Small-sized flow battery single battery assembly and small-sized flow battery single battery

Abstract

A first sealing gasket frame, an electrode frame, a second sealing gasket frame, a bipolar plate, a liquid inlet and outlet plate and an end plate are sequentially and fixedly laminated on the left side and the right side of an ion exchange membrane from inside to outside by taking the ion exchange membrane as a center; the first sealing gasket frame, the electrode frame and the second sealing gasket frame are embedded with an electrode, and one side, facing the ion exchange membrane, of the liquid inlet and outlet plate is recessed inwards and is embedded with a collector plate. The small-sized flow battery single battery assembly can reduce material waste, and is simple in structure, simple, rapid and flexible to assemble, applicable to testing of electrode materials with different thicknesses, convenient to disassemble and assemble and low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of liquid flow batteries, and in particular relates to a small liquid flow battery single cell assembly and a small liquid flow battery single cell. Background Art

[0002] Liquid flow battery is an emerging energy storage battery, which consists of a battery stack unit, electrolyte, electrolyte storage and supply unit, and management and control unit. As a new type of large-scale electrochemical energy storage battery, liquid flow battery is different from batteries that usually use solid material electrodes or gas electrodes. Its active material is a flowing electrolyte solution, and the positive and negative electrolytes are circulated separately. Its most notable feature is large-scale power storage and independent design of power and capacity. Liquid flow battery is a high-performance battery with high capacity, wide application field (environment), and long cycle life.

[0003] The stack of a flow battery is mainly composed of an ion exchange membrane, an electrode frame with electrodes embedded therein, a bipolar plate, etc. The selection of materials such as ion exchange membranes, electrodes, and bipolar plates will directly affect the electrical performance of the flow battery. Normal flow batteries are large in size and difficult to assemble. Electrical performance testing after assembly will seriously waste raw materials and manpower. For this reason, in the prior art, the normal stack structure is usually reduced in size by a certain proportion for material testing. As the size is reduced, the difficulty of assembly increases further. In order to reduce the difficulty of assembly, the stack can be further simplified to prepare a flow battery cell. However, as the size is reduced and the structure is simplified, it becomes increasingly difficult to ensure the sealing during assembly. Therefore, it is difficult to achieve a very small size. Moreover, a well-designed flow battery cell is basically only suitable for testing materials of a selected thickness. When the thickness of the test material is not appropriate, the probability of leakage increases significantly, and the versatility is poor. Summary of the invention

[0004] The object of the present invention is to provide a small-sized liquid flow battery single cell assembly and a small-sized liquid flow battery single cell which are easy, fast, flexible to assemble and have good sealing performance.

[0005] Another object of the present invention is to provide an application of the above-mentioned small liquid flow battery cell in the performance test of battery stack materials.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a small-scale liquid flow battery single cell assembly, which takes an ion exchange membrane as the center, and a first sealing gasket frame, an electrode frame, a second sealing gasket frame, a bipolar plate, an inlet and outlet liquid plate and an end plate are laminated and fixedly arranged on the left and right sides of the ion exchange membrane from the inside to the outside, and an electrode is embedded in the first sealing gasket frame, the electrode frame and the second sealing gasket frame, and the side of the inlet and outlet liquid plate facing the ion exchange membrane is concave inward and embedded with a current collecting plate. Among them, the side of the electrode frame away from the ion exchange membrane is provided with an electrolyte drainage area recessed inward from its surface, and the electrolyte drainage area includes a first electrolyte drainage area arranged at the lower part of the electrode frame and a second electrolyte drainage area arranged at the upper part of the electrode frame. The lower part of the small liquid flow battery single cell assembly is provided with a positive electrode electrolyte inlet flow channel and a negative electrode electrolyte inlet flow channel extending in the left and right directions, and the upper part of the small liquid flow battery single cell assembly is provided with a positive electrode electrolyte outlet flow channel and a negative electrode electrolyte outlet flow channel extending in the left and right directions. The left end of the positive electrolyte inlet flow channel The positive electrode electrolyte outlet channel is connected to the outside world, and the right end is connected to the first electrolyte drainage area of ​​the electrode frame located on the left side of the ion exchange membrane. The right end of the negative electrode electrolyte inlet channel is connected to the outside world, and the left end is connected to the first electrolyte drainage area of ​​the electrode frame located on the right side of the ion exchange membrane. The left end of the positive electrode electrolyte outlet channel is connected to the outside world, and the right end is connected to the second electrolyte drainage area of ​​the electrode frame located on the left side of the ion exchange membrane. The right end of the negative electrode electrolyte outlet channel is connected to the outside world, and the left end is connected to the second electrolyte drainage area of ​​the electrode frame located on the right side of the ion exchange membrane.

