Battery heating method, circuit, battery apparatus, electrical device and energy storage device

Abstract

The present application provides a battery heating method, a circuit, a battery apparatus, an electrical device, and an energy storage device, and belongs to the technical field of batteries. The battery heating method comprises: acquiring the temperature of a battery; and, in response to the temperature of the battery being less than a preset temperature, controlling, by means of a switch circuit, the battery to be in a heating stage so as to heat the battery, the heating stage comprising a first heating stage, and the first heating stage comprising: by means of the switch circuit, repeatedly executing N1 times the step of first battery units charging a first energy storage circuit and the first energy storage circuit charging second battery units, N1 being a positive integer greater than or equal to 1. By controlling the switch circuit, using the charging and discharging of battery packs can heat each of the battery packs connected in parallel.

Description

Battery heating methods, circuits, battery devices, electrical equipment, and energy storage devices

[0001] Cross-referencing

[0002] This application incorporates Chinese Patent Application No. 202411726099.3, filed on November 28, 2024, entitled “Battery Heating Method, Circuit, Battery Device, Electrical Equipment and Energy Storage Device”, which is incorporated herein by reference in its entirety. Technical Field

[0003] This application relates to the field of battery technology, and in particular to a battery heating method, circuit, battery device, electrical equipment, and energy storage device. Background Technology

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0005] In low-temperature environments, battery charging efficiency is low. Therefore, how to improve battery charging efficiency in low-temperature environments is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] This application aims to at least solve one of the technical problems existing in the background art. Therefore, one object of this application is to provide a battery heating method, circuit, battery device, electrical appliance, and energy storage device to improve the charging efficiency of batteries in low-temperature environments.

[0007] An embodiment of the first aspect of this application provides a battery heating method. The battery includes multiple battery packs connected in parallel. Each battery pack includes a first battery cell and a second battery cell connected in series. A first terminal of a switching circuit is connected to the positive terminal of each battery pack, and a second terminal of the switching circuit is connected to the negative terminal of each battery pack. A first terminal of a first energy storage circuit is connected to the switching circuit, and a second terminal of the first energy storage circuit is connected to the midpoint between the first and second battery cells of each battery pack. The battery heating method includes: acquiring the temperature of the battery. In response to the battery temperature being lower than a preset temperature, the switching circuit controls the battery to enter a heating phase to heat the battery. The heating phase includes a first heating phase, which includes: repeatedly performing the steps of the first battery cell charging the first energy storage circuit and the first energy storage circuit charging the second battery cell N1 times via the switching circuit, where N1 is a positive integer greater than or equal to 1.

[0008] In the technical solution of this application embodiment, by controlling the switching circuit and utilizing the charging and discharging of the battery pack, each of the parallel battery packs can be heated. During the first heating phase, the steps of the first battery cell charging the first energy storage circuit and the first energy storage circuit charging the second battery cell are repeated N1 times, allowing the first battery cell to maintain a longer discharge time and the second battery cell to maintain a longer charging time, thus improving heating efficiency. Compared to heat transfer heating methods, this application has higher heating efficiency and more uniform heating, resulting in more uniform internal and external temperatures within the battery.

[0009] In some embodiments, a first terminal of the switching circuit is connected to a first connection point, and the positive terminal of each battery pack is connected to the first connection point via a first switch. A second terminal of the first energy storage circuit is connected to a second connection point, and the midpoint between the first and second battery cells of each battery pack is connected to the second connection point via a second switch. Controlling the battery to be in a heating phase includes controlling multiple battery packs to be independently in a heating phase to heat the battery via the first and second switches. This effectively utilizes the heating current, thereby increasing the heating rate.

[0010] In some embodiments, controlling multiple battery packs to independently enter a heating phase to heat the batteries via a first switch and a second switch includes sequentially performing a heating step on each battery pack. The heating step includes a first step and a second step performed sequentially. The first step includes controlling the first switch and the corresponding second switch to be in a closed state. The second step includes controlling the first switch and the corresponding second switch to be in an open state. This ensures that only one battery pack is heated at a time, thereby effectively utilizing the heating current and increasing the heating rate.

[0011] In some embodiments, a second energy storage circuit is connected in parallel across the two ends of the battery. The first end of the second energy storage circuit is connected to the positive terminal of each battery pack, and the second end is connected to the negative terminal of each battery pack. The first heating stage further includes: repeatedly performing the steps of charging the second energy storage circuit from the first battery cell and charging the second battery cell from the second energy storage circuit N2 times via a switching circuit. Here, N2 is a positive integer greater than or equal to 1. The transfer of a portion of the electrical energy from the first battery cell to the second battery cell via the second energy storage circuit improves the energy transfer efficiency, thereby further enhancing the battery's heating efficiency.

[0012] In some embodiments, the first heating stage further includes: simultaneously charging the second energy storage circuit from the first battery cell and charging the second battery cell from the first energy storage circuit via a switching circuit; and / or simultaneously charging the second battery cell from the second energy storage circuit and charging the first energy storage circuit from the first battery cell via a switching circuit, so that current always flows through the first battery cell and the second battery cell.

[0013] In some embodiments, the heating phase further includes a second heating phase. The second heating phase includes: repeatedly performing the steps of the second battery cell charging the first energy storage circuit and the first energy storage circuit charging the first battery cell N3 times via a switching circuit, where N3 is a positive integer greater than or equal to 1. This utilizes energy exchange between the first and second battery cells to achieve battery heating while maintaining energy balance between the first and second battery cells.

[0014] In some embodiments, the battery heating method further includes controlling the battery to sequentially enter a first heating stage and a second heating stage. While heating the battery, the balance between the first battery cell and the second battery cell is maintained.

[0015] In some embodiments, a second energy storage circuit is connected in parallel across the two ends of the battery. The first end of the second energy storage circuit is connected to the positive terminal of each battery pack, and the second energy storage circuit is connected to the negative terminal of each battery pack. The second heating stage further includes: repeatedly performing the steps of charging the second energy storage circuit from the second battery cell and charging the first battery cell from the second energy storage circuit N4 times via a switching circuit, where N4 is a positive integer greater than or equal to 1. The transfer of a portion of the electrical energy from the second battery cell to the first battery cell via the second energy storage circuit improves the energy transfer efficiency, thereby further enhancing the battery's heating efficiency.

[0016] In some embodiments, the second heating stage further includes: simultaneously charging the second energy storage circuit from the second battery cell and charging the first energy storage circuit from the first battery cell via a switching circuit; and / or simultaneously charging the first battery cell from the second energy storage circuit and charging the first energy storage circuit from the second battery cell via a switching circuit. This ensures that current always flows through the first battery cell and the second battery cell.

[0017] In some embodiments, the switching circuit includes bridge arms. The bridge arms include an upper bridge arm and a lower bridge arm connected in series. The upper bridge arm is connected to the positive terminal of each battery pack, and the lower bridge arm is connected to the negative terminal of each battery pack. A first terminal of the first energy storage circuit is connected between the upper and lower bridge arms. In the battery heating method of the above embodiments, the step of repeatedly charging the first energy storage circuit with the first battery cell and charging the second battery cell with the first energy storage circuit N1 times via the switching circuit includes: sequentially and alternately performing a third step and a fourth step. The third step includes controlling the upper bridge arm to be on and the lower bridge arm to be off. The fourth step includes controlling the lower bridge arm to be on and the upper bridge arm to be off. By controlling the alternating on and off of the upper and lower bridge arms, energy transfer from the first battery cell to the second battery cell can be achieved.

[0018] In some embodiments, the heating stage further includes a second heating stage, which includes: repeatedly performing the steps of the second battery cell charging the first energy storage circuit and the first energy storage circuit charging the first battery cell N3 times via a switching circuit, where N3 is a positive integer greater than or equal to 1. Repeating the steps of the second battery cell charging the first energy storage circuit and the first energy storage circuit charging the first battery cell N3 times via a switching circuit includes: sequentially and alternately performing a fourth step and a third step. Energy transfer from the second battery cell to the first battery cell can be achieved by controlling the alternating conduction of the upper and lower bridge arms.

[0019] In some embodiments, the battery heating method further includes: after the battery is in a heating phase to heat the battery, controlling all equalization branches to be in a conductive state. By setting the equalization branches, equalization is performed on each first battery cell and each second battery cell after the battery heating is completed.

[0020] In some embodiments, a balancing branch is provided between each pair of adjacent battery packs. In each pair of adjacent battery packs, a first end of the balancing branch is connected to the midpoint between the first and second battery cells of one pack, and a second end of the balancing branch is connected to the midpoint between the first and second battery cells of the other pack. The balancing branch includes a switch and a resistive load connected in series. Controlling the battery to be in the heating phase includes controlling all switches to be in the open state. After the battery is in the heating phase, controlling all balancing branches to be in the conducting state includes controlling all switches to be in the closed state. By setting switches and resistive loads, the problem of large current caused by large voltage differences can be alleviated while simultaneously achieving the switching of the balancing branches.

[0021] An embodiment of the second aspect of this application provides a battery heating circuit. The battery includes multiple battery packs connected in parallel, each battery pack including a first battery cell and a second battery cell connected in series. The battery heating circuit includes a switching circuit and a first energy storage circuit. A first terminal of the switching circuit is connected to the positive terminal of each battery pack, and a second terminal of the switching circuit is connected to the negative terminal of each battery pack. A first terminal of the first energy storage circuit is connected to the switching circuit, and a second terminal of the first energy storage circuit is connected to the midpoint between the first and second battery cells of each battery pack. The switching circuit is configured to connect the first battery cell to the first energy storage circuit to form a first heating circuit, and to connect the second battery cell to the first energy storage circuit to form a second heating circuit.

