Modularized flow cell stack and production process thereof

Abstract

The invention belongs to the technical field of flow cells, and discloses a modular flow cell stack and a production process thereof. The flow cell stack comprises a lower end plate assembly, a lower insulation board, a negative collector plate, a first cell structure, n single cell structures, a separation single cell structure, m single cell structures, a tail cell structure, a positive collector plate, an upper insulation board and an upper end plate assembly which are stacked from bottom to top, n is a positive integer greater than 2, and m is equal to n-2. The single battery structures of the flow battery are the same repeated modules, the repeated modules are stacked section by section at the assembly station, the assembly difficulty is reduced by the repeated module assembly, and the assembly efficiency is improved. The assembly of the flow cell stack has a high requirement on precision, and each single cell structure is independently produced and is subjected to quality control, so that the consistency of the module can be improved, and the performance unification of adjacent cell sections is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of flow batteries, and particularly relates to a modular flow battery stack and its production process. Background Art

[0002] The main components of a flow battery are a flow field frame, a bipolar plate, a membrane, an electrode, and a gasket. In the initial stage of design verification, the flow field frame is mostly produced by machining or injection molding. The bipolar plate is produced by molding or extrusion. Carbon felt, carbon paper, or carbon cloth electrodes are used inside the battery. The ion exchange membrane is cut into shape in a standardized manner. Sealing gaskets produced by vulcanization machines, injection molding, or even dispensing and curing are installed on the flow field frame to seal the flowing liquid inside the battery section. Each component is produced independently, and at the stacking station of the battery stack, or directly on the press table, manual or mechanized assembly of each component is carried out one by one. This method requires a lot of complex assembly operations in a limited space, is prone to assembly errors, and reduces the yield. Summary of the Invention

[0003] In view of the above problems, the present invention provides a modular flow battery stack and its production process, and adopts the following technical solutions:

[0004] A modular flow battery stack includes a lower end plate assembly, a lower heat insulation plate, a negative current collector plate, a first battery structure, n single battery structures, a partition single battery structure, m single battery structures, a tail battery structure, a positive current collector plate, an upper heat insulation plate, and an upper end plate assembly stacked from bottom to top, where n is a positive integer greater than 2, and m = n - 2;

[0005] Among them, the single battery structure includes a battery component C1, a membrane A, and a negative electrode A. The battery component C1 includes a bipolar plate A, a positive electrode A, a first cover plate A, a second cover plate A, and a plate frame A;

[0006] One of the first cover plates A and two of the second cover plates A are arranged on the upper end surface of the bipolar plate A. A first cavity is arranged in the middle position of the first cover plate A, and the positive electrode A is located in the first cavity. Two square notches are arranged diagonally on the first cover plate A, and one of the second cover plates A is arranged at each square notch;

[0007] The plate frame A is arranged on the lower end surface of the bipolar plate A. A second cavity is arranged in the middle position of the plate frame A, and the membrane A and the negative electrode A are stacked from bottom to top in the second cavity.

[0008] Further, four first shared channels are provided at the four corners of the bipolar plate A, two second shared channels are provided along the diagonal of the first cover plate A, and one second shared channel is provided on each of the second cover plates A. The four second shared channels are arranged in one-to-one correspondence with the four first shared channels;

[0009] The plate frame A is provided with four third shared channels corresponding to the first shared channels and the second shared channels at the four corners.

[0010] Further, a positive electrolyte flow channel is provided on the first end face of the plate frame A in contact with the bipolar plate A. A positive electrolyte flow channel, a negative electrolyte flow channel and a turning hole are provided on the second end face of the plate frame A opposite to the first end face. The negative electrolyte flows from the negative electrolyte flow channel on the second end face of the plate frame A into the first end face of the plate frame A through the turning hole, and the positive electrolyte flows on the second end face of the plate frame A;

[0011] An electrolyte flow channel is provided on the first end face of the first cover plate in contact with the bipolar plate A. A number of flow equalizing bosses with the same structure and distributed in a tooth shape are provided in both the negative electrolyte flow channel on the first end face of the plate frame A and the electrolyte flow channel on the first end face of the first cover plate A.

[0012] Further, an assembly auxiliary groove is provided at the short side position of the first cavity on the first end face of the first cover plate A. Cover plate positioning bosses and a number of welding grooves are provided on the second end faces of the first cover plate A and the second cover plate A opposite to the first end face. Four assembly auxiliary grooves are symmetrically provided at the short side position of the first cavity on the first end face of the first cover plate A.

[0013] Further, laser welding ribs and plate frame positioning bosses are provided on the first end face of the plate frame A, and an outer seal laser welding groove, a cover plate positioning groove, a first seal groove, a glue reduction groove and a plate frame positioning groove are provided on the second end face of the plate frame A;

[0014] Among them, the laser welding ribs are arranged around the first end face of the plate frame A and are located outside the four third shared channels; the plate frame positioning bosses are provided on both sides of the first end face of the plate frame A and are located outside the laser welding ribs. The outer seal laser welding groove is arranged around the second end face of the plate frame A and is located outside the first seal groove. The cover plate positioning groove is arranged in a matching manner with the cover plate positioning boss. The first seal groove is arranged along the positive electrolyte flow channel, the negative electrolyte flow channel and the second cavity on the second end face of the plate frame A. The glue reduction groove is provided at the non-sealed position of the second end face of the plate frame A, and the plate frame positioning groove is provided outside the outer seal laser welding groove.

[0015] Further, the first - stage battery structure includes a frame B, a negative electrode B, and a membrane B;

[0016] Among them, the frame B has the same structure as the frame A. The negative electrode B and the membrane B are stacked from bottom to top in the second cavity of the frame B. Each third shared channel on the first end - face of the frame B cooperates with four first through - holes on the negative current - collecting plate and is flush with the outer end - face of the negative current - collecting plate.

[0017] Further, the last - stage battery structure includes a membrane C, a first cover plate B, a second cover plate B, and a positive electrode B;

[0018] Among them, the first cover plate B has the same structure as the first cover plate A, the second cover plate B has the same structure as the second cover plate A. The membrane C and the positive electrode B are stacked from bottom to top in the first cavity of the first cover plate B. The second shared channel between the second cover plate B and the first cover plate B cooperates with four second through - holes on the positive current - collecting plate and is flush with the outer end - face of the positive current - collecting plate.

[0019] Further, the separated single - cell structure includes a battery assembly C2, a membrane D, and a negative electrode C;

[0020] Among them, the battery assembly C2 includes a bipolar plate B, a positive electrode C, a first plug cover plate, a second plug cover plate, a frame C, and four plugs;

[0021] The bipolar plate B has the same structure as the bipolar plate A, the frame C has the same structure as the frame A. One first plug cover plate and two second plug cover plates are arranged on the upper end - face of the bipolar plate B. A third cavity is arranged in the middle position of the first plug cover plate. The positive electrode C is located in the third cavity. Two square notches are arranged diagonally on the first plug cover plate, and one second plug cover plate is arranged at each square notch;

[0022] The frame C is arranged on the lower end - face of the bipolar plate B. A fourth cavity is arranged in the middle position of the frame C. The membrane D and the negative electrode C are stacked from bottom to top in the fourth cavity;

[0023] The four plugs are respectively used to seal the four liquid - flow inlets and outlets of the battery assembly C2. The four liquid - flow inlets and outlets include four first shared channels on the bipolar plate B, four second shared channels on one first plug cover plate and two second plug cover plates, and four third shared channels on the frame C.

