Charging / discharging system and charging device

Abstract

The utility model relates to a charging and discharging system and a charging device. According to the utility model, the system comprises a charging circuit, a first end of the charging circuit is connected with a bus of the system, and a second end of the charging circuit is connected with a battery connection end of the system; the first end of the discharging circuit is connected with a bus of the system, and the second end of the discharging circuit is connected with the load connecting end of the system; wherein the charging circuit and the discharging circuit multiplex a part of rectification devices. The problem that an alternating-current charging circuit and a motor driving circuit in the system are difficult to integrate can be solved, and cost and size are effectively reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of equipment charging, and more specifically, to a charging and discharging system and a charging device. Background Art

[0002] With the rapid development of charging technology and battery technology, the charging power required by load devices is increasing. At present, in order to increase the charging power, the power grid can supply power to the load devices through the power grid discharge circuit, and supplement the power grid through the energy storage battery, but the power grid discharge circuit and the battery charging circuit are independent circuits and difficult to integrate. Utility Model Content

[0003] The embodiments of the present disclosure provide a charging and discharging system and a charging device, which can reduce cost and volume.

[0004] According to a first aspect of the present utility model, a charging control system is provided, the system comprising:

[0005] A charging circuit, wherein a first end of the charging circuit is connected to a busbar of the system, and a second end of the charging circuit is connected to a battery connection terminal of the system;

[0006] a discharge circuit, wherein a first end of the discharge circuit is connected to a busbar of the system, and a second end of the discharge circuit is connected to a load connection end of the system;

[0007] Wherein, the charging circuit and the discharging circuit reuse some rectifying devices.

[0008] Optionally, the charging circuit includes a first DC conversion circuit and an AC / DC conversion circuit; a first end of the AC / DC conversion circuit is connected to a busbar of the system, a second end of the AC / DC conversion circuit is connected to a first end of the first DC conversion circuit, and a second end of the first DC conversion circuit is connected to an energy storage battery;

[0009] The charging circuit and the discharging circuit reuse some rectifying devices, including: the charging circuit and the discharging circuit reuse the AC-DC conversion circuit.

[0010] Optionally, the charging circuit further includes a first switch, a first end of the first switch is connected to a second end of the AC-DC conversion circuit, and a second end of the first switch is connected to the first DC conversion circuit;

[0011] Wherein, when the first switch is closed, the charging circuit converts the first alternating current output by the bus into a first direct current and outputs it to the energy storage battery; when the first switch is opened, the discharging circuit converts the first alternating current output by the bus into a second direct current and outputs it to the load device.

[0012] Optionally, there are multiple first DC conversion circuits, and the first ends of different first DC conversion circuits are connected to the second ends of the AC-DC conversion circuit, and the second ends of different first DC conversion circuits are connected to different energy storage batteries;

[0013] There are multiple first switches, and the first ends of different first switches are connected to the second end of the AC-DC conversion circuit, and different first switches are connected to the first end of the corresponding first DC conversion circuit.

[0014] Optionally, the discharge circuit further includes a second DC conversion circuit, a first end of the second DC conversion circuit is connected to a second end of the AC-DC conversion circuit, and a second end of the second DC conversion circuit is connected to a load connection end of the system.

[0015] Optionally, the system further comprises a second switch, wherein a first end of the second switch is connected to a first end of the first DC conversion circuit, and a second end of the second switch is connected to a second end of the second DC conversion circuit;

[0016] Wherein, when the second switch is closed, the first DC conversion circuit outputs the third DC power output from the battery connection end of the system to the load connection end of the system.

[0017] Optionally, there are multiple second DC conversion circuits, and the first ends of different second DC conversion circuits are connected to the second end of the AC-DC conversion circuit, and the second ends of different second DC conversion circuits are connected to load connection ends of different systems;

[0018] There are multiple second switches, and the first ends of different second switches are connected to the first end of the first DC conversion circuit, and different second switches are connected to the second ends of the corresponding second DC conversion circuits.

