Electrode frame, flow battery, and flow battery stack

Abstract

This invention provides an electrode frame, a flow battery, and a flow battery stack, belonging to the field of energy storage technology. The electrode frame includes a positive electrode frame and a negative electrode frame stacked together by a first insulating layer. The first end of the positive electrode frame has a first number of positive electrolyte inlet holes along its thickness direction, the second end of the positive electrode frame has a second number of positive electrolyte outlet holes along its thickness direction, the third end of the negative electrode frame has a third number of negative electrolyte inlet holes along its thickness direction, and the fourth end of the negative electrode frame has a fourth number of negative electrolyte outlet holes along its thickness direction. Each of the positive electrolyte inlet hole, positive electrolyte outlet hole, negative electrolyte inlet hole, and negative electrolyte outlet hole has one or more flow channels extending from the inner wall of the hole to the inner wall of the electrode frame, allowing electrolyte to flow into or out of the electrode. This reduces the bypass current inside the flow battery stack, improving stack efficiency and reliability.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and more specifically to an electrode frame, a flow battery, and a flow battery stack. Background Technology

[0002] Energy storage, as a key technology for improving energy efficiency, is used in grid connection of renewable energy, peak shaving and valley filling, and peak and frequency regulation, thereby improving the utilization rate of renewable energy and enhancing grid stability. Flow batteries, due to their long lifespan, safety, reliability, and the ability to be individually designed for power and capacity, have become one of the main technologies for large-scale energy storage.

[0003] A flow battery typically consists of power units and capacity units. The electrolyte, acting as a capacity unit, stores and releases energy through changes in the valence states of its active substances. During operation, the electrolyte flows through the stack, which acts as the power unit, converting electrical energy into chemical energy, thus enabling power input and output.

[0004] Currently, flow batteries generally have low voltage levels, partly due to the influence of bypass current and partly because stacking more batteries would cause manufacturing difficulties. Summary of the Invention

[0005] The purpose of this invention is to provide an electrode frame, a flow battery, and a flow battery stack to solve the technical problem of the generally low voltage level of flow batteries.

[0006] To achieve the above objectives, embodiments of the present invention provide an electrode frame, including a positive electrode frame and a negative electrode frame superimposed by a first insulating layer. The first end of the positive electrode frame is provided with a first number of positive electrolyte inlet holes along the thickness direction, the second end of the positive electrode frame is provided with a second number of positive electrolyte outlet holes along the thickness direction, the third end of the negative electrode frame is provided with a third number of negative electrolyte inlet holes along the thickness direction, and the fourth end of the negative electrode frame is provided with a fourth number of negative electrolyte outlet holes along the thickness direction. The positive electrolyte inlet holes, the positive electrolyte outlet holes, the negative electrolyte inlet holes, and the negative electrolyte outlet holes are each provided with one or more flow channels from the inner wall of the hole to the inner wall of the electrode frame, so that electrolyte flows into or out of the electrode.

[0007] Optionally, the first quantity and the second quantity are the same, and / or the third quantity and the fourth quantity are the same.

[0008] Optionally, the first end and the second end are opposite ends, and / or the third end and the fourth end are opposite ends.

[0009] Optionally, the electrode frame is made of an acid-resistant polymer material, preferably one or more of the following materials: PVC, PP, PE.

[0010] Optionally, the electrode frame is formed by one of the following methods: machining, injection molding, compression molding, or 3D printing.

[0011] Accordingly, embodiments of the present invention also provide a flow battery, comprising a first electrode frame, a first positive electrode, a first negative electrode, a separator, a second negative electrode, a second positive electrode, and a second electrode frame stacked sequentially, wherein the first electrode frame and the second electrode frame are the electrode frames described above; the first positive electrode is embedded in the positive electrode frame of the first electrode frame, and the first negative electrode is embedded in the negative electrode frame of the first electrode frame, such that the first positive electrode and the first negative electrode are superimposed; the second positive electrode is embedded in the positive electrode frame of the second electrode frame, and the second negative electrode is embedded in the negative electrode frame of the second electrode frame, such that the second positive electrode and the second negative electrode are superimposed; in the flow battery, the stacking order of the first positive electrode and the first negative electrode is reversed compared to the stacking order of the second negative electrode and the second positive electrode, thereby making the flow battery comprise two sub-flow batteries stacked in opposite directions.

