Hybrid energy storage device matched with photovoltaic power generation and use method

Abstract

The invention discloses a hybrid energy storage device matched with photovoltaic power generation and a use method. The device comprises a lithium battery energy storage system, an all-vanadium redox flow battery energy storage system, a photovoltaic power generation system, a signal communication instrument, a power grid side voltage converter and a power grid side monitor. The lithium battery energy storage system is connected with the power grid side; the all-vanadium redox flow battery energy storage system is connected with the power grid side; the photovoltaic power generation system is used for supplying power to a power grid or charging the lithium battery energy storage system and the all-vanadium redox flow battery energy storage system; the signal communication instrument is used for sharing information; the power grid side voltage converter is used for converting the voltage of the power grid side and the bus side; and the power grid side monitor measures the electric quantity required by the power grid side and sends the electric quantity to the signal communication instrument. The method comprises a charging process and a discharging process. The lithium battery and the flow battery are combined, and the lithium battery is quick in response and can meet the sudden change power demand of a power grid.

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaic hybrid energy storage, and specifically relates to a hybrid energy storage device for photovoltaic power generation and a method of using the device. Background Art

[0002] Solar energy is the cleanest and most environmentally friendly energy in the new century. It is noise-free and pollution-free, has positive adjustment characteristics, and has developed rapidly. Since photovoltaic power generation is easily affected by solar light and temperature, its power generation and output power are highly random, fluctuate greatly, and are difficult to control. This makes it difficult for its power generation to match the power grid demand, and even affects its grid connection development. This brings huge safety risks to the power grid.

[0003] The current method to solve the volatility of photovoltaic power generation is not economical enough. It is mainly through the coordination of long-distance power transmission, conventional energy and photovoltaic power generation. However, due to the large volatility of photovoltaic power generation and the lack of timely coordination, it is difficult to achieve a reasonable scheduling balance, which is not economical enough. Summary of the invention

[0004] The present invention provides a hybrid energy storage device for photovoltaic power generation and a method of use, aiming to solve the problem that photovoltaic power generation has excessive volatility and cannot be coordinated in time.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A hybrid energy storage device for photovoltaic power generation, comprising a lithium battery energy storage system, an all-vanadium liquid flow battery energy storage system, a photovoltaic power generation system, a signal communication instrument, a grid-side voltage converter and a grid-side monitor; The lithium battery energy storage system is connected to the grid side to store excess electricity generated by the photovoltaic power generation system or to supply power to the grid; The all-vanadium liquid flow battery energy storage system is connected to the grid side to store excess electricity generated by the photovoltaic power generation system or to supply power to the grid; Photovoltaic power generation systems are used to supply power to the grid or charge lithium battery energy storage systems and all-vanadium liquid flow battery energy storage systems; Signal communication instrument, used to share photovoltaic power generation system, lithium battery energy storage system, all-vanadium liquid flow battery energy storage system and power grid information; A grid-side voltage converter, used to convert the voltage between the grid side and the bus side; The grid-side monitor measures the amount of electricity required on the grid side and sends it to the signal communicator.

[0006] A further improvement of the present invention is that the lithium battery energy storage system includes a lithium battery pack, a lithium battery controller, a lithium battery side voltage converter and a lithium battery side monitor; the lithium battery pack is used to store excess electrical energy generated by the photovoltaic power generation system, or to supply power to the power grid; the lithium battery controller is used to receive signals from the lithium battery side monitor and determine whether the lithium battery is performing charging and discharging operations based on the signals; the lithium battery side voltage converter is used to convert the voltage between the lithium battery side and the bus side; the lithium battery side monitor is used to measure the power of the lithium battery pack and send it to the signal communicator.

[0007] A further improvement of the present invention is that the all-vanadium liquid flow battery energy storage system includes an all-vanadium liquid flow battery system, a liquid flow battery controller, a liquid flow battery side monitor and a liquid flow battery side voltage converter; the all-vanadium liquid flow battery system is used to store excess electric energy generated by the photovoltaic power generation system, or to supply power to the power grid; the liquid flow battery controller is used to receive signals from the liquid flow battery side monitor, and determine whether the liquid flow battery is performing charging and discharging operations based on the signals; the liquid flow battery side monitor is used to measure the power of the all-vanadium liquid flow battery and send it to a signal communicator; the liquid flow battery side voltage converter is used to convert the voltages on the liquid flow battery side and the bus side.