[0019] Optionally, there are multiple first DC conversion circuits, and the first ends of different first DC conversion circuits are connected to the second end of the AC-DC conversion circuit, and the second ends of different first DC conversion circuits are connected to battery connection ends of different systems;

[0020] The system further includes a third switch connected between second ends of adjacent second DC conversion circuits;

[0021] When the first battery connection terminal of the system discharges to the first load connection terminal of the system, the second switch corresponding to the first battery connection terminal of the system is closed, and the third switch between the second DC conversion circuit corresponding to the first battery connection terminal of the system and the second DC conversion circuit corresponding to the first load connection terminal of the system is closed; wherein the battery connection terminal of the system includes a first battery connection terminal, and the load connection terminal of the system includes a first load connection terminal.

[0022] According to a second aspect of the utility model, there is provided a charging device, comprising an auxiliary power supply battery and a charging and discharging system as described in the first aspect;

[0023] The auxiliary power supply battery is connected to the battery connection terminal of the charging and discharging system, and the load connection terminal of the charging and discharging system is connected to a load device.

[0024] Optionally, a power supply system is further included, the output end of the power supply system is connected to the bus bar of the charging and discharging system, and the power supply system supplies power to the auxiliary power supply battery or the load device.

[0025] Optionally, the power supply system includes a transformer, an AC-DC converter and a photovoltaic module;

[0026] The first end of the transformer is connected to the power grid, the second end of the transformer serves as the output end of the power supply system, the first end of the AC-DC converter is connected to the photovoltaic component, and the second end of the AC-DC converter serves as the output end of the power supply system.

[0027] One technical effect of the utility model is that the charging circuit can convert the first alternating current outputted by the bus of the system into the first direct current to charge the energy storage battery, and the discharging circuit can convert the first alternating current outputted by the bus of the system into the second direct current to power the load device, and the charging circuit and the discharging circuit reuse some rectifier devices, so that the charging circuit and the discharging circuit are integrated into a whole, which improves the integration of the charging and discharging system, reduces the volume of the charging and discharging system on the one hand, and reduces the manufacturing cost of the charging and discharging system on the other hand. The charging and discharging system of the utility model can be applied in vehicles.

[0028] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present utility model and, together with the description, are used to explain the principles of the present utility model.

[0030] Figure 1is a structural block diagram of a charging and discharging system according to an embodiment;

[0031] Figure 2 is a circuit diagram of a charging and discharging system according to another embodiment;

[0032] Figure 3 is a circuit diagram of a charging and discharging system according to another embodiment;

[0033] Figure 4 is a circuit diagram of a charging and discharging system according to another embodiment.

[0034] Description of the drawings:

[0035] Charging circuit 10; first DC conversion circuit 11; AC-DC conversion circuit 12; discharge circuit 20; second DC conversion circuit 21; bus 30; energy storage battery 40; load device 50; power grid 60; transformer 61; photovoltaic module 70; AC-DC converter 71; switch unit 80. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0037] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.

[0038] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0039] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0040] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0041] See also Figure 1 As shown, the charging and discharging system of the embodiment of the present disclosure is described.

[0042] The charging and discharging system of the embodiment of the present disclosure includes a charging circuit 10 and a discharging circuit 20 .

[0043] A first end of the charging circuit 10 is connected to a bus bar 30 of the charging and discharging system, and a second end of the charging circuit 10 is connected to a battery connection end of the charging and discharging system.

[0044] The first end of the discharge circuit 20 is connected to the busbar 30 of the charge-discharge system, and the second end of the discharge circuit 20 is connected to the load connection end of the charge-discharge system;

[0045] The charging circuit 10 and the discharging circuit 20 reuse some rectifying devices.

[0046] In this embodiment, the busbar of the charging and discharging system may be an AC busbar or a DC busbar. The following is a specific description using the busbar 30 of the charging and discharging system as an AC busbar.

[0047] In this embodiment, the battery connection end of the charging and discharging system may be an end where the energy storage battery 40 and the second end of the charging circuit 10 are connected.

[0048] In this embodiment, the load connection end of the charge and discharge system may be an end connected to the load device 50 and the second end of the discharge circuit 20. The load device 50 may be, for example, an electric vehicle, a smart locker, an aircraft, or an electric bicycle, etc., which is not limited here.

[0049] In this embodiment, the charging circuit 10 can be an AC-DC conversion circuit, which can convert the first AC power output by the bus 30 of the charging and discharging system into a first DC power to charge the energy storage battery 40 through the second end of the charging circuit 10.