[0012] Optionally, the first positive electrode, the first negative electrode, the second negative electrode, and the second positive electrode are all the same size, and the dimensions of the first positive electrode, the first negative electrode, the second negative electrode, and the second positive electrode are all 100 cm. 2 -5000cm 2 100cm is preferred. 2 -2000cm 2 .

[0013] Accordingly, embodiments of the present invention also provide a flow battery stack, including: the flow battery described above; and a positive current output plate and a negative current output plate disposed at one end of the flow battery stack and superimposed by a first insulating layer, wherein the positive current output plate is used to output the positive current of the flow battery stack, and the negative current output plate is used to output the negative current of the flow battery stack.

[0014] Optionally, the flow battery stack includes one flow battery as described above, and the two sub-flow batteries are connected in series.

[0015] Optionally, the flow battery stack further includes a monopole plate disposed at the other end of the flow battery stack, and the two sub-flow batteries are connected in series through the monopole plate.

[0016] Optionally, the flow battery stack includes M flow batteries as described above, and the flow battery stack further includes: a first bipolar plate and a second bipolar plate disposed between two adjacent flow batteries and superimposed by a second insulating layer, so that the flow battery stack includes two sets of sub-flow batteries stacked in opposite directions, each set of sub-flow batteries including M sub-flow batteries, wherein the two sets of sub-flow batteries are connected in series, and M is a positive integer greater than 1.

[0017] Optionally, the flow battery stack further includes a monopole plate disposed at the other end of the flow battery stack, and the two sets of sub-flow batteries are connected in series through the monopole plate.

[0018] The electrode frame, flow battery, and flow battery stack provided in the embodiments of the present invention have the following technical advantages:

[0019] (1) When the electrode frame provided in this embodiment of the invention is applied to a flow battery, the two sub-flow batteries in the flow battery are supplied with electrolyte independently. When the flow battery is further applied to a flow battery stack, the flow battery stack is equivalent to using two independent electrolyte pipelines, which reduces the bypass current inside the flow battery stack and improves the stack efficiency and reliability.

[0020] (2) Compared with a flow battery stack formed by the same number of flow batteries in related technologies, the output voltage of a flow battery stack formed by using the flow batteries provided in the embodiments of the present invention can be increased by up to two times.

[0021] (3) The increase in the output voltage of the flow battery stack can promote the implementation of inverter and boost, reduce the difficulty of system integration, and make the flow battery stack more flexible in various scenarios.

[0022] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0024] Figure 1 A side view of an electrode frame according to an embodiment of the present invention is shown;

[0025] Figure 2 A schematic diagram of the flow channels on the electrode frame is shown;

[0026] Figure 3 A schematic diagram of a flow battery according to an embodiment of the present invention is shown;

[0027] Figure 4A schematic diagram of a flow battery stack according to an embodiment of the present invention is shown; and

[0028] Figure 5 It shows Figure 4 The discharge polarization curves of the shown flow battery stack are compared with those of flow battery stacks in related technologies. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustrating and explaining the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0030] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0031] Furthermore, if the embodiments of this invention involve descriptions such as "first," "second," and "third," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," and "third" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0032] Figure 1 A side view of an electrode frame according to an embodiment of the present invention is shown. Figure 1 As shown, an embodiment of the present invention provides an electrode frame, which may include a positive electrode frame 110 and a negative electrode frame 120 superimposed by a first insulating layer 130.

[0033] The first insulating layer 130 serves two purposes: insulation and isolation from the electrolyte. The first insulating layer 130 can be formed by sealing, injection molding, 3D printing, or welding.