[0007] In an embodiment of the present invention, the sum of the thicknesses of the first sealing gasket frame, the electrode frame and the second sealing gasket frame is 1 to 1.2 times the thickness of the electrode. Preferably, the thickness of the electrode is substantially equal to the sum of the thicknesses of the first sealing gasket frame, the electrode frame and the second sealing gasket frame.

[0008] In the embodiment of the present invention, the first sealing gasket frame, the electrode frame and the second sealing gasket frame are respectively a roundabout structure with a cavity, and the cavities of the first sealing gasket frame, the electrode frame and the second sealing gasket frame together constitute a accommodating cavity for the electrode.

[0009] In the embodiment of the present invention, the number of the first sealing gasket frame and / or the second sealing gasket frame is one or more, and the thicknesses of the plurality of the first sealing gasket frames and / or the second sealing gasket frames are equal or different.

[0010] In the embodiment of the present invention, electrodes of different thicknesses can be quickly adapted by replacing first sealing gasket frames and / or second sealing gasket frames of different thicknesses, or the thickness of the electrode can be matched by using multiple first sealing gasket frames and / or the second sealing gasket frames at the same time.

[0011] In an embodiment of the present invention, the lower frames of the end plate, the inlet and outlet plate, the bipolar plate, and the second sealing gasket frame are respectively provided with inlet through holes, and the upper frames of the end plate, the inlet and outlet plate, the bipolar plate, and the second sealing gasket frame are respectively provided with outlet through holes. Among them, the inlet through holes of the end plate, the inlet and outlet plate, the bipolar plate, and the second sealing gasket frame located on the left side of the ion exchange membrane are connected to form the positive electrolyte inlet flow channel, the inlet through holes of the end plate, the inlet and outlet plate, the bipolar plate, and the second sealing gasket frame located on the right side of the ion exchange membrane are connected to form the negative electrolyte inlet flow channel, the outlet through holes of the end plate, the inlet and outlet plate, and the second sealing gasket frame located on the left side of the ion exchange membrane are connected to form the positive electrolyte outlet flow channel, and the outlet through holes of the end plate, the inlet and outlet plate, and the second sealing gasket frame located on the right side of the ion exchange membrane are connected to form the negative electrolyte outlet flow channel.

[0012] In the embodiment of the present invention, the liquid inlet through hole of the end plate and the liquid inlet through hole of the liquid inlet and outlet plate are connected with a pagoda joint, and the liquid outlet through hole of the end plate and the liquid outlet through hole of the liquid inlet and outlet plate are connected with a pagoda joint. Preferably, the liquid inlet through hole and the liquid outlet through hole on the liquid inlet and outlet plate are provided with internal threads to facilitate screwing on a pagoda joint of suitable size.

[0013] According to some specific embodiments of the present invention, the electrolyte drainage area includes a guide channel and a distribution channel, the guide channel extends along the symmetry axis of the cavity of the electrode frame, and the width of the distribution channel gradually decreases from the inner frame of the electrode frame to the guide channel.

[0014] In an embodiment of the present invention, positioning through holes for positioning and installing screws are respectively provided at the four corners of the ion exchange membrane, the first sealing gasket frame, the electrode frame, the second sealing gasket frame, the bipolar plate, the inlet and outlet plates and the end plate, and the small liquid flow battery single cell assembly also includes screws for laminating and fixing the ion exchange membrane, the first sealing gasket frame, the electrode frame, the second sealing gasket frame, the bipolar plate, the inlet and outlet plates and the end plate.

[0015] In an embodiment of the present invention, a sealing ring is provided between the liquid inlet through hole of the liquid inlet and outlet plate and the liquid inlet through hole of the bipolar plate.

[0016] In an embodiment of the present invention, a sealing ring is provided between the liquid outlet through hole of the liquid inlet and outlet plate and the liquid outlet through hole of the bipolar plate.

[0017] In the embodiment of the present invention, the electrode frame is made of PP, PE or PVC.

[0018] In the embodiment of the present invention, the material of the liquid inlet and outlet plates is PP, PE or PVC.

