Bipolar plate of flow battery and flow battery

Abstract

The utility model discloses a bipolar plate of a flow battery and the flow battery, and belongs to the technical field of new energy. The flow battery bipolar plate mainly comprises a plate body, flow channels are formed in an electrode area, in contact with electrodes, of the plate body, the electrode area is provided with an electrolyte inlet side and an electrolyte outlet side, the flow channels comprise a plurality of first flow guide channels and a plurality of second flow guide channels, and the first flow guide channels extend in the direction from the electrolyte inlet side to the electrolyte outlet side. The second flow guide channels are of a wave-shaped structure and extend in the direction intersecting with the first flow guide channel, and the multiple second flow guide channels are arranged at intervals in the length direction of the first flow guide channel. And the end part of each flow guide channel I is connected and communicated with the corner of the adjacent flow guide channel II to form a polygonal flow guide structure which is concave inwards in the direction from the inlet side of the electrolyte to the outlet side. According to the bipolar plate of the flow battery, the flow distribution uniformity of electrolyte can be improved, a flow dead zone is reduced, and the pressure drop is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy, in particular to a liquid flow battery bipolar plate and a liquid flow battery. Background Art

[0002] Liquid flow batteries are mainly composed of an electrochemical reaction stack (composed of multiple single cells connected in series) and tanks for storing positive and negative electrolytes. Driven by a pump, the positive and negative electrolytes circulate through the positive and negative electrodes of each single cell respectively and undergo electrochemical reactions to realize the charging or discharging of the liquid flow battery. The mass transfer process of a liquid flow battery refers to the process in which the electrolyte enters the single cell from the tank, flows through the flow channel and penetrates into the pores of the porous electrode, and finally the reactive ions in the electrolyte migrate from the electrolyte to the electrode surface for electrochemical reaction. Whether the reactive ions can reach the reaction surface in time will directly affect the concentration overpotential of the battery and thus affect the voltage efficiency of the battery. At the same time, the mass transfer process will consume pump power, and the size of the pump power will affect the system energy efficiency of the liquid flow battery. Different flow channel designs of the liquid flow battery will have different effects on the mass transfer process of the electrolyte. Therefore, the optimization of the bipolar plate flow channel structure is of great significance to the performance of the liquid flow battery.

[0003] Serpentine flow channels and interdigitated flow channels are the two most commonly used flow channels in vanadium batteries. For large vanadium battery stacks, the length of the serpentine flow channel is significantly greater than that of other flow channels. Therefore, the pressure drop of the serpentine flow channel is the largest, and the pump power loss is the largest. At the same time, its non-forced convection characteristics result in poor convective mass transfer of active materials and low voltage efficiency when the electrode porosity is low and the compression ratio is relatively large. For the interdigitated flow channel, the electrolyte flows from one side of the main channel and enters the branch channel in turn. This liquid distribution method cannot evenly distribute the electrolyte to each branch channel. The uniformity of the electrolyte distribution deteriorates, which is bound to lead to a large concentration overpotential.

[0004] Therefore, it is necessary to provide a new bipolar plate for flow batteries to improve the uniformity of electrolyte velocity distribution and reduce pressure drop. Utility Model Content

[0005] In view of the above-mentioned problems existing in the prior art, the purpose of the embodiments of the present invention is to provide a liquid flow battery bipolar plate and a liquid flow battery, which can improve the flow distribution uniformity of the electrolyte and reduce the pressure drop.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a liquid flow battery bipolar plate, including a plate body, an electrode area on the plate body that contacts the electrode is provided with a flow channel, the electrode area has an inlet side and an outlet side for the electrolyte, the flow channel includes a plurality of guide channels 1 and a plurality of guide channels 2, the guide channel 1 extends in a direction from the inlet side of the electrolyte to the outlet side, the guide channel 2 has a wavy structure and is extended in a direction intersecting the guide channel 1, and the plurality of guide channels 2 are arranged at intervals along the length direction of the guide channel 1, and the ends of the guide channel 1 are respectively connected to the corners of adjacent guide channels 2 to form a polygonal guide structure that is concave in the direction from the inlet side of the electrolyte to the outlet side.

[0007] Furthermore, the guide channel 1 is provided in a plurality of rows; the plurality of rows of guide channels 1 are arranged at equal intervals, and the plurality of guide channels 1 in each row of guide channels 1 are arranged at equal intervals;

[0008] The guide channels 2 are provided in multiple rows, the corners of the wave-shaped structure of the guide channels 2 are of the same size, the two adjacent rows of guide channels 2 are symmetrically arranged, and the guide channels 1 and 2 are spaced apart.

