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

Abstract

An embodiment of the present application provides a battery heating device and its control method, control circuit, and power device. The battery heating device includes: a heating module, including a first bridge arm, a second bridge arm, and an energy storage element; and a control module for controlling the first bridge arm and the second bridge arm to form a circuit for the first battery to discharge to the energy storage element, and a circuit for the energy storage element and the first battery to charge to the second battery, and / or to form a circuit for the second battery to discharge to the energy storage element, and a circuit for the energy storage element and the second battery to charge to the first battery, so as to heat the first battery and the second battery. The battery heating device can heat two batteries at the same time, thereby improving heating efficiency.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery heating device, a control method for a battery heating device, a control circuit for a battery heating device, and a power device. Background Art

[0002] Due to its advantages such as high energy density, rechargeable, safe and environmentally friendly, power batteries are widely used in new energy vehicles, consumer electronics, energy storage systems and other fields.

[0003] However, the use of power batteries in low-temperature environments is subject to certain limitations. Specifically, the discharge capacity of power batteries degrades significantly in low-temperature environments, and the batteries cannot be charged in low-temperature environments. Therefore, to ensure normal use of power batteries in low-temperature environments, they need to be heated. Improving the heating efficiency of power batteries has become an urgent problem to be solved. Summary of the Invention

[0004] Embodiments of the present application provide a battery heating device, a control method for a battery heating device, a control circuit for a battery heating device, and a power device, which can improve the heating efficiency of a power battery.

[0005] In a first aspect, a battery heating device is provided, connected to a power battery and configured to heat the power battery. The power battery includes a first battery and a second battery. The battery heating device includes:

[0006] A heating module, comprising a first bridge arm, a second bridge arm and an energy storage element; and

[0007] a control module, configured to control the first bridge arm and the second bridge arm to form a circuit for discharging the first battery to the energy storage element, and a circuit for charging the second battery by the energy storage element and the first battery, and / or to form a circuit for discharging the second battery to the energy storage element, and a circuit for charging the first battery by the energy storage element and the second battery, so as to heat the first battery and the second battery.

[0008] In an embodiment of the present application, a battery heating device can heat two batteries at the same time. The battery heating device includes two bridge arms and an energy storage element. During the discharge and charging process, the two batteries are connected in series. By controlling the two bridge arms, a circuit is formed in which one battery discharges to the energy storage element, and a circuit is formed in which the energy storage element and the battery charge the other battery, thereby heating the two batteries at the same time during the discharge and charging process, with high heating efficiency.

[0009] In a possible implementation, the first end of the first bridge arm is connected to the first end of the first battery, the first end of the second bridge arm is connected to the first end of the second battery, and the second end of the first bridge arm, the second end of the second bridge arm, the second end of the first battery, and the second end of the second battery are connected, wherein the first bridge arm includes a first sub-bridge arm and a second sub-bridge arm, and the second bridge arm includes a third sub-bridge arm and a fourth sub-bridge arm; the first end of the first battery and the first end of the second battery are positive electrodes, and the second end of the first battery and the second end of the second battery are negative electrodes; or, the first end of the first battery and the first end of the second battery are negative electrodes, and the second end of the first battery and the second end of the second battery are positive electrodes.

[0010] In one possible implementation, the first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and the second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or, the first end of the energy storage element is connected to the second end of the first bridge arm, and the second end of the energy storage element is connected to the second end of the second bridge arm.

[0011] In a possible implementation, the control module is specifically configured to:

[0012] Controlling the first sub-bridge arm and the fourth sub-bridge arm to be turned on simultaneously to form a circuit including the first battery, the first sub-bridge arm, the energy storage element, and the fourth sub-bridge arm, so that the first battery discharges the energy storage element; and controlling the first sub-bridge arm and the third sub-bridge arm to be turned on simultaneously to form a circuit including the first battery, the first sub-bridge arm, the energy storage element, the third sub-bridge arm, and the second battery, so that the first battery and the energy storage element charge the second battery; and / or

[0013] The second sub-bridge arm and the third sub-bridge arm are controlled to be turned on at the same time to form a circuit including the second battery, the third sub-bridge arm, the energy storage element and the second sub-bridge arm, so that the second battery discharges to the energy storage element; and the first sub-bridge arm and the third sub-bridge arm are controlled to be turned on at the same time to form a circuit including the second battery, the third sub-bridge arm, the energy storage element, the first sub-bridge arm and the first battery, so that the second battery and the energy storage element charge the first battery.

[0014] In one possible implementation, the first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and the second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or, the first end of the energy storage element is connected to the first end of the first bridge arm, and the second end of the energy storage element is connected to the first end of the second bridge arm.

[0015] In a possible implementation, the control module is specifically configured to:

[0016] Controlling the second sub-bridge arm and the third sub-bridge arm to be turned on simultaneously to form a loop including the first battery, the second sub-bridge arm, the energy storage element, and the third sub-bridge arm, for the first battery to discharge the energy storage element; and controlling the second sub-bridge arm and the fourth sub-bridge arm to be turned on simultaneously to form a loop including the first battery, the second sub-bridge arm, the energy storage element, the fourth sub-bridge arm, and the second battery, for the first battery and the energy storage element to charge the second battery; and / or,

[0017] The first sub-bridge arm and the fourth sub-bridge arm are controlled to be turned on at the same time to form a circuit including the second battery, the fourth sub-bridge arm, the energy storage element and the first sub-bridge arm, so that the second battery discharges to the energy storage element; and the second sub-bridge arm and the fourth sub-bridge arm are controlled to be turned on at the same time to form a circuit including the second battery, the fourth sub-bridge arm, the energy storage element, the second sub-bridge arm and the first battery, so that the second battery and the energy storage element charge the first battery.

[0018] In the above embodiments, by designing a reasonable control sequence to control the conduction and disconnection of each sub-bridge arm, a circuit is formed in which the first battery discharges to the energy storage element, and a circuit in which the energy storage element and the first battery charge the second battery, and / or a circuit in which the second battery discharges to the energy storage element, and a circuit in which the energy storage element and the second battery charge the first battery. By switching back and forth between the discharge and charge circuits, the first and second batteries are repeatedly charged and discharged, heating the first and second batteries during the charge and discharge process.

[0019] In one possible implementation, the first sub-arm includes a first switching transistor, the second sub-arm includes a second switching transistor, the third sub-arm includes a third switching transistor, and the fourth sub-arm includes a fourth switching transistor. The control circuit controls the first switching transistor, the second switching transistor, the third switching transistor, and the fourth switching transistor to respectively turn on and off the first sub-arm, the second sub-arm, the third sub-arm, and the fourth sub-arm.

