Battery heating circuit, control method and controller, battery system, electric device

Abstract

The application discloses a battery heating circuit, a control method and a controller, a battery system and a power consumption device. The battery heating circuit comprises a battery, a resonance capacitor and a bridge arm. The battery has a battery inductance. The resonance capacitor is connected in parallel with the battery to form an LC parallel resonance circuit with the battery inductance. The bridge arm is connected in parallel with the battery. The bridge arm comprises a first bridge arm switch tube and a second bridge arm switch tube connected in series.

Description

Technical Field

[0001] This application relates to the field of electrical engineering, and more specifically to a battery heating circuit, control method and controller, battery system, and electrical equipment. Background Technology

[0002] Currently, vehicles typically incorporate self-heating devices to raise the battery temperature when it gets too low. However, these self-heating devices suffer from high energy consumption. Summary of the Invention

[0003] This application is made to address at least one of the aforementioned problems. According to a first aspect of this application, a battery heating circuit is provided, comprising: a battery, a resonant capacitor, and a bridge arm; wherein the battery has a battery inductance; the resonant capacitor is connected in parallel with the battery to form an LC parallel resonant circuit with the battery inductance; the bridge arm is connected in parallel with the battery; the bridge arm includes a first bridge arm switch and a second bridge arm switch connected in series.

[0004] In one embodiment of this application, the battery heating circuit further includes a current limiting device, which is connected in parallel with the first bridge arm switch and in series with the second bridge arm switch.

[0005] In one embodiment of this application, the current limiting device includes at least one of a current limiting resistor, a current limiting inductor, and a current limiting capacitor.

[0006] In one embodiment of this application, the current limiting device includes a current limiting inductor and a current limiting capacitor connected in series.

[0007] In one embodiment of this application, the battery heating circuit further includes a switching device for controlling the conduction and cutoff between the current limiting device and the bridge arm.

[0008] In one embodiment of this application, the switching device includes: a first switch electrically connected between the current limiting device and the midpoint of the bridge arm; or / and a second switch electrically connected between the current limiting device and the busbar of the bridge arm; or / and a third switch, wherein the current limiting device consists of at least two devices connected in series, and the third switch is electrically connected between any two adjacent devices.

[0009] In one embodiment of this application, the bridge arm is a bridge arm of an inverter, a power factor correction circuit, or a DC-DC converter.

[0010] According to a second aspect of this application, a heating control method is also provided, the heating control method being based on any of the battery heating circuits described above, the heating control method comprising: controlling the first bridge arm switch and the second bridge arm switch to alternately turn on and off, generating the resonant current in the LC parallel resonant circuit, so as to heat the battery through the internal resistance of the battery.

[0011] In one embodiment of this application, controlling the first bridge arm switch and the second bridge arm switch to alternately turn on and off to generate the resonant current in the LC parallel resonant circuit includes: determining a target resonant current; generating a PWM wave control signal based at least on the target resonant current; and controlling the first bridge arm switch and the second bridge arm switch to alternately turn on and off based on the PWM wave control signal to generate the target resonant current in the LC parallel resonant circuit.

[0012] In one embodiment of this application, generating a PWM wave control signal based at least on the target resonant current includes: determining the frequency and / or duty cycle of the PWM wave control signal based at least on the target resonant current.

[0013] In one embodiment of this application, generating a PWM wave control signal based at least on the target resonant current includes: determining the frequency of the PWM wave control signal based on the resonant frequency of the LC parallel resonant circuit; and determining the duty cycle of the PWM wave control signal based on the target resonant current.

[0014] In one embodiment of this application, determining the frequency of the PWM wave control signal based on the resonant frequency of the LC parallel resonant circuit includes: using the resonant frequency of the LC parallel resonant circuit as the frequency of the PWM wave control signal.

[0015] In one embodiment of this application, the battery heating circuit further includes: a current limiting device and a switching device, the switching device being used to control the conduction and cutoff between the current limiting device and the bridge arm; the heating control method further includes: when the temperature of the battery is lower than a first temperature threshold, controlling the current limiting device to conduct with the bridge arm through the switching device, and controlling the bridge arm to generate a resonant current in the LC parallel resonant circuit; when the temperature of the battery is higher than a second temperature threshold, controlling the current limiting device to cut off with the bridge arm through the switching device, and controlling at least one of the first bridge arm switching transistor and the second bridge arm switching transistor to cut off; wherein, the second temperature threshold is greater than the first temperature threshold.

[0016] According to a third aspect of this application, a controller is also provided, the controller comprising: a storage medium and a processor, the storage medium storing a computer program executed by the processor, the computer program, when executed by the processor, causing the processor to perform any of the heating control methods described above.

[0017] According to a fourth aspect of this application, a battery system is also provided, the battery system comprising: any of the battery heating circuits described above, or any of the controllers described above.

[0018] According to a fifth aspect of this application, an electrical device is also provided, the electrical device comprising: any of the above-described battery heating circuits, any of the above-described controllers, or any of the above-described battery systems.

