Charging circuit, charging system and vehicle

Abstract

The utility model discloses a charging circuit, a charging system and a vehicle, and belongs to the technical field of charging. The input side of the charging circuit is used for connecting an electric output system, the output side of the charging circuit is used for connecting a battery system, and the charging circuit comprises a first voltage conversion circuit connected between the input side and the output side; in the charging handshake stage, the first voltage conversion circuit is configured to boost the voltage of the output side. After the battery system is connected with the electricity output system, in the charging handshake stage, the voltage output by the battery system is boosted through the first voltage conversion circuit, and the rechargeable voltage fed back to the electricity output system is boosted, so that the electricity output system can output according to the boosted rechargeable voltage; charging among different voltage platforms is realized, and the output power of the electric output system is improved.

Description

Technical Field

[0001] This application belongs to the field of charging technology, and in particular relates to a charging circuit, a charging system and a vehicle. Background Technology

[0002] Electric vehicle battery systems typically have multiple voltage platforms, such as a coexistence of low-voltage 400V and high-voltage 800V. Correspondingly, charging systems (such as charging stations) are also equipped with multiple voltage platforms. This can easily lead to voltage mismatch issues during charging, resulting in slow charging or even failure to charge. Utility Model Content

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a charging circuit, a charging system, and a vehicle that achieves charging between different voltage platforms and improves the output power of the electric output system by increasing the rechargeable voltage fed back from the battery system to the electric output system.

[0004] In a first aspect, this application provides a charging circuit, wherein the input side of the charging circuit is used to connect to an electrical output system, the output side of the charging circuit is used to connect to a battery system, and the charging circuit includes a first voltage conversion circuit connected between the input side and the output side.

[0005] During the charging handshake phase, the first voltage conversion circuit is configured to boost the voltage on the output side.

[0006] In some examples, the first voltage conversion circuit includes a unidirectional conducting device, the input of which is electrically connected to the input side, and the output of which is electrically connected to the output side.

[0007] In some examples, the unidirectional conducting device includes a first diode, and the first voltage conversion circuit further includes:

[0008] The first switch has its first terminal electrically connected to the positive terminal of the output side, its second terminal electrically connected to the cathode of the first diode, and the anode of the first diode electrically connected to the negative terminal of the input side.

[0009] The second switch has its first terminal electrically connected to the negative terminal of the output side and its second terminal electrically connected to the positive terminal of the input side.

[0010] The first inductor has its first end electrically connected to the first end of the first switch, and its second end electrically connected to the second end of the second switch.

[0011] The first capacitor has its first terminal electrically connected to the anode of the first diode, and its second terminal electrically connected to the second terminal of the second switch.

[0012] In some examples, the charging circuit also includes a second voltage conversion circuit connected between the input side and the output side;

[0013] During the charging and transmission phase, the second voltage conversion circuit is configured to step down the voltage on the input side.

[0014] In some examples, the second voltage conversion circuit includes:

[0015] The third switch, the first end of the third switch is electrically connected to the positive terminal of the input side;

[0016] The fourth switch has its first terminal electrically connected to the negative terminal of the input side and its second terminal electrically connected to the positive terminal of the output side.

[0017] The cathode of the second diode is electrically connected to the second terminal of the second switch, and the anode of the second diode is electrically connected to the negative terminal of the output side.

[0018] The second inductor has its first end electrically connected to the second end of the second switch, and its second end is electrically connected to the second end of the fourth switch.

[0019] The second capacitor has its first terminal electrically connected to the anode of the second diode, and its second terminal electrically connected to the second terminal of the fourth switch.

[0020] In some examples, during the charging handshake phase, the first voltage conversion circuit is configured to boost the voltage on the input side to the maximum output voltage of the electrical output system.

[0021] Secondly, this application provides a charging system, including an electrical output system, a battery system, and a charging circuit according to the aforementioned method, wherein the input side of the charging circuit is electrically connected to the electrical output system, and the output side of the charging circuit is electrically connected to the battery system.

