Charging device and method for heating a battery

Abstract

This application discloses a charging device comprising: a DC source; a bidirectional DC converter connected between the DC source and a charging port of the charging device; a pulse heating module connected in parallel with the bidirectional DC converter; and a controller configured to, upon receiving a heating request, select one of the pulse heating module and the bidirectional DC converter to heat the battery based on the battery's heating frequency requirements. This application also relates to a battery heating method and storage medium.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a charging device and a method for heating a battery. Background Art

[0002] With the development of new energy technologies, batteries are being used as power sources in an increasing number of fields. Due to their high energy density, rechargeability, safety, and environmental friendliness, batteries are widely used in new energy vehicles, consumer electronics, energy storage systems, and other fields.

[0003] However, batteries are subject to certain limitations when used in low-temperature environments. Specifically, in low-temperature environments, the battery's charge and discharge capacity will be severely degraded. Charging and discharging the battery will also cause a decrease in lifespan, and charging the battery may even cause irreversible damage. Therefore, to ensure normal use of the battery in low-temperature environments, it is necessary to heat the battery. Summary of the Invention

[0004] In view of the above problems, the present application proposes a charging device and a method for heating a battery to solve the problem of limited use of the battery in a low temperature environment.

[0005] To this end, a first aspect of the present invention provides a charging device, the charging device comprising:

[0006] DC source;

[0007] a bidirectional DC converter connected between the DC source and the charging port of the charging device;

[0008] A pulse heating module is connected in parallel with the bidirectional DC converter;

[0009] A controller configured to:

[0010] When a heating request is received, one of the pulse heating module and the bidirectional DC converter is selected to heat the battery according to the heating frequency requirement of the battery.

[0011] In the embodiments of the present application, using a charging device to heat low-temperature batteries can eliminate the need for onboard battery heating devices and achieve rapid pulse heating at low vehicle temperatures without increasing vehicle costs. Furthermore, in the embodiments of the present application, different heating devices are selected to heat the battery at different frequencies, depending on the heating frequency requirements of the battery, making the charging device suitable for heating various types of batteries.

[0012] In some embodiments, the controller is configured to:

[0013] When the heating frequency requirement is less than a preset first frequency, selecting the bidirectional DC converter to heat the battery; and

[0014] When the heating frequency requirement is greater than or equal to a preset first frequency, the pulse heating module is selected to heat the battery.

[0015] In the embodiments of the present application, pulse heating in the lower frequency range is achieved through a bidirectional DC converter, and pulse heating in the higher frequency range is achieved through a pulse heating module, allowing the charging device to cover the full frequency range of pulse waveforms. In some embodiments of the present application, the preset first frequency is 100 Hz. In addition, in some embodiments of the present application, the maximum frequency that the pulse heating module can be applied to is 2 kHz.

[0016] In some embodiments, the controller is configured to: when starting to heat the battery, control the bidirectional DC converter or the pulse heating module so that the first half of the first cycle of the pulse current that heats the battery is discharged by the battery.

[0017] In the embodiments of the present application, by controlling the discharge of the battery in the first half of the first cycle, lithium deposition due to charging of the battery at ultra-low temperatures is avoided. It should be understood that some low-temperature battery cells also allow for short-term charging. Therefore, in other embodiments of the present application, the controller can be configured to: when starting to heat the battery, control the bidirectional DC converter or the pulse heating module so that the battery is charged in the first half of the first cycle of the pulse current that heats the battery.

[0018] In some embodiments, the controller is configured to: when the heating frequency requirement is less than a preset second frequency, control the above-mentioned bidirectional DC converter so that the energy released by the battery during battery discharge is fed back to the above-mentioned DC source, wherein the preset second frequency is less than the preset first frequency.

[0019] In the implementation scheme of the present application, due to the use of a bidirectional DC converter, electric energy can be fed back to the DC source without storing the energy in the energy storage element of the DC converter, thereby reducing the requirements for the energy storage element and switching devices in the DC converter.

[0020] In some embodiments, the DC source includes a bidirectional rectifier connected to a power grid, and the controller is configured to: when the heating frequency requirement is less than a preset second frequency, control the rectifier and the bidirectional DC converter so that the energy released by the battery during battery discharge is fed back to the power grid, wherein the preset second frequency is less than the preset first frequency.

[0021] In the implementation scheme of the present application, due to the use of a bidirectional rectifier, electric energy can be fed back to the power grid; specifically, when a bidirectional DC converter is used to generate a pulse heating current, if the pulse frequency is low, the energy is fed back to the power grid through the bidirectional rectifier without storing the energy in the energy storage element of the DC converter, thereby reducing the requirements for the energy storage elements and switching devices in the rectifier and DC converter.

[0022] In other embodiments, the DC source includes an energy storage device. In the embodiments of the present application, since the DC source includes an energy storage device, energy can be fed back to the energy storage device for storage when the pulse frequency is low. Furthermore, the energy provided to the battery to be heated can come from the energy storage device, without the need for a rectifier connected to the power grid. In some specific embodiments of the present application, the energy storage device can include an energy storage battery and / or a supercapacitor.

[0023] In some embodiments, the controller is configured to: when the heating frequency requirement is greater than or equal to a preset second frequency and less than a preset first frequency, control the above-mentioned bidirectional DC converter so that the energy released by the battery during battery discharge is stored in the energy storage element of the above-mentioned bidirectional DC converter, wherein the preset second frequency is less than the preset first frequency.

[0024] In some embodiments, the DC source includes a rectifier connected to a power grid, the charging device is configured to monitor the voltage of the battery, and the controller is configured to:

[0025] When the voltage of the battery is lower than a preset voltage threshold of the initial voltage of the battery, the rectifier is controlled to supplement the battery, wherein the initial voltage is the voltage when the battery starts to be heated.

