Battery heating system and vehicle

Abstract

The application discloses a battery heating system and a vehicle, and the system comprises: a power battery comprising a first battery pack and a second battery pack connected in series; a first electric drive system comprising a first electric control and a first motor connected with the first electric control, and the first electric control is further connected with the first battery pack; a second electric drive system comprising a second electric control and a second motor connected with the second electric control, and the second electric control is further connected with the second battery pack; and a controller connected with the first electric control and the second electric control, respectively, for controlling the first electric control and the second electric control in a first mode to alternately execute a first state and a second state of the power battery, wherein the first state is that the first battery pack discharges and the second battery pack charges, and the second state is that the first battery pack charges and the second battery pack discharges. Thus, the system can improve the temperature rising rate of the power battery and stabilize the total voltage of the power battery.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and more particularly to a battery heating system and a vehicle. Background Technology

[0002] To improve the driving performance of electric vehicles, more and more multi-motor electric vehicles are entering the public eye. Multi-motor vehicles are known for their powerful performance. Powerful performance requires good charging and discharging performance of the battery. However, when the power battery is in a low-temperature environment below -10°C, its charging and discharging performance will drop significantly due to the decreased activity of the battery's positive and negative electrode materials and electrolyte.

[0003] Therefore, it is necessary to heat the power batteries of multi-motor electric vehicles to raise their temperature and ensure strong power in cold conditions. Furthermore, ensuring that the power batteries can quickly reach a suitable temperature in low-temperature environments is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to provide a battery heating system capable of increasing the temperature rise rate of a power battery and stabilizing the total voltage of the power battery.

[0005] The second objective of this invention is to provide a vehicle.

[0006] To achieve the above objectives, a first aspect of the present invention provides a battery heating system, the system comprising: a power battery, including a first battery pack and a second battery pack connected in series; a first electric drive system, the first electric drive system including a first electronic control unit and a first motor connected to the first electronic control unit, the first electronic control unit also being connected to the first battery pack; a second electric drive system, the second electric drive system including a second electronic control unit and a second motor connected to the second electronic control unit, the second electronic control unit also being connected to the second battery pack; and a controller, the controller being connected to both the first electronic control unit and the second electronic control unit, the controller being configured to: in a first mode, control the first electronic control unit and the second electronic control unit such that a first state and a second state of the power battery are alternately executed, wherein the first state is: the first battery pack is discharging and the second battery pack is charging; and the second state is: the first battery pack is charging and the second battery pack is discharging.

[0007] The battery heating system according to embodiments of the present invention can improve the temperature rise rate of the power battery and stabilize the total voltage of the power battery.

[0008] To achieve the above objectives, a second aspect of the present invention provides a vehicle comprising: the aforementioned battery heating system.

[0009] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0010] Figure 1 This is a topology diagram of the internal heating scheme;

[0011] Figure 2 This is a schematic diagram of the battery heating system according to the first embodiment of the present invention;

[0012] Figure 3 This is a topology diagram of the battery heating system of the first specific embodiment of the present invention;

[0013] Figure 4 This is a topology diagram of the battery heating system according to the second embodiment of the present invention;

[0014] Figure 5 This is a timing diagram of the battery heating system of the second embodiment of the present invention during the first time period of the control cycle in the second mode.

[0015] Figure 6 This is a timing diagram of the battery heating system of the second embodiment of the present invention during the second time period of the control cycle in the second mode.

[0016] Figure 7 This is a schematic diagram of the switch connection in the battery heating system of the second embodiment of the present invention;

[0017] Figure 8 This is a topology diagram of the battery heating system according to the third embodiment of the present invention;

[0018] Figure 9 This is a topology diagram of the battery heating system according to the fourth embodiment of the present invention;

[0019] Figure 10 This is a timing diagram of the battery heating system of the fourth embodiment of the present invention in the fourth mode, during the first time period of the control cycle;

[0020] Figure 11 This is a timing diagram of the second time period of the control cycle in the fourth mode of the battery heating system of the fourth embodiment of the present invention;

[0021] Figure 12 This is a topology diagram of the battery heating system according to the fifth embodiment of the present invention;

[0022] Figure 13 This is a topology diagram of the battery heating system according to the sixth embodiment of the present invention;

[0023] Figure 14This is a schematic diagram showing the connection of the third, fourth, and fifth switches in the battery heating system according to the sixth specific embodiment of the present invention;

[0024] Figure 15 This is a topology diagram of the battery heating system according to the seventh embodiment of the present invention.

[0025] Figure 16 This is a schematic diagram of the structure of a vehicle according to an embodiment of the present invention. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] The current mainstream heating methods for power batteries in multi-motor electric vehicles mainly include external heating and internal heating.

[0028] When using traditional external heating, the vehicle's high-voltage system needs to provide additional power to the battery heater because it uses a battery heater to heat the battery pack. It also needs to supply water or air ducts, pipelines, low-voltage systems, etc., which increases the total cost. In addition, due to the long water ducts and pipelines, heat loss is also large. Therefore, external heating has problems such as slow and long heating time, high cost, and low heating efficiency, and is increasingly unable to meet user needs.

[0029] Consequently, automakers have successively conducted research on internal heating systems. For example: See [link to related information] Figure 1 When the battery temperature falls below the set temperature threshold, the inverter IGBT bridge arm activates, controlling the energy to circulate and discharge between the motor inductor and the battery, achieving a self-heating effect for the battery pack. When internal heating is used, the self-heating principle involves the internal resistance of the battery pack generating heat when a large current flows through it, thus heating the battery pack. The heating amount is Q = I. 2 *R cell As can be seen from *t, in order to generate a greater amount of heat, a larger self-heating current is required while keeping the battery internal resistance and heating time constant.

[0030] However, see Figure 1 The energy is generated by the cyclic charging and discharging between the motor inductor and the battery. Therefore, the self-heating current cannot be large enough, resulting in poor self-heating effect.

[0031] Furthermore, in related technologies, battery voltage fluctuation ΔU=I*R cell In the total internal resistance R of the battery cellUnder constant conditions, the higher the battery current, the greater the fluctuation in battery voltage. This voltage fluctuation means the charging station cannot track the battery voltage in real time, leading to charging tripping or charging failure.

[0032] To address the aforementioned problems, this invention proposes a battery heating system and a vehicle. See the attached diagram below. Figure 2-16 This invention describes a battery heating system and vehicle according to embodiments of the present invention.

[0033] Figure 2 This is a schematic diagram of the structure of a battery heating system according to an embodiment of the present invention. Figure 2 As shown, the battery heating system 100 includes: a power battery 10, a first electric drive system 20, a second electric drive system 30, and a controller 40. The power battery 10 includes a first battery pack 11 and a second battery pack 12 connected in series. The first electric drive system 20 includes a first electronic control unit 21 and a first motor 22 connected to the first electronic control unit 21, which is also connected to the first battery pack 11. The second electric drive system 30 includes a second electronic control unit 31 and a second motor 32 connected to the second electronic control unit 31, which is also connected to the second battery pack 12. The controller 40 is connected to both the first electronic control unit 21 and the second electronic control unit 31.

[0034] In this embodiment, the controller 40 controls the first electronic control unit 21 and the second electronic control unit 31 in the first mode, so that the first state and the second state of the power battery 10 are executed alternately. The first state is: the first battery pack 11 is discharging and the second battery pack 12 is charging; the second state is: the first battery pack 11 is charging and the second battery pack 12 is discharging.

