Flow battery and flow battery stack

Abstract

The embodiment of the present application provides a kind of liquid flow battery and liquid flow battery stack, belong to energy storage technical field.The liquid flow battery includes sequentially laminated positive electrode frame, positive electrode, diaphragm, negative electrode, negative electrode frame, the positive electrode includes N sub positive electrode, the N sub positive electrode is stacked by first insulating layer between adjacent two sub positive electrode, the negative electrode includes N sub negative electrode corresponding to the N sub positive electrode, the N sub negative electrode is stacked by second insulating layer between adjacent two sub negative electrode, so that the liquid flow battery is formed by N sub liquid flow battery superposition, wherein N is greater than 1 Positive integer.Compared with the liquid flow battery stack formed by the same number of liquid flow battery in the related art, the output voltage of the liquid flow battery stack formed by using the liquid flow battery provided by the embodiment of the present application can be improved by N times.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and more specifically to 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 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 a flow battery, comprising a positive electrode frame, a positive electrode, a separator, a negative electrode, and a negative electrode frame stacked sequentially. The positive electrode includes N sub-positive electrodes, with adjacent sub-positive electrodes stacked through a first insulating layer. The negative electrode includes N sub-negative electrodes corresponding one-to-one with the N sub-positive electrodes, with adjacent sub-negative electrodes stacked through a second insulating layer. Thus, the flow battery is formed by stacking N sub-flow batteries, where N is a positive integer greater than 1.

[0007] Optionally, the N sub-positive electrodes and the N sub-negative electrodes are of the same size.

[0008] Optionally, the size of each of the N sub-positive electrodes and each of the N sub-negative electrodes is 100 cm. 2 -5000cm 2 100cm is preferred. 2 -2000cm 2 .

[0009] Optionally, the first insulating layer and / or the second insulating layer are made of a porous insulating material.

[0010] Optionally, the porosity of the porous insulating material, the porosity of the N sub-positive electrodes, and the porosity of the N sub-negative electrodes are the same.

[0011] Accordingly, embodiments of the present invention also provide a flow battery stack, comprising: a flow battery as described above; a positive terminal plate and a negative terminal plate disposed at both ends of the flow battery stack, wherein the positive terminal plate includes a positive current discharge plate, and the negative terminal plate includes a negative current discharge plate, wherein the positive current discharge plate includes N sub-positive current discharge plates corresponding one-to-one with the N sub-positive electrodes, and the negative current discharge plate includes N sub-negative current discharge plates corresponding one-to-one with the N sub-negative electrodes, wherein adjacent two sub-positive current discharge plates are stacked together by a third insulating layer, and adjacent two negative current discharge plates are stacked together by a fourth insulating layer.

[0012] Optionally, the flow battery stack includes one flow battery as described above, and the N sub-flow batteries are connected in series.

[0013] Optionally, the flow battery stack includes M flow batteries as described above, and the flow battery stack further includes: bipolar plates disposed between two adjacent flow batteries, wherein the bipolar plates include N sub-bipolar plates corresponding one-to-one with the N sub-positive electrodes, and adjacent two sub-bipolar plates are stacked together by a fifth insulating layer, so that the flow battery stack is formed by stacking N groups of sub-flow batteries, each group of sub-flow batteries including M sub-flow batteries, where M is a positive integer greater than 1.

[0014] Optionally, the N sub-flow batteries are connected in series.

[0015] Optionally, the third insulating layer, the fourth insulating layer, and the fifth insulating layer are formed by sealing or welding.

[0016] In the flow battery provided by this invention, the positive electrode is formed by N (N is a positive integer greater than 1) sub-positive electrodes stacked together through a first insulating layer, and the negative electrode is formed by N sub-negative electrodes stacked together with a second insulating layer corresponding to the N sub-positive electrodes. This is equivalent to a single flow battery being formed by stacking N sub-flow batteries. The flow battery has the following technical advantages:

[0017] (1) 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 N times.

[0018] (2) 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.

