Method of securing membrane to frame, cell stack and use

Abstract

A method of securing a film between a first frame member and a second frame member, the film having at least one property that imparts incompatibility without securing it to the first and second frame members. The method includes creating a fixed region including a first region and a second region, where creating the first region includes integrally bonding the first frame member to the second frame member, and where creating the second region includes mechanically deforming the membrane between the first frame member and the second frame member. A cell stack and use of an ion exchange membrane in the disclosed cell stack are also provided.

Description

Technical Field

[0001] The present application relates to a method for fixing a membrane, in particular a diaphragm or an ion exchange membrane, to a frame, a unit stack and the use of an ion exchange membrane in the unit stack. Background Art

[0002] The membrane can be fixed in a frame so that the center of the membrane is exposed to allow the membrane to perform its function, such as the exchange of molecules, ions or other particles. The frame can be used to improve the controllability of the membrane or promote the assembly of the membrane into the system. When the membrane is used in a battery cell, a fuel cell or the like (such as an electrodialysis unit or a PEM electrolyzer), the frame can provide the required isolation to prevent short circuits.

[0003] Typical methods of fixing the membrane to the frame include welding, adhesive bonding, mechanical force (such as clamping) or any other method of connection. For some applications, it is essential that the membrane is permanently fixed to the frame to prevent mixing of substances between the two sides of the membrane. For example, in a battery cell, mixing of electrolytes between the two sides of the membrane causes discharge and / or short circuit. In another example, mixing of filtered and unfiltered liquids between the two sides of the membrane causes contamination of the desired result (e.g., filtered liquid).

[0004] The welding process uses heat and pressure to permanently combine two objects together. However, if the welding properties of the two objects are far apart, which prevents the application of heat and pressure to provide a suitable joint, the welding process becomes complicated and sometimes infeasible. In this case, the materials of the two objects will need to be redesigned. Alternatively, adhesive bonding or mechanical force (such as clamping) can be used to promote such objects to be fixed together. However, as can be appreciated, the selected adhesive will need to withstand the close proximity and / or operating environment of the fixed object within a reasonable period of time, and the selected mechanical force needs to be strong enough without causing the destruction of the fixed object.

[0005] Therefore, there is a need to provide a durable and sufficiently tight connection between the membrane and the frame, which overcomes or at least ameliorates the above-described problems and other disadvantages. Summary of the invention

[0006] In one aspect, a method of securing a membrane between a first frame member and a second frame member is provided, the membrane having at least one property that imparts incompatibility and prevents it from being secured to the first and second frame members. The method includes creating a securing region including a first region and a second region. Creating the first region includes integrally bonding the first frame member to the second frame member. Creating the second region includes mechanically deforming the membrane between the first frame member and the second frame member.

[0007] Since the film is not compatible at all and cannot be fixed to the first and second frame members, the present disclosure advantageously provides a fixing area to allow the film to be fixed between the first and second frame members. The film may not be compatible at all and cannot be integrally bonded to the first and / or second frame members. The film may have at least one attribute that confers incompatibility and cannot be integrally bonded to the first and / or second frame members.

[0008] The present disclosure provides a second area in the fixing area to advantageously allow the film to be fixed to the frame member in a manner that is suitable for the fundamental incompatibility of the film and the frame member, i.e., mechanical fixing. At the same time, a first area is provided to allow an integral connection between compatible parts (i.e., the first and second frame members), which advantageously provides additional fixing points. "Fixing area" refers to an area or section relative to the objects to be fixed together, which is intended to be used to fix the film to the frame member. The fixing area may include an area that does not exist in the objects to be fixed together, such as the disclosed first area, wherein the film may not be present, as long as the purpose of the area is to enhance the fastening or fixation of the film.

[0009] Generating the fixing area may include generating the first area and generating the second area. The first area and the second area may be generated simultaneously. The first area and the second area may be generated by a welding process or during a welding process. Advantageously, the disclosed method provides a method for joining objects using a conventional and cost-effective welding process. The disclosed method advantageously provides a method for welding objects that have welding properties that are so far apart that they cannot be joined via known material-based joints. The welding process may be an ultrasonic welding process, a friction welding process, a resistance welding process, or any other suitable type of welding process.

[0010] Producing the first region includes integrally bonding the first frame member to the second frame member. The first region may not include a membrane. There may be no membrane in the first region. Thus, the step of producing the first region may include subjecting the double-layer structure including the first and second frame members to integral bonding.

[0011] The membrane may be disposed between the first and second frame members only in the second region.The method may further comprise disposing the membrane between the first and second frame members only in the second region.

[0012] Producing the second region includes mechanically deforming the film between the first frame member and the second frame member. The step of mechanically deforming may include mechanically deforming the film and one of the first or second frame members against the other frame member. Thus, the step of producing the second region may include subjecting the three-layer structure including the film sandwiched between the first and second frame members to mechanical deformation. The three-layer structure may be mechanically deformed at one, two or more points in the second region.

[0013] The second region can be produced in a manner that integral bonding does not occur or substantially does not occur. The step of producing the second region may not include any integral bonding. Since there is a membrane in the second region, the disclosed step of producing the second region advantageously does not destroy the membrane or a large part or substantial part of the membrane due to fundamental incompatibility of fixation or integral bonding. Due to the broken connection between the membrane and the frame member, the destruction of the membrane or a large part or substantial part of the membrane during fixation may cause undesirable leakage. As described above, the membrane is not firmly sealed to its frame, resulting in the system (such as a battery cell stack) in which the membrane and the frame are located being damaged.

