A flow battery stack

Abstract

The application discloses a liquid flow battery stack, and relates to the technical field of liquid flow batteries, wherein the stack comprises two or more parallelly arranged sub-stacks and a self-flowing guide pipe inserted into liquid interfaces of the sub-stacks, the self-flowing guide pipe comprises a plurality of concentrically arranged pipes, and the internal space of the innermost pipe and the annular space between adjacent pipes jointly form liquid channels consistent with the number of the sub-stacks and independent of each other; a plurality of lateral openings are arranged on the outermost pipe in the axial direction, one side of the lateral opening extending radially outward is in sealed communication with the liquid interface of one of the sub-stacks, the lateral opening extends radially inward, and is in communication with one of the liquid channels; and the lateral opening covers the liquid inlet or outlet of each single cell in the sub-stack in communication with the lateral opening. The application can realize simultaneous liquid supply of two or more single stacks, the electrolyte channels of each sub-stack are independent of each other and do not interfere with each other, and the application meets the high-power application scenario.

Description

Technical Field

[0001] This application relates to the field of flow battery technology, and in particular to a flow battery stack. Background Technology

[0002] A flow battery stack typically consists of end plates, insulating plates, current collectors, and multiple individual cells. The end plates are usually made of stainless steel and have screw holes. The two end plates are fastened together with screws and nuts to secure the multiple individual cells. The insulating plates isolate the end plates from the current collectors to prevent the end plates from becoming charged, while the current collectors conduct current.

[0003] There are two mainstream designs for existing fuel cell stacks: one is a single stack configuration, in which multiple single cells (generally no more than 30 single cells) are sandwiched between two liquid inlet plates, and the multiple single cells are fastened with end plates on the outside of the liquid inlet plates; the other is a dual stack combination, in which two single stack configurations eliminate the two end plates on opposite sides, but four independent liquid inlet plates are required for liquid supply; in addition, there are also solutions that attempt to integrate the liquid inlet function into the end plates, but due to the limited number of end plate channels, they can only support independent liquid supply for two single stacks.

[0004] It can be seen that the physical layout of the liquid inlet plate or end plate supply limits the scalability of the battery stack, resulting in existing flow battery stacks being generally limited to single or dual stack configurations. This makes it impossible to increase power output through simple stacking, which severely restricts the application of flow batteries in high-power scenarios. Summary of the Invention

[0005] The purpose of this application is to provide a flow battery stack that can simultaneously supply electrolyte to two or more individual stacks, with each sub-stack having an independent electrolyte channel that does not interfere with each other, thereby breaking through the bottleneck of existing stack structures in power expansion and meeting the needs of high-power application scenarios.

[0006] To achieve the above objectives, this application provides a flow battery stack, including two or more parallel sub-stacks and a self-diverting liquid guide tube inserted into multiple liquid interfaces of the sub-stacks. The self-diverting liquid guide tube includes multiple concentrically arranged pipes, the innermost pipe's internal space and the annular space between adjacent pipes, together forming a liquid channel that is the same number as the sub-stacks and independent of each other.

[0007] The outermost pipe has a plurality of lateral openings arranged axially. The radially outward side of the lateral opening is sealed and connected to the liquid interface of one of the sub-pile. The lateral opening extends radially inward and is connected to one of the liquid channels. The lateral opening covers the liquid inlet or outlet of each single cell in the sub-pile connected to it.

[0008] Optionally, the liquid channel is open at one end and closed at the other end;

[0009] The openings of the multiple liquid channels are located on the same side and at the same cross-section;

[0010] The lateral opening is located between the open end and the closed end of the liquid channel that is connected to it.

[0011] Optionally, along the axial direction from the open end to the closed end of the liquid channel, the lateral openings are sequentially connected to the outermost to the innermost liquid channels in the order of arrangement.

[0012] Optionally, in any of the liquid channels and the lateral openings communicating therewith, the closed end of the liquid channel corresponds to the side of the lateral opening away from the opening end of the liquid channel.

[0013] Optionally, multiple support columns are arranged between adjacent pipes, and the multiple support columns are evenly distributed along the circumference of the pipes.