[0020] In one possible implementation, a state switching switch is connected between the first end of the first battery and the first end of the second battery, or a state switching switch is connected between the second end of the first battery and the second end of the second battery, and the control module is further used to: control the state switching switch to be disconnected so that the first battery and the second battery are connected in series.

[0021] In this embodiment, a state switch is also connected between the two batteries, and the connection between the first battery and the second battery can be switched by the state switch. When the first battery and the second battery are heated, the state switch can be controlled to open, so that the first battery and the second battery are connected in series. In other situations, such as when the first battery and the second battery are supplying power to the power system, the state switch can be controlled to close, so that the first battery and the second battery are connected in parallel.

[0022] In a possible implementation, the energy storage element includes an inductor; or the energy storage element includes an inductor and a first capacitor connected in series.

[0023] In one possible implementation, a second capacitor is connected in parallel across the first battery, and a third capacitor is connected in parallel across the second battery. The second and third capacitors can implement functions such as voltage stabilization to improve the voltage stability of the power battery.

[0024] In a possible implementation, the first battery and the second battery are further connected to a drive circuit of the motor to provide power to the drive circuit.

[0025] In a second aspect, a control method for a battery heating device is provided. The battery heating device is connected to a power battery and is used to heat the power battery. The battery heating device includes a first bridge arm, a second bridge arm, and an energy storage element. The power battery includes a first battery and a second battery. The control method includes:

[0026] The first bridge arm and the second bridge arm are controlled to form a circuit for the first battery to discharge to the energy storage element, and a circuit for the energy storage element and the first battery to charge the second battery, and / or a circuit for the second battery to discharge to the energy storage element, and a circuit for the energy storage element and the second battery to charge the first battery, so as to heat the first battery and the second battery.

[0027] In an embodiment of the present application, two batteries can be heated simultaneously. During the discharge and charging process, the two batteries are connected in series. By designing a reasonable control sequence, the two bridge arms in the battery heating device are controlled to form a circuit in which one battery discharges to the energy storage element, and a circuit in which the energy storage element and the battery charge the other battery, thereby heating the two batteries simultaneously during the discharge and charging process, with high heating efficiency.

[0028] In a possible implementation, the first end of the first bridge arm is connected to the first end of the first battery, the first end of the second bridge arm is connected to the first end of the second battery, and the second end of the first bridge arm, the second end of the second bridge arm, the second end of the first battery, and the second end of the second battery are connected, wherein the first bridge arm includes a first sub-bridge arm and a second sub-bridge arm, and the second bridge arm includes a third sub-bridge arm and a fourth sub-bridge arm; the first end of the first battery and the first end of the second battery are positive electrodes, and the second end of the first battery and the second end of the second battery are negative electrodes; or, the first end of the first battery and the first end of the second battery are negative electrodes, and the second end of the first battery and the second end of the second battery are positive electrodes.

[0029] In one possible implementation, the first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and the second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or, the first end of the energy storage element is connected to the second end of the first bridge arm, and the second end of the energy storage element is connected to the second end of the second bridge arm.

[0030] In a possible implementation, controlling the first bridge arm and the second bridge arm includes: receiving a heating request message; and generating a first control signal according to the heating request message, wherein the first control signal is used to:

[0031] Controlling the first sub-bridge arm and the fourth sub-bridge arm to be turned on simultaneously to form a circuit including the first battery, the first sub-bridge arm, the energy storage element, and the fourth sub-bridge arm, so that the first battery discharges the energy storage element; and controlling the first sub-bridge arm and the third sub-bridge arm to be turned on simultaneously to form a circuit including the first battery, the first sub-bridge arm, the energy storage element, the third sub-bridge arm, and the second battery, so that the first battery and the energy storage element charge the second battery; and / or

[0032] The second sub-bridge arm and the third sub-bridge arm are controlled to be turned on at the same time to form a circuit including the second battery, the third sub-bridge arm, the energy storage element and the second sub-bridge arm, so that the second battery discharges to the energy storage element; and the first sub-bridge arm and the third sub-bridge arm are controlled to be turned on at the same time to form a circuit including the second battery, the third sub-bridge arm, the energy storage element, the first sub-bridge arm and the first battery, so that the second battery and the energy storage element charge the first battery.

[0033] In one possible implementation, the first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and the second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or, the first end of the energy storage element is connected to the first end of the first bridge arm, and the second end of the energy storage element is connected to the first end of the second bridge arm.

[0034] In a possible implementation, controlling the first bridge arm and the second bridge arm includes: receiving a heating request message; and generating a third control signal according to the heating request message, wherein the third control signal is used to:

[0035] Controlling the second sub-bridge arm and the third sub-bridge arm to be turned on simultaneously to form a loop including the first battery, the second sub-bridge arm, the energy storage element, and the third sub-bridge arm, for the first battery to discharge the energy storage element; and controlling the second sub-bridge arm and the fourth sub-bridge arm to be turned on simultaneously to form a loop including the first battery, the second sub-bridge arm, the energy storage element, the fourth sub-bridge arm, and the second battery, for the first battery and the energy storage element to charge the second battery; and / or,

[0036] The first sub-bridge arm and the fourth sub-bridge arm are controlled to be turned on at the same time to form a circuit including the second battery, the fourth sub-bridge arm, the energy storage element and the first sub-bridge arm, so that the second battery discharges to the energy storage element; and the second sub-bridge arm and the fourth sub-bridge arm are controlled to be turned on at the same time to form a circuit including the second battery, the fourth sub-bridge arm, the energy storage element, the second sub-bridge arm and the first battery, so that the second battery and the energy storage element charge the first battery.

[0037] In the above embodiments, by designing a reasonable control sequence to control the conduction and disconnection of each sub-bridge arm, a circuit is formed in which the first battery discharges to the energy storage element, and a circuit in which the energy storage element and the first battery charge the second battery, and / or a circuit in which the second battery discharges to the energy storage element, and a circuit in which the energy storage element and the second battery charge the first battery. By switching back and forth between the discharge and charge circuits, the first and second batteries are repeatedly charged and discharged, heating the first and second batteries during the charge and discharge process.

[0038] In a possible implementation, the control method further includes: receiving a heating stop message; and generating a second control signal according to the heating stop message, wherein the second control signal is used to control the battery heating device to stop heating the power battery.

