An energy storage system

Abstract

The utility model discloses a kind of energy storage systems, belong to energy storage device technical field, to solve the power supply of energy storage system in prior art mainly comes from single power supply source such as energy storage battery, the structure of switching power supply source is more complex, while it is difficult to guarantee higher available capacity of energy storage battery.The first power taking circuit, the second power taking circuit, the third power taking circuit and electric energy conversion device are included;The output end of the electric energy conversion device is externally connected to the power supply target, and the input end of the electric energy conversion device is respectively connected to the output end of the first power taking circuit, the second power taking circuit and the third power taking circuit;The utility model can supply power for electric energy conversion device by off-grid renewable energy power generation system, energy storage unit and power grid, and preferentially use off-grid renewable energy power generation system and power grid to supply power for electric energy conversion device, simplify the switching structure of power supply source, and further improve the available capacity of energy storage unit.

Description

Technical Field

[0001] This utility model relates to an energy storage system and belongs to the technical field of energy storage devices. Background Technology

[0002] With the vigorous promotion of renewable energy, rising energy prices, high residential electricity prices, and widening peak-valley electricity price differences, residential energy storage systems are experiencing explosive growth globally. Residential energy storage systems mainly consist of energy storage converters, energy storage battery systems, and energy management systems (EMS). The battery system includes battery modules and the BMS. Battery modules are used for energy storage, the BMS is mainly used for battery monitoring and protection, and the EMS is used for energy management and monitoring of the energy storage system. Therefore, the stability of the power supply to the BMS and EMS is crucial. Currently, the power supply to the BMS and EMS of existing residential energy storage products mainly comes from the energy storage batteries. The reliability and stability of a single power source are not high, and it can affect the available capacity of the batteries. Multiple power sources, such as CN117477740A, provide an energy storage system and its control method. This patented power supply module includes a first power conversion module, a second power conversion module, a third power conversion module, an uninterruptible power supply, and a switching module, etc. The structure requiring switching power sources is complex and makes it difficult to guarantee higher available capacity of the energy storage batteries.

[0003] In summary, the power supply of existing energy storage systems mainly comes from a single power source such as energy storage batteries, which can easily lead to data loss in the energy storage system. When multiple power sources are used, the structure for switching power sources is relatively complex, and it is difficult to ensure a higher usable capacity of energy storage batteries, thus affecting the actual use effect of the energy storage system. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an energy storage system that uses only one power conversion device. This device can be powered by off-grid renewable energy generation systems, energy storage units, and the power grid, giving it multiple power sources. This ensures stable power supply to the battery management system, energy management system, and cloud platform, preventing data loss in the energy storage system. Furthermore, this invention prioritizes using off-grid renewable energy generation systems and the power grid to power the power conversion device, simplifying the power source switching structure and further increasing the available capacity of the energy storage unit.

[0005] To solve the above-mentioned technical problems, this utility model is implemented using the following technical solution: This utility model provides an energy storage system, including a first power extraction circuit, a second power extraction circuit, a third power extraction circuit, and an energy conversion device; The output terminal of the power conversion device receives the power supply target externally, and the input terminal of the power conversion device is respectively connected to the output terminals of the first power extraction circuit, the second power extraction circuit, and the third power extraction circuit. The input terminals of the first power extraction circuit, the second power extraction circuit, and the third power extraction circuit are respectively connected to the energy storage unit, the off-grid renewable energy power generation system, and the power grid. The voltage output by the second power extraction circuit is higher than the voltage output by the third power extraction circuit, and the voltage output by the third power extraction circuit is higher than the voltage output by the first power extraction circuit. The first power supply circuit includes a DC circuit breaker; The second power supply circuit includes a first DC / DC module.

[0006] The above technical solution uses an energy storage unit, an off-grid renewable energy power generation system, and the power grid to input current to the power conversion device. The power conversion device can ensure a continuous and stable power supply to the target, avoiding data loss. By controlling the voltage output of the second power extraction circuit to be higher than that of the third power extraction circuit, and controlling the voltage output of the third power extraction circuit to be higher than that of the first power extraction circuit, the off-grid renewable energy power generation system and the power grid can be used to supply power to the power conversion device first, without the need to actively switch the power source, further improving the available capacity of the energy storage unit. Among them, the DC circuit breaker is used to control the on / off of the first power extraction circuit, and the first DC / DC module is used to control the output voltage of the second power extraction circuit.

