Battery pack charging circuit and electric equipment

Abstract

The utility model provides a battery pack charging circuit and electric equipment. The battery pack charging circuit comprises a first anode charging terminal, a first cathode charging terminal, a charging capacitor and a first contactor. The first anode charging terminal is used for connecting a battery pack anode terminal to form a first anode circuit, and the first cathode charging terminal is used for connecting a battery pack cathode terminal to form a first cathode circuit; one end of the charging capacitor is electrically connected with the first positive electrode circuit, and the other end of the charging capacitor is electrically connected with the first negative electrode circuit; the first contactor is connected with the charging capacitor in series and located between the first positive electrode circuit and the first negative electrode circuit, so that large current can be prevented from flowing through the first contactor when the direct-current boost charging port is used for charging, the current flowing through the first contactor is greatly reduced, the size of the first contactor is reduced, the arrangement space on a whole vehicle is saved, and the service life of the whole vehicle is prolonged. And the occupied power distribution space of the whole vehicle is saved.

Description

Technical Field

[0001] The utility model relates to the technical field of electric vehicle charging, in particular to a battery pack charging circuit and electrical equipment. Background Art

[0002] At present, the DC boost charging method has been gradually promoted in the electric vehicle charging market due to its high charging power. However, this charging method still has certain safety hazards. When the charging gun is charging, the cover of the charging port is open, and people may touch the charging terminals in the charging port. Especially when the whole vehicle has a leakage, if a person touches the charging terminal and the body ground at the same time, the energy stored in the battery pack will be discharged through the human body, causing electric shock to the person, which seriously threatens life safety.

[0003] In order to avoid safety accidents, in the prior art, an anti-electric shock contactor is added to the energy discharge circuit formed between the battery pack and the human body to form a protection circuit to prevent people from electric shock. However, when charging using a DC boost charging port, the current flowing through the anti-electric shock contactor is relatively large, so it is necessary to select an anti-electric shock contactor with a larger rated current, which easily occupies excessive power distribution space in the vehicle. Utility Model Content

[0004] In view of this, the utility model provides a battery pack charging circuit and an electrical device to at least solve the problem in the prior art that the battery pack easily occupies excessive vehicle power distribution space when charging.

[0005] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0006] The utility model provides a battery pack charging circuit, comprising a first positive charging terminal, a first negative charging terminal, a charging capacitor and a first contactor;

[0007] The first positive charging terminal is used to connect the positive terminal of the battery pack to form a first positive circuit, and the first negative charging terminal is used to connect the negative terminal of the battery pack to form a first negative circuit;

[0008] One end of the charging capacitor is electrically connected to the first positive circuit, and the other end of the charging capacitor is electrically connected to the first negative circuit; the first contactor is connected in series with the charging capacitor and is located between the first positive circuit and the first negative circuit.

[0009] Optionally, the first contactor is connected between the charging capacitor and the first positive circuit, or the first contactor is connected between the charging capacitor and the first negative circuit.

[0010] Optionally, the charging capacitor includes a first electrode and a second electrode, the first electrode is electrically connected to the first positive charging terminal, and the second electrode is electrically connected to the first negative charging terminal.

[0011] Optionally, a pressure relief resistor is further included; one end of the pressure relief resistor is electrically connected to the first electrode, and the other end of the pressure relief resistor is electrically connected to the second electrode.

[0012] Optionally, one end of the first contactor is electrically connected to the voltage relief resistor, and the other end of the first contactor is electrically connected to the first positive charging terminal; or, one end of the first contactor is electrically connected to the voltage relief resistor, and the other end of the first contactor is electrically connected to the first negative charging terminal.

[0013] Optionally, one end of the first contactor is electrically connected to the pressure relief resistor, and the other end of the first contactor is electrically connected to the first electrode; or, one end of the first contactor is electrically connected to the pressure relief resistor, and the other end of the first contactor is electrically connected to the second electrode.

[0014] Optionally, a boost module is also included; the boost module is connected between the charging capacitor and the battery pack, and is used to boost the voltage of the battery pack charging circuit.

[0015] Optionally, a second contactor is further included; the second contactor is connected between the boost module and the charging capacitor.

[0016] Optionally, a third contactor is further included; the third contactor is connected to the first negative circuit and is used to control the on and off of the first negative circuit.