[0008] A further improvement of the present invention is that the photovoltaic power generation system includes a photovoltaic power generation panel, a photovoltaic power generation panel side monitor and a photovoltaic power generation panel side voltage converter; the photovoltaic power generation panel is used to supply power to the power grid, or to charge the lithium battery energy storage system and the all-vanadium liquid flow battery energy storage system; the photovoltaic power generation panel side monitor is used to monitor the solar photovoltaic power generation and send it to the signal communicator; the photovoltaic power generation panel side voltage converter is used to convert the photovoltaic power generation panel side and bus voltage.

[0009] A method for using a hybrid energy storage device in conjunction with photovoltaic power generation, comprising: If the lithium battery controller and the liquid flow battery controller send charging instructions, according to the response characteristics of the lithium battery pack and the liquid flow battery, the lithium battery pack is charged first and the liquid flow battery is charged later.

[0010] A further improvement of the present invention is that when the power of the lithium battery pack is less than 50% of the capacity, the lithium battery pack is charged first, and the liquid flow battery is started at the same time. After the liquid flow battery starts, the liquid flow battery takes the opportunity to discharge; when the power of the lithium battery pack is charged to 80% of the capacity, the lithium battery pack stops working and the liquid flow battery starts charging.

[0011] A further improvement of the present invention is that when the power of the lithium battery pack is greater than 80% of the capacity, the lithium battery is charged first and the liquid flow battery is started at the same time. After the liquid flow battery is started, the liquid flow battery is charged and the lithium battery takes the opportunity to discharge. When the power is discharged to 80% of the capacity, the lithium battery stops working and the liquid flow battery continues to charge.

[0012] A method for using a hybrid energy storage device in conjunction with photovoltaic power generation, comprising: If the lithium battery controller and the liquid flow battery controller send a discharge command, according to the response characteristics of the lithium battery group and the liquid flow battery system, the lithium battery group is discharged first and the liquid flow battery is discharged later.

[0013] A further improvement of the present invention is that when the power of the liquid flow battery is greater than 80% of the capacity, the lithium battery is discharged and the liquid flow battery is started at the same time. After the liquid flow battery is started, the liquid flow battery starts to discharge. When the power of the lithium battery pack is discharged to 50% of the capacity, the lithium battery pack starts to charge. When it is charged to 80%, the lithium battery pack stops working and the liquid flow battery continues to discharge.

[0014] A further improvement of the present invention is that when the power of the liquid flow battery is less than 50% of the capacity, the lithium battery is used to discharge first, and the liquid flow battery starts to start. After the startup is completed, the liquid flow battery starts to discharge, and the lithium battery pack takes the opportunity to charge. When the power of the lithium battery pack is charged to 80% of the capacity, the lithium battery stops working and the liquid flow battery continues to discharge.

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: The present invention provides a hybrid energy storage device for photovoltaic power generation and a method of use. The hybrid energy storage device is a combination of a lithium battery and a liquid flow battery. The lithium battery has a fast response and can meet the sudden change in power demand of the power grid. The liquid flow battery has high energy storage efficiency and high energy storage density, and is suitable for large-scale energy storage. The increase of liquid flow batteries reduces the overcharge and over discharge of lithium batteries, reduces the fire risk of lithium batteries, and improves the safety of power station operation. The energy storage device can share data through signal transmission based on the balance of the power of the photovoltaic power station and the power grid, and transmit the results to the controller. The controller dispatches instructions according to the set program, and the hybrid energy storage device is charged and discharged, so that the system achieves a balance between power supply and demand.