[0024] Further, two first copper taps are provided at the lower end of the negative current collector plate. Two first through slots are provided on the lower heat insulation plate, the lower end plate, and the first reinforcing sheet metal part. The two first copper taps pass through the first through slots on the lower heat insulation plate, the lower end plate, and the first reinforcing sheet metal part. First liquid flow ports communicating with the four third shared channels of the plate frame are provided at the four corners of the lower heat insulation plate.

[0025] Four third through holes corresponding to the four first liquid flow ports are provided at the four corners of the lower end plate and the first reinforcing sheet metal part. A second sealing groove is provided on the upper end face of the negative current collector plate, and a sealing gasket is provided in the second sealing groove.

[0026] Further, two second copper taps are provided at the upper end of the positive current collector plate. Two second through slots are provided on the upper heat insulation plate, the upper end plate, and the second reinforcing sheet metal part. The two second copper taps pass through the second through slots on the upper heat insulation plate, the upper end plate, and the second reinforcing sheet metal part. Second liquid flow ports communicating with the four second shared channels on the first cover plate and the second cover plate are provided at the four corners of the upper heat insulation plate.

[0027] Fourth through holes corresponding to the four second liquid flow ports are provided at the four corners of the upper end plate and the second reinforcing sheet metal part.

[0028] Further, the modular flow battery stack further includes four bending parts, wherein the four bending parts are respectively connected to the two first copper taps and the two second copper taps.

[0029] Further, the first cover plate A, the first cover plate B, the second cover plate A, the second cover plate B, the first plug cover plate, and the second plug cover plate are all light-transmissive, and the bipolar plates A and B are made of light-absorbing materials.

[0030] Further, a packaging film structure is further included. The packaging film structure surrounds the periphery of the negative current collector plate, the first battery structure, n single battery structures, the separated single battery structure, m single battery structures, the last battery structure, and the positive current collector plate, and is located between the lower heat insulation plate and the upper heat insulation plate.

[0031] The present invention also provides a production process for the modular flow battery stack described above, including the following steps:

[0032] Fix the positive electrode in the middle position of the bipolar plate by hot pressing to obtain component A;

[0033] Fix one first cover plate and two second cover plates to the upper end face of the bipolar plate in component A by laser welding to obtain component B1; fix one first plug cover plate and two second plug cover plates to the upper end face of the bipolar plate in component A by laser welding to obtain component B2;

[0034] The plate frame and component B1 are fixedly connected by laser welding to obtain battery component C1; the plate frame and component B2 are fixedly connected by laser welding to obtain battery component C2 for separating the single cell structure.

[0035] The lower end plate assembly, lower heat insulation plate, negative current collector plate, first cell structure, n single cell structures, separated single cell structure, m single cell structures, last cell structure, positive current collector plate, upper heat insulation plate, and upper end plate assembly are stacked in sequence from bottom to top to obtain a flow battery stack.

[0036] Furthermore, it also includes producing the plate frame, specifically as follows:

[0037] The plate frame body is produced by the first injection molding process, and the gasket in the first sealing groove of the plate frame is produced by the second injection molding process, or the gasket produced by molding or dispensing is pasted in the first sealing groove.

[0038] Furthermore, stacking the lower end plate assembly, lower heat insulation plate, negative current collector plate, first cell structure, n single cell structures, separated single cell structure, m single cell structures, last cell structure, positive current collector plate, upper heat insulation plate, and upper end plate assembly in sequence from bottom to top to obtain a flow battery stack includes the following steps:

[0039] Stack the first reinforcing sheet metal part, lower end plate, lower heat insulation plate, and negative current collector plate, install gaskets in the second sealing groove at the upper end of the negative current collector plate, and install gaskets in the sealing groove of the first liquid flow port of the lower heat insulation plate. Among them, the first reinforcing sheet metal part, lower end plate, and lower heat insulation plate are connected by bolts; the bending part, lower current collector plate, and lower end plate are connected by bolts; the first reinforcing sheet metal part, lower end plate, lower heat insulation plate, and negative current collector plate are connected by the bending part and bolts;

[0040] Stack the plate frame of the first cell structure above the negative current collector plate, and install the negative electrode and membrane from bottom to top in the first cavity of the plate frame of the first cell structure;

[0041] Stack n single cell structures, separated single cell structure, and m single cell structures in sequence above the plate frame;

[0042] Install the membrane of the last cell structure, two second covers, one first cover, and positive electrode on the top single cell structure in sequence;

[0043] Install the positive current collector plate, upper heat insulation plate, bending part, upper end plate, and second reinforcing sheet metal part in sequence above the last cell structure; among them, the second reinforcing sheet metal part, upper end plate, and upper heat insulation plate are connected by bolts; the bending part, upper current collector plate, and upper end plate are connected by bolts; the second reinforcing sheet metal part, upper end plate, upper heat insulation plate, and positive current collector plate are connected by the bending part and bolts;

[0044] After the assembly is completed, remove the four bent parts for recycling and use them for the next assembly.

[0045] Furthermore, the plate frame and component B1 are fixedly connected by laser welding to obtain battery component C1; the plate frame and component B2 are fixedly connected by laser welding to obtain battery component C2 for separating single battery structures, including the following steps:

[0046] The tabletop of the laser welding machine is embedded with component B1, and the four third shared channels of the plate frame are welded to the four second shared channels on one first cover plate and two second cover plates to obtain a semi-finished product of battery component C1.

[0047] The tabletop of the laser welding machine is embedded with component B2, and the four third shared channels of the plate frame are welded to the four second shared channels on one first plug cover plate and two second plug cover plates to obtain a semi-finished product of battery component C2.

[0048] Place the semi-finished products of battery component C1 and battery component C2 on the tabletop of the laser welding machine, and use a light-transmitting plate or a glass plate to press the laser welding ribs and the outer ring of the bipolar plate on the first end face of the plate frame. Melt the laser welding ribs through the laser welding machine to weld and fix the plate frame to the outer ring of the bipolar plate, obtaining the finished products of battery component C1 and battery component C2.

[0049] Furthermore, it also includes the following steps:

[0050] The flow battery stack is externally encapsulated by a packaging film structure.

[0051] Advantages of the present invention:

[0052] 1. The single battery structure of the flow battery of the present invention is the same repeating module, and is stacked section by section at the assembly station. The assembly of the repeating module reduces the assembly difficulty and improves the assembly efficiency. The assembly of the flow battery stack has high requirements for precision. Each single battery structure is produced separately and subjected to quality control, which can improve the consistency of the modules and ensure the uniform performance of adjacent battery sections.