[0017] Optionally, it also includes a second positive charging terminal and a second negative charging terminal; the second positive charging terminal is used to connect the positive terminal of the battery pack to form a second positive circuit, and the second negative charging terminal is used to connect the negative terminal of the battery pack to form a second negative circuit.

[0018] The utility model also provides an electrical device, comprising a battery pack and the battery pack charging circuit as described in any one of the above items, wherein the battery pack is electrically connected to the battery pack charging circuit.

[0019] Compared with the prior art, the battery pack charging circuit and the electrical equipment described in the utility model have the following advantages:

[0020] The battery pack charging circuit of the utility model arranges the first contactor between the first positive circuit and the first negative circuit, thereby effectively preventing the large current from flowing through the first contactor when charging at the DC boost charging port, avoiding sintering of the first contactor, and greatly reducing the current flowing through the first contactor. The battery pack charging circuit of the embodiment of the utility model can select a first contactor with a smaller rated current, thereby reducing the volume of the first contactor, helping to save the layout space of the battery pack charging circuit on the whole vehicle, and also helping to save the power distribution space occupied by the battery pack charging circuit on the whole vehicle.

[0021] The electrical equipment of the present invention has the same or similar advantages as the prior art and the aforementioned battery pack charging circuit, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0023] Figure 1 It is a structural schematic diagram of a battery pack charging circuit in an embodiment of the utility model;

[0024] Figure 2 It is a structural schematic diagram of another battery pack charging circuit in an embodiment of the utility model;

[0025] Figure 3 It is a circuit diagram of a battery pack charging circuit in an embodiment of the utility model;

[0026] Figure 4 It is a circuit diagram of another battery pack charging circuit in an embodiment of the utility model. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0028] The terms "first", "second", etc. in the specification and claims of the present utility model are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the utility model can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0029] It should be understood that the reference to "some embodiments" throughout the specification means that specific features, structures or characteristics related to the embodiments are included in at least one embodiment of the utility model. Therefore, the "in some embodiments" appearing in various places throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner.

[0030] The following describes in detail a battery pack charging circuit and an electrical device provided by the utility model by listing specific embodiments.

[0031] Reference Figures 1 to 3 The utility model provides a battery pack charging circuit, including a first positive charging terminal 11, a first negative charging terminal 12, a charging capacitor 3 and a first contactor 4; the first positive charging terminal 11 is used to connect the positive terminal 21 of the battery pack 2 to form a first positive circuit, and the first negative charging terminal 12 is used to connect the negative terminal 22 of the battery pack 2 to form a first negative circuit; one end of the charging capacitor is electrically connected to the first positive circuit, and the other end of the charging capacitor is electrically connected to the first negative circuit; the first contactor 4 is connected in series with the charging capacitor 3 and is located between the first positive circuit and the first negative circuit.

[0032] Specifically, the battery pack charging circuit of the embodiment of the utility model is used to charge the battery pack 2. The battery pack 2 includes a positive terminal and a negative terminal. The first positive charging terminal 11 of the battery pack charging circuit is electrically connected to the positive terminal 21 of the battery pack 2 to form a first positive circuit. The first negative charging terminal 12 of the battery pack charging circuit is electrically connected to the negative terminal 22 of the battery pack 2 to form a first negative circuit. The first positive circuit and the first negative circuit together form a charging circuit, and the battery pack 2 can be charged through the charging circuit. In some implementation scenarios, the battery pack 2 is arranged in an electric vehicle to provide power output for the electric vehicle. In this case, the first positive charging terminal 11 and the first negative charging terminal 12 of the battery pack charging circuit are arranged on the electric vehicle to form a charging port 1 of the electric vehicle. The charging port 1 is usually provided with a cover to cover the charging port 1 when the charging port 1 is not in use, so as to prevent external dust, water vapor, etc. from entering the charging port 1 and affecting the conductive properties of the first positive charging terminal 11 and the first negative charging terminal 12.

