Power battery heating circuit, system, control method and electrical equipment

Abstract

The embodiment of the present application provides a power battery heating circuit, system, control method and electrical equipment, the power battery heating circuit comprising: a power supply module, comprising at least one battery pack; an inverter module, connected to the power supply module, comprising an M-phase bridge arm circuit, and the bridge arm circuit is connected in parallel with the battery pack, where M is an even multiple of three; a drive module, comprising a motor having M windings, the M windings being connected one-to-one with the M-phase bridge arms of the bridge arm circuit; a control module, connected to the bridge arm circuit, controlling the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit, and the lower bridge arms of the same phase arms in the remaining bridge arms to be turned on, so that the power supply module, the inverter module and the drive module form an alternating charging circuit and a discharging circuit. The present application can achieve rapid heating of the battery of the power supply module on the basis of the existing multi-phase motor.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a power battery heating circuit, system, control method and electrical equipment. 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 will be subject to certain restrictions. Specifically, the discharge capacity of the power battery will seriously decline in low-temperature environments, and the battery cannot be charged in low-temperature environments. In particular, six-phase motors (or motors with more phases) require more power from the power battery. When the charging and discharging capacity of the power battery is limited, the experience of the six-phase motor vehicle will also be worse. Therefore, in order to be able to use the power battery normally, it is necessary to heat the power battery in a low-temperature environment. Summary of the Invention

[0004] The embodiments of the present application provide a power battery heating circuit, system, control method and electrical equipment, which can achieve rapid heating of the battery of the power supply module based on the existing multi-phase motor.

[0005] In the first aspect, the present application provides a power battery heating circuit, comprising: a power supply module, comprising at least one battery pack; an inverter module, connected to the power supply module, comprising an M-phase bridge arm circuit, and the bridge arm circuit is connected in parallel with the battery pack, M being an even multiple of three; a drive module, comprising a motor having M windings, and the M windings are respectively connected one-to-one with the M-phase bridge arms of the bridge arm circuit; a control module, connected to the bridge arm circuit, for controlling the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit, and the lower bridge arms of the same phase arms in the remaining bridge arms to be turned on, so that the power supply module, the inverter module and the drive module form an alternating charging circuit and a discharging circuit.

[0006] In the technical solution of the embodiment of the present application, by setting a control module connected to the inverter module, the power supply module, the inverter module and the drive module can form a charging circuit or a discharging circuit by controlling the conduction or closing of each phase bridge arm in the bridge arm circuit. When the charging circuit or the discharge circuit is working, current will flow through the battery pack of the power supply module. The battery pack has a certain internal resistance and can consume part of the current to convert electrical energy into thermal energy, thereby generating heat to heat the battery pack of the power supply module. In order to effectively heat the battery pack, especially the battery pack of the six-phase motor drive system, this embodiment uses the control module to control the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit and the lower bridge arms of the same phase arms in the remaining bridge arms to be turned on, so that the power supply module, the inverter module and the drive module form an alternating charging circuit and a discharging circuit to charge and discharge the battery pack. In this way, a cyclic charging and discharging circuit can be formed, and the battery pack can be continuously heated until the temperature of the battery pack reaches the normal operating temperature, so that the power battery can be used normally in a low temperature environment, avoiding the limitation of the charging and discharging capacity of the power battery, and greatly improving the customer's winter car experience.

[0007] In some embodiments, the motor comprises a six-phase symmetrical motor. Since the currents flowing into or out of the three-phase windings of the six-phase symmetrical motor are always of equal magnitude and their directions are symmetrical, the resultant current is small, thereby forming a small resultant magnetic field, thereby preventing the heating circuit from generating large noise during operation.

[0008] In some embodiments, in the charging circuit or the discharging circuit, the spatial phase difference of the three windings respectively connected to the three-phase upper bridge arm is 120°, and the spatial phase difference of the three windings respectively connected to the three-phase lower bridge arm is 120°. In the charging circuit or the discharging circuit, the spatial phase difference of the three windings respectively connected to the three-phase upper (lower) bridge arm is 120°, and the spatial phase difference of the current flowing into (flowing out of) the three-phase winding is 120°, so that the stator magnetic field composed of the three-phase spatially symmetrical windings is close to zero (about 0 to 0.5T), so that when the power battery heating circuit is used to heat the power battery, the vibration noise generated by the interaction between the stator magnetic field and the rotor magnetic field can be effectively suppressed. At the same time, by controlling the synthetic magnetic field of the current flowing into multiple windings belonging to the same motor to 0 to 0.5T, the motor is prevented from running, and the problem of rotor heating in the motor can also be solved, thereby extending the battery self-heating service life.

[0009] In the second aspect, the present application provides a power battery heating control method, which is applied to the power battery heating circuit described in the first aspect. The method includes: sending an enable signal to control the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit, and the lower bridge arms of the same phase arms in the remaining bridge arms to be turned on, so that the power supply module, inverter module and drive module of the battery heating circuit form an alternating charging circuit and a discharging circuit.

[0010] In the technical solution of the embodiment of the present application, the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit and the lower bridge arms of the same phase arms in the remaining bridge arms are all turned on through the control module, so that the power supply module, the inverter module and the drive module form an alternating charging circuit and a discharging circuit to charge and discharge the battery pack. In this way, a cyclic charging and discharging circuit can be formed, and the battery pack can be continuously heated until the temperature of the battery pack reaches the normal operating temperature, so that the power battery can be used normally in a low temperature environment, avoiding the limitation of the charging and discharging capacity of the power battery, and greatly improving the customer's winter car experience.

[0011] In some embodiments, a heating signal is sent to the inverter module at a preset frequency to control the inverter module to alternately switch between the charging circuit and the discharging circuit. This avoids prolonged battery discharge, which can damage the battery, or prolonged motor operation, which can cause the motor rotor to rotate or the stator to heat up.