[0053] 2. The production process of the modular flow battery stack provided by the present invention uses processes and technologies such as laser welding, injection molding, hot pressing plate, and external encapsulation during the production process, realizing the modular production and assembly of the battery stack. The prefabricated parts are produced by combining laser welding, resistance heating plate molding, single-color injection molding or two-color injection molding processes, improving the yield rate of battery units.

[0054] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification and the drawings. Description of the Drawings

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0056] Figure 1 Shows an isometric view of a modular flow battery stack according to an embodiment of the present invention;

[0057] Figure 2 Shows an exploded view of a modular flow battery stack according to an embodiment of the present invention;

[0058] Figure 3 Shows an exploded view of a single cell structure according to an embodiment of the present invention;

[0059] Figure 4 Shows an exploded view of assembly B1 of the first cover plate A, the second cover plate A and the bipolar plate A according to an embodiment of the present invention;

[0060] Figure 5 Shows a schematic diagram of the first end face structure of the first cover plate A and the second cover plate A according to an embodiment of the present invention;

[0061] Figure 6 Shows a schematic diagram of the second end face structure of the first cover plate A and the second cover plate A according to an embodiment of the present invention;

[0062] Figure 7 Shows a schematic diagram of the structure of the first end face of the plate frame according to an embodiment of the present invention;

[0063] Figure 8 Shows a schematic diagram of the structure of the second end face of the plate frame according to an embodiment of the present invention;

[0064] Figure 9 Shows according to Figure 8 A partial enlarged schematic view at G in;

[0065] Figure 10 Shows an exploded view of the structure of the first cell according to an embodiment of the present invention;

[0066] Figure 11 Shows an exploded view of the structure of the last cell according to an embodiment of the present invention;

[0067] Figure 12 Shows an exploded view of the structure of the partitioned single cell according to an embodiment of the present invention;

[0068] Figure 13Shows an exploded view of the assembly B2 of the first plug cover plate, the second plug cover plate and the bipolar plate B according to an embodiment of the present invention;

[0069] Figure 14 Shows a schematic structural diagram of the first end face of the first plug cover plate and the second plug cover plate according to an embodiment of the present invention;

[0070] Figure 15 Shows a schematic structural diagram of the second end face of the first plug cover plate A and the second plug cover plate A according to an embodiment of the present invention;

[0071] Figure 16 Shows a schematic structural diagram of the negative current collector plate according to an embodiment of the present invention;

[0072] Figure 17 Shows a schematic structural diagram of the positive current collector plate according to an embodiment of the present invention;

[0073] Figure 18 Shows a schematic structural diagram of the encapsulation film structure according to an embodiment of the present invention;

[0074] Figure 19 Shows a schematic installation diagram of the bipolar plate A and the positive electrode A according to an embodiment of the present invention;

[0075] Figure 20 Shows a schematic diagram of the production process flow of the battery assembly according to an embodiment of the present invention;

[0076] Figure 21 Shows a schematic diagram of the production process flow of the negative current collector plate and the positive current collector plate according to an embodiment of the present invention.

[0077] In the figure: 1. First reinforcing sheet metal part; 2. Lower end plate; 3. Lower heat insulation plate; 4. Negative current collector plate; 5. First battery cell structure; 6. Single battery cell structure; 7. Separated single battery cell structure; 8. Last battery cell structure; 9. Positive current collector plate; 10. Upper heat insulation plate; 11. Upper end plate; 12. Second reinforcing sheet metal part; 13. Bipolar plate A; 14. Positive electrode A; 15. First cover plate A; 16. Second cover plate A; 17. Plate frame A; 18. Membrane A; 19. Negative electrode A; 20. First shared channel; 21. Second shared channel; 22. Third shared channel; 23. Flow equalizing boss; 24. Assembly auxiliary groove; 25. Cover plate positioning boss; 26. Welding groove; 27. Flipping hole; 28. Laser welding rib; 29. Plate frame positioning boss; 30. Outer seal laser welding groove; 31. Cover plate positioning groove; 32. First seal groove; 33. Glue reduction groove; 34. Plate frame positioning groove; 35. Plate frame B; 36. First cover plate B; 37. Second cover plate B; 38. Bipolar plate B; 39. First plug cover plate; 40. Second plug cover plate; 41. Plate frame C; 42. Plug; 43. First copper tap; 44. First through groove; 45. First liquid flow port; 46. Third through hole; 47. Second seal groove; 48. Second copper tap; 49. Second through groove; 50. Second liquid flow port; 51. Fourth through hole; 52. Bending part; 53. Encapsulation film structure; 54. Outer encapsulation film; 55. Heat fusion film. Detailed implementation manners

[0078] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0079] It should be noted that the terms "first", "second", etc. in this application are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to implement the embodiments of the present application described herein. In this application, the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. are based on the orientation or positional relationships shown in the drawings.

[0080] The present invention provides a modular flow battery stack and its production process. The parts of the flow battery stack are made into components, reducing the types of parts. Each component is produced at an independent station and assembled at the assembly station, greatly reducing the steps of the assembly operation. The present invention also makes a single battery of the flow battery stack into a module, further accelerating the assembly rate and ensuring the product quality.

[0081] As Figure 1 and Figure 2 shown, a modular flow battery stack includes a lower end plate assembly, a lower heat insulation plate 3, a negative current collector plate 4, a first battery structure 5, n single battery structures 6, a separator for single battery structures 7, m single battery structures 6, a last battery structure 8, a positive current collector plate 9, an upper heat insulation plate 10, and an upper end plate 11 assembly, which are stacked from bottom to top. n is a positive integer greater than 2, and m = n - 2.

[0082] The battery structure of the present invention is an independent module. Each component used before module combination is independently produced, and quality control is carried out separately for each component. Repeated module assembly reduces the assembly difficulty and improves the assembly efficiency.

[0083] For example, as Figure 1 and Figure 2 shown, the lower end plate assembly includes a first reinforcing sheet metal part 1 and a lower end plate 2 stacked from bottom to top, and the upper end plate 11 assembly includes an upper end plate 11 and a second reinforcing sheet metal part 12 stacked from bottom to top.

[0084] For example, as Figure 3 and Figure 4 shown, the single battery structure 6 includes a battery component C1, a membrane A18, and a negative electrode A19. The battery component C1 includes a bipolar plate A13, a positive electrode A14, a first cover plate A15, a second cover plate A16, and a frame A17. One first cover plate A15 and two second cover plates A16 are arranged on the upper end face of the bipolar plate A13. Among them, four first shared channels 20 are arranged at the four corners of the bipolar plate.

[0085] A first cavity is arranged at the middle position of the first cover plate A15, and the positive electrode A14 is located in the first cavity. Two square notches are arranged diagonally on the first cover plate A15, and one second cover plate A16 is arranged at each square notch.

[0086] The frame A17 is arranged on the lower end face of the bipolar plate A13. A second cavity is arranged at the middle position of the frame A17, and the membrane A18 and the negative electrode A19 are stacked from bottom to top in the second cavity.