[0019] 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

[0020] 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:

[0021] Figure 1 A schematic diagram of a flow battery according to an embodiment of the present invention is shown;

[0022] Figure 2 A schematic diagram of a flow battery stack according to an embodiment of the present invention is shown;

[0023] Figure 3 A schematic diagram of a flow battery stack according to another embodiment of the present invention is shown;

[0024] Figure 4 It shows Figure 2 and Figure 3 The discharge polarization curves of the shown flow battery stack are compared with those of flow battery stacks in related technologies. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0026] Figure 1 A schematic diagram of a flow battery according to an embodiment of the present invention is shown. Figure 1As shown, this embodiment of the invention provides a flow battery, including a positive electrode frame 11, a positive electrode, a separator 13 (also called an ion exchange membrane), a negative electrode, and a negative electrode frame 15 stacked sequentially. The positive electrode may include N sub-positive electrodes 12, where adjacent sub-positive electrodes 12 are stacked through a first insulating layer 16. The negative electrode may include N sub-negative electrodes 14, where adjacent sub-negative electrodes 14 are stacked through a second insulating layer 17, thereby forming the flow battery from N sub-flow batteries. Each sub-flow battery can be considered as being formed by sequentially stacking a positive electrode frame 11, a sub-positive electrode, a separator 13, a sub-negative electrode aligned in position with the sub-positive electrode, and a negative electrode frame 15. In any embodiment of the invention, N is a positive integer greater than 1. The direction of "stacking" described in any embodiment of the invention is perpendicular to the direction of "layering". For example... Figure 1 As shown, the direction of "layering" is horizontal, and the direction of "overlaying" is vertical.

[0027] Flow batteries 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.

[0028] The positive electrode frame 11 is provided with a flow channel for introducing positive electrolyte into the positive electrode. Correspondingly, the negative electrode frame 15 is provided with a flow channel for introducing negative electrolyte into the negative electrode. Figure 1 The example shown illustrates a flow battery comprising an integral positive electrode frame 11 and an integral negative electrode frame 15. In an alternative embodiment, the flow battery may include one or more positive electrode frames corresponding to N sub-positive electrodes 12 and one or more negative electrode frames corresponding to N sub-negative electrodes 14. For example, the flow battery may include N positive electrode frames corresponding one-to-one with the N sub-positive electrodes 12, each positive electrode frame introducing a positive electrolyte into the corresponding sub-positive electrode; correspondingly, the flow battery may also include N negative electrode frames corresponding one-to-one with the N sub-negative electrodes 14, each negative electrode frame introducing a negative electrolyte into the corresponding sub-negative electrode.

[0029] The N sub-positive electrodes 12 and N sub-negative electrodes 14 are preferably identical, for example, each sub-positive electrode 12 and each sub-negative electrode 14 has the same size and material. The size of each sub-positive electrode 12 and each sub-negative electrode 14 can be 100 cm. 2 -5000cm 2 100cm is preferred. 2 -2000 cm 2 .

[0030] The first insulating layer ensures that there is no electrical connection or short circuit between adjacent positive electrodes. The second insulating layer ensures that there is no electrical connection or short circuit between adjacent negative electrodes.

[0031] The first and second insulating layers are preferably made of the same insulating material. Specifically, the first and second insulating layers can be made of a porous insulating material. Preferably, the porosity of the porous insulating material, the porosity of the N sub-positive electrodes, and the porosity of the N sub-negative electrodes are the same to ensure that the flow resistance generated by the insulating layer, the sub-positive electrodes, and the sub-negative electrodes is the same, thereby ensuring uniform electrolyte flow. In some other embodiments, the first and second insulating layers can also be made of different insulating materials; or the porosity of the porous insulating material used to make the first insulating layer and the porous insulating material used to make the second insulating layer can be different; or the porosity of the porous insulating material, the porosity of the N sub-positive electrodes, and the porosity of the N sub-negative electrodes can be different.

[0032] 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; a positive terminal plate and a negative terminal plate disposed at both ends of the flow battery stack, wherein the positive terminal plate includes a positive current discharge plate, and the negative terminal plate includes a negative current discharge plate, wherein the positive current discharge plate includes N sub-positive current discharge plates corresponding one-to-one with the N sub-positive electrodes, and the negative current discharge plate includes N sub-negative current discharge plates corresponding one-to-one with the N sub-negative electrodes, wherein adjacent two sub-positive current discharge plates are stacked by a third insulating layer, and adjacent two negative current discharge plates are stacked by a fourth insulating layer.