[0039] In one possible implementation, the first sub-arm includes a first switching transistor, the second sub-arm includes a second switching transistor, the third sub-arm includes a third switching transistor, and the fourth sub-arm includes a fourth switching transistor. The first, second, third, and fourth sub-arms are controlled to turn on and off the first, second, third, and fourth sub-arms, respectively.

[0040] In one possible implementation, a state switching switch is connected between the first end of the first battery and the first end of the second battery, or a state switching switch is connected between the second end of the first battery and the second end of the second battery, and the control method is further used to: control the state switching switch to be disconnected so that the first battery and the second battery are connected in series.

[0041] In a possible implementation, the energy storage element includes an inductor; or the energy storage element includes an inductor and a first capacitor connected in series.

[0042] In one possible implementation, a second capacitor is connected in parallel across the first battery, and a third capacitor is connected in parallel across the second battery. The second and third capacitors can implement functions such as voltage stabilization to improve the voltage stability of the power battery.

[0043] In a possible implementation, the first battery and the second battery are further connected to a drive circuit of the motor to provide power to the drive circuit.

[0044] In a third aspect, a control circuit for a battery heating device is provided, characterized in that it includes a processor, and the processor is used to execute the method in the second aspect or any possible implementation of the second aspect.

[0045] In a fourth aspect, a power device is provided, comprising: a power battery, the power battery comprising a first battery and a second battery; the battery heating device according to the first aspect or any possible implementation of the first aspect, the battery heating device being connected to the power battery and being used to heat the power battery; and a motor, the drive circuit of the motor being connected to the power battery, the power battery being used to provide power to the drive circuit.

[0046] Based on the above technical solution, the battery heating device can heat two batteries at the same time. The battery heating device includes two bridge arms and an energy storage element. During the discharge and charging process, the two batteries are connected in series. By controlling the two bridge arms, a circuit is formed in which one battery discharges to the energy storage element, and a circuit is formed in which the energy storage element and the battery charge the other battery, thereby heating the two batteries simultaneously during the discharge and charging process, with high heating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0048] Figure 1 Schematic diagram of an application scenario of the battery heating device according to an embodiment of the present application.

[0049] Figure 2 Schematic block diagram of a battery heating device according to an embodiment of the present application.

[0050] Figure 3 is based on Figure 2 A schematic diagram of a possible implementation of a battery heating device is shown.

[0051] Figure 4 is based on Figure 2 A schematic diagram of another possible implementation of a battery heating device is shown.

[0052] Figure 5 is based on Figure 2 A schematic diagram of another possible implementation of a battery heating device is shown.

[0053] Figure 6 is based on Figure 2 A schematic diagram of another possible implementation of a battery heating device is shown.

[0054] Figure 7 is a schematic flow chart of a control method for a battery heating device according to an embodiment of the present application.

[0055] Figure 8 4 is a schematic block diagram of a control circuit of a battery heating device according to an embodiment of the present application.

[0056] Figure 9 It is a schematic block diagram of a power device according to an embodiment of the present application. DETAILED DESCRIPTION

[0057] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0058] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0059] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0060] With the development of the times, new energy vehicles have huge market prospects due to their environmental friendliness, low noise, low cost of use and other advantages. They can effectively promote energy conservation and emission reduction, which is beneficial to the development and progress of society.

[0061] Due to the electrochemical characteristics of power batteries, their charge and discharge capabilities are greatly limited in low-temperature environments, seriously affecting customers' winter driving experience. Therefore, in order to ensure normal use of power batteries in low-temperature environments, they need to be heated.

[0062] The power battery in the embodiment of the present application can be a lithium-ion battery, a lithium metal battery, a lead-acid battery, a nickel-cathode battery, a nickel-metal hydride battery, a lithium-sulfur battery, a lithium-air battery or a sodium-ion battery, etc., which are not limited here. In terms of scale, the power battery in the embodiment of the present application can be a single cell, or a battery module or a battery pack, which are not limited here. In terms of application scenarios, the power battery can be used in power devices such as automobiles and ships. For example, it can be applied to power vehicles to power the motors of power vehicles and serve as a power source for electric vehicles. The power battery can also power other electrical devices in electric vehicles, such as in-car air conditioners, car players, etc.

[0063] For the convenience of description, the following will take the application of power batteries in new energy vehicles (i.e., power vehicles, or electric vehicles) as an example to illustrate the solution of this application.

[0064] When a power battery comprises multiple cells, existing technologies typically heat each cell sequentially or connect multiple cells in parallel for simultaneous heating. However, the first approach prolongs the heating time, while the second diverts the heating current. Both approaches result in low heating efficiency, impacting user experience.

[0065] To this end, the present application provides a dual-branch battery heating solution, which enables two batteries to be connected in series through reasonable control, so that both batteries can be heated simultaneously. Since the current used for heating is not shunted, the efficiency of battery heating is improved.

[0066] Figure 1 Schematic diagram showing the application scenario of the battery heating device of the embodiment of the present application. Figure 1 As shown, the battery heating device 110 is connected to the power battery 120, and the battery heating device 110 is used to heat the power battery 120. The power battery 120 includes N batteries, where N is a positive integer greater than or equal to 2, for example Figure 1 The first battery, the second battery, ..., the Nth battery, etc. are shown in . The battery heating device 110 in the embodiment of the present application can heat two of the batteries at a time. That is, the N batteries can be divided into multiple groups, each with two batteries, and the battery heating device 110 heats one group of batteries at a time. The embodiment of the present application does not limit how the N batteries are grouped, nor does it limit the order in which the groups of batteries are heated. Below, taking the first battery and the second battery as an example, how the battery heating device 110 heats the first battery and the second battery at the same time is described.

[0067] In addition, the power battery 120 can also be connected to a power system including a motor, etc. The power battery 120 can be connected to a drive circuit of the motor to provide power to the drive circuit of the motor, thereby allowing the power vehicle equipped with the power battery 120 to travel.

[0068] In one implementation, the battery management system (BMS) of the power battery 120 collects status information of the power battery 120, such as battery temperature, state of charge (SOC), voltage signal, current signal, etc., and determines whether the power battery 120 needs to be heated based on this status information. When it is determined that the power battery 120 needs to be heated, the BMS can send a heating request to the vehicle control unit (VCU). Based on the heating request sent by the BMS, the VCU determines whether to activate the battery heating device 110 to heat the power battery 120.

[0069] For example, after receiving a heating request from the BMS, the VCU can determine whether to use the battery heating device 110 to heat the power battery 120 based on the SOC of the power battery 120. Specifically, when the power battery 120 has sufficient charge, that is, the SOC is high, such as above a threshold, the battery heating device 110 can be used to heat the power battery 120.