[0014] In some embodiments, the second region may also include the generation of a transition region, in which an integral bond occurs. The step of generating the second region or the step of generating the transition region may include piercing the film, thereby allowing an integral bond to occur between the first frame member and the second frame member through the pierced film. The fixed region may include a transition region. The transition region may include the edge of the film. Since the film may be arranged only in the second region, in such an embodiment, the edge of the film is located in the transition region. The film may be pierced at multiple points or at multiple points along the edge of the film. Providing an integral bond in the presence of the film may advantageously lead to another fixed point. For example, due to the transition region, good tear resistance of the film from the frame member may be obtained. When the film may react adversely in its immediate environment, such as when moisture in the environment causes the film to shrink, the combination of mechanical deformation in the second region and the integral bond in the transition region advantageously reduces leakage during operation of the final system. The environment or the immediate environment may include, for example: the storage environment of the fixed film before being assembled to the final system, such as an environment exposed to air that may have a relative humidity change; the environment during the manufacture or assembly of the final system; or the operating environment of the assembled film in the final system. The film that shrinks in its environment can be pulled away from its fixing area with the frame member, thereby also causing undesirable leakage in the final operating environment. Therefore, in this case, the combination of mechanical deformation in the second area and the integral bonding in the transition area can advantageously reduce leakage. Since the integral bonding occurs in a local and / or point-based manner through the pierced portion of the film, the unpierced portion of the film in the transition area can be held in place by the points of the integral bonding. The destruction of the film at its edge may not cause undesirable leakage because the mechanical deformation in the second area helps to fix the film to the frame.

[0015] The fixing area may include a third area. Generating the fixing area may also include generating the third area. The method may also include generating the third area by mechanically compressing the film using a protrusion of the frame member. The protrusion may be located on the first frame member, the second frame member, a different third frame member, or a combination thereof. Alternatively, the method may also include generating the third area by mechanically compressing the film using a sealing portion. The third area may advantageously provide another fixing point. The mechanical deformation occurring in the second area may be generated by or during the welding process, which may ultimately weaken the film or may even pierce a film having low elongation properties. Providing mechanical compression at an additional fixing point advantageously allows a film that is not compatible at all and cannot be fixed or integrally bonded to the frame member to be more securely fastened to the frame.

[0016] When the first and / or second frame members include protrusions suitable for mechanically compressing the membrane, the third region may be produced simultaneously with the first and second regions. In such embodiments, the third region may be produced by a simple application of mechanical force, for example when the first, second and optional transition regions are produced by a welding process or during a welding process, such as an ultrasonic welding process, wherein pressure is applied by an ultrasonic welding electrode, which also provides pressure to mechanically compress the membrane in the third region. The third region may not be produced by a welding process or during a welding process, but may be produced by a simple application of mechanical force. Alternatively, when a different third frame member includes a protrusion suitable for mechanically compressing the membrane, the third region may be produced separately from the first and second regions or not at the same time. In such embodiments, for example, when the membrane fixed to the first and second frame members is set in its final system (such as a battery cell stack), the third region may be produced by a simple application of mechanical force. Assembling the final system may include fastening together various components of the system, including the membrane fixed to the first and second frame members, thereby providing a mechanical force to produce mechanical compression in the third region. The simple application of pressure or mechanical force means that no dedicated equipment is required to provide excessive pressure or force. The simple application of pressure or force may be done manually or with the aid of a tool, such as a tightening tool. Assembling the final system may include tightening together the various components of the system, including the membrane secured to the first and second frame members, thereby providing a mechanical force to produce mechanical compression in the third region.

[0017] The fixing area may include a fourth area. Generating the fixing area may also include generating the fourth area. The fourth area may be between the second area and the third area. The method may also include generating the fourth area by mechanically compressing the film using a sealing portion. The sealing portion in the fourth area may be different from the sealing portion in the third area. The fourth area may advantageously provide a further fixing point.

[0018] On the other hand, a cell stack is provided, comprising at least one of the following: a diaphragm fixed between a first frame member and a second frame member, and a pair of electrode assemblies, the diaphragm fixed between the first frame member and the second frame member being arranged between the pair of electrode assemblies. The diaphragm has at least one property that imparts incompatibility and prevents it from being fixed to the first and second frame members. The fixing area of ​​the first frame member, the diaphragm, and the second frame member includes a first area and a second area. The first area includes a first frame member integrally bonded to the second frame member, and the second area includes a diaphragm that is mechanically deformed between the first frame member and the second frame member. The cell stack also includes an electrically isolating end plate in an adjacent layer of each outermost electrode assembly, wherein the layers of the cell stack are fastened together.

[0019] For ease of reference, a membrane (such as a diaphragm) secured between the first frame member, the second frame member, and the optional third frame member is referred to herein as a "membrane sandwich". The membrane sandwich disposed between the pair of electrode assemblies is referred to herein as a "cell". Thus, a cell configured for use in a battery or redox flow battery is a "battery cell". A cell configured for use in hydrogen generation is an electrolyzer cell. A cell configured for use in water deionization is an electrodialysis cell.