[0026] In the embodiment of the present application, the battery is supplemented with power through a rectifier, so that the battery can be heated by a pulse current even when the voltage is low, and the situation in which the battery cannot be heated when the state of charge is low will not occur.

[0027] In some specific embodiments, when the battery is heated by the bidirectional DC converter, the controller is configured to control the rectifier and the bidirectional DC converter to adjust the balance between charging energy and discharging energy of the pulse-heated battery.

[0028] In the embodiment of the present application, by adjusting the balance between charging energy and discharging energy, it is ensured that the energy stored in the battery does not decrease and the state of charge of the battery does not decrease.

[0029] In some specific embodiments, when the battery is heated by the above-mentioned pulse heating module, the controller is configured to control the above-mentioned rectifier so that the output voltage of the above-mentioned rectifier is equal to a preset voltage value during the period when the energy storage element of the above-mentioned pulse heating module charges the battery, and the preset voltage value is greater than or equal to the initial voltage of the battery.

[0030] In an embodiment of the present application, the output voltage of the rectifier is controlled to be greater than or equal to the initial voltage of the battery during charging of the battery, so that the battery can replenish the energy released and consumed during charging, and the battery reaches energy balance during the pulse charge and discharge process, maintaining the battery voltage at the initial voltage.

[0031] In one embodiment of the present application, the preset voltage value is slightly greater than the initial voltage of the battery.

[0032] In some embodiments, the charging device includes a plurality of bidirectional DC converters connected in parallel with each other, and when the heating frequency requirement is less than a preset first frequency, one or more of the plurality of bidirectional DC converters heats the battery.

[0033] In some embodiments, the charging device includes a plurality of pulse heating modules connected in parallel with each other, and when the heating frequency requirement is greater than or equal to a preset first frequency, one or more of the plurality of pulse heating modules heats the battery.

[0034] A second aspect of the present invention provides a method for heating a battery, the method comprising:

[0035] receiving a heating request and a heating frequency requirement for the battery;

[0036] In response to a heating request, one of a pulse heating module and a bidirectional DC converter connected between a DC source and a battery is selected to heat the battery according to a heating frequency requirement.

[0037] In the embodiments of the present application, different heating devices are selected to heat the battery at different frequencies according to the heating frequency requirements of the battery, which can be applied to heating various types of batteries.

[0038] In some embodiments, the method comprises:

[0039] When the heating frequency requirement is lower than a preset first frequency, the battery is heated by the bidirectional DC converter; and

[0040] When the heating frequency requirement is greater than or equal to a preset first frequency, the pulse heating module heats the battery.

[0041] In embodiments of the present application, pulse heating in a lower frequency range is achieved by a bidirectional DC converter, and pulse heating in a higher frequency range is achieved by a pulse heating module, thereby covering the full frequency range of pulse waveforms. In some embodiments of the present application, the preset first frequency is 100 Hz. In addition, in some embodiments of the present application, the maximum frequency that the pulse heating module can be applied to is 2 kHz.

[0042] In some embodiments, the method comprises:

[0043] When starting to heat the battery, the bidirectional DC converter or the pulse heating module is controlled so that the battery discharges the first half of the first cycle of the pulse current for heating the battery.

[0044] In the embodiments of the present application, by controlling the discharge of the battery in the first half of the first cycle, lithium deposition due to charging of the battery at ultra-low temperatures is avoided. It should be understood that some low-temperature battery cells also allow for short-term charging. Therefore, in other embodiments of the present application, the controller can be configured to: when starting to heat the battery, control the bidirectional DC converter or the pulse heating module so that the battery is charged in the first half of the first cycle of the pulse current that heats the battery.

[0045] In some embodiments, the method comprises:

[0046] When the heating frequency requirement is lower than a preset second frequency, the bidirectional DC converter is controlled so that the energy released by the battery during battery discharge is fed back to the DC source, wherein the preset second frequency is lower than the preset first frequency.

[0047] In the implementation scheme of the present application, due to the use of a bidirectional DC converter, electric energy can be fed back to the DC source without storing the energy in the energy storage element of the DC converter, thereby reducing the requirements for the energy storage element and switching devices in the DC converter.

[0048] In some embodiments, the DC source comprises a bidirectional rectifier connected to a power grid, and the method comprises:

[0049] When the heating frequency requirement is lower than a preset second frequency, the rectifier and the bidirectional DC converter are controlled so that the energy released by the battery is fed back to the power grid during battery discharge, wherein the preset second frequency is lower than the preset first frequency.

[0050] In some embodiments, the DC source includes an energy storage device. In the embodiments of the present application, since the DC source includes an energy storage device, energy can be fed back to the energy storage device for storage when the pulse frequency is low. Furthermore, the energy provided to the battery to be heated can come from the energy storage device, without the need for a rectifier connected to the power grid. In some specific embodiments of the present application, the energy storage device can include an energy storage battery and / or a supercapacitor.

[0051] In some embodiments, the method comprises:

[0052] When the heating frequency requirement is greater than or equal to a preset second frequency and less than a preset first frequency, the bidirectional DC converter is controlled so that energy released by the battery during battery discharge is stored in the energy storage element of the bidirectional DC converter, wherein the preset second frequency is less than the preset first frequency.

[0053] In some embodiments, the DC source comprises a rectifier connected to a power grid, and the method comprises:

[0054] monitoring the battery voltage; and

[0055] When the voltage of the battery is lower than a preset voltage threshold of the initial voltage of the battery, the rectifier is controlled to supplement the battery, wherein the initial voltage is the voltage when the battery starts to be heated.

