Flow battery and single battery

Abstract

The utility model relates to a flow battery and a single battery. The single cell comprises two half cells, and each half cell comprises an end plate, a bipolar plate and an electrode which are sequentially stacked in the thickness direction; at least one half cell further comprises a first screw rod arranged on the end plate, the tail end of the first screw rod penetrates through the center of the end plate and is in contact with the bipolar plate, and when the first screw rod rotates, the bipolar plate is pushed to compress the electrode in the thickness direction. The flow battery and the single battery provided by the utility model have a wider electrode compression ratio regulation and control range, and the test precision and efficiency are improved.

Description

Technical Field

[0001] The utility model relates to the field of batteries, in particular to a liquid flow battery and a single battery. Background Art

[0002] As the contradiction between modern economic and social development and the insufficient supply of traditional energy becomes increasingly prominent, people are forced to seek new energy sources such as wind and solar energy to meet the needs of production and life. As energy demand grows, new energy sources such as wind and solar energy account for an increasing proportion of the energy supply. However, the instability of wind energy and the intermittent nature of solar energy have brought difficulties to energy utilization, making large-scale energy storage research imperative.

[0003] Flow batteries are currently attracting widespread attention due to their high safety, large capacity, long lifespan, and flexible power and capacity adjustment. Electrodes are key components of flow batteries. The electrode compression ratio, which refers to the degree to which the electrodes are compressed during the compression process, influences mass transfer efficiency and the battery's energy efficiency. A high compression ratio reduces mass transfer efficiency and increases pump consumption, while a low compression ratio can lead to excessive contact resistance. A suitable electrode compression ratio can effectively improve battery performance without increasing operating costs.

[0004] Therefore, it is necessary to test the three major efficiency indicators of the battery (voltage efficiency, coulombic efficiency, and energy efficiency) at different compression ratios. These efficiency indicators jointly determine the performance and practicality of the flow battery. By testing different compression ratios, we can select the electrode compression ratio that meets the operating conditions.

[0005] At present, most testing methods are to achieve a certain compression ratio of the electrode by adjusting the thickness of the sealing film, electrode frame, etc. and adjusting the pre-tightening force of the bolts. This usually requires setting multiple bolts around the end plate of the battery structure and adjusting the axial feed of the multiple bolts to achieve compression of the electrode. However, this method requires the design of single cells of different sizes for testing electrodes of different thicknesses. At the same time, in addition to the need to design single cells separately for different electrode sizes, the above method also needs to ensure that the pre-tightening force of multiple bolts is consistent, resulting in large test errors and a small control range for the electrode compression ratio. Utility Model Content

[0006] In view of the above-mentioned problems in the prior art, the present invention proposes a liquid flow battery and a single cell, which can easily adjust the electrode compression ratio and improve the test efficiency.

[0007] Specifically, the utility model proposes a single cell for a liquid flow battery, comprising two half-cells, each half-cell comprising an end plate, a bipolar plate and an electrode stacked in sequence along the thickness direction;

[0008] At least one half-cell further includes a first screw disposed on the end plate, wherein the tail end of the first screw passes through the center of the end plate and contacts the bipolar plate. When the first screw rotates, it pushes against the bipolar plate and compresses the electrode along the thickness direction.

[0009] According to one embodiment of the present invention, at least one half-cell further includes a scale component, which is arranged on the end plate, and a threaded hole is opened in the center of the end plate. The first screw passes through the scale component and is fixed with the threaded hole by threading. The surface of the scale component is provided with a plurality of scale lines surrounding the first screw, and the scale lines are used to indicate the rotation angle of the first screw.

[0010] According to one embodiment of the present invention, at least one half-cell further includes a connecting gasket, a second screw and a nut, and the tail end of the second screw passes through the bipolar plate, the end plate and the connecting gasket in sequence, and is fixed with the nut.