[0050] In this embodiment, the discharge circuit 20 may be an AC-DC conversion circuit, which may convert the first AC power outputted by the bus 30 of the charging and discharging system into a second DC power to supply power to the load device 50 through the second end of the discharge circuit 20 .

[0051] In other words, the charging circuit 10 can convert the first alternating current output by the bus 30 of the charging and discharging system into a first direct current to charge the energy storage battery 40, and the discharging circuit 20 can convert the first alternating current output by the bus 30 of the charging and discharging system into a second direct current to power the load device 50, and the charging circuit 10 and the discharging circuit 20 reuse some rectifier devices, so that the charging circuit 10 and the discharging circuit 20 are integrated into a whole, which improves the integration of the charging and discharging system and, on the one hand, reduces the volume of the charging and discharging system.

[0052] In some embodiments, the charging circuit 10 includes a first DC conversion circuit 11 and an AC / DC conversion circuit 12; a first end of the AC / DC conversion circuit 12 is connected to a bus 30 of a charging and discharging system, a second end of the AC / DC conversion circuit 12 is connected to a first end of the first DC conversion circuit 11, and a second end of the first DC conversion circuit 11 is connected to an energy storage battery 40; wherein the charging circuit 10 and the discharging circuit 20 reuse some rectifying devices, including: the charging circuit 10 and the discharging circuit 20 reuse the AC / DC conversion circuit 12.

[0053] In this embodiment, the first DC conversion circuit 11 may be a DC-DC conversion circuit, and the DC-DC conversion circuit may be a DC boost circuit or a DC buck circuit, which is not limited herein.

[0054] In some examples, the AC-DC conversion circuit 12 may be an AC-DC conversion circuit, which may convert the first AC power outputted by the bus 30 of the charging and discharging system into a fourth DC power and output it to the first DC conversion circuit 11, and the first DC conversion circuit 11 may then convert the fourth DC power into a first DC power and output it to the energy storage battery 40. The first DC conversion circuit 11 may convert the fifth DC power outputted by the energy storage battery 40 into a sixth DC power, and the AC-DC conversion circuit may also convert the sixth DC power outputted by the first DC conversion circuit 11 into a second AC power and output it to the bus 30 of the charging and discharging system, so as to feed back electric energy to the grid 60 or the photovoltaic module 70.

[0055] In other words, by setting the multiplexed part of the rectifying device as the AC-DC conversion circuit 12, the charging circuit 10 and the discharging circuit 20 can be integrated into a whole while improving the working efficiency of the AC-DC conversion circuit 12, thereby reducing the manufacturing cost of the charging and discharging system.

[0056] In some embodiments, the discharge circuit 20 further includes a second DC conversion circuit 21, a first end of the second DC conversion circuit 21 is connected to a second end of the AC / DC conversion circuit 12, and a second end of the second DC conversion circuit 21 is connected to a load connection end of the system.

[0057] In some examples, the second DC conversion circuit 21 and the AC / DC conversion circuit 12 may constitute a charging station for the vehicle.

[0058] In this embodiment, the second DC conversion circuit 21 may be a DC-DC conversion circuit, and the DC-DC conversion circuit may be a DC boost circuit or a DC buck circuit, which is not limited herein.

[0059] In some examples, the AC-DC conversion circuit can convert the first AC power outputted by the bus 30 of the charging and discharging system into the seventh DC power and output it to the second DC conversion circuit, and the second DC conversion circuit 21 can convert the seventh DC power into the second DC power and output it to the load device 50. The second DC conversion circuit 21 can also convert the eighth DC power outputted by the load device 50 into the ninth DC power, and the AC-DC conversion circuit can also convert the ninth DC power outputted by the second DC conversion circuit 21 into the third AC power and output it to the bus 30 of the charging and discharging system, so as to feed back electric energy to the grid 60, the photovoltaic module 70 or the energy storage battery 40.

[0060] In other words, the second DC conversion circuit 21 cooperates with the AC / DC conversion circuit 12 to supply power to the load device 50 .