[0035] Specifically, in the first mode, the controller 40 controls the first electronic control unit 21 and the second electronic control unit 31 to alternate between the first and second states of the power battery 10. (See also...) Figure 3 When the power battery 10 is in its first state, the first battery pack 11 stores energy for the inductors of the first motor 22, and the inductors of the second motor 32 charge the second battery pack 12. When the power battery 10 is in its second state, the inductors of the first motor 22 charge the first battery pack 11, and the second battery pack 12 stores energy for the inductors of the second motor 32. Thus, self-heating is achieved through the first and second electric drive systems. The increased number of inductors involved in self-heating improves heating efficiency. Furthermore, the alternating charging and discharging of the first and second battery packs increases the cumulative current value compared to current values ​​in related technologies, thereby improving the rate of temperature rise of the power battery.

[0036] In this embodiment, in the first mode, the controller 40 controls the first electric drive system 20 to cause the first voltage change of the first battery pack 11 to be ±ΔU1, and controls the second electric drive system 30 to cause the second voltage change of the second battery pack 12 to be ±ΔU2, and the third voltage change of the power battery 10 to be ΔU. Then ΔU = +ΔU1 - ΔU2, or ΔU = -ΔU1 + ΔU2, where ΔU < ε, and ε is a preset voltage fluctuation threshold.

[0037] Therefore, in the first mode, the controller controls the first and second electronic controls, so that the first and second states of the power battery are executed alternately. That is, the two battery packs are always in a state where one battery pack is charging and the other is discharging. The two have a canceling effect, so the voltage change at both ends of the power battery is relatively small relative to the entire power battery. This does not affect the power battery from charging or driving while self-heating, and provides a basis for the coordination of self-heating and charging (when charging, the battery works at a suitable temperature, and the battery charging rate is increased) or the coordination of self-heating and driving (when driving, the battery works at a suitable temperature, which can ensure the driving range).

[0038] Figure 4 This is a topology diagram of the battery heating system according to the second embodiment of the present invention. Figure 4 As shown, in the first embodiment, Figure 3 Based on this, the battery heating system 100 may also include: a third electric drive system 50 and a fourth electric drive system 60.

[0039] The third electric drive system 50 includes a third electric control 51 and a third motor 52 connected to the third electric control 51. The first N line of the first motor 22 is connected to the third N line of the third motor 52. The positive terminal of the first battery pack 11 is connected to the first bus terminal of the first electric control 21 and the first bus terminal of the third electric control 51, respectively. The negative terminal of the first battery pack 11 is connected to the second bus terminal of the first electric control 21 and the second bus terminal of the third electric control 51, respectively.

[0040] The fourth electric drive system 60 includes a fourth electronic control 61 and a fourth motor 62 connected to the fourth electronic control 61; the second N line of the second motor 32 is connected to the fourth N line of the fourth motor 62; the positive terminal of the second battery pack 12 is connected to the first bus terminal of the second electronic control 31 and the first bus terminal of the fourth electronic control 61 respectively; and the negative terminal of the second battery pack 12 is connected to the second bus terminal of the second electronic control 31 and the second bus terminal of the fourth electronic control 61 respectively.

[0041] In this embodiment, the controller 40 is connected to the third electronic control unit 51 and the fourth electronic control unit 61 respectively. The controller 40 is also used to control the first electronic control unit 21, the second electronic control unit 31, the third electronic control unit 51 and the fourth electronic control unit 61 in the second mode, so that the first state and the second state of the power battery 10 are executed alternately.

[0042] Specifically, in the second mode, the controller 40 controls the first electronic control unit 21, the second electronic control unit 31, the third electronic control unit 51, and the fourth electronic control unit 61 to alternate between the first and second states of the power battery 10. See also... Figure 3 When the power battery 10 is in its first state, the first battery pack 11 stores energy for the inductors of the first motor 22 and the third motor 52, while the inductors of the second motor 32 and the fourth motor 62 charge the second battery pack 12. When the power battery 10 is in its second state, the inductors of the first motor 22 and the third motor 52 charge the first battery pack 11, while the second battery pack 12 stores energy for the inductors of the second motor 32 and the fourth motor 62. Thus, self-heating is achieved through the first, second, third, and fourth electric drive systems. The increased number of inductors involved in self-heating improves heating efficiency. Furthermore, the alternating charging and discharging of the first and second battery packs increases the cumulative current value compared to current values ​​in related technologies, thereby improving the rate of temperature rise of the power battery.

[0043] In this embodiment, the controller 40 is further configured to: in the second mode, control the first electric drive system 20 and the third electric drive system 50 to cause the first voltage change of the first battery pack 11 to be ±ΔU1, and control the second electric drive system 30 and the fourth electric drive system 60 to cause the second voltage change of the second battery pack 12 to be ±ΔU2, and the third voltage change of the power battery 10 to be ΔU, then ΔU=+ΔU1-ΔU2, or ΔU=-ΔU1+ΔU2, where ΔU<ε, and ε is a preset voltage fluctuation threshold.

[0044] Therefore, in the second mode, the controller controls the first, second, third, and fourth electronic controls, so that the first and second states of the power battery are executed alternately. That is, the two battery packs are always in a state where one battery pack is charging and the other is discharging. Thus, the voltage change at both ends of the power battery is relatively small relative to the entire power battery, and therefore does not affect the power battery from charging or driving while self-heating. This provides a basis for the coordination of self-heating and charging (when charging, the battery operates at a suitable temperature, and the battery charging rate is increased) or the coordination of self-heating and driving (when driving, the battery operates at a suitable temperature, which can ensure the driving range).

[0045] See Figure 4The first electrical control 21 includes a multi-phase first bridge arm, the first bridge arm includes a first upper switch and a first lower switch; the second electrical control 31 includes a multi-phase second bridge arm, the second bridge arm includes a second upper switch and a second lower switch; the third electrical control 51 includes a multi-phase third bridge arm, the third bridge arm includes a third upper switch and a third lower switch; and the fourth electrical control 61 includes a multi-phase fourth bridge arm, the fourth bridge arm includes a fourth upper switch and a fourth lower switch.

[0046] In this embodiment, the controller 40 is used to:

[0047] like Figure 5 As shown by the middle arrow, in the second mode, during the first time period of the control cycle, the first upper switch, the second lower switch, the third lower switch and the fourth upper switch are turned on, and the first lower switch, the second upper switch, the third upper switch and the fourth lower switch are turned off, so that the first battery pack 11 discharges and the second battery pack 12 is charged.

[0048] like Figure 6 As shown by the middle arrow, in the second mode, during the second time period of the control cycle, the first lower switch, the second upper switch, the third upper switch and the fourth lower switch are turned on, and the first upper switch, the second lower switch, the third lower switch and the fourth upper switch are turned off, so that the first battery pack 11 is charged and the second battery pack 12 is discharged.

[0049] Specifically, in the second mode, within the control cycle, such as Figure 5-6 Through multiple cycles of the circuit indicated by the middle arrow, the first battery pack 11, the first motor 22, and the third motor 52 complete the charging and discharging of energy, while the second battery pack 12, the second motor 32, and the fourth motor 62 complete the charging and discharging of energy. Through this energy cycle, the internal resistance of the battery packs heats up, causing the battery pack temperature to rise. The motor inductors also heat up, leading to an increase in the temperature of the heat circulation system and ultimately, an increase in the temperature of the power battery 10. This achieves self-heating of the power battery.