[0034] The first end of the positive electrode frame 110 is provided with a first number of positive electrolyte inlet holes 111 along the thickness direction, and the positive electrolyte inlet holes are through holes. Figure 1 Two positive electrode electrolyte inlet holes are shown in the diagram. This is for illustrative purposes only. Any suitable number of positive electrode electrolyte inlet holes can be provided on the first end according to its length, or any suitable number of positive electrode electrolyte inlet holes can be provided on the first end according to actual needs. Each positive electrode electrolyte inlet hole 111 is provided with one or more flow channels 113 from the inner wall of the hole to the inner wall of the electrode frame, so that the positive electrode electrolyte flows into the electrode.

[0035] The second end of the positive electrode frame 110 is provided with a second number of positive electrolyte outlet holes 112 along the thickness direction, and the positive electrolyte outlet holes are through holes. Figure 1 Two positive electrode electrolyte outlet holes are shown in the diagram. This is for illustrative purposes only. Any suitable number of positive electrode electrolyte outlet holes can be provided on the second end depending on its length, or any suitable number of positive electrode electrolyte outlet holes can be provided on the second end as needed. Each positive electrode electrolyte outlet hole 112 is provided with one or more flow channels 114 from the inner wall of the hole to the inner wall of the electrode frame, so that the positive electrode electrolyte flows into the electrode.

[0036] like Figure 1 As shown, the first end and the second end are preferably opposite ends to facilitate smoother inflow and outflow of the positive electrolyte. However, this embodiment of the invention is not limited to this, and the first end and the second end can also be adjacent ends. The first quantity and the second quantity are preferably the same to facilitate smoother inflow and outflow of the positive electrolyte. However, this embodiment of the invention is not limited to this, and the first quantity and the second quantity can also be different.

[0037] The third end of the negative electrode frame 120 is provided with a third number of negative electrolyte inlet holes 121 in the thickness direction, and the negative electrolyte inlet holes are through holes. Figure 1 Two negative electrode electrolyte inlet holes are shown in the diagram. This is for illustrative purposes only. Any suitable number of negative electrode electrolyte inlet holes can be provided on the third end according to its length, or any suitable number of negative electrode electrolyte inlet holes can be provided on the third end as needed. Each negative electrode electrolyte inlet hole 121 is provided with one or more flow channels 123 from the inner wall of the hole to the inner wall of the electrode frame, so that the negative electrode electrolyte flows into the electrode.

[0038] The fourth end of the negative electrode frame 120 is provided with a fourth number of negative electrolyte outlet holes 122 along the thickness direction, and the negative electrolyte outlet holes are through holes. Figure 1Two negative electrode electrolyte outlet holes are shown in the diagram. This is for illustrative purposes only. Any suitable number of negative electrode electrolyte outlet holes can be provided on the fourth end depending on its length, or any suitable number of negative electrode electrolyte outlet holes can be provided on the fourth end as needed. Each negative electrode electrolyte outlet hole 122 is provided with one or more flow channels 124 from the inner wall of the hole to the inner wall of the electrode frame, so that the negative electrode electrolyte flows out of the electrode.

[0039] A schematic diagram of flow channels 113, 114, 123, and 124 can be shown as follows: Figure 2 As shown. The number of flow channels can be set to any suitable number according to actual needs.

[0040] like Figure 1 As shown, the third and fourth ends are preferably opposite ends to facilitate smoother inflow and outflow of the positive electrolyte. However, this embodiment of the invention is not limited to this, and the third and fourth ends can also be adjacent ends. The number of third and fourth ends is preferably the same to facilitate smoother inflow and outflow of the negative electrolyte. However, this embodiment of the invention is not limited to this, and the number of third and fourth ends can also be different.

[0041] like Figure 1 As shown, the first end and the third end can be on the same side of the electrode frame, and the second end and the fourth end can also be on the same side of the electrode frame. However, the embodiments of the present invention are not limited to this, and the first end and the fourth end can also be on the same side, and the second end and the third end can also be on the same side.