[0019] According to the battery heating circuit, control method, controller, battery system, and electrical equipment provided in the embodiments of this application, a self-heating circuit for the battery is composed of a battery inductor, a resonant capacitor, bridge arms, and a current-limiting device. An LC parallel resonant circuit is formed by the battery inductor and the resonant capacitor, and a resonant current is generated in the LC parallel resonant circuit through the first and second bridge arm switches to heat the battery through its internal resistance. The resonant circuit has low impedance and low energy consumption. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a circuit topology diagram of a battery heating circuit according to an embodiment of the present invention;

[0022] Figure 2 This is a circuit topology diagram of a battery heating circuit shown in another embodiment of the present invention;

[0023] Figure 3 This is a circuit topology diagram of a battery heating circuit shown in another embodiment of the present invention;

[0024] Figure 4 The waveforms of the battery's output current, resonant current, and discharge current are shown in an embodiment of the present invention.

[0025] Figure 5 This is a flowchart illustrating a heating control method according to an embodiment of the present invention;

[0026] Figure 6This is a schematic block diagram of a controller according to an embodiment of the present invention; Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the present invention more apparent, exemplary embodiments according to the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely a part of the embodiments of the present invention, and not all of the embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein. Based on the embodiments of the present invention described herein, all other embodiments obtained by those skilled in the art without inventive effort should fall within the protection scope of the present invention.

[0028] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0029] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0030] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “compose” and / or “comprising,” when used in this specification, confirm the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0031] Currently, battery self-heating is mainly achieved through a battery self-heating circuit. This self-heating is primarily achieved through the cyclic discharge of the battery. Related technology one involves setting up a bridge arm converter, windings, and energy storage elements, using the bridge arm converter to cyclically charge and discharge the battery and the energy storage elements to heat the battery. Related technology two involves setting up a heating circuit and an energy storage module, controlling the cyclic charging and discharging of the battery pack and the energy storage module through the heating circuit, generating alternating current that heats the battery pack's internal resistance. Related technology three involves setting up a capacitor unit and a winding inductor assembly, placing the winding inductor assembly and the capacitor unit in a resonant state to heat the battery pack. Related technology four involves using a motor and a resonant capacitor to self-heat the battery. However, the aforementioned technologies require numerous components, have long battery charging and discharging circuits with high impedance, and low heating efficiency. To address at least some of the problems described above, this application proposes the following embodiments.

[0032] To fully understand this invention, a detailed structure will be presented in the following description to illustrate the technical solution proposed by this invention. Optional embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0033] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] First, let me introduce the application scenario of the battery heating circuit illustrated in this application. This battery heating circuit is used in the self-heating process of the battery.

[0035] refer to Figure 1 This application provides a battery heating circuit, which includes: a battery, a resonant capacitor, and a current limiting device; wherein, the battery has a battery inductance; the resonant capacitor is connected in parallel with the battery so that the resonant capacitor and the battery inductance form an LC parallel resonant circuit; a bridge arm is connected in parallel with the battery; the bridge arm includes a first bridge arm switch and a second bridge arm switch connected in series.

[0036] In the above scheme, a self-heating circuit for the battery is formed using a battery inductor, a resonant capacitor, bridge arms, and current-limiting devices. The battery inductor and resonant capacitor form an LC parallel resonant circuit, and a resonant current is generated in the LC parallel resonant circuit through the first and second bridge arm switches, which heats the battery through its internal resistance. The resonant circuit has few components, a simple structure, low impedance, and low energy consumption. The following section provides a detailed description of each structure with reference to the accompanying drawings.

[0037] When setting up a battery, any battery device with energy storage function can be used. For example, the battery can be a battery in an electrical device. For example, the electrical device can be a vehicle, in which case, the battery can be the vehicle's power battery; of course, the battery can also be a vehicle's storage battery. For example, the battery can be a cell group composed of multiple cells connected in series or parallel. For example, the battery can be a vehicle's battery pack. Of course, the battery's inductance value is not zero; that is, the battery has its own inductance and functions as an inductor, meaning the battery inductance is similar to the battery's equivalent inductance. In application, the battery's inductance value can be measured in advance, i.e., the battery inductance value is measured. For example, the battery's own inductance value is L1.

[0038] When setting the resonant capacitor, refer to Figures 1-3 In this context, C1 represents the resonant capacitor, which can be any capacitor component. For example, a resonant capacitor can consist of a single capacitor unit. Alternatively, a resonant capacitor can be composed of multiple capacitor units connected in parallel and / or in series.

[0039] Furthermore, the resonant capacitor is connected in parallel with the battery, so that the resonant capacitor and the battery inductance form an LC parallel resonant circuit. Specifically, the first terminal of the resonant capacitor is electrically connected to the positive terminal of the battery, and the second terminal of the resonant capacitor is electrically connected to the negative terminal of the battery, thereby connecting the resonant capacitor and the battery in parallel to form an LC parallel resonant circuit.