[0022] In some examples, the electrical output system includes a voltage detection unit that is electrically connected to the input side of the charging circuit.

[0023] In some examples, the output power of the electrical output system is equal to the maximum input power of the battery system.

[0024] Thirdly, this application provides a vehicle including a battery and a charging circuit according to the foregoing, wherein the output side of the charging circuit is electrically connected to the battery pack and the input side of the charging circuit is used to connect to a charging pile.

[0025] According to the charging circuit, charging system, and vehicle of this application, after the battery system is connected to the electric output system, during the charging handshake stage, the voltage output by the battery system is boosted by the first voltage conversion circuit, thereby increasing the rechargeable voltage fed back to the electric output system. This enables the electric output system to output according to the boosted rechargeable voltage, realizing charging between different voltage platforms and improving the output power of the electric output system.

[0026] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0027] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0028] Figure 1 This is a schematic diagram of the charging system provided in an embodiment of this application;

[0029] Figure 2 This is one of the structural schematic diagrams of the charging circuit provided in the embodiments of this application;

[0030] Figure 3 This is a second schematic diagram of the charging circuit provided in the embodiments of this application;

[0031] Figure 4 This is the third schematic diagram of the charging circuit provided in the embodiments of this application.

[0032] Figure label:

[0033] Charging circuit 100, first voltage conversion circuit 110, second voltage conversion circuit 120, power output system 200, charging pile 210, voltage detection unit 220, battery system 300, battery pack 310, first to fourth switches K1 to K4, first to second diodes D1 to D2, first to second inductors L1 to L2, first to second capacitors C1 to C2, transmission lines E1 and E2, detection points A, B, C, and D. Detailed Implementation

[0034] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0035] In the following description, a "circuit" refers to a conductive loop consisting of at least one element or sub-circuit connected by an electrical or electromagnetic link. When an element or circuit is said to be "coupled to" or "connected to" another element, or when an element / circuit is said to be "coupled at" or "connected at" two nodes, it can be directly coupled to or connected to the other element, or there may be intermediate elements. The connection between elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there are no intermediate elements between them.

[0036] In the description, the terms "first," "second," etc., are used to distinguish similar objects, not to describe a specific order or sequence. It should be understood that such numerical descriptors can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class, not limited in number; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0037] Furthermore, the use of terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0038] Taking electric vehicle charging systems as an example, wireless charging may occur when the voltage platforms of the electric vehicle's battery system and the charging station are mismatched. Alternatively, if the battery system's voltage is lower than the charging station's voltage (for example, when the battery system is at a low charge level, the total voltage is lower), the charging station often outputs the lower voltage of the battery system. In this case, the charging current may also be less than the battery system's maximum charging current, resulting in a slower charging speed.

[0039] As an example, suppose the charging pile has a maximum output power of 150kW, a maximum output voltage of 600V, and a maximum output current of 250A. The electric vehicle's battery system has a maximum charging power of 140kW, a maximum charging voltage of 400V, and a maximum charging current of 350A. When the electric vehicle is connected to the charging pile and charging begins, since the charging pile detects the battery system's maximum charging voltage as 400V, its actual output voltage is 400V, and its actual output current is 250A. Therefore, the actual output power is 100kW, and the battery system's actual input is the same as the charging pile's actual output. This shows that the battery system is not reaching its maximum charging power, and the charging speed cannot reach its fastest rate.

[0040] To address the aforementioned technical problems, this application proposes a charging circuit, a charging system, and a vehicle. After the battery system is connected to the electric output system, during the charging handshake phase, the voltage output by the battery system is boosted through a first voltage conversion circuit, increasing the rechargeable voltage fed back to the electric output system. This allows the electric output system to output according to the boosted rechargeable voltage, enabling charging between different voltage platforms and improving the output power of the electric output system.

[0041] The charging circuit, charging system, and vehicle of embodiments of this application are described below with reference to the accompanying drawings.