[0033] The charging of electric vehicles usually relies on a charging gun. When charging, open the cover of the charging port 1, insert the charging gun into the charging port 1 and electrically connect it to the first positive charging terminal 11 and the first negative charging terminal 12 respectively, so as to charge the battery pack 2 inside the vehicle. At present, most electric vehicles have one or two charging ports, each of which can be connected to a charging gun. If there are two charging ports, dual-gun charging can be achieved, greatly improving the charging efficiency of the battery pack 2. Among them, the two charging ports usually include a DC boost charging port, such as Figure 2 and Figure 3 As shown, the battery pack charging circuit corresponding to the DC boost charging port includes a charging capacitor 3 and a boost module 5, one end of the charging capacitor 3 is electrically connected to the first positive circuit, and the other end is electrically connected to the first negative circuit, the boost module 5 is connected between the charging capacitor 3 and the battery pack 2, and the boost module 5 includes a control switch ( Figure 3 Q1 to Q6 in the figure) and inductor ( Figure 3In the embodiment of the present invention, the inductor is used to store electric energy, and the control switch is used to control the on / off of the circuit between the inductor and the charging port 1. When the control switches Q4, Q5, and Q6 are turned on, the corresponding inductor starts to store electric energy, and then when the control switches Q1, Q2, and Q3 are turned on, the charging port 1 and the inductor discharge the battery pack 2 at the same time, thereby achieving boost charging for the battery pack 2. Exemplarily, in some implementation scenarios, if the output voltage of the charging gun is 500V, and the voltage required for charging the battery pack is 600V, in this case, the battery pack needs to be charged through the DC boost charging port, and the voltage output to the battery pack 2 is made to reach 600V or above through the boost module 5 to meet the charging requirements of the battery pack. In the embodiment of the utility model, the boost module 5 can reuse the drive motor of the whole vehicle to control the design cost of the battery pack charging circuit.

[0034] However, when the cover of the DC boost charging port is opened, people may touch the first positive charging terminal 11 in the DC boost charging port and the vehicle body ground at the same time. Especially when the whole vehicle is leaking electricity, the voltage across the Y capacitor of the battery pack 2 is relatively high. If the user touches the first positive charging terminal 11 and the vehicle body ground at the same time, the voltage of the battery pack 2 to the ground is instantly loaded to the two ends of the charging capacitor 3, causing the charging capacitor 3 to short-circuit. At this time, the energy stored in the Y capacitor is discharged through the human body, causing the risk of electric shock to people, posing a serious safety hazard. Among them, the Y capacitor is a kind of safety capacitor, usually made of high-voltage ceramic chips. Each battery pack charging circuit usually includes two Y capacitors. The two Y capacitors are respectively connected between the positive and negative power lines and the ground line of the battery pack 2 to filter out high-order harmonics, prevent interference, and improve the output voltage quality. The vehicle body ground refers to the metal parts of the vehicle body exposed to the outside, including the frame shell, etc. Generally, when the electric vehicle is powered on or the electric vehicle is charged using a charging gun, a person may touch the first positive charging terminal 11 in the DC boost charging port 1 and the vehicle body ground at the same time, which may easily cause an electric shock accident.

[0035] In order to avoid electric shock accidents, the battery pack charging circuit of the embodiment of the utility model also includes a first contactor 4, which is connected in series with the charging capacitor 3. The first contactor 4 can control the on and off of the branch where the charging capacitor 3 is located. When a person accidentally touches the first positive charging terminal 11 and the vehicle body ground, the branch where the charging capacitor 3 is located can be cut off in time, thereby cutting off the energy discharge circuit formed between the battery pack 2 and the human body to prevent electric shock accidents. At the same time, since the large current when the DC boost charging port is charging flows through the first positive circuit between the first positive charging terminal 11 and the positive terminal 21 of the battery pack 2 and the first negative circuit between the first negative charging terminal 12 and the negative terminal 22 of the battery pack 2, the first contactor 4 is arranged between the first positive circuit and the first negative circuit in the embodiment of the utility model, thereby effectively avoiding the large current when the DC boost charging port 1 is charging from flowing through the first contactor 4, avoiding sintering of the first contactor 4, and greatly reducing the current flowing through the first contactor 4, so that the battery pack charging circuit of the embodiment of the utility model can select the first contactor 4 with a smaller rated current, reducing the volume of the first contactor 4, which helps to save the layout space of the battery pack charging circuit on the whole vehicle, and also helps to save the power distribution space occupied by the battery pack charging circuit of the whole vehicle.