[0070] For another example, when the power battery 120 is low in power, that is, when the SOC is low, such as below a threshold, in order to reduce battery heating losses, the battery heating device 110 may not be used to heat the power battery. A motor controller, such as a microprogrammed control unit (MCU), can determine the motor status based on information such as the motor's voltage and current, and send it to the VCU. Therefore, if the motor is in a normal working state at this time, the heat generated by the motor's working losses can be used to heat or keep the power battery 120 warm. For example, the heat generated by the motor's working losses during driving can be used to heat the coolant in the power battery 120, so that the coolant can heat or keep the power battery 120 warm.

[0071] Alternatively, when the SOC of the power battery 120 is low, the battery heating device 110 may be turned on to heat the power battery 120 , and the length of the heating cycle of the battery heating device 110 , or the heating frequency of the battery heating device 110 , may be adjusted.

[0072] The present application does not limit the usage scenario of the battery heating device 110 . The battery heating device 110 in the embodiment of the present application can be used to heat the power battery 120 in any necessary situation.

[0073] While the battery heating device 110 is heating the power battery 120, the battery management system (BMS) of the power battery 120 can also monitor whether the temperature of the power battery 120 is abnormal. If the temperature of the power battery 120 is abnormal, the BMS can send a temperature anomaly message to the VCU, which then controls the battery heating device 110 to stop heating the power battery 120. At this point, the heat generated by the motor's operating losses can be used to heat or maintain the power battery 120. For example, the heat generated by the motor's operating losses can be used to heat the coolant in the power battery 120, thereby allowing the coolant to heat or maintain the power battery 120.

[0074] During the process of the battery heating device 110 heating the power battery 120, if the temperature of the power battery 120 meets the required level, the VCU can control the battery heating device 110 to stop heating the power battery 120. At this time, the heat generated by the motor's operating losses can be used to keep the power battery 120 warm. For example, the heat generated by the motor's operating losses can be used to heat the coolant in the power battery 120, thereby keeping the power battery 120 warm.

[0075] The following, combined Figures 2 to 4 , a scheme for heating the power battery 120 by the battery heating device 110 in an embodiment of the present application is described.

[0076] Figure 2 FIG is a schematic block diagram of the battery heating device 110 according to an embodiment of the present application. Figure 2 As shown, the battery heating device 110 includes a heating module 1110 and a control module 1120. The power battery 120 includes a first battery 121 and a second battery 122. The battery heating device 110 can heat the first battery 121 and the second battery 122 at the same time.

[0077] The heating module 1110 includes a first bridge arm 1111, a second bridge arm 1112, and an energy storage element 1113. The energy storage element 1113 may be, for example, an inductor L, or an inductor L and a first capacitor connected in series.

[0078] For example, a second capacitor C1 may be connected in parallel across the first battery 121, and a third capacitor C2 may be connected in parallel across the second battery 122. The second capacitor C1 and the third capacitor C2 can implement functions such as voltage stabilization, reducing voltage fluctuations between the first battery 121 and the second battery 122 and improving the voltage stability of the first battery 121 and the second battery 122. This reduces the accuracy requirements for battery voltage sampling by the motor controller during driving.

[0079] The control module 1120 is used to: control the first bridge arm 1111 and the second bridge arm 1112 to form a circuit for discharging the first battery 121 to the energy storage element 1113, and a circuit for charging the energy storage element 1113 and the first battery 121 to the second battery 122, so as to heat the first battery 121 and the second battery 122 during the discharging and charging process; and / or control the first bridge arm 1111 and the second bridge arm 1112 to form a circuit for discharging the second battery 122 to the energy storage element 1113, and a circuit for charging the energy storage element 1113 and the second battery 122 to the first battery 121, so as to heat the first battery 121 and the second battery 122 during the discharging and charging process.

[0080] The control module 1120 may be a VCU, or a control module relatively independent of the VCU, for example, a control module specially provided for the battery heating device 110 , which is not limited in the embodiment of the present application.

[0081] As can be seen, when the battery heating device 110 heats the first battery 121 and the second battery 122, the control module 1120 is required to control the first bridge arm 1111 and the second bridge arm 1112 in the heating module 1110. By controlling the conduction or disconnection of the first bridge arm 1111 and the second bridge arm 1112, a circuit is formed in which one of the first battery 121 and the second battery 122 discharges to the energy storage element, and a circuit in which the battery and the energy storage element charge the other battery. The discharge circuit and the charging circuit switch back and forth, and since current flows in both batteries during the discharge and charging processes, the battery temperature increases, achieving simultaneous heating of both batteries with high heating efficiency.

[0082] In one implementation, the first end E11 of the first bridge arm 1111 is connected to the first end of the first battery 121, the first end E21 of the second bridge arm 1112 is connected to the first end of the second battery 122, and the second end E12 of the first bridge arm 1111, the second end E22 of the second bridge arm 1112, the second end of the first battery 121, and the second end of the second battery 122 are connected. The first bridge arm 1111 includes a first sub-bridge arm 1101 and a second sub-bridge arm 1102, and the second bridge arm 1112 includes a third sub-bridge arm 1103 and a fourth sub-bridge arm 1104.

[0083] The first end of the first battery 121 is the positive electrode of the first battery 121, and the second end of the first battery 121 is the negative electrode of the first battery 121. The first end of the second battery 122 is the positive electrode of the second battery 122, and the second end of the second battery 122 is the negative electrode of the second battery 122.

[0084] Alternatively, the first end of the first battery 121 is the negative electrode of the first battery 121, and the second end of the first battery 121 is the positive electrode of the first battery 121. The first end of the second battery 122 is the negative electrode of the second battery 122, and the second end of the second battery 122 is the positive electrode of the second battery 122.

[0085] Furthermore, a state switching switch is connected between the first end E11 of the first battery 121 and the first end E21 of the second battery 122, or a state switching switch is connected between the second end E12 of the first battery 121 and the second end E22 of the second battery 122. Figures 3 to 6 The control module 1120 is further configured to control the state switching switch to be disconnected, so that the first battery 121 and the second battery 122 are connected in series.

[0086] Since the connection between the first battery 121 and the second battery 122 can be switched by a state switch, when the first and second batteries need to be heated, the state switch can be controlled to be open, so that the first and second batteries 121 and 122 are connected in series. In other situations, such as when the first and second batteries 121 and 122 are supplying power to a power system, etc., the state switch can be controlled to be closed, so that the first and second batteries are connected in parallel.