[0022] In some embodiments, a first terminal of the switching circuit is connected to a first connection point, and the positive terminal of each battery pack is connected to the first connection point via a first switch. A second terminal of the first energy storage circuit is connected to a second connection point, and the midpoint between the first and second battery cells of each battery pack is connected to the second connection point via a second switch. By controlling the first and second switches, only one battery pack can be heated at a time during the heating phase, thereby effectively utilizing the heating current and increasing the heating rate.

[0023] In some embodiments, the switching circuit includes at least one switching branch, with its two ends connected to a first connection point and the negative terminal of each battery pack, respectively. The switching branch includes a first switching element and a second switching element connected in series, with the midpoint between the first and second switching elements connected to a first terminal of the first energy storage circuit. Different heating circuits can be formed and switched between them using the first and second switching elements.

[0024] In some embodiments, there are multiple switching branches connected in parallel. The first energy storage circuit includes multiple first energy storage elements connected in parallel. These multiple first energy storage elements are connected one-to-one with the midpoint between the first and second switching elements of the multiple switching branches. By setting multiple corresponding first energy storage elements and multiple switching branches, multiple first heating circuits or multiple second heating circuits can be formed, thereby improving the heating efficiency of the battery.

[0025] In some embodiments, the first energy storage circuit further includes a second energy storage element, which is connected in series with a plurality of first energy storage elements that are connected in parallel. By adding a second energy storage element, the heating efficiency and reliability are improved.

[0026] In some embodiments, the first energy storage element and the second energy storage element are inductors. By configuring the first energy storage element and the second energy storage element as inductors, energy storage and release are achieved through inductance.

[0027] In some embodiments, the first energy storage circuit includes three first inductors connected in parallel, which are multiplexed from the three-phase inductors in the motor. By multiplexing the three-phase inductors in the motor to form the first energy storage circuit, the overall cost is reduced.

[0028] In some embodiments, the switching branch is a bridge arm, which includes an upper bridge arm and a lower bridge arm connected in series. The upper bridge arm is connected to the positive terminal of each battery pack, and the lower bridge arm is connected to the negative terminal of each battery pack. A first terminal of the first energy storage circuit is connected between the upper and lower bridge arms. The switching element of the upper bridge arm serves as a first switching element, and the switching element of the lower bridge arm serves as a second switching element. The bridge arm has a simple structure and is easy to control, which simplifies the circuit while improving the reliability of battery heating control.

[0029] In some embodiments, the battery heating circuit further includes a balancing branch. A balancing branch is provided between each pair of adjacent battery packs. In each pair of adjacent battery packs, a first end of the balancing branch is connected to the midpoint between the first and second battery cells of one pack, and a second end of the balancing branch is connected to the midpoint between the first and second battery cells of the other pack. By providing the balancing branch, the individual first and second battery cells are balanced after the battery heating process is complete.

[0030] In some embodiments, the battery heating circuit further includes a second energy storage circuit, wherein a first terminal of the second energy storage circuit is connected to the positive terminal of each battery pack, and a second terminal of the second energy storage circuit is connected to the negative terminal of each battery pack. By adding the second energy storage circuit, the energy transfer efficiency is improved, thereby further improving the battery heating efficiency. An embodiment of the third aspect of this application provides a battery device including a battery and the battery heating circuit of any of the above embodiments. The battery heating circuit is connected to the battery and used to heat the battery.

[0031] In some embodiments, the battery includes multiple battery packs connected in parallel, each battery pack including a first battery cell and a second battery cell connected in series.

[0032] An embodiment of the fourth aspect of this application provides an electrical device including a battery device as described in the above embodiments, the battery device being used to provide electrical energy.

[0033] An embodiment of the fifth aspect of this application provides an energy storage device, including a battery device as described in the above embodiments.

[0034] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0035] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0036] Figure 1 is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0037] Figure 2 is a schematic diagram of the battery heating circuit of some embodiments of this application;

[0038] Figure 3 is one of the current path diagrams of the battery heating circuit in the first heating stage of some embodiments of this application;

[0039] Figure 4 is a second schematic diagram of the current path of the battery heating circuit in the first heating stage of some embodiments of this application;

[0040] Figure 5 is a schematic flowchart of a battery heating method according to some embodiments of this application;

[0041] Figure 6 is a schematic diagram of the current path of the battery heating circuit in the first heating stage of some embodiments of this application;

[0042] Figure 7 is a fourth schematic diagram of the current path of the battery heating circuit in the first heating stage of some embodiments of this application;

[0043] Figure 8 is one of the current path diagrams of the battery heating circuit in the second heating stage of some embodiments of this application;

[0044] Figure 9 is a second schematic diagram of the current path of the battery heating circuit in the second heating stage according to some embodiments of this application;

[0045] Figure 10 is a schematic diagram of the current path of the battery heating circuit in the second heating stage of some embodiments of this application;

[0046] Figure 11 is a fourth schematic diagram of the current path of the battery heating circuit in the second heating stage according to some embodiments of this application.

[0047] Explanation of reference numerals in the attached drawings: 1000, vehicle; 100, battery; 200, vehicle controller; 300, motor; 10, battery pack; 11, first battery cell; 12, second battery cell; 20, switching circuit; 21, switching branch; 30, first energy storage circuit; 40, balancing branch; 50, second energy storage circuit. Detailed Implementation

[0048] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0050] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0051] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0052] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0053] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0054] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0055] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0056] Currently, judging from market trends, battery applications are becoming increasingly widespread. Batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of battery applications, market demand is also constantly increasing.

[0057] In low-temperature environments, the fluidity of the battery electrolyte decreases, which slows down the movement of ions and results in lower charging efficiency, leading to longer charging times and thus affecting battery performance.

[0058] In some cases, battery charging efficiency can be improved by increasing the battery temperature. This can be achieved by using an external heating device, such as a thermistor (Positive Temperature Coefficient, PTC). However, this heating method relies on heat transfer, resulting in relatively low efficiency and uneven temperature distribution between the battery's exterior and interior.

[0059] Based on the above considerations, this application provides a battery heating method, circuit, battery device, electrical device, and energy storage device. The battery heating method includes: acquiring the temperature of the battery. In response to the battery temperature being lower than a preset temperature, the battery is controlled to enter a heating stage via a switching circuit to heat the battery. The heating stage includes a first heating stage, which includes: repeatedly executing the steps of charging a first energy storage circuit with a first battery cell and charging a second battery cell with the first energy storage circuit N1 times via the switching circuit, where N1 is a positive integer greater than or equal to 1.

[0060] By controlling the switching circuit and utilizing the charging and discharging of the battery packs, each of the parallel battery packs can be heated. During the first heating phase, the steps of the first battery cell charging the first energy storage circuit and the first energy storage circuit charging the second battery cell are repeated N1 times. This allows the first battery cell to maintain a longer discharge time and the second battery cell to maintain a longer charging time, thus improving heating efficiency. Compared to heat transfer heating methods, this application offers higher heating efficiency and more uniform heating, resulting in more uniform internal and external temperatures within the battery.

[0061] The battery heating method disclosed in this application can be used, but is not limited to, for heating batteries in electrical equipment such as vehicles, ships, or aircraft, as well as in energy storage devices. This helps improve the charging efficiency of batteries in low-temperature environments.

[0062] Electrical devices can include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0063] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0064] Please refer to Figure 1, which is a schematic diagram of the vehicle structure provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a vehicle controller 200 and a motor 300. The vehicle controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0065] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0066] Referring to Figures 2 to 5, Figure 2 is a structural schematic diagram of a battery heating circuit according to some embodiments of this application; Figure 3 is a schematic diagram of the current path of a battery heating circuit in the first heating stage according to some embodiments of this application; Figure 4 is a schematic diagram of the current path of a battery heating circuit in the first heating stage according to some embodiments of this application; and Figure 5 is a flowchart of a battery heating method according to some embodiments of this application. In Figures 3 and 4, solid lines with arrows indicate the direction of current flow.

[0067] This application provides a battery heating method. The battery includes multiple battery packs 10 connected in parallel. Each battery pack 10 includes a first battery cell 11 and a second battery cell 12 connected in series. A first terminal of a switching circuit 20 is connected to the positive terminal of each battery pack 10, and a second terminal of the switching circuit 20 is connected to the negative terminal of each battery pack 10. A first terminal of a first energy storage circuit 30 is connected to the switching circuit 20, and a second terminal of the first energy storage circuit 30 is connected to the midpoint between the first battery cell 11 and the second battery cell 12 of each battery pack 10.

[0068] Battery heating methods include:

[0069] Step 110: Obtain the battery temperature.

[0070] Step 120: In response to the battery temperature being lower than a preset temperature, the battery is controlled to enter a heating stage via the switching circuit 20 to heat the battery. The heating stage includes a first heating stage, which includes: repeatedly executing the steps of the first battery cell 11 charging the first energy storage circuit 30 and the first energy storage circuit 30 charging the second battery cell 12 N1 times via the switching circuit 20, where N1 is a positive integer greater than or equal to 1.

[0071] Each battery pack 10 includes a first battery cell 11 and a second battery cell 12 connected in series. The series connection can be such that the positive terminal of the first battery cell 11 is connected to the negative terminal of the second battery cell 12, or vice versa. In some examples, as shown in Figures 2 to 4, the negative terminal of the first battery cell 11 is connected to the positive terminal of the second battery cell 12. The positive terminal of the battery pack 10 is the positive terminal of the first battery cell 11, and the negative terminal of the battery pack 10 is the negative terminal of the second battery cell 12. The midpoint between the first battery cell 11 and the second battery cell 12 is the connection point between the negative terminal of the first battery cell 11 and the positive terminal of the second battery cell 12.

