltage battery; Power batteries are used to provide original power for vehicles.

[0014] Example 1: like Figure 2As shown, after the vehicle controller reads the vehicle's high-voltage up and down commands, the battery management system (BMS) controls the contactors to apply high voltage, turning on and off the internal DC-DC circuit and the vehicle DC-DC circuit according to vehicle requirements. Specifically, when the vehicle is powered on, the BMS first closes the second contactor K2, then the third contactor K3, then the first contactor K1, and finally the third contactor K3. This process ensures a smooth vehicle power-up and protects related circuits from damage. After the vehicle is powered on, the power battery provides power to the vehicle DC-DC circuit. After the vehicle DC-DC circuit and the internal DC-DC circuit receive the vehicle power-on signal from the battery management system (BMS), the internal DC-DC circuit shuts down and the vehicle DC-DC circuit turns on. At this point, the power supply circuit for the vehicle DC-DC circuit competes with the low-voltage battery to supply power to the vehicle's low-voltage electrical system. If the low-voltage battery's charge is low, the vehicle DC-DC circuit simultaneously charges the low-voltage battery while supplying power to the low-voltage electrical system. This ensures that the low-voltage battery maintains a high charge level while the vehicle is powered on, preventing it from running low. When the vehicle is powered off, the battery management system (BMS) controls the main positive first contactor K1 and the main negative second contactor K2 to open. After the vehicle is powered off, the vehicle DC-DC converter and the internal DC-DC converter receive the vehicle power-off signal from the BMS. The internal DC-DC converter turns on, while the vehicle DC-DC converter turns off. At this point, the power supply circuit for the internal DC-DC converter and the low-voltage battery compete for power, jointly supplying the low-voltage power system. If the low-voltage battery's charge level is low, the internal DC-DC converter not only supplies power to the low-voltage power system but also charges the low-voltage battery. This ensures that the low-voltage battery maintains a high charge level even when the vehicle is powered off, preventing a low-voltage battery charge that could affect the vehicle's next startup.

[0015] In addition, during the vehicle power-up process, if the vehicle's DC-DC converter shuts down due to a fault, the battery management system (BMS) can also control the built-in DC-DC converter to turn on and jointly power the battery management system. The relevant control processes of the battery management system involved are all existing technologies and will not be repeated here.

[0016] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

Claims

1. A low-voltage power supply system for new energy vehicles, comprising: A low-voltage battery, a vehicle DC-DC converter, a power battery, and a battery management system, wherein the vehicle DC-DC converter is respectively connected to the low-voltage battery, the power battery, the vehicle controller, and the battery management system. The system further comprises: a built-in DC-DC converter, which is integrated within the overall structure of the power battery and is respectively connected to the low-voltage battery, the vehicle DC-DC converter, the power battery, the vehicle controller, and the battery management system; an output end of the power battery is respectively connected to an input end of the vehicle DC-DC converter and an input end of the built-in DC-DC converter; and an output end of the vehicle DC-DC converter and an output end of the built-in DC-DC converter are respectively connected to the low-voltage battery and a low-voltage power system. The vehicle controller reads the vehicle's upper and lower high-voltage instructions and sends the upper and lower high-voltage control instructions to the battery management system; The battery management system receives control instructions for upper and lower high voltage, and controls the opening and closing of the built-in DCDC controller and the vehicle DCDC controller; Built-in DCDC, used to convert the high voltage of the power battery into low voltage to power the low-voltage power system and low-voltage battery; Vehicle DCDC is used to convert the high voltage of the power battery into low voltage to supply power to the low-voltage power system and low-voltage battery; Power batteries are used to provide original power for vehicles.

2. The low-voltage power supply system for new energy vehicles according to claim 1, characterized in that: The output end of the power battery is connected to the input end of the vehicle DCDC in a specific manner as follows: the positive pole of the power battery is connected to the input end of the first contactor and the input end of the third contactor, the output end of the third contactor is connected to the input end of the first resistor, and the output end of the first contactor and the output end of the first resistor are both connected to the positive pole of the vehicle DCDC; the negative pole of the power battery is connected to the input end of the second contactor, and the output end of the second contactor is connected to the negative pole of the vehicle DCDC.

3. The low-voltage power supply system for new energy vehicles according to claim 1, characterized in that: The output terminal of the power battery is connected to the input terminal of the built-in DCDC in the following manner: the positive output terminal of the power battery is directly connected to the positive input terminal of the built-in DCDC; the negative output terminal of the power battery is directly connected to the negative input terminal of the built-in DCDC.

4. The low-voltage power supply system for new energy vehicles according to claim 1, characterized in that: The low-voltage battery is a 12V low-voltage battery.

5. The low-voltage power supply system for new energy vehicles according to claim 1, characterized in that: The battery management system is integrated into the overall structure of the power battery.

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