[0033] In an optional embodiment, the flow battery stack may consist of a flow battery according to any embodiment of the present invention, a positive electrode plate, and a negative electrode plate disposed at both ends. The positive electrode plate includes a positive current-conducting plate and a first polymer plate located outside the positive current-conducting plate; correspondingly, the negative electrode plate includes a negative current-conducting plate and a second polymer plate located outside the negative current-conducting plate. The first polymer plate is provided with a flow channel interface, which communicates with the flow channel of the positive electrode frame, through which the positive electrolyte flows into the flow channel of the positive electrode frame. The second polymer plate is provided with a flow channel interface, which communicates with the flow channel of the negative electrode frame, through which the negative electrolyte flows into the flow channel of the negative electrode frame. The components of the flow battery stack may be fastened or fixed by bolts or welding.

[0034] The third insulating layer ensures that there is no electrical connection or short circuit between adjacent positive current-draining plates. The fourth insulating layer ensures that there is no electrical connection or short circuit between adjacent negative current-draining plates. The third and fourth insulating layers can be made of the same insulating material, for example, by sealing, welding, or other forms of insulating material.

[0035] In this embodiment, the N sub-flow batteries of the flow battery stack can be connected in series via an external circuit. Specifically, the series connection of the N sub-flow batteries can be achieved by electrically connecting the positive current output plate and the negative current output plate of each sub-flow battery.

[0036] 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 may also include bipolar plates disposed between two adjacent flow batteries, wherein each bipolar plate includes N sub-bipolar plates corresponding one-to-one with the N sub-positive electrodes. Adjacent sub-bipolar plates are stacked together by a fifth insulating layer, such that the flow battery stack is formed by stacking N groups of sub-flow batteries, each group including M sub-flow batteries. The number of bipolar plates is the number of flow batteries minus one. Each sub-bipolar plate can be used to connect two adjacent sub-flow batteries in series.

[0037] In this embodiment, the positive electrode plate includes a positive current-conducting plate and a first polymer plate located outside the positive current-conducting plate. Similarly, the negative electrode plate includes a negative current-conducting plate and a second polymer plate located outside the negative current-conducting plate. The first polymer plate has a flow channel interface that connects to the flow channel of the positive electrode frame, through which the positive electrolyte flows into the flow channel of the positive electrode frame. The second polymer plate has a flow channel interface that connects to the flow channel of the negative electrode frame, through which the negative electrolyte flows into the flow channel of the negative electrode frame. The components of the flow battery stack can be fastened or fixed by bolts or welding.

[0038] The fifth insulating layer is used to ensure that there is no electrical connection or short circuit between adjacent sub-bipolar plates. The fifth, third, and fourth insulating layers can be made of the same insulating material, for example, they can be made by sealing, welding, or other forms of insulating material.

[0039] The sub-bipolar plate, sub-positive current-deducting plate, and sub-negative current-deducting plate can all be made of graphite, or they can be made of graphite plates combined with metal conductors. The dimensions of the sub-bipolar plate, sub-positive current-deducting plate, and sub-negative current-deducting plate can be 100 cm². 2 -5000cm 2 100cm is preferred. 2-2000cm 2 .

[0040] In this embodiment, N sub-flow batteries are connected in series. Specifically, the series connection between each sub-flow battery in the N sub-flow batteries can be achieved by electrically connecting the positive electrode current-delivering plate and the negative electrode current-delivering plate. Since the sub-flow batteries in each sub-flow battery group are also connected in series, it is equivalent to each sub-flow battery being connected in series with each other.

