Battery heating method, circuit, battery system and electrical apparatus

Abstract

The present application belongs to the technical field of batteries. Provided are a battery heating method, a circuit, a battery system and an electrical apparatus. A battery comprises a first battery pack and a second battery pack connected in series, a positive electrode of the battery being connected to a first end of a switch circuit, and a negative electrode of the battery being connected to a second end of the switch circuit; the switch circuit is further connected to a first end of a first energy storage circuit, and a second end of the first energy storage circuit is connected to the midpoint of the first battery pack and the second battery pack. The battery heating method comprises: acquiring the temperature of the battery; and in response to the battery temperature being less than a preset temperature threshold, controlling, by means of the switch circuit, the battery to be in a first heating stage so as to heat the battery, the first heating stage comprising: by means of the switch circuit, repeatedly executing the steps of charging the first energy storage circuit by means of the first battery pack and charging the second battery pack by means of the first energy storage circuit for N1 times, where N1 is a positive integer greater than 1. The battery heating method of the present application can improve the self-heating efficiency for batteries.

Description

Battery heating methods, circuits, battery systems and electrical devices

[0001] Cross-referencing

[0002] This application incorporates Chinese Patent Application No. 202411729893.3, filed on November 28, 2024, entitled “Battery Heating Method, Circuit, Battery System and Electrical 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 system and electrical 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] To address the issue of low battery charging efficiency in low-temperature environments, the battery can be preheated, and then charged once the battery temperature reaches the required level. However, current methods typically employ external heating devices, resulting in relatively low heating efficiency. Summary of the Invention

[0006] This application aims to at least address one of the technical problems existing in the background art. Therefore, one objective of this application is to provide a battery heating method to solve the aforementioned problems existing in the related art.

[0007] An embodiment of the first aspect of this application provides a battery heating method. The battery includes a first battery pack and a second battery pack connected in series. The positive terminal of the battery is connected to a first terminal of a switching circuit, and the negative terminal of the battery is connected to a second terminal of the switching circuit. The switching circuit is also connected to a first terminal of a first energy storage circuit. The second terminal of the first energy storage circuit is connected to the midpoint between the first battery pack and the second battery pack. The battery heating method includes: acquiring the temperature of the battery; and, in response to the battery temperature being lower than a preset temperature threshold, controlling the battery to be in a first heating stage to heat the battery via the switching circuit. The first heating stage includes: repeatedly performing the steps of the first battery pack charging the first energy storage circuit and the first energy storage circuit charging the second battery pack N1 times via the switching circuit, where N1 is a positive integer greater than 1.

[0008] In the technical solution of this application embodiment, during the first heating stage, energy from the first battery pack is transferred to the second battery pack, achieving self-heating of both the first and second battery packs. This eliminates the need for external heating equipment, reducing costs. Furthermore, repeating the steps of charging the first energy storage circuit from the first battery pack to the first energy storage circuit and vice versa N1 times during the first heating stage significantly improves the efficiency of energy transfer from the first battery pack to the second battery pack compared to performing these steps only once during the first heating stage. This, in turn, enhances the heating efficiency of the battery heating achieved through the first energy storage circuit.

[0009] In some embodiments, the method further includes: in response to the battery temperature being lower than a preset temperature threshold, controlling the battery to enter a second heating stage via a switching circuit to heat the battery. The second heating stage includes: repeatedly performing the steps of the second battery pack charging the first energy storage circuit and the first energy storage circuit charging the first battery pack N2 times via the switching circuit, where N2 is a positive integer greater than 1. In the second heating stage, energy is transferred from the second battery pack to the first battery pack, achieving heating of both the first and second battery packs. This allows energy exchange between the first and second battery packs, thereby maintaining energy balance between them while heating them.

[0010] 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 the battery, and the second end is connected to the negative terminal. The first heating stage further includes: repeatedly performing the steps of charging the second energy storage circuit from the first battery pack and charging the second battery pack from the second energy storage circuit N3 times via a switching circuit, where N3 is a positive integer greater than 1. The second energy storage circuit can also realize energy transfer from the first battery pack to the second battery pack, further improving the battery's heating efficiency.

[0011] In some embodiments, the first heating stage further includes: simultaneously charging the first energy storage circuit with the first battery pack and charging the second energy storage circuit with the second battery pack via a switching circuit; and / or simultaneously charging the second battery pack with the first energy storage circuit and charging the second energy storage circuit with the first battery pack via a switching circuit. That is, in the first heating stage, the first and second energy storage circuits ensure that current always flows through the first and second battery packs, which helps maintain the stability of the current flowing through them, improving the heating efficiency of the batteries while ensuring relatively stable performance of the first and second battery packs.

[0012] 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 the battery, and the second end is connected to the negative terminal. The second heating stage further includes: repeatedly performing the steps of charging the second energy storage circuit from the second battery pack and charging the first battery pack from the second energy storage circuit N4 times via a switching circuit, where N4 is a positive integer greater than 1. The second energy storage circuit can also realize energy transfer from the second battery pack to the first battery pack, further improving the battery's heating efficiency.

[0013] In some embodiments, the second heating stage further includes: simultaneously charging the first energy storage circuit with the second battery pack and charging the first battery pack with the second energy storage circuit via a switching circuit; and / or simultaneously charging the first battery pack with the first energy storage circuit and charging the second energy storage circuit with the second battery pack via a switching circuit. That is, in the second heating stage, the first and second energy storage circuits ensure that current always flows through the first and second battery packs, which helps maintain the stability of the current flowing through them. This improves the heating efficiency of the batteries and maintains the energy balance between the first and second battery packs, while also ensuring relatively stable performance of both battery packs.

[0014] In some embodiments, the first energy storage circuit includes at least one inductor, and the second energy storage circuit includes a capacitor. Both the inductor and the capacitor have charging and discharging functions. The inductor can store a larger amount of electricity, improving the energy transfer efficiency from the first battery pack to the second battery pack, thereby improving the heating efficiency of the battery. Compared to the inductor, the capacitor is smaller in size and can achieve rapid charging and discharging. When the first battery pack and the inductor form a circuit to charge the inductor, the capacitor can act as a substitute power source, discharging into the second energy storage circuit. When the inductor and the second battery pack form a circuit to charge the second battery pack, the first battery pack can form a circuit with the capacitor to charge the capacitor. This ensures that current always flows through both the first and second battery packs during the first heating stage. Similarly, by using the inductor and capacitor, current also always flows through both the first and second battery packs when the battery is in the second heating stage, which helps maintain the stability of the current flowing through the first and second battery packs. Simultaneously, it keeps the size of the circuit for heating the battery smaller, saving costs.

[0015] In some embodiments, the method further includes: responding to a battery temperature lower than a preset temperature threshold, controlling the battery to enter a second heating stage to heat the battery via a switching circuit. The second heating stage includes: repeatedly performing the steps of the second battery pack charging the first energy storage circuit and the first energy storage circuit charging the first battery pack N2 times via the switching circuit, wherein, in the battery heating state, the inductor satisfies the volt-second product balance. That is, the volt-second product of the inductor in the first heating stage is equal to the volt-second product in the second heating stage. In this way, while achieving energy balance between the first battery pack and the second battery pack, the duration of the first heating stage and the duration of the second heating stage can be controlled to be equal or unequal. The current flowing through the inductor in the first heating stage and the current flowing through the inductor in the second heating stage can also be controlled to be equal or unequal, simplifying the battery heating control method.

[0016] In some embodiments, 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 a first battery pack, the lower bridge arm being connected to the negative terminal of a second battery pack, the negative terminal of the first battery pack being connected to the positive terminal of the second battery pack, a first terminal of a first energy storage circuit being connected between the upper and lower bridge arms, and a second terminal of the first energy storage circuit being connected between the first and second battery packs; wherein, by repeatedly performing N1 cycles of charging the first energy storage circuit from the first battery pack and charging the second battery pack from the first energy storage circuit through the switching circuit includes: sequentially and alternately performing a first step and a second step; the first step includes: controlling the upper bridge arm to be on and the lower bridge arm to be off, and the second step includes: controlling the lower bridge arm to be on and the upper bridge arm to be off. By controlling the sequential and alternate conduction of the upper and lower bridge arms, energy transfer from the first battery pack to the second battery pack can be realized, which is simple to operate and simplifies the control method of circuit heating.

[0017] In some embodiments, the method further includes, when the battery is controlled to be in a second heating stage to heat the battery via a switching circuit, repeatedly performing N2 cycles of charging the first energy storage circuit by the second battery pack and charging the first battery pack by the first energy storage circuit via the switching circuit, comprising sequentially and alternately performing the second step and the first step. In this way, the switching circuit only needs to be configured with a bridge arm, without requiring other circuit structures, to control the battery to be in the second heating stage, achieving energy balance between the first and second battery packs, simplifying the circuit structure and the battery heating control method, and improving the reliability of the battery heating control method.

[0018] An embodiment of the second aspect of this application provides a battery heating circuit, including: a switching circuit, a first terminal of which is connected to the positive terminal of the battery, and a second terminal of which is connected to the negative terminal of the battery, the battery including a first battery pack and a second battery pack connected in series; a first energy storage circuit, a first terminal of which is connected to the switching circuit, and a second terminal of which is connected to the midpoint between the first battery pack and the second battery pack; and a controller configured to: acquire the temperature of the battery; and, in response to the battery temperature being lower than a preset temperature threshold, control the battery to be in a first heating stage to heat the battery via the switching circuit, wherein the first heating stage includes: repeatedly executing the steps of the first battery pack charging the first energy storage circuit and the first energy storage circuit charging the second battery pack N1 times via the switching circuit, where N1 is a positive integer greater than 1. Repeating the steps of the first battery pack charging the first energy storage circuit and the first energy storage circuit charging the second battery pack N1 times in the first heating stage enables self-heating of the battery without the need for external heating equipment, greatly reducing the cost of the battery heating circuit. Simultaneously, it also improves the efficiency of energy transfer from the first battery pack to the second battery pack, thereby improving the heating efficiency of the battery through the first energy storage circuit.

[0019] In some embodiments, the controller is further configured to: in response to a battery temperature lower than a preset temperature threshold, control the battery to enter a second heating stage via a switching circuit to heat the battery. The second heating stage includes: repeatedly executing the steps of the second battery pack charging the first energy storage circuit and the first energy storage circuit charging the first battery pack N2 times via the switching circuit, where N2 is a positive integer greater than 1. This enables energy exchange between the first and second battery packs, maintaining energy balance between them.

[0020] In some embodiments, the battery heating circuit further includes a second energy storage circuit, a first terminal of which is connected to the positive terminal of the battery, and a second terminal of which is connected to the negative terminal of the battery. The controller is further configured to: during the first heating phase, repeatedly execute the steps of the first battery pack charging the second energy storage circuit and the second energy storage circuit charging the second battery pack N3 times via a switching circuit, where N3 is a positive integer greater than 1. The second energy storage circuit can also realize energy transfer from the first battery pack to the second battery pack, further improving the battery heating efficiency.