[0056] In the embodiment of the present application, the battery is supplemented with power through a rectifier, so that the battery can be heated by a pulse current even when the voltage is low, and the situation in which the battery cannot be heated when the state of charge is low will not occur.

[0057] In some embodiments, the method comprises:

[0058] When the battery is heated by the bidirectional DC converter, the rectifier and the bidirectional DC converter are controlled to adjust the balance between the charging energy and the discharging energy of the pulse heating battery.

[0059] In some embodiments, the method comprises:

[0060] When the battery is heated by the pulse heating module, the rectifier is controlled so that the output voltage of the rectifier is equal to a preset voltage value during the period when the energy storage element of the pulse heating module charges the battery, and the preset voltage value is greater than or equal to the initial voltage of the battery.

[0061] In some embodiments, a plurality of bidirectional DC converters connected in parallel are connected between the DC source and the battery, and when the heating frequency requirement is less than a preset first frequency, the battery is heated by one or more of the plurality of bidirectional DC converters.

[0062] In some embodiments, multiple pulse heating modules connected in parallel with each other are connected between the DC source and the battery, and when the heating frequency is required to be greater than or equal to a preset first frequency, the battery is heated by one or more of the multiple pulse heating modules.

[0063] A third aspect of the present application provides a storage medium storing instructions. When the instructions are executed by a computing device, the processor implements the method for heating a battery according to the second aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings required for use in the embodiments of this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without inventive work. In the drawings:

[0065] Figure 1 1 illustrates a block diagram of a charging device 100 according to one embodiment of the present application;

[0066] Figure 2 A flow chart illustrating a method 200 of heating a battery according to one embodiment of the present application is shown;

[0067] Figure 3 1 illustrates a block diagram of a charging device 300 according to one embodiment of the present application;

[0068] Figure 4 1 illustrates a block diagram of a charging device 400 according to another embodiment of the present application;

[0069] Figure 5 A flow chart illustrating a method 500 for heating a battery according to another embodiment of the present application is shown;

[0070] Figure 6 1 illustrates a block diagram of a charging device 600 according to another embodiment of the present application;

[0071] Figure 7 1 illustrates a block diagram of a charging device 700 according to yet another embodiment of the present application;

[0072] Figure 8 A flow chart illustrating a battery charging method 800 according to one embodiment of the present application is shown;

[0073] Figures 9a to 9e A schematic diagram illustrating a topological structure of a bidirectional DC converter in a charging device according to the present application;

[0074] Figure 10a and Figure 10b A schematic diagram illustrating the structure of a bidirectional DC converter in a charging device according to the present application;

[0075] Figures 11a to 11c Illustrated Figure 10b Waveform diagrams of different modulation strategies of the bidirectional DC converter; and

[0076] Figures 12a to 12h Illustrated Figure 10b The bidirectional DC converter Figure 11a The working mode under the modulation strategy. DETAILED DESCRIPTION

[0077] The following embodiments of the present application are described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0078] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0079] In the description of the embodiments of the present application, technical terms such as "first" and "second" are used only to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary and secondary relationship of the indicated technical features, unless otherwise specified.

[0080] Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0081] In the description of the embodiments of this application, the term "and / or" is merely a description of the association relationship between related objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0082] In the description of the embodiments of the present application, the term "plurality" refers to more than two (including two), unless otherwise clearly specified and specifically defined. In the description of the embodiments of the present application, unless otherwise clearly specified and defined, technical terms such as "connected" and "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0083] If steps are recited in a sequential order in this specification or claims, this does not necessarily mean that embodiments or aspects are limited to the recited order. Rather, it is conceivable that the steps may be performed in a different order or in parallel with one another, unless one step builds upon another, which absolutely requires that the building step be performed later (however, this will become clear in individual cases). Therefore, the recited order may be a preferred embodiment.

[0084] Currently, batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As battery applications continue to expand, market demand is also growing.

[0085] The inventors of this application have discovered that on-board rapid heating solutions require additional vehicle costs and are often only suitable for specific vehicle models. Different vehicle models may have different types of batteries, and different types of batteries may have different internal resistances, requiring heating with pulsed currents of varying frequencies and amplitudes. Otherwise, the battery may experience lithium plating due to the rapid deintercalation of lithium ions from the positive electrode and the inability of lithium ions to be equally intercalated into the negative electrode.

[0086] Furthermore, the inventors of this application have discovered that when the battery charge is low, the remaining energy in the battery is insufficient to heat the battery to a usable temperature. Furthermore, when charging the battery in a cold environment, users often have to wait for a long time in the cold environment until the battery is heated to a charging temperature, which results in a very poor user experience.

[0087] Based on the above findings, in order to reduce the cost of electrical devices loaded with batteries and achieve rapid heating of the batteries when the remaining energy is low, the inventors designed a charging device. By integrating the battery low-temperature rapid heating technology, the rapid heating device on the electrical device side can be eliminated, and different devices can be selected according to the heating frequency requirements of the battery to generate pulse heating current to adapt to different types of batteries.

[0088] Figure 1 1 illustrates a block diagram of a charging device 100 according to one embodiment of the present application. Figure 1 As shown, the charging device 100 includes a DC source 102, a pulse heating module 104, a bidirectional DC converter 106, and a main controller 108. The pulse heating module 104 and the bidirectional DC converter 106 are connected between the DC source 102 and charging ports 109 and 110 of the charging device 100, and the pulse heating module 104 and the bidirectional DC converter 106 are connected in parallel with each other. The charging ports 109 and 110 of the charging device 100 are used to connect to the battery BT1. The main controller 108 controls the operation of the DC source 102, the pulse heating module 104, and the bidirectional DC converter 106.