[0072] The switching circuit 20 is a circuit that controls the on / off state of current. Specifically, it can control the on / off state of the switching element to realize the conduction or disconnection of current in the circuit.

[0073] The first energy storage circuit 30 is a circuit that stores energy and releases it when needed. In some examples, external electrical energy is input to the first energy storage circuit 30 for storage, and the stored energy is released externally in the form of electrical energy when needed. The first energy storage circuit 30 includes energy storage elements, which can be capacitors or inductors.

[0074] The switching circuit 20 may include a first node C1, a second node C2, and a third node C3 interconnected by switching elements. The first node C1 may be connected to the positive terminal of the battery pack 10, the second node C2 may be connected to the negative terminal of the battery pack 10, and the third node C3 may be connected to the first terminal of the first energy storage circuit 30. The first node C1 may be a node between the switching circuit 20 and the positive terminal of the battery pack 10, the second node C2 may be a node between the switching circuit 20 and the negative terminal of the battery pack 10, and the third node C3 may be a node between the first energy storage circuit 30 and the switching circuit 20.

[0075] The first node C1, the second node C2, and the third node C3 are interconnected via a switching element. That is, any two of the first node C1, the second node C2, and the third node C3 can be connected via a switching element. Through the switching circuit 20, the first energy storage circuit 30 can form a circuit with either the first battery unit 11 or the second battery unit 12. For example, the positive terminal of the first battery unit 11 is connected to the first node C1, and the negative terminal of the second battery unit 12 is connected to the second node C2. When the first node C1 and the third node C3 are both connected, the first energy storage circuit 30 and the first battery unit 11 form a first heating circuit. When the second node C2 and the third node C3 are both connected, the first energy storage circuit 30 and the second battery unit 12 form a second heating circuit.

[0076] The controller can be the main implementer of the battery heating method. The controller changes the conduction mode of the current in the battery heating circuit by controlling the switching elements in the switching circuit 20, thereby realizing the switching between the first heating circuit and the second heating circuit. The switching process between the first heating circuit and the second heating circuit forms the first heating stage. In the first heating stage, energy exchange is realized by means of the first energy storage circuit 30, thereby heating the first battery cell 11 and the second battery cell 12.

[0077] In some embodiments, the controller may include, but is not limited to, the microcontroller unit (MCU) of a vehicle, or the controller in the battery management system (BMS) of a battery.

[0078] In some embodiments, a temperature sensor may also be provided in the battery to obtain the temperature of the first battery cell 11 and the second battery cell 12 of each battery pack 10. The temperature sensor is communicatively connected to the BMS. The controller in the BMS can receive the temperature information of the first battery cell 11 and the second battery cell 12 detected by the temperature sensor, and in response to the temperature of at least one of the first battery cell 11 and the second battery cell 12 of all battery packs 10 being lower than a preset temperature, control the switching circuit 20 to switch between the first heating circuit and the second heating circuit, thereby forming a first heating stage.

[0079] The preset temperature can be adjusted according to the battery type. The method to set the preset temperature is to test the relationship between the battery's charging rate and temperature in advance. When the temperature is lower than a certain value or a certain range, the charging rate will decrease significantly. This value can then be determined as the preset temperature.

[0080] In the first heating stage, as shown in Figure 3, the first battery cell 11 and the first energy storage circuit 30 form a first heating circuit by controlling the switching circuit 20. The first battery cell 11 charges the first energy storage circuit 30, which stores energy. Heating of the first battery cell 11 is achieved through the discharge of the first battery cell 11. As shown in Figure 4, the second battery cell 12 and the first energy storage circuit 30 form a second heating circuit. Since the first energy storage circuit 30 stores energy in the first heating circuit, it can charge the second battery cell 12 in the second heating circuit, thus heating the second battery cell 12 through charging. In other words, in the first heating stage, the first energy storage circuit 30 transfers a portion of the electrical energy from the first battery cell 11 to the second battery cell 12.

[0081] Repeating the steps of charging the first battery cell 11 for the first energy storage circuit 30 and charging the second battery cell 12 for the first energy storage circuit 30 N1 times means that the electrical energy input and output in the first energy storage circuit 30 are each performed N1 times. This process can be repeated multiple times until the temperature of the first battery cell 11 and the second battery cell 12 of all battery packs 10 is greater than the preset temperature. The number of times this process is performed is N1, and the value of N1 can be 1, 2, 3, or more than 3.

[0082] Repeated execution allows the first battery cell 11 to maintain a longer discharge time and the second battery cell 12 to maintain a longer charging time. Compared to executing it only once, this reduces the rate of change of current flowing through the first energy storage circuit 30, thereby reducing the current frequency, decreasing current ripple, and improving the high-frequency whistling problem of the battery heating circuit. This achieves low-frequency heating of the battery, thus improving the heating efficiency.

[0083] The specific process for different execution counts is explained below.

[0084] In the case of execution once, the input and output of electrical energy in the first energy storage circuit 30 are performed once each. The whole process is as follows: first, the first heating circuit is turned on, and the first energy storage circuit 30 receives the input of electrical energy. Then, it switches to the second heating circuit, and the first energy storage circuit 30 outputs electrical energy.

[0085] In the case of execution twice, the input and output of electrical energy in the first energy storage circuit 30 are performed twice each. The whole process is as follows: first, the first heating circuit is turned on, and the first energy storage circuit 30 receives the input of electrical energy. Then, it switches to the second heating circuit, and the first energy storage circuit 30 outputs electrical energy. Then, it switches back to the first heating circuit, and the first energy storage circuit 30 receives the input of electrical energy. Finally, it switches back to the second heating circuit, and the first energy storage circuit 30 outputs electrical energy.

[0086] The process of executing the procedure three or more times will be repeated in the same manner, and will not be elaborated further here.

[0087] By controlling the switching circuit 20, the charging and discharging of the battery packs 10 can heat each of the parallel battery packs 10. During the first heating phase, the steps of the first battery cell 11 charging the first energy storage circuit 30 and the first energy storage circuit 30 charging the second battery cell 12 are repeated N1 times. This allows the first battery cell 11 to maintain a longer discharge time and the second battery cell 12 to maintain a longer charging time, thus improving heating efficiency. Compared to heat transfer heating methods, this application offers higher heating efficiency and more uniform heating, resulting in more uniform internal and external temperatures within the battery.

[0088] Referring to Figures 2 to 4, according to some embodiments of this application, the first terminal of the switching circuit 20 is connected to the first connection point P1, and the positive terminal of each battery pack 10 is connected to the first connection point P1 through a first switch (K4, K5, K6). The second terminal of the first energy storage circuit 30 is connected to the second connection point P2, and the midpoint between the first battery cell 11 and the second battery cell 12 of each battery pack 10 is connected to the second connection point P2 through a second switch (K9, K8, K7). Controlling the battery to be in the heating stage to heat the battery includes controlling multiple battery packs to be independently in the heating stage to heat the battery through the first switch (K4, K5, K6) and the second switch (K9, K8, K7).

[0089] The first switch (K4, K5, K6) is a component used to control the on / off state between the positive terminal of the battery pack 10 and the first connection point P1. The second switch (K9, K8, K7) is a component used to control the on / off state between the midpoint between the first battery cell 11 and the second battery cell 12 and the second connection point P2.

[0090] Each battery pack 10 corresponds to one first switch and one second switch, meaning multiple first switches and second switches are configured in a one-to-one correspondence. For example, first switch K4 corresponds to second switch K9, first switch K5 corresponds to second switch K8, and first switch K6 corresponds to second switch K7. By closing the first switch and the corresponding second switch, the corresponding battery pack 10 is connected to the switching circuit 20 and the first energy storage circuit 30, allowing heating of the battery pack 10. By opening the first switch and the corresponding second switch, the corresponding battery pack 10 is disconnected from the switching circuit 20 and the first energy storage circuit 30, preventing heating of the battery pack.

[0091] Controlling multiple battery packs 10 to independently operate in the heating phase for battery heating can be understood as follows: each battery pack 10 can be heated sequentially in a certain order. That is, during the heating phase, only one battery pack 10 is heated at a time, meaning only one battery pack 10 is connected to the switching circuit 20 and the first energy storage circuit 30. While one battery pack 10 is in the heating phase, the remaining battery packs 10 are in the non-heating phase, until all battery packs 10 have completed heating.

[0092] Since only one battery pack 10 is heated at a time, the heating current will only flow in one battery pack 10 and will not be distributed to other battery packs 10, thus increasing the heating rate.

[0093] By controlling the first and second switches, the corresponding battery pack 10 can be connected or disconnected from the switching circuit 20 and the first energy storage circuit 30, thereby controlling multiple battery packs 10 to be independently in the heating stage, thus effectively utilizing the heating current and increasing the heating rate.

[0094] Referring to Figures 2 to 4, according to some embodiments of this application, controlling multiple battery packs 10 to independently enter a heating phase to heat the batteries via a first switch (K4, K5, K6) and a second switch (K9, K8, K7) includes sequentially performing a heating step on each battery pack 10. The heating step includes a first step and a second step performed sequentially. The first step includes controlling the first switch and the corresponding second switch to be in a closed state. The second step includes controlling the first switch and the corresponding second switch to be in an open state.

[0095] The heating steps are performed on each battery pack 10 in sequence. It can be understood that the heating steps can be performed on the first battery pack 10 in a certain order, then on the second battery pack 10, until all battery packs 10 have completed the heating steps.

[0096] The heating process includes a first step and a second step, which are performed sequentially. It can be understood that the first step is performed first and then the second step.