[0021] In some embodiments, the controller is further configured to: during the first heating phase, simultaneously execute the first battery pack charging the first energy storage circuit and the second energy storage circuit charging the second battery pack via a switching circuit; and / or during the first heating phase, simultaneously execute the first energy storage circuit charging the second battery pack and the first battery pack charging the second energy storage circuit via a switching circuit. Thus, during the first heating phase, current flows continuously through the first and second energy storage circuits, which helps maintain the stability of the current flowing through the first and second battery packs, improving the heating efficiency of the batteries while ensuring relatively stable performance of the first and second battery packs.

[0022] In some embodiments, the battery heating circuit further includes a second energy storage circuit, a first terminal of which is connected to the positive terminal of the battery, and a second terminal of which is connected to the negative terminal of the battery. The controller is further configured to, during a second heating phase, repeatedly execute the steps of the second battery pack charging the second energy storage circuit and the second energy storage circuit charging the first battery pack N4 times via a switching circuit, where N4 is a positive integer greater than 1. The second energy storage circuit can also realize energy transfer from the second battery pack to the first battery pack, further improving the battery heating efficiency.

[0023] In some embodiments, the controller is configured to: during the second heating phase, simultaneously execute the second battery pack charging the first energy storage circuit and the second energy storage circuit charging the first battery pack via a switching circuit; and / or during the second heating phase, simultaneously execute the first energy storage circuit charging the first battery pack and the second battery pack charging the second energy storage circuit via a switching circuit. Thus, during the second heating phase, current flows continuously through the first and second energy storage circuits, which helps maintain the stability of the current flowing through the first and second battery packs. This improves the heating efficiency of the batteries and maintains the energy balance between the first and second battery packs, resulting in more stable performance of both battery packs.

[0024] In some embodiments, the first energy storage circuit includes at least one inductor, and the second energy storage circuit includes a capacitor. Both the inductor and the capacitor have charging and discharging functions. The inductor can store a larger amount of energy, improving the energy transfer efficiency from the first battery pack to the second battery pack, thereby improving the heating efficiency of the battery. Compared to the inductor, the capacitor is smaller in size and can achieve rapid charging and discharging, ensuring that current always flows through both the first and second battery packs during the first heating stage. When the battery is in the second heating stage, ensuring that current always flows through both the first and second battery packs during this stage helps maintain the stability of the current flowing through them. Simultaneously, it reduces the size and weight of the battery heating circuit, saving costs.

[0025] In some embodiments, 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 a first battery pack, the lower bridge arm being connected to the negative terminal of a second battery pack, the negative terminal of the first battery pack being connected to the positive terminal of the second battery pack, wherein a first terminal of a first energy storage circuit is connected between the upper and lower bridge arms, and a second terminal of the first energy storage circuit is electrically connected between the first and second battery packs, and the controller is configured to sequentially and alternately execute a first step and a second step to control the battery in a first heating stage; wherein the first step includes: controlling the upper bridge arm to conduct and the lower bridge arm to turn off, and the second step includes: controlling the lower bridge arm to conduct and the upper bridge arm to turn off. This simplifies the circuit structure, simplifies circuit control, and improves the reliability of the method of heating the battery through this battery heating circuit.

[0026] In some embodiments, the controller is further configured to control the battery to be in a second heating stage via a switching circuit. In this case, the controller is configured to alternately execute the second step and the first step sequentially to control the battery to be in the second heating stage. In this way, the switching circuit only needs to provide a bridge arm, without requiring other circuit structures, to control the battery to be in the second heating stage, achieving energy balance between the first and second battery packs, simplifying the circuit structure and control method.

[0027] In some embodiments, the circuit further includes: multiple neutral lines connected in parallel, with a first end of the neutral line connected to a second end of the first energy storage circuit, and the second end of the neutral line connected between the first battery pack and the second battery pack. This allows current to be transmitted through multiple neutral lines, thereby increasing the current flowing through the first energy storage circuit, improving the efficiency of energy transfer between the first battery pack and the second battery pack through the first energy storage circuit, and further improving the heating efficiency of the batteries.

[0028] In some embodiments, there are multiple bridge arms connected in parallel. The first energy storage circuit includes multiple first inductors connected in parallel, with each first inductor corresponding to one of the multiple bridge arms. In this way, energy transfer can be achieved between the first battery pack and the second battery pack through the multiple first inductors. Furthermore, the parallel connection of the multiple first inductors can suppress high-frequency noise in the circuit, making the circuit current more stable and further enhancing the battery's heating efficiency.

[0029] In some embodiments, the first energy storage circuit further includes a second inductor, which is connected in series with a plurality of first inductors that are connected in parallel. By connecting the second inductor in series, the energy stored by the first energy storage circuit can be increased, the energy transfer efficiency between the first battery pack and the second battery pack can be improved, thereby further enhancing the heating efficiency of the battery.

[0030] An embodiment of the third aspect of this application provides a battery system that includes the battery heating circuit described in the above embodiments.

[0031] An embodiment of the fourth aspect of this application provides an electrical device that includes the battery system described in the above embodiments, the battery system being used to provide electrical energy.

[0032] 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

[0033] 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.

[0034] Figure 1 is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0035] Figure 2 is a schematic diagram of the structure of a battery heating circuit according to some embodiments of this application;

[0036] Figure 3 is a schematic flowchart of one of the battery heating methods according to some embodiments of this application;

[0037] Figure 4 is one of the waveforms of the current flowing through the first energy storage circuit in a battery heating method according to some embodiments of this application;

[0038] Figure 5 is one of the waveforms of the current flowing through the first energy storage circuit in a battery heating method;

[0039] Figure 6 is a second schematic flowchart of a battery heating method according to some embodiments of this application;

[0040] Figure 7 is a second waveform diagram of the current flowing through the first energy storage circuit in a battery heating method according to some embodiments of this application;

[0041] Figure 8 is a second waveform diagram of the current flowing through the first energy storage circuit in a battery heating method;

[0042] Figure 9 is a second schematic diagram of the battery heating circuit in some embodiments of this application;

[0043] Figure 10 is one of the schematic diagrams of the current path when the battery is controlled in the first heating stage in the battery heating method of some embodiments of this application;

[0044] Figure 11 is a second schematic diagram of the current path when the battery is controlled in the first heating stage in the battery heating method of some embodiments of this application;

[0045] Figure 12 is one of the schematic diagrams of the current path when the battery is controlled in the second heating stage in the battery heating method of some embodiments of this application;

[0046] Figure 13 is a second schematic diagram of the current path when the battery is controlled to be in the second heating stage in the battery heating method of some embodiments of this application;

[0047] Figure 14 is a circuit diagram corresponding to the execution of the first step in the battery heating method of some embodiments of this application to put the battery into a first heating stage;

[0048] Figure 15 is a circuit diagram corresponding to the execution of the second step in the battery heating method of some embodiments of this application to put the battery into the first heating stage;

[0049] Figure 16 is a circuit diagram corresponding to the execution of the second step in the battery heating method of some embodiments of this application to put the battery into a second heating stage;

[0050] Figure 17 is a circuit diagram corresponding to the execution of the first step in the battery heating method of some embodiments of this application to put the battery into the second heating stage;

[0051] Figure 18 is a schematic diagram of the structure of a battery heating circuit according to some embodiments of this application.

[0052] Explanation of reference numerals in the attached drawings: Vehicle 1000; Battery 100; Switching circuit 101; First energy storage circuit 102; Second energy storage circuit 103; Vehicle controller 200; Motor 300; First battery pack 11; Second battery pack 12; Bridge arm 20; Current sensor 23; First connector 24; Second connector 25; Neutral line 30; First freewheeling diode D1; Second freewheeling diode D2; First switch K1; Second switch K2; Third switch K3; First inductor L1; Second inductor L2; First resistor R1; Upper bridge arm switch V1; Lower bridge arm switch V2; Fourth switch V3. Detailed Implementation

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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).

[0059] To address the issue of low charging efficiency of batteries in low-temperature environments, batteries are typically heated until their temperature reaches the required level before charging.

[0060] In related technologies, external heating devices are typically used to heat the battery, such as PTC (Positive Temperature Coefficient) thermistors. This heating method relies on the principle of heat transfer to achieve heat exchange between the external heating device and the battery. However, this method has low heating efficiency and can easily lead to uneven temperatures between the outside and inside of the battery.

[0061] Based on the above considerations, a battery heating method is designed. In response to the battery temperature being lower than a preset temperature threshold, the battery is controlled to be in a first heating stage by a switching circuit to heat the battery. The first heating stage includes: repeatedly executing N1 times the first battery pack charging the first energy storage circuit and the first energy storage circuit charging the second battery pack by the switching circuit.

[0062] In the first heating stage, energy is transferred from the first battery pack to the second battery pack, achieving self-heating for both packs. This results in a uniform and rapid temperature increase for both battery packs without the need for external heating equipment, reducing costs. Furthermore, repeating the steps of charging the first energy storage circuit from the first battery pack to the second battery pack N1 times during the first heating stage significantly improves the efficiency of energy transfer from the first battery pack to the second battery pack compared to performing this step only once. This, in turn, enhances the heating efficiency of the battery heating via the first energy storage circuit.

[0063] The battery heating method disclosed in this application can be used, but is not limited to, for heating batteries in electrical devices such as vehicles, ships, or aircraft.

[0064] 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.

[0065] 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.

[0066] 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 a step 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.

[0067] In some embodiments of this application, the battery 100 can not only serve as a step power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0068] Referring to Figures 2 and 3, this application embodiment provides a battery heating method. The battery includes a first battery pack 11 and a second battery pack 12 connected in series. The positive terminal of the battery is connected to a first terminal of a switching circuit 101, and the negative terminal of the battery is connected to a second terminal of the switching circuit 101. The switching circuit 101 is also connected to a first terminal of a first energy storage circuit 102, and the second terminal of the first energy storage circuit 102 is connected to the midpoint between the first battery pack 11 and the second battery pack 12. The battery heating method includes:

[0069] Step 110: Obtain the battery temperature;

[0070] Step 120: In response to the battery temperature being lower than a preset temperature threshold, the battery is controlled to enter a first heating stage to heat the battery via the switching circuit 101. The first heating stage includes: repeatedly executing the steps of the first battery pack 11 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the second battery pack 12 N1 times via the switching circuit 101, where N1 is a positive integer greater than 1.

[0071] The switching circuit 101 may include a first connection point, a second connection point, and a third connection point interconnected by switching elements. The first connection point may be connected to the positive terminal of the battery, the second connection point may be connected to the negative terminal of the battery, and the third connection point may be connected to a first terminal of the first energy storage circuit. The first connection point may be a node between the first switching circuit and the positive terminal of the battery, the second connection point may be a node between the switching circuit 101 and the negative terminal of the battery 100, and the third connection point may be a node between the first energy storage circuit 102 and the switching circuit 101.

