Flow battery pile integrated structure and welding method

Abstract

The invention discloses a flow cell stack integrated structure and a welding method, and relates to the technical field of electrochemical energy storage devices, the method comprises the following steps: respectively arranging welding ribs on an electrode frame and a cover plate, and respectively welding along the welding ribs around two liquid inlet and outlet holes; according to the invention, through the combination of the welding rib structure design and the laser welding process, the continuous and uniform distribution of interface stress is realized, the formation of a microscopic leakage channel caused by local stress concentration of a traditional discrete sealing structure is effectively inhibited, and an integrated battery module comprising five single battery components is formed; according to the galvanic pile formed by connecting and pressing five to seven modules through flexible graphite plates, compared with the scheme that 25 to 35 single batteries are pressed by depending on mechanical pressing and an auxiliary sealing assembly in the prior art, the elastic stress in the galvanic pile is greatly reduced, the consistency of the sealing performance can be maintained in the long-term operation of the galvanic pile, and the service life of the galvanic pile is prolonged. And the method is particularly suitable for complex working conditions with temperature fluctuation and electrolyte pressure change.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemical energy storage devices, in particular to a liquid flow battery stack integrated structure and a welding method. BACKGROUND

[0002] According to the search, the sealing method and structure of the liquid flow battery frame in patent publication No. CN118156538A, on the one hand, the sealing method includes the following steps: coating a first specified thickness of UV glue on the sealing surface of two liquid flow battery frames, and pre-solidifying the first specified time to form a surface sealing glue layer; coating two circles of second specified thickness of UV glue on any one of the surface sealing glue layers, and pre-solidifying the second specified time to form an outer sealing glue circle and an inner sealing glue circle; the ion conductive film is attached to the other surface sealing glue layer, and the sealing surfaces of the two liquid flow battery frames are attached to each other and correspondingly attached, so that the ion conductive film is located in the outer sealing glue circle and on the inner sealing glue circle. On the other hand, the sealing structure is obtained by the above sealing method. Through the sealing method, the problems of large elastic deformation coefficient of the rubber sealing gasket, influence of the battery assembly during the hot melt glue hot pressing process and easy overflow of the glue, and poor reliability of the stack sealing in the prior art are solved.

[0003] The technology in the comparative document improves efficiency by simplifying the assembly steps, but the implementation process needs to strictly control the thickness of the adhesive coating to be accurate to ±0.1mm, which puts high requirements on the precision of the glue coating equipment, and the interface rigidity is high after solidification, which is difficult to adapt to the thermal expansion deformation in the operation of the stack. In addition, the working condition requirements are also relatively harsh, the environmental temperature range needs to be controlled at 15-25℃ and the humidity range needs to be controlled at 50%-70% RH, in order to avoid insufficient curing of the glue layer or accumulation of internal stress. At the same time, the operation requires the operator to wear safety protection measures under the UV glue curing lamp, which increases the safety cost and potential operation risk. In summary, the comparative document still has the following shortcomings:

[0004] (1) The sealing interface relies on discrete connection: the bolt or adhesive process applies force through local points, which is difficult to achieve continuous and uniform distribution of interface stress, resulting in a significant decrease in sealing reliability over time.

[0005] (2) Insufficient material compatibility and durability: the rubber sealing ring is prone to swelling and aging in strong acid electrolyte, and the ultraviolet curing adhesive has limited temperature resistance, which are difficult to meet the long-term operation requirements of the liquid flow battery.

[0006] (3) Structural redundancy and process complexity: the introduction of rubber sealing rings or glue layers increases the number of components and assembly steps, and the processing precision is demanding, with micron-level precision required for glue layer thickness control, which increases the manufacturing cost and failure rate.

[0007] (4) Lack of dynamic adaptability: existing sealing interfaces rely on static pre-tightening force or rigid bonding, which is difficult to effectively compensate for the interface micro-displacement caused by temperature fluctuations or electrolyte pressure changes during stack operation, and the leakage rate increases exponentially after long-term operation.

[0008] Therefore, the liquid flow battery stack integrated structure and welding method are proposed to solve the above problems. SUMMARY

[0009] Therefore, the technical problem to be solved by the present application is to provide a liquid flow battery stack integrated structure and welding method, which optimizes the distribution density and geometric parameters of the welding ribs, combines with the laser welding process, realizes the efficient integrated integration of the multi-layer electrode frame assembly, and solves the technical bottlenecks of insufficient sealing and complex process.