[0036] The charging capacitor 3 includes a first electrode and a second electrode, wherein the first electrode is electrically connected to the first positive charging terminal 11, and the second electrode is electrically connected to the first negative charging terminal 12. Figure 3 A circuit diagram of a battery pack charging circuit in an embodiment of the utility model is shown. Figure 3 As shown, the battery pack charging circuit includes a first positive charging terminal, a first negative charging terminal, a charging capacitor C1 and a first contactor KM1; the first positive charging terminal and the first negative charging terminal form a charging port 1, the first positive charging terminal is used to connect the positive terminal of the battery pack to form a first positive circuit L1, and the first negative charging terminal is used to connect the negative terminal of the battery pack to form a first negative circuit L2; the charging capacitor C1 includes a first electrode and a second electrode, the first electrode is electrically connected to the first positive charging terminal, and the second electrode is electrically connected to the first negative charging terminal, the first contactor KM1 is connected in series with the charging capacitor C1, and is located between the first positive circuit L1 and the first negative circuit L2. The battery pack charging circuit also includes contactor KM4, contactor KM5 and contactor KM6. When the electric vehicle is powered on, or the electric vehicle is charged using a charging gun, contactor KM4, contactor KM5 and contactor KM6 are in a closed state, and the charging circuit of the battery pack is turned on. The battery pack charging circuit also includes Y capacitor C2 and Y capacitor C3. Y capacitor C2 is connected between the positive terminal of the battery pack and the ground wire, and Y capacitor C3 is connected between the negative terminal of the battery pack and the ground wire.

[0037] When the Y capacitor C2 leaks, the voltage across the Y capacitor C3 is approximately equal to the battery pack voltage, and the energy stored in the Y capacitor C3 is relatively high. If the user accidentally touches the first positive charging terminal and the vehicle body ground GND, forming a human body resistance R1, the energy stored in the Y capacitor C2 will be discharged through the human body resistance R1, forming a Figure 2 The energy discharge circuit indicated by the middle arrow may cause electric shock to the human body. At this time, the vehicle control system controls the first contactor KM1 to automatically disconnect, thereby immediately cutting off the energy discharge circuit to prevent electric shock accidents. Since the first contactor KM1 is arranged between the first positive circuit L1 and the first negative circuit L2, it can effectively prevent the large current flowing through the first contactor KM1 when the charging port 1 is charging, thereby preventing the first contactor KM1 from sintering, and greatly reducing the current flowing through the first contactor KM1. Therefore, the battery pack charging circuit of the embodiment of the utility model can select the first contactor KM1 with a smaller rated current, thereby reducing the volume of the first contactor KM1, which helps to save the layout space of the battery pack charging circuit on the whole vehicle, and also helps to save the power distribution space occupied by the battery pack charging circuit on the whole vehicle. Optionally, refer to Figure 3 , the first contactor is connected between the first electrode and the first positive charging terminal, or, the first contactor is connected between the second electrode and the first negative charging terminal.

[0038] Specifically, if Figure 3 As shown, the first contactor KM1 can be connected between the first electrode of the charging capacitor C1 and the first positive charging terminal, one end of the first contactor KM1 is electrically connected to the first electrode of the charging capacitor C1, and the other end is electrically connected to the first positive charging terminal, so as to control the on-off of the branch where the charging capacitor C1 is located from the positive side; the first contactor KM1 can also be connected between the second electrode of the charging capacitor C1 and the first negative charging terminal, one end of the first contactor KM1 is electrically connected to the second electrode of the charging capacitor C1, and the other end is electrically connected to the first negative charging terminal, so as to control the on-off of the branch where the charging capacitor C1 is located from the negative side, and the above two connection methods both ensure that the first contactor KM1 is arranged between the first positive circuit L1 and the first negative circuit L2.

[0039] Optionally, refer to Figure 3 The battery pack charging circuit also includes a voltage-relief resistor; one end of the voltage-relief resistor is electrically connected to the first electrode, and the other end of the voltage-relief resistor is electrically connected to the second electrode.

[0040] Specifically, if Figure 3As shown, the battery pack charging circuit also includes a voltage relief resistor R2; one end of the voltage relief resistor R2 is electrically connected to the first electrode of the charging capacitor C1, and the other end is electrically connected to the second electrode of the charging capacitor C1, forming a parallel relationship with the charging capacitor C1. The voltage relief resistor R2 can discharge the voltage of the charging capacitor C1 to prevent the voltage of the charging capacitor C1 from being too high when the external load changes, thereby playing a certain protective role on the charging capacitor C1 and improving the working safety of the battery pack charging circuit.