[0072] The first connection point, the second connection point, and the third connection point are interconnected by a switching element; that is, any two of the first, second, and third connection points can be connected by a switching element. For example, when the first and second connection points are connected by a switching element, a circuit is formed between the first and second connection points. Thus, the switching circuit 101 allows the first energy storage circuit 102 to form a loop with both the first battery pack 11 and the second battery pack 12. For example, the positive terminal of the first battery pack 11 is connected to the first connection point, and the negative terminal of the second battery pack 12 is connected to the second connection point. The positive terminals of the first battery pack 11 and the second battery pack 12 are connected. When the first and third connection points are connected, the first energy storage circuit 102 and the first battery pack 11 form a loop; when the second and third connection points are connected, the first energy storage circuit 102 and the second battery pack 12 form a loop.

[0073] It is understandable that the first connection point, the second connection point, and the third connection point can all be connected.

[0074] In step 110, a temperature sensor can be used to obtain the battery temperature. Obtaining the battery temperature can involve obtaining the temperature of the first battery pack 11 and the temperature of the second battery pack 12.

[0075] In step 120, the preset temperature threshold can be a specific temperature value or a range. The preset temperature threshold can be adjusted according to the battery type. The method for setting the preset temperature threshold 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 decreases significantly, and this value can be determined as the preset temperature threshold.

[0076] In some embodiments, the battery may be controlled to be in a first heating phase in response to the temperature of either the first battery pack 11 or the second battery pack 12 being lower than a preset temperature threshold.

[0077] In other embodiments, the battery may be controlled to be in a first heating stage in response to the fact that the temperatures of both the first battery pack 11 and the second battery pack 12 are lower than a preset temperature threshold.

[0078] The value of N1 can be set according to the preset temperature threshold value. The steps of the first battery pack 11 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the second battery pack 12 can be executed multiple times in advance until the temperature of the first battery pack 11 and the second battery pack 12 are both greater than or equal to the preset temperature threshold. The number of times this is executed is used as the value of N1.

[0079] In the first heating stage, the first battery pack 11 forms a loop through the switching circuit 101 and the first energy storage circuit 102, allowing the first battery pack 11 to charge the first energy storage circuit 102, which then stores energy. Subsequently, the second battery pack 12 forms a loop through the switching circuit 101 and the first energy storage circuit 102, allowing the first energy storage circuit 102 to release its stored energy to charge the second battery pack 12. Thus, during the first heating stage, current flows between the first battery pack 11 and the second battery pack 12, thereby heating both battery packs. Repeating this process allows the first battery pack 11 to maintain a longer discharge time and the second battery pack 12 to maintain a longer charging time. Furthermore, compared to performing the process only once, repeating the process reduces the rate of change of current flowing through the first energy storage circuit 102, thereby reducing the current frequency, decreasing current ripple, and mitigating the high-frequency whistling problem in the battery heating circuit. This achieves low-frequency heating of the battery, improving heating efficiency.

[0080] Furthermore, as shown in Figure 4, Figure 4 shows the waveform of the current through the first energy storage circuit 102 when the first battery pack 11 charges the first energy storage circuit 102 and the first energy storage circuit 102 charges the second battery pack 12 repeatedly during the first heating stage T1.

[0081] As shown in Figure 4, during the charging of the first energy storage circuit 102 by the first battery pack 11, the current in the first energy storage circuit 102 gradually increases from 0 to a positive first current I. up When the first energy storage circuit 102 is charging the second battery pack 12, the direction of current flow through the first energy storage circuit 102 remains unchanged. However, because the first energy storage circuit 102 releases energy, the current in the first energy storage circuit 102 changes from the positive first current I. up The second current I gradually decreases to a positive value. down .

[0082] The current in the first energy storage circuit 102 decreases to a positive second current I. down At any given time, the above process is repeated, that is, the first battery pack 11 charges the first energy storage circuit 102 again, causing the current in the first energy storage circuit 102 to rise to I again. upThis ensures that the current in the first energy storage circuit 102 is at a positive first current I. up and the positive second current I down The current alternates between these states until the first heating stage ends, at which point the current in the first energy storage circuit 102 becomes 0.

[0083] Figure 5 shows the waveform of the current through the first energy storage circuit 102 when the first heating stage T1 alternately performs the charging of the first energy storage circuit 102 by the first battery pack 11 and the charging of the second battery pack 12 by the first energy storage circuit 102 once.

[0084] As shown in Figure 5, during the charging of the first energy storage circuit 102 by the first battery pack 11, the current in the first energy storage circuit 102 gradually increases from 0 to a positive first current I. up When the first energy storage circuit 102 is charging the second battery pack 12, the current in the first energy storage circuit 102 changes from a positive first current I. up As the first energy storage circuit 102 is charged by the first battery pack 11 only once during the first heating stage, the first energy storage circuit 102 will continue to release energy until the current in the first energy storage circuit 102 decreases to 0.

[0085] As can be seen from the above, in the case shown in Figure 4, during the first heating stage, the current passing through the first energy storage circuit 102 is a positive first current I. up and the positive second current I down The current varies between these values, and in the case shown in Figure 5, during the first heating stage, the current through the first energy storage circuit 102 is at a positive first current I. up The current changes between 0 and 0. That is, the rate of change of the current through the first energy storage circuit 102 in the case shown in Figure 4 is much smaller than the rate of change of the current through the first energy storage circuit 102 in the case shown in Figure 5, thereby reducing the frequency of the current.

[0086] In the above technical solution, the steps of charging the first battery pack 11 to the first energy storage circuit 102 and charging the second battery pack 12 by the first energy storage circuit 102 are repeated N1 times during the first heating stage. This allows the first battery pack 11 to maintain a longer discharge time and the second battery pack 12 to maintain a longer charging time, thereby improving heating efficiency. Furthermore, it can reduce the rate of change of current flowing through the first energy storage circuit 102, thus reducing the current frequency and consequently reducing the current ripple flowing through the first energy storage circuit 102, thereby improving the heating efficiency of the battery through the first energy storage circuit 102.

[0087] Referring to Figure 6, according to some embodiments of this application, the method further includes:

[0088] Step 130: In response to the battery temperature being lower than a preset temperature threshold, the battery is controlled to enter a second heating stage via the switching circuit 101 to heat the battery. The second heating stage includes: repeatedly executing the steps of the second battery pack 12 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the first battery pack 11 N2 times via the switching circuit 101, where N2 is a positive integer greater than 1.

[0089] The values ​​of N2 and N1 can be the same or different. The values ​​of N2 and N1 can be set according to the preset temperature threshold and the battery type. The steps of the first battery pack 11 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the second battery pack 12, as well as the steps of the second battery pack 12 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the first battery pack 11, can be performed multiple times in advance until the temperature of the first battery pack 11 and the second battery pack 12 are both greater than or equal to the preset temperature threshold. At this time, the number of times the first heating stage is performed and the number of times the second heating stage is performed can be used as the number of times N1 and N2 are performed, respectively.

[0090] In some embodiments, the battery may be controlled to enter a second heating stage in response to the temperature of one of the first battery pack 11 and the second battery pack 12 being lower than a preset temperature threshold.

[0091] In other embodiments, the battery may be controlled to enter a second heating stage in response to the fact that the temperatures of both the first battery pack 11 and the second battery pack 12 are lower than a preset temperature threshold.

[0092] In the second heating stage, the second battery pack 12 charges the first energy storage circuit 102 to store energy. Subsequently, the first energy storage circuit 102 releases the stored energy to charge the first battery pack 11. Repeating the above process reduces the rate of change of current flowing through the first energy storage circuit 102, thereby reducing the current frequency and achieving low-frequency heating of the battery. The reason is as described above in the relevant description of the first heating stage, and will not be repeated below.

[0093] In some embodiments, the first heating stage and the second heating stage can be performed alternately, that is, after the first heating stage ends, the second heating stage begins directly.

[0094] Figure 7 shows the waveform of the current through the first energy storage circuit 102 when the first battery pack 11 alternately charges the first energy storage circuit 102 and the first energy storage circuit 102 charges the second battery pack 12 during the first heating phase T1, and the second energy storage circuit 102 alternately charges the first energy storage circuit 102 and the first energy storage circuit 102 charges the first battery pack 11 during the second heating phase T2.

[0095] As shown in Figure 7, after the first heating stage T1 ends, the current in the first energy storage circuit 102 becomes 0. After the second heating stage T2 begins, the second battery pack 12 charges the first energy storage circuit 102, causing the current in the first energy storage circuit 102 to gradually increase. Since in the second heating stage T2, the second battery pack 12 charges the first energy storage circuit 102, and the first energy storage circuit 102 charges the first battery pack 11, the current flowing through the first energy storage circuit 102 is reversed compared to the first heating stage, therefore the current is negative. The current in the first energy storage circuit 102 is at a negative first current - I. up and the negative second current -I down The current alternates between these phases until the second heating phase T2 ends, at which point the current in the first energy storage circuit 102 becomes 0.

[0096] Figure 8 shows the waveform of the current through the first energy storage circuit 102 when the first heating stage T1 alternates between charging the first battery pack 11 to the first energy storage circuit 102 and charging the second battery pack 12 once, and the second heating stage T2 alternates between charging the second battery pack 12 to the first energy storage circuit 102 and charging the first battery pack 11 once.

[0097] As shown in Figure 8, during the second heating stage, the current passing through the first energy storage circuit 102 varies between a negative first current -Iup and 0.

[0098] It is not difficult to see that, in the case shown in Figure 8, during the first heating stage T1 and the second heating stage T2, the current through the first energy storage circuit 102 is a positive first current I. up and the negative first current -I up The current varies between the two phases. In the case shown in Figure 7, during the first heating stage and the second heating stage, the current through the first energy storage circuit 102 is in the positive first current I. up and the positive second current I down Alternating between, or in the negative first current -I up and the negative second current -I down The alternating changes between the two make the rate of change of the current through the first energy storage circuit 102 much smaller than the rate of change of the current through the first energy storage circuit 102 as shown in Figure 8, thereby greatly reducing the current frequency through the first energy storage circuit 102.

[0099] In the above technical solution, during the second heating stage, the energy of the second battery pack 12 is transferred to the first battery pack 11, thereby heating the first battery pack 11 and the second battery pack 12. This allows the first battery pack 11 and the second battery pack 12 to exchange energy, thus maintaining the energy balance of the first battery pack 11 and the second battery pack 12 while heating them.

[0100] Referring to Figure 9, according to some embodiments of this application, a second energy storage circuit 103 is also connected in parallel across the two ends of the battery, wherein the first end of the second energy storage circuit 103 is connected to the positive terminal of the battery, and the second end of the second energy storage circuit 103 is connected to the negative terminal of the battery.

[0101] The first heating stage also includes: repeatedly performing the steps of charging the second energy storage circuit 103 by the first battery pack 11 and charging the second battery pack 12 by the second energy storage circuit 103 through the switching circuit 101 N3 times, where N3 is a positive integer greater than 1.

[0102] The second energy storage circuit 103 is connected in parallel across the two ends of the battery, and the switching circuit 101 is also connected in parallel across the two ends of the battery. That is, the second energy storage circuit 103 and the switching circuit 101 are connected in parallel, and the switching circuit 101 is connected to the first energy storage circuit 102. In this way, the second energy storage circuit 103 can be connected to the midpoint of the first battery pack 11 and the second battery pack 12 through the switching circuit 101 and the first energy storage circuit 102, thereby enabling the steps of the first battery pack 11 charging the second energy storage circuit 103 and the second energy storage circuit 103 charging the second battery pack 12 to be repeated N1 times. The value of N3 can be the same as or different from the value of N1.