[0087] For example, as Figure 3 and 4As shown, four first shared channels 20 are provided at the four corners of the bipolar plate A13, two second shared channels 21 are arranged diagonally on the first cover plate A15, and one second shared channel 21 is provided on each second cover plate A16. The four second shared channels 21 are arranged in one-to-one correspondence with the four first shared channels 20. The plate frame A17 is provided with four third shared channels 22 corresponding to the first shared channels 20 and the second shared channels 21 at the four corners.

[0088] As Figure 5 shown, an electrolyte flow channel is provided on the first end face of the first cover plate A15 in contact with the bipolar plate A13. As Figure 3 and Figure 5 shown, a number of flow equalizing bosses 23 with the same structure and distributed in a toothed shape are provided in both the negative electrolyte flow channel on the first end face of the plate frame A17 and the electrolyte flow channel on the first end face of the first cover plate A15, so that the electrolyte can flow evenly through the electrode. In addition, as Figure 5 shown, four assembly auxiliary grooves 24 are provided at the short side positions of the first cavity on the first end face of the first cover plate A15.

[0089] For example, as Figure 6 shown, cover plate positioning bosses 25 are provided on both the second end faces of the first cover plate A15 and the second cover plate A16 opposite to the first end face. The first cover plate A15 is provided with a number of welding grooves 26 on the second end face, and the second cover plate A16 is provided with a number of welding grooves 26 on the second end face.

[0090] For example, the first cover plate A15 includes a first square part, a second square part and a third square part. The second square part and the third square part are arranged in parallel on one side of the two long sides of the first square part respectively. The outer side of the second square part is flush with one short side of the first square part, and the outer side of the third square is flush with the other short side of the first square part. The first cavity is arranged in the middle position of the first square part.

[0091] For example, as Figure 4 、 Figure 5 and Figure 6 shown, a total of 6 rectangular welding grooves 26 are provided on the two short sides of the first end face of the first square part in contact with the bipolar plate A13. The second cover plate A16, the second square part and the third square part are each provided with 3 rectangular welding grooves 26 on the first end face in contact with the bipolar plate A13; the second cover plate A16, the second square part and the third square part are each provided with 2 cover plate positioning bosses 25 on the second end face opposite to the first end face. The debonding design of the cover plate positioning bosses 25 ensures uniform wall thickness, facilitates the fluidity during the injection molding process, and the flatness of the injected material. The debonding design of the cover plate positioning bosses 25 ensures uniform wall thickness, facilitates the fluidity during the injection molding process, and the flatness of the injected material.

[0092] For example, asFigure 7 , 8 and Figure 9 As shown in Figure 7 , 8 and Figure 9 , the first end face of the plate frame A17 in contact with the bipolar plate A13 is provided with a positive electrolyte flow channel. The second end face of the plate frame A17 opposite to the first end face is provided with a positive electrolyte flow channel, a negative electrolyte flow channel and a turning hole 27. The negative electrolyte flows from the negative electrolyte flow channel on the second end face of the plate frame A17 through the turning hole 27 into the first end face of the plate frame A17, and the positive electrolyte flows on the second end face of the plate frame A17.

[0093] The first end face of the plate frame A17 is provided with a laser welding rib 28 and a plate frame positioning boss 29. The second end face of the plate frame A17 is provided with an outer sealing laser welding groove 30, a cover plate positioning groove 31, a first sealing groove 32, a glue reducing groove 33 and a plate frame positioning groove 34.

[0094] Among them, the laser welding rib 28 surrounds the first end face of the plate frame A17 and is located outside the four third shared channels 22. The laser welding rib 28 is used to weld the plate frame and the bipolar plate into a component. The plate frame positioning boss 29 is arranged on both sides of the first end face of the plate frame A17 and is located outside the laser welding rib 28. The plate frame positioning boss 29 cooperates with the plate frame positioning groove 34 on the plate frame of the upper single cell structure 6 to realize the assembly and positioning of the battery stack section by section.

[0095] The outer sealing laser welding groove 30 surrounds the second end face of the plate frame A17 and is located outside the first sealing groove 32. The cover plate positioning groove 31 is arranged to match the cover plate positioning boss 25 for the assembly and positioning of the cover plate. The first sealing groove 32 is arranged along the positive electrolyte flow channel, the negative electrolyte flow channel and the second cavity on the second end face of the plate frame A17.

[0096] The glue reducing groove 33 is arranged at the non-sealed position of the second end face of the plate frame A17 to adjust the wall thickness evenly, avoid the shrinkage of the injection molded hard glue, and make the surface of the plate frame as flat as possible, so as to ensure no virtual welding during the laser welding process under pressure on the plate surface.

[0097] The plate frame positioning groove 34 is arranged outside the outer sealing laser welding groove 30, and the plate frame positioning groove 34 cooperates with the plate frame positioning boss 29 on the plate frame A17 of the lower single cell structure 6.

[0098] For example, as Figure 10 shown, the first cell structure 5 includes a plate frame B35, a negative electrode B and a membrane B. As Figure 11 shown, the last cell structure 8 includes a membrane C, a first cover plate B36, a second cover plate B37 and a positive electrode B.

[0099] The frame B35 has the same structure as the frame A17. The negative electrode B and the membrane B are stacked from bottom to top in the second cavity of the frame B35. Each third shared channel 22 on the first end face of the frame B35 cooperates with four first through holes on the negative current collector plate 4 and is flush with the outer end face of the negative current collector plate 4.

[0100] The first cover plate B36 has the same structure as the first cover plate A15, and the second cover plate B37 has the same structure as the second cover plate A16. The membrane C and the positive electrode B are stacked from bottom to top in the first cavity of the first cover plate B36. The second shared channel 21 of the second cover plate B37 and the first cover plate B36 cooperates with four second through holes on the positive current collector plate 9 and is flush with the outer end face of the positive current collector plate 9.

[0101] For example, as Figure 12 shown, the separated single cell structure 7 includes the battery assembly C2, the membrane D, and the negative electrode C; wherein, the battery assembly C2 includes the bipolar plate B38, the positive electrode C, the first plug cover plate 39, the second plug cover plate 40, the frame C41, and four plugs 42.

[0102] The bipolar plate B38 has the same structure as the bipolar plate A13, and the frame C41 has the same structure as the frame A17. As Figure 13 shown, one first plug cover plate 39 and two second plug cover plates 40 are arranged on the upper end face of the bipolar plate B38. A third cavity is arranged in the middle position of the first plug cover plate 39, and the positive electrode C is located in the third cavity. Two square notches are arranged diagonally on the first plug cover plate 39, and one second plug cover plate 40 is arranged at each square notch.

[0103] As Figure 14 and Figure 15 shown, the first plug cover plate 39 has the same structure as the first cover plate A15 and the first cover plate B36, and the second plug cover plate 40 has the same structure as the second cover plate A16 and the second cover plate B37.

[0104] The frame C41 is arranged on the lower end face of the bipolar plate B38. A fourth cavity is arranged in the middle position of the frame C41, and the membrane D and the negative electrode C are stacked from bottom to top in the fourth cavity.