[0014] Optionally, each of the liquid channels has the same flow cross-sectional area, and each of the lateral openings has the same size specifications.

[0015] Optionally, it also includes end plates located on both sides of the plurality of sub-charge stacks to clamp the plurality of sub-charge stacks;

[0016] The end plate is provided with a through hole corresponding to the liquid interface, and the self-diverting liquid guide tube is inserted into the liquid interface through the through hole.

[0017] Optionally, a sealing joint is fixedly provided in the through hole, one end of the sealing joint is sealed and connected to the opening end of the liquid channel, and the other end of the sealing joint is connected to an electrolyte.

[0018] Optionally, the sealing joint includes a hollow flow channel and an annular groove disposed on the outer periphery of the hollow flow channel;

[0019] The outermost pipe comprises an integrally formed outer tube and an inner tube, the outer tube extending axially beyond the opening end of the liquid channel, and the extended portion inserting into the annular groove;

[0020] The outer tube is interference-fitted with the annular groove, and the outer wall and / or inner wall of the outer tube are provided with a sealing ring that seals with the annular groove. The inner diameter of the hollow flow channel is the same as the inner diameter of the inner tube.

[0021] Optionally, the liquid interface includes a positive inlet, a negative inlet, a positive outlet, and a negative outlet located at the four corners of the sub-pile, with the positive inlet and positive outlet being diagonally distributed.

[0022] The liquid interfaces on the multiple sub-piles correspond to each other, and the multiple self-diverting liquid guide tubes are inserted into the corresponding liquid interfaces through different through holes, and the different lateral openings on the same self-diverting liquid guide tube are respectively connected to different sub-piles;

[0023] Multiple sub-pile stacks are connected in series, and current collectors are led out from the outermost positive and negative poles of the multiple sub-pile stacks. An insulating layer is provided between the end plate and the current collector.

[0024] The beneficial effects of this application are that, through the innovative design of two or more parallel sub-piles and self-diverting liquid guide pipes, the efficiency and independence of electrolyte distribution are achieved. This ensures that the independent liquid channels formed by the multiple concentric pipes of the self-diverting liquid guide pipe are connected to each sub-pile, and the electrolyte flow in each sub-pile does not interfere with each other. At the same time, the lateral opening can cover the liquid inlet or outlet of each single cell in the sub-pile connected to it, thereby simultaneously supplying or discharging liquid to multiple multi-cell single cells and avoiding the situation where the electrolyte flow rate in each single cell is inconsistent due to the series connection of multiple single cells. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the flow battery stack structure provided in the embodiments of this application;

[0027] Figure 2 This is a schematic diagram of the structure of the sub-pile and the self-diverting liquid guide tube provided in the embodiments of this application;

[0028] Figure 3 This is a schematic diagram of the self-diverting liquid guide tube structure provided in the embodiments of this application;

[0029] Figure 4 This is a cross-sectional view of the self-diverting liquid guide tube provided in an embodiment of this application;

[0030] Figure 5 This is a schematic diagram of the open end structure of the self-diverting liquid guide tube provided in an embodiment of this application;

[0031] Figure 6 This is a schematic diagram of the liquid interface distribution on the sub-pile provided in an embodiment of this application;

[0032] Figure 7 This is a schematic diagram of the current collector structure provided in an embodiment of this application;

[0033] Figure 8 Exploded views of the end plate, insulating layer, and current collector provided in the embodiments of this application;

[0034] Figure 9 This is a schematic diagram of the sealing joint structure provided in the embodiments of this application.