[0007] Optionally, the input terminal of the DC circuit breaker is connected to the energy storage unit, and the output terminal of the DC circuit breaker is connected to the input terminal of the power conversion device.

[0008] The above technical solution allows for adjustment of the connection between the energy storage unit and the power conversion device via a DC circuit breaker, ensuring the safety of the system during use.

[0009] Optionally, the positive terminal of the energy storage unit is connected to the input terminal of the DC circuit breaker via a first fuse, and the negative terminal of the energy storage unit is connected to the input terminal of the DC circuit breaker via a second fuse.

[0010] The above technical solution can protect the system by using the first fuse and the second fuse when the energy storage unit fails, thus ensuring the safety of the system.

[0011] Optionally, the input terminal of the first DC / DC module is connected to the off-grid renewable energy power generation system, and the output terminal of the first DC / DC module is connected to the input terminal of the power conversion device.

[0012] The above technical solution can adjust the input voltage of the off-grid renewable energy power generation system through the first DC / DC module, thereby giving priority to using the off-grid renewable energy power generation system as the power source.

[0013] Optionally, a charging circuit is also included, the charging circuit including a second DC / DC module, the input terminal of the second DC / DC module being connected to the output terminal of the first DC / DC module, and the output terminal of the second DC / DC module being connected to both the output terminal of the DC circuit breaker and the input terminal of the power conversion device.

[0014] The above technical solution utilizes an off-grid renewable energy power generation system, where the output current passes sequentially through a first DC / DC module, a second DC / DC module, and a DC circuit breaker to charge the energy storage unit. This effectively utilizes energy and further ensures the usable capacity of the energy storage unit.

[0015] Optionally, the positive output terminal of the second DC / DC module is connected to both the output terminal of the DC circuit breaker and the input terminal of the power conversion device via a first DC relay, and the negative output terminal of the second DC / DC module is connected to both the output terminal of the DC circuit breaker and the input terminal of the power conversion device via a second DC relay.

[0016] In the above technical solution, the first DC relay and the second DC relay can disconnect the main circuit between the second DC / DC module and the DC circuit breaker according to actual usage requirements.

[0017] Optionally, the charging circuit further includes a DC / AC module, wherein the input terminal of the second DC / DC module is connected to the output terminal of the DC / AC module via a DC bus, the output terminal of the first DC / DC module is connected to the DC bus, the DC bus is connected to the input terminal of the power conversion device, and the input terminal of the DC / AC module is connected to the power grid via a circuit breaker.

[0018] In the above technical solution, the current output from the power grid can sequentially pass through the DC / AC module, the DC bus, the second DC / DC module, and the DC circuit breaker to charge the energy storage unit, further ensuring the usable capacity of the energy storage unit; the circuit breaker is used to control the connection or disconnection of the DC / AC module from the power grid, ensuring the safety of the system.

[0019] Optionally, the third power supply circuit includes a rectifier bridge, the input terminal of which is connected to the power grid, and the output terminal of which is connected to the input terminal of the power conversion device.

[0020] The above technical solution can adjust the input voltage of the power grid through a rectifier bridge, thereby giving the power grid as the second priority for power supply.

[0021] Optionally, the third power supply circuit is provided with a first diode, the second power supply circuit is provided with a second diode, and the first power supply circuit is provided with a third diode.

[0022] In the above technical solution, the first diode is used to protect the third power supply circuit; the second diode is used to protect the second power supply circuit; and the third diode is used to protect the first power supply circuit.

[0023] Optionally, the output voltage of the power conversion device is a preset value.

[0024] The above technical solution ensures the stability of the power conversion device when supplying power to the target by limiting the output voltage of the power conversion device.

[0025] Compared with the prior art, the beneficial effects achieved by this utility model are as follows: This energy storage system uses energy storage units, off-grid renewable energy power generation systems, and the power grid to input current to the power conversion device. The power conversion device can ensure a continuous and stable power supply to the target, avoiding data loss. By controlling the voltage output of the second power extraction circuit to be higher than that of the third power extraction circuit, and controlling the voltage output of the third power extraction circuit to be higher than that of the first power extraction circuit, the system prioritizes the use of off-grid renewable energy power generation systems and the power grid to power the power conversion device. This eliminates the need for active switching of power sources, simplifies the power source switching structure, and further improves the available capacity of the energy storage unit. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the system structure of an energy storage system according to an embodiment of the present utility model.