[0012] In some embodiments, sending a heating signal to the inverter module at a preset frequency includes: alternately sending a first heating signal and a second heating signal to the inverter module at the preset frequency; the first heating signal turns on the upper bridge arms of at least three phases in the bridge arm circuit, as well as the lower bridge arms of the remaining bridge arms with the same phases, thereby forming a charging circuit for the power supply module, inverter module, and driver module of the battery heating circuit; and the second heating signal turns on the lower bridge arms of the at least three phases, as well as the upper bridge arms of the remaining bridge arms with the same phases, thereby forming a discharging circuit for the power supply module, inverter module, and driver module of the battery heating circuit. This effectively heats the power battery while avoiding energy loss and noise caused by prolonged charging or discharging.

[0013] In some embodiments, the motor of the drive module comprises a six-phase symmetrical motor. The first heating signal turns on the upper arms of three phases in the six-phase bridge circuit and the lower arms of the other three phases, thereby forming a charging circuit for the power supply module, inverter module, and drive module of the battery heating circuit. The second heating signal turns on the lower arms of the three phases in the six-phase bridge circuit and the upper arms of the other three phases, thereby forming a discharging circuit for the power supply module, inverter module, and drive module of the battery heating circuit. In the charging or discharging circuit, the spatial phase difference between the three windings connected to the three upper phases is 120°, and the spatial phase difference between the three windings connected to the three lower phases is 120°. By controlling the resultant magnetic field of the current flowing into multiple windings in the same motor to be between 0 and 0.5 T, the motor is prevented from rotating, thereby resolving the problem of rotor heating in the motor and extending the battery self-heating service life.

[0014] In some embodiments, transmitting a heating signal to the inverter module at a preset frequency includes determining whether the battery pack's state of charge (SOC) is greater than or equal to a preset threshold; if so, transmitting a heating signal to the inverter module at the preset frequency. When the power battery's SOC is greater than the preset threshold, the current flowing through the circuit can be modulated into an alternating current (AC), which is used to generate heat through the power battery's internal resistance, thereby heating the power battery and improving heating efficiency. When the battery SOC is less than or equal to the preset threshold, i.e., when the battery charge is low, a DC current is used to generate heat in the windings to heat the power battery, reducing power consumption and increasing the flexibility of the power battery heating system.

[0015] In some embodiments, transmitting a heating signal to the inverter module at a preset frequency includes: obtaining the operating state of the motor; and if the motor is in a non-driving state, transmitting a heating signal to the inverter module at a preset frequency. By determining the operating state of the motor, heating of the power battery can be prevented when the motor is in a driving state, thereby affecting the performance of a power device such as a vehicle.

[0016] In some embodiments, sending a heating signal to the inverter module at a preset frequency includes: receiving a control signal from a vehicle controller; and if the control signal indicates that the power battery is to be heated, sending a heating signal to the inverter module at a preset frequency. By receiving the control signal from the vehicle controller, a heating mode can be quickly entered to promptly heat the power battery.

[0017] In some embodiments, sending a heating signal to the inverter module at a preset frequency includes: receiving request data from a battery management system; if the request data indicates that the power battery meets heating conditions, sending a heating signal to the inverter module at a preset frequency. By receiving the heating request from the BMS, the control module can promptly control the power battery heating system to heat the power battery, thereby avoiding affecting the use of power devices such as the vehicle.

[0018] In some embodiments, the method further includes: determining whether the temperature of the battery pack meets a stop heating condition; the stop heating condition includes the battery pack reaching a preset temperature or the temperature rise of the power battery being abnormal; if so, sending a stop heating signal to the inverter module, the stop heating signal causing the inverter module to disconnect the charging circuit or the discharging circuit. By setting a stop heating signal, heating can be stopped in a timely manner after the battery pack temperature rises abnormally or reaches the normal operating temperature, thereby avoiding wasting resources and facilitating timely use by users.

[0019] In a third aspect, the present application provides a power battery heating system, which includes a heating controller and a power battery heating circuit as described in any one of the first aspects; the heating controller is used to send instructions to the power battery heating circuit to control the power battery heating circuit to form an alternating charging circuit and a discharging circuit.

[0020] In a fourth aspect, the present application provides an electrical device comprising the power battery heating system as described in the third aspect.

[0021] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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.

[0023] Figure 1 This is a schematic block diagram of a power battery heating circuit provided in one embodiment of the present application;

[0024] Figure 2 This is a circuit diagram (discharge circuit) of a power battery heating circuit provided in one embodiment of the present application;

[0025] Figure 3 This is a circuit diagram of a power battery heating circuit (charging circuit) provided in one embodiment of the present application;

[0026] Figure 4 This is a flow chart of a control method for a power battery heating scenario provided by an embodiment of the present application;

[0027] Figure 5 This is a schematic block diagram of a heating controller provided in one embodiment of the present application. DETAILED DESCRIPTION

[0028] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0030] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0031] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0033] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0034] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0035] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0036] 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.

[0037] The present application notes that due to the electrochemical characteristics of power batteries, the charge and discharge capabilities of power batteries are greatly limited in low-temperature environments, seriously affecting the customer's winter vehicle experience. In particular, six-phase motors (or motors with more phases) require more power from power batteries. When the charge and discharge capabilities of power batteries are limited, the experience of six-phase motor vehicles will also be worse. Therefore, in order to be able to use the power battery normally, it is necessary to heat the power battery in low-temperature environments.

[0038] In order to improve the charge and discharge capabilities of power batteries in low-temperature environments, this application has found that in order to avoid unnecessary costs when heating the power battery, the motor circuit can be used to heat the power battery. Specifically, the motor generates heat during operation, and the heat generated by the motor windings can be absorbed by the vehicle cooling system, and the absorbed heat is then transferred to the power battery to heat the power battery. However, when the battery is heated through the motor circuit, the cooling system itself will consume part of the heat, which greatly reduces the heating capacity of the power battery. And as a battery-powered drive system, when the charge and discharge capacity of the power battery is greatly limited, its power supply capacity to the motor will also decrease, the heat generated by the motor windings will also decrease significantly, and the heating effect on the power battery will also be greatly weakened, making it impossible to effectively heat the power battery.