[0009] Furthermore, the end of the first flow guide channel is connected to the corner of the adjacent second flow guide channel to form a pentagonal and / or hexagonal flow guide structure that is concave in the direction from the inlet side to the outlet side of the electrolyte.

[0010] Furthermore, the angle range of the corner of the wavy structure of the second flow guide channel is 90° to 180°.

[0011] Furthermore, on the plane of the bipolar plate electrode region, the area occupied by the flow channel is 10% to 90% of the area of ​​the electrode region.

[0012] Furthermore, the width of the flow channel is 1 mm to 50 mm.

[0013] Furthermore, the depth of the flow channel is 1 mm to 50 mm.

[0014] Furthermore, the width of the plate body around the electrode area of ​​the bipolar plate is 10mm to 500mm.

[0015] Furthermore, the bipolar plate has a thickness of 1 mm to 100 mm.

[0016] Furthermore, the internal corners of the flow channel are all arc-shaped transitions.

[0017] Furthermore, the end of the flow channel close to the electrolyte outlet side is closed, and the flow channel is connected to the electrolyte inlet side.

[0018] On the other hand, the present invention also provides a liquid flow battery, comprising the aforementioned liquid flow battery bipolar plate.

[0019] The beneficial effect of the present invention is that the liquid flow battery bipolar plate provided by the present invention forms a polygonal guide structure that is concave in the direction from the inlet side to the outlet side of the electrolyte through the guide channel one and multiple guide channels two. Since the structure is concave in the direction from the inlet side to the outlet side of the electrolyte, when the electrolyte flows from the inlet side of the electrode area to the outlet side of the electrode area, multiple forward-to-both-sides and backward-backward paths are formed that cover the electrode area. This path ensures that the electrolyte on the electrode area is repeatedly and regularly dispersed and gathered during the flow process, strengthens the flow mass transfer of the electrolyte, improves the flow distribution uniformity of the electrolyte, and ensures the residence time of the electrolyte in the electrode area, reducing the dead zone of the flow channel. At the same time, since the total length of the flow channel is relatively small, it can also reduce the pressure drop and reduce the pump power loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 A schematic diagram of the three-dimensional structure of a bipolar plate for a flow battery provided in an embodiment of the present utility model.

[0022] Figure 2 for Figure 1 A magnified schematic diagram of area A in the middle.

[0023] Figure 3 A velocity distribution diagram generated by modeling the bipolar plate of the flow battery provided by an embodiment of the present invention using a low Reynolds number ke model.

[0024] Figure 4 A pressure distribution diagram generated by modeling the bipolar plate of the flow battery provided by an embodiment of the present invention using a low Reynolds number ke model.

[0025] Among them, the reference numerals in the figure are: 100, bipolar plate; 101, inlet side; 102, outlet side; 200, flow channel; 21, flow guide channel 1; 22, flow guide channel 2; 23, intersection area 1; 24, intersection area 2. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] It should be noted that when an element is referred to as being “connected to” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0028] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0029] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship 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 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 present invention.

[0030] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, when the phrases "in one embodiment," "in some embodiments," or "in some embodiments" appear in various places throughout this specification, not all references are to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0031] Example 1

[0032] Please refer to Figures 1 to 4 As shown, the bipolar plate for a flow battery provided by the present invention is now described. The bipolar plate 100 is a flat plate with an area for contact with electrodes, referred to as the electrode region, located in the middle of one or both of its surfaces. The electrolyte flows into the electrode region from one side and out of the electrode region through the opposite side. The inflow side is referred to as the electrolyte inlet side 101, and the outflow side is referred to as the electrolyte outlet side 102.