[0097] During the first step, the first switch and the corresponding second switch are closed, connecting the corresponding battery pack 10 to the switching circuit 20 and the first energy storage circuit 30, thereby enabling the battery pack 10 to enter the heating phase. After the battery pack 10 has completed heating, the second step is executed.

[0098] When performing the second step, the first switch and the corresponding second switch are disconnected so that the corresponding battery pack 10 is disconnected from the switch circuit 20 and the first energy storage circuit 30, thereby causing the battery pack 10 to exit the heating stage.

[0099] That is, when a certain battery pack 10 needs to be heated, the battery pack 10 will be connected to the switching circuit 20 and the first energy storage circuit 30 to be in the heating stage, and after the battery pack 10 has completed heating, the battery pack 10 will exit the heating stage. Thus, by sequentially connecting the battery packs 10, only one battery pack 10 is heated at a time.

[0100] By heating only one battery pack 10 at a time during the heating phase, the heating current is effectively utilized, thereby increasing the heating rate.

[0101] Referring to Figures 2, 6, and 7, Figure 6 is a third schematic diagram of the current path of the battery heating circuit in the first heating stage of some embodiments of this application; Figure 7 is a fourth schematic diagram of the current path of the battery heating circuit in the first heating stage of some embodiments of this application.

[0102] According to some embodiments of this application, a second energy storage circuit 50 is connected in parallel across the two ends of the battery. The first end of the second energy storage circuit 50 is connected to the positive terminal of each battery pack 10, and the second end of the second energy storage circuit 50 is connected to the negative terminal of each battery pack 10. The first heating stage further includes: repeatedly performing the steps of charging the second energy storage circuit 50 by the first battery cell 11 and charging the second battery cell 12 by the second energy storage circuit 50 N2 times via the switching circuit 20. Here, N2 is a positive integer greater than or equal to 1.

[0103] The second energy storage circuit 50 is a circuit that stores energy and releases it when needed. In some examples, external electrical energy is input to the second energy storage circuit 50 for storage, and the stored energy is released externally in the form of electrical energy when needed. The second energy storage circuit 50 includes an energy storage element, which can be a capacitor or an inductor. If the energy storage element of the first energy storage circuit 30 is an inductor, the energy storage element of the second energy storage circuit 50 is a capacitor.

[0104] The second energy storage circuit 50 is connected in parallel to both ends of the battery, that is, the first end of the second energy storage circuit 50 is connected to the first node C1, and the second end of the second energy storage circuit 50 is connected to the second node C2.

[0105] In the first heating stage, the connection state of each node is controlled by the control switch circuit 20, thereby forming different heating circuits.

[0106] As shown in Figure 6, when the second node C2 and the third node C3 are connected, the second battery unit 12 forms a second heating circuit with the first energy storage circuit 30, while the first battery unit 11 can also form a circuit with the second energy storage circuit 50. Therefore, the first battery unit 11 can charge the second energy storage circuit 50, and the second energy storage circuit 50 can store energy, thereby heating the first battery unit 11 through discharge. In Figure 6, the solid line with an arrow indicates the current path of the first battery unit 11 charging the second energy storage circuit 50.

[0107] As shown in Figure 7, when the first node C1 and the third node C3 are connected, the first battery unit 11 forms a first heating circuit with the first energy storage circuit 30, while the second battery unit 12 can also form a circuit with the second energy storage circuit 50. Therefore, the second energy storage circuit 50 can charge the second battery unit 12, thereby heating the second battery unit 12 through charging. In Figure 7, the solid line with an arrow indicates the current path of the second energy storage circuit 50 charging the second battery unit 12.

[0108] That is, during the first heating stage, the second energy storage circuit 50 enables the transfer of some electrical energy from the first battery cell 11 to the second battery cell 12.

[0109] The steps of repeatedly charging the second energy storage circuit 50 with the first battery cell 11 and charging the second battery cell 12 with the second energy storage circuit 50 N2 times refer to the energy input and output in the second energy storage circuit 50 each being performed N2 times. This process can be repeated multiple times until the temperature of the first battery cell 11 and the second battery cell 12 in all battery packs 10 is greater than a preset temperature. The number of times this process is performed is N2, and the value of N2 can be 1, 2, 3, or more than 3. The value of N2 can be the same as or different from the value of N1.

[0110] Repeating the process multiple times enables low-frequency heating of the battery, thereby improving the heating efficiency.

[0111] By setting up a second energy storage circuit 50, in the first heating stage, in addition to the first energy storage circuit 30, a portion of the electrical energy in the first battery cell 11 can be transferred to the second battery cell 12 through the second energy storage circuit 50, thereby improving the efficiency of energy transfer and further improving the heating efficiency of the battery.

[0112] Referring to Figures 6 and 7, according to some embodiments of this application, the first heating stage further includes: simultaneously charging the second energy storage circuit 50 by the first battery unit 11 and charging the second battery unit 12 by the first energy storage circuit 30 via the switching circuit 20; and / or simultaneously charging the second battery unit 12 by the second energy storage circuit 50 and charging the first energy storage circuit 30 by the first battery unit 11 via the switching circuit.

[0113] As shown in Figure 6, while the second battery unit 12 and the first energy storage circuit 30 form a second heating circuit, the first battery unit 11 can also form a circuit with the second energy storage circuit 50, charging the second energy storage circuit 50. Simultaneously, the first energy storage circuit 30 can also charge the second battery unit 12. That is, the charging of the second energy storage circuit 50 by the first battery unit 11 and the charging of the second battery unit 12 by the first energy storage circuit 30 are performed simultaneously. In other words, current always flows through the first battery unit 11 and the second battery unit 12, which helps maintain the stability of the current flowing through them. This improves the heating efficiency of the batteries and makes the performance of the first battery unit 11 and the second battery unit 12 more stable. In Figure 6, the solid line with arrows indicates the current path of the first battery unit 11 charging the second energy storage circuit 50, and the dashed line with arrows indicates the current path of the first energy storage circuit 30 charging the second battery unit 12.

[0114] As shown in Figure 7, while the first battery unit 11 and the first energy storage circuit 30 form a first heating circuit, the second battery unit 12 can also form a circuit with the second energy storage circuit 50, allowing the second energy storage circuit 50 to charge the second battery unit 12. Simultaneously, the first battery unit 11 can also charge the first energy storage circuit 30. That is, the charging of the second battery unit 12 by the second energy storage circuit 50 and the charging of the first energy storage circuit 30 by the first battery unit 11 are performed simultaneously. In other words, current always flows through the first battery unit 11 and the second battery unit 12, which helps maintain the stability of the current flowing through them. This improves the heating efficiency of the batteries and makes the performance of the first battery unit 11 and the second battery unit 12 more stable. In Figure 7, the solid line with arrows indicates the current path of the second energy storage circuit 50 charging the second battery unit 12, and the dashed line with arrows indicates the current path of the first battery unit 11 charging the first energy storage circuit 30.

[0115] With the cooperation of the first energy storage circuit 30 and the second energy storage circuit 50, during the switching process of the first heating circuit and the second heating circuit, current always flows through the first battery unit 11 and the second battery unit 12, which helps to maintain the stability of the current flowing through the first battery unit 11 and the second battery unit 12. While improving the heating efficiency of the battery, it also makes the performance of the first battery unit 11 and the second battery unit 12 more stable.

[0116] As shown in Figures 8 and 9, Figure 8 is one of the schematic diagrams of the current path of the battery heating circuit in the second heating stage according to some embodiments of this application; Figure 9 is another schematic diagram of the current path of the battery heating circuit in the second heating stage according to some embodiments of this application; wherein, in Figures 8 and 9, the direction of current flow is indicated by solid lines with arrows.

[0117] According to some embodiments of this application, the heating stage further includes a second heating stage. The second heating stage includes: repeatedly performing the steps of the second battery cell 12 charging the first energy storage circuit 30 and the first energy storage circuit 30 charging the first battery cell 11 N3 times via the switching circuit 20, where N3 is a positive integer greater than or equal to 1.

[0118] In the second heating stage, the connection state of each node is controlled by the control switch circuit 20, thereby forming different heating circuits.

[0119] As shown in Figure 8, when the second node C2 and the third node C3 are connected, the second battery unit 12 and the first energy storage circuit 30 form a second heating circuit. The second battery unit 12 charges the first energy storage circuit 30, and the first energy storage circuit 30 stores energy. Thus, the second battery unit 12 is heated by discharging.

[0120] As shown in Figure 9, when the first node C1 and the third node C3 are connected, the first battery unit 11 and the first energy storage circuit 30 form a first heating circuit. Since the first energy storage circuit 30 stores energy in the second heating circuit, it can charge the first battery unit 11 in the first heating circuit, thereby heating the first battery unit 11 through charging.

[0121] That is, in the second heating stage, the first energy storage circuit 30 realizes the transfer of part of the electrical energy in the second battery cell 12 to the first battery cell 11.

[0122] In the first heating stage, a portion of the electrical energy in the first battery cell 11 is transferred to the second battery cell 12, resulting in a decrease in the electrical energy of the first battery cell 11 and an increase in the electrical energy of the second battery cell 12. By adding a second heating stage based on the first heating stage, the increased electrical energy of the second battery cell 12 is transferred to the first battery cell 11 to a certain extent, thereby maintaining the energy balance between the first battery cell 11 and the second battery cell 12 while heating the battery.

[0123] The step of repeatedly charging the first energy storage circuit 30 with the second battery cell 12 and charging the first battery cell 11 with the first energy storage circuit 30 N3 times means that the energy input and output in the first energy storage circuit 30 are each performed N3 times. This can be performed multiple times until the temperature of the first battery cell 11 and the second battery cell 12 of all battery packs 10 is higher than the preset temperature. The number of times this is performed is N3. The value of N3 can be 1, 2, 3 or more. The value of N3 can be the same as or different from the value of N1. When N3 is close to N1, it indicates that the energy transferred in the first heating stage and the second heating stage is similar, and the energy of the first battery cell 11 and the second battery cell 12 is relatively balanced.

