Reinforced membrane assembly and vanadium flow battery stack

Abstract

The application provides a reinforced membrane assembly and a vanadium flow battery stack, and belongs to the technical field of flow battery. The reinforced membrane assembly comprises an ion exchange membrane and a frame arranged at the peripheral region of the ion exchange membrane, and the frame is arranged in direct contact with the ion exchange membrane; the frame comprises a deposited layer, and the deposited layer and the ion exchange membrane are connected through fusion; or the frame comprises a plurality of deposited layers arranged in a stack, and the adjacent deposited layers and the deposited layer and the ion exchange membrane are connected through fusion to form an integrated structure. By arranging the frame with a layered structure at the peripheral region of the ion exchange membrane, the mechanical strength and dimensional stability of the ion exchange membrane can be improved, the flexible membrane is convenient to clamp, position and automatically assemble; at the same time, the frame and the ion exchange membrane are directly connected through fusion, and an adhesive layer is not needed, the connection reliability and long-term operation stability of the membrane assembly are improved, and the assembly efficiency and use reliability of the battery are improved.

Description

Technical Field

[0001] This application relates to the field of flow batteries, and more particularly to a reinforced membrane module and a vanadium redox flow battery stack. Background Technology

[0002] Ion exchange membranes play a role in blocking the positive and negative electrolytes and preventing internal leakage in flow battery stacks. However, existing ion exchange membranes lack sufficient rigid support, making automated clamping and positioning difficult, resulting in low assembly efficiency and hindering large-scale automated production of the stacks. Furthermore, existing membrane frame structures often use adhesive bonding between the frame and the membrane, which is not very reliable. Summary of the Invention

[0003] The main objective of this application is to provide a reinforced membrane assembly and a vanadium redox flow battery stack that can provide effective rigid support for the ion exchange membrane of the vanadium redox flow battery, facilitate automated assembly, and eliminate the need for an adhesive layer, resulting in a simple and reliable structure.

[0004] This application provides a reinforced membrane assembly, comprising: An ion exchange membrane having an active region and a peripheral region located around the active region; A frame is disposed on the ion exchange membrane and located in the peripheral area. The frame is in direct contact with the ion exchange membrane. The frame includes a deposition layer, wherein the deposition layer and the ion exchange membrane are connected by fusion welding. And / or, the frame includes multiple deposited layers, and the plurality of deposited layers are stacked to form a layered structure, wherein adjacent deposited layers are connected by fusion welding, and the deposited layers are connected to the ion exchange membrane.

[0005] In some embodiments, the layered structure includes: A first deposition layer is disposed in direct contact with the ion exchange membrane; The second deposition layer is disposed on the surface of the first deposition layer away from the ion exchange membrane, and the second deposition layer is disposed in direct contact with the first deposition layer.

[0006] In some embodiments, the frame further includes four side portions located in the peripheral region and a first frame strip, a second frame strip, a third frame strip, and a fourth frame strip disposed corresponding to the four side portions, wherein the first frame strip, the second frame strip, the third frame strip, and the fourth frame strip are sequentially connected to form an annular closed frame surrounding the active region.

[0007] In some embodiments, the frame has the same width and thickness at any location along its extension direction.

[0008] In some embodiments, the length and width of each deposition layer in the layered structure are the same, so that any side of the frame is a vertical plane.

[0009] In some embodiments, the cross-sectional shape of the frame is trapezoidal.

[0010] In some embodiments, the frame has a width of 2 mm to 30 mm and / or a thickness of 0.2 mm to 3 mm.

[0011] In some embodiments, the frame is a non-fluorinated thermoplastic frame.

[0012] In some embodiments, the two opposing surfaces of the frame are parallel to each other, the thickness of each material layer in the layered structure is the same, and / or the thickness of each material layer in the layered structure decreases layer by layer from bottom to top.

[0013] This application also provides a vanadium redox flow battery stack, comprising: electrode; A bipolar plate is disposed opposite to the electrode; And the aforementioned reinforced membrane assembly; The reinforcing membrane assembly is disposed between the electrode and the bipolar plate.