[0103] During the first heating stage, the first battery pack 11 can form a circuit with the second energy storage circuit 103 through the switching circuit 101 and the first energy storage circuit 102, so that the first battery pack 11 charges the second energy storage circuit 103, and the second energy storage circuit 103 stores energy. The second battery pack 12 can also form a circuit with the second energy storage circuit 103 through the switching circuit 101 and the first energy storage circuit 102, so that the second energy storage circuit 103 releases energy to charge the second battery pack 12.

[0104] In some embodiments, during the first heating stage, the first battery pack 11 can simultaneously charge the first energy storage circuit 102 and the second energy storage circuit 103, and the first energy storage circuit 102 can simultaneously charge the second battery pack 12 and the second energy storage circuit 103 can simultaneously charge the second battery pack 12.

[0105] The second energy storage circuit may include, but is not limited to, components with charging and discharging functions such as inductors or capacitors.

[0106] For example, the switching circuit 101 may include a bridge arm, which includes an upper bridge arm and a lower bridge arm. The first end of the first energy storage circuit 102 is connected to the midpoint between the upper bridge arm and the lower bridge arm. Both the first energy storage circuit 102 and the second energy storage circuit 103 include inductors.

[0107] During the first heating phase, the steps of turning on the lower bridge arm and turning on the upper bridge arm are performed alternately and repeatedly.

[0108] During the conduction of the lower bridge arm, the first battery pack 11, the second energy storage circuit 103, the lower bridge arm, and the first energy storage circuit 102 form a loop. Current flows out from the positive terminal of the first battery pack 11, flows through the second energy storage circuit 103, the lower bridge arm, and the first energy storage circuit 102 in sequence, and then flows back to the negative terminal of the first battery pack 11, so that the first battery pack 11 charges both the first energy storage circuit 102 and the second energy storage circuit 103 at the same time.

[0109] During the conduction of the upper bridge arm, the second energy storage circuit 103, the upper bridge arm, the first energy storage circuit 102, and the second battery pack 12 form a loop. The second energy storage circuit 103 and the first energy storage circuit 102 release energy to the second battery pack 12. Current flows from the second energy storage circuit 103 and the first energy storage circuit 102 to the positive terminal of the second battery pack 12 and flows out from the negative terminal of the second battery pack 12, so that the second energy storage circuit 103 and the first energy storage circuit 102 simultaneously charge the second battery pack 12.

[0110] It is understood that in some other embodiments, during the first heating stage, the charging of the first energy storage circuit 102 by the first battery pack 11 and the charging of the second energy storage circuit 103 by the first battery pack 11 may not be performed simultaneously, and the charging of the second battery pack 12 by the first energy storage circuit 102 and the charging of the second battery pack 12 by the second energy storage circuit 103 may also not be performed simultaneously.

[0111] In the above technical solution, during the first heating stage, the energy transfer from the first battery pack 11 to the second battery pack 12 can be achieved through the second energy storage circuit 103, thereby improving the energy transfer efficiency and further improving the heating efficiency of the battery.

[0112] According to some embodiments of this application, the first heating stage further includes: simultaneously charging the first energy storage circuit 102 with the first battery pack 11 and charging the second energy storage circuit 103 with the second battery pack 12 via the switching circuit 101; and / or simultaneously charging the second battery pack 12 with the first energy storage circuit 102 and charging the second energy storage circuit 103 with the first battery pack 11 via the switching circuit 101.

[0113] In other words, while the first battery pack 11 and the first energy storage circuit 102 form a loop so that the first battery pack 11 charges the first energy storage circuit 102, the second energy storage circuit 103 can form a loop with the second battery pack 12 so that the second energy storage circuit 103 charges the second battery pack 12, thereby allowing current to flow through the second battery pack 12.

[0114] While the first energy storage circuit 102 and the second battery pack 12 form a circuit to charge the second battery pack 12, the second energy storage circuit 103 can form a circuit with the first battery pack 11 to charge the second energy storage circuit 103, thereby allowing current to flow through the first battery pack 11. Thus, during the first heating phase, current continuously flows through both the first battery pack 11 and the second battery pack 12. Furthermore, during the first heating phase, both the first energy storage circuit 102 and the second energy storage circuit 103 can transfer energy from the first battery pack 11 to the second battery pack 12, improving the heating efficiency of both battery packs.

[0115] In the above technical solution, during the first heating stage, the first energy storage circuit 102 and the second energy storage circuit 103 ensure that current always flows through the first battery pack 11 and the second battery pack 12, which helps to maintain the stability of the current flowing through the first battery pack 11 and the second battery pack 12. This improves the heating efficiency of the batteries and makes the performance of the first battery pack 11 and the second battery pack 12 more stable.

[0116] According to some embodiments of this application, a second energy storage circuit 103 is also connected in parallel across the two ends of the battery, wherein the first end of the second energy storage circuit 103 is connected to the positive terminal of the battery, and the second end of the second energy storage circuit 103 is connected to the negative terminal of the battery.

[0117] The second heating stage also includes:

[0118] The switching circuit 101 repeats the steps of charging the second battery pack 12 to the second energy storage circuit 103 and charging the first battery pack 11 by the second battery pack 12 N4 times, where N4 is a positive integer greater than 1.

[0119] During the second heating stage, the second battery pack 12 can form a circuit with the second energy storage circuit 103 through the switching circuit 101 and the first energy storage circuit 102, so that the second battery pack 12 charges the second energy storage circuit 103, and the second energy storage circuit 103 stores energy. The first battery pack 11 can also form a circuit with the second energy storage circuit 103 through the switching circuit 101 and the first energy storage circuit 102, so that the second energy storage circuit 103 releases energy to charge the first battery pack 11. The value of N4 can be the same as or different from the value of N2.

[0120] In some embodiments, during the second heating stage, the second battery pack 12 can simultaneously charge the first energy storage circuit 102 and the second energy storage circuit 103, and the first energy storage circuit 102 can simultaneously charge the first battery pack 11 and the second energy storage circuit 103 can simultaneously charge the first battery pack 11.

[0121] For example, the switching circuit 101 may include a bridge arm, and both the first energy storage circuit 102 and the second energy storage circuit 103 include inductors.

[0122] During the second heating phase, the steps of turning on the upper bridge arm and turning on the lower bridge arm are performed alternately and repeatedly.

[0123] During the conduction of the upper bridge arm, the second battery pack 12, the first energy storage circuit 102, the upper bridge arm, and the second energy storage circuit 103 form a loop. Current flows out from the positive terminal of the second battery pack 12, flows through the first energy storage circuit 102, the upper bridge arm, and the second energy storage circuit 103 in sequence, and then flows back to the negative terminal of the second battery pack 12, so that the second battery pack 12 charges both the first energy storage circuit 102 and the second energy storage circuit 103 at the same time.

[0124] During the conduction of the lower bridge arm, the first battery pack 11, the first energy storage circuit 102, the lower bridge arm, and the second energy storage circuit 103 form a loop. The first energy storage circuit 102 and the second energy storage circuit 103 release energy to the first battery pack 11. Current flows from the first energy storage circuit 102 and the second energy storage circuit 103 to the positive terminal of the first battery pack 11 and flows out from the negative terminal of the first battery pack 11, so that the first energy storage circuit 102 and the second energy storage circuit 103 simultaneously charge the first battery pack 11.

[0125] In other embodiments, during the second heating stage, the charging of the first energy storage circuit 102 by the second battery pack 12 and the charging of the second energy storage circuit 103 by the second battery pack 12 may not be performed simultaneously, and the charging of the first battery pack 11 by the first energy storage circuit 102 and the charging of the first battery pack 11 by the second energy storage circuit 103 may also not be performed simultaneously.

[0126] In the above technical solution, the second energy storage circuit 103 can also realize the energy transfer from the second battery pack 12 to the first battery pack 11, further improving the heating efficiency of the battery.

[0127] According to some embodiments of this application, the second heating stage further includes: simultaneously executing the second battery pack 12 charging the first energy storage circuit 102 and the second energy storage circuit 103 charging the first battery pack 11 through the switching circuit 101; and / or simultaneously executing the first energy storage circuit 102 charging the first battery pack 11 and the second battery pack 12 charging the second energy storage circuit 103 through the switching circuit 101.

[0128] In other words, while the second battery pack 12 and the first energy storage circuit 102 form a loop so that the second battery pack 12 charges the first energy storage circuit 102, the second energy storage circuit 103 can form a loop with the first battery pack 11 so that the second energy storage circuit 103 charges the first battery pack 11, thereby allowing current to flow through the first battery pack 11.

[0129] While the first energy storage circuit 102 and the first battery pack 11 form a circuit to charge the first battery pack 11, the second energy storage circuit 103 can form a circuit with the second battery pack 12 to charge the second energy storage circuit 103, thereby allowing current to flow through the second battery pack 12. Thus, during the second heating phase, current continuously flows through both the first battery pack 11 and the second battery pack 12. Furthermore, during the second heating phase, both the first energy storage circuit 102 and the second energy storage circuit 103 can transfer energy from the second battery pack 12 to the first battery pack 11, improving the heating efficiency of both the first battery pack 11 and the second battery pack 12.

[0130] In the above technical solution, during the second heating stage, the first energy storage circuit 102 and the second energy storage circuit 103 ensure that current always flows through the first battery pack 11 and the second battery pack 12. This helps to maintain the stability of the current flowing through the first battery pack 11 and the second battery pack 12, thereby improving the heating efficiency of the battery and maintaining the energy balance of the first battery pack 11 and the second battery pack 12, while also making the performance of the first battery pack 11 and the battery pack more stable.

[0131] According to some embodiments of this application, the first energy storage circuit 102 includes at least one inductor, and the second energy storage circuit 103 includes a capacitor.

[0132] In some embodiments, the first energy storage circuit 102 may include an inductor.

[0133] In other embodiments, the first energy storage circuit 102 may also include multiple inductors, which may be connected in parallel or in series, or some of the multiple inductors may be connected in parallel and then connected in series with the remaining inductors.

[0134] Both inductors and capacitors have charging and discharging functions. The first energy storage circuit 102 includes at least one inductor, and the second energy storage circuit 103 includes a capacitor. This enables the first battery pack 11 to charge the first energy storage circuit 102 and the second energy storage circuit 103 to charge the second battery pack 12 simultaneously through the switching circuit 101, and the first energy storage circuit 102 to charge the second battery pack 12 and the first battery pack 11 to charge the second energy storage circuit 103 simultaneously through the switching circuit 101.

[0135] As shown in Figure 10, a capacitor is connected in parallel across the two ends of the battery. In the first battery pack 11, a circuit is formed through the switching circuit 101 and the inductor. During the charging of the inductor, the capacitor acts as a substitute for the power source. Because the switching circuit 101 and the inductor are connected, the capacitor can also form a circuit with the second battery pack 12 through the switching circuit 101 and the inductor. The current in this circuit, following the current flow in the switching circuit 101 and the inductor, charges the second battery pack 12. The solid lines with arrows in Figure 10 show the current path of the first battery pack 11 charging the inductor, and the dashed lines with arrows show the current path of the capacitor charging the second battery pack 12.