[0039] Based on the above considerations, in order to solve the problem that the charging and discharging capabilities of power batteries are greatly limited in low temperature environments, which seriously affects the customer's winter car-using experience, this application has designed a power battery heating circuit after in-depth research. By setting a control module and setting the control module to be connected to the bridge arm circuit of the inverter module, the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit and the lower bridge arms of the same phase arms in the remaining bridge arms can be controlled to be turned on, so that the power supply module, the inverter module and the drive module form an alternating charging circuit and a discharging circuit.

[0040] By applying such a power battery heating circuit, a control module connected to the inverter module is set up, and the conduction or closing of each phase bridge arm in the bridge arm circuit can be controlled to form a charging circuit or a discharging circuit among the power supply module, the inverter module and the drive module. When the charging circuit or the discharging circuit is working, current will flow through the battery pack of the power supply module. The battery pack has a certain internal resistance and can consume part of the current, converting electrical energy into thermal energy, thereby generating heat to heat the battery pack of the power supply module.

[0041] In order to effectively heat the battery pack, especially the battery pack of the six-phase motor drive system, this embodiment uses the control module to control the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit and the lower bridge arms of the same phase arms in the remaining bridge arms to be turned on, so that the power supply module, the inverter module and the drive module form an alternating charging circuit and a discharging circuit to charge and discharge the battery pack. In this way, a cyclic charging and discharging circuit can be formed, and the battery pack can be continuously heated until the temperature of the battery pack reaches the normal operating temperature, so that the power battery can be used normally in a low temperature environment, avoiding the limitation of the charging and discharging capacity of the power battery, and greatly improving the customer's winter car experience.

[0042] The power battery in the embodiment of the present application may be, but is not limited to, 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., and is not limited here. In terms of scale, the battery in the embodiment of the present application may be a single cell, or a battery module or a battery pack, and is not limited here. In terms of application scenarios, the battery may be, but is not limited to, used in power devices such as automobiles and ships. For example, it can be used in a power car to power the motor of the power car and serve as a power source for the electric car. The battery can also power other electrical devices in the electric car, such as the air conditioner in the car, the car player, etc.

[0043] For the convenience of description, the following embodiments are described by taking an electrical device in an embodiment of the present application as a new energy vehicle (power vehicle) as an example.

[0044] The drive system is a core component of new energy vehicles, and its driving characteristics determine the vehicle's primary performance indicators. The motor drive system of a new energy vehicle primarily consists of an electric motor (i.e., motor), a motor controller, various detection sensors, and a power supply module. The motor is a rotating electromagnetic machine that operates on the principle of electromagnetic induction, converting electrical energy into mechanical energy. During operation, it draws electrical power from the power supply module and outputs mechanical power to the mechanical system.

[0045] In order to ensure that the power battery can be used normally in a low-temperature environment, the battery pack of the power supply module can be heated by the power battery heating circuit provided in the embodiment of the present application.

[0046] According to some embodiments of the present application, referring to Figure 1 , and please refer to Figure 2 and Figure 3 , Figure 1 This is a modular schematic diagram of a power battery heating circuit provided in some embodiments of the present application. Figure 2 A schematic diagram of a structure of a power battery heating circuit forming a discharge circuit according to some embodiments of the present application. Figure 3A schematic diagram of a power battery heating circuit forming a charging circuit for some embodiments of the present application. The present application provides a power battery heating circuit, which includes a power supply module 210, an inverter module 220, a drive module 230, and a control module 240. The power supply module 210 includes at least one battery pack. The inverter module 220 is connected to the power supply module 210 and includes an M-phase bridge arm circuit, and the bridge arm circuit is connected in parallel with the battery pack, where M is an even multiple of three. The drive module 230 includes a motor with M windings, and the M windings are respectively connected one-to-one with the M-phase bridge arms of the bridge arm circuit. The control module 240 is connected to the bridge arm circuit to control the upper bridge arms of at least three phases in the bridge arm circuit and the lower bridge arms of the same phases in the remaining bridge arms to be turned on, so that the power supply module 210, the inverter module 220, and the drive module 230 form an alternating charging circuit and a discharging circuit to charge and discharge the battery pack.

[0047] The power supply module 210 is implemented using a power battery and includes at least one battery pack. The battery pack can be a collection of multiple battery modules or a battery module including multiple battery cells.

[0048] For the inverter module 220, various types of switches can be used for implementation. For example, the inverter module 220 can be implemented by an inverter in a motor drive system, wherein the inverter can be implemented by a bridge arm circuit of an insulated gate bipolar transistor (IGBT). Specifically, the number of bridge arms of the bridge arm circuit is the same as the number of windings in the drive module 230, which is at least six phases. For example, the drive module 230 includes a six-phase motor, and the bridge arm circuit includes six-phase bridge arms, which may include an A-phase bridge arm, a B-phase bridge arm, a C-phase bridge arm, a D-phase bridge arm, an E-phase bridge arm and an F-phase bridge arm, or may include two U-phase bridge arms, two V-phase bridge arms and two W-phase bridge arms. Wherein, each phase bridge arm has an upper bridge arm and a lower bridge arm, and its upper bridge arm and lower bridge arm are each provided with a switch unit.

[0049] The driving module 230 may specifically include: M-phase windings connected to the bridge arm, wherein the multiple windings are connected in a collinear manner, have a common connection point, and an end of each winding away from the common connection point is respectively connected to the connection point of the upper bridge arm and the lower bridge arm of a phase bridge arm.

[0050] The control module 240 sends a heating signal (i.e., an enabling signal) to the inverter module 220. The heating signal controls the switch units of the upper and lower bridge arms to control the on and off of the upper and lower bridge arms. The control module 240 can be a vehicle control unit (VCU) and / or a motor control unit (MCU), or a separate controller specifically configured to control the aforementioned bridge arm circuits to form a charge and discharge loop. This embodiment does not specifically limit this.