[0010] To achieve the above purpose, the present application provides the following technical scheme: a liquid flow battery stack integrated structure and welding method, comprising:

[0011] S1, welding ribs are arranged on the outer side of the electrolyte flow channel, the outer edge of the electrode side of the whole electrode frame, and the two electrolyte inlet and outlet holes on the electrode frame away from the cover plate, respectively, and double-sided laser welding is performed along the four edges of the bipolar plate and the four edges of the first and second electrode frames, respectively;

[0012] S2, the four cover plates of each single cell module are welded to the electrode frame along the welding ribs;

[0013] S3, the first electrode is placed in the electrode groove of the first electrode frame, and the second electrode is placed in the electrode groove of the second electrode frame to form a component; repeat five times to form five components;

[0014] S4, according to the different types of liquid flow batteries, install membrane materials with different characteristics and applications in every two components, and weld along the welding ribs of the two liquid inlet and outlet holes, and then weld along the welding ribs of the outer side contour of the electrode frame.

[0015] As a preferred, the laser welding is used to realize the fixation of the bipolar plate and the electrode frame, the packaging of the electrode frame and the cover plate, and the interlayer welding in sequence, after the integrated welding is completed, the copper plate and the end plate are added at both ends, and then the outer sealing is completed by using hot melt glue to form a complete stack, and finally the stack is fixed by screwing.

[0016] As a preferred, during the welding process, the laser power, frequency and welding speed are dynamically adjusted according to the material characteristics, so that the fusion depth of the welding ribs and the contact surface is consistent;

[0017] As a preferred, the electrode is a first electrode, and a second electrode is collectively referred to; the electrode frame is a first electrode frame and a second electrode frame collectively referred to, and the cover plate is a first cover plate, a second cover plate, a third cover plate and a fourth cover plate collectively referred to.

[0018] The flow battery stack integrated structure comprises a single cell module, the integrated battery module is composed of five single cell modules, the inside of each single cell module and the space between every two single cell modules are sealed by laser welding, the integrated battery modules are sealed by flexible graphite plates to form a battery stack, and the assembly of the device is completed by sealing the outer layer of the battery stack with hot melt adhesive, characterized in that a component is composed of a first electrode frame and a second electrode frame with a bipolar plate sandwiched therebetween, the bipolar plate is equal in size to the electrode frame; each component is fixed by welding the welding ribs around the inlet and outlet holes, and welding ribs are symmetrically distributed on the outer side of each component, i.e., the electrode side of the electrode frame.

[0019] As a preferred, the electrode frame adopts the layout of a rectangular reaction cavity in the middle and four circular inlet and outlet holes at four corners, a cover plate is arranged in the flow channel area to prevent direct contact of the positive and negative electrode liquid, and the two surfaces of the electrode frame are respectively welded with the bipolar plate and the cover plate.

[0020] As a preferred, welding ribs consistent with the outer contour of the electrode frame are arranged on the electrode side of the electrode frame, welding ribs with the same size as the outer contour of the cover plate are arranged on the surface of the cover plate, and welding ribs are arranged around the inlet and outlet holes away from the cover plate.

[0021] As a preferred, the welding rib comprises a weld seam and a weld bead, the weld seam is a groove opened on both sides of the weld bead, the weld seam is the main area of the connecting material, and the weld seam fills the molten welding material into the gap to form a complete weld seam; the weld bead is a protruding connecting area on the center line of the welding, and provides heat source and material for the weld bead.

[0022] As a preferred, the weld seam is opened with a width of 2mm, the weld seam is opened with a depth of 0.2mm, the weld bead has a thickness of 0.2mm (relative to the surface of the initial material), and the weld bead has a width of 2mm.

[0023] Compared with the prior art, the present application provides a flow battery stack integrated structure and a welding method, which has the following beneficial effects:

[0024] (1) The present application realizes the continuous and uniform distribution of interface stress by combining the welding rib structure design with the laser welding process, effectively inhibits the formation of micro leakage channels caused by local stress concentration in the traditional discrete sealing structure, forms an integrated battery module containing five single cell components, and forms a stack by connecting and pressing seven to five modules through flexible graphite plates. Compared with the prior art which relies on mechanical pressing and auxiliary sealing components to press 25-35 single cells, the present application significantly enhances the dynamic stability of the sealing layer, greatly reduces the elastic stress inside the stack, can maintain the consistency of the sealing performance in the long-term operation of the stack, and is especially suitable for complex working conditions with temperature fluctuations and electrolyte pressure changes.