[0042] In any embodiment, the electrode frame may be made of an acid-resistant polymer material, which may be one or more of the following materials: PVC, PP, PE, etc.

[0043] In any embodiment, the electrode frame can be formed by machining, injection molding, compression molding, 3D printing, etc.

[0044] When the electrode frame provided in this embodiment of the invention is applied to a flow battery, it enables the two sub-flow batteries in the flow battery to be supplied with electrolyte independently. When the flow battery is further applied to a flow battery stack, the flow battery stack is equivalent to using two independent sets of electrolyte pipelines, which reduces the bypass current inside the flow battery stack and improves the stack efficiency and reliability.

[0045] Figure 3 A schematic diagram of a flow battery according to an embodiment of the present invention is shown. Figure 3 As shown, this embodiment of the invention also provides a flow battery, including a first electrode frame 11, a first positive electrode 12, a first negative electrode 16, a separator 13, a second negative electrode 14, a second positive electrode 17, and a second electrode frame 15 stacked in sequence.

[0046] The first electrode frame 11 and the second electrode frame 15 can be the electrode frames described in any embodiment of the present invention. The first positive electrode 12 is embedded in the positive electrode frame of the first electrode frame, and the first negative electrode 16 is embedded in the negative electrode frame of the first electrode frame, such that the first positive electrode 12 and the first negative electrode 16 are superimposed; the second positive electrode 14 is embedded in the positive electrode frame of the second electrode frame, and the second negative electrode 17 is embedded in the negative electrode frame of the second electrode frame, such that the second positive electrode 14 and the second negative electrode 17 are superimposed.

[0047] In the flow battery, the stacking order of the first positive electrode 12 and the first negative electrode 16 is the opposite of the stacking order of the second negative electrode 14 and the second positive electrode 17, so that the flow battery includes two sub-flow batteries stacked in opposite directions.

[0048] Both the first electrode frame 11 and the second electrode frame 15 can be the electrode frames described in any embodiment of the invention, such as... Figure 3 As shown. The first electrode frame 11 includes a first positive electrode frame and a first negative electrode frame stacked together by a first insulating layer. The second electrode frame 15 includes a second positive electrode frame and a second negative electrode frame stacked together by a second insulating layer. The first positive electrode frame of the first electrode frame 11 is stacked with the first positive electrode 12 to allow the positive electrolyte to flow into the first positive electrode 12. The first negative electrode frame of the first electrode frame 11 is stacked with the first negative electrode 16 to allow the negative electrode solution to flow into the first negative electrode 16. The second positive electrode frame of the second electrode frame 15 is stacked with the second positive electrode 17 to allow the positive electrolyte to flow into the second positive electrode 17. The second negative electrode frame of the second electrode frame 15 is stacked with the second negative electrode 14 to allow the negative electrode solution to flow into the second negative electrode 14.

[0049] Each sub-flow battery can be considered to be formed by sequentially stacking a first electrode frame 11, a sub-positive electrode, a separator 13, a sub-negative electrode aligned in position with the sub-positive electrode, and a second electrode frame 15. In any embodiment of the present invention, the direction of "stacking" is perpendicular to the direction of "layering". For example... Figure 1 As shown, the direction of "layering" is horizontal, and the direction of "overlay" is vertical. "Reverse overlay order" means that the first positive electrode 12 and the second negative electrode 14 are aligned in the overlay direction, and the first negative electrode 16 and the second positive electrode 17 are aligned. "Reverse overlay" means that the positive electrode of the first sub-flow battery and the negative electrode of the second sub-flow battery are overlaid in the two sub-flow batteries.

[0050] The flow battery may also include sealing components located around the positive and negative electrodes to prevent electrolyte from seeping to the outside of the flow battery and corroding it.