[0016] In summary, in the face of the situation where photovoltaic power generation does not match the power grid demand, the present invention uses the monitor in the present invention to obtain the characteristics of the power generated by the photovoltaic panels and the power required by the power grid in real time, and uses the hybrid energy storage device designed in the present invention to be incorporated into the power grid to meet the power demand of the user end, so that the system power operation reaches a balanced and stable state. At the same time, when the photovoltaic power generation is greater than the power grid demand, the excess power is stored in the liquid flow battery and the lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a hybrid energy storage device for photovoltaic power generation according to the present invention.

[0018] Figure 2 Workflow diagram of a hybrid energy storage device that issues charging instructions to the controller.

[0019] Figure 3Workflow diagram of the hybrid energy storage device that issues discharge instructions to the controller.

[0020] Description of reference numerals: 1-Lithium battery pack: used to store excess electricity generated by solar energy or to supply power to the grid.

[0021] 2-Lithium battery controller: receives the signal from the lithium battery side monitor and determines whether the lithium battery is being charged or discharged based on the signal.

[0022] 3-Lithium battery side voltage converter: converts the voltage between the lithium battery side and the bus side.

[0023] 4-Lithium battery side monitor: measures the power of the lithium battery pack and sends it to the signal communicator.

[0024] 5-All-vanadium liquid flow battery system: used to store excess electricity generated by solar energy or to supply power to the grid.

[0025] 6-Liquid flow battery controller: receives the signal from the monitor on the liquid flow battery side, and determines whether the liquid flow battery is performing charging and discharging operations based on the signal.

[0026] 7-Flow battery side monitor: measures the power of the all-vanadium flow battery and sends it to the signal communicator.

[0027] 8-Liquid flow battery side voltage converter: converts the voltage between the liquid flow battery side and the bus side.

[0028] 9- Photovoltaic panels: Photovoltaic modules generate electricity to power the grid or charge hybrid energy storage devices.

[0029] 10- Photovoltaic panel side monitor: used to monitor the power generation of solar photovoltaic and send it to the signal communicator.

[0030] 11-Voltage converter on photovoltaic panel side: converts the voltage on photovoltaic panel side and bus voltage.

[0031] 12-Signal communicator: used to share photovoltaic panels, lithium batteries, flow batteries and power grid information.

[0032] 13-Grid side voltage converter: converts the voltage between the grid side and the bus side.

[0033] 14-Grid side monitor: measures the amount of electricity required on the grid side and sends it to the signal communicator.

[0034] 15-Grid: The user side of the system. DETAILED DESCRIPTION

[0035] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0038] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0040] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0041] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0042] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0043] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0044] Example 1 like Figure 1 As shown, a hybrid energy storage device for photovoltaic power generation provided in this embodiment includes a lithium battery energy storage system, an all-vanadium liquid flow battery energy storage system, a photovoltaic power generation system, a signal communication instrument 12, a grid-side voltage converter 13 and a grid-side monitor 14; The lithium battery energy storage system is connected to the grid side to store excess electricity generated by the photovoltaic power generation system or to supply power to the grid; The all-vanadium liquid flow battery energy storage system is connected to the grid side to store excess electricity generated by the photovoltaic power generation system or to supply power to the grid; Photovoltaic power generation systems are used to supply power to the grid or charge lithium battery energy storage systems and all-vanadium liquid flow battery energy storage systems; Signal communication instrument, used to share photovoltaic power generation system, lithium battery energy storage system, all-vanadium liquid flow battery energy storage system and power grid information; A grid-side voltage converter, used to convert the voltage between the grid side and the bus side; The grid-side monitor measures the amount of electricity required on the grid side and sends it to the signal communicator.

[0045] In this embodiment, the lithium battery energy storage system includes a lithium battery pack 1, a lithium battery controller 2, a lithium battery side voltage converter 3 and a lithium battery side monitor 4; the lithium battery pack 1 is used to store excess electrical energy generated by the photovoltaic power generation system, or to supply power to the power grid; the lithium battery controller 2 is used to receive signals from the lithium battery side monitor and determine whether the lithium battery is performing charging and discharging operations based on the signals; the lithium battery side voltage converter 3 is used to convert the voltage between the lithium battery side and the bus side; the lithium battery side monitor 4 is used to measure the power of the lithium battery pack and send it to the signal communicator.