[0087] The serial connection mentioned here may mean that the positive electrode of the first battery 121 is connected to the positive electrode of the second battery 122, and the negative electrode of the first battery 121 is connected to the negative electrode of the second battery 122. In this way, current flows between the first battery 121 and the second battery 122, and energy exchange is achieved between the first battery 121 and the second battery 122.

[0088] The energy storage element 1113 of the present application can be connected between the first bridge arm 1111 and the second bridge arm 1112. For example, Figure 3 and Figure 4 As shown, one end of the energy storage element 1113 is connected between the first sub-bridge arm 1101 and the second sub-bridge arm 1102 , and the other end of the energy storage element 1113 is connected between the third sub-bridge arm 1103 and the fourth sub-bridge arm 1104 .

[0089] For example, Figure 5 As shown, one end of the energy storage element 1113 is connected to the second end E12 of the first bridge arm 1111 , and the other end of the energy storage element 1113 is connected to the second end E22 of the second bridge arm 1112 .

[0090] For example, Figure 6 As shown, one end of the energy storage element 1113 is connected to the first end E11 of the first bridge arm 1111 , and the other end of the energy storage element 1113 is connected to the first end E21 of the second bridge arm 1112 .

[0091] In one implementation, for Figures 3 to 5 The heating module 1110 shown, when heating the first battery 121 and the second battery 122 connected in series, the control module 1120 can control the first sub-bridge arm 1101 and the fourth sub-bridge arm 1104 to be turned on at the same time, forming a circuit including the first battery 121, the first sub-bridge arm 1101, the energy storage element 1113 and the fourth sub-bridge arm 1104, for the first battery 121 to discharge the energy storage element 1113; and control the first sub-bridge arm 1101 and the third sub-bridge arm 1103 to be turned on at the same time, forming a circuit including the first battery 121, the first sub-bridge arm 1101, the energy storage element L, the third sub-bridge arm 1103 and the second battery 122, for the first battery 121 and the energy storage element 1113 to charge the second battery 122.

[0092] Or, for Figures 3 to 5 The heating module 1110 shown, when heating the first battery 121 and the second battery 122 connected in series, the control module 1120 can also control the second sub-bridge arm 1102 and the third sub-bridge arm 1103 to be turned on at the same time, forming a circuit including the second battery 122, the third sub-bridge arm 1103, the energy storage element 1113 and the second sub-bridge arm 1102, for the second battery 122 to discharge the energy storage element 1113; and control the first sub-bridge arm 1101 and the third sub-bridge arm 1103 to be turned on at the same time, forming a circuit including the second battery 122, the third sub-bridge arm 1103, the energy storage element 1113, the first sub-bridge arm 1101 and the first battery 121, for the second battery 122 and the energy storage element 1113 to charge the first battery 121.

[0093] The following, combined Figures 3 to 5 The battery heating process is described in detail by taking the first end of the first battery 121 as the positive electrode of the first battery 121, the second end of the first battery 121 as the negative electrode of the first battery 121, the first end of the second battery 122 as the positive electrode of the second battery 122, the second end of the second battery 122 as the negative electrode of the second battery 122, and the energy storage element 1113 as the inductor L as an example.

[0094] In one implementation, Figures 3 to 5 In the illustrated heating module 1110, the first sub-bridge arm 1101 includes a first switching transistor V11, the second sub-bridge arm 1102 includes a second switching transistor V12, the third sub-bridge arm 1103 includes a third switching transistor V13, and the fourth sub-bridge arm 1104 includes a fourth switching transistor V14. The control circuit 1120 controls the first switching transistor V11, the second switching transistor V12, the third switching transistor V13, and the fourth switching transistor V14 to respectively turn on the first sub-bridge arm 1101, the second sub-bridge arm 1102, the third sub-bridge arm 1103, and the fourth sub-bridge arm 1104.

[0095] Specifically, in one implementation, for Figures 3 to 5 The heating module 1110 shown in the figure can include a first stage and a second stage in each heating cycle. In the first stage, the first switch tube V11 and the fourth switch tube V14 are closed, and the second switch tube V12 and the third switch tube V13 are opened, forming a loop including the first battery 121, the first switch tube V11, the inductor L and the fourth switch tube V14. The loop is used for discharging the first battery 121 and storing energy in the inductor L. The discharge path of the first battery 121 to the inductor L is: the positive electrode of the first battery 121 → V11 → L → V14 → the negative electrode of the first battery 121; in the second stage, the first switch tube V11 is closed, and the second switch tube V12 is closed. The third switch V11 and the third switch V13 are closed, while the second switch V12 and the fourth switch V14 are opened, forming a circuit including the first battery 121, the first switch V11, the inductor L, the third switch V13, and the second battery 122. This circuit is used for the first battery 121 and the inductor L to charge the second battery 122. The charging path is: positive electrode of the first battery 121 → V11 → L → V13 → positive electrode of the second battery 122 → negative electrode of the second battery 122 → negative electrode of the first battery 121. Furthermore, to maintain this state, the charging time for the second battery 122 can be controlled by repeatedly switching the third switch V13 and the fourth switch V14.

[0096] Furthermore, each heating cycle may include not only the first and second stages, but also the third and fourth stages. In the third stage, the second switch tube V12 and the third switch tube V13 are closed, and the first switch tube V11 and the fourth switch tube V14 are disconnected, forming a loop including the second battery 122, the third switch tube V13, the inductor L, and the second switch tube V12. This loop is used for discharging the second battery 122 and storing energy in the inductor L. The discharge path of the second battery 122 to the inductor L is: the positive electrode of the second battery 122 → V13 → L → V12 → the negative electrode of the second battery 122; in the fourth stage, the first switch tube V11 is closed, and the fourth switch tube V14 is disconnected. The first and second switching transistors V11 and V13 are closed, while the second and fourth switching transistors V12 and V14 are opened, forming a circuit including the second battery 122, the third switching transistor V13, the inductor L, the first switching transistor V11, and the first battery 121. This circuit is used for the second battery 122 and the inductor L to charge the first battery 121. The charging path is: positive electrode of the second battery 122 → V13 → L → V11 → positive electrode of the first battery 121 → negative electrode of the first battery 121 → negative electrode of the second battery 122. Furthermore, to maintain this state, the charging time for the first battery 121 can be controlled by repeatedly switching the first and second switching transistors V11 and V12.