[0136] As shown in Figure 11, the second battery pack 12 forms a circuit through the switching circuit 101 and the inductor. During the charging of the second battery pack 12 by the inductor, the switching circuit 101 and the inductor are connected, allowing the capacitor to form a circuit with the first battery pack 11 through the switching circuit 101 and the inductor. The current in this circuit, flowing along the switching circuit 101 and the inductor, charges the capacitor in the first battery pack 11. The solid line with arrows in Figure 11 shows the current path of the inductor charging the second battery pack 12 through the switching circuit 101, while the dashed line with arrows shows the current path of the first battery pack 11 charging the capacitor.

[0137] Similarly, when the battery is in the second heating stage, the second battery pack 12 can charge the first energy storage circuit 102 and the second energy storage circuit 103 can charge the first battery pack 11 simultaneously through the switching circuit 101, and the first energy storage circuit 102 can charge the first battery pack 11 and the second battery pack 12 can charge the second energy storage circuit 103 simultaneously through the switching circuit 101.

[0138] As shown in Figure 12, during the charging of the inductor, the second battery pack 12 forms a circuit through the switching circuit 101 and the inductor. Simultaneously, the capacitor forms a circuit with the first battery pack 11 through the switching circuit 101 and the inductor. The current in this circuit, flowing along the current in the switching circuit 101 and the inductor, charges the first battery pack 11. The solid lines with arrows in Figure 12 show the current path of the second battery pack 12 charging the inductor, while the dashed lines with arrows show the current path of the capacitor charging the first battery pack 11.

[0139] As shown in Figure 13, the first battery pack 11 forms a circuit through the switching circuit 101 and the inductor, so that during the charging of the first battery pack 11 by the inductor, the capacitor can form a circuit with the second battery pack 12 through the switching circuit 101 and the inductor, and the current in this circuit, flowing along the switching circuit 101 and the inductor, causes the second battery pack 12 to charge the capacitor. The solid line with arrows in Figure 13 shows the current path of the inductor charging the first battery pack 11 through the switching circuit 101, and the dashed line with arrows shows the current path of the second battery pack 12 charging the capacitor.

[0140] In the above technical solution, the inductor can store a larger amount of electricity, which can improve the energy transfer efficiency from the first battery pack 11 to the second battery pack 12, thereby improving the heating efficiency of the battery. Compared with the inductor, the capacitor is smaller in size and can achieve rapid charging and discharging, so that current always flows through the first battery pack 11 and the second battery pack 12, regardless of whether the battery is in the first heating stage or the second heating stage. This helps to maintain the stability of the current flowing through the first battery pack 11 and the second battery pack 12. At the same time, it keeps the size of the circuit for heating the battery smaller, saving costs.

[0141] According to some embodiments of this application, the method further includes: in response to the battery temperature being lower than a preset temperature threshold, controlling the battery to be in a second heating stage to heat the battery via a switching circuit 101, the second heating stage including: repeatedly executing the steps of the second battery pack 12 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the first battery pack 11 N2 times via the switching circuit 101, wherein, in the battery heating state, the inductance satisfies the volt-second product balance.

[0142] The battery is controlled to alternate between a first heating stage and a second heating stage to heat the battery. In other words, the battery heating state includes putting the battery into a first heating stage and a second heating stage.

[0143] As described above, in the first heating stage and the second heating stage, the current flowing through the first energy storage circuit 102 flows in opposite directions, that is, the current flowing through the inductor flows in opposite directions. Therefore, in the battery heating state, the inductor satisfies the volt-second product balance, which means that in the consecutive first heating stage and second heating stage, the volt-second product of the inductor in the first heating stage is equal to the volt-second product in the second heating stage.

[0144] The volt-second product refers to the voltage applied across the inductor multiplied by the conduction time. The volt-second product of the inductor in the first heating stage is the voltage applied across the inductor during the first heating stage multiplied by the duration of the first heating stage, and the volt-second product of the inductor in the second heating stage is the voltage applied across the inductor during the second heating stage multiplied by the duration of the second heating stage.

[0145] The volt-second product can be used to characterize the amount of energy transferred through inductance. When the volt-second product is balanced, the energy transferred through inductance in the first heating stage is the same as the energy transferred through inductance in the second heating stage, thereby maintaining the energy balance between the first battery pack 11 and the second battery pack 12.

[0146] In the above technical solution, the volt-second product of the inductor in the first heating stage is equal to the volt-second product in the second heating stage. In this way, while achieving energy balance between the first battery pack 11 and the second battery pack 12, the duration of the first heating stage and the duration of the second heating stage can be controlled to be equal or unequal. It is also possible to control the current flowing through the inductor in the first heating stage and the current flowing through the inductor in the second heating stage to be equal or unequal, thus simplifying the control method of battery heating.

[0147] Referring to Figures 14 to 17, according to some embodiments of this application, the switching circuit 101 includes: a bridge arm 20, including an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm being connected to the positive terminal of the first battery pack 11, the lower bridge arm being connected to the negative terminal of the second battery pack 12, the negative terminal of the first battery pack 11 being connected to the positive terminal of the second battery pack 12, a first terminal of the first energy storage circuit 102 being connected between the upper bridge arm and the lower bridge arm, and a second terminal of the first energy storage circuit 102 being connected between the first battery pack 11 and the second battery pack 12.

[0148] Step 120 includes: performing the first step and the second step alternately in sequence.

[0149] The first step includes: controlling the upper arm to be on and the lower arm to be off.

[0150] The second step includes: controlling the lower bridge arm to be on and the upper bridge arm to be off.

[0151] The upper bridge arm includes an upper bridge arm switch V1, and the lower bridge arm includes a lower bridge arm switch V2. Turning the upper bridge arm switch V1 on / off enables the upper bridge arm to be turned on / off, and turning the lower bridge arm switch V2 on / off enables the lower bridge arm to be turned on / off. The types of the upper bridge arm switch V1 and the lower bridge arm switch V2 include, but are not limited to, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) or IGBTs (Insulated-Gate Bipolar Transistors). The upper and lower bridge arm switches can be the switching elements in the aforementioned switching circuit.

[0152] In step 120, the first step and the second step are executed alternately and repeatedly to bring the battery into a first heating stage. Specifically, the first step is executed to form a circuit between the first battery pack 11 and the first energy storage circuit 102 via the upper bridge arm, allowing the first battery pack 11 to charge the first energy storage circuit 102. The second step is executed to form a circuit between the second battery pack 12 and the first energy storage circuit 102 via the lower bridge arm, allowing the first energy storage circuit 102 to charge the second battery pack 12.

[0153] In some embodiments, the first energy storage circuit 102 is an inductor. As shown in FIG14, when the first step is performed, the upper bridge arm is turned on and the lower bridge arm is turned off. The first battery pack 11, the upper bridge arm, and the inductor form a loop. Current flows from the positive terminal of the first battery pack 11 through the upper bridge arm and the inductor, and then flows back to the negative terminal of the first battery pack 11. The inductor stores energy. The solid line with arrows in FIG14 shows the current path of the first battery pack 11 charging the inductor.

[0154] As shown in Figure 15, in the second step, the lower bridge arm is turned on and the upper bridge arm is turned off. The inductor, the lower bridge arm, and the second battery pack 12 form a circuit. Current flows from the inductor through the positive terminal, the negative terminal, and the lower bridge arm of the second battery pack 12, and then back to the inductor. In other words, the inductor releases energy to the second battery pack 12. The solid line with arrows in Figure 15 shows the current path of the inductor charging the second battery pack 12.

[0155] 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 first step to the second 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 second step to the first 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 significantly improves the problem of high-frequency whistling caused by excessive current flowing through the motor, maintaining more stable motor performance and improving battery heating efficiency.

[0156] In some embodiments, the number of bridge arms 20 can be multiple, and the multiple bridge arms 20 are connected in parallel. The first energy storage circuit 102 includes multiple first inductors L1 connected in parallel, and the multiple first inductors L1 are connected to the multiple bridge arms 20 one by one.

[0157] As shown in Figure 14, in the first step, the current flows out from the positive terminal of the first battery pack 11 and passes through each bridge arm 20 and the corresponding first inductor L1 to charge the first inductor L1.

[0158] As shown in Figure 15, the second step is performed, where each first inductor L1 releases energy to charge the second battery pack 12.

[0159] In some embodiments, the first energy storage circuit 102 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 first step, the first battery pack 11 charges the plurality of first inductors L1 and the second inductor L2. In the second step, the plurality of first inductors L1 and the second inductor L2 charge the second battery pack 12.

[0160] In some embodiments, a capacitor is also connected in parallel across the two ends of the battery.

[0161] As shown in Figure 14, in the first step, the upper bridge arm is turned on and the lower bridge arm is turned off. The capacitor forms a circuit with the second battery pack 12 through the upper bridge arm and the inductor to charge the second battery pack 12. The dashed line with arrows in Figure 14 shows the current path of the capacitor charging the second battery pack 12.

[0162] As shown in Figure 15, in the second step, the lower bridge arm is turned on and the upper bridge arm is turned off. The capacitor forms a circuit with the first battery pack 11 through the lower bridge arm and the inductor, so that the first battery pack 11 charges the inductor. The solid line with arrows in Figure 15 shows the current path of the first battery pack 11 charging the capacitor.

[0163] In the above technical solution, the energy transfer from the first battery pack 11 to the second battery pack 12 can be achieved by controlling the alternating conduction of the upper and lower bridge arms. The operation is simple and simplifies the control method of circuit heating.

[0164] According to some embodiments of this application, the method further includes step 130, which includes:

[0165] Perform the second step and the first step alternately in sequence.

[0166] In step 130, the second step and the first step are executed alternately and repeatedly to bring the battery into a second heating stage. Specifically, the second step is executed to form a circuit between the second battery pack 12 and the first energy storage circuit 102 via the lower bridge arm, allowing the second battery pack 12 to charge the first energy storage circuit 102. The first step is executed to form a circuit between the first battery pack 11 and the first energy storage circuit 102 via the upper bridge arm, allowing the first energy storage circuit 102 to charge the first battery pack 11.

[0167] In some embodiments, the first energy storage circuit 102 is an inductor. As shown in FIG16, when the second step is performed, the lower bridge arm is turned on and the upper bridge arm is turned off. The second battery pack 12, the lower bridge arm, and the inductor form a loop. Current flows from the positive terminal of the second battery pack 12 through the lower bridge arm and the inductor, and then flows back to the negative terminal of the second battery pack 12. The inductor stores energy. The solid line with arrows in FIG16 shows the current path of the second battery pack 12 charging the inductor.

[0168] As shown in Figure 17, in the first step, the upper bridge arm is turned on and the lower bridge arm is turned off. The first energy storage circuit 102, the upper bridge arm, and the first battery pack 11 form a loop. Current flows from the inductor through the positive terminal of the first battery pack 11, the negative terminal of the first battery pack 11, and the upper bridge arm, and then back to the inductor. That is, the inductor releases energy to the first battery pack 11. The solid line with arrows in Figure 17 shows the current path of the inductor charging the first battery pack 11.

