CN-121973673-A - Battery self-heating circuit, control method, device, system, vehicle and medium

Abstract

The embodiment of the invention provides a battery self-heating circuit, a control method, equipment, a system, a vehicle and a medium, wherein the battery self-heating circuit comprises a motor, an inverter and a capacitor, the inverter, the motor and the capacitor form a resonant circuit, the capacitor is also used for connecting a battery pack, so that the battery pack can be self-heated by utilizing the resonant circuit and charge and discharge of the battery pack in a low-temperature environment, the service performance of the battery pack at low temperature is improved, the voltages at two ends of the capacitor are configured to be changed based on the resonant frequency of the resonant circuit, and therefore, the charge and discharge current of the resonant circuit can be increased, the current flowing out of and flowing into the battery pack is increased, and the battery heating power is maximized.

Inventors

• LING HEPING
• PAN HUA
• ZHAO ZHIMENG
• LI JICHENG
• SONG JINGYUAN

Assignees

• 比亚迪股份有限公司

Dates

Publication Date

20260505

Application Date

20241031

Claims (20)

1. 1. A battery self-heating circuit is characterized by comprising a motor, an inverter and a capacitor; the inverter, the motor and the capacitor form a resonant circuit, and the capacitor is also used for being connected with a battery pack; the voltage across the capacitor is configured to vary based on the resonant frequency of the resonant tank.
2. 2. The self-heating circuit of a battery according to claim 1, wherein, The inverter includes a multiphase leg, and the resonant frequency of the resonant tank is varied based on a phase-offset angle of the multiphase leg.
3. 3. The self-heating circuit of a battery according to claim 2, wherein, The phase staggering angle of the multi-phase bridge arm is changed based on the frequency of the preset audio frequency.
4. 4. The self-heating circuit of a battery according to claim 1, wherein, The magnitude of the voltage across the capacitor is configured to vary based on the magnitude of the preset audio.
5. 5. The battery self-heating circuit according to claim 1, wherein the magnitude of the voltage across the capacitor is controlled by adjusting the duty cycle of the modulation signal corresponding to the inverter.
6. 6. The battery self-heating circuit of claim 2, wherein the operating mode of the battery self-heating circuit comprises a first mode, the voltage across the capacitor being configured to vary based on a resonant frequency of the resonant tank in the first mode.
7. 7. The battery self-heating circuit of claim 6, wherein the battery self-heating circuit is in the first mode if a self-heating power of the battery self-heating circuit is less than a preset power threshold.
8. 8. The battery self-heating circuit according to claim 2, wherein the battery pack, the capacitor, the inverter, and the motor are connected in series to form a self-heating circuit so that the capacitor participates in a charging process or a discharging process of the battery pack.
9. 9. The battery self-heating circuit according to claim 8, wherein one end of the battery pack is connected to one end of the capacitor, the other end of the capacitor is connected to the inverter, midpoints of each phase leg of the inverter are respectively connected to a multiphase motor coil of the motor, the multiphase motor coil is connected to a neutral point of the motor, and the neutral point of the motor is connected to the other end of the battery pack.
10. 10. The battery self-heating circuit according to claim 9, wherein a first switch is connected between a neutral point of the motor and the battery pack, and a second switch is connected between the capacitor and the battery pack; The operating mode of the battery self-heating circuit includes a first mode in which the first switch and the second switch are configured to conduct.
11. 11. The battery self-heating circuit of any of claims 1-10, further comprising a control module; and the control module is used for controlling the voltage at two ends of the capacitor to change according to the resonant frequency of the resonant circuit.
12. 12. A battery self-heating circuit control method, characterized by being applied to the battery self-heating circuit according to any one of claims 1 to 11, comprising: the voltage across the capacitor is controlled to vary, the voltage across the capacitor being configured to vary based on a resonant frequency of the resonant tank.
13. 13. The method according to claim 12, wherein the method further comprises: And determining the resonant frequency of the resonant circuit according to the phase dislocation angles of the multiphase bridge arms of the inverter.
14. 14. The method of claim 13, wherein the method further comprises: And controlling the phase staggering angle of the multiphase bridge arms of the inverter according to the frequency of the preset audio frequency.
15. 15. The method of claim 12, wherein said controlling the voltage across the capacitor to vary comprises: And controlling the voltage at two ends of the capacitor according to the amplitude of the preset audio frequency.
16. 16. The method of claim 12, wherein the magnitude of the voltage across the capacitor is controlled by adjusting a duty cycle of a modulation signal corresponding to the inverter.
17. 17. The method of claim 13, wherein the operating mode of the battery self-heating circuit comprises a first mode, the voltage across the capacitor being configured to vary based on a resonant frequency of the resonant tank in the first mode.
18. 18. The method of claim 17, wherein the battery self-heating circuit is in the first mode if the self-heating power of the battery self-heating circuit is less than a preset power threshold.
19. 19. The method of claim 13, wherein the battery pack, the capacitor, the inverter, and the motor are connected in series to form a self-heating loop such that the capacitor participates in a charging process or a discharging process of the battery pack.
20. 20. The method of claim 19, wherein one end of the battery pack is connected to one end of the capacitor, the other end of the capacitor is connected to the inverter, midpoints of each phase leg of the inverter are respectively connected to a multiphase motor coil of the motor, the multiphase motor coil is connected to a neutral point of the motor, and the neutral point of the motor is connected to the other end of the battery pack.

