Apparatus and method for battery heating

Abstract

Embodiments of the present application provide a device and method for battery heating. The device is arranged in a first power consuming device, and comprises: a first interface electrically coupled to a neutral point of a motor winding of the first power consuming device; a second interface electrically coupled to a negative pole of a battery of the first power consuming device; and a control module coupled to control systems of the first power consuming device and a second power consuming device to coordinate control of the first power consuming device and the second power consuming device; wherein: the first interface is configured to be engageable with a third interface electrically coupled to a neutral point of a motor winding of the second power consuming device; the second interface is configured to be engageable with a fourth interface electrically coupled to a negative pole of a battery of the second power consuming device; and the control module is configured to perform a battery heating step.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a device and method for battery heating. BACKGROUND

[0002] Due to the advantages of high energy density, recyclable charging, safety and environmental protection, batteries are widely used in the fields of transportation tools, consumer electronics, energy storage systems, etc. SUMMARY

[0003] The present application provides a device and method for battery heating, which can solve the self-heating problem of the battery under low temperature conditions through battery charging and discharging.

[0004] According to a first aspect of the present application, a device for battery heating is provided, the device is arranged in a first electric device, and comprises: a first interface electrically coupled to the neutral point of the motor winding of the first electric device; a second interface electrically coupled to the negative electrode of the battery of the first electric device; and a control module coupled to the control systems of the first electric device and a second electric device to coordinate the control of the first electric device and the second electric device; wherein: the first interface is configured to be engaged with a third interface electrically coupled to the neutral point of the motor winding of the second electric device; the second interface is configured to be engaged with a fourth interface electrically coupled to the negative electrode of the battery of the second electric device; and the control module is configured to perform a battery heating step.

[0005] According to a second aspect of the present application, a device for battery heating is provided, the device is arranged in a charging pile, and comprises: a first switch coupled in series between a first charging gun and a second charging gun of the charging pile, wherein the first charging gun is configured to be engaged with a first charging socket of a first electric device, the first charging socket is electrically coupled to the neutral point of the motor winding of the first electric device, the second charging gun is configured to be engaged with a second charging socket of a second electric device, the second charging socket is electrically coupled to the neutral point of the motor winding of the second electric device; and a control module coupled to the control systems of the first electric device and the second electric device to coordinate the control of the first electric device, the second electric device and the charging pile; wherein: the first switch is configured to be closed to electrically couple the neutral point of the motor winding of the first electric device to the neutral point of the motor winding of the second electric device electrically coupled to the second electric device; the control module is configured to perform a battery heating step.

[0006] According to a third aspect of the present application, a method for battery heating is provided, the method is performed at a power consuming device or a charging pile, and comprises: engaging a first interface electrically coupled to a neutral point of a motor winding of a first power consuming device to a third interface electrically coupled to a neutral point of a motor winding of a second power consuming device; engaging a second interface electrically coupled to a negative electrode of a battery of the first power consuming device to a fourth interface electrically coupled to a negative electrode of a battery of the second power consuming device; and performing a battery heating step. BRIEF DESCRIPTION OF DRAWINGS

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by the drawings without creative labor.

[0008] Figure 1 is a structural schematic diagram of at least a part of a system for battery heating disclosed by an embodiment of the present application;

[0009] Figure 2 is a structural schematic diagram of a system for battery heating disclosed by an embodiment of the present application;

[0010] Figure 3 is a flowchart of a method for battery heating disclosed by an embodiment of the present application;

[0011] In the drawings, the drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0012] The embodiments of the present application will be further described in detail below with reference to the drawings and embodiments. The detailed description of the following embodiments and the drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0013] In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "a plurality of" is more than two; the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer" and the like is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0014] In the description of the application, it also needs to be explained that when a component is referred to as "connected", "coupled" or "joined" to another component, it can be directly connected, coupled or joined to the other component, or there can be an intermediate component. In contrast, when a component is referred to as "directly connected", "directly coupled" or "directly joined" to another component, there can be no intermediate component. Other words used to describe the relationship between elements (for example, "between" and "directly between", etc.) should be interpreted in a similar manner.

[0015] Unless specifically stated and otherwise clearly limited, the singular forms "a", "an" and "the" are intended to include plural forms as well. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including", when used herein, specify the presence of stated features, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and / or groups thereof.

[0016] Batteries generally need to operate within a suitable operating temperature range, and low temperature environments can adversely affect the normal use of batteries. For example, in a low temperature environment, the capacity of a battery can be severely degraded, and normal charging and discharging cannot be performed. Therefore, in order to be able to normally use the battery, the battery needs to be heated in a low temperature environment.

[0017] The electrical system of some electrical devices (such as electric vehicles) often includes, in addition to the battery, devices such as motors that utilize the electrical energy stored in the battery, and control devices such as power converters that supply power to the motor using the battery. Therefore, in the case where the battery in the electrical device needs to be heated on the basis of the original components of the electrical device, it is necessary to avoid excessive modification or damage to these original components. For example, in the case where the electrical device adopts a multi-phase system (such as a three-phase motor and a three-phase power converter), for the battery heating problem, the prior art often controls the motor in the electrical device to adopt 0 torque to heat the battery, which has a low heating rate, and due to the imbalance between the phases of the motor, can cause vibration and noise problems of the motor, and can cause mechanical and electrical damage.

[0018] Therefore, in the process of heating the battery, the balance between the phases should be considered, so as to avoid, for example, the vibration and noise problems of the motor due to the imbalance between the phases, thereby causing mechanical and electrical damage to the motor.

[0019] Based on the above considerations, the inventors propose a system and a method for battery heating, by leading out the neutral points of the multi-phase windings of the electric machines of the electric devices, so that the multi-phase windings of the electric machines are equivalent in parallel, thereby increasing the current flowing through the batteries of the electric devices to achieve fast heating, and ensuring the multi-phase balance of the electric devices during battery heating; in addition, the neutral points of the multi-phase windings of the electric machines of a plurality of electric devices are connected, so that the batteries of these electric devices can charge and discharge each other, improving the heating efficiency.

[0020] The electric device in the embodiments of the present application can be a pure electric vehicle, a hybrid electric vehicle, an electric vehicle, etc., but is not limited thereto, and can be any electric device including a multi-phase electric machine and powered by a battery.

[0021] The application scenarios of the device and the method according to the present application can include rescue vehicles rescuing one or more vehicles that cannot start due to low-temperature batteries, charging piles enabling low-temperature fast heating and charging between two or more vehicles through the charging piles, etc.