[0051] The battery pack, the M-phase bridge arm and the motor are connected in parallel; the upper and lower bridge arm connection points of the M-phase bridge arm are respectively connected one-to-one with the M-phase winding of the M-phase motor; the control module 240 controls the upper and lower bridge arms of the bridge arm circuit to be turned on or off to alternately switch the charging circuit and the discharging circuit, so that current flows inside the power supply module 210, thereby generating heat to heat the power supply module 210.

[0052] Specifically, the motor may be a six-phase symmetrical motor. Since the spatial phase difference of the M windings of the symmetrical motor may be a ratio of 360° to M, the spatial phase difference of the six windings of the six-phase symmetrical motor is 60°.

[0053] The magnetomotive force of a unidirectional winding is a pulsating magnetomotive force with a step-like distribution in space, alternating over time according to the changing laws of current. The combined magnetomotive force of the six single-phase windings in a six-phase motor yields the combined magnetic field. The larger the combined magnetic field, the more intense the motor's vibration and the louder the vibration noise.

[0054] A six-phase symmetrical motor is used, and accordingly, the bridge arm circuit of inverter module 220 also includes six phases. When forming a charging or discharging circuit, control module 240 controls the upper arms of any three of the six phases to be conductive, while the lower arms of the remaining three phases are conductive. Current enters three of the six windings and exits the remaining three. For a six-phase symmetrical motor, since the currents flowing into or out of the three-phase windings are always equal in magnitude and their directions are symmetrical, the resulting composite current is small, thereby forming a smaller composite magnetic field, which prevents the heating circuit from generating excessive noise during operation.

[0055] It should be noted that the drive module 230 is not limited to a six-phase motor, but can also be a twelve-phase motor or other motor with more than six phases. Correspondingly, the inverter module 220 can include three-phase bridge arms or six-phase bridge arms. The number of upper bridge arms and lower bridge arms that are turned on at each time is the same.

[0056] Furthermore, when the motor is a six-phase symmetrical motor, in the charging circuit or the discharging circuit, the spatial phase difference of the three windings (which can be called the first winding) respectively connected to the three-phase upper bridge arms that are turned on is 120°, and the spatial phase difference of the three windings (which can be called the second winding) respectively connected to the three lower bridge arms that are turned on is 120°.

[0057] In the charging or discharging circuit, the spatial phase difference between the three windings connected to the conductive three-phase upper (lower) bridge arm is 120°. The spatial phase difference between the currents flowing into (and out of) the three-phase windings is 120°, making the stator magnetic field composed of the three-phase spatially symmetrical windings close to zero (approximately 0 to 0.5T). This effectively suppresses the vibration noise generated by the interaction between the stator magnetic field and the rotor magnetic field when the power battery heating circuit is used to heat the power battery. At the same time, by controlling the synthetic magnetic field of the currents flowing into multiple windings belonging to the same motor to 0 to 0.5T, the motor is prevented from operating, and the problem of rotor heating in the motor is solved, thereby extending the battery self-heating service life.

[0058] The following combination Figure 2 and Figure 3 , describes in detail the circuit diagram of the power battery heating circuit provided in the embodiment of the present application.

[0059] like Figure 2 As shown, the six windings of the six-phase motor can be respectively a first winding and a second winding, wherein the first windings are winding 311, winding 312, and winding 313 in the six-phase motor, and the second windings are winding 314, winding 315, and winding 316 in the six-phase motor. The six-phase bridge arms may include bridge arms 331-336, wherein bridge arms 331, bridge arms 332, and bridge arms 333 are respectively connected to winding 311, winding 312, and winding 313 in the first winding. Bridge arms 334, bridge arms 335, and bridge arms 336 are respectively connected to winding 314, winding 315, and winding 3163 in the second winding.

[0060] Specifically, the connection point between the upper bridge arm 3311 and the lower bridge arm 3312 of the bridge arm 331 is connected to one end of the winding 311, the connection point between the upper bridge arm 3321 and the lower bridge arm 3322 of the bridge arm 332 is connected to one end of the winding 312, the connection point between the upper bridge arm 3331 and the lower bridge arm 3332 of the bridge arm 333 is connected to one end of the winding 313, the connection point between the upper bridge arm 3341 and the lower bridge arm 3342 of the bridge arm 334 is connected to one end of the winding 314, the connection point between the upper bridge arm 3351 and the lower bridge arm 3352 of the bridge arm 335 is connected to one end of the winding 315, and the connection point between the upper bridge arm 3361 and the lower bridge arm 3362 of the bridge arm 336 is connected to one end of the winding 316.

[0061] The power supply module 210, the upper bridge arms 3311-3331, the windings 311-313, the windings 314-316 and the lower bridge arms 3342-3362 together form a discharge circuit. Figure 2 Similarly, the power supply module 210, the lower bridge arms 3312-3332, the windings 311-313, the windings 314-316 and the upper bridge arms 3341-3361 together form a charging circuit, as shown in FIG. Figure 3 Under the control of the control module 240 , the charging circuit and the discharging circuit are periodically and alternately turned on.

[0062] exist Figure 2 and Figure 3 In the illustrated embodiment, by controlling the spatial phase difference between the three windings (311-313) where the current flows in, and the spatial phase difference between the three windings (314-316) where the current flows out, to be 120°, the motor's vibration noise can be effectively suppressed when the six-phase motor's circuit is used to heat the power battery. Furthermore, because the power battery heating system provided in this embodiment of the application does not cause the motor to operate, it can solve the problem of rotor heating in the motor, thereby extending the battery's self-heating service life.