Description

Battery self-heating circuit, control method, device, system, vehicle and medium Technical Field The invention relates to the technical field of motor driving, in particular to a battery self-heating system, a battery self-heating control method, a vehicle and a medium. Background With the development and rapid popularization of electric automobiles, lithium ion-based power batteries are widely used. Due to the inherent characteristics of the battery, a low temperature environment may affect the charge and discharge efficiency of the battery. The lithium ion battery is sensitive to low temperature, the internal resistance of the lithium ion battery is sharply increased at low temperature, the dischargeable capacity and the charge and discharge performance are greatly limited, the dynamic performance of the electric automobile is insufficient in low temperature environment, the driving range is greatly shortened, the battery can not be charged almost at the temperature lower than-20 ℃, if the battery is charged forcibly, the internal short circuit is easily caused, and the potential safety hazard is caused. "low temperature anxiety" has become a pain point affecting the user experience in the market process of electric automobiles, so how to improve the service performance of batteries at low temperature is one of the key problems to be solved urgently. Disclosure of Invention In order to solve the problems, the embodiment of the invention discloses a self-heating circuit of a battery, a control method, equipment, a system, a vehicle and a medium. In a first aspect, an embodiment of the present invention provides a battery self-heating circuit, including a motor, an inverter, and a capacitor; the inverter, the motor and the capacitor form a resonant circuit, and the capacitor is also used for being connected with a battery pack; the voltage across the capacitor is configured to vary based on the resonant frequency of the resonant tank. Optionally, the inverter includes a multiphase leg, and the resonant frequency of the resonant tank is varied based on a phase-shifting angle of the multiphase leg. Optionally, the phase-staggering angle of the multiphase bridge arm is varied based on the frequency of the preset audio. Optionally, the magnitude of the voltage across the capacitor is configured to vary based on the magnitude of the preset audio. Optionally, the voltage across the capacitor is controlled by adjusting the duty ratio of the modulation signal corresponding to the inverter. Optionally, the operating mode of the battery self-heating circuit includes a first mode in which the voltage across the capacitor is configured to vary based on the resonant frequency of the resonant tank. Optionally, the battery self-heating circuit is in the first mode if the self-heating power of the battery self-heating circuit is less than a preset power threshold. Optionally, the battery pack, the capacitor, the inverter and the motor are connected in series to form a self-heating loop, so that the capacitor participates in a charging process or a discharging process of the battery pack. Optionally, one end of the battery pack is connected with one end of the capacitor, the other end of the capacitor is connected with the inverter, the middle point of each phase of bridge arm of the inverter is respectively connected with a multiphase motor coil of the motor, the multiphase motor coil is connected to a neutral point of the motor, and the neutral point of the motor is connected with the other end of the battery pack. Optionally, a first switch is connected between the neutral point of the motor and the battery pack, and a second switch is connected between the capacitor and the battery pack; The operating mode of the battery self-heating circuit includes a first mode in which the first switch and the second switch are configured to conduct. Optionally, the system further comprises a control module; and the control module is used for controlling the voltage at two ends of the capacitor to change according to the resonant frequency of the resonant circuit. In a second aspect, an embodiment of the present invention provides a method for controlling a self-heating circuit of a battery, which is applied to the self-heating circuit of a battery, and the method includes: the voltage across the capacitor is controlled to vary, the voltage across the capacitor being configured to vary based on a resonant frequency of the resonant tank. Optionally, the method further comprises: And determining the resonant frequency of the resonant circuit according to the phase dislocation angles of the multiphase bridge arms of the inverter. Optionally, the method further comprises: And controlling the phase staggering angle of the multiphase bridge arms of the inverter according to the frequency of the preset audio frequency. Optionally, the controlling the voltage across the capacitor to change includes: And controlling the voltage at two ends of