[0011] According to one embodiment of the present invention, the bipolar plate includes a first plate body and a second plate body. A mounting groove is provided on the surface of the first plate body. The second plate body cooperates with the mounting groove structure and is suitable for being installed in the mounting groove.

[0012] According to an embodiment of the present invention, the bipolar plate further includes a sealing line, and a line groove is formed around the outer edge of the second plate body, and the sealing line is arranged in the line groove.

[0013] According to an embodiment of the present invention, the diameter of the sealing line is 1 to 3 mm, and the compression rate ranges from 10% to 20%.

[0014] According to one embodiment of the present invention, the outer edge of the second plate has a plurality of protrusions.

[0015] According to one embodiment of the present invention, the second plate body has a through hole for the second screw to pass through and a groove located around the through hole. The bipolar plate also includes an anti-corrosion sealant arranged at the fitting position between the head of the second screw and the groove.

[0016] According to one embodiment of the present invention, each half-cell further includes a first sealing film, an electrode frame, and a second sealing film that are stacked from the electrode toward the center of the single cell.

[0017] The present invention also provides a flow battery, including the aforementioned single cell. The flow battery and single cell provided by the present invention can directly compress the electrode by rotating the first screw, providing a wider range of electrode compression ratio control, thereby improving test accuracy and efficiency.

[0018] It should be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are included to provide further explanation of the present invention, and are incorporated into and constitute a part of this application. The accompanying drawings illustrate embodiments of the present invention and, together with this specification, serve to explain the principles of the present invention. In the accompanying drawings:

[0020] Figure 1 A schematic three-dimensional structure diagram of a single battery in an assembled state according to an embodiment of the present invention is shown.

[0021] Figure 2 A cross-sectional view showing an assembled state of a single battery according to an embodiment of the present invention is shown.

[0022] Figure 3 An exploded view of a single cell according to an embodiment of the present invention is shown.

[0023] Figure 4 yes Figure 3 Schematic diagram of the structure of the first plate body of the bipolar plate.

[0024] Figure 5 yes Figure 3 Schematic diagram of the structure of the second plate body of the bipolar plate. DETAILED DESCRIPTION

[0025] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0026] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0028] Unless otherwise specified, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. Technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, and therefore, once an item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0029] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0030] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0031] Figure 1 A schematic three-dimensional structure diagram of a single battery in an assembled state according to an embodiment of the present invention is shown. Figure 3 A cross-sectional view showing an assembled state of a single battery according to an embodiment of the present invention is shown. Figure 2An exploded view of a single cell according to one embodiment of the present invention is shown. As shown, the single cell 100 for a liquid flow battery in this embodiment includes end plates 101 on both sides and a battery assembly unit 103 disposed between the two end plates 101. A bipolar plate 102 is disposed between each end plate 101 and the battery assembly unit 103. In this embodiment, the battery assembly unit 103 is designed symmetrically along the thickness of the single cell. Specifically, the battery assembly unit 103 includes a diaphragm 131, with a first sealing film 132, an electrode frame 133, a second sealing film 134, and an electrode 135 stacked sequentially from the inside out on both sides, centered around the diaphragm 131. However, it is understood that the battery assembly unit 103 may not be symmetrical if necessary or permitted. From one perspective, the single cell 100 is formed by butting together two half-cells, each of which includes at least an end plate 101, a bipolar plate 102, and an electrode 135 stacked sequentially along the thickness direction.

[0032] In some examples, the active area of ​​electrode 135 is 84*60cm 2 The single cell 100 is designed based on the reference. By way of example and not limitation, the electrode 135 is a 2.5 mm thick carbon felt electrode. By way of example and not limitation, the first sealing film 132 and the second sealing film 134 are both 0.3 mm thick.

[0033] In some examples, a plurality of threaded holes 101 a are respectively defined on the edges of the two end plates 101 for fastening with bolts (not shown).