[0040] When setting up the bridge arm, refer to Figures 1-3 The bridge arm includes a first bridge arm switch and a second bridge arm switch connected in series, and the bridge arm is connected in parallel with the battery. It should be explained that a bridge arm refers to a bridge arm circuit formed by two switches connected in series, one of which is the upper bridge arm switch, and the other is the lower bridge arm switch. Correspondingly, the bridge arm has a midpoint, which refers to the series connection point between the upper and lower bridge arm switches. The first and second bridge arm switches can be the upper and lower bridge arm switches, respectively. (Reference) Figures 1-3 The first bridge arm switch is the lower bridge arm switch, and the second bridge arm switch is the upper bridge arm switch. Alternatively, in other embodiments, the first bridge arm switch can be the upper bridge arm switch, and the second bridge arm switch can be the lower bridge arm switch. When the bridge arm and battery are connected in parallel, the positive bus of the bridge arm is electrically connected to the positive terminal of the battery, and the negative bus of the bridge arm is electrically connected to the negative terminal of the battery, thus achieving parallel connection between the bridge arm and the battery.

[0041] For example, refer to Figures 1-3The first bridge arm switch can be electrically connected between the midpoint of the bridge arm and the negative busbar of the bridge arm, and the second bridge arm switch can be electrically connected between the midpoint of the bridge arm and the positive busbar of the bridge arm. Alternatively, in other embodiments, the first bridge arm switch can be electrically connected between the midpoint of the bridge arm and the positive busbar of the bridge arm, and the second bridge arm switch can be electrically connected between the midpoint of the bridge arm and the negative busbar of the bridge arm.

[0042] In the above embodiments, a self-heating circuit for the battery is composed of a battery inductor, a resonant capacitor, bridge arms, and current-limiting devices. An LC parallel resonant circuit is formed using the battery inductor and the resonant capacitor. A resonant current is generated in the LC parallel resonant circuit through the first and second bridge arm switches, heating the battery through its internal resistance. Compared to related technologies, this application uses the battery's own inductance as part of the resonant circuit, eliminating the need for a separate resonant inductor. This results in fewer components, a simpler structure, lower impedance, and lower energy consumption in the resonant circuit.

[0043] In some embodiments, the battery heating circuit may further include a current-limiting device, which is connected in parallel with the first bridge arm switch and in series with the second bridge arm switch. The current-limiting device provides current-limiting protection for the bridge arm switches, preventing overload.

[0044] When setting up a current-limiting device, any device with current-limiting functionality can be used to form the current-limiting device. (Reference) Figure 1 The current-limiting device is connected in parallel with the first bridge arm switch and in series with the second bridge arm switch. That is, the current-limiting device can be connected in parallel with one of the bridge arm switches and in series with the other, thereby limiting the discharge current in the bridge arm and providing current-limiting protection for the bridge arm switch to prevent overload. Specifically, the current-limiting device is connected in parallel with the first bridge arm switch and in series with the second bridge arm switch, so that when the second bridge arm switch is turned on, the current-limiting device can limit the current flowing through the second bridge arm switch, preventing overload of the second bridge arm switch.

[0045] When implementing the current-limiting device in parallel with the first bridge arm switch and in series with the second bridge arm switch, refer to... Figure 1 The first terminal of the current-limiting device is electrically connected to the midpoint of the bridge arm, while the second terminal of the current-limiting device is electrically connected to the same busbar of the first bridge arm switching transistor. (Reference) Figure 1For example, the second terminal of the current limiting device and the first bridge arm switch can be electrically connected to the negative busbar of the bridge arm, that is, the first bridge arm switch is electrically connected between the midpoint of the bridge arm and the negative busbar of the bridge arm, and the second bridge arm switch is electrically connected between the midpoint of the bridge arm and the positive busbar of the bridge arm. Of course, in other embodiments, the second terminal of the current limiting device and the first bridge arm switch can be electrically connected to the positive busbar of the bridge arm, that is, the first bridge arm switch is electrically connected between the midpoint of the bridge arm and the positive busbar of the bridge arm, and the second bridge arm switch is electrically connected between the midpoint of the bridge arm and the negative busbar of the bridge arm.

[0046] There are several ways to configure current-limiting devices. For example, refer to... Figures 2-3 Current-limiting devices can include at least one of current-limiting resistors, current-limiting inductors, and current-limiting capacitors. Specifically, a current-limiting device can include only one of these three types; it can include any two of these three types; or it can include all types of these three types. Of course, the number of current-limiting resistors, current-limiting inductors, and current-limiting capacitors in a current-limiting device can be one or more.

[0047] For example, refer to Figures 2-3 Current-limiting devices may include: a current-limiting inductor and a current-limiting capacitor connected in series. For example... Figures 2-3 In this diagram, L2 represents a current-limiting inductor, and C2 represents a current-limiting capacitor. That is, the current-limiting device includes one current-limiting inductor and one current-limiting capacitor, which are connected in series. The first terminal of the current-limiting inductor can be electrically connected to the midpoint of the bridge arm, and the second terminal of the current-limiting inductor can be electrically connected to the first terminal of the current-limiting capacitor. The second terminal of the current-limiting capacitor can be electrically connected to the same busbar of the first bridge arm's switching transistor. For example, refer to... Figure 2 and Figure 3 The second terminal of the current-limiting capacitor can be electrically connected to the negative busbar of the first bridge arm switch. Using a current-limiting device composed of a current-limiting inductor and a current-limiting capacitor connected in series can prevent the bridge arm from being impacted by large pulse currents at the moment of conduction or turn-off. Moreover, compared to directly using a current-limiting resistor, it can reduce the heat generated by the current-limiting device, thereby reducing heating power consumption and improving heating efficiency.