[0105] As Figure 14 shown, the four plugs 42 are respectively used to seal the four liquid flow inlets and outlets of the battery assembly C2. The four liquid flow inlets and outlets include four first shared channels 20 on the bipolar plate B38, four second shared channels 21 on one first plug cover plate 39 and two second plug cover plates 40, and four third shared channels 22 on the frame C41.

[0106] The wall thickness of the third shared channel 22 at the four corners of the frame A17 and the frame B35 is so thin that it can transmit light, aiming to weld the second shared channel 21 of the first cover plate A15, the first cover plate B36, the second cover plate A16 and the second cover plate B37 to the third shared channel 22 of the frame to complete the sealing of the liquid inlet hole. The areas of the second shared channel 21 blocked by the material of the first plug cover plate 39 and the second plug cover plate 40 are welded to the third shared channel 22 of the frame A17 and the frame B35 to complete the sealing of the liquid inlet hole.

[0107] For example, as Figure 10 and 16 shown, two first copper taps 43 are provided at the lower end of the negative current collector plate 4. Two first through slots 44 are provided on the lower heat preservation plate 3, the lower end plate 2 and the first strengthening sheet metal part 1. The two first copper taps 43 pass through the first through slots 44 on the lower heat preservation plate 3, the lower end plate 2 and the first strengthening sheet metal part 1. First liquid flow ports 45 communicating with the four third shared channels 22 of the frame are provided at the four corners of the lower heat preservation plate 3.

[0108] Four third through holes 46 corresponding to the four first liquid flow ports 45 are provided at the four corners of the lower end plate 2 and the first strengthening sheet metal part 1. A second sealing groove 47 is provided on the upper end face of the negative current collector plate 4. A sealing gasket is provided in the second sealing groove 47. The area where the negative current collector plate 4 is in contact with the negative electrode of the first battery structure 5 is the conductive area, and a conductive material is used. Other areas are non-conductive areas, and non-conductive materials are used. The conductive area and the non-conductive area of the negative current collector plate 4 are arranged in a "hui" character layout.

[0109] For example, as Figure 11 and Figure 17 shown, two second copper taps 48 are provided at the upper end of the positive current collector plate 9. Two second through slots 49 are provided on the upper heat preservation plate 10, the upper end plate 11 and the second strengthening sheet metal part 12. The two second copper taps 48 pass through the second through slots 49 on the upper heat preservation plate 10, the upper end plate 11 and the second strengthening sheet metal part 12. Second liquid flow ports 50 communicating with the four second shared channels 21 on the first cover plate and the second cover plate are provided at the four corners of the upper heat preservation plate 10.

[0110] Fourth through holes 51 corresponding to the four second liquid flow ports 50 are provided at the four corners of the upper end plate 11 and the second strengthening sheet metal part 12. The area where the positive current collector plate 9 is in contact with the positive electrode of the last battery structure 8 is the conductive area, and a conductive material is used. Other areas are non-conductive areas, and non-conductive materials are used. The conductive area and the non-conductive area of the positive current collector plate 9 are arranged in a "hui" character layout.

[0111] For example, the first cover plate A15, the first cover plate B36, the second cover plate A16, the second cover plate B37, the first plug cover plate 39 and the second plug cover plate 40 all have light transmittance. For example, they are made of light-transmitting materials, or have light transmittance after the material thickness is thinned to a certain extent; the bipolar plates A13 and B38 are made of light-absorbing materials.

[0112] For example, as Figure 1 , Figure 2 and Figure 18 shown, the modular flow battery stack further includes four bending members 52 and a packaging film structure 53. Among them, the four bending members 52 are respectively connected to two first copper taps 43 and two second copper taps 48.

[0113] The first copper tap 43 and the second copper tap 48 of the present invention pass through the heat preservation board, the end plate and the reinforcing sheet metal and extend out of the stack body, so that the outer surface of the battery stack is flat, which is convenient for wrapping the outer packaging film, or avoiding the leakage of the electrolyte by using a casing.

[0114] The packaging film structure 53 surrounds the periphery of the negative current collector plate 4, the first battery structure 5, n single battery structures 6, the separated single battery structure 7, m single battery structures 6, the last battery structure 8, and the positive current collector plate 9, and is located between the lower heat preservation board 3 and the upper heat preservation board 10. The packaging film structure 53 includes an outer packaging film 54 and a hot melt film 55, and the hot melt film 55 is used to seal the square ring formed by the outer packaging film 54.

[0115] As Figure 19 and Figure 20 shown, the present invention also provides a production process of the above modular flow battery stack, including the following steps:

[0116] S1. Fix the positive electrode on the middle position of the bipolar plate by hot pressing to obtain Component A, specifically as follows:

[0117] Put the bipolar plate into the mold and heat it to soften, press the positive electrode and the softened bipolar plate by a press, and then cool it down by the liquid cooling pipeline built in the mold to control the deformation of the bipolar plate.

[0118] S2. Use the first injection molding process to produce the plate frame body, and use the second injection molding process to produce the gasket in the first sealing groove 32 of the plate frame. Or use the gasket produced by methods such as molding and dispensing and paste it in the first sealing groove 32. Among them, the thin-wall position of the plate frame meets a certain light transmittance, which is convenient for laser welding.

[0119] S3. Produce the first cover plate and the second cover plate with thin-wall positions that meet the light transmittance by injection molding process, or the material is essentially light-transmitting.

[0120] S4. Fix the upper end face of a first cover plate and two second cover plates to the bipolar plate in the component by laser welding to obtain Component B1, specifically as follows:

[0121] The tabletop of the laser welding machine is embedded with two second cover plates and a first cover plate. Component A is pressed on the welding grooves 26 of the two second cover plates and the welding groove 26 of the first cover plate. The laser penetrates through the two second cover plates and the first cover plate to melt the material in contact with the bipolar plate at the welding groove 26 for welding to make Component B1.

[0122] Or, position and fix the two second cover plates and the cover plate positioning bosses 25 on the first cover plate by using the positioning mold on the tabletop of the laser welding machine. Place the component on the upper surfaces of the two second cover plates and the first cover plate, and press it firmly with a glass plate for laser welding. The laser head is arranged under the tabletop for welding from bottom to top.

[0123] Fix the upper end face of a first plug cover plate 39 and two second plug cover plates 40 to the bipolar plate in the component by laser welding to obtain Component B2. The specific operation is the same as that of Component B1.

[0124] S5. Fix the plate frame to Component B1 by laser welding to obtain Battery Component C1, specifically as follows:

[0125] S51. The tabletop of the laser welding machine is embedded with Component B1. Weld the four third shared channels 22 of the plate frame to the four second shared channels 21 on a first cover plate and two second cover plates to obtain a semi-finished product of Battery Component C1.

[0126] In this step, since the positions of the four third shared channels 22 of the plate frame are thin-walled structures that are light-transmissive, a first cover plate and two second cover plates are light-transmissive plastics or plastics with light-transmissive thin-walled positions. It is necessary to select a welding head for welding light-transmissive materials or a traditional welding head to make a semi-finished product of Battery Component C1.