[0051] The first positive electrode 12, the first negative electrode 16, the second negative electrode 14, and the second positive electrode 17 are preferably identical, for example, they are identical in size and material. The dimensions of the first positive electrode 12, the first negative electrode 16, the second negative electrode 14, and the second positive electrode 17 are 100 cm². 2 -5000cm 2 100cm is preferred. 2 -2000cm 2 .

[0052] Although the embodiments of this invention describe a flow battery comprising two counter-stacked sub-flow batteries, it is understood that in extended embodiments, the flow battery may also comprise more than two counter-stacked sub-flow batteries, the structure of which can be derived from the structure of the flow battery comprising two counter-stacked sub-flow batteries described above, and will not be repeated here.

[0053] In a further embodiment of the present invention, a flow battery stack is provided, comprising: a flow battery according to any embodiment of the present invention; and a positive current output plate and a negative current output plate disposed at one end of the flow battery stack and superimposed by a first insulating layer, wherein the positive current output plate is used to output the positive current of the flow battery stack, and the negative current output plate is used to output the negative current of the flow battery stack.

[0054] The first insulating layer ensures that there is no electrical connection, short circuit, or leakage between the stacked positive and negative current-conducting plates. The first insulating layer can be made of any suitable insulating material.

[0055] At the other end of the flow battery stack, the positive and negative electrodes are connected in series, which enables the output voltage of the flow battery stack provided in this embodiment of the invention to be increased by up to two times compared to a flow battery stack formed by the same number of flow batteries in related technologies.

[0056] In an alternative embodiment, the flow battery stack may include a flow battery according to any embodiment of the present invention.

[0057] Optionally, in this embodiment, the flow battery stack may further include a single plate disposed at the other end of the flow battery stack. The single plate is used to connect the positive electrode and the negative electrode at the other end of the flow battery stack in series, thereby realizing the series connection of two sub-flow batteries of the flow battery. However, the embodiments of the present invention are not limited thereto. For example, the flow battery stack may include a first single plate and a second single plate disposed at the other end of the flow battery stack and superimposed by an insulating layer. Furthermore, the first single plate and the second single plate may be connected in series by an external circuit.

[0058] A first polymer plate can be further disposed on the outer side of the superimposed positive and negative current-delivering plates. This first polymer plate has a flow channel interface, through which the positive electrolyte can be supplied to the first and second electrode frames, for example. A second polymer plate can be further disposed on the outer side of the single-electrode plate. This second polymer plate also has a flow channel interface, through which the negative electrolyte can be supplied to the first and second electrode frames, for example. The components of the flow battery stack can be fastened or fixed by bolts or welding. The first and second polymer plates are made of polymer materials.

[0059] The output voltage of the flow battery stack provided in this embodiment of the invention is twice that of a flow battery stack including a single flow battery in the related art.

[0060] In an optional embodiment, the flow battery stack may include M flow batteries according to any embodiment of the present invention, where M is a positive integer greater than 1. Accordingly, the flow battery stack provided in the embodiments of the present invention may further include a first bipolar plate and a second bipolar plate disposed between two adjacent flow batteries and stacked together by a second insulating layer, thereby the flow battery stack includes two sets of sub-flow batteries stacked in opposite directions, each set of sub-flow batteries including M sub-flow batteries. The number of bipolar plates is the number of flow batteries minus one. Each bipolar plate has a positive electrode and a negative electrode adjacent to its two sides, respectively. Each bipolar plate can be used to connect two adjacent sub-flow batteries in series in the stacking direction.

[0061] Optionally, in this embodiment, the flow battery stack may further include a single plate disposed at the other end of the flow battery stack. The single plate is used to connect the positive electrode and the negative electrode at the other end of the flow battery stack in series, thereby realizing the series connection of two sets of sub-flow batteries. However, the embodiments of the present invention are not limited thereto. For example, the flow battery stack may include a first single plate and a second single plate disposed at the other end of the flow battery stack and superimposed by an insulating layer. Furthermore, the first single plate and the second single plate may be connected in series by an external circuit.