[0048] For example, refer to Figure 3 The battery heating circuit may further include a switching device, which controls the conduction and cutoff between the current limiting device and the bridge arm. That is, by setting the switching device to control the conduction and cutoff between the current limiting device and the bridge arm, it is possible not only to control whether the battery self-heating function is activated, but also to reuse bridge arms from other circuits as bridge arms in this embodiment, facilitating the reuse of bridge arms in this embodiment without affecting the bridge arms' ability to perform different functions at different times.

[0049] There are several ways to configure switching devices. The following are some examples of such configuration methods.

[0050] For example, refer to Figure 3 The switching device may include: a first switch, electrically connected between the current-limiting device and the midpoint of the bridge arm, the first switch being used to control the conduction and cutoff between the current-limiting device and the midpoint of the bridge arm. Specifically, when the first switch is on, conduction occurs between the current-limiting device and the midpoint of the bridge arm; conduction between the current-limiting device and the bridge arm is achieved when the second end of the current-limiting device and itself are on. When the first switch is off, the current-limiting device is cut off from the midpoint of the bridge arm, thereby controlling the cutoff between the current-limiting device and the bridge arm.

[0051] For example, refer to Figure 3 The switching device may include a second switch, which is electrically connected between the current-limiting device and the busbar of the bridge arm. The second switch is used to control the conduction and cutoff between the current-limiting device and the busbar of the bridge arm. Specifically, when the second switch is on, the current-limiting device and the busbar of the bridge arm are connected. When the second end of the current-limiting device and itself are on, the conduction between the current-limiting device and the bridge arm can be achieved. When the second switch is off, the current-limiting device and the busbar of the bridge arm are cut off, thereby controlling the cutoff between the current-limiting device and the bridge arm. Specifically, as mentioned above, the current-limiting device and the first bridge arm switch are electrically connected to the same busbar of the bridge arm. When the first bridge arm switch is electrically connected to the negative busbar of the bridge arm, the second switch is electrically connected between the current-limiting device and the negative busbar of the bridge arm; when the first bridge arm switch is electrically connected to the positive busbar of the bridge arm, the second switch is electrically connected between the current-limiting device and the positive busbar of the bridge arm.

[0052] For example, refer to Figure 3 The switching device may include a third switch. In this case, the current-limiting device consists of at least two devices connected in series. The third switch is electrically connected between any two adjacent devices. That is, the third switch is used to control the conduction and cutoff between the first and second terminals of the current-limiting device, thereby controlling whether the current-limiting device can conduct with the bridge arm. For example, the current-limiting device includes a current-limiting capacitor and a current-limiting inductor connected in series. In this case, the third switch can be electrically connected between the current-limiting capacitor and the current-limiting inductor. When the third switch is on, the current-limiting capacitor and the current-limiting inductor conduct. When the first and second terminals of the current-limiting device are connected to the midpoint of the bridge arm and the busbar of the bridge arm, respectively, conduction between the current-limiting device and the bridge arm can be achieved. When the third switch is off, the current-limiting capacitor and the current-limiting inductor are off, thereby cutting off the current-limiting device from the bridge arm.

[0053] It should be noted that the reference Figure 3In the above embodiments, the first, second, and third switches can be configured in only some or all of them. Of course, when only some are configured, the locations without switches are directly electrically connected. When only one switch is configured, the bridge arm and current-limiting device are turned on when that switch is on, and the bridge arm and current-limiting device are turned off when that switch is off. When two or three switches are configured, the bridge arm and current-limiting device are turned off when some of the switches are off; the bridge arm and current-limiting device are only turned on when all switches are on.

[0054] For example, the bridge arm described above can reuse one of the bridge arms from the inverter, power factor correction circuit, or DC-DC converter to reduce costs. For example, the inverter includes three bridge arms connected in parallel with three phases; the bridge arm in this embodiment can reuse any one of the bridge arms from the inverter. It should be noted that the inverter can be used for DC-to-three-phase conversion. This inverter can be a vehicle inverter or an inverter from other equipment. Similarly, it should be noted that the power factor correction circuit and DC-DC converter described above can be devices from a vehicle or devices from other equipment. The resonant capacitor described above can be an existing capacitor on the same equipment; that is, the resonant capacitor can also reuse capacitors from other circuits to reduce costs.

[0055] In the various embodiments shown above, a self-heating circuit for the battery is formed by a battery inductor, a resonant capacitor, bridge arms, and current-limiting devices. An LC parallel resonant circuit is formed by the battery inductor and the resonant capacitor, and a resonant current is generated in the LC parallel resonant circuit through the first and second bridge arm switches to heat the battery through its internal resistance. The resonant circuit has few components, a simple structure, low impedance, and low energy consumption.

[0056] In addition, this application also provides a heating control method, referring to... Figures 1-3 The heating control method is based on any of the above-mentioned battery heating circuits, and the heating control method includes:

[0057] The first and second bridge arm switches are controlled to alternately turn on and off, generating a resonant current in the LC parallel resonant circuit to heat the battery through its internal resistance.