[0014] This application provides a reinforced membrane assembly, which includes an ion exchange membrane and a frame disposed in the peripheral region of the ion exchange membrane. The frame is in direct contact with the ion exchange membrane and includes one or more stacked deposition layers. The deposition layers and the ion exchange membrane, and / or adjacent deposition layers, are fused together to form an integral structure. Thus, the layered frame structure disposed in the peripheral region of the ion exchange membrane provides rigid support for the flexible ion exchange membrane, improving the dimensional stability and mechanical strength of the membrane assembly, making the reinforced membrane assembly easy to clamp, position, and assemble. Simultaneously, since the frame and ion exchange membrane are directly fused together, the reliability and long-term durability of the connection are effectively improved without the need for an additional independent adhesive layer, thereby enhancing the assembly efficiency and operational reliability of the flow battery stack. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a top view of a reinforced membrane assembly provided in an embodiment of this application; Figure 2 This is a cross-sectional view of a reinforced membrane assembly provided in an embodiment of this application; Figure 3 A schematic flowchart illustrating a method for manufacturing a reinforced membrane assembly according to an embodiment of this application; Figure label: 100. Reinforced membrane modules; 10. Ion exchange membrane; 20. Active region; 30. Framework; 31. First deposition layer; 32. Second deposition layer. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] It should be understood that, in order to clearly describe the technical solutions of the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with essentially the same function and effect. For example, the first callback function and the second callback function are only used to distinguish different callback functions and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" do not necessarily mean they must be different.

[0019] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0020] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0021] Vanadium redox flow batteries (VRFBs) differ structurally from membrane electrochemical devices such as proton exchange membrane fuel cells. In VRFB stacks, porous carbon felt electrodes are typically placed on both sides of the ion exchange membrane. These carbon felt electrodes have a relatively large thickness, for example, 2 mm to 6 mm, and a high porosity, for example, approximately 90% to 95%. During stack operation, the positive and negative electrolytes circulate separately on both sides of the membrane.

[0022] Because carbon felt electrodes have considerable thickness and flexibility, during fuel cell stack assembly, the flexible ion exchange membrane must first be individually positioned between the electrode frame or bipolar plates before the electrodes, bipolar plates, and other components are stacked sequentially. Therefore, in the automated assembly of fuel cell stacks, the ion exchange membrane needs to possess certain dimensional stability and gripping properties to facilitate robotic grasping, positioning, and handling.

[0023] However, existing ion exchange membranes are typically thin, flexible sheets with insufficient rigidity, making them prone to wrinkling, misalignment, or deformation during automated assembly, leading to reduced positioning accuracy. Therefore, this application addresses these issues by providing a reinforced membrane assembly suitable for vanadium redox flow battery stack assembly. By incorporating an integrally integrated frame structure into the inactive region of the ion exchange membrane, the mechanical rigidity and dimensional stability of the membrane are improved, enabling reliable gripping, positioning, and assembly by automated equipment. Simultaneously, the frame structure avoids affecting the electrochemical performance of the active region of the ion exchange membrane.

[0024] like Figure 1 and Figure 2 As shown, this application provides a ruggedized membrane assembly for use in a vanadium redox flow battery stack. The ruggedized membrane assembly includes an ion exchange membrane 10 and a frame 30.

[0025] The ion exchange membrane 10 is used to separate the positive and negative electrolytes and selectively conduct ions. The frame 30 is disposed in the peripheral region outside the active region 200 of the ion exchange membrane 10 and is used to provide mechanical support for the ion exchange membrane 10.

[0026] Since the ion exchange membrane 10 is typically a thin, flexible membrane, it is prone to bending, wrinkling, or deformation without a supporting structure, which is detrimental to gripping, positioning, and stacking operations during fuel cell assembly. The embodiments of this application provide a frame 30 in the peripheral region of the ion exchange membrane 10, forming an integrated reinforcing structure with the ion exchange membrane 10. This improves the overall stiffness and dimensional stability of the ion exchange membrane 10, making the reinforced membrane assembly more suitable for automated assembly processes.