[0034] Continue to refer Figure 1 Each half-cell further includes a first screw 104. The first screw 104 is mounted on the end plate 101. The tail end of the first screw 104 extends through the center of the end plate 101 and contacts the bipolar plate 102. When the first screw 104 rotates, it pushes against the bipolar plate 102 and compresses the electrode 135 along its thickness to achieve the electrode compression ratio required for testing. In other embodiments, only one half-cell may include the first screw 104. The other half-cell may use other known components to compress the electrode, or may not include components for compressing the electrode, as desired.

[0035] It should be noted that the single cell 100 provided by the present invention is suitable for all-vanadium liquid flow batteries and can also be expanded to any compressible electrode liquid flow battery, without being limited by the size of the single cell and the type of compressible electrode. The existing technology requires adjusting the thickness of the sealing film, electrode frame, etc. by adjusting the axial feed rate of multiple bolts to achieve compression of the electrode. Compared with the existing technology, the single cell 100 provided by the present invention can directly compress the electrode 135 through the bipolar plate 102 by rotating the first screw 104, without adjusting the thickness of the sealing film 132 and 134, electrode frame 133 and other components; and the electrode 135 is compressed through the entire surface of the bipolar plate 102, without considering the synchronous feed rate of multiple bolts, and effectively adjusting the compression ratio of the electrode 135 in the battery assembly unit 103. Because the electrode 135 is directly compressed by the bipolar plate 102, it has a wider compression ratio control range, thereby improving test efficiency.

[0036] In some embodiments of the present application, assuming that the initial thickness of the electrode 135 is d1, the thickness of the electrode 135 after compression is d2, and the rotation angle of the first screw 104 is θ, then the corresponding relationship between the rotation angle θ and the compression ratio α of the electrode 135 is:

[0037] In some embodiments of the present application, one or both half-cells further include a scale component 105, which is disposed on the end plate 101. A threaded hole 101b is provided in the center of the end plate 101, and the first screw 104 passes through the scale component 105 and is threadedly engaged with the threaded hole 101b. A plurality of scale lines 105a surrounding the first screw 104 are provided on the surface of the scale component 105, and the scale lines are used to indicate the rotation angle of the first screw 104. In other words, by observing the rotation angle of the first screw 104, its movement distance in the thickness direction of the half-cell can be known. By way of example and not limitation, the scale component 105 is fixed to the end plate 101 by gluing.

[0038] In some embodiments of the present application, the rotation angle of the first screw 104 passing through adjacent scale lines is 30°. If the pitch of the first screw 104 is 2mm, the movement distance of the first screw 104 when rotating 30° is 2mm / 12. Designing this structure is conducive to controlling the movement amount of the first screw 104 and improving the compression accuracy. When the two half-cell structures are exactly the same, it is easy to keep the compression amount of the electrodes 135 at both ends equal, further improving the test accuracy. In some embodiments of the present application, the first screw 104 uses M8~M20 bolts, such as M18 screws. Figure 4 yes Figure 3 Schematic diagram of the structure of the first plate body of the bipolar plate. Figure 5 yes Figure 3 Schematic diagram of the structure of the second plate body of the bipolar plate. Figure 2 and Figure 3 As shown, the bipolar plate 102 includes a first plate body 121 and a second plate body 122. A mounting groove 121a is provided on the surface of the first plate body 121, and the second plate body 122 matches the shape of the mounting groove 121a and is suitable for being installed in the mounting groove 121a.

[0039] In some embodiments of the present application, the bipolar plate 102 further includes a sealing line 123. A sealing groove 122a is formed around the outer edge of the second plate 122, and the sealing line 123 is disposed within the groove 122a. The sealing line 123 seals the bipolar plate 102 using a wire seal. In some embodiments, the sealing line 123 is O-shaped and has a diameter of 1 mm. After assembly, the compression rate of the sealing line 123 is approximately 15%.