[0042] Reference Figure 1 , Figure 1 An architecture of a charging system is illustrated, and one embodiment of this application proposes a charging system. In this embodiment, the charging system includes a charging circuit 100, an electrical output system 200, and a battery system 300. The input side of the charging circuit 100 is electrically connected to the electrical output system 200, and the output side of the charging circuit 100 is electrically connected to the battery system 300. During the charging handshake phase, the charging circuit 100 boosts the actual voltage of the battery system 300 and feeds it back to the electrical output system 200, which then outputs a voltage based on the boosted voltage.

[0043] As an example, the power output system 200 can be a charging pile 210, and the battery system 300 can be a battery pack 310 inside an electric vehicle. This example will be used for the following description. Of course, the charging system can be other types of systems, and this embodiment is not limited to them.

[0044] Understandably, when charging begins, the charging station 210 needs to detect the voltage of the battery pack 310 in order to output the corresponding voltage. In the aforementioned related technology, the charging station 210 detects that the voltage of the battery pack 310 is 400V, so it outputs 400V.

[0045] In this embodiment, the voltage detected by the charging pile 210 is the voltage of the battery pack 310 after being boosted by the charging circuit 100, which is greater than 400V, such as 450V, 500V, 550V, or 600V. Therefore, the charging pile 210 can output a voltage greater than 400V, thereby improving the charging power.

[0046] In some examples, the electrical output system 200 includes a voltage detection unit 220 that is electrically connected to the input side of the charging circuit 100.

[0047] The charging pile 210 may be equipped with a voltage detection unit 220 to detect the rechargeable voltage of the object being charged. The charging circuit 100 may be integrated into the electric vehicle, and the detection end of the voltage detection unit 220 may be integrated into the charging transmission device (such as a charging gun). After the charging transmission device is connected to the electric vehicle, the voltage detection unit 220 detects the voltage of the connection node. In the electric vehicle, this connection node is located on the side of the charging circuit 100 away from the battery pack 310, so that the voltage detected by the voltage detection unit 220 is the voltage after the output voltage of the battery pack 310 is boosted by the charging circuit 100.

[0048] In some examples, the output power of the electrical output system 200 is equal to the maximum input power of the battery system 300.

[0049] In this example, the charging station 210 outputs the voltage based on the boosted voltage of the battery pack 310 after being stepped up by the charging circuit 100; simultaneously, the output current corresponding to the determined voltage is determined based on the maximum input power of the battery pack 310. Therefore, the charging power received by the battery pack 310 reaches its maximum value, resulting in a faster charging speed.

[0050] Of course, in other examples, the output power of the electrical output system 200 may be less than the maximum input power of the battery system 300. The electrical output system 200 can adjust the actual output current according to actual needs to meet the corresponding charging conditions. Generally, since the actual output voltage of the electrical output system 200 is greater than the maximum output voltage of the battery system 300, even if the output power of the electrical output system 200 cannot be less than the maximum input power of the battery system 300, it can still ensure that it can output the maximum output power allowed by the operating conditions, which can also improve the charging speed to a certain extent.

[0051] Reference Figure 2 , Figure 2 The structure of a charging circuit 100 is shown. One embodiment of this application proposes a charging circuit 100. Taking the charging circuit 100 connected to a charging pile 210 and a battery pack 310 as an example, the structure and principle of the charging circuit 100 are explained.

[0052] In this embodiment, the input side of the charging circuit 100 is electrically connected to the charging pile 210, and the output side of the charging circuit 100 is electrically connected to the battery pack 310. The charging circuit 100 includes a first voltage conversion circuit 110 connected between the input side and the output side. During the charging handshake phase, the first voltage conversion circuit 110 boosts the voltage on the output side.

[0053] The charging handshake phase mainly completes the identification between the power output system 200 and the battery system 300, preparing for formal charging. After the charging pile 210 establishes a power connection with the battery pack 310 through the charging circuit 100, the charging pile 210 can communicate with the control unit (such as the power management unit of the electric vehicle) using CAN messages to confirm that both parties are ready.