[0027] like Figure 1 As shown, the ion exchange membrane 10 is an ion exchange membrane for a flow battery, which can be a perfluorosulfonic acid membrane, such as a Nafion membrane, or a non-fluorine ion exchange membrane. The thickness of the ion exchange membrane 10 can be from 20 μm to 200 μm.

[0028] The ion exchange membrane 10 includes an active region 20 and a peripheral region surrounding the active region 20. The active region 20 is the effective region within the ion exchange membrane 10 that participates in the electrochemical reaction. During stack operation, the active region 20 is positioned opposite the electrode to achieve selective ion conduction. The peripheral region is located around the active region 20 and surrounds it. This peripheral region does not serve as the primary electrochemical reaction region but instead supports the frame 30, allowing the frame 30 to be positioned at the edge of the ion exchange membrane 10.

[0029] By dividing the ion exchange membrane 10 into an active region 20 and a peripheral region, the electrochemical functional region and the mechanical support region are separated. The active region 20 is used to ensure the electrochemical performance of the ion exchange membrane 10, while the peripheral region is used to house the frame 30 to improve the mechanical stability of the membrane module, thereby preventing the frame 30 from obstructing or affecting the active region 20.

[0030] like Figure 1 and Figure 2 As shown, the frame 30 is disposed in the peripheral area of ​​the ion exchange membrane 10 and is in direct contact with the ion exchange membrane 10. The frame 30 is completely located outside the active region 20 in the planar direction of the ion exchange membrane 10, that is, the frame 30 only covers the inactive region of the ion exchange membrane 10 and does not cover the active region 20.

[0031] Specifically, the frame 30 is formed within the contour of the ion exchange membrane 10. Specifically, in the planar direction of the ion exchange membrane 10, the frame 30 does not extend beyond the outer edge of the ion exchange membrane 10; simultaneously, the frame 30 is disposed around the active region 20 and maintains a distance from the active region 20. Since the frame 30 does not cover the active region 20, the frame material can be prevented from hindering effective contact between the ion exchange membrane 10 and the electrode, thereby ensuring that the ion exchange membrane 10 can normally perform its ion-selective conduction function.

[0032] The frame 30 and the ion exchange membrane 10 are not connected by a separate adhesive layer, but are formed as an integral structure through direct contact. Since the frame 30 is directly disposed in the peripheral area of ​​the ion exchange membrane 10, no additional adhesive layer is required. This avoids the problems of aging, softening or falling off of the adhesive due to long-term immersion in electrolyte and temperature changes in traditional adhesive structures, and improves the long-term reliability of the connection between the frame 30 and the ion exchange membrane 10.

[0033] In another embodiment, the frames 30 can also be disposed on both surfaces of the ion exchange membrane 10. Specifically, a first frame is formed in the peripheral region of the first surface of the ion exchange membrane 10, and a second frame is formed in the corresponding peripheral region of the second surface of the ion exchange membrane 10. By providing frames on both sides, the overall stiffness of the ion exchange membrane 10 can be further improved, and the structural stability of the membrane assembly in the thickness direction can be enhanced.

[0034] like Figure 2 As shown, the frame 30 includes multiple deposition layers, which are sequentially stacked along the thickness direction of the ion exchange membrane 10 to form a frame with a layered structure. Adjacent deposition layers are connected by fusion welding, and the bottommost deposition layer is also connected to the ion exchange membrane 10 by fusion welding, so that the multiple deposition layers and the ion exchange membrane 10 form an integral connection structure.

[0035] In some embodiments, the layered structure includes a first deposition layer 31 and a second deposition layer 32. The first deposition layer 31 is disposed on the ion exchange membrane 10 and is in direct contact with the ion exchange membrane 10; the second deposition layer 32 is disposed on the side of the first deposition layer 31 away from the ion exchange membrane 10 and is in direct contact with the first deposition layer 31. The first deposition layer 31 and the ion exchange membrane 10 are connected by fusion welding, and the second deposition layer 32 and the first deposition layer 31 are connected by fusion welding. The fusion welding between the first deposition layer 31 and the ion exchange membrane 10 allows the frame 30 to be directly fixed to the membrane surface without the need for additional adhesives; and the fusion welding between adjacent deposition layers forms a continuous connection, eliminating independent connection interfaces within the layered structure that are prone to peeling, thus improving the overall reliability of the frame.