[0089] The following combination Figure 2 Further description Figure 1 implementation plan, Figure 2 A flow chart of a method 200 for heating a battery according to one embodiment of the present application is illustrated. Figure 2 As shown, in step 202, a heating request and a heating frequency requirement of the battery BT1 are received; however, in response to the heating request, according to the heating frequency requirement, one of the pulse heating module 104 and the bidirectional DC converter 106 connected between the DC source 102 and the battery BT1 is selected to heat the battery BT1, step 204.

[0090] In the embodiments of the present application, using a charging device to heat low-temperature batteries can save on onboard battery heating devices and achieve pulsed rapid heating of the vehicle at low temperatures without increasing vehicle costs. Furthermore, in the embodiments of the present application, different heating devices are selected to heat the battery at different frequencies, depending on the heating frequency requirements of the battery. This allows the charging device to be applied to various types of batteries, and therefore to various types of vehicles.

[0091] Figure 3 FIG. 1 illustrates a block diagram of a charging device 300 according to an embodiment of the present application. Figure 3 As shown, the DC source 102 includes a rectifier 1021 , the AC side of the rectifier 1021 is used to connect to the power grid, and the DC side of the rectifier 1021 is connected to the pulse heating module 104 and the bidirectional DC converter 106 .

[0092] Figure 4 FIG. 4 illustrates a block diagram of a charging device 400 according to another embodiment of the present application. Figure 4As shown, the DC source 102 includes a rectifier 1021 and an energy storage device 1022. The AC side of the rectifier 1021 is used to connect to the power grid, and the DC side of the rectifier 1021 is connected to the energy storage device 1022, the pulse heating module 104 and the bidirectional DC converter 106. Therefore, the energy storage device 1022 can provide energy to the battery BT1, or the power grid can provide energy to the battery BT1 through the rectifier 1021. It should be understood that Figure 4 This is an exemplary embodiment of the present application. In other embodiments of the present application, the DC source 102 may include only the energy storage device 1022 or only the energy storage device 1022. In some embodiments, the energy storage device 1022 may include an energy storage battery and / or a supercapacitor.

[0093] Figure 5 A flow chart of a method 500 for heating a battery according to another embodiment of the present application is illustrated. Figure 5 As shown, in step 502, a heating request and a heating frequency requirement for battery BT1 are received. Then, in step 504, a determination is made as to whether the heating frequency requirement is greater than or equal to a preset first frequency. In some embodiments of the present application, the preset first frequency is 100 Hz. If the heating frequency requirement is greater than or equal to the preset first frequency, the process proceeds to step 506, where the pulse heating module 104 heats battery BT1.

[0094] In some embodiments of the present application, when starting to heat the battery BT1, the main controller 108 controls the pulse heating module 104 so that the first half of the first cycle of the pulse current that heats the battery BT1 is discharged by the battery BT1. The reason for this arrangement is that the inventors of the present application observed the movement law of lithium ions in practice and found that at lower temperatures, the negative electrode of the battery has insufficient space for lithium embedding. If the battery is charged at this time, lithium precipitation may occur. The inventors of the present application also found that some low-temperature battery cells also allow short-term charging. Therefore, in some other embodiments of the present application, when starting to heat the battery BT1, the main controller 108 can control the pulse heating module 104 so that the first half of the first cycle of the pulse current that heats the battery BT1 is charged to the battery BT1.

[0095] During the period when the pulse heating module 104 heats the battery BT1, the voltage of the battery BT1 is monitored, step 508. In step 510, it is determined whether the voltage of the battery BT1 is lower than the voltage threshold preset for the initial voltage. If the voltage of the battery BT1 is lower than the voltage threshold preset for the initial voltage, then during the period when the energy storage element of the pulse heating module 104 charges the battery BT1, the output voltage of the rectifier 1021 is controlled to be equal to a preset voltage value, step 512, and the preset voltage value is greater than or equal to the initial voltage of the battery BT1. If the voltage of the battery BT1 is not lower than the voltage threshold preset for the initial voltage, then the process returns to step 508 and continues to monitor the voltage of the battery BT1. In some embodiments of the present application, the preset voltage value is slightly greater than the initial voltage of the battery BT1. In an embodiment of the present application, during the period when the battery BT1 is charged, the output voltage of the rectifier 1021 is controlled to be greater than or equal to the initial voltage of the battery BT1, so that the battery BT1 can make up for the energy released and consumed during the charging period, and the battery BT1 reaches energy balance during the pulse charging and discharging process, and the voltage of the battery BT1 is maintained at the initial voltage.

[0096] If it is determined in step 504 that the heating frequency requirement is less than the preset first frequency, the process proceeds to step 514, and the DC converter 106 heats the battery BT1. In some embodiments of the present application, when starting to heat the battery BT1, the main controller 108 controls the DC converter 106 so that the first half of the first cycle of the pulse current for heating the battery BT1 is discharged by the battery BT1. Since some low-temperature battery cells also allow short-term charging, in other embodiments of the present application, when starting to heat the battery BT1, the main controller 108 can control the DC converter 106 so that the first half of the first cycle of the pulse current for heating the battery BT1 is charged to the battery BT1.