[0063] It should be noted that windings 311 to 313 can be used as input windings, and windings 314 to 316 can be used as output windings. Alternatively, windings 311 to 313 can be used as output windings, and windings 314 to 316 can be used as input windings. As long as the upper bridge arm of the three-phase bridge arm connected to windings 311 to 313 and the lower bridge arm of the three-phase bridge arm connected to windings 314 to 316 keep the switch unit turned on or off at the same time, and the lower bridge arm of the three-phase bridge arm connected to windings 311 to 313 and the upper bridge arm connected to windings 314 to 316 keep the switch unit turned on or off at the same time, the switching unit can be realized. Figure 2 The discharge circuit shown and Figure 3 The charging circuit shown.

[0064] Optionally, Figure 2 and Figure 3 The power battery heating circuit shown also includes a capacitor C connected in parallel with the power supply module 210 , which mainly plays the role of voltage stabilization and noise filtering.

[0065] Based on the same concept as the above-mentioned power battery heating circuit, an embodiment of the present application also provides a power battery heating control method, which can be applied to the above-mentioned power battery heating circuit. The method includes: sending an enable signal to control the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit, and the lower bridge arms of the same phase arms in the remaining bridge arms to be turned on, so that the power supply module 210, the inverter module 220 and the drive module 230 of the battery heating circuit form an alternating charging circuit and a discharging circuit.

[0066] Among them, the enable signal is usually a high-level or low-level digital signal, which is used to control the on and off of the bridge arm switch in the bridge arm circuit. For example, the high-level control bridge arm circuit turns on the upper bridge arm and turns off the lower bridge arm. When a phase bridge arm receives a high-level enable signal sent by the control module 240, the upper bridge arm of the phase bridge arm is turned on and the lower bridge arm is turned off.

[0067] In some embodiments, the control module 240 may send heating signals to different bridge arms in the inverter module 220 at a preset frequency to control the inverter module 220 to alternately switch between the charging circuit and the discharging circuit.

[0068] The preset frequency, i.e., the number of times per unit time that a heating signal is sent to different bridge arms of the inverter module 220, can be used to define the time interval between two heating signal transmissions. In other words, the control module 240 begins timing when sending a heating signal to the inverter module 220, and after a predetermined time interval, sends a heating signal to the inverter module 220 again. Furthermore, two adjacent heating signals are sent to different bridge arms, thereby controlling the inverter module 220 to alternately switch between the charging circuit and the discharging circuit.

[0069] If the time interval is too long, the battery may be discharged for a long time, which will consume the battery and further reduce the battery discharge efficiency. Or it may cause the motor to work for a long time, which may cause the motor rotor to rotate or the stator to heat up. If the time interval is too long, because the current passing through the battery is relatively small, the heat generated in a short time may not be enough to effectively heat the battery pack. Therefore, in this embodiment, the control module 240 is configured to send heating signals to different bridge arms in the inverter module 220 at a preset frequency. The preset frequency can be selected according to actual conditions to avoid the time interval for sending the heating signal being too short or too long.

[0070] Specifically, when the control module 240 sends a heating signal to the inverter module 220 at a preset frequency, it may alternately send a first heating signal and a second heating signal to the inverter module 220 at the preset frequency. The first heating signal turns on the upper bridge arms of at least three phases in the bridge arm circuit, as well as the lower bridge arms of the remaining bridge arms with the same phases, thereby forming a charging circuit among the power supply module 210, the inverter module 220, and the drive module 230 of the battery heating circuit. The second heating signal turns on the lower bridge arms of at least three phases, as well as the upper bridge arms of the remaining bridge arms with the same phases, thereby forming a discharging circuit among the power supply module 210, the inverter module 220, and the drive module 230 of the battery heating circuit.

[0071] Among them, the first heating signal and the second heating signal are similar to the above-mentioned enable signal, and both can be high-level or low-level digital signals, which are used to control the on and off of the bridge arm switch in the bridge arm circuit. For example, the high-level control bridge arm circuit turns on the upper bridge arm and turns off the lower bridge arm. When a phase bridge arm receives a high-level enable signal sent by the control module 240, the upper bridge arm of the phase bridge arm is turned on and the lower bridge arm is turned off.

[0072] The control module 240 sends a first heating signal and a second heating signal to the inverter module 220 at the above-mentioned preset frequency, and respectively controls the corresponding bridge arms in the bridge arm circuit to be turned on and off, so that the power supply module 210, the inverter module 220 and the drive module 230 of the battery heating circuit alternately form a charging circuit and a discharging circuit at the corresponding frequency, which can not only realize the effective heating function of the power battery, but also avoid energy loss and noise caused by long-term charging or discharging.

[0073] When the motor of the drive module is a six-phase symmetrical motor, specifically, the first heating signal turns on the upper bridge arms of three phases in the six-phase bridge arm circuit, as well as the lower bridge arms of the remaining three phases, thereby forming a charging circuit for the power supply module 210, inverter module 220, and drive module 230 of the battery heating circuit. The second heating signal turns on the lower bridge arms of three phases in the six-phase bridge arm circuit, as well as the upper bridge arms of the remaining three phases, thereby forming a discharging circuit for the power supply module 210, inverter module 220, and drive module 230 of the battery heating circuit. In either the charging or discharging circuit, the spatial phase difference between the three windings connected to the three upper bridge arms is 120°, and the spatial phase difference between the three windings connected to the three lower bridge arms is 120°.

[0074] In the charging or discharging circuit, the spatial phase difference between the three windings connected to the conductive three-phase upper (lower) bridge arm is 120°. The spatial phase difference between the currents flowing into (and out of) the three-phase windings is 120°, making the stator magnetic field composed of the three-phase spatially symmetrical windings close to zero (approximately 0 to 0.5T). This effectively suppresses the vibration noise generated by the interaction between the stator magnetic field and the rotor magnetic field when the power battery heating circuit is used to heat the power battery. At the same time, by controlling the synthetic magnetic field of the currents flowing into multiple windings belonging to the same motor to 0 to 0.5T, the motor is prevented from operating, and the problem of rotor heating in the motor is solved, thereby extending the battery self-heating service life.

[0075] In some embodiments, sending a heating signal to the inverter module 220 at a preset frequency may include: determining whether the state of charge value of the battery pack is greater than or equal to a preset threshold; if so, sending a heating signal to the inverter module 220 at the preset frequency.