[0097] Similarly, in another implementation, for Figure 3 、 Figure 4 and Figure 6 The heating module 1110 shown in FIG. 11 shows a heating module 1110. When heating the first battery 121 and the second battery 122 connected in series, in the first stage, the control module 1120 can control the second sub-bridge arm 1102 and the third sub-bridge arm 1103 to be turned on at the same time, forming a circuit including the first battery 121, the second sub-bridge arm 1102, the energy storage element 1113 and the third sub-bridge arm 1103, for the first battery 121 to discharge to the energy storage element 1113; in the second stage, the second sub-bridge arm 1102 and the fourth sub-bridge arm 1104 are controlled to be turned on at the same time, forming a circuit including the first battery 121, the second sub-bridge arm 1102, the energy storage element L, the fourth sub-bridge arm 1104 and the second battery 122, for the first battery 121 and the storage element L. The energy storage element 1113 charges the second battery 122; in the third stage, the control module 1120 can also control the first sub-bridge arm 1101 and the fourth sub-bridge arm 1104 to be turned on at the same time, forming a circuit including the second battery 122, the fourth sub-bridge arm 1104, the energy storage element 1113 and the first sub-bridge arm 1101, for the second battery 122 to discharge the energy storage element 1113; in the fourth stage, the second sub-bridge arm 1102 and the fourth sub-bridge arm 1104 are controlled to be turned on at the same time, forming a circuit including the second battery 122, the fourth sub-bridge arm 1104, the energy storage element 1113, the second sub-bridge arm 1102 and the first battery 121, for the second battery 122 and the energy storage element 1113 to charge the first battery 121. In particular, the control module 1120 can realize the conduction and disconnection of each sub-bridge arm by controlling the switch tube on each sub-bridge arm.

[0098] It can be seen that according to the specific circuit structure of the heating module 1110, by designing a reasonable control sequence, the control Figures 3 to 6 The conduction and disconnection of each sub-bridge arm in the heating module 1110 shown form a circuit in which one battery discharges to the energy storage element 1113, and a circuit in which the energy storage element 1113 and the battery charge the other battery. The discharge circuit and the charging circuit switch back and forth, thereby heating the two batteries simultaneously during the discharge and charging process, with high heating efficiency.

[0099] It should be understood that Figure 3 The heating module 1110 shown is only for illustration, and each sub-bridge arm may also have other implementations. Figure 4In a more preferred implementation shown in FIG, the first sub-bridge arm 1101 may include a first switch tube V11 and a first freewheeling diode D11 connected in parallel with the first switch tube V11; the second sub-bridge arm 1102 may include a second switch tube V12 and a second freewheeling diode D12 connected in parallel with the second switch tube V12; the third sub-bridge arm 1103 may include a third switch tube V13 and a third freewheeling diode D13 connected in parallel with the third switch tube V13; the fourth sub-bridge arm 1104 may include a fourth switch tube V14 and a fourth freewheeling diode D14 connected in parallel with the fourth switch tube V14.

[0100] Freewheeling diodes are often used in conjunction with inductors. When the current in an inductor changes suddenly, the voltage across the inductor can change dramatically, potentially damaging other components in the circuit. However, when used with a freewheeling diode, the inductor's current changes more smoothly, preventing sudden voltage changes and improving circuit safety.

[0101] For example, if Figure 4 As shown, when entering the second stage from the first stage of a heating cycle, that is, when the third switch tube V13 and the fourth switch tube V14 are switched, due to the switching delay, the current may briefly remain in the discharge path of the first battery 121 to the inductor L in the first stage. At this time, the fourth freewheeling diode D14 can buffer the current to avoid sudden voltage changes and improve the safety of the circuit.

[0102] It should be understood that in some cases, the first switch tube V11 and the first freewheeling diode connected in parallel therewith, the second switch tube V12 and the second freewheeling diode D12 connected in parallel therewith, the third switch tube V13 and the third freewheeling diode connected in parallel therewith, and the fourth switch tube V14 and the fourth freewheeling diode D14 connected in parallel therewith can all be referred to as insulated gate bipolar translators (IGBTs).

[0103] Similarly, for Figure 5 and Figure 6 In the heating module 1110 shown, each sub-bridge arm may also include a switch tube and a freewheeling diode connected in parallel with the switch tube, which are not shown in this application.

[0104] The embodiment of the present application does not limit the specific form of each sub-bridge arm. When each sub-bridge arm does not include a freewheeling diode, the function of the battery heating module 1110 can still be realized.

[0105] The “connection” or “connected” described in the embodiments of the present application may be a direct connection or an indirect connection through other elements, and the present application does not limit this.

[0106] The present application also provides a method for controlling a battery heating device. Here, the structure of the battery heating device can refer to the above Figures 1 to 6 The detailed description of is not repeated here. Figure 7 As shown, the control method 700 of the battery heating device includes some or all of the following steps.

[0107] In step 710, the first bridge arm and the second bridge arm are controlled to form a circuit in which the first battery discharges to the energy storage element, and a circuit in which the energy storage element and the first battery charge the second battery, so as to heat the first battery and the second battery. And / or,

[0108] In step 720, the first bridge arm and the second bridge arm are controlled to form a circuit for the second battery to discharge to the energy storage element, and a circuit for the energy storage element and the second battery to charge the first battery, so as to heat the first battery and the second battery.

[0109] Based on the above technical solution, two batteries can be heated simultaneously. During the discharge and charging process, the two batteries are connected in series. By designing a reasonable control sequence, the two bridge arms in the battery heating device are controlled to form a circuit in which one battery discharges to the energy storage element, and a circuit in which the energy storage element and the battery charge the other battery. In this way, the two batteries can be heated simultaneously during the discharge and charging process, with high heating efficiency.

[0110] In one implementation, the first end of the first bridge arm is connected to the first end of the first battery, the first end of the second bridge arm is connected to the first end of the second battery, and the second end of the first bridge arm, the second end of the second bridge arm, the second end of the first battery, and the second end of the second battery are connected, wherein the first bridge arm includes a first sub-bridge arm and a second sub-bridge arm, and the second bridge arm includes a third sub-bridge arm and a fourth sub-bridge arm; the first end of the first battery and the first end of the second battery are positive electrodes, and the second end of the first battery and the second end of the second battery are negative electrodes; or, the first end of the first battery and the first end of the second battery are negative electrodes, and the second end of the first battery and the second end of the second battery are positive electrodes.

[0111] In one possible implementation, the first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and the second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or, the first end of the energy storage element is connected to the second end of the first bridge arm, and the second end of the energy storage element is connected to the second end of the second bridge arm.