[0127] S52. Place the semi-finished product of the battery component on the tabletop of the laser welding machine. Use a light-transmissive plate or a glass plate to press the laser welding ribs 28 on the first end face of the plate frame and the outer ring of the bipolar plate firmly. Melt the laser welding ribs 28 through the laser welding machine to weld and fix the plate frame to the outer ring of the bipolar plate to obtain the finished battery component. The effect is like a sealing line to complete the outer seal of the battery cell. In this step, the laser welding head is a traditional welding head.

[0128] In this step, after forming the "cover plate - electrode - bipolar plate" component, two laser welding processes are carried out with the plate frame. The first welding welds the shared channel positions of the plate frame and the cover plate to seal the liquid inlet and outlet of the single battery structure 6. The second welding continues to weld the thin-walled positions of the outer periphery of the bipolar plate and the plate frame to realize the outer seal of the single battery structure 6.

[0129] S53. Fix the frame and component B2 by laser welding to obtain the battery component C2 in the same way as the method for the battery component C1.

[0130] S6. Produce the negative current collector plate 4 and the positive current collector plate 9, specifically as follows:

[0131] As Figure 21 shown, the production of the current collector plate is an integral part formed by hot pressing with a mold. The materials in the mold cavity are placed in sequence: ordinary plastic sheet, carbon-plastic bipolar plate, copper mesh, copper tap, carbon-plastic bipolar plate. Under pressure and heating conditions, the carbon-plastic bipolar plate melts and embeds into the copper mesh, and only the copper tap is exposed for conduction. A sealing groove is pressed on the upper end face of the negative current collector plate 4. The rectangular area formed by the carbon-plastic bipolar plate conducts electricity, and the uncompacted ordinary plastic material in the remaining area does not conduct electricity. The selected ordinary plastic material has a certain compatibility with the carbon-plastic bipolar plate material.

[0132] S7. Produce the lower heat insulation plate 3 and the upper heat insulation plate 10 by machining or injection molding process. The preferred injection molding process can control the processing cost of batch products. If the upper end plate 11 and the lower end plate 2 are produced from non-metallic materials, preferably select non-metallic materials that can be molded to control the processing cost of batch products. The reinforcing sheet metal is preferably produced by casting to control the processing cost of batch products.

[0133] S8. Stack the lower end plate assembly, the lower heat insulation plate 3, the negative current collector plate 4, the first battery structure 5, n single battery structures 6, the separated single battery structure 7, m single battery structures 6, the last battery structure 8, the positive current collector plate 9, the upper heat insulation plate 10, and the upper end plate 11 assembly from bottom to top to obtain the flow battery stack, specifically as follows:

[0134] S81. Stack the first reinforcing sheet metal part 1, the lower end plate 2, the lower heat insulation plate 3, and the negative current collector plate 4, and install a gasket in the second sealing groove 47 at the upper end of the negative current collector plate 4. Among them, the first reinforcing sheet metal part 1, the lower end plate 2, and the lower heat insulation plate 3 are connected into a body by bolts, and then the negative current collector plate 4 is temporarily fixed to the lower end plate 2 with a bending part in cooperation with bolts. The assembly formed by the four is convenient for hoisting and positioning.

[0135] S82. Stack the frame of the first battery structure 5 above the negative current collector plate 4, and install the negative electrode and the membrane from bottom to top in the first cavity of the frame of the first battery structure 5.

[0136] S83. Stack n single battery structures 6, the separated single battery structure 7, and m single battery structures 6 above the frame of the first battery structure 5 in sequence.

[0137] Among them, the installation process of each single battery structure 6 is as follows: install the battery component C1, the membrane, and the negative electrode in sequence.

[0138] S84. On the single cell structure 6 at the uppermost part, successively install the membrane of the end cell structure 8, two second cover plates, one first cover plate and the positive electrode.

[0139] S85. Successively install the positive current collector plate 9, the upper heat insulation plate 10, the upper end plate 11 and the second strengthening sheet metal part 12 above the end cell structure 8. Among them, the second strengthening sheet metal part 12, the upper end plate 11 and the upper heat insulation are connected into a whole by bolts. Then, the positive current collector plate 9 is temporarily fixed to the upper end plate 11 by using a bending part in cooperation with bolts. The assembly formed by the four is convenient for hoisting and positioning.

[0140] In this step, after stacking the last single cell structure 6 of the battery stack, it is necessary to press the positive current collector plate 9 and the upper heat insulation plate 10 on the top of the battery stack. Since the surface of the battery stack after stacking is uneven, the stacked body of the plate frame is loose and has low stiffness. In order to facilitate positioning and prevent misalignment. The two bending parts on the positive current collector plate 9 are temporarily fixed by bolts. After completing the battery pressing and assembly, the four bending parts 52 are disassembled and recycled for use in the next assembly.

[0141] S9. Press the flow battery stack and perform isobaric and differential pressure airtightness detection on the pressed flow battery stack.

[0142] S10. Perform external packaging on the flow battery stack through the packaging film structure 53, specifically as follows:

[0143] S101. The hot melt film 55 and the outer packaging film are prefabricated into one to obtain the packaging film structure 53;

[0144] First, hot press the interfaces at both ends of the hot melt film 55 and the outer packaging film 54 together. The temperature and pressure should not be too high, and the pressing time should not be too long. The purpose is to simply melt the hot melt film 55 and temporarily stick it to the outer packaging film 54. The outer packaging film 54 is a thin rectangular plastic cloth that can be compatible with the material of the hot melt film 55. The hot melt film 55 is used for sealing after the outer packaging film 54 winds around the flow battery stack.

[0145] S102. Wind the packaging film structure 53 around the periphery of the negative current collector plate 4, the first cell structure 5, n single cell structures 6, the partition single cell structure 7, m single cell structures 6, the end cell structure 8, and the positive current collector plate 9.

[0146] S103. Heat melt the position of the hot melt film 55 on the packaging mold structure through a hot press plate to form a seal between the outer packaging film 54, the hot melt film 55, the lower heat insulation plate 3 and the upper heat insulation plate 10, specifically as follows:

[0147] The press presses the hot pressing plate onto the position of the hot melt film 55 on the encapsulation die structure. At this time, the temperature of the hot pressing plate needs to melt the hot melt film 55, and the pressing pressure and time need to be significantly increased. However, it is necessary to ensure that the side walls of the lower heat preservation plate 3 and the upper heat preservation plate 10 are not overly melted. The material of the hot melt film 55 needs to be fused with both the outer encapsulation film 54, the lower heat preservation plate 3, and the upper heat preservation plate 10 simultaneously to achieve a better outer encapsulation effect.

[0148] In this step, external leakage is prevented by not melting the plate frame through a hot pressing method, which facilitates the secondary use of the plate frame. After the first operation error of this outer encapsulation method, the outer encapsulation film can be torn off for multiple outer encapsulations without affecting the shape and secondary use of the other parts of the battery stack.