[0033] And in Figure 2The dotted arrows in the figure show the simplified direction of the electrolyte in the flow channel 200. The flow battery bipolar plate includes a plate body 100. The flow channel 200 is opened in the electrode area in contact with the electrode on the plate body 100. The inlet side 101 and the outlet side 102 of the electrolyte are arranged from bottom to top on the electrode area. The flow channel 200 includes a plurality of guide channels 1 21 and a plurality of guide channels 2 22. The plurality of guide channels 1 21 extend in the direction from the inlet side 101 of the electrolyte to the outlet side 102. The guide channel 2 22 has a wavy structure and extends in the direction intersecting the guide channel 1 21. The plurality of guide channels 22 are arranged at intervals along the length direction of the guide channel 1 21. The ends of the guide channel 1 21 are respectively connected to the corners 23 of the adjacent guide channels 22 to form a polygonal guide structure that is concave in the direction from the inlet side 101 of the electrolyte to the outlet side 102. The flow guide channel 1 21 and the flow guide channel 2 22 form an intersection area at the connection point. The intersection area is located at the end of the flow guide channel 1 21 close to the outlet side 102 to form an intersection area 1 23. In this way, when the electrolyte flows from the inlet side 101 to the outlet side 102 from the flow guide channel 1 21 and enters the intersection area 1 23, the electrolyte in the intersection area 1 23 is forced to disperse along the flow guide channel 2 22 back to the intersection area 1 23. The intersection area is located at the end of the flow guide channel 1 21 close to the inlet side 101. When the electrolyte dispersed from the intersection area 1 23 along the guide channel 2 22 on both sides of the intersection area 24 converges to the intersection area 24, the electrolyte in the intersection area 24 will be forced to converge and flow to the nearest guide channel 1 21, and continue to flow along the guide channel 1 21 from the inlet side 101 to the outlet side 102. Through the above technical solution, the intersection area 1 23 and the intersection area 24 are alternately arranged in the horizontal direction. , and the intersection area 1 23 and the intersection area 2 24 are distributed in an array in the vertical direction. In this way, when the electrolyte is input from the inlet side 101 and output from the outlet side 102, the electrolyte in the guide channel 1 21 below the intersection area 1 23 will be dispersed to both sides along the guide channel 2 22 in the intersection area 1 23, and the electrolyte in the guide channel 2 22 on both sides of the intersection area 2 24 will gather upward from the intersection area 2 24 to the guide channel 1 21, forming a plurality of forward-to-both-side and backward-backward paths covering the electrode area. This path ensures that the electrolyte on the electrode area is repeatedly and regularly dispersed and gathered during the flow process, strengthens the flow mass transfer of the electrolyte, improves the flow distribution uniformity of the electrolyte, and ensures the residence time of the electrolyte in the electrode area, reducing the dead zone of the flow channel; at the same time, due to the small total length of the flow channel, it can also reduce the pressure drop and reduce the pump power loss.

[0034] like Figure 1As shown, in some embodiments, multiple rows of guide channels 21 are provided; multiple guide channels 21 in each row of guide channels 1 21 are arranged at equal intervals; multiple rows of guide channels 2 22 are provided, the corners of the wavy structure of guide channels 2 22 are consistent in size, the two adjacent rows of guide channels 2 22 are symmetrically arranged, and the guide channels 1 21 and the guide channels 2 22 are spaced apart.

[0035] like Figure 1 As shown, in some embodiments, the end of the guide channel 1 21 is connected to the corner of the adjacent guide channel 2 22 to form a pentagonal and / or hexagonal guide structure that is concave in the direction from the inlet side 101 to the outlet side 102 of the electrolyte.

[0036] like Figure 2 As shown, in some embodiments, the angle of the corner of the wavy structure of the second flow guide channel 22 ranges from 90° to 180°.

[0037] In some embodiments, on the plane of the plate 100 corresponding to the electrode region, the area occupied by the flow channel 200 is 10% to 90% of the area of ​​the electrode region.

[0038] In some embodiments, the width of the flow channel 200 is 1 mm to 50 mm, and the depth of the flow channel 200 is 1 mm to 50 mm.

[0039] In some embodiments, the width of the plate body around the electrode region on the plate body 100 is 10 mm to 500 mm; the thickness of the plate body 100 is 1 mm to 100 mm.

[0040] In some embodiments, the internal corners of the flow channel 200 are all arc-shaped transitions.

[0041] In some embodiments, the material of the plate 100 may be, but is not limited to, graphite and other materials.

[0042] In some embodiments, the flow channel 200 on the plate body can be formed by, but not limited to, machining, engraving, hot pressing and other processing techniques.

[0043] like Figure 1 and Figure 2As shown, in some embodiments, the end of the flow channel 200 near the electrolyte outlet side 102 is closed, and the flow channel 200 is connected to the electrolyte inlet side 100. The end of the flow channel 101 closest to the inlet side 101 is open, so that the electrolyte on the inlet side 101 can smoothly flow from the flow channel 101 closest to the inlet side 101 into the flow channel 200. The end of the flow channel 101 closest to the outlet side 102 is closed. Since the end of the flow channel 101 near the outlet side 102 is closed, the electrolyte flowing in the flow channel 101 is obstructed, thereby reducing the flow rate, thereby allowing more electrolyte on the outlet side 102 to flow into the electrode for electrochemical reaction.

[0044] Due to the bipolar plates of the flow battery provided by the embodiment of the present invention, the electrolyte is evenly distributed during the flow process, the pressure drop is reduced, and the system pressure loss and pump work loss can be reduced.