[0041] 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 positive electrode, negative electrode, bipolar plate, positive current extraction plate, and negative current extraction plate are each uniformly divided into N parts, and the division positions of each component can be on the same horizontal line. The gaps between the positive and negative electrodes are filled with an insulating layer made of porous insulating material with the same porosity as the positive and negative electrodes. The gaps between the bipolar plate, positive current extraction plate, and negative current extraction plate are filled with an insulating layer made of sealing, welding, or other forms of insulating material. The separation or non-separation 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 separate these other components. These other components include, for example, a separator, a positive electrode frame, a negative electrode frame, a first polymer plate and a second polymer plate disposed at both ends, etc. The flow channels of the positive electrode frame and the negative electrode frame can be kept the same as those of the positive electrode frame and the negative electrode frame in related technologies.

[0042] The segmentation is equivalent to forming N parallel miniature battery stacks in the stacking direction of the flow battery stack. By connecting these miniature battery stacks in series via an external circuit, the terminal voltage output by the flow battery stack will be N times that of an unsegmented flow battery stack of the same type. It is understood that the term "segmentation" here is merely an analogy. In practical 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.

[0043] 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.

[0044] In related technologies, the value of N in flow batteries or flow battery stacks is 1. Compared with 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 embodiment of the invention can be increased by N times, while maintaining the external structure and size unchanged.

[0045] The beneficial effects of the flow battery stack provided in the embodiments of the present invention will be further described below through some examples. In these examples, the flow battery stack is an all-vanadium redox flow battery stack.

[0046] Example 1

[0047] like Figure 2 As shown, in this embodiment, N=2, 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. The positive electrode includes a first sub-positive electrode and a second sub-positive electrode stacked through a first insulating layer, and the negative electrode includes a first sub-negative electrode and a second sub-negative electrode stacked through a second insulating layer. A bipolar plate is disposed between two adjacent flow batteries, and the bipolar plate correspondingly includes a first sub-bipolar plate and a second sub-bipolar plate stacked through a fifth insulating layer. Positive and negative terminal plates are disposed at both ends of the flow battery. The positive terminal plate includes a positive current discharge plate and a first polymer plate, and the negative terminal plate includes a negative current discharge plate and a second polymer plate. The positive current discharge plate includes a first sub-positive current discharge plate and a second sub-positive current discharge plate stacked through a third insulating layer, and the negative current discharge plate includes a first sub-negative current discharge plate and a second sub-negative current discharge plate stacked through a fourth insulating layer. This results in the flow battery stack being formed by stacking two groups of sub-flow batteries, with each group of sub-flow batteries comprising three sub-flow batteries.

[0048] The first sub-positive current output board is electrically connected to the second sub-negative current output board, and a positive voltage is output through the second sub-positive current output board and a negative voltage is output through the first sub-negative current output board; or the second sub-positive current output board is electrically connected to the first sub-negative current output board, and a positive voltage is output through the first sub-positive current output board and a negative voltage is output through the second sub-negative current output board.

[0049] In this embodiment, the total area of ​​the positive and negative electrodes is 200 cm². 2 The corresponding area of ​​each sub-positive electrode and each sub-negative electrode is 100 cm². 2 .

[0050] 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 -1V(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.

[0051] 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 sub-flow batteries connected in series 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.

[0052] Example 2

[0053] like Figure 3 As shown, in this embodiment, N=3, and the flow battery stack consists of 3 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. The positive electrode includes a first sub-positive electrode, a second sub-positive electrode, and a third sub-positive electrode stacked through a first insulating layer. The negative electrode includes a first sub-negative electrode, a second sub-negative electrode, and a third sub-negative electrode stacked through a second insulating layer. A bipolar plate is disposed between two adjacent flow batteries, and the bipolar plate correspondingly includes a first sub-bipolar plate, a second sub-bipolar plate, and a third sub-bipolar plate stacked through a fifth insulating layer. Positive and negative end plates 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. The positive electrode current-conducting plate includes a first sub-positive electrode current-conducting plate, a second sub-positive electrode current-conducting plate, and a third sub-positive electrode current-conducting plate stacked together through a third insulating layer. The negative electrode current-conducting plate includes a first sub-negative electrode current-conducting plate, a second sub-negative electrode current-conducting plate, and a third sub-negative electrode current-conducting plate stacked together through a fourth insulating layer. Thus, the flow battery stack is formed by stacking three groups of sub-flow batteries, with each group comprising three sub-flow batteries.