[0097] When the DC converter 106 is heating the battery BT1, a determination is made as to whether the required heating frequency is less than a preset second frequency (step 516). In some embodiments of the present application, the preset second frequency is 50 Hz; it should be understood that the preset second frequency can be set to other values based on actual needs. In some embodiments of the present application, the rectifier 1021 is a bidirectional rectifier, meaning that the bidirectional rectifier 1021 can both rectify AC power from the grid into DC power and invert DC power into AC power for feeding back to the grid. If the required heating frequency is less than the preset second frequency, the main controller 108 controls the DC converter 106 and the bidirectional rectifier 1021 to feed energy released by the battery BT1 back to the grid during discharge (step 518). It should be understood that in some embodiments including the energy storage device 1022, if the required heating frequency is less than the preset second frequency, pulse energy can be exchanged between the energy storage device 1022 and the battery BT1 to heat the battery BT1; specifically, the DC converter 106 is controlled to feed energy released by the battery BT1 back to the energy storage device 1022 during discharge. If the heating frequency requirement is greater than or equal to the preset second frequency, the main controller 108 controls the DC converter 106 and the rectifier 1021 to store the energy released by the battery BT1 in the energy storage element of the DC converter 106 during battery discharge, step 520 .

[0098] During the heating of the battery BT1 by the DC converter 106, the voltage of the battery BT1 is monitored, step 522. In step 524, it is determined whether the voltage of the battery BT1 is lower than the voltage threshold preset for the initial voltage. If the voltage of the battery BT1 is lower than the voltage threshold preset for the initial voltage, the main controller 108 controls the DC converter 106 and the rectifier 1021 to adjust the balance of the charging energy and the discharging energy of the pulse-heated battery BT1, step 526. If the voltage of the battery BT1 is not lower than the voltage threshold preset for the initial voltage, the process returns to step 522 and continues to monitor the voltage of the battery BT1. In some embodiments of the present application, the preset voltage value is slightly greater than the initial voltage of the battery BT1.

[0099] Figure 6 1 illustrates a block diagram of a charging device 600 according to another embodiment of the present application. Figure 6As shown, the pulse heating module 104 includes four switch modules Q1-Q4, an inductor L, and a switch K1. Switch K1 is provided on the positive busbar on the input side of the pulse heating module 104. Switch modules Q1 and Q3 are connected in series between the positive and negative busbars of the pulse heating module 104. Switch modules Q2 and Q4 are also connected in series between the positive and negative busbars of the pulse heating module 104. Inductor L is connected between the midpoint between switch modules Q1 and Q3 and the midpoint between switch modules Q2 and Q4. Furthermore, the positive busbar of the DC converter 106 is connected to the positive busbar of the DC source 102 via switch K2.

[0100] If it is determined in step 504 that the heating frequency requirement is greater than or equal to the preset first frequency, the main controller 108 controls switch K1 to close and switch K2 to open, and the pulse heating module 104 heats the battery BT1. If it is determined in step 504 that the heating frequency requirement is less than the preset first frequency, the main controller 108 controls switch K1 to open and switch K2 to close, and the DC converter 106 heats the battery BT1.

[0101] It should be understood that Figure 6 The example shows an exemplary embodiment of the present application. In other embodiments of the present application, the positive bus of the DC converter 106 is directly connected to the positive bus of the DC source 102 without passing through the switch K2. When the heating frequency requirement is greater than or equal to the preset first frequency, the main controller 108 controls the switch K1 to close and controls all the switch modules in the DC converter 106 to disconnect; when the heating frequency requirement is less than the preset first frequency, the main controller 108 controls the switch K1 to disconnect and controls the closing and disconnection of the switch modules in the DC converter 106 to heat the battery BT1.

[0102] During the heating of battery BT1 by pulse heating module 104, at time t1, main controller 108 controls switch modules Q1 and Q4 to close and Q2 and Q3 to disconnect, and battery BT1 stores energy in inductor L; then at time t2, main controller 108 controls switch modules Q1 and Q4 to disconnect and Q2 and Q3 to close, and inductor L discharges to battery BT1; at time t3, the state of switch module at time t2 is maintained, and battery BT1 stores energy in inductor L again; at time t4, main controller 108 controls switch modules Q1 and Q4 to close and Q2 and Q3 to disconnect, and inductor L discharges to battery BT1. It should be understood that the pulse heating cycle can also start from time t3, go through time t4, time t1, and end at time t2. In the embodiment of the present application, in the first cycle of generating pulse current, the first half cycle must first start with battery BT1 storing energy in inductor L, that is, start at time t1 or time t3.

[0103] It should be understood that Figure 6Illustrated is an exemplary embodiment of the present application, except that Figure 6 The pulse heating module 104 may adopt any other topology structure capable of realizing the pulse heating function.

[0104] Figure 7 FIG. 7 illustrates a block diagram of a charging device 700 according to another embodiment of the present application. Figure 7 As shown, the charging device 500 includes multiple pulse heating modules 1041, 1042, ..., 104m connected in parallel, and when the heating frequency is required to be greater than or equal to a preset first frequency, one or more of the multiple pulse heating modules 1041, 1042, ..., 104m heat the battery BT1. In addition, the charging device 700 includes multiple DC converters 1061, 1062, ..., 106n connected in parallel, and when the heating frequency is required to be less than a preset first frequency, one or more of the multiple DC converters 1061, 1062, ..., 106n heat the battery BT1. In addition, the battery BT1 can be charged by one or more of the multiple DC converters 1061, 1062, ..., 106n.