[0019] In the embodiment of the present invention, the material of the end plate is aluminum alloy, stainless steel or carbon steel.

[0020] In an embodiment of the present invention, the first sealing gasket and the second sealing gasket are independently made of rubber or silicone.

[0021] In an embodiment of the present invention, the length and width of the ion exchange membrane, the first sealing gasket frame, the electrode frame, the second sealing gasket frame, the inlet and outlet plates and the end plates are independently 50-150 mm.

[0022] The second aspect of the present invention also provides a liquid flow battery cell, wherein the liquid flow battery cell comprises the above-mentioned small liquid flow battery cell assembly.

[0023] Furthermore, the liquid flow battery cell also includes a positive electrode electrolyte storage unit for storing positive electrode electrolyte, a negative electrode electrolyte storage unit for storing negative electrode electrolyte and a small electrolyte circulation system which are conventionally used in the art, and are connected and assembled into a liquid flow battery cell with the above-mentioned small liquid flow battery cell assembly according to the existing technology in the art, which will not be described in detail in this article.

[0024] The liquid flow battery cell of the present invention can be used for performance testing of battery stack materials, such as for performance testing of ion exchange membranes, electrodes or bipolar plates, which facilitates early material screening and reduces material waste.

[0025] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The small-scale liquid flow battery single cell assembly of the present invention can have good sealing performance even in a smaller size, and can reduce material waste when used for battery stack material screening or performance testing. The small-scale liquid flow battery single cell assembly of the present invention has a simple structure, and is easy, fast and flexible to assemble. It can be applied to the testing of electrode materials of different thicknesses, is easy to disassemble and assemble, and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the three-dimensional structure of a single cell assembly of a flow battery in Example 1; Figure 2 It is a schematic diagram of the three-dimensional structure of the single cell assembly of the flow battery of Example 1 from another viewing angle; Figure 3 for Figure 1 Schematic diagram of the main structure; Figure 4 For along Figure 3 Schematic diagram of the three-dimensional cross-sectional structure of AA; Figure 5 For along Figure 3 Schematic diagram of the cross-sectional structure of AA; Figure 6 for Figure 1 Side view of Figure 7 for Figure 1 A top view of Figure 8 It is a schematic diagram of the three-dimensional structure of the electrode frame in the single cell assembly of the flow battery of Example 1; Fig. 9 for Figure 8 Schematic diagram of the main structure; Fig.10 for Figure 8 A rear view structural diagram of ; Fig.11 It is a schematic diagram of the three-dimensional structure of the liquid inlet and outlet plates in the single cell assembly of the liquid flow battery of Example 1; Fig.12 for Fig.11 Schematic diagram of the main structure; Fig.13 For along Fig.12 Schematic diagram of the cross-sectional structure of the middle BB; Fig.14 for Fig.11 A rear view structural diagram of ; Fig.15 for Fig.11 A side view structural schematic diagram of; Fig.16 It is a schematic diagram of the three-dimensional structure of the end plate in the single cell assembly of the flow battery of Example 1; Fig.17 It is a schematic diagram of the three-dimensional structure of the first sealing gasket frame in the liquid flow battery single cell assembly of Example 1; Fig.18 Schematic diagram of the three-dimensional structure of the second sealing gasket frame in the liquid flow battery single cell assembly of Example 1.

[0027] In the above figure, 1. ion exchange membrane; 2. first sealing gasket frame; 3. electrode frame; 31. guide flow channel; 32. distribution flow channel; 4. second sealing gasket frame; 5. bipolar plate; 6. current collecting plate; 7. inlet and outlet plates; 8. end plate; 9. electrode; 10. pagoda joint; 111. positive electrolyte inlet flow channel; 112. positive electrolyte outlet flow channel; 113. negative electrolyte inlet flow channel; 114. negative electrolyte outlet flow channel; 13. positioning through hole; 121. liquid inlet through hole; 122. liquid outlet through hole. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings.

[0029] 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 embodiments of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0030] In the description of the present invention, it should be understood that the terms "left", "right", "upper" and "lower" are based on Figure 5 The orientation or position relationship shown. "Inside" refers to the position close to the center of the flow battery cell, and "outside" refers to the position away from the center of the flow battery cell. The above-mentioned directional words are only used to facilitate the description of the embodiments of the present invention and simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present invention.