[0050] In addition, in the second mode, during the first time period of the control cycle, the first electric drive system 20 and the third electric drive system 50 cause the voltage of the first battery pack 11 to drop, and the first voltage change ΔU1 = I1*R cell1 The second electric drive system 30 and the fourth electric drive system 60 cause the voltage of the second battery pack 12 to rise, and the amount of voltage change ΔU2 = I2*R cell2 As long as I1*R is guaranteed cell1 =I2*R cell2 Then the third voltage change ΔU of the power battery 10 is 0.

[0051] Similarly, in the second mode, during the second time period of the control cycle, the first electric drive system and the third drive system cause the voltage of the first battery pack 11 to rise, and the first voltage change ΔU1 = I1*R cell1 The second and fourth electric drive systems cause the voltage of the second battery pack 12 to drop, and the amount of voltage drop ΔU2=I2*R cell2 As long as I1*R is guaranteed cell1 =I2*R cell2 Then the third voltage change ΔU of the power battery 10 is 0.

[0052] Therefore, by means of the control cycle in the second mode, Figure 5-6 The cyclical movement of the middle arrow circuit completes the cyclical charging and discharging of energy between the power battery and the motor inductor, ensuring the stability of the total voltage of the power battery (i.e., the third voltage change) and realizing the self-heating of the power battery.

[0053] It should be noted that when the power battery 10 includes not just two battery packs, but three, four, ... n, there are correspondingly n motors and electronic controls matched with it, where n is an integer greater than 1. To ensure the stability of the total voltage of the power battery 10, the operation of the upper and lower switching transistors in the multi-phase bridge arm of the electronic control is controlled to ensure I1*R cell1 +……+I n *R celln =I 1’ (R cell1 +……+R celln That's it. When n motors and electronic controllers are connected in parallel to the same power battery 10, control the current flowing through each electronic controller to ensure I1*R cell1 +I2*R cell2 =(I 1’ +……+I n’ (R) cell1 +R cell2 That's it. When n motors and electronic controllers are connected in parallel to the same first battery pack 11 or second battery pack 12, control the current flowing through each electronic controller to ensure (I 1.1 +……+I 1.n )*R cell1 +I2*R cell2 =I 1’ (R cell1 +R cell2 ) or I1*R cell1 +(I 2.1 +……+I 2.n )*R cell2 =I 1’ (R cell1 +R cell2 That's all.

[0054] In addition, when the total voltage of the power battery is stable, direct charging of the power battery 10 using the DC charging port will not cause problems such as tripping or charging failure.

[0055] As an example, see Figure 7 The battery heating system 100 may further include: a first switch K1, a second switch K2, a first changeover switch S1, and a second changeover switch S2.

[0056] The first switch K1 is located between the first N line and the third N line; the second switch K2 is located between the second N line and the fourth N line; the first terminal a of the first changeover switch S1 is connected to the second bus terminal of the first electronic control 21 and the second bus terminal of the third electronic control 51 respectively, and the second terminal of the first changeover switch S1 is selectively connected to the negative terminal of the first battery pack 11 and the negative terminal of the second battery pack 12; the first terminal a of the second changeover switch S2 is connected to the first bus terminal of the second electronic control and the first bus terminal of the fourth electronic control respectively, and the second terminal of the second changeover switch S2 is selectively connected to the positive terminal of the first battery pack 11 and the positive terminal of the second battery pack 12.

[0057] See Figure 7 The controller 40 is also used to: control the first switch K1 and the second switch K2 to be disconnected, and control the first changeover switch S1 to be connected to the negative terminal of the second battery pack 12, and control the second changeover switch S2 to be connected to the positive terminal of the first battery pack 11, and control the first electronic control 21, the second electronic control 31, the third electronic control 51 and the fourth electronic control 61 to drive the first motor 22, the second motor 32, the third motor 52 and the fourth motor 62 in a coordinated manner.

[0058] Specifically, the controller 40 controls the first switch K1 and the second switch K2 to open, and controls the first changeover switch S1 to connect to the negative terminal of the second battery pack 12, and controls the second changeover switch S2 to connect to the positive terminal of the first battery pack 11. At this time, the first electric drive system 20 and the third electric drive system 50, along with the second electric drive system 30 and the fourth electric drive system 60, are all connected in parallel to the power battery 10 connected in series between the first battery pack 11 and the second battery pack 12. The vehicle can be driven using any combination of the two electric drive systems as needed.

[0059] In this example, the controller 40 is also used to: control the first switch K1 and the second switch K2 to close, control the first changeover switch S1 to connect to the negative terminal of the first battery pack 11, control the second changeover switch S2 to connect to the positive terminal of the second battery pack 12, and control the first electronic control 21, the second electronic control 31, the third electronic control 51 and the fourth electronic control 61 to drive the first motor 22, the second motor 32, the third motor 52 and the fourth motor 62 in a coordinated manner.

[0060] Specifically, controller 40 controls the first switch K1 and the second switch K2 to close, and controls the first changeover switch S1 to connect to the negative terminal of the first battery pack 11, and controls the second changeover switch S2 to connect to the positive terminal of the second battery pack 12. At this time, the first electric drive system 20 and the third electric drive system 50 are both connected in parallel to the first battery pack 11, and the two are connected through the motor neutral line (i.e., the first N line of the first motor 22 is connected to the third N line of the third motor 52); the second electric drive system 30 and the fourth electric drive system 60 are both connected in parallel to the second battery pack 12, and the two are connected through the motor neutral line (i.e., the second N line of the second motor 32 is connected to the fourth N line of the fourth motor 62). That is to say, the first electric drive system 20 and the third electric drive system 50 form the same heating sequence, and the second electric drive system 30 and the fourth electric drive system 60 form the same heating sequence, and the two heating sequences are alternately oscillating for heating.

[0061] Figure 8 This is a topology diagram of the battery heating system according to the third embodiment of the present invention. Figure 8 As shown, in the first embodiment, Figure 3 Based on this, the battery heating system 100 may also include: a fifth electric drive system 70.

[0062] The fifth electric drive system 70 includes a fifth electric control 71 and a fifth motor 72 connected to the fifth electric control 71. The positive terminal of the first battery pack 11 is connected to the first bus terminal of the fifth electric control 71, and the negative terminal of the second battery pack 12 is connected to the second bus terminal of the fifth electric control 71.

[0063] In this embodiment, the controller 40 is connected to the fifth electronic control unit 71. The controller 40 is used to control the first electronic control unit 21, the second electronic control unit 31 and the fifth electronic control unit 71 in the third mode, so that the third state and the fourth state of the power battery 10 are executed alternately. The third state is: the power battery 10 is discharging and the first battery pack 11 and the second battery pack 12 are charging; the fourth state is: the power battery 10 is charging and the first battery pack 11 and the second battery pack 12 are discharging.