[0020] The fixed area of ​​the membrane sandwich includes a first area and a second area. The first area includes a first frame member integrally bonded to a second frame member. The second area includes a diaphragm that is mechanically deformed between the first frame member and the second frame member. In other words, the second area includes a mechanically deformed membrane sandwich.

[0021] As described above, the first region may not include a membrane. The first region may be a double-layer structure including first and second frame members integrally bonded to each other. The diaphragm may be disposed between the first and second frame members only in the second region. Thus, the fixed region of the membrane sandwich may include: the first region is a double-layer structure including first and second frame members integrally bonded to each other; and the second region is a mechanically deformed three-layer structure including a diaphragm sandwiched between the first and second frame members.

[0022] The disclosed cell stack includes at least one cell. The number of cells in the cell stack depends on the required output. For a battery cell stack, the number of cells in the battery cell stack depends on the required energy output. When there is more than one cell, the electrode assembly in a pair of electrode assemblies can be shared with adjacent cells.

[0023] The cell stack further comprises electrically isolating end plates in adjacent layers of each outermost electrode assembly.Thus, the at least one cell is disposed between a pair of electrically isolating end plates.

[0024] The layers of the cell stack are fastened together. The at least one cell and the pair of electrically isolating end plates are fastened together to obtain the cell stack. The fastening of the layers of the cell stack may be performed using simple application of pressure or mechanical force to provide appropriate sealing or fixation of the components of the cell stack.

[0025] In yet another aspect, use of an ion exchange membrane in the disclosed cell stack is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1a The membrane 104 fixed between the first frame member 102 and the second frame member 106 is shown along the line AA' ( Figure 1b ) is an illustration of a cross-sectional view.

[0027] Figure 1b Shown according to Figure 1a FIG. 1 is an illustration of a top view of a membrane 104 secured between a first frame member 102 and a second frame member 106 according to an embodiment of the present invention.

[0028] Figure 2a to Figure 2c A diagram of a sonotrode 200 is shown in accordance with an embodiment of the present disclosure.

[0029] Figure 3a An illustration of a cross-sectional view of the film sandwich 100 along line AA′ is shown, wherein the region 104a where the film 104 is fixed between the first frame member 102 and the second frame member 106 also includes a transition region 104c and a mechanically deformed second region 104d.

[0030] Figure 3b Shown according to Figure 3a 1 is an illustration of a top view of a fixing region of an embodiment of the invention, which fixing region comprises the region 104a, the transition region 104c and the mechanically deformed second region 104d, but is only located at two opposite sides of the membrane 104.

[0031] Figure 4a The film 104 fixed between the first frame member 102 and the second frame member 106 along the line AA′ ( Figure 4b ) is an illustration of a cross-sectional view.

[0032] Figure 4b Shown according to Figure 4a 1 is an illustration of a top view of a membrane 104 secured between a first frame member 102 and a second frame member 106 , wherein a third frame member 110 is configured to mechanically compress the membrane 104 against the first frame member 102 .

[0033] Figure 5 Shown according to Figure 4aAn illustration of a cross-sectional view of a film interlayer 100 of an embodiment of FIG. 1 , wherein the third frame member 110 includes an edge chamfer at an edge of the frame member 110 .

[0034] Figure 6a Shown according to Figure 4a 1 is an illustration of a cross-sectional view of a membrane sandwich 100 of an embodiment of the invention, wherein the third frame member 110 is configured to mechanically compress the membrane 104 against the first frame member 102 via the second frame member 106 .

[0035] Figure 6b Shown according to Figure 6a FIG. 1 is an illustration of a film interlayer 100 that is mechanically deformed upon application of a mechanical force due to protrusions of a frame member 110 according to an embodiment of FIG.

[0036] Figure 7a An illustration of a cross-sectional view of a membrane 104 fixed between frame members according to another embodiment of the present disclosure is shown, wherein the fixing region 108 includes a first region 102a, a second region 104a, a third region 104e, and a fourth region 104f.

[0037] Figure 7b Shown according to Figure 7a An illustration of an alternative gasket providing mechanical compression in the fourth region 104f of an embodiment.

[0038] Figure 7c Shows Figure 7a FIG. 1 is a diagram of another embodiment of a fourth region 104 f.

[0039] Figure 8 An illustration of a cross-sectional view of a battery cell stack 300 is shown in accordance with an embodiment of the present disclosure.

[0040] In the drawings, like reference numerals denote like parts. DETAILED DESCRIPTION

[0041] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the attached drawings. A detailed description of the present invention will be provided for the purpose of explaining the principles of the present invention and its practical application, thereby allowing those skilled in the art to understand the various exemplary embodiments of the present invention and various modifications suitable for the specific purposes contemplated. The detailed description is not intended to be exhaustive or to limit the present invention to the precise embodiments disclosed. Modifications and equivalents will be apparent to those skilled in the art and are encompassed within the spirit and scope of the appended claims.

[0042] A method of securing a membrane between a first frame member and a second frame member is provided.