[0105] Figure 8 A flow chart of a battery charging method 800 according to one embodiment of the present application is illustrated. Figure 8 As shown, in step 802, a first message is received, which includes a heating request, a heating frequency requirement, a heating current limit, and the like. Then, in step 804, a determination is made as to whether the received heating frequency requirement is greater than or equal to a preset first frequency. If the heating frequency requirement is greater than or equal to the preset first frequency, the pulse heating module 104 heats the battery BT1, in step 806. If the heating frequency requirement is less than the preset first frequency, the DC converter 106 heats the battery BT1, in step 808. Subsequently, in step 810, a second message is received, which includes a stop heating instruction. In response to the stop heating instruction, heating of the battery BT1 is stopped in step 812. In step 814, a third message is received, which includes a charging instruction, a DC charging voltage limit, a current limit, and the like. In response to the charging instruction, in step 816, the main controller 108 controls the DC source 102 and the DC converter 106 to charge the battery BT1 according to the DC charging voltage limit and current limit. Finally, in step 818, a fourth message is received, which includes a charge termination instruction. In response to the charge end instruction, at step 820 , the main controller 108 controls the DC source 102 and the DC converter 106 to end charging.

[0106] Figures 9a to 9eSchematic diagrams illustrating five topological structures of a bidirectional DC converter in a charging device according to the present application. Figure 9a The LLC resonant DC converter is illustrated. Figure 9b The dual-active-bridge (DAB) DC converter is illustrated. Figure 9c The CLLC resonant DC converter is illustrated. Figure 9d The current-fed dual-active-bridge (CF-DAB) DC converter is illustrated. Figure 9e The bidirectional DC converter in the charging device of the present application can be used as a partial power converter (PPC). Figures 9a to 9e The topologies illustrated in the figure and various variations of these topologies can implement the functions described above.

[0107] Figure 10a and Figure 10b A schematic diagram illustrating the structure of a bidirectional DC converter in a charging device according to the present application is shown. Figure 10a A two-stage LLC bidirectional DC converter 1000a is illustrated. The bus side of the DC converter is connected to a DC source 102. The bus-side capacitor Cdc is connected to a buck-boost circuit, which is then connected to a bidirectional LLC series resonant converter (LLC-SRC). The LLC-SRC is then connected to a battery BT1. The two-stage LLC bidirectional DC converter features two-stage voltage control. The buck-boost circuit can control the duty cycle of switch modules S1 and S2 as needed to boost or buck the voltage. The LLC-SRC further controls the voltage to ensure a constant voltage supplied to the battery. The LLC-SRC utilizes frequency control, with the duty cycle of the upper and lower switch modules M1-M8 in each bridge arm set to 50%. As the system load changes, the system's operating frequency needs to be adjusted. Specifically, when the load increases, the switching frequency of switch modules M1-M8 decreases, and when the load decreases, the switching frequency of switch modules M1-M8 increases. The LLC circuit in the bidirectional LLC-SRC includes capacitor Cr and inductors Lr and Lm. Capacitor Cr and inductor Lr are considered as one part, with their impedance set to Zr, while inductor Lm is considered as the other part, with its impedance set to Zo. When the system load changes, changing the switching frequency of switch modules M1-M4 can change the voltage divider ratio of Zr and Zo, thereby stabilizing the output voltage.

[0108] With the above reference Figure 6The description about the pulse heating module 104 generating the pulse current is similar, for example, Figure 10a During heating of battery BT1 by the two-stage LLC-type bidirectional DC converter 1000a, at time t1, the main controller 108 controls switch modules M5 and M8 to close and M6 and M7 to open, causing battery BT1 to store energy in the secondary winding of the bidirectional LLC-SRC transformer. Then, at time t2, the main controller 108 controls switch modules M5 and M8 to open and M6 and M7 to close, causing the secondary winding of the transformer to discharge energy into battery BT1. At time t3, the switch modules maintain their states from time t2, causing battery BT1 to again store energy in the secondary winding of the transformer. At time t4, the main controller 108 controls switch modules M5 and M8 to close and M6 and M7 to open, causing the secondary winding to discharge energy into battery BT1. The lower the switching frequency of switch modules M5-M8, the greater the current generated in the secondary winding of the transformer, resulting in higher power. It should be understood that the bidirectional LLC-SRC can employ other control strategies suitable for generating pulsed current for battery heating.

[0109] Figure 10b A dual-active bridge DC converter 1000b is illustrated, comprising a U1-side full-bridge circuit, an inductor L1, a transformer T, and a U2-side full-bridge circuit. The DC bus of the U1-side full-bridge circuit is connected to a DC source 102. The inductor L1 and the primary winding of the transformer T are connected in series between the midpoints of the two bridge arms of the U1-side full-bridge circuit. The secondary winding of the transformer T is connected between the midpoints of the two bridge arms of the U2-side full-bridge circuit. The DC bus of the U2-side full-bridge circuit is connected to a battery BT1.

[0110] Figures 11a to 11c Illustrated Figure 10b Waveform diagrams of different modulation strategies of the bidirectional DC converter 1000b. Figure 11a The waveform diagram of the dual-phase-shifting (DPS) modulation strategy of the dual active bridge DC converter is illustrated; Figure 11b The waveform diagram of the extended phase-shifting (EPS) modulation strategy of the dual active bridge DC converter is illustrated; Figure 11c The waveform diagram of the triple-phase-shifting (TPS) modulation strategy of the dual active bridge DC converter is illustrated.

[0111] Corresponding to Figure 11a The waveform shown in Figure 10b The working modes of the dual active bridge DC converter 1000b can be divided into Figures 12a to 12h 8 working states.

[0112] Mode 1 is as follows Figure 12aAs shown, in the t0-t1 stage: before time t0, switches S1 and S4 are disconnected and S2 and S3 are closed, and the current iL on the inductor L1 is negative; at time t0, switches S1 to S4 are closed and S2 and S3 remain closed, VP is 0, and since the current iL is still negative, the current continues to flow through switch S3 and diode D1 or through switch S2 and diode D4; in the full-bridge circuit on the U2 side, switches Q1 and Q4 are disconnected and Q2 and Q3 are closed. Since the current iL is negative, the current on the U2 side feeds energy to the battery BT1 through diodes M2 and M3, and the current iL gradually decreases.