[0031] In the description of the present invention, unless otherwise clearly specified and limited, the terms "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 one. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0032] In the description of the present application, it should be understood that 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined. Example 1

[0033] The present embodiment provides a small liquid flow battery cell, which includes a small liquid flow battery cell assembly, a positive electrode electrolyte storage unit storing a positive electrode electrolyte, a negative electrode electrolyte storage unit storing a negative electrode electrolyte, and a small electrolyte circulation system.

[0034] Specifically, Figures 1 to 18As shown, the small liquid flow battery single cell assembly of this embodiment is centered on the ion exchange membrane 1, and the first sealing gasket frame 2, electrode frame 3, second sealing gasket frame 4, bipolar plate 5, inlet and outlet liquid plate 7 and end plate 8 are laminated and fixed in sequence from the inside to the outside on the left and right sides of the ion exchange membrane 1, and an electrode 9 is embedded in the first sealing gasket frame 2, the electrode frame 3 and the second sealing gasket frame 4. The side of the inlet and outlet liquid plate 7 facing the ion exchange membrane 1 is recessed inward and embedded with a current collecting plate 6. The side of the electrode frame 3 facing away from the ion exchange membrane 1 is provided with an electrolyte drainage area recessed inward from its surface, and the electrolyte drainage area includes a first electrolyte drainage area arranged at the lower part of the electrode frame 3 and a second electrolyte drainage area arranged at the upper part of the electrode frame 3. The lower part of the small-scale liquid flow battery single cell assembly of this embodiment is provided with a positive electrode electrolyte inlet flow channel 111 and a negative electrode electrolyte inlet flow channel 113 extending in the left-right direction, and the upper part of the small-scale liquid flow battery single cell assembly is provided with a positive electrode electrolyte outlet flow channel 112 and a negative electrode electrolyte outlet flow channel 114 extending in the left-right direction. The left end of the positive electrode electrolyte inlet flow channel 111 is connected to the outside, and the right end is connected to the first electrolyte drainage area of ​​the electrode frame 3 located on the left side of the ion exchange membrane 1. The right end of the negative electrolyte inlet flow channel 113 is connected to the outside world, and the left end is connected to the first electrolyte drainage area of ​​the electrode frame 3 located on the right side of the ion exchange membrane 1. The left end of the positive electrolyte outlet flow channel 112 is connected to the outside world, and the right end is connected to the second electrolyte drainage area of ​​the electrode frame 3 located on the left side of the ion exchange membrane 1. The right end of the negative electrolyte outlet flow channel 114 is connected to the outside world, and the left end is connected to the second electrolyte drainage area of ​​the electrode frame 3 located on the right side of the ion exchange membrane 1.