[0058] In the above scheme, a self-heating circuit for the battery is formed using a battery inductor, resonant capacitor, bridge arms, and current-limiting devices. The battery inductor and resonant capacitor form an LC parallel resonant circuit, and a resonant current is generated in the LC parallel resonant circuit through the first and second bridge arm switches, thereby heating the battery through its internal resistance. This method requires fewer components, has a simple structure, and simplifies heating control. The steps described above are explained in detail below with reference to the accompanying drawings.

[0059] refer to Figures 1-4 By controlling the alternating on and off of the first and second bridge arm switches, a discontinuous discharge current is generated between the second bridge arm switch and the current-limiting device. This generates a resonant current in the LC parallel resonant circuit formed by the battery inductor and resonant capacitor, which heats the battery through its internal resistance. Due to the presence of the current-limiting device, the value of this discharge current is much smaller than the resonant current. However, the magnitude of the discharge current can be adjusted by controlling the duty cycle and / or frequency of the PWM wave control signal of the bridge arm, thereby adjusting the magnitude of the resonant current. In other words, the magnitude of the resonant current generated in the LC parallel resonant circuit can be adjusted. For example, refer to... Figure 4 Ibat represents the waveform of the battery's output current, Ic represents the waveform of the resonant current in the LC parallel resonant circuit, and Isub represents the discharge current through the bridge arm. It can be seen that the resonant current is 2 to 3 times the discharge current. Of course, the ratio between the resonant current and the discharge current can be adjusted according to requirements and device type.

[0060] In related technologies, battery self-heating solutions either require adding a dedicated resonant device between battery packs, resulting in numerous components in the resonant circuit, high overall circuit impedance, and high energy consumption. The solution illustrated in this application not only requires fewer components but also utilizes the battery's internal inductance and resonant capacitor to form an LC parallel resonant circuit. The resonant current flows only in the LC parallel resonant circuit, while the discharge current generated on the bridge arm is much smaller than the resonant current. Therefore, compared to related technologies, the resonant circuit is shorter, has lower impedance, lower energy consumption, and higher heating efficiency.

[0061] For example, various methods can be used to control the alternating on and off of the first and second bridge arm switches to generate a resonant current in the LC parallel resonant circuit. For example, refer to... Figure 5 Controlling the alternating on and off of the first and second bridge arm switches to generate a resonant current in the LC parallel resonant circuit may include:

[0062] Step 1: Determine the target resonant current. The magnitude of the target resonant current can be determined based on factors such as, but not limited to, the battery temperature, the ambient temperature, and the urgency of battery heating. A higher target resonant current can be determined, which, while keeping the battery's internal resistance constant, can improve the battery's heating power and efficiency. This approach is applicable to scenarios where the battery temperature is low, the ambient temperature is low, and the urgency of battery heating is high. Alternatively, a lower target resonant current can be determined, which, while keeping the battery's internal resistance constant, can reduce the battery's heating power and efficiency. This approach is applicable to scenarios where the battery temperature is not particularly low, the ambient temperature is not particularly low, and the urgency of battery heating is not particularly high.

[0063] Step 2: Generate a PWM wave control signal based at least on the target resonant current. After determining the target resonant current, the target resonant current needs to be considered when determining the PWM wave control signal; that is, the target resonant current is used as part or all of the basis for determining the PWM wave control signal.

[0064] Step 3: Based on the PWM wave control signal, control the first and second bridge arm switches to alternately turn on and off to generate the target resonant current in the LC parallel resonant circuit. After generating the PWM wave control signal, the first and second bridge arm switches can be controlled to alternately turn on and off according to the PWM wave control signal to generate the target resonant current in the LC parallel resonant circuit.

[0065] Of course, in other embodiments, it is not necessary to determine the target resonant current in advance. Instead, the first bridge arm switch and the second bridge arm switch can be controlled to turn on and off alternately, and it can be observed whether a resonant current can be generated in the LC parallel resonant circuit.

[0066] For example, when generating a PWM wave control signal based at least on the target resonant current, the frequency and / or duty cycle of the PWM wave control signal can be determined based at least on the target resonant current. Specifically, the frequency of the PWM wave control signal can be determined based only on the target resonant current, or the duty cycle can be determined based only on the target resonant current. Alternatively, both the frequency and duty cycle of the PWM wave control signal can be determined based on the target resonant current.

[0067] For example, when generating a PWM wave control signal based at least on the target resonant current, the frequency of the PWM wave control signal can be determined based on the resonant frequency of the LC parallel resonant circuit; and the duty cycle of the PWM wave control signal can be determined based on the target resonant current. That is, in this embodiment, the frequency of the PWM wave control signal is not determined based on the target resonant current, but only the duty cycle of the PWM wave control signal is determined based on the target resonant current.

[0068] For example, determining the frequency of the PWM wave control signal based on the resonant frequency of the LC parallel resonant circuit can include: using the resonant frequency of the LC parallel resonant circuit as the frequency of the PWM wave control signal, that is, directly using the resonant frequency in the LC parallel resonant circuit as the frequency of the PWM wave control signal. Of course, in other embodiments, any value between 1 / 2 and 3 / 2 of the resonant frequency of the LC parallel resonant circuit can be used as the frequency of the PWM wave control signal.