[0064] Specifically, the controller 40 controls the first electronic control unit 21, the second electronic control unit 31, and the fifth electronic control unit 71 in three modes, so that the third and fourth states of the power battery 10 are executed alternately. When the power battery 10 is in the third state, the power battery 10 stores energy for the inductor of the fifth motor 72, the inductor of the first motor 22 charges the first battery pack 11, and the inductor of the second motor 32 charges the second battery pack 12; when the power battery 10 is in the fourth state, the inductor of the fifth motor 72 charges the power battery 10, the first battery pack 11 stores energy for the inductor of the first motor 22, and the second battery pack 12 stores energy for the inductor of the second motor 32. Therefore, self-heating is achieved through the first, second, third, fourth, and fifth electric drive systems. The heating efficiency is improved due to the increased number of inductors involved in the self-heating process. In addition, the temperature rise rate of the power battery is increased by alternating charging and discharging of the power battery and the first and second battery packs, as the cumulative current value of the power battery and the two battery packs is higher than that in related technologies.

[0065] In this embodiment, the controller is further configured to: in the third mode, control the first electric drive system 20 to make the first voltage change of the first battery pack 11 ±ΔU1, control the second electric drive system 30 to make the second voltage change of the second battery pack 12 ±ΔU2, control the fifth electric drive system 70 to make the third voltage change of the power battery 10 ±ΔU3, and the fourth voltage change of the power battery 10 ΔU, then ΔU=+ΔU3-ΔU1-ΔU2, or ΔU=-ΔU3+ΔU1+ΔU2, where ΔU<ε, and ε is a preset voltage fluctuation threshold.

[0066] Therefore, in the third mode, the controller controls the first, second, and fifth electronic controls, causing the third and fourth states of the power battery to be executed alternately. That is, the power battery and the two battery packs are always in a state of power battery discharging and the two battery packs charging, or power battery charging and the two battery packs discharging. Thus, the voltage change at both ends of the power battery is relatively small relative to the entire power battery, and therefore does not affect the power battery's charging or driving operation while self-heating. This provides a basis for the coordination of self-heating and charging (when charging, the battery operates at a suitable temperature, and the battery charging rate is increased) or the coordination of self-heating and driving (when driving, the battery operates at a suitable temperature, which can ensure the driving range).

[0067] As an example, the controller 40 is also used to: in the fifth mode, control the fifth electronic control 71 to drive the vehicle via the fifth motor 72, and control the first electronic control 21 and the second electronic control 31 so that the first state and the second state of the power battery 10 are executed alternately to achieve self-heating of the power battery 10. The first state is: the first battery pack 11 is discharging and the second battery pack 12 is charging; the second state is: the first battery pack 11 is charging and the second battery pack 12 is discharging.

[0068] Specifically, in the fifth mode, the controller 40 controls the fifth electronic control unit 71 to drive the vehicle via the fifth motor 72, and controls the first electronic control unit 21 and the second electronic control unit 31, so that the first state and the second state of the power battery 10 are executed alternately to achieve self-heating of the power battery 10. When the power battery 10 is in the first state, the first battery pack 11 stores energy for the inductor of the first motor 22, and the inductor of the second motor 32 charges the second battery pack 12; when the power battery 10 is in the second state, the inductor of the first motor 22 charges the first battery pack 11, and the second battery pack 12 stores energy for the inductor of the second motor 32. Thus, while driving the vehicle, the temperature rise rate of the power battery is increased.

[0069] Figure 9 This is a topology diagram of the battery heating system according to the fourth embodiment of the present invention. Figure 9 As shown, in the third embodiment, Figure 8 Based on this, the battery heating system 100 may also include: a third electric drive system 50 and a fourth electric drive system 60.

[0070] The third electric drive system 50 includes a third electric control 51 and a third motor 52 connected to the third electric control 51. The first N line of the first motor 22 is connected to the third N line of the third motor 52. The positive terminal of the first battery pack 11 is connected to the first bus terminal of the first electric control 21 and the first bus terminal of the third electric control 51, respectively. The negative terminal of the first battery pack 11 is connected to the second bus terminal of the first electric control 21 and the second bus terminal of the third electric control 51, respectively.

[0071] The fourth electric drive system 60 includes a fourth electronic control 61 and a fourth motor 62 connected to the fourth electronic control 61; the second N line of the second motor 32 is connected to the fourth N line of the fourth motor 62; the positive terminal of the second battery pack 12 is connected to the first bus terminal of the second electronic control 31 and the first bus terminal of the fourth electronic control 61 respectively; and the negative terminal of the second battery pack 12 is connected to the second bus terminal of the second electronic control 31 and the second bus terminal of the fourth electronic control 61 respectively.

[0072] In this embodiment, the controller 40 is connected to the third electronic control unit 51 and the fourth electronic control unit 61. The controller 40 is used to control the first electronic control unit 21, the second electronic control unit 31, the third electronic control unit 51, the fourth electronic control unit 61 and the fifth electronic control unit 71 in the fourth mode, so that the third state and the fourth state of the power battery 10 are executed alternately. The third state is: the power battery 10 is discharging and the first battery pack 11 and the second battery pack 12 are charging; the fourth state is: the power battery 10 is charging and the first battery pack 11 and the second battery pack 12 are discharging.

[0073] Specifically, in the fourth mode, the controller 40 controls the first electronic control unit 21, the second electronic control unit 31, the third electronic control unit 51, the fourth electronic control unit 61, and the fifth electronic control unit 71, so that the third and fourth states of the power battery 10 are executed alternately. When the power battery 10 is in the third state, the power battery 10 stores energy for the inductor of the fifth motor 72, the inductors of the first motor 22 and the third motor 52 charge the first battery pack 11, and the inductors of the second motor 32 and the fourth motor 62 charge the second battery pack 12. When the power battery 10 is in the fourth state, the inductor of the fifth motor 72 charges the power battery 10, the first battery pack 11 stores energy for the inductors of the first motor 22 and the third motor 52, and the second battery pack 12 stores energy for the inductors of the second motor 32 and the fourth motor 62. Therefore, self-heating is achieved through the first, second, third, and fourth electric drive systems. The heating efficiency is improved due to the increased number of inductors involved in the self-heating process. In addition, the temperature rise rate of the power battery is increased by alternating charging and discharging of the power battery and the first and second battery packs, as the cumulative current value of the power battery and the two battery packs is higher than that in related technologies.

[0074] In this embodiment, the controller 40 is further configured to: in the fourth mode, control the first electric drive system and the third electric drive system to cause the first voltage change of the first battery pack to be ±ΔU1, control the second electric drive system and the fourth electric drive system to cause the second voltage change of the second battery pack to be ±ΔU2, control the fifth electric drive system to cause the third voltage change of the power battery to be ±ΔU3, and the fourth voltage change of the power battery to be ΔU, then ΔU=+ΔU3-ΔU1-ΔU2, or ΔU=-ΔU3+ΔU1+ΔU2, where ΔU<ε, and ε is a preset voltage fluctuation threshold.

[0075] Therefore, in the fourth mode, the controller controls the first, second, third, fourth, and fifth electronic controllers 61 and 71, so that the first and second states of the power battery are executed alternately. That is, the power battery and the two battery packs are always in a state of power battery discharging and the two battery packs charging, or power battery charging and the two battery packs discharging. Thus, the voltage change at both ends of the power battery is relatively small relative to the entire power battery, and therefore does not affect the power battery's charging or driving operation while self-heating. This provides a basis for the coordination of self-heating and charging (when charging, the battery operates at a suitable temperature, and the battery charging rate is increased) or the coordination of self-heating and driving (when driving, the battery operates at a suitable temperature, which can ensure the driving range).