[0035] In this embodiment, the thickness of the electrode 9 is approximately equal to the sum of the thicknesses of the first sealing gasket frame 2, the electrode frame 3, and the second sealing gasket frame 4. The first sealing gasket frame 2, the electrode frame 3, and the second sealing gasket frame 4 are respectively a round-shaped structure with a cavity, and the cavities of the first sealing gasket frame 2, the electrode frame 3, and the second sealing gasket frame 4 together constitute the accommodating cavity of the electrode. In this embodiment, the lower frame of the end plate 8, the inlet and outlet plate 7, the bipolar plate 5, and the second sealing gasket frame 4 are respectively provided with a liquid inlet through hole 121, and the upper frame of the end plate 8, the inlet and outlet plate 7, the bipolar plate 5, and the second sealing gasket frame 4 are respectively provided with a liquid outlet through hole 122. The liquid inlet through holes 121 of the end plate 8, the inlet and outlet plate 7, the bipolar plate 5, and the second sealing gasket frame 4 on the left side of the ion exchange membrane 1 are connected to form a positive electrolyte inlet flow channel 111. The end plate 8, the inlet and outlet plate 7, the bipolar plate 5, and the inlet through hole 121 of the second sealing gasket frame 4 located on the right side of the ion exchange membrane 1 are connected to form a negative electrolyte inlet flow channel 113. The end plate 8, the inlet and outlet plate 7, and the outlet through hole 122 of the second sealing gasket frame 4 located on the left side of the ion exchange membrane 1 are connected to form a positive electrolyte outlet flow channel 112. The end plate 8, the inlet and outlet plate 7, and the outlet through hole 122 of the second sealing gasket frame 4 located on the right side of the ion exchange membrane 1 are connected to form a negative electrolyte outlet flow channel 114. In this embodiment, the liquid inlet through hole 121 of the end plate 8 and the liquid inlet through hole 121 of the liquid inlet and outlet plate 7 are connected with a pagoda connector 10, and the liquid outlet through hole 122 of the end plate 8 and the liquid outlet through hole 122 of the liquid inlet and outlet plate 7 are connected with a pagoda connector 10. The liquid inlet through hole 121 and the liquid outlet through hole 122 on the liquid inlet and outlet plate 7 are provided with internal threads, which are convenient for screwing on the pagoda connector 10 of suitable size. In this embodiment, the electrolyte drainage area of ​​the electrode frame 3 includes a guide flow channel 31 and a distribution flow channel 32, the guide flow channel 31 extends along the center line direction of the cavity of the electrode frame 3, and the width of the distribution flow channel 32 gradually decreases from the inner frame of the electrode frame 3 to the guide flow channel 31. In this embodiment, the corners of the ion exchange membrane 1, the first sealing gasket frame 2, the electrode frame 3, the second sealing gasket frame 4, the bipolar plate 5, the inlet and outlet plates 7 and the end plate 8 are respectively provided with positioning holes 13 for positioning and installing screws. The small liquid flow battery single cell assembly of this embodiment also includes screws for laminating and fixing the ion exchange membrane 1, the first sealing gasket frame 2, the electrode frame 3, the second sealing gasket frame 4, the bipolar plate 5, the inlet and outlet plates 7 and the end plate 8. In the embodiment of the present invention, a sealing ring is provided between the liquid inlet through hole of the inlet and outlet plate 7 and the liquid inlet through hole 121 of the bipolar plate 5, and a sealing ring is also provided between the liquid outlet through hole 122 of the inlet and outlet plate 7 and the liquid outlet through hole 122 of the bipolar plate 5. In this embodiment, the material of the electrode frame 3 and the inlet and outlet plates 7 is PVC, the material of the end plate 8 is aluminum alloy, the material of the first sealing gasket frame 2 and the second sealing gasket frame 4 is silica gel, the bipolar plate 5 is a graphite plate, and the electrode 9 is a graphite felt electrode.

[0036] The performance of two commercially available ion exchange membranes were compared by testing the small liquid flow battery cell of this embodiment and the traditional liquid flow battery cell. The ion exchange membrane of brand 1 (Kerun) is a perfluorosulfonic acid proton exchange membrane with a thickness of 0.05 mm, which comes from Suzhou Kerun New Materials Co., Ltd., item number N-212; the ion exchange membrane of brand 2 (Hancheng) is a perfluorosulfonic acid proton exchange membrane with a thickness of 0.06 mm, which comes from Hancheng New Materials Technology (Shanghai) Co., Ltd.

[0037] The test small flow battery single cell A, the single cell assembly specifications are as follows: The specifications of the end plate 8 are 90mm×80mm×10mm, the specifications of the inlet and outlet plates 7 are 74mm×74mm×20mm, the specifications of the electrode frame 3 are 70mm×70mm×2mm, the specifications of the bipolar plate 5 are 70mm×70mm×1mm, the specifications of the electrode 9 are 50mm×50mm×4mm, the specifications of the first sealing gasket frame 2 and the second sealing gasket frame 4 are 70mm×70mm×1mm, and the ion exchange membrane of brand 1 with a cutting specification of 70mm×70mm×0.05mm is assembled into Figure 1 The structure shown.

[0038] The test small flow battery single cell B, the single cell assembly specifications are as follows: The specifications of the end plate 8 are 90mm×80mm×10mm, the specifications of the inlet and outlet plates 7 are 74mm×74mm×20mm, the specifications of the electrode frame 3 are 70mm×70mm×2mm, the specifications of the bipolar plate 5 are 70mm×70mm×1mm, the specifications of the electrode 9 are 50mm×50mm×4mm, the specifications of the first sealing gasket frame 2 and the second sealing gasket frame 4 are 70mm×70mm×1mm, and the ion exchange membrane of brand 2 with a cutting specification of 70mm×70mm×0.06mm is assembled into Figure 1 The structure shown.

[0039] Tested conventional flow battery cell A: The flow battery cell A is manufactured with reference to the flow battery cell structure of patent CN111261895B. The specifications of the bipolar plate are 730mm×280mm×1mm, the specifications of the electrode are 690mm×240mm×4mm, the specifications of the electrode frame are 730mm×280mm×3mm, and the ion exchange membrane is a brand 1 ion exchange membrane with specifications of 710mm×260mm×0.05mm.