[0036] In other embodiments, the layered structure may include three or more deposited layers, each layer stacked sequentially along the thickness direction of the ion exchange membrane 10, with adjacent deposited layers connected by fusion to form a continuous structure. The double- or multi-layer stacked structure increases the overall thickness and rigidity of the frame, giving the membrane module better dimensional stability and operational stiffness.

[0037] In other embodiments, the frame 3 includes a single deposited layer, which is directly fused to the peripheral surface of the ion exchange membrane 10. Specifically, the single deposited layer is made of a thermoplastic material, deposited on the peripheral area of ​​the ion exchange membrane 10 in a molten state, and forms the frame 3 after cooling and solidification. Compared to the structure of a multi-layered deposited layer, the single-layered deposited layer simplifies the manufacturing process, requiring only one deposition to complete the formation of the frame 3, reducing time and raw material costs, and also reducing the frame thickness.

[0038] Each deposition layer is formed of a thermoplastic material, and adjacent deposition layers can use the same material. The number of deposition layers can be adjusted according to the required thickness of the frame, for example, from 2 to 100 layers. By adjusting the number of deposition layers, the overall thickness of the frame 30 can be changed, thereby meeting the requirements of different flow battery stack structures for membrane module thickness and support strength.

[0039] like Figure 1 As shown, in one embodiment, the ion exchange membrane 10 is a rectangular membrane sheet having a first direction extending along its length and a second direction extending along its width. The peripheral region includes four side portions extending along the first and second directions, respectively. The frame 30 includes: a first frame strip corresponding to the first side portion; a second frame strip corresponding to the second side portion; a third frame strip corresponding to the third side portion; and a fourth frame strip corresponding to the fourth side portion. The first, second, third, and fourth frame strips are sequentially connected to form a closed annular frame surrounding the active region 20. By adopting a closed annular structure, the frame 30 can continuously provide support around the ion exchange membrane 10, ensuring uniform constraint on the membrane sheet and reducing the risk of wrinkles, deformation, or even breakage caused by concentrated stress in local areas.

[0040] like Figure 2 As shown, in some embodiments, the cross-sectional shape of the frame 30 can be rectangular.

[0041] Specifically, each deposited layer in the layered structure has the same width along the surface direction of the ion exchange membrane 10, such that the deposited layers are sequentially aligned in a direction perpendicular to the surface of the ion exchange membrane 10, thereby forming a vertical plane on the side of the frame 30. Through this structure, the boundaries of each deposited layer remain consistent in the horizontal direction, giving the frame 30 a regular rectangular cross-sectional structure. On the one hand, the regular rectangular structure facilitates the processing and shaping of the frame 30 and its dimensional control; on the other hand, the frame 30 has a flat sidewall structure, which facilitates contact and positioning of mechanical clamps with the sidewalls of the frame 30, thereby improving the gripping stability and positioning accuracy of the reinforced membrane assembly during automated assembly.

[0042] In other embodiments, the cross-sectional shape of the frame 30 may be trapezoidal.

[0043] Specifically, the width of each deposited layer in the layered structure decreases progressively from bottom to top along the surface of the ion exchange membrane 10. That is, the deposited layer closer to the ion exchange membrane 10 is wider, while the deposited layer farther away from the ion exchange membrane 10 is narrower, thus forming a trapezoidal cross-section structure for the frame 30. By setting the trapezoidal cross-section structure, the bottom region near the ion exchange membrane 10 has a larger contact area, thereby increasing the bonding area between the frame 30 and the ion exchange membrane 10 and improving the connection strength between the frame 30 and the membrane.

[0044] In some embodiments, the frame 30 has the same width and thickness at any location along its extension direction.