[0062] A first polymer plate can be further disposed on the outer side of the superimposed positive and negative current-delivering plates. This first polymer plate has a flow channel interface, through which positive electrolyte can be supplied to the first and second electrode frames of each flow battery, for example. A second polymer plate can be further disposed on the outer side of each single-electrode plate. This second polymer plate also has a flow channel interface, through which negative electrolyte can be supplied to the first and second electrode frames of each flow battery, for example. The components of the flow battery stack can be fastened or fixed by bolts or welding. The first and second polymer plates are made of polymer materials.

[0063] The second insulating layer ensures that there is no electrical connection, short circuit, or leakage between the stacked first and second bipolar plates. The first insulating layer can be made of any suitable insulating material. The second insulating layer can be made of the same or different materials as the first insulating layer.

[0064] The first bipolar plate, the second bipolar plate, the positive current conduction plate, the negative current conduction plate, and the monopolar plate can all be made of the same conductive material, such as graphite. The dimensions of the first bipolar plate, the second bipolar plate, the positive current conduction plate, the negative current conduction plate, and the monopolar plate can be adjusted according to the dimensions of the positive and negative electrodes.

[0065] In this embodiment, the two sets of sub-flow batteries are connected in series. Since the sub-flow batteries in each set are also connected in series, it is equivalent to each sub-flow battery being connected in series with the others.

[0066] Furthermore, the external structure and dimensions of the flow battery stack provided in this embodiment of the invention can be kept the same as those of the flow battery stack in the related art, thereby facilitating the replacement of the flow battery stack in the related art. Additionally, the flow battery stack provided in this embodiment of the invention can also be considered as a division of components within the flow battery stack, wherein the electrode frame, electrodes, bipolar plates, and one-end monopolar plates are uniformly divided into two pieces. The division direction of each component is consistent, and the division positions can be on the same horizontal line. The gaps between the divided electrodes are filled with a sealing layer, and the gaps between the divided electrode frame, bipolar plates, and one-end monopolar plates are filled with an insulating layer. The division or non-division of other components in the flow battery stack will not affect the high voltage output of the flow battery stack; therefore, it is preferable not to divide these other components, such as the separator and the monopolar plate at the other end.

[0067] The segmentation is equivalent to forming two small battery stacks in the stacking direction of the flow battery stack. The monopole plate at the other end, which is not segmented, is used to connect these two small battery stacks in series. The terminal voltage output of the flow battery stack will be twice that of an unsegmented flow battery stack of the same type. It is understood that the "segmentation" here is merely an analogy. In actual applications, the flow battery stack provided in this embodiment is not formed using a "segmentation" method. During initial design or actual production, the "segmented" components are preferably formed using the "stacked" method described above. Furthermore, in this embodiment, Figure 1 The "segmentation" or "overlay" directions shown are for illustrative purposes only and can be expanded to apply to individual components in relation to each other. Figure 1 The "segmentation" or "overlay" direction shown is perpendicular to the direction of "segmentation" or "overlay".

[0068] Optionally, the flow battery stack provided in the embodiments of the present invention can be an all-vanadium redox flow battery stack, a flow battery stack of other systems, or a single flow battery stack.

[0069] In related technologies, the components in flow batteries or flow battery stacks are not "segmented" or "stacked". Compared to flow battery stacks formed by the same number of flow batteries in related technologies, the output voltage of flow battery stacks formed using the flow batteries provided in this invention can be increased by two times, while maintaining the external structure and size unchanged.

[0070] The beneficial effects of the flow battery stack provided in the embodiments of the present invention will be further described below through some specific examples. In these examples, the flow battery stack is an all-vanadium redox flow battery stack.