[0027] In the diagram: 1. Battery system; 2. Energy storage converter; 3. Off-grid renewable energy power generation system; 4. First DC / DC module; 5. Second DC / DC module; 6. Rectifier bridge; 7. Energy storage unit; 8. DC circuit breaker; 9. Power conversion device; 10. DC / AC module; 11. DC bus; 12. Circuit breaker; 13. First fuse; 14. Second fuse; 15. First DC relay; 16. Second DC relay. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0029] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] like Figure 1 As shown, this utility model provides an energy storage system, including a first power extraction circuit, a second power extraction circuit, a third power extraction circuit, and an energy conversion device 9; The output terminal of the power conversion device 9 receives the power supply target externally. The input terminal of the power conversion device 9 is connected to the output terminals of the first power extraction circuit, the second power extraction circuit, and the third power extraction circuit, respectively. The input terminals of the first power extraction circuit, the second power extraction circuit, and the third power extraction circuit are connected to the energy storage unit 7, the off-grid renewable energy power generation system 3, and the power grid, respectively. The voltage output by the second power extraction circuit is higher than that output by the third power extraction circuit, and the voltage output by the third power extraction circuit is higher than that output by the first power extraction circuit. The first power extraction circuit includes a DC circuit breaker 8. The second power extraction circuit includes a first DC / DC module 4.

[0032] Specifically, this application uses the energy storage unit 7, the off-grid renewable energy power generation system 3, and the power grid to input current to the power conversion device 9. The power conversion device 9 can ensure a continuous and stable power supply to the target to be powered, avoiding data loss. By controlling the voltage output of the second power extraction circuit to be higher than the voltage output of the third power extraction circuit, and controlling the voltage output of the third power extraction circuit to be higher than the voltage output of the first power extraction circuit, the off-grid renewable energy power generation system 3 and the power grid are given priority to power the power conversion device 9. There is no need to actively switch the power source, simplifying the power source switching structure and further improving the available capacity of the energy storage unit 7. Among them, the DC circuit breaker 8 is used to control the opening and closing of the first power extraction circuit, and the first DC / DC module 4 is used to control the output voltage of the second power extraction circuit.

[0033] In this embodiment, the input terminal of the DC circuit breaker 8 is connected to the energy storage unit 7, and the output terminal of the DC circuit breaker 8 is connected to the input terminal of the power conversion device 9; the second power extraction circuit includes a first DC / DC module 4, the input terminal of the first DC / DC module 4 is connected to the off-grid renewable energy power generation system 3, and the output terminal of the first DC / DC module 4 is connected to the input terminal of the power conversion device 9; the third power extraction circuit includes a rectifier bridge 6, the input terminal of the rectifier bridge 6 is connected to the power grid, and the output terminal of the rectifier bridge 6 is connected to the input terminal of the power conversion device 9.

[0034] Specifically, this application includes a battery system 1 and an energy storage converter 2. Figure 1 In this design, BMS stands for Battery Management System, EMS stands for Energy Management System, and BMS, EMS, and cloud platform are all targets to be powered. This invention uses only one power conversion device 9, which can be powered by an off-grid renewable energy generation system 3, an energy storage unit 7, and the power grid. This provides the power conversion device 9 with multiple power sources, ensuring a stable power supply to the target and preventing data loss in the energy storage system. The input voltage of the off-grid renewable energy generation system 3 can be adjusted via the first DC / DC module 4, and the input voltage of the power grid can be adjusted via the rectifier bridge 6, enabling the off-grid renewable energy... The input voltage of the power generation system 3 and the rectifier bridge 6 is higher than that of the energy storage unit 7, thus giving priority to using the off-grid renewable energy power generation system 3 and the power grid to power the power conversion device 9, further improving the available capacity of the energy storage unit 7, and can automatically adjust the off-grid renewable energy power generation system 3, the energy storage unit 7 or the power grid as the power source according to the actual working conditions; optionally, the off-grid renewable energy power generation system 3 is a photovoltaic power source; the energy storage unit 7 is a battery cluster, which includes multiple battery packs, and the multiple battery packs are used to form the energy storage unit 7 in series and parallel, and the number of battery packs can be adjusted according to the actual working needs.