[0076] The State of Charge (SOC) refers to the ratio of a battery's remaining charge at a specific discharge rate to its rated capacity under the same conditions. SOC is a key parameter of the Battery Management System (BMS) and forms the basis for the vehicle's charge and discharge control strategies and battery balancing. However, due to the inherent structural complexity of lithium-ion batteries, their SOC cannot be directly measured. SOC can only be estimated based on certain external battery characteristics, such as internal resistance, temperature, and current, using characteristic curves or calculation formulas.

[0077] The embodiment of the present application can be applied to the scenario of heating a power battery with a relatively low temperature. For example, it can be applied to a specific scenario in which the temperature of the power battery is raised by heating the power battery to a temperature at which the battery pack can be used normally. Specifically, in the embodiment of the present application, when the SOC of the power battery is greater than a preset threshold, the current flowing through the circuit can be modulated into an AC current, and the AC current is used to generate heat through the internal resistance of the power battery, thereby heating the power battery, which can improve the heating efficiency; when the battery SOC is less than or equal to the preset threshold, that is, when the battery power is insufficient, the DC current is used to generate heat in the winding to heat the power battery, which can reduce power consumption and improve the flexibility of the power battery heating system.

[0078] Optionally, the inverter module 220 can be controlled at the beginning so that the current flowing through the motor circuit is a direct current, and the SOC of the power battery is periodically determined. Once it is determined that the SOC of the power battery is greater than a preset threshold, the inverter module 220 is controlled so that the current flowing through the motor circuit is an alternating current, and the alternating current is used to generate heat through the internal resistance of the power battery, thereby heating the power battery, thereby improving the heating efficiency.

[0079] Specifically, a space vector pulse width modulation (SVPWM) algorithm may be used to modulate the current in the motor winding into direct current or alternating current.

[0080] It should be noted that when DC current flows through the motor windings, the radial electromagnetic force of the motor is reduced, and the eddy current loss of the motor rotor is reduced, thereby reducing the heat generated by the rotor. Therefore, when DC current flows through the motor windings, the heat generated by the motor rotor and the electromagnetic vibration noise are reduced.

[0081] In some embodiments, sending a heating signal to the inverter module 220 at a preset frequency may include the following processing: obtaining the working state of the motor; when the working state of the motor is a non-driving state, sending a heating signal to the inverter module 220 at a preset frequency.

[0082] By judging the working status of the motor, it is possible to prevent the power battery from being heated when the motor is in the driving state, thereby affecting the performance of power devices such as vehicles.

[0083] Furthermore, when the motor is in a non-driving state and the power battery heating system has no faults, a heating signal may be sent to the inverter module 220 .

[0084] It should be noted that, in the embodiment of the present application, a failure in the power battery heating system refers to a failure in any of the power supply module 210, drive module 230, control module 240, inverter module 220, and the thermal circuit. A failure in the thermal circuit includes, but is not limited to, a damaged interconnecting valve and insufficient medium in the thermal circuit.

[0085] Optionally, gear position information and motor speed information can be obtained to determine whether the motor is in a driving or non-driving state. Specifically, if the current gear is determined to be P and the vehicle speed is 0, the motor is in a non-driving state; if the current gear is not P or the vehicle speed is not 0, the motor is in a driving state. Based on the gear position and motor speed information, if either condition is not met, the heating signal is not sent to the motor, preventing the vehicle from heating the power battery during normal driving, which could affect vehicle performance.

[0086] In some embodiments, sending a heating signal to the inverter module 220 at a preset frequency may include: receiving request data sent by a battery management system; if the request data indicates that the power battery meets the heating conditions, sending a heating signal to the inverter module 220 at a preset frequency.

[0087] By receiving the heating request sent by the BMS, the control module can promptly control the power battery heating system to heat the power battery to avoid affecting the use of power devices such as vehicles.

[0088] In some embodiments, sending a heating signal to the inverter module 220 at a preset frequency may include: receiving a control signal sent by a vehicle controller; and if the control signal indicates that the power battery is heated, sending a heating signal to the inverter module 220 at a preset frequency.

[0089] In the embodiment of the present application, the control module 240 may include a vehicle control unit (VCU) and / or a motor control unit (MCU).

[0090] Optionally, when the vehicle controller receives a heating request sent by the BMS, the vehicle controller may send a control signal to the motor controller, which control signal is used to instruct the power battery to be heated, that is, the control signal is used to instruct the motor controller to send a heating signal to the inverter module 220. For example, after receiving the control signal sent by the integrated controller, the motor controller may send a first heating signal to the inverter module 220, and the first heating signal is used to control the inverter module 220 so that a discharge circuit (or charging circuit) is formed between the power supply module 210, the inverter module 220, and the three first windings and the three second windings. After a preset time interval, the motor controller sends a second heating signal to the inverter module 220, and the second heating signal is used to control the inverter module 220 so that a charging circuit (or discharge circuit) is formed between the power supply module 210, the inverter module 220, and the three first windings and the three second windings. The current directions in the charging circuit and the discharge circuit are opposite, and the current flows into the three first windings in turn and then flows out of the three second windings.

[0091] In some embodiments, the power battery heating control method also includes the following processing: determining whether the temperature of the battery pack meets the conditions for stopping heating; the conditions for stopping heating include the battery pack reaching a preset temperature or the temperature rise of the power battery being abnormal; if so, sending a stop heating signal to the inverter module 220, and the stop heating signal causes the inverter module 220 to disconnect the charging circuit or the discharging circuit.

[0092] The preset temperature can be set to a temperature at which the battery pack can operate normally, and can be slightly higher than the lowest temperature at which the battery pack can operate normally, so as to extend the time it takes for the battery pack to reheat. The abnormal temperature rise can be caused by the temperature rising too fast or too slow.