[0040] Tested conventional flow battery cell B:

[0041] The liquid flow battery cell B is manufactured with reference to the liquid flow battery cell structure of patent CN111261895B. The specifications of the bipolar plate are 730mm×280mm×1mm, the specifications of the electrode are 690mm×240mm×4mm, the specifications of the electrode frame are 730mm×280mm×3mm, and the ion exchange membrane is a brand 2 ion exchange membrane with a specification of 710mm×260mm×0.06mm.

[0042] After assembling the above-mentioned single cell components, connect them to a small electrolyte circulation system, start the peristaltic pump or magnetic pump, circulate the electrolyte, circulate for 1 hour, allow the electrolyte to fully soak the electrodes, and observe whether there is leakage. If no leakage is found, the charge and discharge test instrument can be turned on to start the test. The performance test results of the ion exchange membrane of brand 1 are shown in Table 1, and the performance test results of the ion exchange membrane of brand 2 are shown in Table 2.

[0043]

[0044] The single cell was tested and assembled. It took about 30 minutes to assemble a single cell of a conventional flow battery. It was assembled four times during the test, and leakage occurred twice, requiring reassembly. The single cell of the present invention took about 10 minutes to assemble. It was assembled twice during this test, and no leakage occurred.

[0045] Traditional flow battery cells are prone to leakage during assembly, causing electrolyte to leak out of the battery or electrolytes in the positive and negative electrodes to cross-link, thus affecting test results. Reducing the size of traditional flow battery cells will shorten the distance between the positive and negative electrode flow paths, reduce the sealing area, and make the seal more likely to fail.

[0046] According to Table 1 and Table 2, the small liquid flow battery cell of this embodiment can reflect the difference between material properties like the traditional liquid flow battery cell while using less material. The small liquid flow battery cell of this embodiment is smaller in size, easier to assemble, and less prone to leakage.

[0047] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A small-scale liquid flow battery single cell assembly, characterized in that: With the ion exchange membrane (1) as the center, a first sealing gasket frame (2), an electrode frame (3), a second sealing gasket frame (4), a bipolar plate (5), an inlet and outlet plate (7) and an end plate (8) are laminated and fixedly arranged on the left and right sides of the ion exchange membrane (1) from the inside to the outside, respectively, and an electrode (9) is embedded in the first sealing gasket frame (2), the electrode frame (3) and the second sealing gasket frame (4); the side of the inlet and outlet plate (7) facing the ion exchange membrane (1) is recessed inwardly and embedded with a current collecting plate (6); A side of the electrode frame (3) facing away from the ion exchange membrane (1) is provided with an electrolyte drainage area recessed inward from its surface, the electrolyte drainage area comprising a first electrolyte drainage area provided at the bottom of the electrode frame (3) and a second electrolyte drainage area provided at the top of the electrode frame (3). The lower part of the small-sized liquid flow battery single cell assembly is provided with a positive electrode electrolyte inlet flow channel (111) and a negative electrode electrolyte inlet flow channel (113) extending in the left-right direction, and the upper part of the small-sized liquid flow battery single cell assembly is provided with a positive electrode electrolyte outlet flow channel (112) and a negative electrode electrolyte outlet flow channel (114) extending in the left-right direction. The left end of the positive electrode electrolyte inlet channel (111) is connected to the outside, and the right end is connected to the first electrolyte drainage area of ​​the electrode frame (3) located on the left side of the ion exchange membrane (1). The right end of the negative electrode electrolyte inlet channel (113) is connected to the outside, and the left end is connected to the first electrolyte drainage area of ​​the electrode frame (3) located on the right side of the ion exchange membrane (1). The left end of the positive electrode electrolyte outlet flow channel (112) is connected to the outside, and the right end is connected to the second electrolyte drainage area of ​​the electrode frame (3) located on the left side of the ion exchange membrane (1). The right end of the negative electrode electrolyte outlet flow channel (114) is in communication with the outside, and the left end is in communication with the second electrolyte drainage area of ​​the electrode frame (3) located on the right side of the ion exchange membrane (1).

2. The small-scale liquid flow battery single cell assembly according to claim 1, characterized in that: The sum of the thicknesses of the first sealing gasket frame (2), the electrode frame (3) and the second sealing gasket frame (4) is 1 to 1.2 times the thickness of the electrode (9).