[0040] Rotating the first screw 104 is used to push the second plate 122 along the depth direction of the mounting groove 121a of the first plate 121, gradually widening the gap between the two. The second plate 122 is moved along the thickness direction of the single cell 100 to compress the electrode 135 in the battery assembly unit 103. The theoretical maximum compression ratio depends on the maximum compression ratio of the electrode 135 material itself and the theoretical maximum compression ratio of the structural design. Assuming that the recessed depth of the first plate 121 is h1, the thickness of the second plate 122 retained in the mounting groove 121a is h2, and the initial thickness of the electrode 135 is d, the theoretical maximum compression ratio of the structure is The recess depth refers to the depth of the mounting groove 121a of the first plate 121. This calculation is based on the assumption that the second plate 122 can only reach the outermost portion of the first plate 121. Theoretically, the second plate 122 can only move within the mounting groove 121a of the first plate 121 and cannot escape from the mounting groove 121a.

[0041] In some embodiments of the present application, the diameter of the sealing line 123 is 1 to 3 mm, and the compression rate is in the range of 10% to 20%. More preferably, the sealing line 123 is made of rubber, preferably fluororubber.

[0042] Furthermore, liquid inlet and outlet ports 121b and 121c are provided on the first plate 121. To prevent liquid leakage, the liquid inlet and outlet ports 121b and 121c are offset outward based on the slot of the mounting slot 121a.

[0043] Preferably, if Figure 5As shown, the edge of the second plate 122 is formed with multiple outward protrusions 122b. These protrusions 122b align with the shape of the mounting groove 121a of the first plate 121. When the second plate 122 moves along the depth of the mounting groove 121a of the first plate 121, the multiple protrusions 122b serve as guides, ensuring smooth movement of the second plate 122 along the thickness of the half-cell. The second plate 122 and the electrode 135 are integrally bonded, minimizing the uneven compression that may occur when the electrode 135 is compressed.

[0044] Back to Figure 3 As shown, in some embodiments of the present application, the half-cell further includes a connecting washer 106, a second screw 107, and a nut 108. The tail end of the second screw 107 passes through the through-hole 106a provided in the second plate 122, the first plate 121, the end plate 101, and the connecting washer 106, sequentially from the inside out, and is secured with the nut 108. In other words, the connecting washer 106 is disposed on the second screw 107 and located between the nut 106 and the end plate 101. When the electrode 135 in the battery assembly unit 103 is compressed, the first screw 104 can be rotated in the opposite direction to reset it. The connecting washer 106 is then pulled toward the outside of the electrode 135. The connecting washer 106 drives the second screw 107 outward via the nut 108. The head of the second screw 107 is larger than the mating through-hole in the second plate 122, thereby returning the second plate 122 to its original position before compression, and the electrode 135 gradually returns to its initial uncompressed state.

[0045] In some embodiments of the present application, the second screw 115 is made of an anti-corrosion material to resist corrosion from liquid in the battery.

[0046] In some embodiments of the present application, the end plate 101 has two through holes 101 c on both sides of the threaded hole 101 b to cooperate with the movement of the second screw rod 107 .

[0047] In some embodiments of the present application, the second plate 122 has a through-hole 122c for the second screw 107 to pass through and a groove 122d located around the through-hole. The bipolar plate 102 also includes an anti-corrosion sealant disposed at the junction between the head of the second screw 115 and the groove 122d of the second plate 122. The anti-corrosion sealant is used to provide a seal and fixation between the second screw 115 and the second plate 122. After assembly is completed, the second screw 107 no longer rotates and is primarily used to cooperate with the connecting gasket 106 to provide a reset function for the electrode 135 to facilitate subsequent testing.

[0048] In some embodiments, the half-cell further includes a third sealing film 109 disposed between the bipolar plate 102 and the end plate 101 to achieve a fastening effect therebetween.

[0049] The present invention also provides a liquid flow battery, comprising the aforementioned single cell 100 .