[0076] See Figure 9 The first electrical control unit 21 includes a multi-phase first bridge arm, which includes a first upper switch and a first lower switch; the second electrical control unit 31 includes a multi-phase second bridge arm, which includes a second upper switch and a second lower switch; the third electrical control unit 51 includes a multi-phase third bridge arm, which includes a third upper switch and a third lower switch; the fourth electrical control unit 61 includes a multi-phase fourth bridge arm, which includes a fourth upper switch and a fourth lower switch; the fifth electrical control unit 71 includes a first-phase fifth bridge arm 711, a second-phase fifth bridge arm 712, and a third-phase fifth bridge arm 713. The first-phase fifth bridge arm 711 includes a first-phase upper switch G11 and a first-phase lower switch G12; the second-phase fifth bridge arm 712 includes a second-phase upper switch G21 and a second-phase lower switch G22; and the third-phase fifth bridge arm 713 includes a third-phase upper switch G31 and a third-phase lower switch G32.

[0077] like Figure 10 As shown by the middle arrow, in the fourth mode, during the first time period of the control cycle, the first upper switch, the second upper switch, the third lower switch, the fourth lower switch, the first phase upper switch G11, the second phase lower switch G22, and the third phase lower switch G32 are turned on, and the first lower switch, the second lower switch, the third upper switch, the fourth upper switch, the first phase lower switch G12, the second phase upper switch G21, and the third phase upper switch G31 are turned off, so that the power battery 10 is charged and the first battery pack 11 and the second battery pack 12 are discharged.

[0078] like Figure 11As shown by the middle arrow, in the fourth mode, during the second time period of the control cycle, the first lower switch, the second lower switch, the third upper switch, the fourth upper switch, the first phase lower switch G12, the second phase upper switch G21, and the third phase upper switch G31 are turned on, and the first upper switch, the second upper switch, the third lower switch, the fourth lower switch, the first phase upper switch G11, the second phase lower switch G22, and the third phase lower switch G32 are turned off, so that the power battery 10 is discharged and the first battery pack 11 and the second battery pack 12 are charged.

[0079] Specifically, in the fourth mode, within the control cycle, such as Figure 10-11 In the multiple cycles of the circuit indicated by the middle arrow, the first battery pack 11, the first motor 22, and the third motor 52 complete the charging and discharging of energy; the second battery pack 12, the second motor 32, and the fourth motor 62 complete the charging and discharging of energy; and the power battery 10 and the fifth motor 72 complete the charging and discharging of energy. Through the above energy cycle, the internal resistance of the battery pack heats up, the battery pack temperature rises, the motor inductance heats up, the temperature of the heat circulation system rises, and the temperature of the power battery 10 rises.

[0080] In addition, in the fourth mode, during the first time period of the control cycle, the first electric drive system 20 and the third electric drive system 50 cause the voltage of the first battery pack 11 to drop, and the first voltage change ΔU1 = I1*R cell1 The second electric drive system 30 and the fourth electric drive system 60 cause the voltage of the second battery pack 12 to drop, and the amount of voltage drop ΔU2=I2*R cell2 The fifth electric drive system 70 increases the voltage of the power battery 10, and the third voltage change ΔU3 = I 1’ *(R cell1 +R cell2 As long as I1*R is guaranteed cell1 +I2*R cell2 =I 1’ *(R cell1 +R cell2 If the voltage change of the power battery 10 is 0, then the fourth voltage change is 0.

[0081] Similarly, in the fourth mode, during the second time period of the control cycle, the first electric drive system 20 and the third electric drive system 50 cause the first battery pack 11 to rise, and the first voltage change ΔU1 = I1*R cell1 The second electric drive system 30 and the fourth electric drive system 60 cause the voltage of the second battery pack 12 to rise, and the amount of voltage change ΔU2 = I2*R cell2 The fifth drive system 70 causes the voltage of the power battery 10 to drop, and the third voltage change ΔU3 = I 1’ *(R cell1 +Rcell2 As long as I1*R is guaranteed cell1 +I2*R cell2 =I 1’ *(R cell1 +R cell2 If ), then the fourth voltage change ΔU of the power battery 10 is 0.

[0082] Therefore, by controlling the cycle in the fourth mode, such as Figure 10-11 The cyclical movement of the circuit indicated by the middle arrow completes the cyclical charging and discharging of energy between the power battery and the motor inductor. It is also evident that, regardless of whether it's in the first or second time period of the control cycle in the fourth mode, one part of the circuit discharges both battery packs or the power battery while another part charges the power battery or both battery packs. In other words, the power battery is alternately charging and discharging at the same time. Through the preceding analysis, by controlling the actions of the aforementioned bridge arms to ensure the controllability of the charging and discharging current of each battery pack, the stability of the total voltage of the power battery (i.e., the fourth voltage change) can be guaranteed.

[0083] As an example, the controller 40 is also used to: in the sixth mode, control the fifth electronic control 71 to drive the vehicle via the fifth motor 72, and control the first electronic control 21, the second electronic control 31, the third electronic control 51 and the fourth electronic control 61 so that the first state and the second state of the power battery 10 are executed alternately to achieve self-heating of the power battery 10. The first state is: the first battery pack 11 is discharging and the second battery pack 12 is charging; the second state is: the first battery pack 11 is charging and the second battery pack 12 is discharging.

[0084] Specifically, in the sixth mode, the controller 40 controls the fifth electronic control unit 71 to drive the vehicle via the fifth motor 72, and controls the first electronic control unit 21 and the second electronic control unit 31 so that the first state and the second state of the power battery 10 are executed alternately to achieve self-heating of the power battery 10. When the first state of the power battery 10 is executed, the first battery pack 11 stores energy for the inductors of the first motor 22 and the third motor 52, and the inductors of the second motor 32 and the fourth motor 62 charge the second battery pack 12. When the second state of the power battery 10 is executed, the inductors of the first motor 22 and the third motor 52 charge the first battery pack 11, and the second battery pack 12 stores energy for the inductors of the second motor 32 and the fourth motor 62. Therefore, while driving the vehicle through the fifth electric drive system, self-heating is achieved through the first, second, third, and fourth electric drive systems. As the number of inductors participating in self-heating increases, the heating efficiency is improved. In addition, through the alternating charging and discharging of the first and second battery packs, the cumulative current value of the two battery packs is increased relative to the current value in related technologies, thereby improving the temperature rise rate of the power battery.

[0085] It should be noted that when the battery heating system 100 is operating in the above-mentioned self-heating modes (first mode, second mode, third mode, and fourth mode) and the drive-simultaneous self-heating modes (fifth mode and sixth mode), the maximum heating current is the total current limit value of the multi-phase inductance of the motor.