[0054] The second sub-negative current output board is electrically connected to the first sub-positive current output board, and the third sub-negative current output board is electrically connected to the second sub-positive current output board. Negative current is output through the first sub-negative current output board and positive current is output through the third sub-positive current output board.

[0055] In this embodiment, the total area of ​​the positive and negative electrodes is 200 cm². 2The corresponding area of ​​each sub-positive electrode and each sub-negative electrode is 66.7 cm². 2 .

[0056] 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.

[0057] Based on a similar principle to Example 1, in this example, the flow battery stack can output a voltage of 9*OCP.

[0058] Comparative Example 1

[0059] 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.

[0060] 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.

[0061] 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.

[0062] Based on a similar principle to Example 1, in this example, the flow battery stack can output a voltage of 3*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, and the output voltage of the flow battery stack in Example 2 is increased by three times.

[0063] Figure 4 It shows Figure 2 and Figure 3 The discharge polarization curves of the flow battery stack shown are compared with those of flow battery stacks in related technologies. It can be seen that the actual experiment verified that the operating voltage of the stacks in Example 1 and Example 2 is 2 times and 3 times that of the comparative examples, respectively, and is proportional to the number of sub-cells into which a single cell is divided.

[0064] 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.

[0065] 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. A flow battery, characterized in that, It includes a positive electrode frame, a positive electrode, a separator, a negative electrode, and a negative electrode frame stacked in sequence. The positive electrode includes N sub-positive electrodes, and two adjacent sub-positive electrodes are stacked through a first insulating layer. The negative electrode includes N sub-negative electrodes that correspond one-to-one with the N sub-positive electrodes, and two adjacent sub-negative electrodes are stacked through a second insulating layer, so that the flow battery is formed by stacking N sub-flow batteries. The first insulating layer and the second insulating layer are made of porous insulating material. Where N is a positive integer greater than 1, the direction in which the N sub-flow batteries are stacked is perpendicular to the direction in which the positive electrode frame, positive electrode, separator, negative electrode, and negative electrode frame are stacked, and the N sub-flow batteries are connected in series.

2. The flow battery according to claim 1, characterized in that, The N sub-positive electrodes and the N sub-negative electrodes are all the same size.

3. The flow battery according to claim 2, characterized in that, The size of each of the N sub-positive electrodes, each of the N sub-negative electrodes is 100 cm 2 - 5000 cm 2 .

4. The flow battery according to claim 2, characterized in that, The size of each of the N sub-positive electrodes, each of the N sub-negative electrodes is 100 cm 2 - 2000 cm 2 .

5. The flow battery according to claim 1, characterized in that, The porosity of the porous insulating material, the porosity of the N sub-positive electrodes, and the porosity of the N sub-negative electrodes are the same.

6. A flow battery stack, characterized in that, include: The flow battery according to any one of claims 1 to 5; The positive and negative terminal plates are disposed at both ends of the flow battery stack. The positive terminal plate includes a positive current discharge plate, and the negative terminal plate includes a negative current discharge plate. The positive current discharge plate includes N sub-positive current discharge plates corresponding to the N sub-positive electrodes, and the negative current discharge plate includes N sub-negative current discharge plates corresponding to the N sub-negative electrodes. Adjacent sub-positive current discharge plates are stacked together by a third insulating layer, and adjacent negative current discharge plates are stacked together by a fourth insulating layer.

7. The flow battery stack according to claim 6, characterized in that, The flow battery stack comprises M flow batteries according to any one of claims 1 to 5, and the flow battery stack further comprises: A bipolar plate is disposed between two adjacent flow batteries, wherein the bipolar plate includes N sub-bipolar plates corresponding one-to-one with the N sub-positive electrodes. Adjacent sub-bipolar plates are stacked together by a fifth insulating layer, such that the flow battery stack is formed by stacking N groups of sub-flow batteries, each group comprising M sub-flow batteries. Where M is a positive integer greater than 1.

8. The flow battery stack according to claim 7, characterized in that, The N sub-flow batteries are connected in series.

9. The flow battery stack according to claim 7, characterized in that, The third, fourth, and fifth insulating layers are formed by sealing or welding.

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