[0069] For example, as described in the foregoing embodiments, refer to Figure 3 The battery heating circuit may further include a current-limiting device and a switching device, wherein the switching device is used to control the conduction and cutoff between the current-limiting device and the bridge arm. The heating control method may further include: when the battery temperature is below a first temperature threshold, controlling the current-limiting device to conduct with the bridge arm via the switching device, and controlling the bridge arm to generate a resonant current in the LC parallel resonant circuit; when the battery temperature is above a second temperature threshold, controlling the current-limiting device to cut off with the bridge arm via the switching device; wherein the second temperature threshold is greater than the first temperature threshold.

[0070] Specifically, the battery temperature can be periodically measured, and it can be determined whether the battery temperature is below a first temperature threshold. This first temperature threshold is preset. For example, the first temperature threshold can be 0°C. When the determination result is that the battery temperature is below the first temperature threshold, it indicates that the battery temperature is too low and there is a need to heat the battery. At this time, the current limiting device can be controlled to conduct through the switching device, and then the bridge arm can be controlled to generate a resonant current in the LC parallel resonant circuit to heat the battery through its internal resistance.

[0071] During the battery heating process, the battery temperature is periodically monitored and it is determined whether the battery temperature exceeds a second temperature threshold. This second temperature threshold is also preset and is greater than the first temperature threshold; for example, the second temperature threshold can be 20°C. When the determination result shows that the battery temperature is greater than the second temperature threshold, it indicates that the battery has been heated to a relatively high temperature, and heating can be stopped. At this time, the current limiting device and the bridge arm can be turned off by controlling the switching device, and at least one of the first and second bridge arm switches can be turned off. Specifically, one of the first and second bridge arm switches can be turned off, or both of the first and second bridge arm switches can be turned off, thereby stopping the self-heating of the battery.

[0072] Furthermore, when the bridge arm is a bridge arm in other equipment of the reused vehicle, during vehicle operation, since the current limiting device and the bridge arm are turned off by the switching device, and there is no current periodically discharging at the resonant frequency in other circuits, no resonant current will be formed between the battery inductor and the resonant capacitor. That is, there will be no situation where the self-heating function is not turned on (the switching device controls the current limiting device and the bridge arm to conduct), and there is no resonant current between the battery inductor and the resonant capacitor.

[0073] For example, the capacitance value of the resonant capacitor can be determined based on the battery inductance. Specifically, the battery inductance can be measured to obtain the inductance value L1, and 1uH (microhenry) corresponds to 1uF (microvolt) as the capacitance value of the resonant capacitor C1.

[0074] For example, the resonant frequency of an LC parallel resonant circuit can also be calculated using the following formula:

[0075] f = 1 / [2*π*(L1*C1)] 1 / 2 ]

[0076] Where f is the resonant frequency of the LC parallel resonant circuit.

[0077] The following example, using a vehicle battery as an example, illustrates a specific heating control method.

[0078] S00, measure the inductance of the battery itself and obtain the inductance value L1 of the battery inductance. According to the correspondence of 1uH (microhenry) to 1uF (microgen), obtain the capacitance value of the resonant capacitor C1.

[0079] S01, parallel resonant capacitor C1, forms a parallel LC resonant circuit between the battery inductor and the resonant capacitor, and the resonant frequency of the LC parallel resonant circuit is calculated according to the resonance formula.

[0080] S02, connect the resonant capacitor C1 in parallel with the battery;

[0081] S03, one bridge arm of the inverter is reused as the bridge arm in this embodiment of the application. Specifically, any one of the A-phase bridge arm, B-phase bridge arm, and C-phase bridge arm of the inverter can be reused. A current-limiting inductor L2 and a current-limiting capacitor C2 are connected in parallel as current-limiting devices in the first bridge arm switch (upper bridge arm switch or lower bridge arm switch). The current-limiting inductor L2 and the current-limiting capacitor C2 are connected in series for current limiting. Figure 1 As shown;

[0082] S04 controls the switching of the multiplexed bridge arms in the inverter according to the resonant frequency.

[0083] S05, adjust the duty cycle of the inverter's PWM wave control signal so that the resonant current generated by the LC parallel resonant circuit between the battery and the resonant capacitor is the target resonant current.

[0084] S06, When the vehicle is parked and the battery temperature is detected to be lower than the first temperature threshold, such as below 0°C, the current limiting device branch consisting of the current limiting inductor L2 and the current limiting capacitor C2 connected in series is turned on, and a signal is sent to the inverter controller of the vehicle to turn on the battery self-heating function.

[0085] S07, the inverter controller is built into the vehicle itself. After the battery self-heating function is turned on, the controller controls the inverter to periodically discharge through the current-limiting inductor L2 and the current-limiting capacitor C2 at the resonant frequency.

[0086] S08, the LC parallel resonant circuit consists of a battery and a resonant capacitor C1. The resonant capacitor C1 can be added or replaced by an existing one in the drive assembly. The resonant current flows through the battery and heats the battery through its internal resistance.

[0087] S09, when the battery temperature is detected to rise to the second temperature threshold, the switching devices on the current limiting inductor L2 and the current limiting capacitor C2 can be disconnected, and a signal to turn off the self-heating function is sent to the inverter controller.