[0086] Figure 12 This is a topology diagram of the battery heating system according to the fifth embodiment of the present invention. Figure 12 As shown, in the first embodiment, Figure 3 Based on this, the battery heating system 100 may further include: a DC charging port 80, and a first end of the DC charging port 80 (e.g., Figure 12 The positive terminal of the DC charging port 80 is connected to the positive terminal of the first battery pack 11, and the second terminal of the DC charging port 80 (such as...) Figure 12 The negative terminal of the DC charging port 80 is connected to the negative terminal of the second battery pack 12;

[0087] In this embodiment, the controller 40 is used to: control the first electronic control 21 and the second electronic control 31 in the seventh mode, so that the first state and the second state of the power battery 10 are executed alternately to realize the self-heating of the power battery 10 and to charge the power battery 10 through the DC charging port 80. The first state is: the first battery pack 11 is discharging and the second battery pack 12 is charging; the second state is: the first battery pack 11 is charging and the second battery pack 12 is discharging.

[0088] Specifically, in the seventh mode, the controller 40 controls the first electronic control unit 21 and the second electronic control unit 31, causing the first and second states of the power battery 10 to be executed alternately to achieve self-heating of the power battery 10. When the power battery 10 is in the first state, the first battery pack 11 stores energy for the inductor of the first motor 22, and the inductor of the second motor 32 charges the second battery pack 12. When the power battery 10 is in the second state, the inductor of the first motor 22 charges the first battery pack 11, and the second battery pack 12 stores energy for the inductor of the second motor 32. The power battery 10 is also charged through the DC charging port 80. Thus, by alternating between the first and second states of the power battery and by adding a DC charging port, the synergy between direct charging and self-heating of the power battery is achieved.

[0089] Figure 13 This is a topology diagram of the battery heating system according to the sixth embodiment of the present invention. Figure 13 As shown, in the first embodiment, Figure 3 In addition to the above, the battery heating system 100 may also include: a DC charging port 80 and a boost circuit 90.

[0090] The boost circuit 90 includes an inductor 91 and a bridge arm 92, with the first end of the inductor 91 connected to the first end of the DC charging port 80 (e.g., ...). Figure 13 The positive terminal of the DC charging port 80 is connected to the inductor 91, the second end of the inductor 91 is connected to the midpoint of the bridge arm 92, the first end of the bridge arm 92 is connected to the positive terminal of the first battery pack 11, and the second end of the bridge arm 92 is connected to the negative terminal of the second battery pack 12 and the second end of the DC charging port 80 (as shown in the image). Figure 13 Connect the negative terminal of the DC charging port 80.

[0091] It should be noted that, see Figure 13 In this embodiment, the bridge arm of the sixth electronic control is reused as the bridge arm 92 of the boost circuit 90, and the inductance of the sixth motor is reused as the inductance 92 of the boost circuit 90.

[0092] In this embodiment, the controller 40 is used to: control the first electronic control 21 and the second electronic control 31 in the eighth mode, so that the first state and the second state of the power battery 10 are executed alternately to realize the self-heating of the power battery 10, and to perform boost charging for the power battery 10 through the DC charging port 80 and the control of the boost circuit 90.

[0093] Specifically, in the eighth mode, the controller 40 controls the first electronic control unit 21 and the second electronic control unit 31, causing the first and second states of the power battery 10 to be executed alternately to achieve self-heating of the power battery 10. When the power battery 10 is in the first state, the first battery pack 11 stores energy for the inductor of the first motor 22, and the inductor of the second motor 32 charges the second battery pack 12. When the power battery 10 is in the second state, the inductor of the first motor 22 charges the first battery pack 11, and the second battery pack 12 stores energy for the inductor of the second motor 32. Furthermore, the power battery 10 is boost-charged via the DC charging port 80 and the control boost circuit 90. Thus, by alternating the first and second states of the power battery and by adding the DC charging port and boost circuit, boost charging and self-heating of the power battery are achieved synergistically.

[0094] As an example, see Figure 14 The battery heating system 100 may also include: a third switch K3, a fourth switch K4 and a fifth switch K5.

[0095] Specifically, the first end of the third switch K3 is connected to the first end of the DC charging port 80, and the second end of the third switch K3 is connected to the first end of the bridge arm 92 and the positive terminal of the first battery pack 11, respectively; the first end of the fourth switch K4 is connected to the first end of the DC charging port 80, and the second end of the fourth switch K4 is connected to the first end of the inductor 91; the first end of the fifth switch K5 is connected to the second end of the DC charging port 80, and the second end of the fifth switch K5 is connected to the second end of the bridge arm 91 and the negative terminal of the second battery pack 12.

[0096] Specifically, when the third switch K3 and the fifth switch K5 are closed and the fourth switch K4 is open, direct charging and self-heating of the power battery are coordinated (see...). Figure 12 When the third switch K3 is open and the fourth switch K4 and the fifth switch K5 are closed, boost charging and self-heating of the power battery are achieved in tandem (see...). Figure 13 Thus, through the third, fourth, and fifth switches, the synergy between direct charging and power battery self-heating, or the synergy between boost charging and power battery self-heating, can be achieved.

[0097] Figure 15 This is a topology diagram of the battery heating system according to the seventh embodiment of the present invention. Figure 15 As shown, in the sixth embodiment, Figure 13 Based on this, the battery heating system 100 may also include: a third electric drive system 50 and a fourth electric drive system 60.

[0098] The third electric drive system 50 includes a third electric control 51 and a third motor 52 connected to the third electric control 51. The first N line of the first motor 22 is connected to the third N line of the third motor 52. The positive terminal of the first battery pack 11 is connected to the first bus terminal of the first electric control 21 and the first bus terminal of the third electric control 51, respectively. The negative terminal of the first battery pack 11 is connected to the second bus terminal of the first electric control 21 and the second bus terminal of the third electric control 51, respectively.

[0099] The fourth electric drive system 60 includes a fourth electronic control 61 and a fourth motor 62 connected to the fourth electronic control 61; the second N line of the second motor 32 is connected to the fourth N line of the fourth motor 62; the positive terminal of the second battery pack 12 is connected to the first bus terminal of the second electronic control 31 and the first bus terminal of the fourth electronic control 61 respectively; and the negative terminal of the second battery pack 12 is connected to the second bus terminal of the second electronic control 31 and the second bus terminal of the fourth electronic control 61 respectively.

[0100] In this embodiment, the controller 40 is connected to the third electronic control unit 51 and the fourth electronic control unit 61 respectively. The controller 40 is used to: control the first electronic control unit 21, the second electronic control unit 31, the third electronic control unit 51 and the fourth electronic control unit 61 in the ninth mode, so that the first state and the second state of the power battery 10 are executed alternately to realize the self-heating of the power battery 10, and control the boost circuit 90 to boost the charging of the power battery 10. The first state is: the first battery pack 11 is discharging and the second battery pack 12 is charging; the second state is: the first battery pack 11 is charging and the second battery pack 12 is discharging.

[0101] Specifically, in the ninth mode, the controller 40 controls the first electronic control unit 21, the second electronic control unit 31, the third electronic control unit 51, and the fourth electronic control unit 61, causing the first and second states of the power battery 10 to be executed alternately to achieve self-heating of the power battery 10. Specifically, when the power battery 10 is in the first state, the first battery pack 11 stores energy for the inductors of the first motor 22 and the third motor 52, while the inductors of the second motor 32 and the fourth motor 62 charge the second battery pack 12. When the power battery 10 is in the second state, the inductors of the first motor 22 and the third motor 52 charge the first battery pack 11, while the second battery pack 12 stores energy for the inductors of the second motor 32 and the fourth motor 62. Thus, by adding the third and fourth electric drive systems, the synergy between multiplexed electric drive boost charging and power battery self-heating is achieved.