[0093] By setting a stop heating signal, heating can be stopped in time when the temperature rise of the battery pack is abnormal or reaches the normal working temperature, so as to avoid wasting resources and facilitate timely use by users.

[0094] The following will be Figure 2 and Figure 3 Taking the power battery heating circuit shown in as an example, the power battery heating control method of the embodiment of the present application is described in detail. Figure 4 A schematic flow chart of the power battery heating control method is shown in FIG. Figure 4 As shown, the control method includes the following steps:

[0095] In step S601, the BMS collects battery parameters such as the battery pack's temperature, SOC, voltage signal, and current signal.

[0096] S602, the BMS determines whether the heating conditions are met based on various battery parameters. If so, the BMS sends a corresponding heating request to the VCU based on the SOC state, for example, sending the required electric power for heating to a preset temperature to the VCU.

[0097] S603: The BMS or VCU determines whether the battery SOC is greater than a preset threshold.

[0098] S604: If the SOC is greater than the preset threshold, the power battery is heated by utilizing the heat generated by the AC current flowing through the motor circuit.

[0099] S605 , if the SOC is less than or equal to the preset threshold, heat generated by the DC current flowing through the motor circuit is used to heat the power battery.

[0100] After 604 , the VCU reads the current working status of the motor.

[0101] For example, if the motor is in a driving state (i.e., a working state), the VCU sends a driving signal to the motor controller. At this time, the motor controller sends a periodic driving signal to the inverter module 220 to control the upper bridge arm and the lower bridge arm of the bridge arm 331 to 336 to switch the switch on according to the periodic driving signal sent by the motor controller, thereby realizing the inverter control of the battery current. If the motor is in a non-driving state, the VCU sends a control signal to the motor controller. At this time, the motor controller sends a first heating signal and a second heating signal to the inverter module 220, alternately controlling the upper bridge arm of the bridge arm 331 to 333 and the lower bridge arm of the bridge arm 334 to 336, and the lower bridge arm of the bridge arm 331 to 333 and the upper bridge arm of the bridge arm 334 to 336 to keep the switch on and off at the same time.

[0102] Specifically, when the upper bridge arms 3311, 3321, and 3331 of the bridge arms 331-333 and the lower bridge arms 3342, 3352, and 3362 of the bridge arms 334-336 are turned on, and the lower bridge arms 3312, 3322, and 3332 of the bridge arms 331-333 and the upper bridge arms 3341, 3351, and 3361 of the bridge arms 334-336 are turned off, the battery 350 is discharged, and the discharge circuit is: 350(+)→(3311 / 3321 / 3331)→(311 / 312 / 313)→(314 / 315 / 316)→(3342 / 3352 / 3362)→350(-). The current state is as follows: Figure 2When the lower bridge arms 3312, 3322, and 3332 of the bridge arms 331-333 and the upper bridge arms 3341, 3351, and 3361 of the bridge arms 334-336 are turned on, and the upper bridge arms 3311, 3321, and 3331 of the bridge arms 331-333 and the lower bridge arms 3342, 3352, and 3362 of the bridge arms 334-336 are turned off, the battery 350 is charged, and the charging circuit is: 350(-)→(3312 / 3322 / 3332)→(311 / 312 / 313)→(314 / 315 / 316)→(3341 / 3351 / 3361)→350(+). The current state is as follows: Figure 3 shown.

[0103] S606, the BMS determines whether the battery pack temperature is abnormal. If so, it sends a temperature rise abnormality message to the VCU. The VCU forwards the temperature rise abnormality message to the motor controller and stops heating.

[0104] S607: If S606 determines that the temperature rise is normal, the BMS determines whether the battery pack temperature meets the requirements. If so, the VCU forwards the stop heating information to the motor controller to stop heating; otherwise, repeat S604 / S605 and S606.

[0105] The power battery heating control method provided in the embodiment of the present application controls the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit and the lower bridge arms of the same phase arms in the remaining bridge arms to be turned on through the control module 240, so that the power supply module 210, the inverter module 220 and the drive module 230 form an alternating charging circuit and a discharging circuit to charge and discharge the battery pack. In this way, a cyclic charging and discharging circuit can be formed, and the battery pack can be continuously heated until the temperature of the battery pack reaches the normal operating temperature, so that the power battery can be used normally in a low temperature environment, avoiding the limitation of the charging and discharging capacity of the power battery, and greatly improving the customer's winter car experience.

[0106] Based on the same concept as the above-mentioned power battery heating circuit, an embodiment of the present application also provides a power battery heating system, which includes a heating controller and the above-mentioned power battery heating circuit; the heating controller is used to send instructions to the power battery heating circuit to control the power battery heating circuit to form an alternating charging circuit and a discharging circuit.

[0107] Specifically, the heating controller can be the aforementioned vehicle controller, and the control module 240 of the power battery heating circuit can be a motor controller. It should be noted that the heating controller can also be a separate controller specifically configured to send instructions to the power battery heating circuit to control the power battery heating circuit to form alternating charging and discharging circuits, which is not specifically limited in this embodiment.

[0108] The power battery heating system provided in the embodiment of the present application controls the power battery heating circuit through a control module to form an alternating charging circuit and a discharging circuit to charge and discharge the battery pack. In this way, a cyclic charging and discharging circuit can be formed, and the battery pack can be continuously heated until the temperature of the battery pack reaches the normal operating temperature, so that the power battery can be used normally in a low temperature environment, avoiding the limitation of the charging and discharging capacity of the power battery, and greatly improving the customer's winter car experience.

[0109] Based on the same concept as the above-mentioned power battery heating circuit, an embodiment of the present application further provides an electrical device, including the above-mentioned power battery heating system.

[0110] The power battery heating system of the electrical equipment provided in the embodiment of the present application can control the power battery heating circuit through the control module to form an alternating charging circuit and a discharging circuit to charge and discharge the battery pack. In this way, a cyclic charging and discharging charging and discharging circuit can be formed, and the battery pack can be continuously heated until the temperature of the battery pack reaches the normal operating temperature, so that the power battery can be used normally in a low temperature environment, avoiding the limitation of the charging and discharging capacity of the power battery, and greatly improving the customer's winter car experience.