[0022] Figure 1 is a structural schematic diagram of at least a part of a system 100 for battery heating according to an embodiment of the present application. The system 100 is suitable for the case of directly performing battery heating between two electric devices. As shown in Figure 1 The system 100 includes an electric device 1 and an electric device 2. As a non-limiting example, the electric device 1 can be a rescue vehicle, and the electric device 2 can be a rescued vehicle that needs to perform battery heating due to low temperature. The electric device 1 includes a battery 111, an electric machine 112, and a three-phase power converter 113 coupled between the battery 111 and the electric machine 112; the electric device 2 includes a battery 121, an electric machine 122, and a three-phase power converter 123 coupled between the battery 121 and the electric machine 122. Figure 1 The electric machines 112 and 122 shown in are three-phase electric machines with three-phase windings, but it should be understood that the embodiments of the present application are not limited thereto, and the electric machines 112 and 122 can be three-phase electric machines, six-phase electric machines, nine-phase electric machines, etc., and the electric machine windings of the electric machines 112 and 122 correspondingly have three-phase inductance, six-phase inductance, nine-phase inductance, etc. Figure 1 The topologies of the three-phase power converters 113 and 123 shown in are the topologies of conventional AC / DC converters, which include three parallel coupled bridge arms for three phases respectively, wherein each bridge arm includes a series coupled upper bridge arm switch and a lower bridge arm switch. As shown in Figure 1Taking the three-phase power converter 113 as an example, it includes an upper-arm switch V11 and a lower-arm switch V14 for the first phase, an upper-arm switch V12 and a lower-arm switch V15 for the second phase, and an upper-arm switch V13 and a lower-arm switch V16 for the third phase. It also includes a freewheeling diode D11 coupled in parallel with switch V11, a freewheeling diode D12 coupled in parallel with switch V12, a freewheeling diode D13 coupled in parallel with switch V13, a freewheeling diode D14 coupled in parallel with switch V14, a freewheeling diode D15 coupled in parallel with switch V15, and a freewheeling diode D16 coupled in parallel with switch V16. However, it should be understood that other converter topologies can also be adopted. These switches can be one or more power switching devices such as Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) and Insulated-Gate Bipolar Transistors (IGBTs).

[0023] like Figure 1 As shown, system 100 may include an interface 116 electrically coupled to the neutral point of the windings of motor 112 and an interface 115 electrically coupled to the negative terminal of battery 111 for electrical device 1, and an interface 126 electrically coupled to the neutral point of the windings of motor 122 and an interface 125 electrically coupled to the negative terminal of battery 121 for electrical device 2. Interface 116 may engage with interface 126 and interface 115 may engage with interface 125 to electrically couple electrical device 1 and electrical device 2 together. Furthermore, system 100 may also include a control module 117 disposed in electrical device 1, which is coupled to the control system of electrical device 1 and electrical device 2 for coordinated control of power converters and other switches in electrical device 1 and electrical device 2. Although not shown, similarly, a control module may also be disposed in electrical device 2.

[0024] In embodiments according to this application, system 100 may include a switch K116 series coupled between the neutral point of the windings of motor 112 and interface 116. Additionally, system 100 may include a switch K126 series coupled between the neutral point of the windings of motor 122 and interface 126.

[0025] In an embodiment according to the present application, the power consuming device 1 can include a pre-charge circuit 114 coupled between the battery 111 and the power converter 113, the pre-charge circuit 114 including a switch K113 coupled in series between the positive terminal of the battery 111 and the positive terminal of a capacitor C11 coupled in parallel with the input of the power converter 113, a switch K115 coupled in series between the negative terminal of the battery 111 and the negative terminal of the capacitor C11, and a switch K114 coupled in parallel across K115 after being coupled in series with a resistor. Similarly, the power consuming device 2 can include a pre-charge circuit 124 coupled between the battery 121 and the power converter 123, the pre-charge circuit 124 including a switch K123 coupled in series between the positive terminal of the battery 121 and the positive terminal of a capacitor C12 coupled in parallel with the input of the power converter 123, a switch K125 coupled in series between the negative terminal of the battery 121 and the negative terminal of the capacitor C12, and a switch K124 coupled in parallel across K125 after being coupled in series with a resistor. It should be understood that, in an embodiment according to the present application, referring to Figure 2 , alternatively, K113 can be coupled in series between the negative terminal of the battery 111 and the negative terminal of the capacitor C11, K115 can be coupled in series between the positive terminal of the battery 111 and the positive terminal of the capacitor C11, and K123 can be coupled in series between the negative terminal of the battery 121 and the negative terminal of the capacitor C12, K125 can be coupled in series between the positive terminal of the battery 121 and the positive terminal of the capacitor C12.

[0026] Figure 2 is a structural schematic diagram of a system 200 for battery heating according to an embodiment of the present application. The system 200 is suitable for the case of battery heating between two power consuming devices through a charging post. Figure 2 The components in the structure of Figure 1 are not described in detail here.

[0027] As shown in Figure 2 , the system 200 can include a control module 220 arranged at the charging post, the control module 220 coupled to the control systems of the power consuming device 1 and the power consuming device 2 for coordinated control of the power converters and other switches in the power consuming device 1 and the power consuming device 2 as well as the charging post.

[0028] Instead of Figure 1As shown in the interface for electrical coupling between electrical devices in the middle, the electrical device 1 can include a charging socket 118 engaged with the charging gun 231 of the charging post, and the electrical device 2 can include a charging socket 128 engaged with the charging gun 232 of the charging post. The system 200 can include a switch K231 coupled in series between the charging guns 231 and 232, specifically, the switch K231 is coupled in series between the positive terminal of the charging gun 231 and the positive terminal of the charging gun 232. In embodiments according to the present application, the system 200 can further include a switch K232 coupled in series between the charging guns 231 and 232, specifically, the switch K232 is coupled in series between the negative terminal of the charging gun 231 and the negative terminal of the charging gun 232.

[0029] In embodiments according to the present application, the system 200 can further include switches K211 and K212 coupled in series between the charging gun 231 of the charging post and the power module 210, where K211 is coupled in series between the positive terminal of the charging gun 231 and one positive terminal of the power module 210, and K212 is coupled in series between the negative terminal of the charging gun 231 and the negative terminal of the power module 210. In embodiments according to the present application, the system 200 can further include switches K221 and K222 coupled in series between the charging gun 232 of the charging post and the power module 210, where K221 is coupled in series between the positive terminal of the charging gun 232 and another positive terminal of the power module 210, and K222 is coupled in series between the negative terminal of the charging gun 232 and another negative terminal of the power module 210. It should be understood that the system 200 can also include one or more of the switches K211, K212, K221, K222 instead of all of them.