[0035] In some possible embodiments, when the three power sources of the power conversion device 9 (i.e., the off-grid renewable energy generation system 3, the energy storage unit 7, and the power grid) exist simultaneously, the energy storage converter 2 controls the input voltage of the off-grid renewable energy generation system 3 to be higher than the input voltage of the power grid and the input voltage of the energy storage unit 7 through the first DC / DC module 4, ensuring that the off-grid renewable energy generation system 3 is used as the power source with priority. When the off-grid renewable energy generation system 3 exists and its power generation is sufficient to support the power output demand of the power conversion device 9, the off-grid renewable energy generation system 3 supplies power to the power conversion device 9 alone. When the off-grid renewable energy generation system 3 is missing, the energy storage converter 2 controls the rectifier bridge 6 to control... The input voltage of the power grid is higher than the input voltage of the energy storage unit 7, ensuring that the power grid is given priority in providing energy to the power conversion device 9; when both the unconnected renewable energy power generation system 3 and the power grid are unavailable, the power conversion device 9 is powered by the energy storage unit 7; the power source of the power conversion device 9 of the present invention can be switched at any time, and the unconnected renewable energy power generation system 3 and the power grid are given priority in providing power to the power conversion device 9, further ensuring a higher available capacity of the energy storage unit 7; optionally, the battery system 1 and the energy storage converter 2 can be integrated or separate, and the BMS, energy storage converter 2 and EMS communicate with each other to realize data interaction. The BMS is used for battery monitoring and protection, and the EMS is used for energy management and monitoring of the energy storage system.

[0036] In this embodiment, a charging circuit is also included. The charging circuit includes a second DC / DC module 5. The input terminal of the second DC / DC module 5 is connected to the output terminal of the first DC / DC module 4. The output terminal of the second DC / DC module 5 is simultaneously connected to the output terminal of the DC circuit breaker 8 and the input terminal of the power conversion device 9. The charging circuit also includes a DC / AC module 10. The input terminal of the second DC / DC module 5 is connected to the output terminal of the DC / AC module 10 through a DC bus 11. The output terminal of the first DC / DC module 4 is connected to the DC bus 11. The DC bus 11 is connected to the input terminal of the power conversion device 9. The input terminal of the DC / AC module 10 is connected to the power grid through a circuit breaker 12.

[0037] Specifically, the current output from the off-grid renewable energy power generation system 3 can sequentially pass through the first DC / DC module 4, the second DC / DC module 5, and the DC circuit breaker 8 to charge the energy storage unit 7, effectively utilizing energy and further ensuring the usable capacity of the energy storage unit 7; it can also be charged through the grid, further increasing the usable capacity of the energy storage unit 7; the energy storage converter 2 adopts a bipolar architecture, specifically including the first DC / DC module 4, the second DC / DC module 5, and the DC / AC module 10, for off-grid renewable energy power generation... System 3 is connected to DC bus 11 via first DC / DC module 4 to boost voltage, and is combined with second DC / DC module 5 to charge energy storage unit 7. It can also be combined with DC / AC module 10 to discharge to the grid. Energy storage unit 7 interacts with DC bus 11 through second DC / DC module 5. Second DC / DC module 5 is a step-up / step-down circuit. When energy storage unit 7 is discharging, second DC / DC module 5 is a step-up circuit. When energy storage unit 7 is charging, second DC / DC module 5 is a step-down circuit. First DC / DC module 4 is a step-up circuit. Optionally, capacitors are provided between DC buses 11.

[0038] In this embodiment, the positive terminal of the energy storage unit 7 is electrically connected to the DC circuit breaker 8 through the first fuse 13, and the negative terminal of the energy storage unit 7 is electrically connected to the DC circuit breaker 8 through the second fuse 14. When the energy storage unit 7 fails, the system can be protected by the first fuse 13 and the second fuse 14, thus ensuring the safety of the system.