[0035] In the diagram: 1-Sub-pile; 2-End plate; 3-Self-diverting liquid guide tube; 4-Sealing joint; 5-Current collector; 6-Insulation layer;

[0036] 11-Liquid interface; 111-Positive outlet; 112-Negative inlet; 113-Positive inlet; 114-Negative outlet;

[0037] 21-Through hole;

[0038] 31-Pipe; 32-Open end; 33-Liquid passage; 34-Lateral opening; 35-Closed end; 36-Sealing ring; 37-Support column; 311-Outer pipe; 312-Inner pipe;

[0039] 41-Hollow flow channel; 42-Annular groove. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] It should be noted that in this embodiment, the orientation or positional relationship indicated by terms such as "upper," "lower," "front," and "rear" is based on the orientation or positional relationship shown in the accompanying drawings. It is used only for the convenience of describing this application and for simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application. Furthermore, "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] like Figures 1 to 9As shown, in this embodiment, a flow battery stack is provided, including two or more parallel-arranged sub-stacks 1 and a self-diverting liquid guide pipe 3 through which liquid interfaces 11 are inserted into the multiple sub-stacks 1; wherein, parallel arrangement means that the multiple sub-stacks 1 are arranged side by side in the thickness direction of the stack. By arranging multiple sub-stacks 1 in parallel, the limitations of traditional single / dual stack structures are overcome, supporting linear increase in stack power and meeting the needs of high-power applications.

[0044] Based on this, the liquid interfaces 11 of multiple sub-pile 1 correspond to each other and are located on the same axis; for example, when the liquid interface 11 is the positive inlet 113, the positive inlet 113 of each sub-pile 1 is located on the same axis. At this time, the self-diverting liquid guide tube 3 can be inserted into the liquid interface 11 from the side of the pile structure along the axial direction, and the self-diverting liquid guide tube 3 can be inserted into the liquid interface 11 of each pile in sequence.

[0045] Please refer to Figure 3 and Figure 4 The self-diverting liquid guide pipe 3 includes multiple concentrically arranged pipes 31. The internal space of the innermost pipe 31 and the annular space between adjacent pipes 31 together form liquid channels 33 that are the same number as the number of sub-pile 1 and independent of each other. Furthermore, multiple lateral openings 34 are arranged axially on the outermost pipe 31. The radially outward side of the lateral opening 34 is sealed and connected to the liquid interface 11 of one of the sub-pile 1. The lateral opening 34 extends radially inward and is connected to one of the liquid channels 33, so that each sub-pile 1 has its own dedicated liquid channel 33, ensuring that the electrolyte flow does not interfere with each other, eliminating the problem of uneven flow in traditional parallel / series connections, and improving the overall efficiency and consistency of the fuel cell stack.

[0046] The sealing method between the side opening 34 and the liquid channel 33 can be O-ring sealing or sealant sealing. For example, an O-ring or sealant can be wrapped around the side opening 34. After the self-diverting liquid guide tube 3 is inserted into the liquid interface 11, the O-ring or sealant around each side opening 34 can seal with the liquid interface 11 of the corresponding sub-fuel cell 1, thereby ensuring that the electrolyte of each side opening 34 can enter and exit the corresponding sub-fuel cell 1.

[0047] Furthermore, each lateral opening 34 can cover the liquid inlet or outlet of each single cell in the sub-pile 1 connected to it, and with the help of O-rings or sealant, ensure that the electrolyte in each liquid channel 33 can be sealed and evenly distributed into each single cell, ensuring the electrochemical reaction efficiency of each single cell, thereby improving the overall electrochemical reaction efficiency of each sub-pile 1.

[0048] As can be seen, this application achieves high efficiency and independence in electrolyte distribution through the innovative design of two or more parallel sub-pile 1 and self-diverting liquid guide pipe 3. It ensures that the independent liquid channels 33 formed by the multiple concentric pipes 31 of the self-diverting liquid guide pipe 3 are connected to each sub-pile 1 respectively, and the electrolyte flow in each sub-pile 1 does not interfere with each other. This greatly reduces the flow resistance of the electrolyte in each liquid channel 33, reduces the potential difference, reduces the polarization of the battery, reduces energy loss, and increases energy efficiency. At the same time, the lateral opening 34 can cover the liquid inlet or outlet of each single cell in the sub-pile 1 connected to it, thereby simultaneously supplying or discharging liquid to multiple single cells and avoiding the situation where the electrolyte flow rate in each single cell is inconsistent due to the series connection of multiple single cells.