[0088] S10, when the bridge arm is the bridge arm of other equipment in the reused vehicle, when the vehicle is running, because the current limiting device and the bridge arm are turned off by the switching device, and there is no current periodically discharging at the resonant frequency in other circuits, no resonant current will be formed between the battery inductor and the resonant capacitor. That is, there will be no situation where the self-heating function is not turned on (the switching device controls the current limiting device and the bridge arm to conduct), and there is no situation where there is a resonant current between the battery inductor and the resonant capacitor.

[0089] In the various embodiments shown above, a self-heating circuit for the battery is formed by a battery inductor, a resonant capacitor, bridge arms, and current-limiting devices. An LC parallel resonant circuit is formed by the battery inductor and the resonant capacitor, and a resonant current is generated in the LC parallel resonant circuit through the first and second bridge arm switches to heat the battery through its internal resistance. Compared to related technologies, the resonant circuit of this application has fewer components, a simpler structure, lower impedance, lower energy consumption, and simplifies the difficulty of heating control.

[0090] In related technologies, battery self-heating solutions either require adding a dedicated resonant device between battery packs, resulting in numerous components in the resonant circuit, high overall circuit impedance, and high energy consumption. The solution illustrated in this application not only requires fewer components but also utilizes the battery's internal inductance and resonant capacitor to form an LC parallel resonant circuit. The resonant current flows only in the LC parallel resonant circuit, while the discharge current generated on the bridge arm is much smaller than the resonant current. Therefore, compared to related technologies, the resonant circuit is shorter, has lower impedance, lower energy consumption, and higher heating efficiency.

[0091] In some embodiments, compared to related battery self-heating solutions, some embodiments of this application include a resonant capacitor connected in parallel to the battery, and one bridge arm of the inverter is reused as the bridge arm in this embodiment. A current-limiting device is connected in parallel to the first bridge arm switch (which can be either the upper or lower bridge arm switch). The bridge arm is controlled to periodically store energy for the battery inductor through the current-limiting device, forming a resonant current in the LC parallel resonant circuit between the battery inductor and the resonant capacitor. The discharge current on the bridge arm switch is much smaller than the resonant current and is discontinuous, thereby reducing the energy consumption of the bridge arm switch and the heat generation of the bridge arm. In some embodiments, the discharge current can be adjusted by adjusting the duty cycle and / or frequency of the PWM wave control signal controlling the bridge arm, thereby adjusting the magnitude of the resonant current.

[0092] Compared with the aforementioned related technologies, the solution in this application embodiment has fewer components flowing through the resonant circuit (only the battery and resonant capacitor), lower impedance, lower energy consumption, less energy required to achieve the same battery temperature rise, and higher heating efficiency. In some embodiments, the bridge arm reuses bridge arms such as, but not limited to, those in an inverter, saving costs. Furthermore, the discharge circuit consists of a current-limiting device connected in parallel with the first bridge arm switch, requiring no other components. Parameter settings are flexible, and the bridge arm can be easily controlled via software to generate resonant current in the LC parallel resonant circuit.

[0093] For example, compared to related technology one, the current-limiting device in this application can be connected in parallel with the upper bridge arm switch or the lower bridge arm switch. The parallel current-limiting devices (current-limiting capacitor and current-limiting inductor) are used for current-limiting discharge. Furthermore, the resonant current in the embodiments of this application is between the battery inductor and the resonant capacitor within the battery, and some embodiments reuse the inverter's bridge arm to save costs. In contrast, related technology one uses a newly connected bridge arm, with the lower bridge arm switch connected in parallel with an inductor and capacitor, to control the newly connected bridge arm, forming a self-heating current between the inductor and capacitor connected in parallel with the lower bridge arm switch and the battery. It can be seen that the resonant current loops of the two are different, and the functions of the inductor and capacitor connected in parallel with the bridge arm are different.

[0094] Compared to related technology 2, this application connects a resonant capacitor in parallel to the battery and utilizes the battery's own inductance to form an LC parallel resonant circuit to heat the battery. Related technology 2, on the other hand, incorporates an energy storage device, with charging and discharging occurring between the energy storage device and the battery pack. It can be seen that the heating circuits of the two technologies are different.

[0095] Compared to related technology three, the current-limiting device in this application can be connected in parallel with either the upper or lower bridge arm switching transistor of the bridge arm. The parallel current-limiting devices (current-limiting capacitor and current-limiting inductor) are used for current-limiting discharge. Furthermore, in the embodiments of this application, the resonant current is between the battery inductor and the resonant capacitor within the battery, and some embodiments reuse the inverter's bridge arm to save costs. In contrast, related technology three involves external winding inductors and capacitors, and the resonant self-heating circuit is located between the battery, winding inductor, and capacitor. It can be seen that the resonant circuits of the two are not the same.

[0096] Compared with related technology four, the solution of this application embodiment does not require the participation of a motor, the motor itself does not generate heat, and the heating circuits of the two are different.

[0097] Furthermore, embodiments of this application also provide a controller, referencing Figure 6 The controller includes a storage medium and a processor. The storage medium stores a computer program that is executed by the processor. When the computer program is executed by the processor, it causes the processor to perform any of the heating control methods described above. For example, the controller can be a controller for a vehicle inverter, a vehicle controller, a battery management system controller, etc.