[0102] In summary, by controlling the first and second electronic controls in the first mode to make the first and second states of the power battery alternate, or by controlling the first, second, third, and fourth electronic controls in the second mode to make the first and second states of the power battery alternate, or by controlling the first, second, third, and fifth electronic controls in the third mode to make the third and fourth states of the power battery alternate, or by controlling the first, second, third, fourth, and fifth electronic controls in the fourth mode to make the third and fourth states of the power battery alternate, the temperature rise rate of the power battery can be improved.

[0103] In the fifth mode, the fifth electronic control unit is controlled to drive the vehicle via the fifth motor, and the first and second electronic control units are controlled so that the first and second states of the power battery are executed alternately to achieve self-heating of the power battery. Alternatively, in the sixth mode, the fifth electronic control unit is controlled to drive the vehicle via the fifth motor, and the first and second electronic control units are controlled so that the first and second states of the power battery are executed alternately to achieve self-heating of the power battery. This can improve the temperature rise rate of the power battery while driving the vehicle.

[0104] In the seventh mode, the first and second electronic controls are controlled so that the first and second states of the power battery are executed alternately to achieve self-heating of the power battery and charging of the power battery through the DC charging port, thus achieving the synergy of direct charging and self-heating of the power battery.

[0105] In the eighth mode, the first and second electronic controls are controlled so that the first and second states of the power battery are executed alternately to achieve self-heating of the power battery. The power battery is also boosted through the DC charging port and the boost circuit, thus achieving the synergy of boost charging and self-heating of the power battery.

[0106] In the ninth mode, the first, second, third and fourth electronic controls are controlled so that the first and second states of the power battery are executed alternately to achieve self-heating of the power battery, and the boost circuit is controlled to boost the power battery for charging. This enables the synergy between the reused electric drive boost charging and the power battery self-heating.

[0107] Figure 16 This is a structural schematic diagram of a vehicle according to an embodiment of the present invention. Figure 16 As shown, vehicle 200 includes the aforementioned battery heating system 100.

[0108] The vehicle in this embodiment of the invention, through a battery heating system, can increase the temperature rise rate of the power battery and stabilize the total voltage of the power battery.

[0109] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0110] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0111] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0112] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0113] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0114] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A battery heating system, characterized in that, The system includes: The power battery includes a first battery pack and a second battery pack connected in series. A first electric drive system, the first electric drive system including a first electronic control and a first motor connected to the first electronic control, the first electronic control also being connected to the first battery pack; The second electric drive system includes a second electronic control unit and a second motor connected to the second electronic control unit. The second electronic control unit is also connected to the second battery pack. A controller, which is connected to the first electronic control unit and the second electronic control unit respectively, is used to: control the first electronic control unit and the second electronic control unit in a first mode, such that the first state and the second state of the power battery are executed alternately, wherein the first state is: the first battery pack is discharging and the second battery pack is charging; and the second state is: the first battery pack is charging and the second battery pack is discharging. The third electric drive system includes a third electric control unit and a third motor connected to the third electric control unit. The first N line of the first motor is connected to the third N line of the third motor. The positive terminal of the first battery pack is connected to the first bus terminal of the first electric control unit and the first bus terminal of the third electric control unit, respectively. The negative terminal of the first battery pack is connected to the second bus terminal of the first electric control unit and the second bus terminal of the third electric control unit, respectively. A fourth electric drive system, comprising a fourth electronic control unit and a fourth motor connected to the fourth electronic control unit; the second N line of the second motor is connected to the fourth N line of the fourth motor; the positive terminal of the second battery pack is connected to the first bus terminal of the second electronic control unit and the first bus terminal of the fourth electronic control unit respectively; the negative terminal of the second battery pack is connected to the second bus terminal of the second electronic control unit and the second bus terminal of the fourth electronic control unit respectively. The controller is connected to the third and fourth electronic controllers respectively, and the controller is also used to: control the first, second, third and fourth electronic controllers in the second mode, so that the first and second states of the power battery are executed alternately.

2. The battery heating system as described in claim 1, characterized in that, The controller is further configured to: in the first mode, control the first electric drive system to cause a first voltage change of ±ΔU1 in the first battery pack, and control the second electric drive system to cause a second voltage change of ±ΔU2 in the second battery pack, and the third voltage change of the power battery is ΔU, then ΔU = +ΔU1 - ΔU2, or ΔU = -ΔU1 + ΔU2, where ΔU < ε, and ε is a preset voltage fluctuation threshold.

3. The battery heating system as described in claim 1, characterized in that, The controller is further configured to: in the second mode, control the first electric drive system and the third electric drive system to cause the first voltage change of the first battery pack to be ±ΔU1, and control the second electric drive system and the fourth electric drive system to cause the second voltage change of the second battery pack to be ±ΔU2, and the third voltage change of the power battery to be ΔU, then ΔU=+ΔU1-ΔU2, or ΔU=-ΔU1+ΔU2, where ΔU<ε, and ε is a preset voltage fluctuation threshold.

4. The battery heating system as described in claim 1, characterized in that, The first electronic control unit includes a multi-phase first bridge arm, the first bridge arm including a first upper switch and a first lower switch; the second electronic control unit includes a multi-phase second bridge arm, the second bridge arm including a second upper switch and a second lower switch; the third electronic control unit includes a multi-phase third bridge arm, the third bridge arm including a third upper switch and a third lower switch; and the fourth electronic control unit includes a multi-phase fourth bridge arm, the fourth bridge arm including a fourth upper switch and a fourth lower switch. The controller is used for: In the second mode, during the first time period of the control cycle, the first upper switch, the second lower switch, the third lower switch and the fourth upper switch are turned on, and the first lower switch, the second upper switch, the third upper switch and the fourth lower switch are turned off, so that the first battery pack is discharged and the second battery pack is charged. In the second mode, during the second time period of the control cycle, the first lower switch, the second upper switch, the third upper switch, and the fourth lower switch are turned on, and the first upper switch, the second lower switch, the third lower switch, and the fourth upper switch are turned off, so that the first battery pack is charged and the second battery pack is discharged.

5. The battery heating system as described in claim 1, characterized in that, The system also includes: The fifth electric drive system includes a fifth electronic control unit and a fifth motor connected to the fifth electronic control unit. The positive terminal of the first battery pack is connected to the first busbar of the fifth electronic control unit, and the negative terminal of the second battery pack is connected to the second busbar of the fifth electronic control unit. The controller is connected to the fifth electronic control unit. The controller is used to control the first electronic control unit, the second electronic control unit, and the fifth electronic control unit in the third mode, so that the third state and the fourth state of the power battery are executed alternately. The third state is: the power battery is discharging, and the first battery pack and the second battery pack are charging; the fourth state is: the power battery is charging, and the first battery pack and the second battery pack are discharging.

6. The battery heating system as described in claim 5, characterized in that, The controller is further configured to: in the third mode, control the first electric drive system to cause a first voltage change of ±ΔU1 in the first battery pack, control the second electric drive system to cause a second voltage change of ±ΔU2 in the second battery pack, control the fifth electric drive system to cause a third voltage change of ±ΔU3 in the power battery, and the fourth voltage change of the power battery is ΔU, then ΔU = +ΔU3 - ΔU1 - ΔU2, or ΔU = -ΔU3 + ΔU1 + ΔU2, where ΔU < ε, and ε is a preset voltage fluctuation threshold.