[0049] In some embodiments, each liquid channel 33 is open at one end for liquid inlet or outlet; the other end is closed, so that the electrolyte can only be discharged or flow in through the lateral opening 34. Furthermore, the open ends 32 of multiple liquid channels 33 are located on the same side, please refer to... Figure 3 Furthermore, the opening ends 32 are located at the same transverse cross-section, which ensures that the electrolyte of all sub-pile 1 can enter their respective corresponding liquid channels 33 simultaneously and uniformly, avoiding uneven flow caused by different inlet positions, thereby ensuring the consistency of the pile performance. The lateral opening 34 is located between the opening end 32 and the closed end 35 of the liquid channel 33, which is connected to it, so that the electrolyte in the liquid channel 33 can flow out fully from the lateral opening 34.

[0050] Please refer to Figure 3 and Figure 4 Along the axial direction from the open end 32 to the closed end 35 of the liquid channel 33, the lateral openings 34 are sequentially connected to the outermost to the innermost liquid channels 33 in the order of arrangement. This embodiment takes four liquid channels 33 as an example for further description, and there are also four corresponding lateral openings 34. The outermost liquid channel 33 is connected to the first lateral opening 34 near its open end 32; the next outermost liquid channel 33 is connected to the second lateral opening 34 near its open end 32; the next innermost liquid channel 33 is connected to the third lateral opening 34 near its open end 32; and the innermost liquid channel 33 is connected to the lateral opening 34 farthest from its open end 32.

[0051] It is foreseeable that if the lateral opening 34 corresponding to the innermost liquid channel 33 were located near the opening end 32, the lateral opening 34 would have to "pass through" the wall of the outer pipe 31, resulting in a very complex structure and a high risk of leakage. Now, however, the lateral opening 34 of the inner liquid channel 33 is arranged axially away from the opening end 32, perfectly avoiding the outer channel and achieving true physical isolation. The structure is simple and reliable.

[0052] Furthermore, through the above configuration, regardless of how many sub-pile 1s need to be stacked, it is only necessary to arrange the lateral openings 34 axially backward and the liquid channels 33 radially inward, thus completely breaking the traditional limitations on the number of single or dual pile stacks.

[0053] In some embodiments, in any liquid channel 33 and the lateral opening 34 connected thereto, the closed end 35 of the liquid channel 33 corresponds to the side of the lateral opening 34 away from the open end 32 of the liquid channel 33, so that after the electrolyte enters from the open end 32 of the liquid channel 33, it first fills the entire liquid channel 33, and then flows out from the corresponding lateral opening 34, thus preventing uneven distribution caused by the nearby diversion at the open end 32.

[0054] Please refer to Figure 5 Longitudinal support columns 37 are arranged between adjacent pipes 31, and multiple support columns 37 are evenly distributed around the circumference of the pipes 31. The length and width of the support columns 37 are not specifically limited, as long as they can stably support the diameter of adjacent pipes 31 without affecting the flow rate of each liquid channel 33.

[0055] In addition, the flow cross-sectional area of ​​each liquid channel 33 is the same, so that when the electrolyte enters each liquid channel 33 at the opening end 32 of the liquid channel 33, it can be evenly distributed into each liquid channel 33, ensuring that the flow rate of electrolyte entering each sub-pile 1 is equal, and ensuring that there is no electrolyte concentration polarization in the electrochemical reaction.

[0056] It should be noted that each pipe 31 can adopt a variable diameter design, meaning that the diameter of each pipe 31 can be selected differently according to actual needs, thereby changing the flow cross-sectional area of ​​the liquid channel 33, so that the self-diverting liquid guide pipe 3 can be adapted to the stack structure with different electrolyte requirements. On this basis, it should be ensured that the flow cross-sectional area of ​​each liquid channel 33 is the same.

[0057] The flow battery stack of this application also includes an end plate 2, please refer to... Figure 1 The end plates 2 are located on both sides of the multiple sub-fuel stacks 1, thereby locking the multiple sub-fuel stacks 1 together by fasteners (e.g., screw bolts) on the two end plates 2.