[0124] Repeating the process multiple times enables low-frequency heating of the battery, thereby improving the heating efficiency.

[0125] By adding a second heating stage on top of the first heating stage, the energy balance between the first battery cell 11 and the second battery cell 12 is maintained while the battery is heated by energy exchange between the first battery cell 11 and the second battery cell 12.

[0126] According to some embodiments of this application, the battery heating method further includes: controlling the battery to sequentially enter a first heating stage and a second heating stage.

[0127] Controlling the battery to sequentially enter the first heating stage and the second heating stage can be understood as either the first heating stage occurring after the second heating stage, or the first heating stage occurring before the second heating stage.

[0128] In some embodiments, each battery pack 10 is heated individually in sequence. During the heating process, the battery pack 10 is first controlled to be in a first heating stage, and then the battery pack 10 is controlled to be in a second heating stage, thereby completing the heating of the battery pack.

[0129] In some embodiments, the first heating phase and the second heating phase may be performed alternately multiple times.

[0130] By controlling the battery to be in the first heating stage and the second heating stage in sequence, the balance between the first battery cell 11 and the second battery cell 12 is maintained while the battery is heated.

[0131] As shown in Figures 10 and 11, Figure 10 is a third schematic diagram of the current path of the battery heating circuit in the second heating stage according to some embodiments of this application; Figure 11 is a fourth schematic diagram of the current path of the battery heating circuit in the second heating stage according to some embodiments of this application.

[0132] According to some embodiments of this application, a second energy storage circuit 50 is also connected in parallel across the two ends of the battery. The first end of the second energy storage circuit 50 is connected to the positive terminal of each battery pack 10, and the second energy storage circuit 50 is connected to the negative terminal of each battery pack 10. The second heating stage further includes: repeatedly performing the steps of charging the second energy storage circuit 50 by the second battery cell 12 and charging the first battery cell 11 by the second energy storage circuit 50 N4 times via the switching circuit 20, where N4 is a positive integer greater than or equal to 1.

[0133] As described in the above embodiments, the second energy storage circuit 50 is a circuit that stores energy and releases it when needed. In some examples, external electrical energy is input to the second energy storage circuit 50 for storage, and the stored energy is released externally in the form of electrical energy when needed. The second energy storage circuit 50 includes an energy storage element for energy storage, which can be a capacitor or an inductor. When the energy storage element of the first energy storage circuit 30 is an inductor, the energy storage element of the second energy storage circuit 50 is a capacitor.

[0134] The second energy storage circuit 50 is connected in parallel to both ends of the battery, that is, the first end of the second energy storage circuit 50 is connected to the first node C1, and the second end of the second energy storage circuit 50 is connected to the second node C2.

[0135] In the second heating stage, the connection state of each node is controlled by the control switch circuit 20, thereby forming different heating circuits.

[0136] As shown in Figure 10, when the first node C1 and the third node C3 are connected, the first battery unit 11 forms a first heating circuit with the first energy storage circuit 30, while the second battery unit 12 can also form a circuit with the second energy storage circuit 50. Therefore, the second battery unit 12 can charge the second energy storage circuit 50, thereby achieving heating of the second battery unit 12 through its discharge. In Figure 10, the solid line with an arrow indicates the current path of the second battery unit 12 charging the second energy storage circuit 50.

[0137] As shown in Figure 11, when the second node C2 and the third node C3 are connected, the second battery unit 12 forms a first heating circuit with the first energy storage circuit 30, while the first battery unit 11 can also form a circuit with the second energy storage circuit 50. Therefore, the second energy storage circuit 50 can charge the first battery unit 11. Thus, heating of the first battery unit 11 is achieved through charging. In Figure 11, the solid line with an arrow indicates the current path of the second energy storage circuit 50 charging the first battery unit 11.

[0138] That is, in the second heating stage, the second energy storage circuit 50 realizes the transfer of part of the electrical energy in the second battery cell 12 to the first battery cell 11.

[0139] The steps of repeatedly charging the second battery cell 12 for the second energy storage circuit 50 and charging the first battery cell 11 for the second energy storage circuit 50 N4 times refer to the energy input and output in the second energy storage circuit 50 each being performed N4 times. This process can be repeated multiple times until the temperature of the first battery cell 11 and the second battery cell 12 of all battery packs 10 is greater than a preset temperature. The number of times this is performed is N4, and the value of N4 can be 1, 2, 3, or more than 3. The value of N4 can be the same as or different from the value of N3.

[0140] Repeating the process multiple times enables low-frequency heating of the battery, thereby improving the heating efficiency.

[0141] By setting up a second energy storage circuit 50, in the second heating stage, in addition to the first energy storage circuit 30, a portion of the electrical energy in the second battery unit 12 can be transferred to the first battery unit 11 through the second energy storage circuit 50, thereby improving the efficiency of energy transfer and further improving the heating efficiency of the battery.

[0142] As shown in Figures 10 and 11, according to some embodiments of this application, the second heating stage further includes: simultaneously charging the second energy storage circuit 50 by the second battery unit 12 and charging the first energy storage circuit 30 by the first battery unit 11 by the first energy storage circuit 30 through the switching circuit 20; and / or, simultaneously charging the first battery unit 11 by the second energy storage circuit 50 and charging the first energy storage circuit 30 by the second battery unit 12 through the switching circuit 20.

[0143] As shown in Figure 10, while the first battery unit 11 and the first energy storage circuit 30 form a first heating circuit, the second battery unit 12 can also form a circuit with the second energy storage circuit 50, charging the second energy storage circuit 50. Simultaneously, the first energy storage circuit 30 can also charge the first battery unit 11. That is, the charging of the second energy storage circuit 50 by the second battery unit 12 and the charging of the first battery unit 11 by the first energy storage circuit 30 are performed simultaneously. In other words, current always flows through the first battery unit 11 and the second battery unit 12, which helps maintain the stability of the current flowing through them. This improves the heating efficiency of the batteries and makes the performance of the first battery unit 11 and the second battery unit 12 more stable. In Figure 10, the solid line with arrows indicates the current path of the second battery unit 12 charging the second energy storage circuit 50, and the dashed line with arrows indicates the current path of the first energy storage circuit 30 charging the first battery unit 11.

[0144] As shown in Figure 11, while the second battery unit 12 and the first energy storage circuit 30 form a first heating circuit, the first battery unit 11 can also form a circuit with the second energy storage circuit 50. The second energy storage circuit 50 charges the first battery unit 11, and simultaneously, the second battery unit 12 can also charge the first energy storage circuit 30. That is, the second energy storage circuit 50 charges the first battery unit 11, and the second battery unit 12 charges the first energy storage circuit 30 simultaneously. In other words, current always flows through the first battery unit 11 and the second battery unit 12, which helps maintain the stability of the current flowing through them. This improves the heating efficiency of the batteries and makes the performance of the first battery unit 11 and the second battery unit 12 more stable. In Figure 11, the solid line with an arrow indicates the current path of the second energy storage circuit 50 charging the first battery unit 11, and the dashed line with an arrow indicates the current path of the second battery unit 12 charging the first energy storage circuit 30.

[0145] With the cooperation of the first energy storage circuit 30 and the second energy storage circuit 50, during the switching process of the first heating circuit and the second heating circuit, current always flows through the first battery unit 11 and the second battery unit 12, which helps to maintain the stability of the current flowing through the first battery unit 11 and the second battery unit 12. While improving the heating efficiency of the battery, it also makes the performance of the first battery unit 11 and the second battery unit 12 more stable.

[0146] Referring to Figures 2 to 4, according to some embodiments of this application, the switching circuit 20 includes bridge arms. The bridge arms include an upper bridge arm and a lower bridge arm connected in series. The upper bridge arm is connected to the positive terminal of each battery pack 10, and the lower bridge arm is connected to the negative terminal of each battery pack 10. A first terminal of the first energy storage circuit 30 is connected between the upper and lower bridge arms. In the battery heating method of the above embodiments, the steps of repeatedly charging the first battery cell 11 for the first energy storage circuit 30 and charging the second battery cell 12 for N1 times via the switching circuit 20 include: sequentially and alternately performing a third step and a fourth step. The third step includes controlling the upper bridge arm to be on and the lower bridge arm to be off. The fourth step includes controlling the lower bridge arm to be on and the upper bridge arm to be off.

[0147] The first node C1 corresponds to the side of the upper bridge arm away from the lower bridge arm, the second node C2 corresponds to the side of the lower bridge arm away from the upper bridge arm, and the third node C3 corresponds to the node between the upper and lower bridge arms. The on / off state of the upper bridge arm is controlled by the switching element of the upper bridge arm, and the on / off state of the lower bridge arm is controlled by the switching element of the lower bridge arm.

[0148] In some embodiments, the switching element of the upper bridge arm can be an upper bridge arm switch V1, and the switching element of the lower bridge arm can be a lower bridge arm switch V2. By turning the upper bridge arm switch V1 on / off, the upper bridge arm can be turned on / off, and by turning the lower bridge arm switch V2 on / off, the lower bridge arm can be turned on / off.

[0149] The types of upper bridge arm switching transistor V1 and lower bridge arm switching transistor V2 include, but are not limited to, MOS transistors (Metal-Oxide-Semiconductor Field-Effect Transistors), IGBT transistors (Insulated-Gate Bipolar Transistors), or relays, etc., which are components capable of controlling the on and off of the circuit.