[0045] Specifically, when the frame 30 is a closed annular structure, the cross-sectional dimensions of the frame 30 remain consistent at all locations along the extension directions of the first, second, third, and fourth frame strips. This structure enables the frame 30 to form a uniformly distributed support structure around the ion exchange membrane 10, ensuring that each region of the frame 30 has a substantially consistent load-bearing capacity. Simultaneously, the consistency of the frame 30's dimensions helps improve the consistency of the reinforced membrane modules, allowing multiple membrane modules to maintain a unified positioning reference during fuel cell assembly and enhancing stability during batch assembly.

[0046] In some embodiments, the two opposing surfaces of the frame 30 are parallel to each other, and the deposited layers in the layered structure may have the same thickness.

[0047] Specifically, the deposition layers are stacked sequentially along the thickness direction of the ion exchange membrane 10, and the thickness of each deposition layer is basically the same, so that a uniform layered structure is formed inside the frame 30. Through the above structure, each deposition layer has similar structural dimensions, so that when the frame 30 is subjected to external forces, each layer can participate in bearing the load together, and the impact load can be evenly distributed among multiple deposition layers, thereby improving the overall structural stability of the frame 30.

[0048] In other embodiments, the thickness of each deposited layer in the layered structure can decrease progressively from bottom to top. That is, the deposited layer closer to the ion exchange membrane 10 is thicker, while the deposited layer farther from the ion exchange membrane 10 is thinner, creating a thickness gradient structure inside the frame 30. By setting the above gradient structure, the side of the frame 30 closer to the ion exchange membrane 10 has higher support strength, while the side farther from the ion exchange membrane 10 has better buffering capacity. When the frame 30 is subjected to pressing force or external impact, the thicker bottom deposited layer can bear the main load, while the thinner top deposited layer can absorb some energy through its own deformation, thereby reducing the possibility of the impact force being directly transmitted to the ion exchange membrane 10 and improving the overall impact resistance of the membrane module.

[0049] In some embodiments, the frame 30 has a width of 2 mm to 30 mm and a thickness of 0.2 mm to 3 mm.

[0050] The width of the frame 30 refers to its extension dimension along the surface of the ion exchange membrane 10, and the thickness of the frame 30 refers to its dimension along the thickness direction of the ion exchange membrane 10. By setting the width of the frame 30 to 2mm to 30mm, sufficient bonding area between the frame 30 and the ion exchange membrane 10 can be ensured while avoiding the frame 30 occupying too much membrane space, thus balancing connection strength and effective utilization area of ​​the membrane module. By setting the thickness of the frame 30 to 0.2mm to 3mm, the overall rigidity of the ion exchange membrane 10 can be improved, enhancing mechanical support capabilities, while avoiding an increase in the overall thickness of the fuel cell stack due to excessive frame thickness, which helps maintain the compactness of the flow battery stack structure.

[0051] In some embodiments, the frame 30 is a thermoplastic frame.

[0052] Specifically, the frame 30 can be made of at least one of polylactic acid (PLA), a blend of polybutylene adipate terephthalate and polylactic acid (PBAT / PLA), or styrene-ethylene-butene-styrene block copolymer-based thermoplastic elastomer (SEBS). All of these materials are non-fluorinated thermoplastics, possessing good processing properties and material availability, which helps reduce the manufacturing cost of the frame 30 compared to traditional fluoropolymer materials.

[0053] PLA material possesses high stiffness and dimensional stability, making it suitable for applications requiring strong mechanical support. By using PLA to form the frame 30, the overall rigidity of the ion exchange membrane 10 can be effectively improved, making the membrane module more suitable for automated clamping and positioning.

[0054] The PBAT / PLA blend material has both rigidity and flexibility, which can improve the bending resistance of the frame 30 and reduce the risk of brittle fracture while ensuring the supporting function of the frame 30.

[0055] SEBS-based thermoplastic elastomers have good elasticity and fatigue resistance. When the frame 30 is formed using this material, the frame 30 can not only provide mechanical support, but also improve the sealing adaptability by utilizing its own elastic deformation capability. Thus, in some embodiments, it also has an auxiliary sealing function, which helps to reduce the number of independent sealing structures in the fuel cell stack.

