Battery heating device and control method and circuit therefor, and power device

1 . A battery heating device, which is connected to a traction battery and configured to heat the traction battery, wherein the traction battery comprises a first battery cell and a second battery cell, the battery heating device comprising:

a heating module comprising a first bridge arm, a second bridge arm, and an energy storage element; and

a control module configured to control the first bridge arm and the second bridge arm, to form a circuit for discharging from the first battery cell to the energy storage element and a circuit for charging from the energy storage element and the first battery cell to the second battery cell, and/or to form a circuit for discharging from the second battery cell to the energy storage element and a circuit for charging from the energy storage element and the second battery cell to the first battery cell, for heating of the first battery cell and the second battery cell;

wherein a state switching switch is connected between the first end of the first battery cell and the first end of the second battery cell, or a state switching switch is connected between the second end of the first battery cell and the second end of the second battery cell; and wherein the control module is further configured to:

control the state switching switch to be opened, so that the first battery cell is connected in series with the second battery cell.

2 . The battery heating device according to claim 1 , wherein

a first end of the first bridge arm is connected to a first end of the first battery cell, a first end of the second bridge arm is connected to a first end of the second battery cell, and a second end of the first bridge arm, a second end of the second bridge arm, and a second end of the first battery cell are connected to a second end of the second battery cell, wherein the first bridge arm comprises a first sub-bridge arm and a second sub-bridge arm, and the second bridge arm comprises a third sub-bridge arm and a fourth sub-bridge arm; and

the first end of the first battery cell is a positive electrode of the first battery cell, the second end of the first battery cell is a negative electrode of the first battery cell, the first end of the second battery cell is a positive electrode of the second battery cell, and the second end of the second battery cell is a negative electrode of the second battery cell; or the first end of the first battery cell is a negative electrode of the first battery cell, the second end of the first battery cell is a positive electrode of the first battery cell, the first end of the second battery cell is a negative electrode of the second battery cell, and the second end of the second battery cell is a positive electrode of the second battery cell.

3 . The battery heating device according to claim 2 , wherein

a first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and a second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or

a first end of the energy storage element is connected to the second end of the first bridge arm, and a second end of the energy storage element is connected to the second end of the second bridge arm.

4 . The battery heating device according to claim 3 , wherein the control module is configured to:

control the first sub-bridge arm and the fourth sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the first battery cell, the first sub-bridge arm, the energy storage element, and the fourth sub-bridge arm, for discharging from the first battery cell to the energy storage element;

control the first sub-bridge arm and the third sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the first battery cell, the first sub-bridge arm, the energy storage element, the third sub-bridge arm, and the second battery cell, for charging from the first battery cell and the energy storage element to the second battery cell;

control the second sub-bridge arm and the third sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the second battery cell, the third sub-bridge arm, the energy storage element, and the second sub-bridge arm, for discharging from the second battery cell to the energy storage element; and

control the first sub-bridge arm and the third sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the second battery cell, the third sub-bridge arm, the energy storage element, the first sub-bridge arm, and the first battery cell, for charging from the second battery cell and the energy storage element to the first battery cell.

5 . The battery heating device according to claim 2 , wherein

a first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and a second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or

a first end of the energy storage element is connected to the first end of the first bridge arm, and a second end of the energy storage element is connected to the first end of the second bridge arm.

6 . The battery heating device according to claim 5 , wherein the control module is specifically configured to:

control the second sub-bridge arm and the third sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the first battery cell, the second sub-bridge arm, the energy storage element, and the third sub-bridge arm, for discharging from the first battery cell to the energy storage element;

control the second sub-bridge arm and the fourth sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the first battery cell, the second sub-bridge arm, the energy storage element, the fourth sub-bridge arm, and the second battery cell, for charging from the first battery cell and the energy storage element to the second battery cell;

control the first sub-bridge arm and the fourth sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the second battery cell, the fourth sub-bridge arm, the energy storage element, and the first sub-bridge arm, for discharging from the second battery cell to the energy storage element; and

control the second sub-bridge arm and the fourth sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the second battery cell, the fourth sub-bridge arm, the energy storage element, the second sub-bridge arm, and the first battery cell, for charging from the second battery cell and the energy storage element to the first battery cell.

7 . The battery heating device according to claim 2 , wherein

the first sub-bridge arm comprises a first switch transistor, the second sub-bridge arm comprises a second switch transistor, the third sub-bridge arm comprises a third switch transistor, and the fourth sub-bridge arm comprises a fourth switch transistor,

wherein the control module implements the switching on and off of the first sub-bridge arm, the second sub-bridge arm, the third sub-bridge arm, and the fourth sub-bridge arm respectively by controlling the first switch transistor, the second switch transistor, the third switch transistor, and the fourth switch transistor.

8 . The battery heating device according to claim 1 , wherein a second capacitor is connected in parallel to the first battery cell at the two ends, and a third capacitor is connected in parallel to the second battery cell at the two ends.

9 . A power device, comprising:

a traction battery comprising a first battery cell and a second battery cell;

a battery heating device according to claim 1 , which is connected to the traction battery and configured to heat the traction battery; and

a motor, wherein a drive circuit of the motor is connected to the traction battery, and the traction battery is configured to provide power to the drive circuit.