[0061] In some embodiments, Figure 2 As shown, the charging circuit 10 also includes a first switch K1, a first end of the first switch K1 is connected to the second end of the AC-DC conversion circuit 12, and a second end of the first switch K1 is connected to the first DC conversion circuit 11; wherein, when the first switch K1 is closed, the charging circuit 10 converts the first AC power output by the bus 30 into a first DC power and outputs it to the energy storage battery 40; when the first switch K1 is disconnected, the discharge circuit 20 converts the first AC power output by the bus 30 into a second DC power and outputs it to the load device 50.

[0062] In other words, by setting the first switch K1, the bus 30 of the charging and discharging system can charge the energy storage battery 40 alone, charge the load device 50 alone, or charge the energy storage battery 40 and the load device 50 at the same time, thereby expanding the function of the charging and discharging system and further improving the utilization efficiency of the charging and discharging system.

[0063] In some embodiments, there are multiple first DC conversion circuits 11, and the first ends of different first DC conversion circuits 11 are connected to the second ends of the AC / DC conversion circuit 12, and the second ends of different first DC conversion circuits 11 are connected to different energy storage batteries 40; there are multiple first switches, and the first ends of different first switches are connected to the second ends of the AC / DC conversion circuit 12, and different first switches are connected to the first ends of corresponding first DC conversion circuits 11.

[0064] In some examples, such as Figure 4As shown, only the charging pile A1 is working, and the first switch can be the first switch Kj1 to the first switch Kjn. When the first switch Kj1 is closed, the energy storage battery 40B1 supplies power to the load device 50L1 connected to the charging pile A1 through the charging circuit 10. When the first switch Kj1 and the first switch Kj3 are closed, the energy storage batteries 40B1 and 40B2 supply power to the load device 50L1 connected to the charging pile A1 through the charging circuit 10.

[0065] In other words, the charging and discharging system is configured with multiple battery connection terminals to connect different energy storage batteries 40, and, with the cooperation of multiple first switches, multiple energy storage batteries 40 can simultaneously power a load device 50, or multiple energy storage batteries 40 can power a load device 50 one by one, further expanding the function of the charging and discharging system to improve the power supply efficiency of the charging and discharging system for the load device 50 and provide the load device 50 with long-lasting and stable direct current.

[0066] In some embodiments, Figure 2 As shown, the charging and discharging system also includes a second switch K2, a first end of the second switch K2 is connected to a first end of the first DC conversion circuit 11, and a second end of the second switch K2 is connected to a second end of the second DC conversion circuit 21; wherein, when the second switch K2 is closed, the first DC conversion circuit 11 outputs the third DC power output from the battery connection end of the charging and discharging system to the load connection end of the charging and discharging system.

[0067] In other words, by setting the second switch K2, the energy storage battery 40 can directly supply power to the load device 50 through the first DC conversion circuit 11, thereby effectively improving the conversion efficiency of supplying power to the load device 50 and effectively reducing the energy loss of the charging and discharging system.

[0068] In some embodiments, there are multiple second DC conversion circuits 21, and the first ends of different second DC conversion circuits 21 are connected to the second end of the AC / DC conversion circuit 12, and the second ends of different second DC conversion circuits 21 are connected to the load connection ends of different charging and discharging systems; there are multiple second switches, and the first ends of different second switches are connected to the first end of the first DC conversion circuit 11, and different second switches are connected to the second ends of the corresponding second DC conversion circuits 21.

[0069] In some examples, such as Figure 3 As shown, the plurality of second switches are respectively a second switch K21 to a second switch K2n. When the second switch K22 is closed, the energy storage battery 40 can charge the load device L2 through the first DC conversion circuit 11.

[0070] In other words, by setting a plurality of second switches, one energy storage battery 40 can be effectively controlled to supply power to different load devices 50, thereby further expanding the functions of the charging and discharging system and effectively improving the application scenarios of the charging and discharging system.

[0071] In some examples, the charging and discharging system may further include a switch unit 80, which is disposed between the load device 50 and the second DC conversion circuit 21 to regulate the first alternating current output by the plurality of discharge circuits 20 to be input to one or more load devices 50. For example, a load device 50 requires 500KW of first alternating current, and the five discharge circuits 20 may respectively output 100KW of first alternating current. The switch unit 80 may regulate the first alternating current output by the five discharge circuits 20 into 500KW of first alternating current and output it to the load device 50.