[0030] In embodiments according to the present application, the electrical device 1 can further include switches K117 and K118 coupling the battery 111 in parallel to the charging socket 118, where K117 is coupled in series between the positive terminal of the capacitor C1 and the positive terminal of the charging socket 118, and K118 is coupled in series between the negative terminal of the capacitor C1 and the negative terminal of the charging socket 118. Similarly, the electrical device 2 can further include switches K127 and K128 coupling the battery 121 in parallel to the charging socket 128, where K127 is coupled in series between the positive terminal of the capacitor C1 and the positive terminal of the charging socket 118, and K128 is coupled in series between the negative terminal of the capacitor C1 and the negative terminal of the charging socket 118. It should be understood that one or more of the switches K117, K118, K127, K128 can also be included instead of all of them.

[0031] Figure 3 is a flowchart of a method 300 for battery heating according to an embodiment of the present application. The method 300 can be performed at an electrical device (e.g., the electrical device 1 or 2) as shown in the interface for electrical coupling between electrical devices in the middle. Figure 1In the illustrated system 100), the battery heating step can also be performed at the charging station (in the illustrated system 200). Figure 2

[0032] As Figure 3 As illustrated, at step S31, a first interface electrically coupled to a negative terminal of a battery of the first electric device can be joined to a third interface electrically coupled to a negative terminal of a battery of the second electric device; at step S32, a second interface electrically coupled to a neutral point of a motor winding of the first electric device can be joined to a fourth interface electrically coupled to a neutral point of a motor winding of the second electric device; and at step S33, a battery heating step can be performed to heat the batteries of the first and / or second electric devices. It should be understood that steps S31 and S32 can be performed in the order illustrated, can be performed simultaneously, or can be performed in the reverse order of that illustrated.

[0033] In embodiments according to the present application, the battery heating step can include charging the battery of the second electric device with the battery of the first electric device. Specifically, charging the battery of the second electric device with the battery of the first electric device can include closing switches of upper bridge arms of a three-phase power converter of the first electric device and opening switches of lower bridge arms of the three-phase power converter of the first electric device, and opening switches of the upper bridge arms of the three-phase power converter of the second electric device and closing switches of the lower bridge arms of the three-phase power converter of the second electric device, to inductively charge motor windings of the first and second electric devices with discharges of the battery of the first electric device, and closing the switches of the upper bridge arms of the three-phase power converter of the second electric device and opening the switches of the lower bridge arms of the three-phase power converter of the second electric device, to charge the battery of the second electric device after the inductive charging.

[0034] In embodiments according to the present application, the battery heating step can further include charging the battery of the first electric device with the battery of the second electric device. Specifically, charging the battery of the first electric device with the battery of the second electric device can include opening switches of upper bridge arms of a three-phase power converter of the first electric device and closing switches of lower bridge arms of the three-phase power converter of the first electric device, and closing the switches of the upper bridge arms of the three-phase power converter of the second electric device and opening the switches of the lower bridge arms of the three-phase power converter of the second electric device, to inductively charge motor windings of the first and second electric devices with discharges of the battery of the second electric device, and closing the switches of the upper bridge arms of the three-phase power converter of the first electric device and opening the switches of the lower bridge arms of the three-phase power converter of the first electric device, to charge the battery of the first electric device after the inductive charging.

[0035] ​In embodiments according to the present application, a pre-charging step can also be performed by the pre-charging circuit and the control module before the battery heating step is performed.

[0036] In embodiments according to the present application, a parameter of the battery of at least one of the first electrical device and the second electrical device can also be obtained before the battery heating step is performed, and it is determined whether the parameter satisfies a self-heating condition. If yes, the first switch coupled in series between the neutral point of the first electrical device and the first interface and the second switch coupled in series between the neutral point of the second electrical device and the third interface are closed.

[0037] In embodiments according to the present application, a temperature of the battery of at least one of the first electrical device and the second electrical device can also be obtained, and it is determined whether the temperature satisfies a predetermined condition. If no, at least one of the step of charging the battery of the second electrical device by the battery of the first electrical device and the step of charging the battery of the first electrical device by the battery of the second electrical device is repeated until the predetermined condition is satisfied.

[0038] The following describes a method of directly performing battery heating between two electrical devices. Figure 1

[0039] Step 1: The electrical device 1 and the electrical device 2 can be connected to each other through the interfaces 115 and 125, and 116 and 126, and after the connection, the electrical device 1 as the rescue vehicle can obtain the parameters of the battery 121 of the electrical device 2 as the rescued vehicle, such as but not limited to one or more of the battery pack temperature, the state of charge (SOC), the voltage signal, and the like.

[0040] Step 2: The control module 117 can determine whether the self-heating condition is satisfied according to the parameters of the battery 121. As a non-limiting example, the self-heating condition can include whether the battery pack temperature is lower than a predetermined temperature, whether the SOC is higher than a predetermined SOC, whether the voltage amplitude is higher than a predetermined voltage amplitude, and the like. If the self-heating condition is satisfied, the self-heating mode can be started, and the information of the two electrical devices is exchanged. As shown in FIG. 1B, the switches K116 and K126 can be closed under the control of the control module 117. If the self-heating condition is not satisfied, no operation is performed subsequently. In embodiments according to the present application, the same determination can also be performed for the battery 111 of the electrical device 1 as the rescue vehicle, and in the case where the parameters of at least one of the battery 111 and the battery 121 satisfy the self-heating condition, the self-heating mode is started. In this way, it can be ensured that the rescue vehicle has the rescue capability and the rescued vehicle has the necessity of being rescued before the battery heating step is performed. Figure 1

[0041] ​​Step 3: Before the battery heating step, the capacitor C11 connected in parallel to the input of the three-phase power converter 113 can be pre-charged based on the pre-charge circuit 114. For example... Figure 1 As shown, switches K113 and K114 can be closed under the control of control module 117, thereby pre-charging capacitor C11 using battery 111. After pre-charging is complete, switch K115 can be closed, and then switch K114 can be opened. Similarly, in embodiments according to this application, battery 121 can pre-charge capacitor C12 connected in parallel to the input of three-phase power converter 123 using pre-charging circuit 124. Figure 1 As shown, switches K123 and K124 can be closed under the control of control module 117, thereby pre-charging capacitor C12 using battery 121. After pre-charging is complete, switch K125 can be closed, and then switch K124 can be opened. In this way, the DC bus capacitor of the three-phase power converter can be ensured to operate normally, thus facilitating the execution of the battery heating step.

[0042] Step 4: The inductors of motors 112 and 122 can be charged by discharging the battery 111. Specifically, under the control of the control module 117, the switches V11, V12, and V13 of the upper bridge arm of the three-phase power converter 113 can be closed and the switches V14, V15, and V16 of the lower bridge arm of the three-phase power converter 113 can be opened. Additionally, the switches V21, V22, and V23 of the upper bridge arm of the three-phase power converter 123 can be opened and the switches V24, V25, and V26 of the lower bridge arm of the three-phase power converter 123 can be closed, so as to charge the windings of motors 112 and 122 by discharging the battery 111. The current path at this time is: positive terminal of battery 111 → upper bridge arms V11, V12, V13 of three-phase power converter 113 → inductance of winding of motor 112 → inductance of winding of motor 122 → lower bridge arms V24, V25, V26 of three-phase power converter 123 → negative terminal of battery 111.