[0056] By using thermoplastic materials to form the frame 30, the frame 30 can form a fusion connection with the ion exchange membrane 10 and the adjacent deposited layers, thereby avoiding the aging and failure problems that may occur in the adhesive layer in the traditional adhesive bonding method, and improving the stability and reliability of the reinforced membrane module in the long-term operating environment of the flow battery.

[0057] In this embodiment, the reinforced membrane assembly can be formed into a frame 30 by melt deposition molding. Specifically, by heating a thermoplastic material to a molten state and depositing the molten thermoplastic material layer by layer on the peripheral area of ​​the ion exchange membrane 10, multiple sequentially stacked deposition layers of thermoplastic material are formed on the surface of the ion exchange membrane 10, thereby forming a frame 30 with a layered structure.

[0058] During this formation process, the molten thermoplastic material comes into direct contact with the ion exchange membrane 10 and forms a fusion bond with the ion exchange membrane 10 during cooling and solidification. Simultaneously, adjacent deposited layers also fuse together to form a continuous connection structure, thereby creating an integrated reinforced structure between the frame 30 and the ion exchange membrane 10. The frame 30 formed in this way eliminates the need for a separate adhesive layer, improving the mechanical strength of the ion exchange membrane 10 while reducing structural reliability issues caused by adhesive interface failure.

[0059] It should be noted that the frame 30 in this embodiment is mainly used to improve the mechanical stability of the ion exchange membrane 10 during the fuel cell stack assembly process, and is not used to replace the sealing structure after the fuel cell stack is assembled.

[0060] Specifically, during the assembly of the fuel cell stack, after the ion exchange membrane 10, frame 30, electrodes, and bipolar plates are stacked in sequence, the electrolyte can still be sealed by the sealing gaskets, sealing rings, or other sealing structures provided in the fuel cell stack.

[0061] In some embodiments that achieve multi-layer deposition, such as Figure 3 As shown, the formation process of the frame 30 includes steps S101 to S106.

[0062] S101, provides ion exchange membranes.

[0063] First, an ion exchange membrane 10 is provided. The ion exchange membrane 10 includes an active region 20 and a peripheral region surrounding the active region 20. The ion exchange membrane 10 is a bare membrane, meaning that no catalyst coating, gas diffusion layer, or pre-formed adhesive layer is provided on its surface.

[0064] The ion exchange membrane 10 is placed on the processing platform and positioned to keep it flat.

[0065] For example, before the framework is formed, the ion exchange membrane 10 may be pretreated, such as by cleaning, to remove dust, grease or other contaminants from the membrane surface, thereby improving the bonding effect between the subsequent thermoplastic material and the ion exchange membrane 10.

[0066] Using a bare membrane as the substrate for the frame 30 allows the subsequently deposited thermoplastic material to directly contact the surface of the ion exchange membrane 10. When the thermoplastic material is in a molten state, it can fully wet the membrane surface and bond with the microstructure of the membrane surface, thereby improving the connection strength between the frame 30 and the ion exchange membrane 10.

[0067] S102, Provide thermoplastic materials.

[0068] The thermoplastic material used to form the frame 30 is supplied to a fused deposition modeling apparatus. The thermoplastic material may be pre-prepared in the form of filaments, i.e., thermoplastic filaments.

[0069] In some embodiments, the thermoplastic material may be selected from: polylactic acid (PLA), a blend of polybutylene adipate terephthalate and polylactic acid (PBAT / PLA), and styrene-ethylene-butene-styrene block copolymer-based thermoplastic elastomer (SEBS). All of these materials can form a molten state upon heating and re-solidify upon cooling to form a framework structure with a certain mechanical strength.

[0070] S103, melt extrusion thermoplastic material.

[0071] The thermoplastic filament is fed into the heating component of the fused deposition modeling (FDM) equipment to heat it to a molten state; the molten thermoplastic material is extruded through a nozzle and deposited onto the surface of the ion exchange membrane 10.

[0072] Specifically, different nozzle temperatures can be selected based on the melting characteristics of different thermoplastic materials.