[0149] For example, the surface of the hot pressing plate used in hot pressing needs to be covered with a lining layer that does not fuse with the outer encapsulation film and can withstand the hot pressing temperature to prevent the melted hot melt film 55 and the outer encapsulation film 54 from sticking to the surface of the hot pressing plate.

[0150] S11. On the externally encapsulated flow battery stack, apply force to the studs, springs, and torque wrenches, and release the pressure of the press.

[0151] The single-cell structure 6 of the flow battery of the present invention is the same repeating module, which is stacked one by one at the assembly station, and the production efficiency can be greatly improved. The assembly of the flow battery stack has high requirements for accuracy. Each single-cell structure 6 is produced separately and quality controlled to improve the consistency of the modules and ensure the uniform performance of adjacent battery sections.

[0152] The production process of the modular flow battery stack provided by the present invention uses processes and technologies such as laser welding, injection molding, hot pressing plates, and outer encapsulation during the generation process, realizing the modular production and assembly of the battery stack. The prefabricated parts are produced by combining laser welding, resistance heating plate molding, single-color injection molding, or two-color injection molding processes, improving the yield rate of battery units. Modular assembly improves the production efficiency of the battery stack. The hot melt film 55 cooperates with the hot pressing plate to perform film encapsulation outside the stack to avoid leakage. The processes involved in battery stack production are mature and meet the requirements of large-scale mass production.

[0153] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modular flow battery stack, characterized in that: It includes a lower end plate assembly, a lower insulation plate, a negative current collector, a first battery structure, n single battery structures, a separated single battery structure, m single battery structures, a tail battery structure, a positive current collector, an upper insulation plate, and an upper end plate assembly stacked from bottom to top, where n is a positive integer greater than 2, and m=n-2; The single cell structure includes a battery assembly C1, a membrane A and a negative electrode A, and the battery assembly C1 includes a bipolar plate A, a positive electrode A, a first cover plate A, a second cover plate A and a plate frame A; One first cover plate A and two second cover plates A are arranged on the upper end surface of the bipolar plate A, a first cavity is arranged in the middle of the first cover plate A, the positive electrode A is located in the first cavity, the first cover plate A is arranged with two square notches along the diagonal lines, and one second cover plate A is arranged at each of the square notches; The plate frame A is arranged on the lower end surface of the bipolar plate A, a second cavity is arranged in the middle of the plate frame A, and the membrane A and the negative electrode A are stacked from bottom to top in the second cavity.

2. The modular flow battery stack according to claim 1, characterized in that: Four first shared channels are arranged at the four corners of the bipolar plate A, two second shared channels are arranged along the diagonal of the first cover plate A, one second shared channel is arranged on each of the second cover plates A, and the four second shared channels are arranged in one-to-one correspondence with the four first shared channels; The plate frame A is provided with four third sharing channels corresponding to the first sharing channels and the second sharing channels at four corners.

3. The modular liquid flow battery stack according to claim 1, characterized in that: in, The plate frame A is provided with a positive electrode electrolyte flow channel on a first end face in contact with the bipolar plate A, and the plate frame A is provided with a positive electrode electrolyte flow channel, a negative electrode electrolyte flow channel and a reversing hole on a second end face opposite to the first end face, the negative electrode electrolyte flows from the negative electrode electrolyte flow channel on the second end face of the plate frame A through the reversing hole into the first end face of the plate frame A, and the positive electrode electrolyte flows on the second end face of the plate frame A; The first end surface of the first cover plate in contact with the bipolar plate A is provided with an electrolyte flow channel, and the negative electrode electrolyte flow channel of the first end surface of the plate frame A and the electrolyte flow channel of the first end surface of the first cover plate A are both provided with a plurality of flow balancing bosses with the same toothed distribution.

4. The modular liquid flow battery stack according to claim 3, characterized in that: The first end surface of the first cover plate A is provided with an assembly auxiliary groove at the short side position of the first cavity, and the first cover plate A and the second cover plate A are both provided with a cover plate positioning boss and a plurality of welding grooves on the second end surface opposite to the first end surface, and the first end surface of the first cover plate A is symmetrically provided with four assembly auxiliary grooves at the short side position of the first cavity.

5. The modular flow battery stack according to claim 4, characterized in that: The first end surface of the plate frame A is provided with laser welding ribs and a plate frame positioning boss, and the second end surface of the plate frame A is provided with an outer sealing laser welding groove, a cover plate positioning groove, a first sealing groove, a glue reduction groove and a plate frame positioning groove; Among them, the laser welding rib is arranged around the first end surface of the plate frame A and is located on the outside of the four third shared channels; the plate frame positioning boss is arranged on both sides of the first end surface of the plate frame A and is located on the outside of the laser welding rib, the external sealing laser welding groove is arranged around the second end surface of the plate frame A and is located on the outside of the first sealing groove, the cover plate positioning groove is matched with the cover plate positioning boss, the first sealing groove is arranged along the positive electrolyte flow channel, the negative electrolyte flow channel and the second cavity on the second end surface of the plate frame A, the glue reduction groove is arranged at the non-sealed position of the second end surface of the plate frame A, and the plate frame positioning groove is arranged on the outside of the external sealing laser welding groove.

6. The modular flow battery stack according to claim 1, characterized in that: The first battery structure includes a plate frame B, a negative electrode B and a membrane B; Among them, the plate frame B has the same structure as the plate frame A, the negative electrode B and the membrane B are stacked from bottom to top in the second cavity of the plate frame B, and each third shared channel on the first end surface of the plate frame B cooperates with the four first through holes on the negative current collecting plate and is flush with the outer end surface of the negative current collecting plate.

7. The modular flow battery stack according to claim 1, characterized in that: The tail cell structure includes a membrane C, a first cover plate B, a second cover plate B and a positive electrode B; Among them, the first cover plate B has the same structure as the first cover plate A, the second cover plate B has the same structure as the second cover plate A, the membrane C and the positive electrode B are stacked from bottom to top in the first cavity of the first cover plate B, and the second shared channel of the second cover plate B and the first cover plate B cooperates with the four second through holes on the positive current collecting plate and is flush with the outer end surface of the positive current collecting plate.

8. The modular flow battery stack according to claim 7, characterized in that: The separated single cell structure includes a battery component C2, a membrane D and a negative electrode C; Among them, the battery assembly C2 includes a bipolar plate B, a positive electrode C, a first plug cover plate, a second plug cover plate, a plate frame C and four plugs; The bipolar plate B has the same structure as the bipolar plate A, the plate frame C has the same structure as the plate frame A, one of the first plugging cover plates and two of the second plugging cover plates are arranged on the upper end surface of the bipolar plate B, a third cavity is arranged in the middle of the first plugging cover plate, the positive electrode C is located in the third cavity, the first plugging cover plate is provided with two square notches along the diagonal lines, and one of the second plugging cover plates is arranged at each of the square notches; The plate frame C is arranged on the lower end surface of the bipolar plate B, a fourth cavity is arranged in the middle of the plate frame C, and the membrane D and the negative electrode C are stacked from bottom to top in the fourth cavity; The four plugs are respectively used to seal the four liquid inlets and outlets of the battery assembly C2, and the four liquid inlets and outlets include four first shared channels on the bipolar plate B, four second shared channels on a first plug cover plate and two second plug cover plates, and four third shared channels on the plate frame C.