[0150] In some embodiments, the upper bridge arm switch V1 is equipped with a first freewheeling diode D1, and the lower bridge arm switch V2 is equipped with a second freewheeling diode D2. During the transition from the third to the fourth step, i.e., when the upper bridge arm switches from on to off, current can flow through the first freewheeling diode D1, ensuring a continuous current flow through the inductor during the transition. Similarly, during the transition from the fourth to the third step, current can flow through the second freewheeling diode D2. Thus, throughout the entire first heating stage, current flows through the inductor, resulting in a smaller rate of change of current through the inductor and a lower frequency of current flowing through it. When there are multiple inductors, and these inductors are three-phase inductors in the motor, this can mitigate the problem of high-frequency whistling caused by excessive current flowing through the motor, maintaining more stable motor performance and improving battery heating efficiency.

[0151] In some embodiments, the number of bridge arms can be multiple, and the multiple bridge arms are connected in parallel. The first energy storage circuit 30 includes multiple first inductors L1 connected in parallel, and the multiple first inductors L1 are connected to the multiple bridge arms one by one.

[0152] As shown in Figure 3, when performing the third step, a first heating circuit is formed. The current flows out from the positive terminal of the first battery cell 11 and passes through each bridge arm and the corresponding first inductor L1, so that the first battery cell 11 charges each first inductor L1 of the first energy storage circuit 30.

[0153] As shown in Figure 4, when the fourth step is performed, a second heating circuit is formed so that each of the first inductors L1 of the first energy storage circuit 30 releases energy to charge the second battery cell 12.

[0154] In some embodiments, the first energy storage circuit 30 further includes a second inductor L2, wherein a plurality of first inductors L1 are connected in parallel and then connected in series with the second inductor L2. In the third step, the first battery unit 11 charges the plurality of first inductors L1 and the second inductor L2. In the fourth step, the plurality of first inductors L1 and the second inductor L2 charge the second battery unit 12.

[0155] By alternately executing the third and fourth steps, the first heating circuit and the second heating circuit are switched so that the battery is in the first heating stage.

[0156] In some embodiments, the interval between the alternating execution of the third and fourth steps is a preset duration. For example, after executing the third step, the fourth step is executed after a preset duration, which is equivalent to the first heating circuit maintaining the preset duration, allowing the first battery unit 11 to fully charge the first energy storage circuit 30 for the preset duration. Similarly, after executing the fourth step, the third step is executed after a preset duration, which is equivalent to the second heating circuit maintaining the preset duration, allowing the first energy storage circuit 30 to fully charge the second battery unit 12 for the preset duration. The preset duration can be appropriately increased to maintain the charging and discharging states, thereby improving heating efficiency. The preset duration can be 1 second, 1.1 seconds, 1.2 seconds, 1.3 seconds, 1.4 seconds, or 1.5 seconds, etc.

[0157] By controlling the alternating conduction of the upper and lower bridge arms, energy transfer from the first battery cell 11 to the second battery cell 12 can be achieved.

[0158] As shown in Figures 8 and 9, according to some embodiments of this application, the heating stage further includes a second heating stage, which includes: repeatedly performing the steps of the second battery cell 12 charging the first energy storage circuit 30 and the first energy storage circuit 30 charging the first battery cell 11 N3 times via a switching circuit, where N3 is a positive integer greater than or equal to 1. Repeating the steps of the second battery cell 12 charging the first energy storage circuit 30 and the first energy storage circuit 30 charging the first battery cell 11 N3 times via a switching circuit 20 includes: sequentially and alternately performing a fourth step and a third step.

[0159] As shown in Figure 8, during the fourth step, a second heating circuit is formed so that the second battery cell 12 charges the first energy storage circuit 30.

[0160] As shown in Figure 9, when the third step is performed, a first heating circuit is formed so that the first energy storage circuit 30 charges the first battery cell 11.

[0161] By alternately executing the fourth and third steps, the second heating circuit and the first heating circuit are switched so that the battery is in the second heating stage.

[0162] By controlling the alternating conduction of the upper and lower bridge arms, energy transfer from the second battery cell 12 to the first battery cell 11 can be achieved.

[0163] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the battery heating method further includes: after the battery is in the heating stage to heat the battery, controlling all equalization branches 40 to be in a conducting state.

[0164] During the process of heating each battery pack 10 in sequence, energy transfer is achieved between the first battery unit 11 and the second battery unit 12. After heating is completed, there may be an imbalance of electrical energy between the first battery unit 11 and the second battery unit 12 of each battery pack 10.

[0165] The balancing branch 40 is a circuit used to balance the voltages of each first battery cell 11 and each second battery cell 12 so that the voltages of each first battery cell 11 and each second battery cell 12 can be kept approximately the same.

[0166] When the battery is in the heating stage, all equalization branches 40 are disconnected. After the battery has finished heating, all equalization branches 40 are turned on. At this time, all first battery cells 11 are connected in parallel and all second battery cells 12 are connected in parallel, thereby balancing each first battery cell 11 and each second battery cell 12.

[0167] In some embodiments, when the BMS detects that the balancing current is less than a first threshold and the voltage difference is less than a second threshold, it disconnects all balancing branches 40 to enable normal battery use.

[0168] By setting up the equalization branch 40, the first battery cell 11 and the second battery cell 12 are equalized after the battery heating is completed.

[0169] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, a balancing branch 40 is provided between each pair of adjacent battery packs 10. In each pair of adjacent battery packs 10, the first end of the balancing branch 40 is connected to the midpoint between the first battery cell 11 and the second battery cell 12 of one battery pack, and the second end of the balancing branch 40 is connected to the midpoint between the first battery cell 11 and the second battery cell 12 of the other battery pack. The balancing branch 40 includes a switch K11 connected in series and a resistive load R. Controlling the battery to be in the heating stage to heat the battery includes controlling all balancing branches 40 to be in the open state, which includes controlling all switches K11 to be in the open state. After the battery is in the heating stage to heat the battery, controlling all balancing branches 40 to be in the conducting state includes controlling all switches K11 to be in the closed state.

[0170] If there is a balancing branch 40 between each two adjacent battery packs 10, then the number of balancing branches 40 is equal to the number of battery packs minus one.

[0171] The resistive load R is used to alleviate the problem of large current caused by large voltage differences in battery cells before equalization.

[0172] In some embodiments, the resistive load R can be a heating resistive element, specifically a PTC, so that the heat generated by heating the resistive element during the equilibration process can be utilized.

[0173] By setting switch K11 and resistive load R, the on / off switching of branch 40 can be balanced, and the problem of large current caused by large voltage difference can also be alleviated.

[0174] As shown in Figures 2 to 4 and Figures 6 to 11, embodiments of this application provide a battery heating circuit. The battery includes multiple battery packs 10 connected in parallel, each battery pack 10 including a first battery cell 11 and a second battery cell 12 connected in series. The battery heating circuit includes a switching circuit 20 and a first energy storage circuit 30. A first terminal of the switching circuit 20 is connected to the positive terminal of each battery pack 10, and a second terminal of the switching circuit 20 is connected to the negative terminal of each battery pack 10. A first terminal of the first energy storage circuit 30 is connected to the switching circuit 20, and a second terminal of the first energy storage circuit 30 is connected to the midpoint between the first battery cell 11 and the second battery cell 12 of each battery pack 10. The switching circuit 20 is configured to connect the first battery cell 11 to the first energy storage circuit 30 to form a first heating circuit, and to connect the second battery cell 12 to the first energy storage circuit 30 to form a second heating circuit.

[0175] In some embodiments, the controller can control the battery to be in a first heating stage and a second heating stage in sequence. In the first heating stage, energy transfer is realized from the first battery cell 11 to the second battery cell 12, and in the second heating stage, energy transfer is realized from the second battery cell 12 to the first battery cell 11, thereby completing the heating of the battery.

[0176] The specific methods of controller control can be found in the descriptions of the above embodiments, and will not be repeated hereafter.

[0177] By controlling the switching circuit 20, each of the parallel battery packs 10 can be heated by charging and discharging the battery packs 10.

[0178] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the first terminal of the switching circuit 20 is connected to the first connection point P1, and the positive terminal of each battery pack 10 is connected to the first connection point P1 through a first switch (K4, K5, K6). The second terminal of the first energy storage circuit 30 is connected to the second connection point P2, and the midpoint between the first battery cell 11 and the second battery cell 12 of each battery pack 10 is connected to the second connection point P2 through a second switch (K9, K8, K7).

[0179] Under the control of the first switch and the corresponding second switch, during the heating phase, each battery pack 10 can be heated sequentially in a certain order. That is, during the heating phase, only one battery pack 10 is heated at a time, meaning only one battery pack 10 is connected to the switching circuit 20 and the first energy storage circuit 30. While one battery pack 10 is in the heating phase, the remaining battery packs 10 are in the non-heating phase, until all battery packs 10 have been heated. Since only one battery pack 10 is heated at a time, the heating current flows only in one battery pack 10 and is not distributed to other battery packs 10, thus increasing the heating rate.

[0180] The specific control scheme can be found in the description of the above embodiments, and will not be repeated hereafter.

[0181] By controlling the first switch (K4, K5, K6) and the second switch (K9, K8, K7), only one battery pack 10 can be heated at a time during the heating stage, thereby effectively utilizing the heating current and increasing the heating rate.

[0182] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the switching circuit 20 includes at least one switching branch 21, with both ends of the switching branch 21 connected to a first connection point P1 and the negative terminal of each battery pack 10, respectively. The switching branch 21 includes a first switching element and a second switching element connected in series, with the midpoint between the first switching element and the second switching element connected to a first terminal of the first energy storage circuit 30.