[0071] Example 1

[0072] like Figure 4 As shown, in this embodiment, the flow battery stack consists of three flow batteries. Each flow battery includes: a first electrode frame stacked sequentially, a first positive electrode and a first negative electrode stacked through a first sealing layer, a separator, a second negative electrode and a second positive electrode stacked through a second sealing layer, and a second electrode frame, wherein the first electrode frame and the second electrode frame are both electrode frames as described in any embodiment of the present invention. A first bipolar plate and a second bipolar plate stacked through a second insulating layer are disposed between two adjacent flow batteries. A stacked positive current-conducting plate and a negative current-conducting plate are disposed at one end of the flow battery stack. A single plate is disposed at one end of the flow battery stack. A first polymer plate may be further disposed on the outside of the stacked positive current-conducting plate and the negative current-conducting plate, and a second polymer plate may be further disposed on the outside of the single plate. The flow battery stack is equivalent to being formed by stacking two sets of sub-flow batteries, each set of sub-flow batteries including three sub-flow batteries.

[0073] The positive current of the flow battery stack is extracted through the positive current extraction plate, and the negative current of the flow battery stack is extracted through the negative current extraction plate.

[0074] In this embodiment, the total area of ​​the positive and negative electrodes is 200 cm². 2 The corresponding areas of the first positive electrode, first negative electrode, second negative electrode, and second positive electrode are all 100 cm². 2 .

[0075] The initial concentration of the positive electrode electrolyte in the flow battery stack is 0.8 mol L. -1 V(IV) + 0.8 mol L -1 V(IV) + 3mol L -1 H2SO4, negative electrode electrolyte concentration is 0.8 mol / L -1 V(II) + 0.8 mol L -1 V(III) + 3mol L -1 H2SO4.

[0076] Because the sub-flow cells are connected in series, the potential at the positive electrode of each sub-flow cell increases progressively. For example... Figure 2 As shown, starting from the negative electrode, the potentials at the positive electrodes of the sequentially connected sub-flow batteries are 1*OCP, 2*OCP, 3*OCP, 4*OCP, 5*OCP, and 6*OCP, respectively. Therefore, in this embodiment, the flow battery stack can output a voltage of 6*OCP, where OCP represents the open-circuit potential.

[0077] Comparative Example 1

[0078] This embodiment describes a flow battery stack in the related art. In this embodiment, N=1, and the flow battery stack consists of three flow batteries. Each flow battery includes: a positive electrode frame, a positive electrode, a separator, a negative electrode, and a negative electrode frame stacked sequentially. A bipolar plate is disposed between two adjacent flow batteries. A positive end plate and a negative end plate are disposed at both ends of the flow battery. The positive end plate includes a positive current discharge plate and a first polymer plate, and the negative end plate includes a negative current discharge plate and a second polymer plate.

[0079] In this embodiment, the total area of ​​the positive and negative electrodes is 200 cm². 2 The discharge polarization performance of a flow battery stack can be measured using a potentiostat.

[0080] The initial concentration of the positive electrode electrolyte in the flow battery stack is 0.8 mol L. -1 V(IV) + 0.8 mol L -1 V(IV) + 3mol L-1 H2SO4, negative electrode electrolyte concentration is 0.8 mol / L -1 V(II) + 0.8 mol L -1 V(III) + 3mol L -1 H2SO4.

[0081] Based on a similar principle to Example 1, in this example, the flow battery stack can output a voltage of 6*OCP. It is readily apparent that, compared to the comparative example, the output voltage of the flow battery stack in Example 1 is increased by two times.

[0082] Figure 5 It shows Figure 4 The discharge polarization curves of the shown flow battery stack are compared with those of flow battery stacks in related technologies. From Figure 5 As can be seen from the figure, the working voltage of the fuel cell stack in the embodiment is twice that of the working voltage of the fuel cell stack in the comparative example, which verifies that the fuel cell stack using the structure of the embodiment of the present invention can double the working voltage of the fuel cell stack of the same scale as the comparative example structure.