9. The modular flow battery stack according to claim 6, characterized in that: The lower end of the negative electrode current collecting plate is provided with two first copper taps, and the lower insulation plate, the lower end plate and the first reinforcing sheet metal are all provided with two first through grooves, the two first copper taps pass through the first through grooves on the lower insulation plate, the lower end plate and the first reinforcing sheet metal, and the four corners of the lower insulation plate are provided with first liquid flow ports respectively connected with the four third shared channels of the plate frame; The lower end plate and the first reinforcing sheet metal are provided with four third through holes corresponding to the four first liquid flow ports at four corners, and the upper end surface of the negative electrode current collector is provided with a second sealing groove, in which a sealing gasket is provided.

10. The modular liquid flow battery stack according to claim 7, characterized in that: The upper end of the positive electrode current collecting plate is provided with two second copper taps, the upper insulation plate, the upper end plate and the second reinforcing sheet metal are all provided with second through grooves, the two second copper taps pass through the second through grooves on the upper insulation plate, the upper end plate and the second reinforcing sheet metal, and the four corners of the upper insulation plate are provided with second liquid flow ports respectively connected with the four second shared channels on the first cover plate and the second cover plate; The upper end plate and the second reinforcing sheet metal part are provided with fourth through holes corresponding to the four second liquid flow ports at four corners.

11. The modular liquid flow battery stack according to claim 10, characterized in that: The modular liquid flow battery stack also includes four bent pieces, wherein the four bent pieces are respectively connected to the two first copper taps and the two second copper taps.

12. The modular flow battery stack according to claim 8, characterized in that: The first cover plate A, the first cover plate B, the second cover plate A, the second cover plate B, the first plugging cover plate and the second plugging cover plate are all light-transmissive, and the bipolar plate A and the bipolar plate B are made of light-absorbing material.

13. The modular liquid flow battery stack according to any one of claims 1 to 12, characterized in that: It also includes a packaging film structure, which surrounds the periphery of the negative electrode current collector, the first battery structure, n single battery structures, the separated single battery structure, m single battery structures, the tail battery structure, and the positive electrode current collector, and is located between the lower insulation plate and the upper insulation plate.

14. A process for producing a modular liquid flow battery stack according to any one of claims 1 to 13, characterized in that: The following steps are involved: Fixing the positive electrode at the middle position of the bipolar plate by hot pressing to obtain component A; A first cover plate and two second cover plates are fixedly connected to the upper end surface of the bipolar plate in the assembly A by laser welding to obtain assembly B1; a first plug cover plate and two second plug cover plates are fixedly connected to the upper end surface of the bipolar plate in the assembly A by laser welding to obtain assembly B2; The plate frame and the assembly B1 are fixedly connected by laser welding to obtain the battery assembly C1; the plate frame and the assembly B2 are fixedly connected by laser welding to obtain the battery assembly C2 with separated single cell structures; The lower end plate assembly, the lower insulation plate, the negative electrode current collecting plate, the first battery structure, the n single battery structures, the separator single battery structure, the m single battery structures, the tail battery structure, the positive electrode current collecting plate, the upper insulation plate, and the upper end plate assembly are stacked from bottom to top to obtain a liquid flow battery stack.

15. The production process of a modular flow battery stack according to claim 14, characterized in that: It also includes the production of board frames, as follows: The plate frame body is produced by the first injection molding process, and the sealing gasket in the first sealing groove of the plate frame is produced by the second injection molding process, or the sealing gasket produced by molding and dispensing is attached to the first sealing groove.

16. The production process of a modular flow battery stack according to claim 14, characterized in that: The lower end plate assembly, the lower insulation plate, the negative electrode current collector, the first battery structure, the n single battery structures, the separator single battery structure, the m single battery structures, the tail battery structure, the positive electrode current collector, the upper insulation plate, and the upper end plate assembly are stacked from bottom to top to obtain a liquid flow battery stack, including the following steps: The first reinforcing sheet metal, the lower end plate, the lower insulation plate and the negative electrode current collecting plate are stacked, and a sealing gasket is installed in the second sealing groove at the upper end of the negative electrode current collecting plate, and a sealing gasket is installed in the sealing groove of the first liquid flow port of the lower insulation plate, wherein the first reinforcing sheet metal, the lower end plate and the lower insulation plate are connected by bolts; the bending piece, the lower current collecting plate and the lower end plate are connected by bolts; the first reinforcing sheet metal, the lower end plate, the lower insulation plate and the negative electrode current collecting plate are connected by the bending piece and bolts; Stacking a plate frame of the first battery structure above the negative electrode current collector, and installing the negative electrode and the membrane in the first cavity of the plate frame of the first battery structure from bottom to top; stacking n single cell structures, a separator single cell structure and m single cell structures in sequence above the plate frame; The membrane of the tail cell structure, two second cover plates, a first cover plate and a positive electrode are sequentially installed on the uppermost single cell structure; The positive electrode current collecting plate, the upper insulation plate, the bending part, the upper end plate and the second reinforcing sheet metal are sequentially installed above the tail battery structure; wherein the second reinforcing sheet metal, the upper end plate and the upper insulation plate are connected by bolts; the bending part, the upper current collecting plate and the upper end plate are connected by bolts; the second reinforcing sheet metal, the upper end plate, the upper insulation plate and the positive electrode current collecting plate are connected by the bending part and bolts; After the assembly is completed, the four bent parts are disassembled and recycled for use in the next assembly.

17. The production process of a modular flow battery stack according to claim 14, characterized in that: The plate frame and the assembly B1 are fixedly connected by laser welding to obtain the battery assembly C1; the plate frame and the assembly B2 are fixedly connected by laser welding to obtain the battery assembly C2 with separated single battery structure, including the following steps: The table of the laser welding machine is embedded in the component B1, and the four third shared channels of the plate frame are welded with the four second shared channels on a first cover plate and two second cover plates to obtain a semi-finished product of the battery component C1. The table of the laser welding machine is embedded in the component B2, and the four third shared channels of the plate frame are welded with the four second shared channels on a first plugging cover plate and two second plugging cover plates to obtain a semi-finished product of the battery component C2; Place the semi-finished products of battery assembly C1 and battery assembly C2 on the table of a laser welding machine, use a light-transmitting plate or a glass plate to compact the laser welding ribs on the first end face of the plate frame and the outer ring of the bipolar plate, melt the laser welding ribs with the laser welding machine, weld and fix the plate frame and the outer ring of the bipolar plate to obtain finished battery assembly C1 and battery assembly C2.

18. The production process of a modular flow battery stack according to any one of claims 14 to 17, characterized in that: The following steps are also included: The liquid flow battery stack is externally encapsulated by a packaging film structure.

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