[0183] The first switching element is located between the first node C1 and the third node C3, and is used to control the on / off state between the first node C1 and the third node C3. The second switching element is located between the second node C2 and the third node C3, and is used to control the on / off state between the second node C2 and the third node C3.

[0184] With the cooperation of the first and second switching elements, different heating circuits can be formed and switching can be performed between different heating circuits. For specific details, please refer to the relevant descriptions in the above embodiments, which will not be repeated below.

[0185] Different heating circuits can be formed and switched between different heating circuits by means of the first and second switching elements.

[0186] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, there are multiple switch branches 21, and the multiple switch branches 21 are connected in parallel. The first energy storage circuit 30 includes multiple first energy storage elements connected in parallel. The multiple first energy storage elements are connected one-to-one to the midpoint between the first switch elements and the second switch elements of the multiple switch branches 21.

[0187] The first end of each first energy storage element is connected to the midpoint between the first and second switching elements of the corresponding switching branch. Multiple first energy storage elements can form multiple first heating circuits and multiple second heating circuits.

[0188] In some embodiments, the number of switch branches 21 can be two, three or more. The number of switch branches 21 can be adjusted according to different heating requirements to achieve a better heating effect.

[0189] The first energy storage element may include, but is not limited to, inductors or capacitors and other elements capable of storing energy.

[0190] By setting up multiple first energy storage elements and multiple switch branches 21 in a one-to-one correspondence, multiple first heating circuits or multiple second heating circuits can be formed, thereby improving the heating efficiency of the battery.

[0191] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the first energy storage circuit 30 further includes a second energy storage element, which is connected in series with a plurality of first energy storage elements that are connected in parallel.

[0192] The second energy storage element and multiple first energy storage elements together constitute the first energy storage circuit 30, thereby enabling the storage and release of electrical energy.

[0193] By adding a second energy storage element, the heating efficiency and reliability were improved.

[0194] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the first energy storage element and the second energy storage element are inductors.

[0195] An inductor is an electronic component that can convert electrical energy into magnetic energy and store it, and can release the magnetic energy through a circuit.

[0196] In some embodiments, as shown in FIG2, three first inductors L1 are connected in parallel and then connected in series with a second inductor L2.

[0197] By configuring the first and second energy storage elements as inductors, energy storage and release are achieved through inductors.

[0198] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the first energy storage circuit 30 includes three first inductors L1 connected in parallel, which are multiplexed from the three-phase inductors in the motor.

[0199] When heating the vehicle's battery, the vehicle's existing motor can be used to heat the battery, eliminating the need for an additional heating inductor and reducing costs.

[0200] By reusing the three-phase inductors in the motor to form the first energy storage circuit 30, the overall cost is reduced.

[0201] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the switch branch 21 is a bridge arm, which includes an upper bridge arm and a lower bridge arm connected in series. The upper bridge arm is connected to the positive terminal of each battery pack 10, and the lower bridge arm is connected to the negative terminal of each battery pack 10. The first terminal of the first energy storage circuit 30 is connected between the upper bridge arm and the lower bridge arm. The switching element of the upper bridge arm serves as the first switching element, and the switching element of the lower bridge arm serves as the second switching element.

[0202] Under the control of the upper and lower bridge arms, energy transfer between the first battery cell 11 and the second battery cell 12 can be realized. For details, please refer to the relevant description of the above embodiments, which will not be repeated below.

[0203] By configuring the switch branch 21 as a bridge arm, the structure of the bridge arm is simple and easy to control, which simplifies the circuit and improves the reliability of battery heating control.

[0204] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the battery heating circuit further includes an equalization branch 40. An equalization branch 40 is provided between each of two adjacent battery packs. In each of the two adjacent battery packs, the first end of the equalization branch 40 is connected to the midpoint between the first battery cell 11 and the second battery cell 12 of one of the packs, and the second end of the equalization branch 40 is connected to the midpoint between the first battery cell 11 and the second battery cell 12 of the other pack.

[0205] The equalization branch 40 is configured to disconnect when the battery is heating up and turn on after the battery has finished heating up. For specific control methods, please refer to the relevant descriptions in the above embodiments; they will not be repeated below.

[0206] In some embodiments, the balancing branch 40 includes a switch K11 connected in series and a resistive load R. The resistive load R is used to alleviate the problem of large current caused by the large voltage difference between battery cells before balancing. The resistive load R can be a heating resistive element, specifically a PTC, so that the heat generated by heating the resistive element during the balancing process can be utilized.

[0207] By setting up the equalization branch 40, the first battery cell 11 and the second battery cell 12 are equalized after the battery heating is completed.

[0208] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the battery heating circuit further includes a second energy storage circuit 50. The first terminal of the second energy storage circuit 50 is connected to the positive terminal of each battery pack 10, and the second terminal of the second energy storage circuit 50 is connected to the negative terminal of each battery pack 10.

[0209] Energy transfer can be achieved between the first battery unit 11 and the second energy storage circuit 50, and between the second battery unit 12 and the second energy storage circuit 50, thereby performing the first heating stage and the second heating stage respectively. Specific implementation methods can be found in the descriptions of the above embodiments, and will not be repeated below.

[0210] By adding a second energy storage circuit 50, the efficiency of energy transfer is improved, thereby further improving the heating efficiency of the battery.

[0211] As shown in Figures 2 to 4 and Figures 6 to 11, according to some embodiments of this application, the first energy storage circuit 30 includes at least one inductor, and the second energy storage circuit 50 includes a capacitor.

[0212] Both inductors and capacitors can be used as energy storage elements for energy storage.

[0213] Through the cooperation of inductors and capacitors, energy exchange is achieved between the first battery cell 11 and the second battery cell 12.

[0214] An embodiment of the third aspect of this application provides a battery device including a battery and a battery heating circuit as described in any of the above embodiments. The battery heating circuit is connected to the battery and is used to heat the battery.

[0215] The battery device has the beneficial effects of the battery heating circuit provided in the embodiments of this application. For details, please refer to the specific description of the battery heating circuit in the above embodiments, which will not be repeated here.

[0216] According to some embodiments of this application, the battery includes multiple battery packs connected in parallel, each battery pack including a first battery cell and a second battery cell connected in series.

[0217] An embodiment of the fourth aspect of this application provides an electrical device including a battery device as described in the above embodiments, the battery device being used to provide electrical energy.

[0218] The electrical equipment has the beneficial effects of the battery device provided in the embodiments of this application. For details, please refer to the above description of the battery device, which will not be repeated here.

[0219] An embodiment of the fifth aspect of this application provides an energy storage device, including a battery device as described in the above embodiments.

[0220] The energy storage device has the beneficial effects of the battery device provided in the embodiments of this application. For details, please refer to the above description of the battery device, which will not be repeated here.

[0221] The embodiments of this application will be described in further detail below with reference to Figures 2 to 4 and Figures 6 to 11.

[0222] The battery includes three battery packs 10, each of which includes a first battery cell 11 and a second battery cell 12 connected in series.

[0223] The battery heating circuit includes a switching circuit 20, a first energy storage circuit 30, and an equalization branch 40.

[0224] The first terminal of the switching circuit 20 is connected to the positive terminal of each battery pack 10, and the second terminal of the switching circuit 20 is connected to the negative terminal of each battery pack 10. The switching circuit 20 includes three bridge arms, each of which includes an upper bridge arm and a lower bridge arm connected in series.

[0225] The first energy storage circuit 30 includes three first inductors L1 connected in parallel, and a second inductor L2 connected in series with the three first inductors L1. The first terminal of the first energy storage circuit 30 is connected to the midpoint between the upper bridge arm and the lower bridge arm, and the second terminal of the first energy storage circuit 30 is connected to the midpoint between the first battery cell 11 and the second battery cell 12 of each battery pack 10.

[0226] Two equalization branches 40 are provided. In two adjacent battery packs 110, the first end of the equalization branch 40 is connected to the midpoint of the first battery cell 11 and the second battery cell 12 of one of them, and the second end of the equalization branch 40 is connected to the midpoint of the first battery cell 11 and the second battery cell 12 of the other. The equalization branch 40 includes a switch K11 and a resistive load R.

[0227] When battery heating is required, the heating process involves heating the first battery pack 10, the second battery pack 10, and the third battery pack 10 sequentially and individually. During the heating process, both equalization branches are disconnected.

[0228] During the heating process of each battery pack 10, a first heating stage is first performed to transfer energy from the first battery cell 11 to the second battery cell 12. Then, a second heating stage is performed to transfer energy from the second battery cell 12 to the first battery cell 11.

[0229] After all the battery packs 10 have been heated, the two equalization branches 40 are turned on to equalize the three first battery cells 11 and the three second battery cells 12.

[0230] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery heating method, the battery comprising a plurality of battery packs (10) connected in parallel, each battery pack (10) comprising a first battery unit (11) and a second battery unit (12) connected in series, a first terminal of a switching circuit (20) connected to the positive terminal of each battery pack (10), and a second terminal of the switching circuit (20) connected to the negative terminal of each battery pack (10); a first terminal of a first energy storage circuit (30) connected to the switching circuit (20), and a second terminal of the first energy storage circuit (30) connected to the midpoint between the first battery unit (11) and the second battery unit (12) of each battery pack (10); the battery heating method comprising: Obtain the temperature of the battery; In response to the battery temperature being lower than a preset temperature, the switching circuit controls the battery to enter a heating phase to heat the battery. This heating phase includes a first heating phase. The first heating stage includes: repeatedly performing the steps of the first battery cell (11) charging the first energy storage circuit (30) and the first energy storage circuit (30) charging the second battery cell (12) N1 times through the switching circuit, where N1 is a positive integer greater than or equal to 1.