[0043] "Frame" refers to a structure that circumferentially holds or surrounds the membrane disclosed in this article. A frame member is a part of a frame that cooperates with other frame members to circumferentially hold or surround the membrane. For example, a frame member can be a cross-sectional half of a frame, and another frame member is another cross-sectional half of a frame, wherein two cross-sectional halves clamp the membrane. The frame can include different parts that perform different functions to circumferentially hold or surround the membrane. The frame can include a frame portion that forms a structure of the frame, i.e., a structural frame portion. The structural frame portion can have a certain hardness that gives the structure to the frame or the final system. The frame portion can also be implemented as a film or foil with a relatively small thickness, so that the stacked units of multiple membrane sandwiches can be assembled with a small spacing relative to each other. The film or foil can have at least one attribute that gives compatibility and cannot be fixed or integrally bonded to another frame member. A frame member with a thinner, non-structural frame portion allows filling any space between the structural frame members. The filled space advantageously prevents or reduces electrolyte leakage into the environment through the space. The filled space also advantageously prevents or reduces stress on a layer (such as a membrane), which may be caused by pressure from assembly and / or operation. The frame may include a sealing portion that strengthens the structure of holding the membrane to the frame. The sealing portion may also allow any space between the frame portion or frame members to be filled. The sealing portion may be a sealing material (such as glue, gasket or other sealing materials disclosed herein), a film or foil that may be implemented as a sealing material, or a filling material (such as foam, felt or other woven or non-woven materials). The frame may include a part of the system where the membrane sandwich is located (if the system is a unit stack, such as an electrode assembly). When the system is a unit stack, the two frame members cannot both be electrode assemblies, because the integral combination of the two electrode assemblies will produce a short circuit. Therefore, the first frame member and the second frame member may each be selected from: a frame portion, a sealing portion or a frame compatible film, or an electrode assembly forming the structure of the frame, as long as the two frame members are not both electrode assemblies. In an embodiment, the first frame member is a frame portion, and the second frame member is a frame compatible film.

[0044] The frame or frame member can be made of synthetic or natural polymer materials (such as plastic or rubber) or other non-conductive materials. When the membrane interlayer is used in a battery cell, a fuel cell or the like, the frame can provide the required isolation to prevent short circuits. The frame or frame member can be made of thermoplastic polymers. Non-limiting examples of thermoplastic materials include nylon, polyethylene, polypropylene, polyester, polyamine, poly(ether ether ketone) (PEEK) or a combination thereof. In an embodiment, the frame member is made of polypropylene. In an embodiment, both the first and second frame members are made of polypropylene.

[0045] The membrane can be made of a polymer material or a mixture of polymers or monomers; a ceramic composite material; a metal or a metal alloy; or a combination thereof. The material of the membrane and the material of the frame member can be arbitrarily selected, as long as the membrane and the frame member are not compatible at all and cannot be fixed or integrally combined with each other. As an example, the membrane includes a polymer material, wherein poly(ether ether ketone) (PEEK) exists as part or as a substitute for the polymer backbone, and the frame member is made of polypropylene. As another example, the membrane includes a polymer material, wherein polytetrafluoroethylene (PTFE) exists as part or as a substitute for the polymer backbone, and the frame member is made of polypropylene. The membrane can be or can be used as a diaphragm or an ion exchange membrane. When the membrane is an ion exchange membrane, the membrane may include a polymer mixture exhibiting acidic groups and basic groups. The membrane may include a polymer mixture exhibiting acidic groups and basic groups, wherein PEEK exists as part or as a substitute for the polymer backbone of the polymer mixture.

[0046] The membrane of the unit is the core component of the battery unit, fuel cell or the like. The main task of the membrane is to separate the electrolyte with positive and negative charge and to conduct ions selectively through the membrane, which is necessary for the conduction of electrons via an external circuit, so it is called "ion exchange membrane". Another task of the membrane such as a fuel cell is to be used for humidification, because the current generated by the electrochemical reaction in the fuel cell uses a supply air rich in moisture. This membrane is a gas-gas membrane that is permeable to water vapor but impermeable to other gaseous components in the air. The term "membrane" also covers this gas-gas membrane. In addition to good electrochemical properties (such as high ion conductivity and low resistance), the membrane should have excellent mechanical and chemical stability, as well as low water absorption and expansion behavior. In addition, the membrane should have good processing properties, such as manipulation and connection with other materials by welding or bonding. Finally, the battery or fuel cell with the membrane should show high cycle stability, high energy efficiency and high coulomb efficiency of the whole system. As can be seen, the material of the membrane and its system has many requirements. It may be difficult to achieve all requirements, therefore, the present disclosure provides advantages when material incompatibility is inevitable.

[0047] The membrane can be a single layer configuration or a multilayer configuration. In the case of a multilayer configuration, for example, there are three membranes placed next to each other, wherein the central membrane is a functional membrane or a membrane providing the main function of molecular, ionic or other particle exchange, and the outer membranes each form a cover or support membrane.

[0048] The method includes creating a fixed region including a first region and a second region, wherein creating the first region includes integrally bonding a first frame member to a second frame member, and wherein creating the second region includes mechanically deforming a membrane between the first frame member and the second frame member.