[0043] In the present application, the closing and opening of the switches V11 to V16 of the three-phase power converter 113 and the switches V21 to V26 of the three-phase power converter 123 can be realized by control signals applied to the control terminals (such as the gates of MOSFETs and IGBTs, etc.) of these switches. In the control of a conventional AC / DC three-phase power converter, there is a phase difference between the control signals of the switches of each phase to ensure the normal operation of the motor coupled thereto. However, in the present application, control without phase difference is performed, and specifically, in the three-phase power converter 113, there is no phase difference between the control signals of the upper arm switches V11, V12, V13 belonging to the three phases, so that the three switches V11, V12, V13 are simultaneously closed or opened, and there is no phase difference between the control signals of the lower arm switches V14, V15, V16 belonging to the three phases, so that the three switches V14, V15, V16 are simultaneously closed or opened. In the three-phase power converter 123, there is no phase difference between the control signals of the upper arm switches V21, V22, V23 belonging to the three phases, so that the three switches V21, V22, V23 are simultaneously closed or opened, and there is no phase difference between the control signals of the lower arm switches V24, V25, V26 belonging to the three phases, so that the three switches V24, V25, V26 are simultaneously closed or opened. Also, square wave control signals can be advantageously taken to obtain as large a heating current effective value as possible.

[0044] Step 5: After the inductance is charged, the battery 121 can be charged. Specifically, the switches V24, V25, V26 of the lower arm of the three-phase power converter 123 can be opened under the control of the control module 117, and then the switches V21, V22, V23 of the upper arm of the three-phase power converter 123 are closed to charge the battery 121 through the inductance of the motors 112 and 122. At this time, the current path is: the positive electrode of the battery 111 → the upper arm V11, V12, V13 of the three-phase power converter 113 → the inductance of the winding of the motor 112 → the inductance of the winding of the motor 122 → the upper arm V21, V22, V23 of the three-phase power converter 123 → the positive electrode of the battery 121 → the negative electrode of the battery 121 → the negative electrode of the battery 111.

[0045] Step 6: Steps 4 and 5 can be repeated under the control of the control module 117, i.e., the battery 121 is charged multiple times by the battery 111 until a predetermined condition is met. As a non-limiting example, the predetermined condition can be a predetermined number of charging times. As a non-limiting example, the predetermined condition can be a threshold temperature of the battery 121. In this case, the control module 117 can obtain the temperature of the battery 121 and determine whether the temperature is higher than the threshold temperature; if not, steps 4 and 5 are executed again to quickly charge the battery 121 by the battery 111. In this way, it can be ensured that the battery is heated to the desired threshold temperature, so that the battery can work normally.

[0046] In this application, as a non-limiting example, the threshold temperature can be a preset lower limit of the temperature at which the battery can work normally, such as 0°C or higher for a lithium-ion battery. As a non-limiting example, the threshold temperature can also be a temperature value set by the user.

[0047] Step 7: After charging the battery 121, the inductance of the windings of the motors 112 and 122 can be charged by discharging the battery 121. Specifically, after completing the fast charging of the battery 121, the switches V11, V12, V13 of the upper bridge arm of the three-phase power converter 113 can be opened and the switches V14, V15, V16 of the lower bridge arm of the three-phase power converter 113 can be closed under the control of the control module 117, and the switches V21, V22, V23 of the upper bridge arm of the three-phase power converter 123 can be closed and the switches V24, V25, V26 of the lower bridge arm of the three-phase power converter 123 can be opened, to inductively charge the windings of the motors 112 and 122 by discharging the battery 121. The current path at this time is: the positive electrode of the battery 121 → the upper bridge arm V21, V22, V23 of the three-phase power converter 123 → the inductance of the windings of the motor 122 → the inductance of the windings of the motor 112 → the lower bridge arm V14, V15, V16 of the three-phase power converter 113 → the negative electrode of the battery 121.

[0048] Step 8: After the inductive charging is completed, the battery 111 can be charged. Specifically, the switches V14, V15, V16 of the lower bridge arm of the three-phase power converter 113 can be opened and then the switches V11, V12, V13 of the upper bridge arm of the three-phase power converter 113 can be closed under the control of the control module 117, to charge the battery 111 by the inductance of the motors 112 and 122. The current path at this time is: the positive electrode of the battery 121 → the upper bridge arm V21, V22, V23 of the three-phase power converter 123 → the inductance of the windings of the motor 122 → the inductance of the windings of the motor 112 → the upper bridge arm V11, V12, V13 of the three-phase power converter 113 → the positive electrode of the battery 111 → the negative electrode of the battery 111 → the negative electrode of the battery 121.

[0049] Step 9: Steps 7 and 8 can be repeated under the control of the control module 117, i.e. discharging the battery 121 by the battery 111 multiple times until a predetermined condition is met. As a non-limiting example, the predetermined condition can be a predetermined number of discharges. As a non-limiting example, the predetermined condition can be a threshold temperature of the battery 121. In this case, the control module 117 can obtain the temperature of the battery 121 and determine whether the temperature is higher than the threshold temperature; if not, steps 7 and 8 are executed again to discharge the battery 121 quickly by the battery 111.

[0050] It should be understood that the battery heating steps can include only steps 4 and 5 of charging the battery 121 by the battery 111, or can further include steps 7 and 8 of charging the battery 111 by the battery 121 (i.e. discharging the battery 121). In the process of charging and discharging the battery, current will flow through the battery and generate a large amount of heat through the Joule heating effect of the internal resistance of the battery. In this application, on the one hand, due to the neutral point leading out of the motor winding inductance and the control of the three-phase power converter without phase difference between the upper bridge arm switch and the lower bridge arm switch of the three-phase, the motor winding inductance is in parallel, so that the equivalent impedance of the motor is relatively reduced, greatly improving the current flowing through the battery; on the other hand, the battery has the characteristic of large internal resistance at low temperature. Therefore, through the battery heating steps, the self-heating of the battery can be quickly performed.

[0051] Step 10: Steps 4, 5, 7 and 8 can be repeated under the control of the control module 117, i.e. charging and discharging the battery 121 by the battery 111 multiple times until a predetermined condition is met. As a non-limiting example, the predetermined condition can be a threshold temperature of the battery 121. In this case, the control module 117 can obtain the temperature of the battery 121 and determine whether the temperature is higher than the threshold temperature; if not, steps 4, 5, 7 and 8 are executed again to charge and discharge the battery 121 quickly by the battery 111.