[0169] A capacitor is also connected in parallel across the two ends of the battery.

[0170] As shown in Figure 16, in the second step, the lower bridge arm is turned on and the upper bridge arm is turned off. The capacitor forms a circuit with the first battery pack 11 through the lower bridge arm and the inductor to charge the first battery pack 11. The dashed line with arrows in Figure 16 shows the current path of the capacitor charging the first battery pack 11.

[0171] As shown in Figure 17, in the first step, the upper bridge arm is turned on and the lower bridge arm is turned off. The capacitor forms a circuit with the second battery pack 12 through the upper bridge arm and the inductor, so that the second battery pack 12 charges the inductor. The dashed line with arrows in Figure 17 shows the current path of the second battery pack 12 charging the capacitor.

[0172] In some embodiments, the battery heating method includes controlling the battery to alternately enter a first heating phase and a second heating phase, and the method may include:

[0173] The first and second steps are executed alternately and repeatedly to put the battery into the first heating stage. In the last step of the second stage, the inductor continuously releases energy to the second battery pack 12. At this time, the current flows from the inductor to the positive terminal of the second battery pack 12 until all the energy in the inductor is released and the current flowing through the inductor is 0. The second step remains unchanged, that is, the lower bridge arm remains on and the upper bridge arm remains off. Since the energy in the inductor has been released, the second battery pack 12 begins to charge the inductor. At this time, the current flows from the positive terminal of the second battery pack 12 to the inductor, and the current in the inductor begins to reverse, and the battery enters the second heating stage. After the inductor has stored all the energy, the first step is executed. The inductor, the first energy storage circuit 102, the upper bridge arm, and the first battery pack 11 form a loop. The current flows from the inductor through the positive terminal of the first battery pack 11 to charge the first battery pack 11. Thus, the transition from the first heating stage to the second heating stage is completed.

[0174] The method for transitioning from the second heating stage to the first heating stage is the same as the method for transitioning from the first heating stage to the second heating stage. The only difference is that in the last step of the second heating stage, after the inductor energy is released, the first step remains unchanged, causing the current to reverse, and the battery enters the first heating stage.

[0175] In some embodiments, the duration of the first heating phase and the second heating phase can be set according to different battery types and preset temperature threshold values. For example, the duration of the first heating phase and the second heating phase can be 1 second.

[0176] In some embodiments, the number of alternations between the first and second steps in the first heating phase, and the number of alternations between the first and second steps in the second heating phase, can be set according to different battery types and preset temperature thresholds, or can be set according to the duration of the first and second heating phases. After the first and second heating phases end, the temperatures of both the first battery pack 11 and the second battery pack 12 can be greater than or equal to the preset temperature threshold. For example, the number of alternations between the first and second steps in both the first and second heating phases can be 5 times.

[0177] In the above technical solution, the switching circuit 101 only needs to set the bridge arm 20, without setting other circuit structures, to control the battery to be in the second heating stage, realize the energy balance between the first battery pack 11 and the second battery pack 12, simplify the circuit structure and the method of controlling battery heating, and improve the reliability of the method of controlling battery heating.

[0178] Referring to Figure 2, this application embodiment provides a battery heating circuit, including: a switching circuit 101, a first terminal of which is connected to the positive terminal of the battery, and a second terminal of which is connected to the negative terminal of the battery, the battery including a first battery pack 11 and a second battery pack 12 connected in series; a first energy storage circuit 102, a first terminal of which is connected to the switching circuit 101, and a second terminal of which is connected to the midpoint between the first battery pack 11 and the second battery pack 12; and a controller configured to: acquire the temperature of the battery; and, in response to the battery temperature being lower than a preset temperature threshold, control the battery to be in a first heating stage to heat the battery via the switching circuit 101, wherein the first heating stage includes: repeatedly executing the steps of the first battery pack 11 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the second battery pack 12 N1 times via the switching circuit 101, wherein N1 is a positive integer greater than 1.

[0179] In other words, the controller can execute steps 110 and 120 above. The controller can store instructions in advance to execute the corresponding steps. The principle and method of controlling the battery to be in the first heating stage to heat the battery are described in the relevant description of the above embodiments, and will not be repeated below.

[0180] If the positive terminal of the first battery pack 11 can be connected to the negative terminal of the second battery pack 12, then the first terminal of the switch circuit 101 is connected to the positive terminal of the second battery pack 12, and the second terminal of the switch circuit 101 is connected to the negative terminal of the first battery pack 11.

[0181] The negative terminal of the first battery pack 11 can also be connected to the positive terminal of the second battery pack 12. Then, the first terminal of the switch circuit 101 is connected to the positive terminal of the first battery pack 11, and the second terminal of the switch circuit 101 is connected to the negative terminal of the second battery pack 12.

[0182] In some embodiments, temperature sensors may be used to detect the temperatures of the first battery pack 11 and the second battery pack 12. The controller receives the temperature information detected by the temperature sensors to determine whether to control the batteries to enter the first heating stage.

[0183] The controller may include, but is not limited to, the MCU (Microcontroller Unit) in the vehicle, or the controller in the BMS (Battery Management System) of the battery.

[0184] In some embodiments, the battery also includes a temperature sensor for detecting the temperature of the first battery pack 11 and the second battery pack 12. The temperature sensor is communicatively connected to the BMS, and the controller in the BMS can receive the temperature information of the first battery pack 11 and the second battery pack 12 detected by the temperature sensor, and control the battery to enter a first heating stage in response to the temperature of at least one of the first battery pack 11 and the second battery pack 12 being lower than a preset temperature threshold.

[0185] In some embodiments, the first energy storage circuit 102 may include, but is not limited to, an inductor.

[0186] In the above technical solution, the steps of charging the first battery pack 11 to the first energy storage circuit 102 and charging the second battery pack 12 by the first energy storage circuit 102 are repeated N1 times during the first heating stage. This enables the battery to self-heat without the need for external heating equipment, significantly reducing the cost of the battery heating circuit. Simultaneously, it also improves the energy transfer efficiency from the first battery pack to the second battery pack, thereby increasing the heating efficiency of the battery through the first energy storage circuit.

[0187] According to some embodiments of this application, the controller is also configured to: in response to the battery temperature being lower than a preset temperature threshold, control the battery to be in a second heating stage to heat the battery via the switching circuit 101, the second heating stage including: repeatedly executing the steps of the second battery pack 12 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the first battery pack 11 N2 times via the switching circuit 101, wherein N2 is a positive integer greater than 1.

[0188] In other words, the controller can execute the above step 130. The principle and method of controlling the battery to be in the second heating stage to heat the battery are described in the relevant description of the above embodiment, and will not be repeated below.

[0189] Understandably, the controller can be configured to alternately and repeatedly control the battery to be in a first heating state and a second heating state.

[0190] The above technical solution can realize energy exchange between the first battery pack 11 and the second battery pack 12, and maintain the energy balance between the first battery pack 11 and the second battery pack 12.

[0191] Referring to Figure 9, according to some embodiments of this application, the battery heating circuit further includes: a second energy storage circuit 103, a first terminal of the second energy storage circuit 103 connected to the positive terminal of the battery, a second terminal of the second energy storage circuit 103 connected to the negative terminal of the battery, and the controller is further configured to: in the first heating stage, through the switching circuit 101, repeatedly execute the steps of the first battery pack 11 charging the second energy storage circuit 103 and the second energy storage circuit 103 charging the second battery pack 12 N3 times, where N3 is a positive integer greater than 1.

[0192] The relevant principles and methods can be found in the descriptions of the above embodiments, and will not be repeated hereafter.

[0193] It is understood that when the battery heating circuit includes the second energy storage circuit 103, the controller can be configured to alternately repeat the following: the first battery pack 11 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the second battery pack 12, and alternately repeat the following: the first battery pack 11 charging the second energy storage circuit 103 and the second energy storage circuit 103 charging the second battery pack 12.

[0194] In some embodiments, the second energy storage circuit 103 may include, but is not limited to, a capacitor or an inductor.

[0195] In the above technical solution, the second energy storage circuit 103 can also realize the energy transfer from the first battery pack 11 to the second battery pack 12, further improving the heating efficiency of the battery.

[0196] According to some embodiments of this application, the controller is also configured to: during the first heating phase, simultaneously execute the first battery pack 11 charging the first energy storage circuit 102 and the second energy storage circuit 103 charging the second battery pack 12 via the switching circuit 101; and / or during the first heating phase, simultaneously execute the first energy storage circuit 102 charging the second battery pack 12 and the first battery pack 11 charging the second energy storage circuit 103 via the switching circuit 101.

[0197] The relevant principles and methods can be found in the descriptions of the above embodiments, and will not be repeated hereafter.

[0198] Therefore, during the first heating stage, current always flows through the first battery pack 11 and the second battery pack 12 through the first energy storage circuit 102 and the second energy storage circuit 103, which helps to maintain the stability of the current flowing through the first battery pack 11 and the second battery pack 12. This improves the heating efficiency of the batteries and makes the performance of the first battery pack 11 and the second battery pack 12 more stable.

[0199] Referring to Figure 9, according to some embodiments of this application, the battery heating circuit further includes: a second energy storage circuit 103, a first terminal of the second energy storage circuit 103 connected to the positive terminal of the battery, a second terminal of the second energy storage circuit 103 connected to the negative terminal of the battery, and the controller is further configured to: in the second heating stage, through the switching circuit 101, repeatedly execute the steps of the second battery pack 12 charging the second energy storage circuit 103 and the second energy storage circuit 103 charging the first battery pack 11 N4 times, where N4 is a positive integer greater than 1.

[0200] The relevant principles and methods can be found in the descriptions of the above embodiments, and will not be repeated hereafter.

[0201] It is understood that when the battery heating circuit includes the second energy storage circuit 103, the controller can be configured to alternately repeat the following: the second battery pack 12 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the first battery pack 11, and alternately repeat the following: the second battery pack 12 charging the second energy storage circuit 103 and the second energy storage circuit 103 charging the first battery pack 11.

[0202] The second energy storage circuit 103 can also realize the energy transfer from the second battery pack 12 to the first battery pack 11, further improving the heating efficiency of the battery.

[0203] According to some embodiments of this application, the controller is configured to: during the second heating phase, simultaneously execute the second battery pack 12 charging the first energy storage circuit 102 and the second energy storage circuit 103 charging the first battery pack 11 via the switching circuit 101; and / or during the second heating phase, simultaneously execute the first energy storage circuit 102 charging the first battery pack 11 and the second battery pack 12 charging the second energy storage circuit 103 via the switching circuit 101.

[0204] The relevant principles and methods can be found in the descriptions of the above embodiments, and will not be repeated hereafter.

[0205] In the above technical solution, during the second heating stage, the first energy storage circuit 102 and the second energy storage circuit 103 ensure that current always flows through the first battery pack 11 and the second battery pack 12. This helps to maintain the stability of the current flowing through the first battery pack 11 and the second battery pack 12, thereby improving the heating efficiency of the battery and maintaining the energy balance of the first battery pack 11 and the second battery pack 12, while also making the performance of the first battery pack 11 and the battery pack more stable.