[0049] By "integrally bonded," it is meant that two separate objects are joined at their point of connection into a single, unitary structure. Integrally bonded includes material bonding in which the materials of the two separate objects are fused or coalesced at their point of connection, for example, by the application of heat and / or pressure. Examples of integral bonding include welding. Integrally bonded is contrasted with adhesive bonding because adhesive bonding may involve an integral bond between the adhesive and the material in contact with the adhesive, but not between the materials of the two separate objects.

[0050] By "mechanically deformable", it is meant that the three-layer structure bends or deforms and can retain its deformed shape. To bend or deform, each layer preferably has appropriate elongation properties during the mechanical deformation step to prevent rupture. When a layer does not have appropriate elongation properties, then the layer may be punctured, ruptured or punched during the mechanical deformation step. The three-layer structure can be deformed to obtain a three-dimensional shape, different from its initial layered, linear form. Figure 6b , an illustration of a mechanical deformation layer in a third region is shown, wherein the mechanical deformation is produced by a protrusion of the third frame member 110. The mechanical deformation may be similar to the embossing of the film. The mechanical deformation of the film sandwich may cause the film and one of the first and / or second frame members to have a similar deformed shape. The mechanical deformation of the film sandwich may cause the three layers to have similar shapes. The mechanical deformation layer may have geometric shapes that complement each other. The mechanical deformation layer may be form-fitting. The mechanical deformation film may be configured to engage one or two frame members for fixation in at least a form-fitting and / or force-fitting manner. The mechanical deformation layer may have a complementary form-fitting profile, such as a profile formed as a vertically extending form-fitting groove or a form-fitting protrusion. The three-layer structure may be mechanically deformed in a form-fitting and / or force-fitting manner (e.g., by screwing, latching and / or clamping).

[0051] The film may have at least one property that imparts incompatibility and cannot be fixed to the first and second frame members. When the fixing or bonding method includes an integral bonding process (such as a welding process), the property that imparts incompatibility includes a melting point. Since the welding process involves the melting of the object to be bonded, an object with a higher melting point than another object to be bonded may not melt or not melt sufficiently to allow fusion or agglomeration of the objects to occur. The difference in melting point may be 100°C or higher, 130°C or higher, 150°C or higher, 180°C or higher, or 200°C or higher. Additionally or alternatively, the property that imparts incompatibility includes being made of a material different from the frame member. An example of different materials is that the film is a ceramic composite material and the frame member is a polymer. Another example is that the film is a polymer, and the polymer backbone of the film may be different from the polymer that constitutes the frame member. The film is made of a material different from the material of the frame member and may impart fundamental incompatibility and cannot be fixed or integrally bonded to the frame member. Being made of different materials may also indicate that the melting points of the materials are different. For example, the melting point of polyamides may be above 200°C, whereas the melting point of polyolefins is generally below 200°C.

[0052] Figure 1a The film 104 according to an embodiment of the present disclosure is shown along line AA' ( Figure 1b ), a cross-sectional view of a membrane 104 is fixed between a first frame member 102 and a second frame member 106, ie, a membrane sandwich 100. Figure 1b Shown according to Figure 1a FIG. 1 is a diagram of a top view of a membrane 104 of an embodiment of the present invention, wherein the membrane 104 is fixed to a first frame member 102 ( Figure 1b (obstructed in the middle) and between the second frame member 106.

[0053] The membrane 104, the first frame member 102 and the second frame member 106 are as disclosed herein. The fixing area 108 includes the first area 102a and the second area 104a. The first area 102a includes the first frame member 102 integrally bonded to the second frame member 106. The second area 104a includes a mechanically deformed membrane sandwich. The mechanical deformation in the second area is not shown in the figure, but it can be seen from Figure 1a It can be seen that the first region 102 a is a two-layer structure including the first frame member 102 and the second frame member 106 , while the second region 104 a is a three-layer structure including the film 104 sandwiched between the first frame member 102 and the second frame member 106 .

[0054] If you can Figure 1a and 1bAs seen in FIG. 1 , the frame members 102, 106 (collectively referred to as the "frame") hold the membrane 104 around its perimeter. The frame allows the middle 104b of the membrane 104 to be exposed so that it can perform its function, such as the exchange of molecules, ions or other particles. The functional surface area or active surface area (104b) of the membrane 104 depends on the requirements of the final system (such as the battery cell stack disclosed herein). Therefore, the surface area of ​​the membrane 104 sandwiched between the frame members 102, 106 also depends on the requirements of the final system.

[0055] The surface area or width w of one side of the frame can be completely used as the fixing area 108, such as Figure 1a As shown in . When the fixing or bonding method includes a welding process, the entire width w of one side of such a frame or frame member can be subjected to the temperature and pressure of a welding tool (e.g., an ultrasonic welding electrode). When the first region 102a and the second region 104a are produced by or during a welding process, the entire width w of one side of such a frame or frame member can be subjected to the temperature and pressure of a welding tool (e.g., an ultrasonic welding electrode). Therefore, the first region 102a can be close to the first edge 102' of the frame members 102, 106. Alternatively, there may be a space or width between the first edges 102' before the first region 102a begins. That is, the width w of the frame member may not correspond to the width of the fixing region 108, and the width w of the frame member may be greater than the width of the fixing region 108. See Figure 1b , the widths of the fixing regions 108 on all sides of the frame may correspond to each other or may not correspond to each other. For example, the widths of two opposite sides of the fixing region 108 may be the same as each other, but different from the other two sides of the fixing region.