[0052] Step 11: After the temperature of the battery 121 reaches the threshold temperature, the heating can be stopped. Specifically, after the switches V11 to V16 and V21 to V26 of the three-phase power converters 113, 123 are turned off under the control of the control module 117, the switches K116 and K126 are turned off, and the self-heating process is completed. In this way, after the battery heating steps are completed, the electrical connection related to the neutral point can be disconnected, and the power converter control related to the battery heating can be ended, so that the electrical device can enter the normal working mode.

[0053] It should be understood that the above steps can be optional rather than necessary.

[0054] In addition, although Figure 1 The case of battery self-heating by charging and discharging between a single rescue vehicle power device 1 and a single rescued vehicle power device 2 is shown in the above, but the power device 1 and the power device 2 can include multiple rescued vehicles, that is, multiple power devices 2 can be connected in parallel to the rescue vehicle multiple power devices 1, and multiple power devices 1 can be charged and discharged with multiple power devices 2.

[0055] The following describes the method of battery heating between dual power devices through a charging pile. Figure 2 The method of battery heating between dual power devices through a charging pile is described.

[0056] Step 1: The power device 1 and the power device 2 can be connected to the charging pile by connecting the charging guns 231 and 232 of the charging pile to the charging sockets 118 and 128 of the power device 1 and the power device 2, respectively, so that the control module 210 can obtain one or more of the parameters of at least one of the batteries 111 and 112, such as but not limited to battery pack temperature, SOC, voltage signal, etc.

[0057] Step 2: The control module 210 can determine whether the self-heating condition is met according to the parameters of at least one of the batteries 111 and 112. As a non-limiting example, the self-heating condition can include whether the battery pack temperature is lower than a predetermined temperature, whether the SOC is higher than a predetermined SOC, whether the voltage amplitude is higher than a predetermined voltage amplitude, etc. If the self-heating condition is met, the self-heating mode can be started. As Figure 2 shown, the switches K231 and K232 can be closed under the control of the control module 210 to couple the power device 1 and the power device 2 for self-heating of the battery. If the self-heating condition is not met, it can jump to step 12 for charging.

[0058] Step 3: Before the battery heating step, pre-charging can be performed based on the pre-charging circuit, the specific process of which is described above and will not be described in detail here.

[0059] Step 4: The inductance of the motors 112 and 122 can be charged using the discharge of the battery 111, and the specific process is described above and will not be described in detail here.

[0060] Step 5: After the inductance is charged, the battery 121 can be charged, and the specific process is described above and will not be described in detail here.

[0061] Step 6: Steps 4 and 5 can be repeated under the control of the control module 117, and the specific process is described above and will not be described in detail here.

[0062] Step 7: After charging the battery 121, the inductances of the electric machines 112 and 122 can be charged using the discharge of the battery 121, the details of which are described above and will not be repeated here.

[0063] Step 8: After the inductances are charged, the battery 111 can be charged, the details of which are described above and will not be repeated here.

[0064] Step 9: Steps 7 and 8 can be repeated under the control of the control module 117, the details of which are described above and will not be repeated here.

[0065] Step 10: Steps 4, 5, 7 and 8 can be repeated under the control of the control module 117 until a predetermined condition is met. As a non-limiting example, the predetermined condition can be a threshold temperature of at least one of the batteries 111 and 112. In this case, the control module 117 can obtain the temperature of at least one of the batteries 111 and 112, and determine whether the temperature is higher than the threshold temperature; if not, steps 4, 5, 7 and 8 are executed again to quickly charge and discharge the batteries 111 and 112.

[0066] Step 11: After the temperature of at least one of the batteries 111 and 112 reaches the threshold temperature, heating can be stopped. Specifically, after the control module 117 controls the switches V11 to V16 and V21 to V26 of the three-phase power converters 113 and 123 to be turned off, the switches K116 and K126 are turned off, and the self-heating process is completed. In this way, after the battery heating step is completed, the electrical connection related to the neutral point is disconnected, and the power converter control related to the battery heating is ended, so that the electrical device can enter the normal working mode.

[0067] Step 12: After the self-heating process is completed, the charging mode can be started. As shown in Figure 2 , the switches K117, K118, K211 and K212 can be closed to charge the battery 111 using the power module 210 of the charging pile. At this time, the current path is: the positive terminal of the power module 210 → the positive electrode of the battery 111 → the negative electrode of the battery 111 → the negative terminal of the power module 210. Similarly, the switches K127, K128, K221 and K222 can be closed to charge the battery 121 using the power module 210 of the charging pile. In this way, after the self-heating process is completed, the electrical device can enter the normal working mode of charging using the charging pile.

[0068] Step 13: After the charging process is completed, the standby mode after charging can be entered. As shown in Figure 2As shown, the switches K117, K118, K211, K212 can be opened to end the charging of the battery 111; the switches K127, K128, K221, K222 can be opened to end the charging of the battery 121.

[0069] It should be understood that each of the above steps can be optional rather than necessary.

[0070] In addition, although Figure 2 The system 200 can include more electrical devices together for charging and discharging of the batteries, as shown in the case of a single electrical device 1 and a single electrical device 2 through a charging pile for self-heating of the batteries.

[0071] According to some embodiments of the present application, referring to Figure 1 The present application provides a device for battery heating arranged in an electrical device 1, comprising: an interface 116 electrically coupled to the neutral point of the motor winding of the electrical device 1, the interface 116 being engageable with an interface 126 electrically coupled to the neutral point of the motor winding of an electrical device 2; an interface 115 electrically coupled to the negative electrode of the battery 111 of the electrical device 1, the interface 115 being engageable with an interface 125 electrically coupled to the negative electrode of the battery of the electrical device 2; and a control module 117 coupled to the control systems of the electrical device 1 and the electrical device 2 to coordinate the control of the electrical device 1 and the electrical device 2, and configured to perform a battery heating step. The battery heating step can include a step of charging the battery 112 with the battery 111 and a step of charging the battery 111 with the battery 112. The device can further include a switch K116, and the control module 117 determines whether a self-heating condition is met before performing the battery heating step, and closes the switch K116 if the self-heating condition is met. The device can further include a pre-charging circuit 114, and the control module 117 performs a capacitive pre-charging with the pre-charging circuit 114 before performing the battery heating step.