[0039] In this embodiment, the positive output terminal of the second DC / DC module 5 is electrically connected to both the output terminal of the DC circuit breaker 8 and the input terminal of the power conversion device 9 via the first DC relay 15, and the negative output terminal of the second DC / DC module 5 is electrically connected to both the output terminal of the DC circuit breaker 8 and the input terminal of the power conversion device 9 via the second DC relay 16. The first DC relay 15 and the second DC relay 16 can disconnect the main circuit between the battery system 1 and the energy storage converter 2 according to actual usage requirements.

[0040] In this embodiment, the third power supply circuit is provided with a first diode, the second power supply circuit is provided with a second diode, and the first power supply circuit is provided with a third diode.

[0041] Specifically, the positive terminal of the rectifier bridge 6 is electrically connected to the power conversion device 9 via a first diode, which protects the circuit of the rectifier bridge 6; the positive terminal of the first DC / DC module 4 is electrically connected to the power conversion device 9 via a second diode, which protects the circuit of the DC bus 11; the positive terminal of the energy storage unit 7 is electrically connected to the power conversion device 9 via a third diode, which protects the circuit of the energy storage unit 7. Figure 1 In the diagram, D1 is the first diode, D2 is the second diode, and D3 is the third diode.

[0042] In this embodiment, the output voltage of the power conversion device 9 is a preset value; optionally, the preset value includes a power supply of +24V, -24V, +5V, and -5V.

[0043] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An energy storage system, characterized by, It includes a first power supply circuit, a second power supply circuit, a third power supply circuit, and a power conversion device; The output terminal of the power conversion device receives the power supply target externally, and the input terminal of the power conversion device is respectively connected to the output terminals of the first power extraction circuit, the second power extraction circuit, and the third power extraction circuit. The input terminals of the first power extraction circuit, the second power extraction circuit, and the third power extraction circuit are respectively connected to the energy storage unit, the off-grid renewable energy power generation system, and the power grid. The voltage output by the second power extraction circuit is higher than the voltage output by the third power extraction circuit, and the voltage output by the third power extraction circuit is higher than the voltage output by the first power extraction circuit. The first power supply circuit includes a DC circuit breaker; The second power supply circuit includes a first DC / DC module.

2. The energy storage system according to claim 1, characterized in that, The input terminal of the DC circuit breaker is connected to the energy storage unit, and the output terminal of the DC circuit breaker is connected to the input terminal of the power conversion device.

3. The energy storage system according to claim 1, characterized in that, The positive terminal of the energy storage unit is connected to the input terminal of the DC circuit breaker through a first fuse, and the negative terminal of the energy storage unit is connected to the input terminal of the DC circuit breaker through a second fuse.

4. The energy storage system according to claim 1, characterized in that, The input terminal of the first DC / DC module is connected to the off-grid renewable energy power generation system, and the output terminal of the first DC / DC module is connected to the input terminal of the power conversion device.

5. The energy storage system according to claim 1, characterized in that, It also includes a charging circuit, which includes a second DC / DC module. The input terminal of the second DC / DC module is connected to the output terminal of the first DC / DC module, and the output terminal of the second DC / DC module is simultaneously connected to the output terminal of the DC circuit breaker and the input terminal of the power conversion device.

6. The energy storage system according to claim 5, characterized in that, The positive output terminal of the second DC / DC module is connected to both the output terminal of the DC circuit breaker and the input terminal of the power conversion device via a first DC relay, and the negative output terminal of the second DC / DC module is connected to both the output terminal of the DC circuit breaker and the input terminal of the power conversion device via a second DC relay.

7. The energy storage system according to claim 5, characterized in that, The charging circuit further includes a DC / AC module. The input terminal of the second DC / DC module is connected to the output terminal of the DC / AC module via a DC bus. The output terminal of the first DC / DC module is connected to the DC bus. The DC bus is connected to the input terminal of the power conversion device. The input terminal of the DC / AC module is connected to the power grid via a circuit breaker.

8. The energy storage system according to claim 1, characterized in that, The third power supply circuit includes a rectifier bridge, the input terminal of which is connected to the power grid, and the output terminal of which is connected to the input terminal of the power conversion device.

9. The energy storage system according to claim 1, characterized in that, The third power supply circuit is provided with a first diode, the second power supply circuit is provided with a second diode, and the first power supply circuit is provided with a third diode.

10. The energy storage system according to claim 1, characterized in that, The output voltage of the power conversion device is a preset value.

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