[0113] Mode 2 Figure 12b As shown, in the t1-t1' stage: at t1, the current iL is still less than 0, the switches S2 and S3 are disconnected and S1 and S4 remain closed, the current iL is converted to freewheeling through the diodes D1 and D4, and Vp is equal to U1; the switching state of the full-bridge circuit on the U2 side is the same as in mode 1, and the inductor L1 feeds energy to the battery BT1 on the U2 side and the U1 side at the same time until the current iL drops to zero at t1'.

[0114] Mode 3 Figure 12c As shown, in the t1'-t2 stage: at t1', the current iL changes from negative to positive, the switches S1 and S4 as well as Q2 and Q3 are closed and the current flows through these four switches, the DC source on the U1 side and the battery BT1 on the U2 side simultaneously feed energy to the inductor L1, and the current iL increases rapidly.

[0115] Mode 4 Figure 12d As shown, in the t2-t3 stage: at time t2, switches Q1 and Q4 are closed and Q2 and Q3 remain closed, VS is 0, and the current on the U2 side is continuously flowing through the switch Q2 and the diode M4 or through the switch Q3 and the diode M1; the current iL is positive, and the switching state of the full-bridge circuit on the U1 side is the same as that in mode 3. The DC source on the U1 side feeds energy to the inductor L1, and the current iL increases and the gradient decreases.

[0116] Mode 5 Figure 12e As shown, in the t3-t4 stage: at time t3, switches Q2 and Q3 are disconnected and Q1 and Q4 remain closed, VS is equal to U2, and since the current iL is positive, the current on the U2 side provides energy to the battery BT1 through the diodes M1 and M4; the switching state of the full-bridge circuit on the U1 side is the same as in mode 3, the DC source on the U1 side feeds energy to the inductor L1, and the current iL increases or decreases according to the energy difference between the energy received from the U1 side and the energy provided to the battery BT1.

[0117] Mode 6 Figure 12fAs shown, in the t4-t5' stage: at t4, switches S1 and S4 are disconnected and S2 and S3 remain disconnected, the current iL is positive and converted to continuous flow through diodes D2 and D3, the inductor L1 feeds energy to the DC source on the U1 side, the switching state of the full-bridge circuit on the U2 side is the same as mode 5, the current on the U2 side feeds energy to the battery BT1 through diodes M1 and M4, and the current iL decreases; at t5, switches S2 and S3 are closed and S1 and S4 remain disconnected, the current iL still continuous flow through diodes D2 and D3, the inductor L1 feeds energy to the DC source on the U1 side and the battery BT1 at the same time, and the current iL decreases until the current iL drops to zero at t5'.

[0118] Mode 7 Figure 12g As shown, in the t5'-t6 stage: at t5', the current iL changes from positive to negative, switches S2 and S3 as well as Q1 and Q4 are closed and current flows through these four switches, the DC source on the U1 side and the battery BT1 on the U2 side simultaneously feed energy to the inductor L1, and the current iL increases rapidly.

[0119] Mode 8 Figure 12h As shown, in the t6-t8 stage: at t6, switches Q1 and Q4 are disconnected and Q2 and Q3 remain disconnected. Since the current iL is negative, the current on the U2 side feeds energy to the battery BT1 through the diodes M2 and M3; the switching state of the full-bridge circuit on the U1 side is the same as mode 7, the DC source on the U1 side feeds energy to the inductor L1, and the current iL increases and the gradient decreases; at t7, switches Q2 and Q3 are closed and Q1 and Q4 remain disconnected, and the current on the U2 side still feeds energy to the battery BT1 through the diodes M2 and M3.

[0120] In some embodiments of the present application, when the battery BT1 is heated by the dual active bridge DC converter 1000b, the heating pulse cycle may start from mode 3 or mode 7. In addition, in some embodiments of the present application, the waveform of the heating pulse current of the battery BT1 may be adjusted by adjusting the shift ratio of the full bridge circuit on the U1 side and the full bridge circuit on the U2 side and the voltage of the DC source on the U1 side.

[0121] Similarly, those skilled in the art will Figure 11b and Figure 11c The waveform can also infer the working mode of the extended phase shift modulation strategy and the triple phase shift modulation strategy, which will not be repeated here. It should be understood that, except for Figures 11a to 11c In addition to the modulation strategy illustrated in FIG, the dual active bridge DC converter 1000 b may adopt other control strategies suitable for generating pulse current for heating the battery.

[0122] While the present invention has been described with reference to preferred embodiments, various modifications may be made and equivalent components may be substituted without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner, provided no structural conflicts exist. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A charging device, characterized in that: The charging device comprises: DC source; a bidirectional DC converter connected between the DC source and a charging port of the charging device; a pulse heating module, the pulse heating module being connected in parallel with the bidirectional DC converter; The DC source includes an energy storage device, which is connected to the bidirectional DC converter and the pulse heating module; A controller configured to: When a heating request is received, selecting one of the pulse heating module and the bidirectional DC converter to heat the battery according to whether a heating frequency requirement of the battery is less than a preset first frequency; When the heating frequency requirement is lower than a preset second frequency, pulse energy is exchanged between the energy storage device and the battery to heat the battery; wherein the preset second frequency is lower than the preset first frequency.

2. The charging device according to claim 1, characterized in that The controller is configured to: When the heating frequency requirement is less than a preset first frequency, selecting the bidirectional DC converter to heat the battery; and When the heating frequency requirement is greater than or equal to the preset first frequency, the pulse heating module is selected to heat the battery.