3. The small-sized liquid flow battery single cell assembly according to claim 1, characterized in that: The first sealing gasket frame (2), the electrode frame (3) and the second sealing gasket frame (4) are respectively a roundabout structure having a cavity, and the cavities of the first sealing gasket frame (2), the electrode frame (3) and the second sealing gasket frame (4) together constitute a housing cavity for the electrode (9).

4. The small-scale liquid flow battery single cell assembly according to claim 1, characterized in that: The end plate (8), the liquid inlet and outlet plate (7), the bipolar plate (5), and the lower frame of the second sealing gasket frame (4) are respectively provided with a liquid inlet through hole (121), and the upper frame of the end plate (8), the liquid inlet and outlet plate (7), the bipolar plate (5), and the second sealing gasket frame (4) are respectively provided with a liquid outlet through hole (122). The end plate (8), the inlet and outlet plate (7), the bipolar plate (5), and the inlet through hole (121) of the second sealing gasket frame (4) located on the left side of the ion exchange membrane (1) are connected to form the positive electrode electrolyte inlet flow channel (111); the end plate (8), the inlet and outlet plate (7), the bipolar plate (5), and the inlet through hole (121) of the second sealing gasket frame (4) located on the right side of the ion exchange membrane (1) are connected to form the negative electrode electrolyte inlet flow channel (113). The end plate (8) located on the left side of the ion exchange membrane (1), the liquid inlet and outlet plate (7), and the liquid outlet through hole (122) of the second sealing gasket frame (4) are connected to form the positive electrode electrolyte outlet flow channel (112), and the end plate (8) located on the right side of the ion exchange membrane (1), the liquid inlet and outlet plate (7), and the liquid outlet through hole (122) of the second sealing gasket frame (4) are connected to form the negative electrode electrolyte outlet flow channel (114).

5. The small-scale liquid flow battery single cell assembly according to claim 4, characterized in that: The liquid inlet through hole (121) of the end plate (8) and the liquid inlet through hole (121) of the liquid inlet and outlet plate (7) are connected with a pagoda joint (10), and the liquid outlet through hole (122) of the end plate (8) and the liquid outlet through hole (122) of the liquid inlet and outlet plate (7) are connected with a pagoda joint (10).

6. The small-scale liquid flow battery single cell assembly according to claim 3, characterized in that: The electrolyte drainage area comprises a guide flow channel (31) and a distribution flow channel (32); the guide flow channel (31) extends along the symmetry axis direction of the cavity of the electrode frame (3); and the width of the distribution flow channel (32) gradually decreases from the inner frame of the electrode frame (3) to the guide flow channel (31).

7. The small-scale liquid flow battery single cell assembly according to claim 1, characterized in that: Positioning through holes (13) for positioning and installing screws are respectively provided at the four corners of the ion exchange membrane (1), the first sealing gasket frame (2), the electrode frame (3), the second sealing gasket frame (4), the bipolar plate (5), the inlet and outlet plates (7) and the end plate (8). The small-sized liquid flow battery single cell assembly also includes screws for laminating and fixing the ion exchange membrane (1), the first sealing gasket frame (2), the electrode frame (3), the second sealing gasket frame (4), the bipolar plate (5), the inlet and outlet plates (7) and the end plate (8).

8. The small-scale liquid flow battery single cell assembly according to claim 4, characterized in that: A sealing ring is provided between the liquid inlet through hole (121) of the liquid inlet and outlet plate (7) and the liquid inlet through hole (121) of the bipolar plate (5), and / or a sealing ring is provided between the liquid outlet through hole (122) of the liquid inlet and outlet plate (7) and the liquid outlet through hole (122) of the bipolar plate (5).

9. The small-scale liquid flow battery single cell assembly according to claim 1, characterized in that: The electrode frame (3) is made of PP, PE or PVC; and / or the liquid inlet and outlet plate (7) is made of PP, PE or PVC; and / or the end plate (8) is made of aluminum alloy, stainless steel or carbon steel; and / or the first sealing gasket and the second sealing gasket are independently made of rubber or silicone; and / or the length and width of the ion exchange membrane (1), the first sealing gasket frame (2), the electrode frame (3), the second sealing gasket frame (4), the liquid inlet and outlet plate (7) and the end plate (8) are independently 50 to 150 mm.

10. A small-scale liquid flow battery cell, characterized in that: The small-sized liquid flow battery cell comprises the small-sized liquid flow battery cell assembly according to any one of claims 1 to 8.

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