[0056] The width w of frame member 102 may or may not correspond to the width w of frame member 106. Figure 1a , the widths w of both frame member 102 and frame member 106 are shown to correspond to each other.

[0057] The thickness t of the frame member depends on the selection or type of the frame member. For example, when the frame member 102 is a structural frame part and the frame member 106 is a film, the thickness t of the frame member 102 can be thicker than the thickness of the frame member 106. As an example, the range of the thickness t suitable for the film is from about 10 microns to about 1000 microns, or from about 50 microns to about 1000 microns, or from about 100 microns to about 1000 microns, or from about 10 microns to about 500 microns, or from about 10 microns to about 300 microns, or from about 10 microns to about 200 microns, or from about 100 microns to about 200 microns. In an example, the thickness t suitable for the film is about 150 microns. When the frame member 106 is a polypropylene film, the range of the thickness t of this frame member 106 can be similarly from about 10 microns to about 1000 microns, for example 150 microns. The range of the thickness t of the structural frame member 102 can be from about 0.2mm to about 10mm, for example about 1 to 2mm.

[0058] like Figure 1a 4 , the film 104 is not present in the first region 102a. The film 104 is disposed between the first frame member 102 and the second frame member 106 in the second region 104a. The second region 104a is adjacent to the first region 102a. An edge 104' of the film 104 may mark the beginning of the second region 104a. A second edge 102" of the frame members 102, 106 may mark the end of the second region 104a. When the second edges 102" of the frame members 102, 106 do not correspond to each other, the end of the second region 104a may be marked by the edge 102" of the shorter frame member (such as shown in FIG. 4 ) because the second region 104a is a three-layer structure. As shown in FIG. Figure 1a In the example of the embodiment in FIG. 1 , the total width w of the frame members is 12 mm, and the length of the film 104 disposed between the first frame member 102 and the second frame member 106 is 7 mm, so the width of the first region 102a is 5 mm, and the width of the second region 104a is 7 mm. It should be noted that the figures are not drawn to scale.

[0059] The disclosed method may include simultaneously producing the first region 102a and producing the second region 104a. The step of simultaneously producing the first region 102a and the second region 104a may include a welding process. The welding process may include contacting a welding tool on the first region 102a and the second region 104a. The contact surface of the welding tool may have a size corresponding to or complementary to the first region 102a and the second region 104a so as to produce the first region 102a and the second region 104a. The step of contacting the welding tool on the regions 102a, 104a may be performed under a set of conditions. The set of conditions may include a pressure setting or a sequence of ramping up and / or ramping down of a pressure setting, a pressure setting or a duration of a pressure ramp, a force setting or a sequence of ramping up and / or ramping down of a force setting, a force setting or a duration of a force ramp, a temperature setting or a sequence of ramping up and / or ramping down of a temperature setting, a temperature setting or a duration of a temperature ramp setting, a setting of a welding depth or welding stroke, a sequence of ramping up and / or ramping down of a welding depth and welding stroke, a setting of a welding depth or welding stroke or a duration of a ramp, other parameters required to define a reliable welding process, or a combination thereof. When the welding process is an ultrasonic welding process, the set of conditions may also include an amplitude setting, a frequency setting, a vibration setting, a sequence of ramping up and / or ramping down thereof, a duration thereof, or a combination thereof.

[0060] When the welding process is an ultrasonic welding process, the welding tool may be a sonotrode. FIG. 2 shows an illustration of a sonotrode 200 according to an embodiment of the present disclosure. The sonotrode 200 may include a first region 202a and a second region 204a. The first region 202a may be complementary to the first region 102a to produce the first region 102a. The second region 204a may be complementary to the second region 104a to produce the second region 104a.

[0061] The second zone 204a may have a projection of a shape configured to mechanically deform the three-layer structure in the second zone 104a. The film sandwich may be mechanically deformed at multiple points according to the shape of the projection of the second zone 204a. The shape of the projection of the second zone 204a may be adjusted according to the properties of the film. In an embodiment, the shape of the projection of the second zone 204a may be adjusted according to the elongation properties of the film 104 used or according to the reaction of the film in its environment. The height of the projection may correspond to or match the thickness of the three-layer structure in the second zone 104a. Since the film 104 may be relatively thin compared to the frame members 102, 106, the height of the projection in the first zone 202a may also be similar or the same. The welding tool first contacts the frame member, such as the second frame member 106 (which may not be as sensitive to the contact surface of the welding tool as the film 104 in terms of tearing), then contacts the film 104, and finally contacts other frame members, such as the first frame member 102, thereby providing a film sandwich that is mechanically deformed according to the shape of the projection of the second zone 204a. The welding tool may mechanically deform the frame member it contacts first, through which it also mechanically deforms the membrane. The welding tool may also mechanically deform the last frame member, but this may or may not occur, depending on the hardness of the frame member and / or welding conditions.