[0054] During the charging handshake phase, the charging station 210 needs to determine the output voltage. In this embodiment, the output side of the charging circuit 100 has a voltage detection node. The charging station 210 detects this voltage detection node, takes the detected voltage as the acceptable voltage for the battery pack 310, and outputs the battery according to this voltage. When the battery pack 310 discharges, the charging circuit 100 boosts its voltage so that the voltage detected by the charging station 210 is greater than the actual output voltage of the battery pack 310. For example, if the actual output voltage of the battery pack 310 is 400V, the voltage of the voltage detection node can be 450V, 500V, 550V, or 600V, etc.

[0055] In some examples, during the charging handshake phase, the first voltage conversion circuit 110 is configured to boost the voltage on the input side to the maximum output voltage of the electrical output system 200.

[0056] Understandably, when the input voltage is boosted to the maximum output voltage of the charging pile 210, the charging pile 210 will output according to its maximum output voltage, and its actual output power will be allowed to reach its maximum value. Therefore, the charging pile 210 has a maximum output power range, which is beneficial for improving charging speed. Of course, the actual output power of the charging pile 210 should ideally not exceed the maximum input power of the battery pack 310.

[0057] The charging pile 210 determines the actual output voltage based on the voltage of the voltage detection node, and can determine the corresponding output current based on the input power of the battery pack 310, as detailed above. By increasing the rechargeable voltage fed back from the battery pack 310 to the charging pile 210, the charging pile 210 outputs according to the boosted rechargeable voltage, realizing charging between different voltage platforms and ensuring high power output of the charging pile 210.

[0058] It should be noted that after the charging handshake phase ends, the first voltage conversion circuit 110 no longer boosts the voltage on the output side to avoid interfering with normal charging.

[0059] In some examples, the first voltage conversion circuit 110 may include a unidirectional conducting device, the input of which is electrically connected to the input side of the charging circuit 100, and the output of which is electrically connected to the output side of the charging circuit 100.

[0060] Since the unidirectional conducting device is reverse-biased within the first voltage conversion circuit 110, when boosting the discharge voltage of the battery pack 310, it blocks the discharge current from flowing to the input side of the charging circuit 100, making it difficult for the discharge current to flow into the charging pile 210, thereby improving the safety of the charging circuit 100.

[0061] As an example, the unidirectional conducting device can be a diode, with the cathode of the diode electrically connected to the output side of the charging circuit 100 and the anode of the diode electrically connected to the input side of the charging circuit 100.

[0062] Reference Figure 3 , Figure 3 The structure of a charging circuit 100 is shown, and one embodiment of this application proposes a charging circuit 100. In this embodiment, the charging circuit 100 further includes a second voltage conversion circuit 120 connected between the input side and the output side; during the charging transfer phase, the second voltage conversion circuit 120 is configured to step down the voltage on the input side.

[0063] The charging transmission stage refers to the process where the charging pile 210 outputs electrical energy, and the charging circuit 100 transmits the electrical energy to the battery pack 310 to charge the battery pack 310. The second voltage conversion circuit 120 has a voltage reduction capability, and the voltage transmitted to the battery pack 310 can be greater than or equal to the voltage of the battery pack 310. For example, if the voltage of the battery pack 310 is 400V and the output voltage of the charging pile 210 is 600V, the voltage after voltage reduction by the second voltage conversion circuit 120 can be 550V, 500V, 450V, or 400V, etc., which can be set according to requirements. This embodiment does not impose any limitations on this.

[0064] Since the output voltage of the charging pile 210 is higher than that of the battery pack 310, the second voltage conversion circuit 120 reduces the output voltage of the charging pile 210 to balance the voltage and reduce potential charging hazards. Furthermore, while the charging pile 210 maintains a constant power output, the second voltage conversion circuit 120 can increase the current while reducing the voltage, thereby improving the charging speed.