[0046] In this embodiment, the all-vanadium liquid flow battery energy storage system includes an all-vanadium liquid flow battery system 5, a liquid flow battery controller 6, a liquid flow battery side monitor 7 and a liquid flow battery side voltage converter 8; the all-vanadium liquid flow battery system 5 is used to store excess electric energy generated by the photovoltaic power generation system, or to supply power to the power grid; the liquid flow battery controller 6 is used to receive signals from the liquid flow battery side monitor, and determine whether the liquid flow battery is performing charging and discharging operations based on the signals; the liquid flow battery side monitor 7 is used to measure the power of the all-vanadium liquid flow battery and send it to the signal communicator; the liquid flow battery side voltage converter 8 is used to convert the voltage between the liquid flow battery side and the bus side.

[0047] In this embodiment, the photovoltaic power generation system includes a photovoltaic panel 9, a photovoltaic panel side monitor 10 and a photovoltaic panel side voltage converter 11; the photovoltaic panel 9 is used to supply power to the power grid, or to charge the lithium battery energy storage system and the all-vanadium liquid flow battery energy storage system; the photovoltaic panel side monitor 10 is used to monitor the solar photovoltaic power generation and send it to the signal communicator; the photovoltaic panel side voltage converter 11 is used to convert the photovoltaic panel side and bus voltage.

[0048] The hybrid energy storage device of the present invention is suitable for photovoltaic power stations with fluctuations. The monitors and controllers of the present invention can share information. The monitors monitor the power demand of the power grid and the power generation capacity of the photovoltaic panels. The controller determines whether the hybrid energy storage device is charged or discharged (for example, when the power generated by the photovoltaic panels is less than the power required by the power grid, the energy storage device is in the discharge mode, the liquid flow battery system converts chemical energy into electrical energy, and the lithium battery pack outputs the stored electrical energy). The charging and discharging sequence of the lithium battery and the liquid flow battery in the hybrid energy storage device is determined according to the power of the lithium battery and the liquid flow battery in the hybrid energy storage device, so that the power grid is in a safe and stable operating state.

[0049] In this embodiment, the working control method is as follows: the lithium battery side monitor 4, the flow battery side monitor 7, the photovoltaic panel side monitor 10 and the grid side monitor 14 respectively monitor the real-time power generation of the photovoltaic panel, the power required by the grid, the power stored in the lithium battery and the power stored in the flow battery, the signal communicator 12 shares the information collected by the monitor, the lithium battery side voltage converter 2 and the flow battery controller 6 make judgments based on the information shared by the communication device, and issue instructions for charging or discharging the hybrid energy storage device. The cycle continues to achieve a balance between power supply and use of the system.

[0050] According to the response characteristics of lithium battery packs and flow batteries, lithium battery packs have a fast response speed and flow batteries have a large capacity, which are suitable for large-scale energy storage. In the face of short-term sudden power demand, only lithium batteries are needed to work; in the face of long-term high-power power demand, lithium batteries and flow batteries work at the same time. At the beginning, lithium batteries mainly perform auxiliary functions to improve the response of the power grid. As the output power of the flow battery increases, the output power of the lithium battery decreases until the lithium battery stops working. In order to increase the service life of lithium batteries, the capacity of the lithium battery pack during operation needs to be maintained at 50%-80%. If it is a long-term high-power power demand, the working state of the hybrid energy storage device is as follows.

[0051] Example 2 like Figure 2 As shown, the present embodiment provides a method for using a hybrid energy storage device in conjunction with photovoltaic power generation, including: if the lithium battery controller 2 and the flow battery controller 6 issue a charging instruction, the steps of charging the hybrid energy storage device are as follows: According to the response characteristics of the lithium battery pack and the flow battery, the lithium battery pack is charged first and the flow battery is charged later.

[0052] Charging state 1: When the power of the lithium battery pack is less than 50% of the capacity, the lithium battery pack is charged first, and the flow battery is started at the same time. After the start-up of the flow battery is completed, the flow battery takes the opportunity to discharge; when the power of the lithium battery pack is charged to 80% of the capacity, the lithium battery pack stops working and the flow battery starts charging.