[0025] (2) In the structural design level, the geometric optimization of the welding rib and the integration of the electrode frame body eliminate the redundant sealing components such as elastic sealing ring or composite gasket in the traditional scheme, simplify the overall architecture of the battery stack, and reduce the failure risk caused by the assembly error of multiple components. At the same time, the high precision characteristics of the laser welding process ensure the consistency of the fusion depth of the welding rib and the contact surface, avoiding the excessive dependence on high-precision processing in the traditional process, thereby improving the manufacturing efficiency and process fault tolerance.

[0026] (3) From the perspective of engineering application, the technical scheme of the present application significantly improves the cycle life and reliability of the battery stack through the uniform distribution of interface stress. Experimental verification shows that this scheme can effectively adapt to the thermal expansion deformation and mechanical vibration in the operation of the battery stack, reducing the sealing performance degradation caused by material creep or fatigue. In addition, the dynamic adjustability of the welding process parameters provides a technical basis for the compatibility of different material systems, further expanding the application range of the present application.

[0027] In summary, the above effects are verified by simulation analysis and cycle test, and the technical advantages not only lie in the essential improvement of sealing performance, but also in providing a high-reliability and low-complexity technical path for the large-scale manufacturing of liquid flow battery stacks, which has clear industrial application value. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a single component structure schematic diagram of the all-vanadium redox flow battery of the present application;

[0029] Figure 2 is an auxiliary schematic diagram of the single component structure of the all-vanadium redox flow battery of the present application;

[0030] Figure 3 is an integrated welding rib structure schematic diagram of the single component of the all-vanadium redox flow battery of the present application;

[0031] Figure 4 is an enlarged view of A in the present application; Figure 3

[0032] Figure 5 is an enlarged view of B in the present application; Figure 3

[0033] Figure 6 is an exploded schematic diagram of the battery stack structure of the present application;

[0034] Figure 7 is a schematic diagram of the battery stack structure of the present application.

[0035] In the figure:

[0036] ​​1, single cell module; 11, first electrode; 12, first cover plate; 13, second cover plate; 14, first electrode frame; 15, bipolar plate; 16, second electrode frame; 17, second electrode; 18, third cover plate; 19, fourth cover plate; 101, weld; 102, weld bead;

[0037] 2, upper end plate; 3, upper insulating plate; 4, first copper plate; 5, flexible graphite plate; 6, second copper plate; 7, lower insulating plate; 8, lower end plate. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0039] Embodiment 1:

[0040] The integrated structure of the flow battery stack includes a single cell module 1, and flexible graphite plates 5 are symmetrically arranged on both sides of the single cell module 1. Five groups of single cell modules 1 and flexible graphite plates 5 are arranged, and the five groups of single cell modules 1 and flexible graphite plates 5 are composed of a single cell module 1, an upper end plate 2 and a first copper plate 4 on one side, and a second copper plate 6, a lower insulating plate 7 and a lower end plate 8 on the other side.

[0041] The single cell module 1 includes a bipolar plate 15, and first electrode frames 14 and second electrode frames 16 are arranged on both sides of the bipolar plate 15. The first electrode frame 14 is provided with a first cover plate 12 and a second cover plate 13, and a first electrode 11 is arranged on the side of the first electrode frame 14 close to the second cover plate 13. A third cover plate 18 and a fourth cover plate 19 are arranged on the side of the second electrode frame 16 away from the bipolar plate 15, and a second electrode 17 is arranged in the middle of the side of the second electrode frame 16 away from the bipolar plate 15. A proton exchange membrane is arranged on the second electrode frame 16.

[0042] Welding ribs are symmetrically distributed on the upper and lower ends of the electrode side of the electrode frame. Rectangular reaction cavities and four circular liquid inlet and outlet holes are arranged in the middle of the first electrode frame 14 and the second electrode frame 16. Cover plates are arranged in the flow channel area of the rectangular reaction cavities of the first electrode frame 14 and the second electrode frame 16 to prevent direct contact of the positive and negative electrode liquids. The double sides of the electrode frame are respectively welded with the bipolar plate 15 and the cover plate.