[0045] The flow battery bipolar plate provided in the embodiment of the present invention is suitable for use in flow batteries of various sizes, and the width and depth of the flow channel 200 can be flexibly adjusted to enhance the mass transfer process and improve the efficiency of the battery system.

[0046] Example 2

[0047] See Figure 1 The structure is the same as that of Example 1. Specifically, the flow battery bipolar plate is pressed from graphite, with a plate thickness of 5mm. The electrode area is rectangular, with the electrolyte inlet side 101 and outlet side 102 having a side length of 1100mm; the left and right side lengths are 340mm; the depth of guide channel 1 21 and guide channel 2 22 is 2mm, the width is 5mm, the length of the bottom guide channel 1 21 is 50mm, the length of the middle guide channel 1 21 is 100mm, and the length of the top guide channel 1 is 45mm. The spacing between each row of guide channels 1 21 is 110mm, the corner of guide channel 2 22 is 120°, and the length of each folded edge of guide channel 2 22 is 63.5mm. All intersections with corners are transitioned into arcs. The grooves on the bipolar plate are formed by machining.

[0048] The bipolar plate with the above data was modeled using the low Reynolds number ke model. Figure 3 and Figure 4The flow rate and pressure distribution results shown show uniform flow across the electrode area of ​​the electrode plate 100, with no electrolyte failure due to excessive flow. This improves electrolyte flow and mass transfer in the center of the bipolar plate, reduces dead zone area, and minimizes mass transfer overpotential due to concentration polarization. Furthermore, the pressure distribution diagram shows minimal pressure variation and reduced pressure drop, thereby reducing pump power losses. Furthermore, the flow rate is significantly reduced near the flow guide 21 closest to the outlet 102, helping to ensure that more electrolyte from the outlet 102 flows into the electrodes for electrochemical reaction.

[0049] Example 3

[0050] The utility model also provides a liquid flow battery, comprising the aforementioned liquid flow battery bipolar plate, which has the effects of low pump consumption and improved uniformity of electrolyte distribution.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A bipolar plate for a liquid flow battery, characterized in that: The plate comprises a plate body, wherein an electrode region of the plate body in contact with the electrode is provided with a flow channel, and the electrode region has an inlet side and an outlet side for the electrolyte; The flow channel includes multiple flow guide channels 1 and multiple flow guide channels 2. The flow guide channels 1 extend in a direction from the inlet side of the electrolyte to the outlet side. The flow guide channels 2 have a wavy structure and extend in a direction intersecting the flow guide channels 1. Multiple flow guide channels 2 are arranged at intervals along the length direction of the flow guide channels 1. The ends of the flow guide channels 1 are connected to the corners of the adjacent flow guide channels 2 to form a polygonal flow guide structure that is concave in the direction from the inlet side of the electrolyte to the outlet side.

2. The bipolar plate for a flow battery according to claim 1, wherein: The guide channels 1 are arranged in a plurality of rows; the guide channels 1 in each row are arranged at equal intervals; The guide channels 2 are provided in multiple rows, the corners of the wave-shaped structure of the guide channels 2 are of the same size, the two adjacent rows of guide channels 2 are symmetrically arranged, and the guide channels 1 and 2 are spaced apart.

3. The bipolar plate for a flow battery according to claim 1, wherein: The end of the first flow guide channel is connected to the corner of the adjacent second flow guide channel to form a pentagonal and / or hexagonal flow guide structure that is concave in the direction from the inlet side to the outlet side of the electrolyte.

4. The bipolar plate for a flow battery according to claim 1, wherein: The angle range of the corner of the wavy structure of the second flow guide channel is 90° to 180°.

5. The bipolar plate for a flow battery according to claim 1, wherein: On the plane of the electrode region of the bipolar plate, the area occupied by the flow channel is 10% to 90% of the area of ​​the electrode region.

6. The bipolar plate for a flow battery according to claim 1, wherein: The width of the flow channel is 1 mm to 50 mm; and / or the depth of the flow channel is 1 mm to 50 mm.

7. The bipolar plate for a flow battery according to claim 1, wherein: The width of the bipolar plate around the upper electrode area is 10 mm to 500 mm; and / or the thickness of the bipolar plate is 1 mm to 100 mm.

8. The bipolar plate for a flow battery according to claim 1, wherein: The internal corners of the flow channel are all arc-shaped transitions.

9. The bipolar plate for a flow battery according to claim 1, wherein: The end of the flow channel close to the electrolyte outlet side is closed, and the flow channel is communicated with the electrolyte inlet side.

10. A flow battery, characterized in that: A liquid flow battery bipolar plate comprising the liquid flow battery bipolar plate according to any one of claims 1 to 9.

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