[0053] Charging state 2: When the power of the lithium battery pack is greater than 80% of the capacity, the lithium battery is charged first, and the flow battery is started at the same time. After the flow battery is started, the flow battery is charged and the lithium battery takes the opportunity to discharge. When the capacity is discharged to 80%, the lithium battery stops working and the flow battery continues to charge.

[0054] Example 3 like Figure 3 As shown, the present embodiment provides a method for using a hybrid energy storage device in conjunction with photovoltaic power generation, including: if the lithium battery controller 2 and the flow battery controller 6 issue a discharge instruction, the steps of the hybrid energy storage device discharging state are as follows: According to the response characteristics of the lithium battery pack and the flow battery system, the lithium battery pack is discharged first and the flow battery is discharged later.

[0055] Discharge state 1: When the charge of the flow battery is greater than 80% of the capacity, the lithium battery is discharged and the flow battery is started at the same time. After the start-up of the flow battery is completed, the flow battery starts to discharge. When the charge of the lithium battery pack is discharged to 50% of the capacity, the lithium battery pack starts to charge. When the charge reaches 80%, the lithium battery pack stops working and the flow battery continues to discharge. Discharge state 2: When the charge of the flow battery is less than 50% of its capacity, the lithium battery is used to discharge first, and the flow battery starts to start. After the startup is completed, the flow battery starts to discharge, and the lithium battery pack takes the opportunity to charge. When the lithium battery pack is charged to 80% of its capacity, the lithium battery stops working and the flow battery continues to discharge.

[0056] The above-mentioned charging and discharging states are decided based on the power generation of the photovoltaic panels and the power required by the power grid.

[0057] In summary, the hybrid energy storage device and the method of use of the present invention are suitable for photovoltaic power stations with fluctuations. The present invention can control the charging and discharging of the hybrid energy storage device according to the balance between the power generation of the photovoltaic power station and the power required by the power grid; the hybrid energy storage device of the present invention can release the stored electric energy during the peak period of power demand to reduce the load pressure on the power grid; and store electric energy during the low period of power demand for emergency use; the present invention combines the advantages of lithium batteries and flow batteries to improve battery utilization.

[0058] In addition, the hybrid energy storage device provided by the present invention can timely respond to the power demand of the system composed of photovoltaic power generation and power grid; the hybrid energy storage device can cope with the phenomenon that photovoltaic power generation is insufficient to meet the power grid demand; in areas where time-of-use electricity prices are implemented, the hybrid energy storage device can be introduced to effectively reduce electricity costs by using photovoltaic power and peak-valley time shifting. Therefore, the present invention can reduce the phenomenon of abandoned light and improve the utilization rate of photovoltaic power generation.

[0059] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0060] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A hybrid energy storage device for photovoltaic power generation, characterized in that: Including lithium battery energy storage system, all-vanadium liquid flow battery energy storage system, photovoltaic power generation system, signal communication instrument, grid-side voltage converter and grid-side monitor; The lithium battery energy storage system is connected to the grid side to store excess electricity generated by the photovoltaic power generation system or to supply power to the grid; The all-vanadium liquid flow battery energy storage system is connected to the grid side to store excess electricity generated by the photovoltaic power generation system or to supply power to the grid; Photovoltaic power generation systems are used to supply power to the grid or charge lithium battery energy storage systems and all-vanadium liquid flow battery energy storage systems; Signal communication instrument, used to share photovoltaic power generation system, lithium battery energy storage system, all-vanadium liquid flow battery energy storage system and power grid information; A grid-side voltage converter, used to convert the voltage between the grid side and the bus side; The grid-side monitor measures the amount of electricity required on the grid side and sends it to the signal communicator.