2. The battery heating method according to claim 1, wherein, The first end of the switching circuit (20) is connected to the first connection point (P1), and the positive terminal of each battery pack (10) is connected to the first connection point (P1) through a first switch (K4; K5; K6); the second end of the first energy storage circuit (30) is connected to the second connection point (P2), and the midpoint between the first battery cell (11) and the second battery cell (12) of each battery pack (10) is connected to the second connection point (P2) through a second switch (K9; K8; K7); controlling the battery to be in the heating stage to heat the battery includes: The first switch (K4; K5; K6) and the second switch (K9; K8; K7) control multiple battery packs (10) to independently enter the heating phase to heat the batteries.

3. The battery heating method according to claim 2, wherein, The step of controlling multiple battery packs (10) to independently enter the heating phase to heat the battery via the first switch (K4; K5; K6) and the second switch (K9; K8; K7) includes: A heating step is performed sequentially on each of the battery packs (10), the heating step including a first step and a second step performed sequentially; The first step includes controlling the first switch (K4; K5; K6) and the corresponding second switch (K9; K8; K7) to be in a closed state, and the second step includes controlling the first switch (K4; K5; K6) and the corresponding second switch (K9; K8; K7) to be in an open state.

4. The battery heating method according to any one of claims 1-3, wherein, A second energy storage circuit (50) is connected in parallel to both ends of the battery. The first end of the second energy storage circuit (50) is connected to the positive terminal of each battery pack (10), and the second end of the second energy storage circuit (50) is connected to the negative terminal of each battery pack (10). The first heating stage further includes: repeatedly performing the steps of the first battery cell (11) charging the second energy storage circuit (50) and the second energy storage circuit (50) charging the second battery cell (12) N2 times through the switching circuit, where N2 is a positive integer greater than or equal to 1.

5. The battery heating method according to claim 4, wherein, The first heating stage also includes: Through the switching circuit (20), the first battery cell (11) charges the second energy storage circuit (50) and the first energy storage circuit (30) charges the second battery cell (12) simultaneously; and / or The switching circuit (20) simultaneously enables the second energy storage circuit (50) to charge the second battery cell (12) and the first battery cell (11) to charge the first energy storage circuit (30).

6. The battery heating method according to any one of claims 1-5, wherein, The heating stage also includes a second heating stage; The second heating stage includes: repeatedly performing the steps of the second battery cell (12) charging the first energy storage circuit (30) and the first energy storage circuit (30) charging the first battery cell (11) N3 times through the switching circuit (20), where N3 is a positive integer greater than or equal to 1.

7. The battery heating method according to claim 6, wherein, The control of the battery to be in a heating phase includes controlling the battery to be in a first heating phase and a second heating phase in sequence.

8. The battery heating method according to claim 6 or 7, wherein, A second energy storage circuit (50) is connected in parallel to both ends of the battery. The first end of the second energy storage circuit (50) is connected to the positive terminal of each battery pack (10), and the second end of the second energy storage circuit (50) is connected to the negative terminal of each battery pack (10). The second heating stage further includes: repeatedly performing the steps of the second battery cell (12) charging the second energy storage circuit (50) and the second energy storage circuit (50) charging the first battery cell (11) N4 times through the switching circuit (20), where N4 is a positive integer greater than or equal to 1.

9. The battery heating method according to claim 8, wherein, The second heating stage also includes: Through the switching circuit (20), the second battery cell (12) simultaneously charges the second energy storage circuit (50) and the first energy storage circuit (30) simultaneously charges the first battery cell (11); and / or The switching circuit (20) simultaneously enables the second energy storage circuit (50) to charge the first battery cell (11) and the second battery cell (12) to charge the first energy storage circuit (30).

10. The battery heating method according to any one of claims 1-9, wherein, The switching circuit includes: a bridge arm comprising an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm being connected to the positive terminal of each of the battery packs (10), and the lower bridge arm being connected to the negative terminal of each of the battery packs (10); a first terminal of the first energy storage circuit is connected between the upper bridge arm and the lower bridge arm; wherein, The step of repeatedly charging the first battery cell (11) for the first energy storage circuit (30) and charging the second battery cell (12) for the first energy storage circuit (30) N1 times through the switching circuit (20) includes: sequentially and alternately performing the third step and the fourth step; The third step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off; The fourth step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off.

11. The battery heating method according to claim 10, wherein, The heating stage also includes a second heating stage; The second heating stage includes: repeatedly performing the steps of the second battery cell (12) charging the first energy storage circuit (30) and the first energy storage circuit (30) charging the first battery cell (11) N3 times through the switching circuit (20), where N3 is a positive integer greater than or equal to 1; The step of repeatedly charging the first energy storage circuit (30) by the second battery unit (12) and charging the first battery unit (11) by the first energy storage circuit (30) through the switching circuit (20) N3 times includes: sequentially and alternately performing the fourth step and the third step.

12. The battery heating method according to any one of claims 1-11, wherein, The battery heating method further includes: after the battery is in the heating stage to heat the battery, controlling all equalization branches (40) to be in the conducting state.

13. The battery heating method according to claim 12, wherein, The equalization branch (40) is provided between each of the two adjacent battery packs (10); in the two adjacent battery packs (10), the first end of the equalization branch (40) is connected to the midpoint between the first battery cell (11) and the second battery cell (12) of one of them, and the second end of the equalization branch (40) is connected to the midpoint between the first battery cell (11) and the second battery cell (12) of the other; the equalization branch includes a switch (K11) and a resistive load (R) connected in series; The control of the battery to be in the heating stage to heat the battery includes: controlling all the switches (K11) to be in the off state; After the battery is in the heating stage to heat the battery, controlling all the equalization branches (40) to be in the conducting state includes controlling all the switches (K11) to be in the closed state.

14. A battery heating circuit, wherein, The battery comprises multiple battery packs connected in parallel, each battery pack (10) including a first battery cell (11) and a second battery cell (12) connected in series; the battery heating circuit includes: A switching circuit (20) is provided, wherein the first end of the switching circuit (20) is connected to the positive terminal of each battery pack (10), and the second end of the switching circuit (20) is connected to the negative terminal of each battery pack (10). A first energy storage circuit (30) is connected at its first end to the switching circuit (20), and at its second end to the midpoint between the first battery cell (11) and the second battery cell (12) of each battery pack (10). The switching circuit is configured to connect the first battery cell (11) to the first energy storage circuit (30) to form a first heating circuit, and to connect the second battery cell (12) to the first energy storage circuit (30) to form a second heating circuit.

15. The battery heating circuit according to claim 14, wherein, The first end of the switching circuit (20) is connected to the first connection point (P1), and the positive terminal of each battery pack (10) is connected to the first connection point (P1) through a first switch (K4; K5; K6); The second end of the first energy storage circuit (30) is connected to the second connection point (P2), and the midpoint between the first battery cell (11) and the second battery cell (12) of each battery pack (10) is connected to the second connection point (P2) through a second switch (K9; K8; K7).

16. The battery heating circuit according to claim 15, wherein, The switching circuit (20) includes at least one switching branch (21), and the two ends of the switching branch (21) are respectively connected to the first connection point (P1) and the negative terminal of each battery pack (10); The switch branch (21) includes a first switch element and a second switch element connected in series, and the midpoint between the first switch element and the second switch element is connected to the first end of the first energy storage circuit (30).

17. The battery heating circuit according to claim 16, wherein, The number of the switch branches (21) is multiple, and the multiple switch branches (21) are connected in parallel. The first energy storage circuit (30) includes multiple first energy storage elements connected in parallel. The multiple first energy storage elements are connected one-to-one to the midpoint between the first switch element and the second switch element of the multiple switch branches (21).

18. The battery heating circuit according to claim 17, wherein, The first energy storage circuit (30) further includes a second energy storage element, which is connected in series with a plurality of the first energy storage elements connected in parallel.

19. The battery heating circuit according to claim 18, wherein, The first energy storage element and the second energy storage element are inductors.

20. The battery heating circuit according to any one of claims 17-19, wherein, The first energy storage circuit (30) includes three first inductors (L1) connected in parallel, which are multiplexed from the three-phase inductors in the motor.

21. The battery heating circuit according to claim 16, wherein, The switch branch (21) is a bridge arm, which includes an upper bridge arm and a lower bridge arm connected in series. The switch element of the upper bridge arm serves as the first switch element, and the switch element of the lower bridge arm serves as the second switch element.

22. The battery heating circuit according to any one of claims 14-21, wherein, The battery heating circuit further includes: a balancing branch (40); The equalization branch is provided between each of the two adjacent battery packs; in the two adjacent battery packs, one end of the equalization branch is connected to the midpoint between the first battery cell (11) and the second battery cell (12) of one of them, and the other end of the equalization branch (40) is connected to the midpoint between the first battery cell (11) and the second battery cell (12) of the other.

23. The battery heating circuit according to any one of claims 14-21, wherein, The battery heating circuit also includes: The second energy storage circuit (50) has its first end connected to the positive terminal of each of the battery packs (10) and its second end connected to the negative terminal of each of the battery packs (10).

24. The battery heating circuit according to claim 23, wherein, The first energy storage circuit (30) includes at least one inductor, and the second energy storage circuit (50) includes a capacitor.

25. A battery device, wherein, It includes a battery and a battery heating circuit as described in any one of claims 14-24; the battery heating circuit is connected to the battery and is used to heat the battery.

26. The battery device according to claim 25, wherein, The battery comprises multiple battery packs connected in parallel, and each battery pack includes a first battery cell and a second battery cell connected in series.

27. An electrical appliance, wherein, The electrical device includes a battery device as described in claim 25 or 26, the battery device being used to provide electrical energy.

28. An energy storage device, wherein, The energy storage device includes the battery device as described in claim 25 or 26.

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