[0041] Optionally, refer to Figure 3 , one end of the first contactor is electrically connected to the voltage relief resistor, and the other end of the first contactor is electrically connected to the first positive charging terminal; or, one end of the first contactor is electrically connected to the voltage relief resistor, and the other end of the first contactor is electrically connected to the first negative charging terminal.

[0042] Specifically, in some embodiments, Figure 3 As shown, the first contactor KM1 can be connected between the voltage-relief resistor R2 and the first positive charging terminal, one end of the first contactor KM1 is electrically connected to the voltage-relief resistor R2 and the first electrode of the charging capacitor C1, respectively, and the other end is electrically connected to the first positive charging terminal; or, the first contactor KM1 can also be connected between the voltage-relief resistor R2 and the first negative charging terminal, one end of the first contactor KM1 is electrically connected to the second electrode of the voltage-relief resistor R2 and the charging capacitor C1, respectively, and the other end is electrically connected to the first negative charging terminal. In the above two connection modes, the conduction or disconnection of the first contactor KM1 will not affect the voltage discharge effect of the voltage-relief resistor R2 on the charging capacitor C1, which helps to ensure the safe use of the charging capacitor C1.

[0043] Optionally, one end of the first contactor is electrically connected to the pressure relief resistor, and the other end of the first contactor is electrically connected to the first electrode; or, one end of the first contactor is electrically connected to the pressure relief resistor, and the other end of the first contactor is electrically connected to the second electrode.

[0044] Specifically, in some embodiments, the first contactor KM1 can be connected between the voltage relief resistor R2 and the charging capacitor C1, for example, one end of the first contactor KM1 is electrically connected to the voltage relief resistor R2 and the first positive charging terminal, respectively, and the other end is electrically connected to the first electrode of the charging capacitor C1, or, one end of the first contactor KM1 is electrically connected to the voltage relief resistor R2 and the first negative charging terminal, respectively, and the other end is electrically connected to the second electrode of the charging capacitor C1.

[0045] Optionally, refer to Figure 2 The battery pack charging circuit also includes a second contactor 6; the second contactor 6 is connected between the boost module 5 and the charging capacitor 3.

[0046] Specifically, if Figure 2 As shown, the battery pack charging circuit also includes a second contactor 6 ( Figure 3 and Figure 4 The second contactor 6 is connected between the boost module 5 and the charging capacitor 3, and can control the on and off of the circuit between the boost module 5 and the charging capacitor C1. In the case of a motor failure, the circuit between the boost module 5 and the charging capacitor C1 can be cut off in time to avoid damage to the charging circuit of the entire battery pack. At the same time, the second contactor 6 is arranged on the first positive circuit, and can also control the on or off of the charging circuit. When the charging port is charging the battery pack normally, the second contactor 6 is in a closed state. When the battery pack is fully charged, the second contactor 6 is in a disconnected state.

[0047] Optionally, refer to Figure 3 The battery pack charging circuit also includes a third contactor; the third contactor is connected to the first negative pole circuit and is used to control the on and off of the first negative pole circuit.

[0048] Specifically, the battery pack charging circuit also includes a third contactor KM3, which is connected to the first negative pole circuit and can also control the conduction or disconnection of the charging circuit. When the charging port is normally charging the battery pack, the third contactor KM3 is in a closed state. When the battery pack is completely charged, the third contactor KM3 is in a disconnected state.

[0049] Optionally, refer to Figure 4 The battery pack charging circuit also includes a second positive charging terminal and a second negative charging terminal; the second positive charging terminal is used to connect the positive terminal of the battery pack to form a second positive circuit, and the second negative charging terminal is used to connect the negative terminal of the battery pack to form a second negative circuit.

[0050] Specifically, the second positive charging terminal and the second negative charging terminal form a charging port 2, the second positive charging terminal is used to connect the positive terminal of the battery pack to form a second positive circuit, and the second negative charging terminal is used to connect the negative terminal of the battery pack to form a second negative circuit. In the case where the battery pack charging circuit includes two charging ports, dual-gun charging can be achieved, the main charging gun can be charged by boosting, and the auxiliary charging gun can be charged by direct connection. The main charging gun and the auxiliary charging gun merge the current in the high-voltage distribution box, and then charge the battery pack, thereby greatly improving the charging efficiency of the battery pack.