[0062] For films with relatively high elongation properties or films that do not react adversely in their environment, the contact surface of the welding tool (such as a sonotrode) may include a well-defined edge, such as Figure 2a and 2b If the membrane does not have sufficient elongation properties, a clear or sharp edge may tear or puncture or otherwise weaken the membrane, resulting in undesirable leakage in the operating environment. Relatively high elongation properties are, for example, elongation percentages of 10%, 25%, 50%, 75%, 100%, 110%, 120% or more. For example, for PTFE-based polymer membranes, membranes that do not exhibit any significant response to changes in humidity in their environment, and / or membranes that tend only to expand and not contract in their environment, the contact surface of a welding tool (such as an ultrasonic welding electrode) may include pyramids (such as on its contact surface) Figure 2a in) or a truncated pyramid (such as in Figure 2b middle).

[0063] For films with lower elongation properties or films that tend to cycle between physical states in their environment (such as shrinking and expanding due to, for example, humidity fluctuations in the storage environment or the operating environment), the contact surface of the welding tool (such as a sonotrode) can include rounded corners or smooth surfaces, such as Figure 2cAs shown in . The contact surface of the welding tool may not include clear or sharp edges. Other types of rounded surfaces include chamfers or other harmonious geometries. The welding conditions for such a membrane may not be as harsh as the welding conditions for a membrane with relatively high elongation properties or a membrane that does not react adversely in its environment. Relatively low elongation properties are, for example, elongation percentages of less than 10%, 8%, less than 8%, 5%, or less than 5%. When the disclosed fixing area includes a third area and / or a fourth area, the welding process can be advantageously carried out with fewer restrictions. For example, even if the membrane has lower elongation properties or tends to cycle between physical states in its environment, the contact surface of a welding tool (such as an ultrasonic welding electrode) can also include clear edges. Advantageously, even if the membrane is pierced during welding, the third area and / or the fourth area can prevent or at least minimize undesirable leakage.

[0064] The first zone 202a may be adapted to integrally bond the double-layer structure in the first region 102a. The contact surface of the first zone 202a may be adapted to provide sufficient contact during the welding process. Sufficient contact may be provided by protrusions. For convenience and / or economy, the first zone 202a may have protrusions similar to those of the second zone 204a. As described above, the frame members 102, 106 in the first region 102a may be less sensitive to the surface structure of the welding tool, which means that the frame members 102, 106 may not be easily damaged by the choice of the surface structure of the welding tool. Therefore, the shape requirements of the protrusions of the first zone 202a may not need to be as clear as those of the second zone 204a. In the example, the shape of the protrusions of the first zone 202a may be arbitrarily selected or adjusted according to the convenience and / or economy of manufacturing the welding tool, or may follow the shape of the protrusions of the second zone 204a. Therefore, the first zone 202a is Figures 2a to 2c 204a is shown as being the same as in the second zone 204a.

[0065] The disclosed method may include creating a transition region in the second region, wherein integral bonding occurs in the transition region. Figure 3a It shows that along line AA'( Figure 3b 104a, wherein the region 104a in which the membrane 104 is fixed between the first frame member 102 and the second frame member 106 also includes a transition region 104c and a mechanical deformation second region 104d. The transition region 104c may be adjacent to the first region 102a. As described above, the edge 104' of the membrane 104 may mark the beginning of the region 104a, in particular the transition region 104c. The second edge 102" of the frame members 102, 106 may mark the end of the region 104a, in particular the end of the mechanical deformation second region 104d.

[0066] Thus, the welding process may also include contacting a welding tool (such as also in the first region 102a, the transition region 104c, and the second region 104d) at the first region 102a, the transition region 104c, and the second region 104d. Figure 3a 2. The contact surface of the welding tool 200 may have a size corresponding to or complementary to the first region 102a, the transition region 104c, and the second region 104d. Similar to the above, the welding tool 200 may include a first region 202a, a transition region 204c, and a second region 204d that are complementary to the first region 102a, the transition region 104c, and the second region 104d, respectively.

[0067] In an embodiment, since the first region 202a of the welding tool may be similarly adapted to integrally bond the two-layer structure in the first region 102a, the transition region 204c of the welding tool 200 may be similar or identical to the first region 202a. Since the film 104 is not compatible at all and cannot be welded to the first and second frame members 102, 106, it is necessary to destroy the film 104 in order to provide an integral bond in the transition region 104c. Therefore, the shape of the protrusion of the transition region 204c may be adjusted according to the properties of the film 104. Unlike the second region 104d where care must be taken to mechanically deform the film without destroying the film, the contact surface of the transition region 204c and / or the first region 202a of the welding tool 200 may include a clear or sharp edge, such as Figure 2a The pyramid shown or Figure 2b Here, in Figure 3a , the contact surfaces of the transition zone 204c and the first zone 202a of the welding tool 200 include pyramids. A well-defined edge can advantageously pierce the membrane 104 in the transition region 104c, thereby allowing the first and second frame members 102, 106 to be integrally bonded together through the pierced membrane 104. For membranes with lower elongation properties or membranes that tend to cycle between physical states in their environment, considerations for the second zone 104d remain as described above. Therefore, the shape of the protrusions of the welding tool 200 in the transition zone 204c and / or the first zone 202a can be different from the second zone 204d. Figure 3a As shown in FIG. 1 , the ultrasonic welding electrode 200 includes a first zone 202a complementary to the first zone 102a and a transition zone 204c complementary to the transition zone 104c. The first zone 202a and the transition zone 204c have protrusions of a shape configured to pierce the film 104 in the transition zone 104c, such as a triangle. Since the first zone 202a and the transition zone 204c can have protrusions of the same shape, such a zone on the welding tool can be simply referred to as a "first zone". The second zone 204d is complementary to the second zone 104d. The second zone 204d has protrusions of a shape configured to mechanically deform the film 104 in the second zone 104d, such as a triangle. Figure 3a The rounded surface of the protrusion in 204d is shown.