[0112] In one possible implementation, in step 710, controlling the first bridge arm and the second bridge arm includes: receiving a heating request message; generating a first control signal according to 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 turned on at the same time, forming a loop including the first battery, the first sub-bridge arm, the energy storage element and the fourth sub-bridge arm, for the first battery to discharge the energy storage element; and controlling the first sub-bridge arm and the third sub-bridge arm to be turned on at the same time, forming a loop including the first battery, the first sub-bridge arm, the energy storage element, the third sub-bridge arm and the second battery, for the first battery and the energy storage element to charge the second battery.

[0113] In one possible implementation, in step 720, controlling the first bridge arm and the second bridge arm includes: receiving a heating request message; generating a first control signal according to the heating request message, wherein the first control signal is used to: control the second sub-bridge arm and the third sub-bridge arm to be turned on at the same time, forming a loop including the second battery, the third sub-bridge arm, the energy storage element and the second sub-bridge arm, for the second battery to discharge the energy storage element; and controlling the first sub-bridge arm and the third sub-bridge arm to be turned on at the same time, forming a loop including the second battery, the third sub-bridge arm, the energy storage element, the first sub-bridge arm and the first battery, for the second battery and the energy storage element to charge the first battery.

[0114] In one possible implementation, the first end of the energy storage element is connected between the first sub-bridge arm and the second sub-bridge arm, and the second end of the energy storage element is connected between the third sub-bridge arm and the fourth sub-bridge arm; or, the first end of the energy storage element is connected to the first end of the first bridge arm, and the second end of the energy storage element is connected to the first end of the second bridge arm.

[0115] In one possible implementation, in step 710, controlling the first bridge arm and the second bridge arm includes: receiving a heating request message; generating a third control signal according to 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 turned on at the same time, forming a loop including the first battery, the second sub-bridge arm, the energy storage element and the third sub-bridge arm, for the first battery to discharge the energy storage element; and controlling the second sub-bridge arm and the fourth sub-bridge arm to be turned on at the same time, forming a loop including the first battery, the second sub-bridge arm, the energy storage element, the fourth sub-bridge arm and the second battery, for the first battery and the energy storage element to charge the second battery.

[0116] In one possible implementation, in step 720, controlling the first bridge arm and the second bridge arm includes: receiving a heating request message; generating a third control signal according to the heating request message, wherein the third control signal is used to: control the first sub-bridge arm and the fourth sub-bridge arm to be turned on at the same time, forming a loop including the second battery, the fourth sub-bridge arm, the energy storage element and the first sub-bridge arm, for the second battery to discharge the energy storage element; and controlling the second sub-bridge arm and the fourth sub-bridge arm to be turned on at the same time, forming a loop including the second battery, the fourth sub-bridge arm, the energy storage element, the second sub-bridge arm and the first battery, for the second battery and the energy storage element to charge the first battery.

[0117] In a possible implementation, the control method further includes: receiving a heating stop message; and generating a second control signal according to the heating stop message, wherein the second control signal is used to control the battery heating device to stop heating the power battery.

[0118] In one implementation, the first sub-arm includes a first switching transistor, the second sub-arm includes a second switching transistor, the third sub-arm includes a third switching transistor, and the fourth sub-arm includes a fourth switching transistor. The first, second, third, and fourth sub-arms are controlled to turn on and off the first, second, third, and fourth sub-arms, respectively.

[0119] In one implementation, a state switching switch is connected between the first end of the first battery and the first end of the second battery, or a state switching switch is connected between the second end of the first battery and the second end of the second battery, and the control method is further used to: control the state switching switch to be disconnected so that the first battery and the second battery are connected in series.

[0120] In one implementation, the energy storage element includes an inductor; or, the energy storage element includes an inductor and a first capacitor connected in series.

[0121] In one implementation, a second capacitor is connected in parallel across both ends of the first battery, and a third capacitor is connected in parallel across both ends of the second battery.

[0122] In one implementation, the first battery and the second battery are further connected to a drive circuit of the motor to provide power to the drive circuit.

[0123] It should be understood that the specific control of each bridge arm and the beneficial effects produced in the method embodiment can refer to the corresponding description in the above device embodiment, and for the sake of brevity, it will not be repeated here.

[0124] Figure 8 FIG. 8 is a schematic block diagram of a control circuit 800 of a battery heating device according to an embodiment of the present application. Figure 8 As shown, the control circuit 800 includes a processor 820. Optionally, the control circuit 800 also includes a memory 810, wherein the memory 810 is used to store instructions, and the processor 820 is used to read the instructions and execute the methods in the above-mentioned various embodiments of the present application based on the instructions.

[0125] The processor 820 may correspond to, for example, a control module of any of the aforementioned battery heating devices.

[0126] Figure 9 A schematic block diagram of a power device 900 according to an embodiment of the present application is shown. The power device 900 includes: a power battery 120; a battery heating device 110 according to any of the above embodiments, connected to the power battery 120 for heating the power battery 120; and a motor 130, whose drive circuit 131 is connected to the power battery 120 for providing power to the drive circuit 131.

[0127] The power plant 900 may be, for example, a powered vehicle.

[0128] An embodiment of the present application further provides a readable storage medium for storing a computer program, which is used to execute the methods in the above-mentioned embodiments of the present application.

[0129] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0130] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, devices and units can refer to the corresponding processes in the above-described method embodiments and will not be repeated here.

[0131] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0132] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

Claims

1. A battery heating device, characterized in that: Connected to a power battery and used to heat the power battery, the power battery including a first battery and a second battery, the battery heating device including: 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 the first battery to discharge the energy storage element, and a circuit for the energy storage element and the first battery to charge the second battery, and / or to form a circuit for the second battery to discharge the energy storage element, and a circuit for the energy storage element and the second battery to charge the first battery, so as to heat the first battery and the second battery; The first end of the first bridge arm is connected to the first end of the first battery, the first end of the second bridge arm is connected to the first end of the second battery, and the second end of the first bridge arm, the second end of the second bridge arm, the second end of the first battery, and the second end of the second battery are connected, wherein the first bridge arm includes a first sub-bridge arm and a second sub-bridge arm, and the second bridge arm includes a third sub-bridge arm and a fourth sub-bridge arm; the first end of the first battery is the positive electrode of the first battery, the second end of the first battery is the negative electrode of the first battery, the first end of the second battery is the positive electrode of the second battery, and the second end of the second battery is the negative electrode of the second battery; or, the first end of the first battery is the negative electrode of the first battery, the second end of the first battery is the positive electrode of the first battery, the first end of the second battery is the negative electrode of the second battery, and the second end of the second battery is the positive electrode of the second battery; The first end of the energy storage element is connected to the second end of the first bridge arm, and the second end of the energy storage element is connected to the second end of the second bridge arm; or the first end of the energy storage element is connected to the first end of the first bridge arm, and the second end of the energy storage element is connected to the first end of the second bridge arm; A state switching switch is connected between the first end of the first battery and the first end of the second battery, or a state switching switch is connected between the second end of the first battery and the second end of the second battery, and the control module is further used to control the state switching switch to be disconnected so that the first battery and the second battery are connected in series.