2. A hybrid energy storage device for photovoltaic power generation according to claim 1, characterized in that: The lithium battery energy storage system includes a lithium battery pack, a lithium battery controller, a lithium battery side voltage converter and a lithium battery side monitor; the lithium battery pack is used to store excess electrical energy generated by the photovoltaic power generation system, or to supply power to the power grid; the lithium battery controller is used to receive signals from the lithium battery side monitor and determine whether the lithium battery is being charged or discharged based on the signals; the lithium battery side voltage converter is used to convert the voltage between the lithium battery side and the bus side; the lithium battery side monitor is used to measure the power of the lithium battery pack and send it to the signal communicator.

3. A hybrid energy storage device for photovoltaic power generation according to claim 2, characterized in that: The all-vanadium liquid flow battery energy storage system includes an all-vanadium liquid flow battery system, a liquid flow battery controller, a liquid flow battery side monitor and a liquid flow battery side voltage converter; the all-vanadium liquid flow battery system is used to store excess electric energy generated by the photovoltaic power generation system, or to supply power to the power grid; the liquid flow battery controller is used to receive signals from the liquid flow battery side monitor, and determine whether the liquid flow battery is performing charging and discharging operations based on the signals; the liquid flow battery side monitor is used to measure the power of the all-vanadium liquid flow battery and send it to the signal communicator; the liquid flow battery side voltage converter is used to convert the voltage between the liquid flow battery side and the bus side.

4. A hybrid energy storage device for photovoltaic power generation according to claim 3, characterized in that: The photovoltaic power generation system includes photovoltaic panels, photovoltaic panel side monitors and photovoltaic panel side voltage converters; photovoltaic panels are used to supply power to the grid, or charge lithium battery energy storage systems and all-vanadium liquid flow battery energy storage systems; photovoltaic panel side monitors are used to monitor the power generation of solar photovoltaics and send it to a signal communicator; photovoltaic panel side voltage converters are used to convert photovoltaic panel side and bus voltages.

5. The method for using a hybrid energy storage device in combination with photovoltaic power generation as claimed in claim 4, characterized in that: include: If the lithium battery controller and the liquid flow battery controller send charging instructions, according to the response characteristics of the lithium battery pack and the liquid flow battery, the lithium battery pack is charged first and the liquid flow battery is charged later.

6. The method for using a hybrid energy storage device in conjunction with photovoltaic power generation according to claim 5, characterized in that: When the power of the lithium battery pack is less than 50% of its capacity, the lithium battery pack is charged first, and the flow battery is started at the same time. After the start-up of the flow battery is completed, the flow battery takes the opportunity to discharge. When the power of the lithium battery pack is charged to 80% of its capacity, the lithium battery pack stops working and the flow battery starts charging.

7. The method for using a hybrid energy storage device in conjunction with photovoltaic power generation according to claim 5, characterized in that: When the power of the lithium battery pack is greater than 80% of its capacity, the lithium battery is charged first and the flow battery is started at the same time. After the flow battery is started and charged, the lithium battery takes the opportunity to discharge. When the capacity is discharged to 80%, the lithium battery stops working and the flow battery continues to charge.

8. The method for using a hybrid energy storage device in combination with photovoltaic power generation as claimed in claim 4, characterized in that: include: If the lithium battery controller and the liquid flow battery controller send a discharge command, according to the response characteristics of the lithium battery group and the liquid flow battery system, the lithium battery group is discharged first and the liquid flow battery is discharged later.

9. The method for using a hybrid energy storage device in conjunction with photovoltaic power generation according to claim 8, characterized in that: When the charge of the flow battery is greater than 80% of its capacity, the lithium battery discharges and the flow battery starts at the same time. After the start-up of the flow battery is completed, the flow battery begins to discharge. When the lithium battery pack is discharged to 50% of its capacity, the lithium battery pack begins to charge. When it is charged to 80%, the lithium battery pack stops working and the flow battery continues to discharge.

10. The method for using a hybrid energy storage device in conjunction with photovoltaic power generation according to claim 8, characterized in that: When the charge of the flow battery is less than 50% of its capacity, the lithium battery is used to discharge first, and the flow battery starts to start. After the startup is completed, the flow battery starts to discharge, and the lithium battery pack takes the opportunity to charge. When the lithium battery pack is charged to 80% of its capacity, the lithium battery stops working and the flow battery continues to discharge.

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