[0043] Welding ribs consistent with the outer contour of the electrode frame are arranged on the electrode side of the electrode frame. Welding ribs with the same size as the outer contour of the cover plate are arranged on the surface of the cover plate. Welding ribs with the same size as the outer periphery of the liquid outlet hole are arranged on the liquid inlet and outlet holes.

[0044] The welding rib includes a weld seam 101 and a weld bead 102. The weld seam 101 is a groove opened on both sides of the weld bead 102. The weld seam 101 is the main area for connecting materials. The weld seam 101 fills the melted welding material into the gap to form a complete weld seam; the weld bead 102 is a protruding connection area on the welding center line, providing heat source and materials for the weld bead.

[0045] Among them, the parameters of the welding rib are as follows:

[0046] The opening width of the weld seam 101 is 2 mm;

[0047] The opening depth of the weld seam 101 is 0.2 mm;

[0048] The thickness of the weld bead 102 is 0.2 mm;

[0049] The width of the weld bead 102 is 2 mm.

[0050] The welding composition method of the all-vanadium redox flow battery in the specific implementation process of the above embodiment is as follows:

[0051] As Figure 1 shown, take an example that a module of the all-vanadium redox flow battery includes five components. The single component of this device includes, from left to right: the first electrode 11, the first cover plate 12, the second cover plate 13, the first electrode frame 14, the bipolar plate 15, the second electrode frame 16, the second electrode 17, the third cover plate 18, the fourth cover plate 19, and the proton exchange membrane. As Figure 1 shown. The five components are connected in series, and each two components are separated by a proton exchange membrane. The bilateral dimensions of the proton exchange membrane are slightly larger than those of the electrodes. The proton exchange membrane is fixed to the second electrode frame by using a soldering film for welding. When multiple modules are connected in series, each two modules are connected in series with a flexible graphite plate 5. After the series connection is completed, a flexible graphite plate 5 is added to both ends of the five groups of battery components.

[0052] The welding and installation method of the all-vanadium single cell module 1 is as follows:

[0053] (1) Laser-weld the bipolar plate 15 on both sides to two electrode frames respectively; a total of five groups are welded;

[0054] (2) Weld each group of four cover plates to the electrode frame along the welding rib respectively;

[0055] (3) Place the first electrode 11 in the electrode groove of the first electrode frame 14, and place the second electrode 17 in the electrode groove of the second electrode frame 16 to obtain a component; repeat five times to obtain five components;

[0056] (4) Put the proton exchange membrane in each two components, and fix the proton exchange membrane on the two side electrodes by using the soldering film welding; weld the welding ribs around the two inlet and outlet holes first, and then weld the welding ribs along the outer side contour of the electrode frame. Repeat four times to obtain a battery module;

[0057] The electrode frame and the cover plate are both made of HDPE plate, and the bipolar plate 15 is made of HDPE conductive plastic.

[0058] The laser welding parameters of the welding rib on the electrode frame made of HDPE plate are as follows:

[0059] The laser welding power ranges from 150 to 160 w;

[0060] The laser welding speed ranges from 18 to 25 mm / s;

[0061] The welding parameters of the welding rib on the bipolar plate 15 made of HDPE conductive plastic are as follows:

[0062] The laser welding power ranges from 125 to 135 w;

[0063] The laser welding speed ranges from 18 to 25 mm / s;

[0064] As shown in FIG. 1, a stack structure of the device includes a single cell module 1, an upper end plate 2, an upper insulating plate 3, a first copper plate 4, a flexible graphite plate 5, a second copper plate 6, a lower insulating plate 7, and a lower end plate 8. Figure 7

[0065] (1) Repeat the operation of the single cell module 14 in the welding and installation of the all-vanadium single cell module 1 five times to obtain five modules. The five modules are connected in series, and a flexible graphite is added between every two modules to obtain a stack composed of five series-connected modules.

[0066] (2) Seal the periphery of the stack with hot melt glue.

[0067] (3) Add copper plates, insulating plates, and end plates at both ends of the stack, and complete the assembly by clamping with bolts to obtain an all-vanadium flow battery stack.

[0068] The existing stack forming method is as follows:

[0069] Compared with the structure of the conventional all-vanadium flow battery, 25 single cells are connected in series. After the twenty-five single cells are connected in series, they are compressed and assembled according to the structure of the all-vanadium flow battery, and are fixed by bolts.