[0058] The end plate 2 is provided with a through hole 21 corresponding to the liquid inlet. The self-diverting liquid guide tube 3 is inserted into the liquid interface 11 through the through hole 21. A sealing joint 4 is fixedly provided in the through hole 21. One end of the sealing joint 4 is sealed and connected to the opening end 32 of the liquid channel 33, and the other end is connected to the electrolyte, so that the electrolyte can flow into each liquid channel 33 in a sealed manner.

[0059] Furthermore, the sealing joint 4 includes a hollow flow channel 41 and an annular groove 42 arranged on the outer periphery of the hollow flow channel 41, please refer to Figure 9 The outermost pipe 31 includes an integrally formed outer pipe 311 and an inner pipe 312. Please refer to... Figure 5 The outer tube 311 extends axially and extends beyond the opening end 32 of the liquid channel 33, with the extended portion inserted into the annular groove 42. The outer tube 311 and the annular groove 42 are interference-fitted, and the outer wall and / or inner wall of the outer tube 311 are provided with a sealing ring 36 that seals with the annular groove 42, thereby achieving multi-layer sealing between the self-distributing liquid guide tube and the sealing joint 4, eliminating the risk of leakage.

[0060] In addition, the inner diameter of the hollow flow channel 41 is the same as the inner diameter of the inner tube 312, which allows the electrolyte to smoothly transition between the hollow flow channel 41 and the opening end 32 of the liquid channel 33, making the electrolyte pressure more stable and ensuring that the electrolyte can be evenly distributed in each liquid channel 33.

[0061] Please refer to Figure 6 The liquid interface 11 includes a positive electrode inlet 113, a negative electrode inlet 112, a positive electrode outlet 111, and a negative electrode outlet 114 located at the four corners of the sub-pile 1. Correspondingly, the end plate 2 is provided with through holes 21 corresponding to the above four inlets and outlets. Multiple self-diverting liquid guide tubes 3 are inserted into the corresponding inlets or outlets through the through holes 21 on one side of the end plate 2, and then inserted into the insulating plate on the other side.

[0062] Furthermore, the positive electrode inlet 113 and the positive electrode outlet 111 are diagonally distributed, and correspondingly, the negative electrode inlet 112 and the negative electrode outlet 114 are also diagonally distributed. Self-diverting liquid guide tubes 3 are inserted into the positive electrode inlet 113, the positive electrode outlet 111, the negative electrode inlet 112, and the negative electrode outlet 114, so that the positive and negative electrode electrolytes form a "U"-shaped flow path in the entire stack structure.

[0063] The liquid inlets 11 on multiple sub-pile 1s correspond to each other, and multiple self-diverting liquid guide tubes 3 are inserted into the corresponding liquid inlets 11 through different through holes 21. Different lateral openings 34 on the same self-diverting liquid guide tube 3 are connected to different sub-pile 1s. For example, corresponding to the positive electrode inlet 113 of each sub-pile 1, the self-diverting liquid guide tube 3 can sequentially pass through multiple positive electrode inlets 113, and each lateral opening 34 can be connected to the positive electrode inlet 113 of each sub-pile 1, so that the electrolyte, after being diverted by the self-diverting liquid guide tube 3, enters the positive electrode inlet 113 of each sub-pile 1. Similarly, the positive electrode outlet 111, negative electrode inlet 112, and negative electrode outlet 114 are also configured in this way.

[0064] In some embodiments, the self-diverting liquid guide tube 3 can be made of one or more of the following materials: PP, PE, PVC, UPVC, ABS, etc., and processed by an integral molding process. The self-diverting liquid guide tube 3 can be fixed inside the fuel cell stack by processes such as glue, hot melt film, laser welding, etc. Except for the side opening 34, all other parts of the outermost pipe 31 can be fixedly bonded to the inside of the fuel cell stack to ensure the product's airtightness.

[0065] In addition, multiple sub-pile stacks 1 are connected in series, and current collectors 5 are led out from the outermost positive and negative terminals of the multiple sub-pile stacks 1. Please refer to [reference needed]. Figure 7 and Figure 8 An insulating layer 6 is provided between the end plate 2 and the current collector 5 to ensure the overall performance of the flow battery stack.