[0065] Reference Figure 4 , Figure 4A specific circuit structure of a charging circuit 100 is shown. One embodiment of this application proposes a charging circuit 100. In this embodiment, both the first voltage conversion circuit 110 and the second voltage conversion circuit 120 can be Buck-Boost type step-up / step-down circuits. Specifically, the input side of the step-up / step-down circuit of the first voltage conversion circuit 110 is connected to the battery pack 310, and the output side is connected to the charging pile 210. Similarly, the input side of the step-up / step-down circuit of the second voltage conversion circuit 120 is connected to the charging pile 210, and the output side is connected to the battery pack 310.

[0066] As an example, the first voltage conversion circuit 110 includes a first switch K1, a second switch K2, a first diode D1, a first inductor L1, and a first capacitor C1. The first terminal of the first switch K1 is electrically connected to the positive terminal of the output side, the second terminal of the first switch K1 is electrically connected to the cathode of the first diode D1, and the anode of the first diode D1 is electrically connected to the negative terminal of the input side. The first terminal of the second switch K2 is electrically connected to the negative terminal of the output side, and the second terminal of the second switch K2 is electrically connected to the positive terminal of the input side. The first terminal of the first inductor L1 is electrically connected to the first terminal of the first switch K1, and the second terminal of the first inductor L1 is electrically connected to the second terminal of the second switch K2. The first terminal of the first capacitor C1 is electrically connected to the anode of the first diode D1, and the second terminal of the first capacitor C1 is electrically connected to the second terminal of the second switch K2.

[0067] The charging circuit includes two transmission lines E1 and E2. One end of transmission line E1 is connected to the positive terminal of the battery pack 310, and the other end is connected to the negative terminal of the charging pile 210. One end of transmission line E2 is connected to the negative terminal of the battery pack 310, and the other end is connected to the negative terminal of the charging pile 210. Due to the polarity reversal effect of the buck-boost circuit, the two ends of transmission lines E1 and E2 are connected to different polarities.

[0068] The first switch K1 and the first diode D1 can be installed on transmission line E1, and the second switch K2 can be installed on transmission line E2. The first diode D1 can be a high-voltage diode to prevent the battery from actually discharging to the outside.

[0069] During the charging handshake phase, the second switch K2 remains on, and the first switch K1 operates with a set duty cycle D1. The voltage Vab at detection point AB is Vcd*(D1 / (1-D1)). This duty cycle D1 is greater than 0.5 to achieve voltage boost, and its specific value is set according to requirements. During the charging transmission phase, both the first switch K1 and the second switch K2 are in the off state.

[0070] As an example, the second voltage conversion circuit 120 includes a third switch K3, a fourth switch K4, a second diode D2, a second inductor L2, and a second capacitor C2. The first terminal of the third switch K2 is electrically connected to the positive terminal of the input side; the first terminal of the fourth switch K4 is electrically connected to the negative terminal of the input side, and the second terminal of the fourth switch K4 is electrically connected to the positive terminal of the output side; the cathode of the second diode D2 is electrically connected to the second terminal of the second switch K2, and the anode of the second diode D2 is electrically connected to the negative terminal of the output side; the first terminal of the second inductor L2 is electrically connected to the second terminal of the second switch K2, and the second terminal of the second inductor L2 is electrically connected to the second terminal of the fourth switch K4; the first terminal of the second capacitor C2 is electrically connected to the anode of the second diode D2, and the second terminal of the second capacitor C2 is electrically connected to the second terminal of the fourth switch K4.

[0071] The third switch K3 and the second diode D2 can be located on transmission line E2, and the fourth switch K4 can be located on transmission line E1. During the charging transmission phase, the fourth switch K4 remains on, and the third switch K3 operates with a set duty cycle D2. The voltage Vcd at the detection point CD is Vab*(D2 / (1-D2)). This duty cycle D2 is greater than 0.5 to achieve voltage boost, and its specific value can be set according to requirements. During the charging handshake phase, both the third switch K3 and the fourth switch K4 are in the off state.

[0072] The first switch K1, the second switch K2, the third switch K3, and the fourth switch K4 can all be MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) or IGBTs (Insulated-Gate Bipolar Transistors). Taking a MOSFET as an example, the first and second terminals of the switch can be the source or the drain; taking an IGBT as an example, the first and second terminals of the switch can be the collector or the emitter.