2. The battery heating device according to claim 1, characterized in that: The control module is specifically used for: controlling the second sub-bridge arm and the third sub-bridge arm to be turned on simultaneously to form a loop including the first battery, the second sub-bridge arm, the energy storage element, and the third sub-bridge arm, so that the first battery discharges the energy storage element; controlling the second sub-bridge arm and the fourth sub-bridge arm to be turned on simultaneously to form a loop including the first battery, the second sub-bridge arm, the energy storage element, the fourth sub-bridge arm, and the second battery, so that the first battery and the energy storage element charge the second battery; and / or, controlling the first sub-bridge arm and the fourth sub-bridge arm to be turned on simultaneously to form a loop including the second battery, the fourth sub-bridge arm, the energy storage element, and the first sub-bridge arm, so that the second battery discharges into the energy storage element; The second sub-bridge arm and the fourth sub-bridge arm are controlled to be turned on simultaneously to form a loop including the second battery, the fourth sub-bridge arm, the energy storage element, the second sub-bridge arm and the first battery, so that the second battery and the energy storage element can charge the first battery.

3. The battery heating device according to any one of claims 1 to 2, characterized in that: The first sub-bridge arm includes a first switching tube, the second sub-bridge arm includes a second switching tube, the third sub-bridge arm includes a third switching tube, and the fourth sub-bridge arm includes a fourth switching tube. The control module controls the first switch tube, the second switch tube, the third switch tube and the fourth switch tube to respectively turn on and off the first sub-bridge arm, the second sub-bridge arm, the third sub-bridge arm and the fourth sub-bridge arm.

4. The battery heating device according to any one of claims 1 to 2, characterized in that: The energy storage element includes an inductor.

5. The battery heating device according to any one of claims 1 to 2, characterized in that: A second capacitor is connected in parallel to both ends of the first battery, and a third capacitor is connected in parallel to both ends of the second battery.

6. A control method for a battery heating device, characterized in that: The battery heating device is connected to the power battery and is used to heat the power battery. The battery heating device includes a first bridge arm, a second bridge arm, and an energy storage element. The power battery includes a first battery and a second battery. The control method includes: controlling the first bridge arm and the second bridge arm to form a circuit in which the first battery discharges to the energy storage element, and a circuit in which the energy storage element and the first battery charge the second battery, and / or forming a circuit in which the second battery discharges to the energy storage element, and a circuit in which the energy storage element and the second battery charge the first battery, so as to heat the first battery and the second battery; The first end of the first bridge arm is connected to the first end of the first battery, the first end of the second bridge arm is connected to the first end of the second battery, and the second end of the first bridge arm, the second end of the second bridge arm, the second end of the first battery, and the second end of the second battery are connected, wherein the first bridge arm includes a first sub-bridge arm and a second sub-bridge arm, and the second bridge arm includes a third sub-bridge arm and a fourth sub-bridge arm; The first end of the first battery and the first end of the second battery are positive electrodes, and the second end of the first battery and the second end of the second battery are negative electrodes; or the first end of the first battery and the first end of the second battery are negative electrodes, and the second end of the first battery and the second end of the second battery are positive electrodes; The first end of the energy storage element is connected to the second end of the first bridge arm, and the second end of the energy storage element is connected to the second end of the second bridge arm; or the first end of the energy storage element is connected to the first end of the first bridge arm, and the second end of the energy storage element is connected to the first end of the second bridge arm; A state switching switch is connected between the first end of the first battery and the first end of the second battery, or a state switching switch is connected between the second end of the first battery and the second end of the second battery. The control method is further used to control the state switching switch to be disconnected so that the first battery and the second battery are connected in series.

7. The control method according to claim 6, characterized in that: The controlling the first bridge arm and the second bridge arm includes: receiving a heating request message; Generate a third control signal according to the heating request message, wherein the third control signal is used to: controlling the second sub-bridge arm and the third sub-bridge arm to be turned on simultaneously to form a loop including the first battery, the second sub-bridge arm, the energy storage element, and the third sub-bridge arm, so that the first battery discharges the energy storage element; controlling the second sub-bridge arm and the fourth sub-bridge arm to be turned on simultaneously to form a loop including the first battery, the second sub-bridge arm, the energy storage element, the fourth sub-bridge arm, and the second battery, so that the first battery and the energy storage element charge the second battery; and / or, controlling the first sub-bridge arm and the fourth sub-bridge arm to be turned on simultaneously to form a loop including the second battery, the fourth sub-bridge arm, the energy storage element, and the first sub-bridge arm, so that the second battery discharges into the energy storage element; The second sub-bridge arm and the fourth sub-bridge arm are controlled to be turned on simultaneously to form a loop including the second battery, the fourth sub-bridge arm, the energy storage element, the second sub-bridge arm and the first battery, so that the second battery and the energy storage element can charge the first battery.

8. The control method according to claim 6, characterized in that: The control method further includes: Receive heating stop message; A second control signal is generated according to the heating stop message, wherein the second control signal is used to control the battery heating device to stop heating the power battery.

9. The control method according to claim 6, characterized in that: The first sub-bridge arm includes a first switching tube, the second sub-bridge arm includes a second switching tube, the third sub-bridge arm includes a third switching tube, and the fourth sub-bridge arm includes a fourth switching tube. The first, second, third and fourth sub-bridge arms are controlled to be turned on and off respectively.

10. The control method according to claim 6, characterized in that: The energy storage element includes an inductor.

11. The control method according to claim 6, characterized in that: A second capacitor is connected in parallel to both ends of the first battery, and a third capacitor is connected in parallel to both ends of the second battery.

12. The control method according to any one of claims 6 to 11, characterized in that: The first battery and the second battery are also connected to the driving circuit of the motor to provide power to the driving circuit.

13. A power device, characterized in that: include: A power battery, comprising a first battery and a second battery; The battery heating device according to any one of claims 1 to 5, connected to the power battery, for heating the power battery; as well as, A motor, wherein the drive circuit of the motor is connected to the power battery, and the power battery is used to provide power to the drive circuit.

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