[0098] Figure 6 A schematic block diagram of a controller 100 according to an embodiment of this application is shown. Figure 6 As shown, the controller 100 according to an embodiment of this application may include a storage medium 110 and a processor 120. The storage medium 110 stores a computer program that is executed by the processor 120. When the computer program is executed by the processor 120, the processor 120 performs the heating control method described above according to an embodiment of this application. Those skilled in the art can understand the specific operation of the controller 100 deployment device according to the embodiments of this application in conjunction with the foregoing content; for the sake of brevity, it will not be described again here.

[0099] The storage medium 110 may include, for example, a memory card of a smartphone, a storage component of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disc read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. A computer-readable storage medium may be any combination of one or more computer-readable storage media.

[0100] Furthermore, embodiments of this application also provide a battery system, referencing... Figures 1-6 The battery system includes: any of the above-described battery heating circuits, or any of the above-described controllers. For example, the battery system can be a battery system on a vehicle, in which case the battery in the battery system can be a power battery or a storage battery on the vehicle. For example, the battery system can also be a battery system for an energy storage station, in which case the battery in the battery system can be an energy storage battery in the energy storage station.

[0101] Furthermore, embodiments of this application also provide an electrical device, see reference. Figures 1-6 The electrical device includes: any of the aforementioned battery heating circuits, any of the aforementioned controllers, or any of the aforementioned battery systems. For example, the electrical device can be a battery-equipped device such as, but not limited to, a vehicle, aircraft, ship, home appliance, or energy storage cabinet. When the electrical device is a vehicle, for example, the vehicle can be any vehicle equipped with a battery, such as, but not limited to, an electric vehicle, a fuel-powered vehicle, a hybrid electric vehicle, or a gas-electric hybrid vehicle. That is, any vehicle equipped with a battery falls within the scope of the vehicles shown in this patent.

[0102] The present invention has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the invention to the scope of the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heating control method, characterized in that, The heating control method is based on a battery heating circuit, which includes: A battery, which has battery inductance; A resonant capacitor is connected in parallel with the battery so that the resonant capacitor and the battery inductance form an LC parallel resonant circuit; and The bridge arm is connected in parallel with the battery; the bridge arm includes a first bridge arm switch and a second bridge arm switch connected in series. A current-limiting device is connected in parallel with the first bridge arm switch and in series with the second bridge arm switch; A switching device is used to control the on and off states between the current limiting device and the bridge arm; The switching device includes: A first switch is electrically connected between the current-limiting device and the midpoint of the bridge arm; or / and, The second switch is electrically connected between the current-limiting device and the busbar of the bridge arm; or / and, The third switch, wherein the current limiting device consists of at least two devices connected in series, and the third switch is electrically connected between any two adjacent devices; The bridge arm is a bridge arm of an inverter, a power factor correction circuit, or a DC-DC converter; The heating control method includes: The first bridge arm switch and the second bridge arm switch are controlled to alternately turn on and off, generating a resonant current in the LC parallel resonant circuit to heat the battery through the internal resistance of the battery. The step of controlling the first bridge arm switch and the second bridge arm switch to alternately turn on and off to generate the resonant current in the LC parallel resonant circuit includes: Determine the target resonant current; At least based on the target resonant current, a PWM wave control signal is generated; According to the PWM wave control signal, the first bridge arm switch and the second bridge arm switch are controlled to alternately turn on and off in order to generate the target resonant current in the LC parallel resonant circuit. Wherein, generating a PWM wave control signal based at least on the target resonant current includes: The frequency of the PWM wave control signal is determined based on the resonant frequency of the LC parallel resonant circuit. The duty cycle of the PWM wave control signal is determined based on the target resonant current.

2. The heating control method as described in claim 1, characterized in that, Determining the frequency of the PWM wave control signal based on the resonant frequency of the LC parallel resonant circuit includes: The resonant frequency of the LC parallel resonant circuit is used as the frequency of the PWM wave control signal.

3. The heating control method according to any one of claims 1 to 2, characterized in that, The battery heating circuit further includes a current limiting device and a switching device, wherein the switching device is used to control the conduction and cutoff between the current limiting device and the bridge arm; The heating control method further includes: When the temperature of the battery is lower than the first temperature threshold, the current limiting device is controlled to conduct with the bridge arm by the switching device, and the bridge arm is controlled to generate a resonant current in the LC parallel resonant circuit. When the temperature of the battery is higher than the second temperature threshold, the current limiting device and the bridge arm are turned off by the switching device, and at least one of the first bridge arm switching transistors and the second bridge arm switching transistors is turned off; wherein, the second temperature threshold is greater than the first temperature threshold.

4. A controller, characterized in that, include: A storage medium and a processor, wherein the storage medium stores a computer program that is executed by the processor, the computer program, when executed by the processor, causes the processor to perform the heating control method as described in any one of claims 1 to 3.

5. A battery system, characterized in that, include: The controller as described in claim 4.

6. An electrical appliance, characterized in that, include: The controller as claimed in claim 4, or the battery system as claimed in claim 5.

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