7. The battery heating system as described in claim 5, characterized in that, The controller is used to: in the fourth mode, control the first electronic control unit, the second electronic control unit, the third electronic control unit, the fourth electronic control unit, and the fifth electronic control unit, so that the third state and the fourth state of the power battery are executed alternately, wherein the third state is: the power battery is discharging and the first battery pack and the second battery pack are charging; and the fourth state is: the power battery is charging and the first battery pack and the second battery pack are discharging.

8. The battery heating system as described in claim 7, characterized in that, The controller is further configured to: in the fourth mode, control the first electric drive system and the third electric drive system to cause the first voltage change of the first battery pack to be ±ΔU1, control the second electric drive system and the fourth electric drive system to cause the second voltage change of the second battery pack to be ±ΔU2, control the fifth electric drive system to cause the third voltage change of the power battery to be ±ΔU3, and the fourth voltage change of the power battery to be ΔU, then ΔU=+ΔU3-ΔU1-ΔU2, or ΔU=-ΔU3+ΔU1+ΔU2, where ΔU<ε, and ε is a preset voltage fluctuation threshold.

9. The battery heating system as described in claim 7, characterized in that, The first electrical control includes a multi-phase first bridge arm, the first bridge arm including a first upper switch and a first lower switch; the second electrical control includes a multi-phase second bridge arm, the second bridge arm including a second upper switch and a second lower switch; the third electrical control includes a multi-phase third bridge arm, the third bridge arm including a third upper switch and a third lower switch; the fourth electrical control includes a multi-phase fourth bridge arm, the multi-phase fourth bridge arm including a fourth upper switch and a fourth lower switch; the fifth electrical control includes a first-phase fifth bridge arm, a second-phase fifth bridge arm, and a third-phase fifth bridge arm, the first-phase fifth bridge arm including a first-phase upper switch and a first-phase lower switch; the second-phase fifth bridge arm including a second-phase upper switch and a second-phase lower switch; and the third-phase fifth bridge arm including a third-phase upper switch and a third-phase lower switch. The controller is used for: In the fourth mode, during the first time period of the control cycle, the first upper switch, the second upper switch, the third lower switch, the fourth lower switch, the first phase upper switch, the second phase lower switch, and the third phase lower switch are controlled to be turned on, and the first lower switch, the second lower switch, the third upper switch, the fourth upper switch, the first phase lower switch, the second phase upper switch, and the third phase upper switch are controlled to be turned off, so that the power battery is charged and the first battery pack and the second battery pack are discharged. In the fourth mode, during the second time period of the control cycle, the first lower switch, the second lower switch, the third upper switch, the fourth upper switch, the first phase lower switch, the second phase upper switch, and the third phase upper switch are controlled to be turned on, and the first upper switch, the second upper switch, the third lower switch, the fourth lower switch, the first phase upper switch, the second phase lower switch, and the third phase lower switch are controlled to be turned off, so that the power battery is discharged and the first battery pack and the second battery pack are charged.

10. The battery heating system as described in claim 6, characterized in that, The controller is also configured to: in the fifth mode, control the fifth electronic control unit to drive the vehicle through the fifth motor, and control the first electronic control unit and the second electronic control unit so that the first state and the second state of the power battery are executed alternately to achieve self-heating of the power battery, wherein the first state is: the first battery pack is discharging and the second battery pack is charging; and the second state is: the first battery pack is charging and the second battery pack is discharging.

11. The battery heating system as described in claim 8, characterized in that, The controller is also configured to: in the sixth mode, control the fifth electronic control unit to drive the vehicle through the fifth motor, and control the first electronic control unit, the second electronic control unit, the third electronic control unit, and the fourth electronic control unit, so that the first state and the second state of the power battery are executed alternately to achieve self-heating of the power battery, wherein the first state is: the first battery pack is discharging and the second battery pack is charging; and the second state is: the first battery pack is charging and the second battery pack is discharging.

12. The battery heating system as described in claim 1, characterized in that, The system also includes: A first switch is disposed between the first N line and the third N line; The second switch is disposed between the second N line and the fourth N line; A first changeover switch, the first end of which is connected to the second bus terminal of the first electronic control and the second bus terminal of the third electronic control respectively, and the second end of which is selectively connected to the negative terminal of the first battery pack and the negative terminal of the second battery pack; The second changeover switch has its first terminal connected to the first bus terminal of the second electronic control unit and the first bus terminal of the fourth electronic control unit, and its second terminal selectively connected to the positive terminal of the first battery pack and the positive terminal of the second battery pack.

13. The battery heating system as described in claim 12, characterized in that, The controller is further configured to: control the first switch and the second switch to be disconnected, control the first changeover switch to be connected to the negative terminal of the second battery pack, control the second changeover switch to be connected to the positive terminal of the first battery pack, and control the first, second, third, and fourth electronic controllers to collaboratively drive the first motor, the second motor, the third motor, and the fourth motor.

14. The battery heating system as described in claim 2, characterized in that, The system also includes: A DC charging port, wherein a first end of the DC charging port is connected to the positive terminal of the first battery pack, and a second end of the DC charging port is connected to the negative terminal of the second battery pack; The controller is further configured to: in the seventh mode, control the first electronic control and the second electronic control, such that the first state and the second state of the power battery are executed alternately to achieve self-heating of the power battery and to charge the power battery through the DC charging port.

15. The battery heating system as described in claim 2, characterized in that, The system also includes: DC charging port; A boost circuit, comprising an inductor and a bridge arm, wherein a first end of the inductor is connected to a first end of the DC charging port, a second end of the inductor is connected to the midpoint of the bridge arm, a first end of the bridge arm is connected to the positive terminal of the first battery pack, and a second end of the bridge arm is connected to the negative terminal of the second battery pack and the second end of the DC charging port; The controller is configured to: in the eighth mode, control the first electronic control unit and the second electronic control unit so that the first state and the second state of the power battery are executed alternately to achieve self-heating of the power battery, and to perform boost charging of the power battery through the DC charging port and the boost circuit.

16. The battery heating system as described in claim 15, characterized in that, The system also includes: The third switch has its first end connected to the first end of the DC charging port, and its second end connected to the first end of the bridge arm and the positive terminal of the first battery pack, respectively. The fourth switch has its first end connected to the first end of the DC charging port and its second end connected to the first end of the inductor. The fifth switch has its first end connected to the second end of the DC charging port, and its second end connected to the second end of the bridge arm and the negative terminal of the second battery pack.

17. The battery heating system as described in claim 15, characterized in that, The bridge arm of the sixth electronic control unit is reused as the bridge arm of the boost circuit, and the inductance of the sixth motor is reused as the inductance of the boost circuit.

18. The battery heating system as described in claim 17, characterized in that, The controller is used to: in the ninth mode, control the first electronic control, the second electronic control, the third electronic control, and the fourth electronic control, so that the first state and the second state of the power battery are executed alternately to realize the self-heating of the power battery, and control the boost circuit to boost the charging of the power battery, wherein the first state is: the first battery pack is discharging and the second battery pack is charging; the second state is: the first battery pack is charging and the second battery pack is discharging.

19. A vehicle, characterized in that, include: The battery heating system as described in any one of claims 1-18.

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