[0073] In this embodiment, the first voltage conversion circuit 110 and the second voltage conversion circuit 120 are arranged in parallel with independent lines. In other examples, the first voltage conversion circuit 110 and the second voltage conversion circuit 120 may also be transformed from circuits provided with the same line, for example, by using a switch to control the access of components, so that the circuit switches between the topology corresponding to the first voltage conversion circuit 110 and the topology corresponding to the second voltage conversion circuit 120.

[0074] One embodiment of this application also provides a vehicle, which includes a battery pack 310 and a charging circuit 100 as described above, with a first side of the charging circuit 100 electrically connected to the battery pack 310. Of course, the vehicle also has its main structure, which will not be described in detail here. The specific structure and principle of the charging circuit 100 can be referred to the foregoing, and will not be repeated here in this embodiment.

[0075] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A charging circuit, characterized in that, The input side of the charging circuit is used to connect to the electrical output system, and the output side of the charging circuit is used to connect to the battery system. The charging circuit includes a first voltage conversion circuit connected between the input side and the output side. During the charging handshake phase, the first voltage conversion circuit is configured to boost the voltage on the output side.

2. The charging circuit according to claim 1, characterized in that, The first voltage conversion circuit includes a unidirectional conducting device, the input terminal of which is electrically connected to the input side, and the output terminal of which is electrically connected to the output side.

3. The charging circuit according to claim 2, characterized in that, The unidirectional conducting device includes a first diode, and the first voltage conversion circuit further includes: A first switch, wherein a first end of the first switch is electrically connected to the positive terminal of the output side, a second end of the first switch is electrically connected to the cathode of the first diode, and the anode of the first diode is electrically connected to the negative terminal of the input side. The second switch has its first end electrically connected to the negative terminal of the output side and its second end electrically connected to the positive terminal of the input side. A first inductor, wherein a first end of the first inductor is electrically connected to a first end of the first switch, and a second end of the first inductor is electrically connected to a second end of the second switch; A first capacitor, the first end of which is electrically connected to the anode of the first diode, and the second end of which is electrically connected to the second end of the second switch.

4. The charging circuit according to any one of claims 1-3, characterized in that, The charging circuit further includes a second voltage conversion circuit connected between the input side and the output side; During the charging transmission phase, the second voltage conversion circuit is configured to step down the voltage on the input side.

5. The charging circuit according to claim 4, characterized in that, The second voltage conversion circuit includes: The third switch, the first end of which is electrically connected to the positive terminal of the input side; The fourth switch has its first end electrically connected to the negative terminal of the input side and its second end electrically connected to the positive terminal of the output side. The second diode has its cathode electrically connected to the second terminal of the second switch, and its anode electrically connected to the negative terminal of the output side. The second inductor, the first end of the second inductor is electrically connected to the second end of the second switch, and the second end of the second inductor is electrically connected to the second end of the fourth switch; The second capacitor has its first terminal electrically connected to the anode of the second diode, and its second terminal electrically connected to the second terminal of the fourth switch.

6. The charging circuit according to any one of claims 1-5, characterized in that, During the charging handshake phase, the first voltage conversion circuit is configured to boost the voltage on the input side to the maximum output voltage of the electrical output system.

7. A charging system, characterized in that, It includes an electrical output system, a battery system, and a charging circuit according to any one of claims 1-6, wherein the input side of the charging circuit is electrically connected to the electrical output system, and the output side of the charging circuit is electrically connected to the battery system.

8. The charging system according to claim 7, characterized in that, The electrical output system includes a voltage detection unit, which is electrically connected to the input side of the charging circuit.

9. The charging system according to claim 7 or 8, characterized in that, The output power of the electrical output system is equal to the maximum input power of the battery system.

10. A vehicle, characterized in that, The battery includes a charging circuit according to any one of claims 1-6, wherein the output side of the charging circuit is electrically connected to the battery pack, and the input side of the charging circuit is used to connect to a charging pile.

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