3. The charging device according to claim 1 or 2, characterized in that: The controller is configured to: When the heating frequency requirement is less than a preset second frequency, the bidirectional DC converter is controlled so that energy released by the battery during battery discharge is fed back to the DC source, wherein the preset second frequency is less than the preset first frequency.

4. The charging device according to any one of claims 1 to 3, characterized in that The DC source includes a bidirectional rectifier connected to a power grid, and the controller is configured to: When the heating frequency requirement is less than a preset second frequency, the bidirectional rectifier and the bidirectional DC converter are controlled so that energy released by the battery is fed back to the power grid during battery discharge, wherein the preset second frequency is less than the preset first frequency.

5. The charging device according to any one of claims 1 to 4, characterized in that: The controller is configured to: When the heating frequency requirement is greater than or equal to a preset second frequency and less than the preset first frequency, the bidirectional DC converter is controlled so that energy released by the battery during battery discharge is stored in the energy storage element of the bidirectional DC converter, wherein the preset second frequency is less than the preset first frequency.

6. The charging device according to any one of claims 1 to 5, characterized in that The DC source includes a rectifier connected to a power grid, the charging device is configured to monitor the voltage of the battery, and the controller is configured to: When the voltage of the battery is lower than a preset voltage threshold of the initial voltage of the battery, the rectifier is controlled to supplement the battery, wherein the initial voltage is the voltage when the battery starts to be heated.

7. The charging device according to claim 6, characterized in that When the battery is heated by the bidirectional DC converter, the controller is configured to control the rectifier and the bidirectional DC converter to adjust the balance of charging energy and discharging energy of the pulse heating battery; and When the battery is heated by the pulse heating module, the controller is configured to control the rectifier so that the output voltage of the rectifier is equal to a preset voltage value during the period when the energy storage element of the pulse heating module charges the battery, and the preset voltage value is greater than or equal to the initial voltage of the battery.

8. The charging device according to any one of claims 1 to 7, characterized in that The charging device includes a plurality of bidirectional DC converters connected in parallel with each other, and when the heating frequency requirement is less than the preset first frequency, one or more of the plurality of bidirectional DC converters heats the battery.

9. The charging device according to any one of claims 1 to 8, characterized in that The charging device includes a plurality of pulse heating modules connected in parallel with each other, and when the heating frequency requirement is greater than or equal to the preset first frequency, one or more of the plurality of pulse heating modules heats the battery.

10. A method for heating a battery, characterized in that: The method comprises: receiving a heating request and a heating frequency requirement for the battery; In response to a heating request, and depending on whether the heating frequency requirement is less than a preset first frequency, selecting one of a pulse heating module and a bidirectional DC converter connected between a DC source and the battery to heat the battery; The DC source includes an energy storage device. When the heating frequency requirement is less than a preset second frequency, pulse energy is exchanged between the energy storage device and the battery to heat the battery; wherein the preset second frequency is less than the preset first frequency.

11. The method according to claim 10, characterized in that The method comprises: When the heating frequency requirement is less than a preset first frequency, the bidirectional DC converter heats the battery; and When the heating frequency requirement is greater than or equal to the preset first frequency, the pulse heating module heats the battery.

12. The method according to claim 10 or 11, characterized in that The method comprises: When the heating frequency requirement is less than a preset second frequency, the bidirectional DC converter is controlled so that energy released by the battery during battery discharge is fed back to the DC source, wherein the preset second frequency is less than the preset first frequency.

13. The method according to any one of claims 10 to 12, characterized in that The DC source includes a bidirectional rectifier connected to a power grid, and the method includes: When the heating frequency requirement is less than a preset second frequency, the bidirectional rectifier and the bidirectional DC converter are controlled so that energy released by the battery is fed back to the power grid during battery discharge, wherein the preset second frequency is less than the preset first frequency.

14. The method according to any one of claims 10 to 13, characterized in that The method comprises: When the heating frequency requirement is greater than or equal to a preset second frequency and less than the preset first frequency, the bidirectional DC converter is controlled so that energy released by the battery during battery discharge is stored in the energy storage element of the bidirectional DC converter, wherein the preset second frequency is less than the preset first frequency.

15. The method according to any one of claims 10 to 14, characterized in that The DC source includes a rectifier connected to a power grid, and the method includes: monitoring the voltage of the battery; and When the voltage of the battery is lower than a preset voltage threshold of the initial voltage of the battery, the rectifier is controlled to supplement the battery, wherein the initial voltage is the voltage when the battery starts to be heated.

16. The method according to claim 15, characterized in that The method comprises: When the bidirectional DC converter heats the battery, controlling the rectifier and the bidirectional DC converter to adjust the balance of charging energy and discharging energy of the pulse heating battery; and When the battery is heated by the pulse heating module, the rectifier is controlled so that the output voltage of the rectifier is equal to a preset voltage value during the period when the energy storage element of the pulse heating module charges the battery, and the preset voltage value is greater than or equal to the initial voltage of the battery.

17. The method according to any one of claims 10 to 16, characterized in that A plurality of bidirectional DC converters connected in parallel with each other are connected between the DC source and the battery, and when the heating frequency requirement is less than the preset first frequency, one or more of the plurality of bidirectional DC converters heats the battery.

18. The method according to claim 15 or 16, characterized in that A plurality of pulse heating modules connected in parallel to each other are connected between the rectifier and the battery, and when the heating frequency requirement is greater than or equal to the preset first frequency, one or more of the plurality of pulse heating modules heats the battery.

19. A storage medium, characterized in that The storage medium stores instructions, which, when executed by a computing device, enable the computing device to implement the method for heating a battery according to any one of claims 10 to 18.

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