[0070] (1) Put the bipolar plate 15 in two electrode frames, cover the first cover plate 12 and the second cover plate 13, put the electrodes into the grooves, cover the sealing gasket, cover the proton exchange membrane, and complete the assembly of the remaining single cells symmetrically to obtain a single cell.​

[0071] (2) Repeat operation 1 in the comparative example twenty-five times, and obtain twenty-five groups of single cells in series; add a bipolar plate 15 at the rear end of the last group of single cells;

[0072] (3) Install gaskets, copper plates, insulating plates and end plates at the upper and lower ends of the twenty-five groups of single cells in sequence, clamp and fix with bolts to obtain a full vanadium flow battery stack.

[0073] Through experimental comparison, the advantages of the present scheme over the comparative scheme are as shown in Table 1.

[0074] Table 1 is a comparison table of the efficiency of each parameter of the full vanadium flow battery;

[0075]

[0076] Example 2, as shown in Figure 1 The welding method of the zinc-bromine flow battery is as follows:

[0077] Take a module of the zinc-bromine flow battery as an example, which includes five components. The single component of the device includes, from top to bottom, a first cover plate 12, a second cover plate 13, a first electrode frame 14, a bipolar plate 15, a second electrode frame 16, a second electrode 17 and a third cover plate 18. The five components are connected in series, and each two components are separated by a porous membrane. The porous membrane is fixed on both sides of the second electrode frame by laser welding. A flexible graphite plate 5 is added to each end of the five battery components. When multiple modules are connected in series, a flexible graphite plate 5 is used to connect each two modules. A battery module of the device includes, from top to bottom, a bipolar plate 15, a first component, a first porous membrane, a second component, a second porous membrane, a third component, a third porous membrane, a fourth component, a fourth porous membrane, a fifth component and a bipolar plate 15.

[0078] (1) Laser weld the bipolar plate 15 on both sides of the two electrode frames respectively; a total of five groups are welded;

[0079] (2) Weld each group of four cover plates to the electrode frame along the welding ribs; repeat 5 times to obtain five components;

[0080] (3) Put a porous membrane between each two components, and weld the porous membrane on both sides of the bipolar plate 15 by laser welding. Weld along the welding ribs around the two liquid inlet and outlet holes, and then weld along the welding ribs outside the electrode frame. Repeat four times to obtain five series components;

[0081] (4) Add a flexible graphite plate to each end of the five series components to obtain a battery module;

[0082] The porous membrane is made of PE polyethylene or PP polypropylene, and the electrode frame and cover plate are made of the same material as the porous membrane.

[0083] Laser welding parameters of welding ribs on electrode frame material PE polyethylene or PP polypropylene:

[0084] Laser welding power range 160-170w;

[0085] Laser welding speed range 18-25mm / s;

[0086] The zinc-bromine flow battery stack of the present scheme is composed as follows:

[0087] Take one zinc-bromine flow battery stack including five modules as an example. The structure of one stack of the device includes: upper end plate 2, upper insulating plate 3, first copper plate, five battery modules composed of five groups of single battery modules 1 and flexible graphite plate 5 in series, second copper plate 6, lower insulating plate 7 and lower end plate 8. The end plate material is aluminum alloy.

[0088] (1) Repeat the single battery module 15 five times to obtain five modules. After one battery module is connected in series, add a flexible graphite, repeat four times, and obtain a stack composed of five series modules;

[0089] (2) Seal the periphery of the stack with hot melt glue;

[0090] Add copper plates, insulating plates and end plates at both ends of the stack, clamp with bolts to complete assembly, and obtain a zinc-bromine flow battery stack.

[0091] The conventional sealing gasket sealing method of the existing comparative example of the zinc-bromine flow battery disclosed is as follows:

[0092] The structure of the conventional zinc-bromine flow battery from top to bottom includes: upper end plate 2, upper insulating plate 3, first copper plate 4, first sealing gasket, twenty-five groups of single batteries in series, second copper plate 6, second sealing gasket, lower insulating plate 7 and lower end plate 8. After the twenty-five single batteries are connected in series, they are assembled by pressing according to the structure of the zinc-bromine flow battery, and fixed with bolts.