[0073] For example, when using PLA material, the nozzle temperature can be set to 190°C to 210°C; when using PBAT / PLA blend material, the nozzle temperature can be set to approximately 180°C; and when using SEBS-based thermoplastic elastomer, the nozzle temperature can be set to 150°C to 180°C. By controlling the nozzle temperature and extrusion speed, the thermoplastic material maintains appropriate flowability, allowing it to spread sufficiently during deposition and form good contact with the surface of the ion exchange membrane 10.

[0074] S104, the first sedimentary layer 31 is formed.

[0075] The nozzle is controlled to move along a preset path, causing molten thermoplastic material to be deposited on the peripheral area of ​​the ion exchange membrane 10. The preset path corresponds to the extension direction of the frame 30 to be formed, i.e., to the outline position of the frame 30; the position of this path is determined by the distance between the outer edge of the ion exchange membrane 10 and the boundary of the active region 20, ensuring that the formed frame 30 is located around the active region 20. By using a closed path to form the frame 30, the frame 30 can continuously surround the active region 20, providing continuous support around the ion exchange membrane 10.

[0076] For example, the preset path corresponds to the outline of the area surrounding the ion exchange membrane 10, and may be a rectangular closed path or a polygonal closed path.

[0077] Because the thermoplastic material is in a molten state, it can wet to a certain extent when it comes into contact with the ion exchange membrane 10 and penetrate into the microstructure of the ion exchange membrane 10 surface. After the thermoplastic material cools and solidifies, a first deposition layer 31 is formed that is directly connected to the ion exchange membrane 10. The first deposition layer 31 and the ion exchange membrane 10 are connected by fusion welding.

[0078] With the above structure, the first deposition layer 31 of the frame 30 can be fixed to the surface of the ion exchange membrane 10 without the need for additional adhesive, thus achieving an integrated bond between the frame 30 and the membrane.

[0079] In other embodiments, no further deposition layers are added; that is, after the first deposition layer 31 is formed, the material is allowed to cool and solidify to obtain a reinforced membrane assembly with a frame 30.

[0080] S105, forming a layered frame structure layer by layer.

[0081] When a multi-layer deposition structure is required, after the formation of the first deposition layer 31, a second deposition layer 32 is formed on the side of the first deposition layer 31 away from the ion exchange membrane 10. The second deposition layer 32 is formed using the same or different thermoplastic material as the first deposition layer 31 and is deposited on the surface of the first deposition layer 31 in a molten state.

[0082] Since the second deposition layer 32 is still in a molten state when it is formed, thermal fusion will occur at the interface between it and the first deposition layer 31, so that the second deposition layer 32 and the first deposition layer 31 are connected as one.

[0083] Furthermore, by repeating the above deposition process, a third and subsequent deposition layers can be formed. Multiple deposition layers are arranged sequentially along the thickness direction of the ion exchange membrane 10, and adjacent deposition layers are connected by fusion welding, thereby forming a frame 30 with a layered structure. By forming deposition layers layer by layer, the number of deposition layers can be adjusted according to actual support requirements, thus flexibly controlling the thickness and mechanical properties of the frame 30. Simultaneously, since the deposition layers are continuously connected by fusion welding, no additional adhesive material is required, thereby reducing the number of structural layers and improving the overall reliability of the frame.

[0084] S106. Obtain the reinforced membrane assembly.

[0085] Once all the deposited layers have formed and cooled and solidified, a reinforced membrane assembly with a frame 30 can be obtained.

[0086] The frame 30 is disposed in the peripheral region of the ion exchange membrane 10 and is located outside the active region 20 in the planar direction of the ion exchange membrane 10. The frame 30 includes multiple stacked deposition layers, which are connected to each other and to the ion exchange membrane 10 by fusion welding. Thus, the flexible ion exchange membrane 10 is mechanically supported by the peripheral frame 30, forming a dimensionally stable, easy-to-grip and position reinforced membrane assembly.

[0087] This application also provides a vanadium redox flow battery stack.

[0088] The vanadium redox flow battery stack includes electrodes, bipolar plates, and a hardening film assembly as described above. The bipolar plates are disposed opposite to the electrodes. The hardening film assembly is disposed between the electrodes and the bipolar plates.