10 . A control method for a battery heating device, which is connected to a traction battery and configured to heat the traction battery, wherein the battery heating device comprises a first bridge arm, a second bridge arm, and an energy storage element, and the traction battery comprises a first battery cell and a second battery cell, the control method comprising:

controlling the first bridge arm and the second bridge arm, to form a circuit for discharging from the first battery cell to the energy storage element and a circuit for charging from the energy storage element and the first battery cell to the second battery cell, and/or to form a circuit for discharging from the second battery cell to the energy storage element and a circuit for charging from the energy storage element and the second battery cell to the first battery cell, for heating of the first battery cell and the second battery cell;

wherein a state switching switch is connected between the first end of the first battery cell and the first end of the second battery cell, or a state switching switch is connected between the second end of the first battery cell and the second end of the second battery cell; and wherein the control method further comprises:

controlling the state switching switch to be opened, so that the first battery cell is connected in series with the second battery cell.

11 . The control method according to claim 10 , wherein

a first end of the first bridge arm is connected to a first end of the first battery cell, a first end of the second bridge arm is connected to a first end of the second battery cell, and a second end of the first bridge arm, a second end of the second bridge arm, and a second end of the first battery cell are connected to a second end of the second battery cell, wherein the first bridge arm comprises a first sub-bridge arm and a second sub-bridge arm, and the second bridge arm comprises a third sub-bridge arm and a fourth sub-bridge arm; and

the first end of the first battery cell and the first end of the second battery cell are positive electrodes, and the second end of the first battery cell and the second end of the second battery cell are negative electrodes; or the first end of the first battery cell and the first end of the second battery cell are negative electrodes, and the second end of the first battery cell and the second end of the second battery cell are positive electrodes.

12 . The control method according to claim 11 , wherein

a first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and a second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or

a first end of the energy storage element is connected to the second end of the first bridge arm, and a second end of the energy storage element is connected to the second end of the second bridge arm.

13 . The control method according to claim 12 , wherein the controlling the first bridge arm and the second bridge arm comprises:

receiving a heating request message; and

generating a first control signal based on the heating request message, wherein the first control signal is used to:

control the first sub-bridge arm and the fourth sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the first battery cell, the first sub-bridge arm, the energy storage element, and the fourth sub-bridge arm, for discharging from the first battery cell to the energy storage element;

control the first sub-bridge arm and the third sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the first battery cell, the first sub-bridge arm, the energy storage element, the third sub-bridge arm, and the second battery cell, for charging from the first battery cell and the energy storage element to the second battery cell;

control the second sub-bridge arm and the third sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the second battery cell, the third sub-bridge arm, the energy storage element, and the second sub-bridge arm, for discharging from the second battery cell to the energy storage element; and

control the first sub-bridge arm and the third sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the second battery cell, the third sub-bridge arm, the energy storage element, the first sub-bridge arm, and the first battery cell, for charging from the second battery cell and the energy storage element to the first battery cell.

14 . The control method according to claim 13 , wherein the control method further comprises:

receiving a heating stop message; and

generating a second control signal based on the heating stop message, wherein the second control signal is used to control the battery heating device to stop heating the traction battery.

15 . The control method according to claim 11 , wherein

a first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and a second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or

a first end of the energy storage element is connected to the first end of the first bridge arm, and a second end of the energy storage element is connected to the first end of the second bridge arm.

16 . The control method according to claim 15 , wherein the controlling the first bridge arm and the second bridge arm comprises:

receiving a heating request message; and

generating a third control signal based on the heating request message, wherein the third control signal is used to:

control the second sub-bridge arm and the third sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the first battery cell, the second sub-bridge arm, the energy storage element, and the third sub-bridge arm, for discharging from the first battery cell to the energy storage element;

control the second sub-bridge arm and the fourth sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the first battery cell, the second sub-bridge arm, the energy storage element, the fourth sub-bridge arm, and the second battery cell, for charging from the first battery cell and the energy storage element to the second battery cell;

control the first sub-bridge arm and the fourth sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the second battery cell, the fourth sub-bridge arm, the energy storage element, and the first sub-bridge arm, for discharging from the second battery cell to the energy storage element; and

control the second sub-bridge arm and the fourth sub-bridge arm to be switched on at the same time, to form a circuit, which comprises the second battery cell, the fourth sub-bridge arm, the energy storage element, the second sub-bridge arm, and the first battery cell, for charging from the second battery cell and the energy storage element to the first battery cell.

17 . The control method according to claim 11 , wherein

the first sub-bridge arm comprises a first switch transistor, the second sub-bridge arm comprises a second switch transistor, the third sub-bridge arm comprises a third switch transistor, and the fourth sub-bridge arm comprises a fourth switch transistor,

wherein the switching on and off of the first sub-bridge arm, the second sub-bridge arm, the third sub-bridge arm, and the fourth sub-bridge arm are respectively implemented by controlling the first switch transistor, the second switch transistor, the third switch transistor, and the fourth switch transistor.

18 . The control method according to claim 10 , wherein a second capacitor is connected in parallel to the first battery cell at the two ends, and a third capacitor is connected in parallel to the second battery cell at the two ends.