[0050] The compression process of the aforementioned single cell is described below. The tail ends of the two first screws 104 are in close contact with the outer side of the second plate 122 of each bipolar plate 102. The two first screws 104 are rotated separately or simultaneously to push the second plate 122 in the thickness direction of the single cell 100, thereby compressing the electrode 135. After the electrode 135 is compressed, the first screws 104 are reset. The connecting gaskets 105 on both sides of the end plate 101 are pulled back, and the second screws 107 cooperate to restore the compression ratio of the electrode 135.

[0051] In some embodiments, by calculating the dimensions of various related components, it is found that the single cell 100 of the embodiment of the present application can provide a carbon felt electrode with a thickness of 2.5 mm, and the compression range is 0% to 36%.

[0052] In one example, reference Figures 1 to 3 , after the single battery 100 is assembled, it is symmetrically arranged along its thickness direction. Measure the distance h from the top surface of the first screw 104 to the surface of the end plate 101. The distance h corresponds to the state of the first screw 104 when the electrode 135 is in an uncompressed state, which is used to restore the electrode 135 to an uncompressed state later. Perform a cyclic inspection sealing test, run for 10 minutes without leakage and the sealing meets the requirements, and then perform a performance test after adjusting the compression ratio. In this example, the electrodes 135 on both sides are compressed symmetrically, and the first screws 104 on both sides are rotated 1 / 12 of a circle, corresponding to a compression ratio of 6.67% for the electrodes 135 of the battery combination unit 103. After the electrode 135 is reset, the first screw 104 is rotated 5 / 12 of a circle, corresponding to a compression ratio of 16.67% for the electrodes 135 of the battery combination unit 103. The results are shown in Table 1.

[0053] Table 1

[0054]

[0055] It will be apparent to those skilled in the art that various modifications and variations can be made to the exemplary embodiments described above without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention cover modifications and variations of the present invention that fall within the scope of the appended claims and their equivalents.

Claims

1. A single cell, suitable for a liquid flow battery, comprising two half cells, characterized in that: Each half-cell comprises an end plate, a bipolar plate and an electrode stacked in sequence along the thickness direction; At least one half-cell further includes a first screw disposed on the end plate, wherein the tail end of the first screw passes through the center of the end plate and contacts the bipolar plate. When the first screw rotates, it pushes against the bipolar plate and compresses the electrode along the thickness direction.

2. The single cell according to claim 1, wherein: At least one half-cell further comprises a scale component, which is arranged on the end plate, and a threaded hole is opened in the center of the end plate. The first screw passes through the scale component and is threadedly fixed to the threaded hole. The surface of the scale component is provided with a plurality of scale lines surrounding the first screw, and the scale lines are used to indicate the rotation angle of the first screw.

3. The single cell according to claim 1 or 2, wherein: At least one half-cell further includes a connecting gasket, a second screw and a nut, wherein the tail end of the second screw passes through the bipolar plate, the end plate and the connecting gasket in sequence and is fixed with the nut.

4. The single cell according to claim 3, wherein: The bipolar plate includes a first plate body and a second plate body. A mounting groove is provided on the surface of the first plate body. The second plate body cooperates with the mounting groove structure and is suitable for being installed in the mounting groove.

5. The single cell according to claim 4, wherein: The bipolar plate further includes a sealing line. A line groove is formed around the outer edge of the second plate body, and the sealing line is arranged in the line groove.

6. The single cell according to claim 5, wherein: The diameter of the sealing line is 1-3 mm, and the compression rate ranges from 10% to 20%.

7. The single cell according to claim 4, wherein: The outer edge of the second plate body has a plurality of protrusions.

8. The single cell according to claim 4, wherein: The second plate body has a through hole for the second screw to pass through and a groove located around the through hole. The bipolar plate also includes an anti-corrosion sealant provided at the matching position between the head of the second screw and the groove.

9. The single cell according to claim 1, wherein: Each half-cell further includes a first sealing film, an electrode frame, and a second sealing film that are stacked from the electrodes toward the center of the single cell.

10. A flow battery, characterized in that: The invention comprises a single cell according to any one of claims 1 to 9.

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