[0072] In some embodiments, there are multiple first DC conversion circuits, and the first ends of different first DC conversion circuits are connected to the second ends of the AC / DC conversion circuit 12, and the second ends of different first DC conversion circuits are connected to the battery connection ends of different charging and discharging systems; the charging and discharging system also includes a third switch, and the third switch is connected between the second ends of adjacent second DC conversion circuits; wherein, when the first battery connection end of the charging and discharging system discharges to the first load connection end of the charging and discharging system, the second switch corresponding to the first battery connection end of the charging and discharging system is closed, and the third switch between the second DC conversion circuit corresponding to the first battery connection end of the charging and discharging system and the second DC conversion circuit corresponding to the first load connection end of the system is closed; wherein, the battery connection end of the charging and discharging system includes the first battery connection end, and the load connection end of the charging and discharging system includes the first load connection end.

[0073] like Figure 4 As shown, the plurality of first switches are, for example, first switches Kj1 to first switches Kjn, the plurality of second switches are, for example, second switches Km1 to second switches Kmn, and the plurality of third switches are, for example, Kh1 to third switches Khn-1. When the energy storage battery 40B1 supplies power to the load device 50L2, the second switch km1 is closed and the third switch kh1 is closed, so as to instruct an energy storage battery 40 to supply power to the load device 50 according to demand.

[0074] In other words, by setting a plurality of first switches, second switches and third switches to cooperate with each other,

[0075] In some examples, the charging and discharging system further includes a control circuit, which can be communicatively connected to the first DC conversion circuit, the AC-DC conversion circuit, or the second conversion circuit, so that the first DC conversion circuit, the AC-DC conversion circuit, or the second conversion circuit adjusts the conversion efficiency under the control of the control circuit. The control circuit can also be electrically connected to the first switch, the second switch, and the third switch, so that the first switch, the second switch, and the third switch are opened or closed under the control of the control circuit.

[0076] In some examples, the number of energy storage batteries 40 may be less than or equal to the number of second DC conversion circuits 21, that is, the second ends of some second DC conversion circuits 21 are not connected to any second switches, that is, any energy storage battery 40 cannot discharge to the load connection end of some charging and discharging systems.

[0077] According to the charging device provided by the embodiment of the present disclosure, the charging device includes an auxiliary power supply battery and a charging and discharging system of any of the above embodiments. The auxiliary power supply battery is connected to the battery connection terminal of the charging and discharging system, and the load connection terminal of the charging and discharging system is connected to the load device.

[0078] In other words, the charging device is, for example, a charging pile or a power supply cabinet, etc., which is not limited here. The charging device is equipped with the charging and discharging system, which can effectively improve the utilization efficiency of the internal space of the charging device and reduce the manufacturing cost of the charging device.

[0079] In some embodiments, the charging device further includes a power supply system, an output end of the power supply system is connected to a bus bar of the charging and discharging system, and the power supply system supplies power to an auxiliary power supply battery or a load device.

[0080] In this embodiment, the power supply system is, for example, a power grid or clean energy, and the clean energy is, for example, a wind power generation device or a solar power generation device, etc., which is not limited here. In other words, by setting up a power supply system, the charging device can supply power to different load devices.

[0081] In some embodiments, Figure 4 As shown, the power supply system may include a transformer 61, an AC-DC converter 71 and a photovoltaic module 70; wherein the first end of the transformer 61 is connected to the power grid, the second end of the transformer 61 serves as the output end of the power supply system, the first end of the AC-DC converter 71 is connected to the photovoltaic module 70, and the second end of the AC-DC converter 71 serves as the output end of the power supply system.

[0082] In this embodiment, the transformer 61 is, for example, a DC-AC conversion circuit, which can convert the tenth DC power outputted by the power grid into the first AC power and output it to the bus of the charging and discharging system. The AC-DC converter 71 is, for example, an AC-DC conversion circuit, which can convert the eleventh DC power outputted by the photovoltaic module 70 into the first AC power and output it to the bus of the charging and discharging system. In other words, the charging device can charge the load device through different power supplies, which expands the application scenarios of the charging device.