[0072] According to some embodiments of the present application, referring to Figure 2The application provides a device for battery heating arranged in a charging pile, comprising: switches K231 and K232 coupled in series between charging guns 231 and 232 of the charging pile, wherein the charging gun 231 can be engaged with a charging socket 118 of an electric device 1, the charging socket 118 is electrically coupled to a neutral point of a motor winding of the electric device 1, the charging gun 232 can be engaged with a charging socket 128 of an electric device 2, the charging socket 128 is electrically coupled to a neutral point of a motor winding of the electric device 2; and a control module 220 coupled to control systems of the electric device 1 and the electric device 2 to coordinate control of the electric device 1, the electric device 2 and the charging pile, and configured to perform a battery heating step. The battery heating step can include a step of charging a battery 112 of the electric device 2 by a battery 111 of the electric device 1 and a step of charging the battery 111 by the battery 112. The electric device 1 can further include a switch K116, the electric device 2 can further include a switch K126, and the control module 220 judges whether a self-heating condition is met before performing the battery heating step, and closes the switches K116 and K126 if the self-heating condition is met. The electric device 1 can further include a pre-charging circuit 114, the electric device 2 can further include a pre-charging circuit 124, and the control module 220 performs a capacitor pre-charging by the pre-charging circuits 114 and 124 before performing the battery heating step. The device can further include switches K211, K212, K221 and K222, and the control module 220 judges whether battery temperatures of the electric device 1 and the electric device 2 meet a predetermined condition, such as opening the switches of a three-phase power converter and opening the switches K116 and K126 if the predetermined condition is met, and closing the switches K211, K212, K221 and K222 to charge the electric device 1 and the electric device 2 by a charging pile power module 210 of the charging pile through the charging pile. The electric device 1 can further include switches K117 and K118, the electric device 2 can further include switches K127 and K128, and the control module 220 opens the switches K117, K118, K127 and K128 in the case that the battery temperatures do not meet the self-heating condition, and closes the switches K117, K118, K127 and K128 in the case that the electric device 1 and the electric device 2 are charged by the charging pile.

[0073] According to some embodiments of the application, referring to Figure 3The application provides a method for battery heating performed at a power consuming device or a charging pile, comprising: connecting an interface electrically coupled to a negative electrode of a battery of a power consuming device 1 to a third interface electrically coupled to a negative electrode of a battery of a power consuming device 2; connecting a second interface electrically coupled to a neutral point of a three-phase motor winding of the power consuming device 1 to a fourth interface electrically coupled to a neutral point of a three-phase motor winding of the power consuming device 2; and performing a battery heating step to charge the battery of the power consuming device 2 with the battery of the power consuming device 1 and charge the battery of the power consuming device 1 with the battery of the power consuming device 2. The method further comprises performing a capacitor pre-charge before performing the battery heating step; determining whether the battery temperature of the power consuming device 1 and the power consuming device 2 meets a predetermined condition; and determining whether the parameters of the power consuming device 1 and the power consuming device 2 meet a self-heating condition.

[0074] It should be understood that, Figure 1 In the above embodiment, the power consuming device 1 is a rescue vehicle and the power consuming device 2 is a rescued vehicle, but the application is not limited thereto, but can be applied to the case where the power consuming device 1 is a rescued vehicle and the power consuming device 2 is a rescue vehicle, and the case where the power consuming device 1 and the power consuming device 2 are both normal vehicles, etc.

[0075] It should be understood that, Figure 1 In the above embodiment, the motor and the three-phase power converter are used, but the application is not limited thereto, but can be applied to other multi-phase motors and corresponding power converters, such as a six-phase motor and a corresponding power converter, a nine-phase motor and a corresponding power converter, etc.

[0076] In the application, the connection between the power consuming devices is achieved through the coupling of the neutral points of the multi-phase synthesis of the motors, so that the current of each phase inductance is reduced by the parallel shunt of the multi-phase motor winding inductance, and the total current flowing through the battery can be increased on the basis of the relatively limited motor per-phase inductance and the current range of the power converter switch, the Joule heat power is increased, and fast heating is achieved; the switch of the power converter can be controlled by a square wave signal without phase difference between the three phases, compared with the conventional scheme of taking a high-frequency triangular wave or a pulse width modulation (PWM) wave as a control signal, the control method is simple, and the effective value of the heating current is greatly improved. Therefore, the technical scheme of the application effectively improves the heating efficiency without replacing the switching device with a switching device having larger current-carrying capacity, and can quickly solve the battery heating problem at low temperature. Moreover, the device and method according to the application do not cause adverse effects on the motor, and reduce the noise and vibration of the motor. In addition, the device and method according to the application do not need to make a lot of modifications to the existing device, but only need to add some switches to easily achieve on the architecture of the existing power consuming device and charging pile.

[0077] Although the present application has been described with reference to preferred embodiments, various modifications can be made to the application without departing from the scope of the application. In particular, the technical features mentioned in the various embodiments can be combined in any way, provided that there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An apparatus for battery heating, the apparatus being arranged at a first electric consumer and comprising: a first interface electrically coupled to a neutral point of a motor winding of the first electric consumer; a second interface electrically coupled to a negative pole of a battery of the first electric consumer; and a control module coupled to control systems of the first electric consumer and a second electric consumer to coordinate control of the first electric consumer and the second electric consumer; wherein: the first interface is configured to engage with a third interface electrically coupled to a neutral point of a motor winding of the second electric consumer; the second interface is configured to engage with a fourth interface electrically coupled to a negative pole of a battery of the second electric consumer; and the control module is configured to perform a battery heating step. the battery heating step comprises charging a battery of the second electric consumer with a battery of the first electric consumer.

2. The apparatus of claim 1, wherein, charging a battery of the second electric consumer with a battery of the first electric consumer comprises:

3. The apparatus of claim 2, wherein, closing switches of upper bridge arms of three-phase power converters of the first electric consumer and opening switches of lower bridge arms of the three-phase power converters of the first electric consumer, and opening switches of the upper bridge arms of the three-phase power converters of the second electric consumer and closing switches of the lower bridge arms of the three-phase power converters of the second electric consumer to inductively charge motor windings of the first electric consumer and the second electric consumer with discharges of the battery of the first electric consumer, and closing switches of the lower bridge arms of the three-phase power converters of the second electric consumer and opening switches of the upper bridge arms of the three-phase power converters of the second electric consumer to charge the battery of the second electric consumer after the inductive charging. the battery heating step further comprises charging a battery of the first electric consumer with a battery of the second electric consumer.