[0051] An embodiment of the utility model further provides a battery pack, comprising a battery unit and the battery pack charging circuit as described in any one of the above items, wherein the battery unit is electrically connected to the battery pack charging circuit.

[0052] Specifically, the battery pack also includes a shell having a accommodating cavity, the battery cell is arranged in the accommodating cavity, the battery cell is electrically connected to the battery pack charging circuit, and charging the battery pack is essentially charging the battery cell through the battery pack charging circuit.

[0053] An embodiment of the utility model further provides an electrical device, comprising the aforementioned battery pack and any one of the aforementioned battery pack charging circuits, wherein the battery pack is electrically connected to the battery pack charging circuit.

[0054] Specifically, the electrical device includes an energy storage device and an electric vehicle, etc. The energy storage device includes but is not limited to an energy storage cabinet, a control cabinet, an integrated cabinet, etc. The electric vehicle includes but is not limited to a pure electric vehicle and a hybrid vehicle. The electrical device includes a battery pack and a battery pack charging circuit of any of the aforementioned embodiments. The battery pack includes a shell and a battery cell. The shell has a accommodating cavity. The battery cell is arranged in the accommodating cavity. The electrical connection between the battery pack and the battery pack charging circuit is essentially the electrical connection between the battery pack charging circuit and the battery cells in the battery pack. The battery pack provides power output for the electrical equipment to ensure the normal operation of the electrical equipment.

[0055] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A battery pack charging circuit, characterized in that: It includes a first positive charging terminal, a first negative charging terminal, a charging capacitor and a first contactor; The first positive charging terminal is used to connect the positive terminal of the battery pack to form a first positive circuit, and the first negative charging terminal is used to connect the negative terminal of the battery pack to form a first negative circuit; One end of the charging capacitor is electrically connected to the first positive circuit, and the other end of the charging capacitor is electrically connected to the first negative circuit; The first contactor is connected in series with the charging capacitor and is located between the first positive circuit and the first negative circuit.

2. The battery pack charging circuit according to claim 1, characterized in that: The first contactor is connected between the charging capacitor and the first positive circuit, or the first contactor is connected between the charging capacitor and the first negative circuit.

3. The battery pack charging circuit according to claim 1, characterized in that: The charging capacitor includes a first electrode and a second electrode, the first electrode is electrically connected to the first positive charging terminal, and the second electrode is electrically connected to the first negative charging terminal.

4. The battery pack charging circuit according to claim 3, characterized in that: It also includes a pressure relief resistor; One end of the voltage-relief resistor is electrically connected to the first electrode, and the other end of the voltage-relief resistor is electrically connected to the second electrode.

5. The battery pack charging circuit according to claim 4, characterized in that: One end of the first contactor is electrically connected to the voltage relief resistor, and the other end of the first contactor is electrically connected to the first positive charging terminal; Alternatively, one end of the first contactor is electrically connected to the voltage relief resistor, and the other end of the first contactor is electrically connected to the first negative charging terminal.

6. The battery pack charging circuit according to claim 4, characterized in that: One end of the first contactor is electrically connected to the voltage relief resistor, and the other end of the first contactor is electrically connected to the first electrode; Alternatively, one end of the first contactor is electrically connected to the voltage relief resistor, and the other end of the first contactor is electrically connected to the second electrode.

7. The battery pack charging circuit according to claim 1, characterized in that: Also includes a boost module; The boost module is connected between the charging capacitor and the battery pack, and is used to boost the voltage of the battery pack charging circuit.

8. The battery pack charging circuit according to claim 7, characterized in that: Also included is a second contactor; The second contactor is connected between the boost module and the charging capacitor.

9. The battery pack charging circuit according to claim 1, characterized in that: Also included is a third contactor; The third contactor is connected to the first negative circuit and is used to control the on and off of the first negative circuit.

10. The battery pack charging circuit according to claim 1, characterized in that: Also included is a second positive charging terminal and a second negative charging terminal; The second positive charging terminal is used to connect to the positive terminal of the battery pack to form a second positive circuit, and the second negative charging terminal is used to connect to the negative terminal of the battery pack to form a second negative circuit.

11. An electrical device, characterized in that: It comprises a battery pack and a battery pack charging circuit as claimed in any one of claims 1 to 10, wherein the battery pack is electrically connected to the battery pack charging circuit.

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