[0093] Among them, the existing sealing method is as follows:

[0094] (1) Put the bipolar plate 15 between the two electrode frames, cover the first cover plate 12 and the second cover plate 13, cover the sealing gasket, cover the porous membrane, and symmetrically complete the assembly of the remaining single batteries; obtain a single battery;

[0095] (2) Repeat operation 1 in the comparative example twenty-five times to connect the single batteries to obtain twenty-five groups of single batteries; add the bipolar plate 15 at the end of the last group of single batteries;

[0096] (3) Install the sealing gasket, copper plate, insulating plate and end plate in turn at the upper and lower ends of the twenty-five groups of single batteries, clamp and fix with bolts to obtain a zinc-bromine flow battery stack.

[0097] (4) By the comparative experiment method steps of the above scheme, the advantages of the zinc-bromine flow battery of the scheme and the comparative example are shown in Table 2;

[0098] Table 2 is a comparative statistical table of the parameter efficiency of the zinc-bromine flow battery;

[0099]

[0100] In summary, through the sealing design of the present scheme, the continuous and uniform distribution of interface stress is realized by combining the welding rib structure design and the laser welding process, effectively inhibiting the formation of micro leakage channels caused by local stress concentration in traditional discrete sealing structures, forming an integrated battery module containing five single cell assemblies, and the battery stack formed by five to seven such modules connected and pressed by flexible graphite plates. Compared with the prior art which relies on mechanical pressing and auxiliary sealing components to press the five single cells of the flexible graphite plate 5, the dynamic stability of the sealing layer is significantly enhanced, the elastic stress inside the battery stack is greatly reduced, and the consistency of the sealing performance can be maintained during long-term operation of the battery stack. It is especially suitable for complex working conditions with temperature fluctuations and electrolyte pressure changes.

[0101] In terms of structural design, the geometric optimization of the welding rib and the integration of the electrode frame body eliminate the redundant sealing components such as elastic sealing rings or composite gaskets in traditional schemes, simplify the overall architecture of the battery stack, and reduce the failure risk caused by assembly errors of multiple components. At the same time, the high precision characteristics of the laser welding process ensure the consistency of the fusion depth of the welding rib and the contact surface, avoiding the excessive dependence on high-precision processing in traditional processes, thereby improving the manufacturing efficiency and process fault tolerance.

[0102] From the perspective of engineering application, the technical scheme of the present application significantly improves the cycle life and reliability of the battery stack through the uniform distribution of interface stress. Experimental verification shows that this scheme can effectively adapt to thermal expansion deformation and mechanical vibration during battery operation, reducing the sealing performance degradation caused by material creep or fatigue. In addition, the dynamic adjustability of the welding process parameters provides a technical basis for the compatibility of different material systems, further expanding the application scope of the present application.

[0103] It should be noted that before welding, the present scheme should ensure that there are no impurities in each component, and the electrode frame mentioned in the present scheme refers to the first electrode frame and the second electrode frame, and the cover plate mentioned in the text refers to the first cover plate, the second cover plate, the third cover plate and the fourth cover plate.

[0104] It is to be understood that the terminology "including", "comprising", or other derivatives from the term "contain" are inclusive and that, in addition to the stated combinations, other combinations are also contemplated. It is to be further understood that the term "comprising" or "comprises" does not exclude other elements being present in addition to those listed. It is to be further understood that the term "including" or "includes" does not exclude other elements being present in addition to those listed.

[0105] While embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the embodiments described, since the scope of the application is defined with respect to the appended claims.

Claims

1. A method of welding a flow battery stack integrated structure, characterized by: The application relates to a method for manufacturing a flow battery, which comprises the following steps: S1, welding ribs are arranged on the outer side of an electrolyte flow channel, the outer edge of an electrode frame on the side of a bipolar plate, and the two electrolyte inlet and outlet holes on the electrode frame away from a cover plate, and the welding ribs are double-sided laser welded along the four edges (15) of the bipolar plate and the four edges of a first electrode frame (14) and a second electrode frame (16); S2, four cover plates of each single cell module (1) are welded to the electrode frames along the welding ribs; S3, a first electrode (11) is arranged in an electrode groove of the first electrode frame (14), and a second electrode (17) is arranged in an electrode groove of the second electrode frame (16) to form an assembly; the step is repeated five times to form five assemblies; S4, according to the type of the flow battery, membrane materials with different characteristics and applications are arranged in every two assemblies, and the welding ribs along the two electrolyte inlet and outlet holes are welded, and then the welding ribs along the outer side of the electrode frame are welded.