[0089] Specifically, in the battery stack, electrodes (such as carbon felt electrodes) are respectively arranged on both sides of the ion exchange membrane 10, and bipolar plates are respectively arranged on the outer side of the electrodes. The frame 30 of the reinforcing membrane assembly is located in the peripheral area of ​​the ion exchange membrane 10, and bears the pressing stress during the pressing process of the battery stack, providing protection for the ion exchange membrane 10 and preventing it from being damaged during the pressing process. The vanadium redox flow battery stack may include multiple single cells connected in series, and each single cell includes the reinforcing membrane assembly as described above. The reinforcing membrane assembly provides rigid support for the ion exchange membrane, improving assembly efficiency and accuracy; at the same time, there is no adhesive layer between the frame and the membrane, which can withstand long-term immersion in the strongly acidic electrolyte of the vanadium redox flow battery, improving the long-term operational reliability of the battery stack.

[0090] The reinforced membrane assembly and vanadium redox flow battery stack provided in this application are applicable to the field of flow battery energy storage technology. This invention uses fused deposition modeling (FDM) technology to directly form a thermoplastic frame onto the peripheral area of ​​the ion exchange membrane. There is no adhesive layer between the frame and the membrane; they are directly connected by welding. The layered structure gives the frame excellent impact resistance and toughness, providing effective rigid support for the ion exchange membrane, facilitating automated assembly of the stack, and allowing it to withstand long-term immersion in the highly acidic electrolyte of the vanadium redox flow battery.

[0091] The foregoing disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described above. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0092] The above embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of protection of this application. Any non-substantial changes and substitutions made by those skilled in the art based on this application shall fall within the scope of protection claimed by this application.

Claims

1. A reinforced membrane assembly, characterized in that, include: An ion exchange membrane having an active region and a peripheral region located around the active region; A frame is disposed on the ion exchange membrane and located in the peripheral area. The frame is in direct contact with the ion exchange membrane. The frame includes a deposition layer, wherein the deposition layer and the ion exchange membrane are connected by fusion welding. And / or, the frame includes multiple deposited layers, and the plurality of deposited layers are stacked to form a layered structure, wherein adjacent deposited layers are connected by fusion welding, and the deposited layers are connected to the ion exchange membrane.

2. The reinforced membrane assembly according to claim 1, characterized in that, The layered structure includes: A first deposition layer is disposed in direct contact with the ion exchange membrane; The second deposition layer is disposed on the surface of the first deposition layer away from the ion exchange membrane, and the second deposition layer is disposed in direct contact with the first deposition layer.

3. The reinforced membrane assembly according to claim 1, characterized in that, The frame also includes four side portions located in the peripheral area and a first frame strip, a second frame strip, a third frame strip, and a fourth frame strip corresponding to the four side portions. The first frame strip, the second frame strip, the third frame strip, and the fourth frame strip are connected in sequence to form an annular closed frame surrounding the active area.

4. The reinforced membrane assembly according to claim 1, characterized in that, The frame has the same width and thickness at any point along its extension direction.

5. The reinforced membrane assembly according to claim 1, characterized in that, The length and width of each deposition layer in the layered structure are the same, so that any side of the frame is a vertical plane.

6. The reinforced membrane assembly according to claim 1, characterized in that, The cross-sectional shape of the frame is trapezoidal.

7. The reinforced membrane assembly according to claim 1, characterized in that, The frame has a width of 2 mm to 30 mm and / or a thickness of 0.2 mm to 3 mm.

8. The reinforced membrane assembly according to claim 1, characterized in that, The frame is a non-fluorinated thermoplastic frame.

9. The reinforced membrane assembly according to claim 1, characterized in that, The two opposing surfaces of the frame are parallel to each other, the thickness of each material layer in the layered structure is the same, and / or the thickness of each material layer in the layered structure decreases layer by layer from bottom to top.

10. A vanadium redox flow battery stack, characterized in that, include: electrode; A bipolar plate is disposed opposite to the electrode; And the reinforced membrane assembly as described in any one of claims 1 to 9; The reinforcing membrane assembly is disposed between the electrode and the bipolar plate.

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