4. The apparatus of claim 2, wherein, charging a battery of the first electric consumer with a battery of the second electric consumer comprises:

5. The apparatus of claim 4, wherein, opening switches of upper bridge arms of three-phase power converters of the first electric consumer and closing switches of lower bridge arms of the three-phase power converters of the first electric consumer, and closing switches of the upper bridge arms of the three-phase power converters of the second electric consumer and opening switches of the lower bridge arms of the three-phase power converters of the second electric consumer to inductively charge motor windings of the first electric consumer and the second electric consumer with discharges of the battery of the second electric consumer, and closing switches of the lower bridge arms of the three-phase power converters of the first electric consumer and opening switches of the upper bridge arms of the three-phase power converters of the first electric consumer to charge the battery of the first electric consumer after the inductive charging. the control module is further configured to, before performing the battery heating step:

6. The apparatus of claim 4, further comprising a first switch coupled in series between a neutral of the first power using device and the first interface, wherein, obtain a parameter of a battery of at least one of the first electric consumer and the second electric consumer, determine whether the parameter satisfies a self-heating condition, if the self-heating condition is satisfied, close the first switch and a second switch coupled in series between the neutral point of the second electric consumer and the third interface. ​ 7. The apparatus of claim 6, wherein, The first and second electrical devices further comprise a pre-charge circuit comprising a third switch coupled in series between one of the positive and negative terminals of the battery and one end of a capacitor coupled in parallel with the input of the three-phase power converter, a fourth switch coupled in series between the other of the positive and negative terminals of the battery and the other end of the capacitor, and a fifth switch coupled in parallel across the fourth switch after being coupled in series with a resistor; and The control module is further configured to perform a pre-charge step before performing the battery heating step, the pre-charge step comprising: closing the third and fifth switches for capacitor pre-charge, and after completing capacitor pre-charge, closing the fourth switch and then opening the fifth switch.

8. The apparatus of claim 6, wherein, The control module is further configured to: obtain a temperature of the battery of at least one of the first and second electrical devices, determine whether the temperature satisfies a predetermined condition, if the predetermined condition is not satisfied, repeating at least one of the steps of charging the battery of the second electrical device with the battery of the first electrical device and charging the battery of the first electrical device with the battery of the second electrical device until the predetermined condition is satisfied.

9. The apparatus of claim 8, wherein, The control module is further configured to, after the predetermined condition is satisfied, open all switches of the three-phase power converters of the first and second electrical devices and then open the first and second switches.

10. The apparatus of claim 6, wherein, The parameters include at least one of a temperature, a state of charge, a voltage of the battery.

11. The apparatus of claim 1, wherein, The first and second electrical devices are each one or more electric vehicles.

12. The apparatus of claim 6, wherein, The self-heating condition includes one or more of: the battery pack temperature is below a predetermined temperature, the SOC is above a predetermined SOC, the voltage amplitude is above a predetermined voltage amplitude.

13. An apparatus for battery heating, the apparatus being arranged at a charging station and comprising: a first switch coupled in series between a first charging gun and a second charging gun of the charging station, wherein the first charging gun is configured to be engageable with a first charging receptacle of a first electrical device, the first charging receptacle being electrically coupled to a neutral point of a motor winding of the first electrical device, and the second charging gun is configured to be engageable with a second charging receptacle of a second electrical device, the second charging receptacle being electrically coupled to a neutral point of a motor winding of the second electrical device; and a control module coupled to control systems of the first and second electrical devices to coordinate control of the first and second electrical devices and the charging station; wherein: the first switch is configured to be closed to electrically couple the neutral point of the motor winding of the first electrical device to the neutral point of the motor winding of the second electrical device; and the control module is configured to perform a battery heating step.

14. The apparatus of claim 13, wherein, The battery heating step comprises charging a battery of the second electrical device with a battery of the first electrical device.

15. The apparatus of claim 14, wherein, Charging the battery of the second electrical device with the battery of the first electrical device includes: closing the switches of the upper bridge arms of the three-phase power converters of the first electrical device and opening the switches of the lower bridge arms of the three-phase power converters of the first electrical device, and opening the switches of the upper bridge arms of the three-phase power converters of the second electrical device and closing the switches of the lower bridge arms of the three-phase power converters of the second electrical device to inductively charge the motor windings of the first electrical device and the second electrical device with discharges of the batteries of the first electrical device and the second electrical device, and closing the switches of the upper bridge arms of the three-phase power converters of the second electrical device and opening the switches of the lower bridge arms of the three-phase power converters of the second electrical device to charge the battery of the second electrical device after inductive charging.

16. The apparatus of claim 14, wherein, The battery heating step further includes charging the battery of the first electrical device with the battery of the second electrical device.

17. The apparatus of claim 16, wherein, Charging the battery of the first electrical device with the battery of the second electrical device includes: opening the switches of the upper bridge arms of the three-phase power converters of the first electrical device and closing the switches of the lower bridge arms of the three-phase power converters of the first electrical device, and closing the switches of the upper bridge arms of the three-phase power converters of the second electrical device and opening the switches of the lower bridge arms of the three-phase power converters of the second electrical device to inductively charge the motor windings of the first electrical device and the second electrical device with discharges of the batteries of the second electrical device, and closing the switches of the upper bridge arms of the three-phase power converters of the first electrical device and opening the switches of the lower bridge arms of the three-phase power converters of the first electrical device to charge the battery of the first electrical device after inductive charging.

18. The apparatus of claim 16, wherein, The first electrical device further includes a second switch coupled in series between a neutral point of the first electrical device and the first charging socket, and the second electrical device further includes a third switch coupled in series between a neutral point of the second electrical device and the second charging socket, wherein the control module is further configured to, before performing the battery heating step: obtaining a parameter of the battery of at least one of the first electrical device and the second electrical device, determining whether the parameter satisfies a self-heating condition, if the self-heating condition is satisfied, closing the second switch and the third switch.

19. The apparatus of claim 18, wherein, The first electrical device and the second electrical device further include a pre-charge circuit including a fourth switch coupled in series between one of a positive electrode and a negative electrode of the battery and one end of a capacitor coupled in parallel to an input of the three-phase power converter, a fifth switch coupled in series between the other of the positive electrode and the negative electrode of the battery and the other end of the capacitor, and a sixth switch coupled in parallel to both ends of the fifth switch after being coupled in series with a resistor; and the control module is further configured to, before performing the battery heating step, perform a pre-charge step including: closing the fourth switch and the sixth switch to perform capacitor pre-charging, and After the capacitor is pre-charged, the fifth switch is closed and the sixth switch is opened.

20. The apparatus of claim 18, wherein, The control module is further configured to: obtain a temperature of a battery of at least one of the first and second electrical devices, determine whether the temperature satisfies a predetermined condition, if the predetermined condition is not satisfied, repeat at least one of the steps of charging the battery of the second electrical device with the battery of the first electrical device and charging the battery of the first electrical device with the battery of the second electrical device until the predetermined condition is satisfied.

21. The apparatus of claim 20, wherein, The charging station further comprises a seventh switch coupled in series between the first charging gun and the power module of the charging station and an eighth switch coupled in series between the second charging gun and the power module of the charging station; and The control module is further configured to: if the predetermined condition is satisfied, open all switches of three-phase power converters of the first and second electrical devices, then open the second and third switches, and close at least one of the seventh and eighth switches to charge at least one of the first and second electrical devices.