[0111] Optionally, the electrical device may be a powered vehicle.

[0112] Figure 5 FIG. 2 shows a schematic block diagram of the control module 240 of the power battery heating circuit according to an embodiment of the present application. Figure 5 As shown, the control module 240 includes a processor 2410. Optionally, the control module 240 also includes a memory 2420, wherein the memory 2420 is used to store instructions, and the processor 2410 is used to read the instructions and execute the methods of the various embodiments of the present application based on the instructions.

[0113] 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.

[0114] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0115] 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 units is only 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.

[0116] Units described as separate components may or may not be physically separate, and 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.

[0117] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0118] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program code.

[0119] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A power battery heating circuit, characterized in that: include: a power supply module, comprising at least one battery pack; an inverter module connected to the power supply module, comprising an M-phase bridge arm circuit, wherein the bridge arm circuit is connected in parallel with the battery pack, where M is an even multiple of three; A drive module includes a motor having M windings, wherein the motor includes a six-phase symmetrical motor, and the M windings are respectively connected to the M-phase bridge arms of the bridge arm circuit in a one-to-one correspondence; a control module connected to the bridge arm circuit and configured to control the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit, and the lower bridge arms of the same phase in the remaining bridge arms, to be turned on, so that the power supply module, the inverter module, and the drive module form an alternating charging circuit and a discharging circuit; in the charging circuit or the discharging circuit, the spatial phase difference between the three windings respectively connected to the three-phase upper bridge arms that are turned on is 120 degrees, and the spatial phase difference between the three windings respectively connected to the three lower bridge arms that are turned on is also 120 degrees; The control module is specifically configured to modulate the current flowing through the circuit into an alternating current when the state of charge (SOC) of the power battery is greater than a preset threshold, and utilize the alternating current to generate heat through the internal resistance of the power battery to heat the power battery; and utilize direct current to generate heat in the winding to heat the power battery when the SOC of the power battery is less than or equal to the preset threshold.

2. A power battery heating control method, characterized in that: Applied to the power battery heating circuit according to claim 1, the method comprises: An enable signal is sent to control the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit, as well as the lower bridge arms of the same phases in the remaining bridge arms, to be turned on, so that the power supply module, inverter module and drive module of the battery heating circuit form an alternating charging circuit and a discharging circuit.

3. The power battery heating control method according to claim 2, characterized in that: A heating signal is sent to the inverter module at a preset frequency to control the inverter module to alternately switch the charging circuit and the discharging circuit.

4. The power battery heating control method according to claim 3, characterized in that: Sending a heating signal to the inverter module at a preset frequency includes: sending a first heating signal and a second heating signal alternately to the inverter module at a preset frequency; The first heating signal turns on the upper bridge arms of at least three-phase bridge arms in the bridge arm circuit, and the lower bridge arms of the same phases in the remaining bridge arms, so that the power supply module, the inverter module, and the drive module of the battery heating circuit form a charging loop; The second heating signal turns on the lower bridge arms of the at least three-phase bridge arms and the upper bridge arms of the remaining bridge arms with the same phase number, so that the power supply module, the inverter module and the drive module of the battery heating circuit form a discharge loop.

5. The power battery heating control method according to claim 4, characterized in that: The motor of the driving module includes a six-phase symmetrical motor; The first heating signal turns on the upper bridge arm of three phases in the six-phase bridge arm circuit and the lower bridge arm of the other three phases, so that the power supply module, the inverter module, and the drive module of the battery heating circuit form a charging circuit; The second heating signal turns on the lower bridge arm of the three-phase bridge arm and the upper bridge arm of the other three-phase bridge arm in the six-phase bridge arm circuit, so that the power supply module, the inverter module, and the drive module of the battery heating circuit form a discharge loop; In the charging circuit or the discharging circuit, the spatial phase difference between the three windings respectively connected to the three-phase upper bridge arms that are turned on is 120 degrees, and the spatial phase difference between the three windings respectively connected to the three lower bridge arms that are turned on is 120 degrees.

6. The power battery heating control method according to any one of claims 3 to 5, characterized in that: The sending of a heating signal to the inverter module at a preset frequency includes: determining whether a state of charge value of the battery pack is greater than or equal to a preset threshold; If so, a heating signal is sent to the inverter module at a preset frequency.

7. The battery heating control method according to any one of claims 3 to 5, characterized in that: The sending of a heating signal to the inverter module at a preset frequency includes: Obtaining the working status of the motor; If the working state of the motor is a non-driving state, a heating signal is sent to the inverter module at a preset frequency.

8. The battery heating control method according to any one of claims 3 to 5, characterized in that: The sending of a heating signal to the inverter module at a preset frequency includes: receiving a control signal sent by a vehicle controller; If the control signal indicates that the power battery is to be heated, a heating signal is sent to the inverter module at a preset frequency.

9. The battery heating control method according to any one of claims 3 to 5, characterized in that: The sending of a heating signal to the inverter module at a preset frequency includes: Receive request data sent by the battery management system; If the request data indicates that the power battery meets the heating condition, a heating signal is sent to the inverter module at a preset frequency.

10. The battery heating control method according to any one of claims 3 to 5, characterized in that: The method further comprises: determining whether the temperature of the battery pack satisfies a heating stop condition; the heating stop condition includes the battery pack reaching a preset temperature or the temperature rise of the power battery being abnormal; If so, a stop heating signal is sent to the inverter module, and the stop heating signal causes the inverter module to disconnect the charging circuit or the discharging circuit.

11. A power battery heating system, characterized in that: The system includes a heating controller and the power battery heating circuit according to claim 1; the heating controller is used to send instructions to the power battery heating circuit to control the power battery heating circuit to form an alternating charging circuit and a discharging circuit.

12. An electrical device, characterized in that: It includes the power battery heating system as claimed in claim 11.

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