[0206] Referring to Figures 10 to 14, according to some embodiments of this application, the first energy storage circuit 102 includes at least one inductor, and the second energy storage circuit 103 includes a capacitor.

[0207] In some embodiments, the first energy storage circuit 102 may include an inductor.

[0208] In other embodiments, the first energy storage circuit 102 may also include multiple inductors, which may be connected in parallel or in series, or some of the multiple inductors may be connected in parallel and then connected in series with the remaining inductors.

[0209] The principles and methods of using inductors and capacitors to put the battery into the first and second heating stages can be found in the above descriptions, and will not be repeated below.

[0210] In the above technical solution, the inductor can store a larger amount of electricity, which can improve the energy transfer efficiency from the first battery pack 11 to the second battery pack 12, thereby improving the heating efficiency of the battery. Compared with the inductor, the capacitor is smaller in size and can achieve rapid charging and discharging, so that current always flows through the first battery pack 11 and the second battery pack 12, regardless of whether the battery is in the first heating stage or the second heating stage. This helps to maintain the stability of the current flowing through the first battery pack 11 and the second battery pack 12. At the same time, it keeps the size of the circuit for heating the battery smaller, saving costs.

[0211] Referring to Figures 14 to 17, according to some embodiments of this application, the switching circuit 101 includes: a bridge arm 20, including an upper bridge arm and a lower bridge arm connected in series, the upper bridge arm being connected to the positive terminal of the first battery pack 11, the lower bridge arm being connected to the negative terminal of the second battery pack 12, the negative terminal of the first battery pack 11 being connected to the positive terminal of the second battery pack 12, wherein a first terminal of the first energy storage circuit 102 is connected between the upper bridge arm and the lower bridge arm, and a second terminal of the first energy storage circuit 102 is electrically connected between the first battery pack 11 and the second battery pack 12, and the controller is configured to: sequentially and alternately execute a first step and a second step to control the battery to be in a first heating stage; wherein the first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off, and the second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off.

[0212] The structure of the bridge arm 20, and the method of sequentially and alternately performing the first step and the second step through the bridge arm 20 to put the battery into the first heating stage, can be referred to the relevant description of the above embodiments, and will not be repeated below.

[0213] The switching on / off of the upper and lower bridge arms in the bridge arm 20 can be executed by a controller. The controller can execute the switching on / off sequence of the upper and lower bridge arms as described in the above embodiments, so that the battery is in the first heating stage.

[0214] As shown in Figures 14 to 17, the battery heating circuit also includes a first switch K1 and a second switch K2. The first end of the first switch K1 is connected to the positive terminal of the battery, and the second end of the first switch K1 is connected to the upper bridge arm, used to control the connection / disconnection between the positive terminal of the battery and the upper bridge arm. The first end of the second switch K2 is connected to the negative terminal of the battery, and the second end of the second switch K2 is connected to the lower bridge arm, used to control the connection / disconnection between the negative terminal of the battery and the lower bridge arm. Thus, when the battery needs to be heated, the first switch K1 and the second switch K2 can control the connection between the battery and the bridge arm 20; when the battery does not need to be heated, the first switch K1 and the second switch K2 can control the disconnection between the battery and the bridge arm 20, thereby not affecting the normal performance of the battery.

[0215] In some embodiments, the first switch K1 can be connected to the upper bridge arm via the first connector 24, and the second switch K2 can be connected to the lower bridge arm via the second connector 25.

[0216] In some embodiments, the battery heating circuit further includes a third switch K3 connected in parallel with the second switch K2 and a first resistor R1. The third switch and the first resistor are connected in series to provide current limiting protection.

[0217] In some embodiments, the battery heating circuit further includes a current sensor 23, which is connected between the battery and the switching circuit 101. For example, it can be connected between the positive terminal of the battery and the first switch to detect the current output by the battery, so as to regulate the current used for battery heating in the battery heating circuit to produce a better heating effect on the battery.

[0218] In some embodiments, the first switch K1, the second switch K2, and the third switch K3 may include, but are not limited to, relays.

[0219] In the above technical solution, by setting the bridge arm 20, the circuit structure is relatively simple, and the control of the circuit can be simplified, thereby improving the reliability of the method of heating the battery through the battery heating circuit.

[0220] According to some embodiments of this application, the controller is also configured to control the battery to be in a second heating stage to heat the battery via the switching circuit 101, wherein the controller is configured to sequentially and alternately execute the second step and the first step to control the battery to be in the second heating stage.

[0221] The method of sequentially and alternately performing the second step and the first step by the bridge arm 20 to put the battery into the second heating stage can be referred to the relevant description of the above embodiment, and will not be repeated below.

[0222] The switching on / off of the upper and lower bridge arms in the bridge arm 20 can be executed by a controller. The controller can execute the switching on / off sequence of the upper and lower bridge arms as described in the above embodiments, so that the battery is in the second heating stage.

[0223] In the above technical solution, the switching circuit 101 only needs to set the bridge arm 20, without setting other circuit structures, to control the battery in the second heating stage, realize the energy balance between the first battery pack 11 and the second battery pack 12, and simplify the circuit structure and control method.

[0224] Referring to Figure 18, according to some embodiments of this application, the circuit further includes: multiple neutral lines 30 connected in parallel, the first end of the neutral line 30 being connected to the second end of the first energy storage circuit 102, and the second end of the neutral line 30 being connected between the first battery pack 11 and the second battery pack 12.

[0225] In other words, the second end of the first energy storage circuit 102 is connected to the midpoint between the first battery pack 11 and the second battery pack 12 via the neutral line 30.

[0226] During the first heating stage, in the first step, current flows from the positive terminal of the first battery pack 11 through the upper bridge arm and the inductor, and then flows back to the negative terminal of the first battery pack 11 through multiple parallel neutral lines 30, whereby the inductor stores energy. In the second step, current flows out of the inductor and into the positive terminal of the second battery pack 12 through multiple parallel neutral lines 30, meaning the inductor releases energy to the second battery pack 12.

[0227] During the second heating stage, in the second step, current flows from the positive terminal of the second battery pack 12 through the upper bridge arm and the inductor, and then flows back to the negative terminal of the second battery pack 12 through multiple parallel neutral lines 30, where the inductor stores energy. During the first step, current flows out of the inductor and into the positive terminal of the first battery pack 11 through multiple parallel neutral lines 30, meaning the inductor releases energy to the first battery pack 11.

[0228] As can be seen from the above, in both the first and second heating stages, the current can pass through multiple neutral lines 30 to achieve energy transfer between the first battery pack 11 and the second battery pack 12.

[0229] Understandably, due to the limited load of a single neutral line 30, the current flowing through the single neutral line 30 is limited, and the current flowing through the first battery pack 11 or the second battery pack 12 is also limited, resulting in low heating efficiency of the first battery pack 11 and the second battery pack 12.

[0230] With multiple neutral lines 30 connected in parallel, since the current can be diverted from multiple neutral lines 30, the current flowing through each neutral line 30 is relatively small. Therefore, there is no need to consider the load limitation of the neutral line 30. Thus, the current in the circuit can be appropriately increased, so that the current flowing through the first battery pack 11 or the second battery pack 12 is increased accordingly, thereby improving the heating efficiency of the first battery pack 11 and the second battery pack 12.

[0231] In some embodiments, the circuit further includes a fourth switch V3, which is disposed on the neutral line 30 and used to control the on / off state of the neutral line 30. The fourth switch V3 may include, but is not limited to, any one of a MOSFET or an IGBT.

[0232] In the above technical solution, the current is transmitted through multiple neutral lines 30, thereby increasing the current flowing through the first energy storage circuit 102, improving the efficiency of energy transfer between the first battery pack 11 and the second battery pack 12 through the first energy storage circuit 102, and further improving the heating efficiency of the battery.

[0233] According to some embodiments of this application, there are multiple bridge arms 20 connected in parallel. The first energy storage circuit 102 includes multiple first inductors L1 connected in parallel, and the multiple first inductors L1 are connected to the multiple bridge arms 20 one by one.

[0234] The structure of each bridge arm 20 is the same as that of the bridge arm 20 described in the above embodiments.

[0235] Multiple parallel-connected first inductors L1 can be inductors in the motor, such as three-phase inductors in the motor. Multiple bridge arms 20 can be three-phase bridge arms. In this way, when heating the vehicle's battery, the existing motor in the vehicle can be used to heat the battery, reducing costs and keeping the vehicle's weight relatively low.

[0236] The method of charging the first battery pack 11 to the multiple first inductors L1 through the multiple bridge arms 20, and charging the second battery pack 12 through the multiple first inductors L1 through the multiple bridge arms 20, can be referred to the relevant description in the above embodiments, and will not be repeated below.

[0237] In the above technical solution, energy transfer between the first battery pack 11 and the second battery pack 12 can be achieved through multiple first inductors L1, and the multiple first inductors L1 are connected in parallel, which can suppress high-frequency noise in the circuit, make the circuit current more stable, and further enhance the heating efficiency of the battery.

[0238] According to some embodiments of this application, the first energy storage circuit 102 further includes a second inductor L2, which is connected in series with a plurality of first inductors L1 connected in parallel.

[0239] The first end of the second inductor L2 is connected to the multiple first inductors L1 connected in parallel, and the second end of the second inductor L2 is connected to the midpoint between the first battery pack 11 and the second battery pack 12.

[0240] Multiple first inductors L1 and second inductors L2 can all be inductors in the same motor.

[0241] In the above technical solution, by connecting the second inductor L2 in series, the energy stored in the first energy storage circuit 102 can be increased, and the energy transfer efficiency between the first battery pack 11 and the second battery pack 12 can be improved, so as to further enhance the heating efficiency of the battery.

[0242] This application provides a battery system that includes the battery heating circuit described in the above embodiments.

[0243] The battery system includes a battery connected to a battery heating circuit. The battery system has the beneficial effects of the battery heating circuit provided in the embodiments of this application; for details, please refer to the specific descriptions of the battery heating circuit in the above embodiments, which will not be repeated here.

[0244] This application provides an electrical device that includes the battery system described in the above embodiments, the battery system being used to provide electrical energy.

[0245] The electrical devices can be referred to the relevant descriptions in the above embodiments, and will not be repeated below.

[0246] Referring to Figures 14 to 17, this application embodiment provides a battery heating method. The battery includes a first battery pack 11 and a second battery pack 12 connected in series. A battery connecting arm 20 is provided, which includes an upper arm and a lower arm connected in series. The upper arm is connected to the positive terminal of the first battery pack 11, and the lower arm is connected to the negative terminal of the second battery pack 12. The negative terminal of the first battery pack 11 is connected to the positive terminal of the second battery pack 12. A first terminal of a first energy storage circuit 102 is connected between the upper and lower arms, and a second terminal of the first energy storage circuit 102 is connected between the first battery pack 11 and the second battery pack 12. The method includes:

[0247] Obtain the battery temperature;

[0248] In response to the battery temperature being lower than a preset temperature threshold, the bridge arm 20 controls the battery to alternately enter a first heating stage and a second heating stage to heat the battery. The first heating stage includes: repeatedly executing N1 times via the switching circuit 101 the steps of the first battery pack 11 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the second battery pack 12. The second heating stage includes: repeatedly executing N2 times via the switching circuit 101 the steps of the second battery pack 12 charging the first energy storage circuit 102 and the first energy storage circuit 102 charging the first battery pack 11.