22. The apparatus of claim 21, wherein, The parameters include at least one of a temperature, a state of charge, and a voltage of the battery.

23. The apparatus of claim 14 or 16, further comprising a ninth switch coupled in series between the first charging gun and the second charging gun of the charging station to electrically couple a negative terminal of the battery of the first electrically powered apparatus to a negative terminal of the battery of the second electrically powered apparatus, wherein, The first charging gun is further configured to engage with the first charging receptacle to electrically couple to a negative terminal of the battery of the first electrical device, and the second charging gun is further configured to engage with the second charging receptacle to electrically couple to a negative terminal of the battery of the second electrical device; and The control module is further configured to close the ninth switch when the first switch is closed and open the ninth switch when the first switch is opened. The first electrical device further comprises a tenth switch to couple the battery of the first electrical device in parallel to the first charging receptacle, and the second electrical device further comprises an eleventh switch to couple a positive terminal of the battery of the second electrical device in parallel to the second charging receptacle; and 24. The apparatus of claim 21, wherein, The control module is further configured to: if the self-heating condition is satisfied, open the tenth and eleventh switches, and close corresponding ones of the tenth and eleventh switches when charging at least one of the first and second electrical devices with the charging station. The first and second electrical devices are each one or more electric vehicles.

25. The apparatus of claim 13, wherein, The self-heating condition includes one or more of:

26. The apparatus of claim 18, wherein, a battery pack temperature is below a predetermined temperature, an SOC is above a predetermined SOC, a voltage amplitude is above a predetermined voltage amplitude.

27. A method for battery heating, the method being performed at an electrical device or a charging station, and comprising: engaging a first interface electrically coupled to a negative terminal of a battery of a first electrical device to a third interface electrically coupled to a negative terminal of a battery of a second electrical device; engaging a second interface electrically coupled to a neutral point of a motor winding of the first electrical device to a fourth interface electrically coupled to a neutral point of a motor winding of the second electrical device; and performing a battery heating step. ​ ​ 28. The method of claim 27, wherein, The battery heating step includes charging the battery of the second electrical device with the battery of the first electrical device.

29. The method of claim 28, wherein charging the battery of the second electrical device with the battery of the first electrical device includes: closing the switches of the upper bridge legs of the three-phase power converters of the first electrical device and opening the switches of the lower bridge legs of the three-phase power converters of the first electrical device, and opening the switches of the upper bridge legs of the three-phase power converters of the second electrical device and closing the switches of the lower bridge legs of the three-phase power converters of the second electrical device to inductively charge the motor windings of the first and second electrical devices with discharges of the battery of the first electrical device, and closing the switches of the upper bridge legs of the three-phase power converters of the second electrical device and opening the switches of the lower bridge legs of the three-phase power converters of the second electrical device to charge the battery of the second electrical device after inductive charging.

30. The method of claim 28, wherein, The battery heating step further includes charging the battery of the first electrical device with the battery of the second electrical device.

31. The method of claim 30, wherein, Charging the battery of the first electrical device with the battery of the second electrical device includes: opening the switches of the upper bridge legs of the three-phase power converters of the first electrical device and closing the switches of the lower bridge legs of the three-phase power converters of the first electrical device, and closing the switches of the upper bridge legs of the three-phase power converters of the second electrical device and opening the switches of the lower bridge legs of the three-phase power converters of the second electrical device to inductively charge the motor windings of the first and second electrical devices with discharges of the battery of the second electrical device, and closing the switches of the upper bridge legs of the three-phase power converters of the first electrical device and opening the switches of the lower bridge legs of the three-phase power converters of the first electrical device to charge the battery of the first electrical device after inductive charging.

32. The method of claim 28, further comprising, prior to performing the battery heating step: obtaining a parameter of the battery of at least one of the first electrical device and the second electrical device, determining whether the parameter satisfies a self-heating condition, if the self-heating condition is satisfied, closing a first switch coupled in series between a neutral point of the first electrical device and the first interface and a second switch coupled in series between a neutral point of the second electrical device and the third interface.

33. The method of claim 32, wherein, The first and second electrical devices further include a pre-charge circuit including a third switch coupled in series between one of a positive terminal and a negative terminal of a battery and one end of a capacitor coupled in parallel to an input of a three-phase power converter, a fourth switch coupled in series between the other of the positive terminal and the negative terminal of the battery and another end of the capacitor, and a fifth switch coupled in parallel to the fourth switch after being coupled in series with a resistor; and The method further includes, prior to performing the battery heating step, performing a pre-charge step including: closing the third switch and the fifth switch to perform capacitor pre-charge; and and After the capacitor pre-charge is completed, the fourth switch is closed and then the fifth switch is opened.

34. The method of claim 32, further comprising: obtaining a temperature of a battery of at least one of the first and second electrical devices, determining whether the temperature satisfies a predetermined condition, if the predetermined condition is not satisfied, repeating at least one of the step of charging the battery of the second electrical device with the battery of the first electrical device and the step of charging the battery of the first electrical device with the battery of the second electrical device until the predetermined condition is satisfied.

35. The method of claim 34, further comprising: After the predetermined condition is satisfied, all switches of three-phase power converters of the first and second electrical devices are opened and then the first and second switches are opened.

36. The method of claim 35, wherein, In case the method is performed at a charging column, the charging column comprises a sixth switch coupled in series between a first charging gun engageable with the first and second interfaces and a power module of the charging column and a seventh switch coupled in series between a second charging gun engageable with the third and fourth interfaces and the power module of the charging column, and: the method further comprises: in case the self-heating condition is satisfied, opening the sixth and seventh switches, and closing at least one of the sixth and seventh switches to charge at least one of the first and second electrical devices with the charging column.

37. The method of claim 32, wherein, The parameters include at least one of a temperature, a state of charge, a voltage of the battery.

38. The method of claim 32, wherein, In case the method is performed at a charging column, the first electrical device further comprises an eighth switch electrically coupling two poles of the battery of the first electrical device to the first and second interfaces, respectively, and the second electrical device further comprises a ninth switch electrically coupling two poles of the battery of the second electrical device to the third and fourth interfaces, respectively; and the method further comprises: in case the self-heating condition is satisfied, opening the eighth and ninth switches, and in case at least one of the first and second electrical devices is charged with the charging column, closing corresponding ones of the eighth and ninth switches.

39. The method of claim 27, wherein, The first and second electrical devices are each one or more vehicles.

40. The method of claim 32, wherein, The self-heating condition comprises one or more of: a battery pack temperature is lower than a predetermined temperature, a SOC is higher than a predetermined SOC, a voltage amplitude is higher than a predetermined voltage amplitude.

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