[0083] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A charging and discharging system, characterized in that: The system comprises: A charging circuit, wherein a first end of the charging circuit is connected to a busbar of the system, and a second end of the charging circuit is connected to a battery connection terminal of the system; a discharge circuit, wherein a first end of the discharge circuit is connected to a busbar of the system, and a second end of the discharge circuit is connected to a load connection end of the system; Wherein, the charging circuit and the discharging circuit reuse some rectifying devices; The charging circuit includes a first DC conversion circuit and an AC / DC conversion circuit; a first end of the AC / DC conversion circuit is connected to the busbar of the system, a second end of the AC / DC conversion circuit is connected to a first end of the first DC conversion circuit, and a second end of the first DC conversion circuit is connected to an energy storage battery; Wherein, the charging circuit and the discharging circuit reuse some rectifying devices, including: the charging circuit and the discharging circuit reuse the AC-DC conversion circuit; The discharge circuit further includes a second DC conversion circuit, a first end of the second DC conversion circuit is connected to a second end of the AC / DC conversion circuit, and a second end of the second DC conversion circuit is connected to a load connection end of the system.

2. The system according to claim 1, characterized in that The charging circuit further includes a first switch, a first end of the first switch is connected to a second end of the AC-DC conversion circuit, and a second end of the first switch is connected to the first DC conversion circuit; Wherein, when the first switch is closed, the charging circuit converts the first alternating current output by the bus into a first direct current and outputs it to the energy storage battery; when the first switch is opened, the discharging circuit converts the first alternating current output by the bus into a second direct current and outputs it to the load device.

3. The system according to claim 2, characterized in that There are multiple first DC conversion circuits, and the first ends of different first DC conversion circuits are connected to the second ends of the AC-DC conversion circuit, and the second ends of different first DC conversion circuits are connected to different energy storage batteries; There are multiple first switches, and the first ends of different first switches are connected to the second end of the AC-DC conversion circuit, and different first switches are connected to the first end of the corresponding first DC conversion circuit.

4. The system according to claim 1, characterized in that The system further includes a second switch, a first end of the second switch being connected to a first end of the first DC conversion circuit, and a second end of the second switch being connected to a second end of the second DC conversion circuit; Wherein, when the second switch is closed, the first DC conversion circuit outputs the third DC power output from the battery connection end of the system to the load connection end of the system.

5. The system according to claim 4, characterized in that There are multiple second DC conversion circuits, and the first ends of different second DC conversion circuits are connected to the second end of the AC-DC conversion circuit, and the second ends of different second DC conversion circuits are connected to load connection ends of different systems; There are multiple second switches, and the first ends of different second switches are connected to the first end of the first DC conversion circuit, and different second switches are connected to the second ends of the corresponding second DC conversion circuits.

6. The system according to claim 5, characterized in that There are multiple first DC conversion circuits, and the first ends of different first DC conversion circuits are connected to the second ends of the AC-DC conversion circuit, and the second ends of different first DC conversion circuits are connected to battery connection ends of different systems; The system further includes a third switch connected between second ends of adjacent second DC conversion circuits; When the first battery connection terminal of the system discharges to the first load connection terminal of the system, the second switch corresponding to the first battery connection terminal of the system is closed, and the third switch between the second DC conversion circuit corresponding to the first battery connection terminal of the system and the second DC conversion circuit corresponding to the first load connection terminal of the system is closed; wherein the battery connection terminal of the system includes a first battery connection terminal, and the load connection terminal of the system includes a first load connection terminal.

7. A charging device, characterized in that: Comprising an auxiliary power supply battery and a charging and discharging system as claimed in any one of claims 1 to 6; The auxiliary power supply battery is connected to the battery connection terminal of the charging and discharging system, and the load connection terminal of the charging and discharging system is connected to a load device.

8. The device according to claim 7, characterized in that It also includes a power supply system, the output end of which is connected to the busbar of the charging and discharging system, and the power supply system supplies power to the auxiliary power supply battery or the load device.

9. The device according to claim 8, characterized in that The power supply system includes a transformer, an AC-DC converter and a photovoltaic module; The first end of the transformer is connected to the power grid, the second end of the transformer serves as the output end of the power supply system, the first end of the AC-DC converter is connected to the photovoltaic component, and the second end of the AC-DC converter serves as the output end of the power supply system.

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