[0249] The process of controlling the battery to be in the first heating stage via the bridge arm 20 includes: sequentially and alternately executing the first step and the second step; the first step includes: controlling the upper bridge arm to be on and the lower bridge arm to be off, and the second step includes: controlling the lower bridge arm to be on and the upper bridge arm to be off.

[0250] Controlling the battery to be in the second heating stage via the bridge arm 20 includes: sequentially and alternately performing the second step and the first step.

[0251] The number of bridge arms 20 is three, and the three bridge arms 20 are connected in parallel. The first energy storage circuit 102 includes three first inductors L1 connected in parallel, and the three first inductors L1 are connected one-to-one with the three bridge arms 20. The first energy storage circuit 102 also includes a second inductor L2, which is connected in series with the three first inductors L1 connected in parallel.

[0252] A capacitor is also connected in parallel across the two ends of the battery. The first heating stage further includes: performing a first step to simultaneously charge the first battery pack 11 for the first energy storage circuit 102 and the capacitor for the second battery pack 12; and performing a second step to simultaneously charge the first energy storage circuit 102 for the second battery pack 12 and the first battery pack 11 for the capacitor.

[0253] The second heating stage further includes: performing a second step to simultaneously charge the first energy storage circuit 102 with the second battery pack 12 and charge the first battery pack 11 with the capacitor; and performing a first step to simultaneously charge the first battery pack 11 with the first energy storage circuit 102 and charge the capacitor with the second battery pack 12.

[0254] The method also includes: when the battery is heated, the inductor satisfies the volt-second product balance.

[0255] 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 first battery pack and a second battery pack connected in series, the positive terminal of the battery being connected to a first terminal of a switching circuit, the negative terminal of the battery being connected to a second terminal of the switching circuit, the switching circuit also being connected to a first terminal of the first energy storage circuit, the second terminal of the first energy storage circuit being connected to the midpoint between the first battery pack and the second battery pack, the method comprising: Obtain the temperature of the battery; In response to the battery temperature being lower than a preset temperature threshold, the switching circuit controls the battery to enter a first heating stage to heat the battery, wherein... The first heating stage includes: repeatedly performing the steps of the first battery pack charging the first energy storage circuit and the first energy storage circuit charging the second battery pack N1 times through the switching circuit, where N1 is a positive integer greater than 1.

2. The battery heating method according to claim 1, wherein, The method further includes: in response to the battery temperature being lower than the preset temperature threshold, controlling the battery to enter a second heating stage to heat the battery via the switching circuit. The second heating stage includes: repeatedly performing the steps of the second battery pack charging the first energy storage circuit and the first energy storage circuit charging the first battery pack N2 times through the switching circuit, where N2 is a positive integer greater than 1.

3. The battery heating method according to claim 1, wherein, 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 the battery, and the second end of the second energy storage circuit is connected to the negative terminal of the battery. The first heating stage further includes: repeatedly performing the steps of the first battery pack charging the second energy storage circuit and the second energy storage circuit charging the second battery pack N3 times through the switching circuit, where N3 is a positive integer greater than 1.

4. The battery heating method according to claim 3, wherein, The first heating stage also includes: The switching circuit simultaneously performs the charging of the first energy storage circuit by the first battery pack and the charging of the second battery pack by the second energy storage circuit; and / or The switching circuit simultaneously performs the functions of the first energy storage circuit charging the second battery pack and the first battery pack charging the second energy storage circuit.

5. The battery heating method according to claim 2, wherein, A second energy storage circuit is connected in parallel across the two ends of the battery, wherein a first end of the second energy storage circuit is connected to the positive terminal of the battery, and a second end of the second energy storage circuit is connected to the negative terminal of the battery; the second heating stage further includes: The switching circuit repeats the steps of the second battery pack charging the second energy storage circuit and the second energy storage circuit charging the first battery pack N4 times, where N4 is a positive integer greater than 1.

6. The battery heating method according to claim 5, wherein, The second heating stage also includes: The switching circuit simultaneously performs the charging of the first energy storage circuit by the second battery pack and the charging of the first battery pack by the second energy storage circuit; and / or The switching circuit simultaneously performs the first energy storage circuit to charge the first battery pack and the second battery pack to charge the second energy storage circuit.

7. The battery heating method according to any one of claims 3-6, wherein, The first energy storage circuit includes at least one inductor, and the second energy storage circuit includes a capacitor.

8. The battery heating method according to claim 7, wherein, The method further includes: in response to the battery temperature being lower than the preset temperature threshold, controlling the battery to enter a second heating stage to heat the battery via the switching circuit, wherein the second heating stage includes: repeatedly executing the steps of the second battery pack charging the first energy storage circuit and the first energy storage circuit charging the first battery pack N2 times via the switching circuit, wherein... When the battery is heated, the inductor satisfies the volt-second product balance.

9. The battery heating method according to any one of claims 1-8, 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 is connected to the positive terminal of the first battery pack; the lower bridge arm is connected to the negative terminal of the second battery pack; the negative terminal of the first battery pack is connected to the positive terminal of the second battery pack; a first terminal of the first energy storage circuit is connected between the upper and lower bridge arms; and a second terminal of the first energy storage circuit is connected between the first battery pack and the second battery pack. The step of repeatedly charging the first energy storage circuit with the first battery pack and charging the second battery pack with the first energy storage circuit N1 times through the switching circuit includes: sequentially and alternately performing the first step and the second step. The first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off. The second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off.

10. The battery heating method according to claim 9, wherein, The method further includes, when the battery is controlled to be in a second heating stage to heat the battery via the switching circuit, the step of repeatedly performing the second battery pack charging the first energy storage circuit and the first energy storage circuit charging the first battery pack N2 times via the switching circuit includes: sequentially and alternately performing the second step and the first step.

11. A battery heating circuit, wherein, include: A switching circuit, wherein a first terminal of the switching circuit is connected to the positive terminal of the battery and a second terminal is connected to the negative terminal of the battery, and the battery includes a first battery pack and a second battery pack connected in series. A first energy storage circuit, wherein a first end of the first energy storage circuit is connected to the switching circuit, and a second end is connected to the midpoint between the first battery pack and the second battery pack; The controller is configured as follows: Obtain the temperature of the battery; In response to the battery temperature being lower than a preset temperature threshold, the switching circuit controls the battery to enter a first heating stage to heat the battery, wherein... The first heating stage includes: repeatedly performing the steps of the first battery pack charging the first energy storage circuit and the first energy storage circuit charging the second battery pack N1 times through the switching circuit, where N1 is a positive integer greater than 1.

12. The battery heating circuit according to claim 11, wherein, The controller is also configured to: in response to the battery temperature being lower than the preset temperature threshold, control the battery to enter a second heating stage to heat the battery via the switching circuit. The second heating stage includes: repeatedly performing the steps of the second battery pack charging the first energy storage circuit and the first energy storage circuit charging the first battery pack N2 times through the switching circuit, where N2 is a positive integer greater than 1.

13. The battery heating circuit according to claim 11, wherein, The battery heating circuit also includes: A second energy storage circuit, wherein a first terminal of the second energy storage circuit is connected to the positive terminal of the battery, and a second terminal of the second energy storage circuit is connected to the negative terminal of the battery, and the controller is further configured to: During the first heating stage, the switching circuit repeats the steps of the first battery pack charging the second energy storage circuit and the second energy storage circuit charging the second battery pack N3 times, where N3 is a positive integer greater than 1.

14. The battery heating circuit according to claim 13, wherein, The controller is also configured to: During the first heating phase, the switching circuit simultaneously performs the charging of the first energy storage circuit by the first battery pack and the charging of the second battery pack by the second energy storage circuit; and / or During the first heating phase, the switching circuit simultaneously performs the charging of the second battery pack by the first energy storage circuit and the charging of the second energy storage circuit by the first battery pack.

15. The battery heating circuit according to claim 12, wherein, The battery heating circuit also includes: A second energy storage circuit, wherein a first terminal of the second energy storage circuit is connected to the positive terminal of the battery, and a second terminal of the second energy storage circuit is connected to the negative terminal of the battery, and the controller is further configured to: During the second heating stage, the switching circuit repeats the steps of the second battery pack charging the second energy storage circuit and the second energy storage circuit charging the first battery pack N4 times, where N4 is a positive integer greater than 1.

16. The battery heating circuit according to claim 15, wherein, The controller is configured to: During the second heating phase, the switching circuit simultaneously performs the charging of the first energy storage circuit by the second battery pack and the charging of the first battery pack by the second energy storage circuit; and / or During the second heating phase, the switching circuit simultaneously performs the first energy storage circuit to charge the first battery pack and the second battery pack to charge the second energy storage circuit.

17. The battery heating circuit according to any one of claims 13-16, wherein, The first energy storage circuit includes at least one inductor, and the second energy storage circuit includes a capacitor.

18. The battery heating circuit according to any one of claims 11-17, wherein, The switching circuit includes: The bridge arm includes an upper bridge arm and a lower bridge arm connected in series. The upper bridge arm is connected to the positive terminal of the first battery pack, and the lower bridge arm is connected to the negative terminal of the second battery pack. The negative terminal of the first battery pack is connected to the positive terminal of the second battery pack. A first terminal of the first energy storage circuit is connected between the upper bridge arm and the lower bridge arm, and a second terminal of the first energy storage circuit is electrically connected between the first battery pack and the second battery pack. The controller is configured to execute the first step and the second step alternately in sequence to control the battery in the first heating stage; in, The first step includes: controlling the upper bridge arm to be turned on and the lower bridge arm to be turned off. The second step includes: controlling the lower bridge arm to be turned on and the upper bridge arm to be turned off.

19. The battery heating circuit according to claim 18, wherein, The controller is further configured such that, when the battery is controlled to be in a second heating stage to heat the battery via the switching circuit, the controller is configured to: The second step and the first step are performed alternately in sequence to control the battery to be in the second heating stage.

20. The battery heating circuit according to claim 18, wherein, The circuit further includes: multiple parallel neutral lines, the first end of which is connected to the second end of the first energy storage circuit, and the second end of which is connected between the first battery pack and the second battery pack.

21. The battery heating circuit according to claim 18, wherein, The bridge arms are multiple, and the multiple bridge arms are connected in parallel. The first energy storage circuit includes: Multiple first inductors are connected in parallel, and each of the multiple first inductors is connected to a corresponding bridge arm.

22. The battery heating circuit according to claim 21, wherein, The first energy storage circuit further includes a second inductor, which is connected in series with a plurality of the first inductors that are connected in parallel.

23. A battery system, wherein, Includes the battery heating circuit according to any one of claims 11-22.

24. An electrical appliance, wherein, Includes the battery system according to claim 23, wherein the battery system supplies power to the electrical device.

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