[0066] It should be noted that, compared with the traditional fuel cell stack structure, this application, through the built-in self-diverting liquid guide tube 3, enables the fuel cell stack structure of this application to only require two plate ends, two insulating plates and two current collectors 5, thereby reducing the amount of materials used and lowering the cost of the fuel cell stack.

[0067] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0068] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A flow battery stack, characterized by, The self-flowing liquid guide pipe (3) comprises two or more sub-stacks (1) arranged in parallel and a liquid interface (11) inserted into a plurality of the sub-stacks (1), and the self-flowing liquid guide pipe (3) comprises a plurality of concentrically arranged pipes (31), the internal space of the innermost pipe (31) and the annular space between adjacent pipes (31) together form a liquid passage (33) consistent with the number of the sub-stacks (1) and independent of each other; A plurality of lateral openings (34) are arranged on the outermost pipe (31) in the axial direction, and the lateral opening (34) is in sealed communication with the liquid interface (11) of one of the sub-stacks (1) on the radially outward side, the lateral opening (34) extends radially inward and is in communication with one of the liquid passages (33), and the lateral opening (34) covers the liquid inlet or outlet of each single cell in the sub-stack (1) connected thereto; The liquid passage (33) is open at one end and closed at the other end; The open ends (32) of a plurality of the liquid passages (33) are located on the same side and at the same cross section; The lateral opening (34) is located between the open end (32) and the closed end (35) of the liquid passage (33) connected thereto; In the axial direction from the open end (32) to the closed end (35) of the liquid passage (33), the lateral opening (34) is sequentially connected to the liquid passages (33) from the outermost to the innermost in the arrangement order.

2. The flow battery stack of claim 1, wherein, In any of the liquid passages (33) and the lateral opening (34) connected thereto, the closed end (35) of the liquid passage (33) corresponds to the side of the lateral opening (34) away from the open end (32) of the liquid passage (33).

3. The flow battery stack of claim 1, wherein, A plurality of support columns (37) are arranged between adjacent pipes (31), and a plurality of support columns (37) are uniformly distributed along the circumferential direction of the pipe (31).

4. The flow battery stack of claim 1, wherein, The flow area of each liquid passage (33) is the same, and the size of each lateral opening (34) is the same.

5. The flow battery stack of claim 1, wherein, It also includes an end plate (2) located on both sides of a plurality of the sub-stacks (1) to clamp a plurality of the sub-stacks (1); The end plate (2) is provided with a through hole (21) corresponding to the liquid interface (11), and the self-flowing liquid guide pipe (3) is inserted into the liquid interface (11) through the through hole (21).

6. The flow battery stack of claim 5, wherein, A sealing joint (4) is fixedly arranged in the through hole (21), one end of the sealing joint (4) is in sealed communication with the open end (32) of the liquid passage (33), and the other end of the sealing joint (4) is in contact with the electrolyte.

7. The flow battery stack of claim 6, wherein, The sealing joint (4) comprises a hollow flow channel (41) and an annular groove (42) arranged on the outer periphery of the hollow flow channel (41); The outermost pipe (31) comprises an outer pipe (311) and an inner pipe (312) integrally formed, the outer pipe (311) extends in the axial direction and beyond the open end (32) of the liquid passage (33), and the excess part is inserted into the annular groove (42); The outer tube (311) is in interference fit with the annular groove (42), and the outer wall and / or the inner wall of the outer tube (311) is provided with a sealing ring (36) in sealing fit with the annular groove (42), and the inner diameter of the hollow flow channel (41) is consistent with the inner diameter of the inner tube (312).

8. The flow battery stack of claim 5, wherein, The liquid interface (11) comprises positive electrode inlets (113), negative electrode inlets (112), positive electrode outlets (111) and negative electrode outlets (114) arranged at four corners of the sub-stacks (1), and the positive electrode inlets (113) and the positive electrode outlets (111) are diagonally distributed. The liquid interfaces (11) on the plurality of sub-stacks (1) correspond to each other, the plurality of self-flowing liquid guide pipes (3) are respectively inserted into the corresponding liquid interfaces (11) through different through holes (21), and different lateral openings (34) on the same self-flowing liquid guide pipe (3) are respectively in communication with different sub-stacks (1).

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