[0083] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0084] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. An electrode frame, characterized in that, This includes a positive electrode frame and a negative electrode frame superimposed through a first insulating layer. The first end of the positive electrode frame is provided with a first number of positive electrolyte inlet holes along the thickness direction, and the second end of the positive electrode frame is provided with a second number of positive electrolyte outlet holes along the thickness direction. The third end of the negative electrode frame is provided with a third number of negative electrode electrolyte inlet holes along the thickness direction, and the fourth end of the negative electrode frame is provided with a fourth number of negative electrode electrolyte outlet holes along the thickness direction. The positive electrode electrolyte inlet hole, the positive electrode electrolyte outlet hole, the negative electrode electrolyte inlet hole, and the negative electrode electrolyte outlet hole are each provided with one or more flow channels from the inner wall of the hole to the inner wall of the electrode frame, so that the electrolyte flows into or out of the electrode.

2. The electrode frame according to claim 1, characterized in that, The first quantity is the same as the second quantity, and / or the third quantity is the same as the fourth quantity.

3. The electrode frame according to claim 1, characterized in that, The first end and the second end are opposite ends, and / or the third end and the fourth end are opposite ends.

4. The electrode frame according to claim 1, characterized in that, The electrode frame is made of an acid-resistant polymer material, which is one or more of the following materials: PVC, PP, PE.

5. The electrode frame according to claim 1, characterized in that, The electrode frame is formed by one of the following methods: injection molding, compression molding, or 3D printing.

6. A flow battery, characterized in that, It includes a first electrode frame, a first positive electrode, a first negative electrode, a diaphragm, a second negative electrode, a second positive electrode, and a second electrode frame, which are sequentially stacked. The first electrode frame and the second electrode frame are the electrode frames according to any one of claims 1 to 5; The first positive electrode is embedded in the positive electrode frame of the first electrode frame, and the first negative electrode is embedded in the negative electrode frame of the first electrode frame, so that the first positive electrode and the first negative electrode are superimposed. The second positive electrode is embedded in the positive electrode frame of the second electrode frame, and the second negative electrode is embedded in the negative electrode frame of the second electrode frame, so that the second positive electrode and the second negative electrode are superimposed. In the flow battery, the stacking order of the first positive electrode and the first negative electrode is the opposite of the stacking order of the second negative electrode and the second positive electrode, so that the flow battery includes two sub-flow batteries stacked in reverse order.

7. The flow battery according to claim 6, characterized in that, The first positive electrode, the first negative electrode, the second negative electrode, and the second positive electrode have the same dimensions, and The dimensions of the first positive electrode, the first negative electrode, the second negative electrode, and the second positive electrode are all 100 cm. 2 -5000cm 2 .

8. A flow battery stack, characterized in that, include: The flow battery according to any one of claims 6 to 7; as well as A positive current extraction plate and a negative current extraction plate are disposed at one end of the flow battery stack and superimposed through a first insulating layer. The positive current extraction plate is used to extract the positive current of the flow battery stack, and the negative current extraction plate is used to extract the negative current of the flow battery stack.

9. The flow battery stack according to claim 8, characterized in that, The flow battery stack includes a flow battery according to any one of claims 6 to 7, wherein the two sub-flow batteries are connected in series.

10. The flow battery stack according to claim 9, characterized in that, The flow battery stack also includes a monopole plate disposed at the other end of the flow battery stack, and the two sub-flow batteries are connected in series through the monopole plate.

11. The flow battery stack according to claim 8, characterized in that, The flow battery stack comprises M flow batteries according to any one of claims 6 to 7, and the flow battery stack further comprises: A first bipolar plate and a second bipolar plate are disposed between two adjacent flow batteries and stacked together by a second insulating layer, thereby the flow battery stack includes two sets of sub-flow batteries stacked in opposite directions, each set of flow batteries including M sub-flow batteries. The two sets of sub-flow batteries are connected in series. Where M is a positive integer greater than 1.

12. The flow battery stack according to claim 11, characterized in that, The flow battery stack also includes a monopole plate disposed at the other end of the flow battery stack, and the two sets of sub-flow batteries are connected in series through the monopole plate.

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