2. The welding method of claim 1, wherein: The bipolar plate (15) is fixed to the electrode frame, the electrode frame is packaged to the cover plate, and interlayer welding is sequentially realized through laser welding; after integrated welding, copper plates and end plates are arranged at both ends; then, external sealing is realized through hot melt glue to form a complete stack; finally, the stack is fixed through bolts.

3. The welding method of claim 1, wherein: During the welding process, the laser power, frequency and welding speed are dynamically adjusted according to the material characteristics, so that the fusion depth of the welding ribs and the contact surface is consistent; the electrodes are collectively referred to as the first electrode (11) and the second electrode (17); the electrode frames are collectively referred to as the first electrode frame (14) and the second electrode frame (16); and the cover plates are collectively referred to as the first cover plate (12), the second cover plate (13), the third cover plate (18) and the fourth cover plate (19).

4. The flow battery stack integrated structure according to any one of claims 1-3, characterized in that: The single cell module (1) is provided with flexible graphite plates (5) on both sides, and five groups of the single cell module (1) and the flexible graphite plate (5) are arranged in series to form a stack; one side of the stack is provided with a single cell module (1), an upper end plate (2), an upper insulating plate (3) and a first copper plate (4); and the other side of the stack is provided with a second copper plate (6), a lower insulating plate (7) and a lower end plate (8).

5. The flow battery stack integration structure of claim 4, wherein: The single cell module (1) comprises a bipolar plate (15), first and second electrode frames (14) and (16) arranged on both sides of the bipolar plate (15), a first cover plate (12) and a second cover plate (13) arranged on the first electrode frame (14), a first electrode (11) arranged on one side of the first electrode frame (14) close to the second cover plate (13), a third cover plate (18) and a fourth cover plate (19) arranged on one side of the second electrode frame (16) away from the bipolar plate (15), a second electrode (17) arranged in the middle of one side of the second electrode frame (16) away from the bipolar plate (15), and a proton exchange membrane arranged on the second electrode frame (16).

6. The flow battery stack integration structure of claim 5, wherein: The first electrode frame (14) and the second electrode frame (16) are directly welded with bipolar plates, the bipolar plates have the same size as the electrode frames; the first electrode frame (14) is close to the second cover plate (13), welding ribs are designed around the two liquid inlet and outlet ports away from the cover plate, each component is welded and fixed by the welding ribs around the liquid inlet and outlet holes, the outer side of each component, i.e. the electrode side of the electrode frame, is symmetrically distributed with welding ribs at the upper and lower ends.

7. The flow battery stack integration structure of claim 6, wherein: The middle part of the first electrode frame (14) and the second electrode frame (16) is provided with a rectangular reaction cavity and four circular liquid inlet and outlet holes at four corners, the rectangular reaction cavity flow channel area of the first electrode frame (14) and the second electrode frame (16) is provided with a cover plate to prevent direct contact of the positive and negative electrode liquid, the two surfaces of the electrode frame are respectively welded with bipolar plates (15) and cover plates, and the welding ribs are distributed on the electrode side of the electrode frame and the bipolar plates.

8. The flow battery stack integration structure of claim 7, wherein: The electrode side of the electrode frame is provided with welding ribs consistent with the outer contour of the electrode frame, the surface of the cover plate is provided with welding ribs with the same size as the outer contour of the cover plate, and the liquid inlet and outlet holes are provided with welding ribs with the same size as the outer periphery of the liquid outlet hole.

9. The flow battery stack integration structure of claim 8, wherein: The welding rib includes a weld seam (101) and a weld bead (102), the weld seam (101) is a groove opened on both sides of the weld bead (102), the weld seam (101) is a main area of the connecting material, and the weld seam (101) fills the molten welding material into the gap to form a complete weld seam; the weld bead (102) is a convex connecting area on the welding center line, which provides heat source and material for the weld bead.

10. The flow battery stack integration structure of claim 9, wherein: The weld seam (101) has an opening width of 1.5-2.5 mm, the weld seam (101) has an opening depth of 0.15-0.25 mm, the weld bead (102) has a thickness of 0.15-0.25 mm relative to the surface of the initial material, and the weld bead (102) has a width of 1.5-2.5 mm.

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