[0068] Thus, the first region, the transition region and the second region of the fixing region can be produced simultaneously, for example by or during a welding process.

[0069] The first region, the second region and the optional transition region can be produced at least at two sides of the film, for example at two opposite sides of the film, by or during a welding process. The fixing region comprising the first region, the second region and the optional transition region can be produced at two, three or all sides of the film. Figure 3b , a fixing region 108 including a first region 102a, a mechanically deformed second region 104d, and a transition region 104c may be produced at two opposite sides of the membrane 104. In such an embodiment, the width w1 of the fixing regions 108 on both sides may be the same, and may be the same as or different from the width w2 of the fixing regions 108 on the other two sides. The fixing regions on the other two sides may include mechanical fixing, for example, without involving a welding process. That is, the first region 102a and the second region 104a may not exist on some sides, but the fixing regions on all sides may include mechanical fixing, for example, the third region 104e described below. When the frame member (102 or 106) is a thin film or foil, Figure 3b Embodiments of the disclosed method may be useful. The film or foil may be provided as a roll of film or foil, or may even be provided as a roll comprising the film and the film or foil. The welding process may be performed after unrolling the roll onto the structural frame member. Advantageously, the processing speed of the disclosed method may be increased and the number of steps in the welding process may be reduced.

[0070] The disclosed method may include creating a third region in which mechanical compression of the film occurs by a projection or sealing portion of the frame member. "Mechanical compression" refers to a form of mechanical fixation that is gentler than mechanical deformation. Mechanical compression may involve the provision of a mechanical force (such as by clamping) to cause the film to remain stationary between the frame members. Mechanical compression may not cause mechanical deformation, but in some embodiments, the mechanical force used may be high enough to cause mechanical deformation. Mechanical compression in the third region may exist on all sides of the film.

[0071] In an embodiment, the disclosed method may include producing a third region in which mechanical compression of the film occurs by a sealing portion (not shown) rather than a projection of a frame member. The sealing portion may mechanically compress the film directly or indirectly against the relative frame member, as described herein. The sealing portion may be a sealing portion as disclosed herein, such as a sealing material, such as a solid gasket. In order to accommodate the sealing portion, the second edge 102 "of one of the frame members 102, 106 may be shorter than the other. The sealing portion may be arranged close to the second edge in the third region. The sealing portion may be arranged between the second edge 102 "of the shorter frame member and the center of the film 104b in the third region. When the third frame member exists and is stacked adjacent to the frame member 102 or 106, the third frame member may include a corresponding groove to accommodate the sealing portion. The gasket may be held in place by a groove. The gasket may be held in place by glue, or may be overmolded to the frame member. The sealing portion may mechanically compress the film on one surface of the film or on both surfaces of the film. Each sealing portion may be held in place by a groove or glue of the relevant frame member, or may be overmolded to the relevant frame member.

[0072] In an embodiment, the disclosed method may include creating a third region in which mechanical compression of the membrane occurs through a protrusion of the frame member. The frame member including the protrusion may be the first frame member 102 or the second frame member 106 or the third frame member 110 ( Figure 4a and 4b ). When the protrusion is included on the first frame member 102 or the second frame member 106, the membrane can be mechanically compressed between the first frame member and the second frame member in the third region. When the protrusion is included on the third frame member 110, the membrane can be mechanically compressed between the third frame member 110 and the frame members 102, 106 on the opposite side of the membrane 104 in the third region to clamp the membrane 104.

[0073] Figure 4a The film 104 according to an embodiment of the present disclosure is shown along line AA' ( Figure 4b ), a cross-sectional view of a membrane 104 is fixed between a first frame member 102 and a second frame member 106, ie, a membrane sandwich 100. Figure 4b Shown according to Figure 4a108, the membrane 104 is secured between a first frame member 102 and a second frame member 106 (both obscured by a third frame member 110), wherein the third frame member 110 is configured to mechanically compress the membrane 104 against the first frame member 102. The surface area or width w of one side of the frame is again fully utilized as the securing area 108, however, only a portion of the width of the frame is used for the welding process, and the remaining width is used for mechanical compression in the third area.

[0074] The fixing region 108 according to this embodiment includes a first region 102a, a transition region 104c, a mechanical deformation second region 104d and a third region 104e. Figure 4a and 4b In the embodiment, the third region 104e is produced by a protrusion of a different frame member (frame member 110). The different frame member may be a structural frame portion. When the first frame member 102 or the second frame member 106 is a film, a sealing portion, or is otherwise thinner than the structural frame portion, it may be useful to provide a protrusion on the different frame member. The third region (such as 104e) may not be produced by or during the welding process. The third region may not be formed by the welding process. Therefore, such a protrusion is provided on the frame member, rather than on the welding tool, so as to mechanically compress the membrane but not necessarily deform the membrane. This is in Figure 4a , where the sonotrode 200 has dimensions corresponding only to the first region 102a, the transition region 104c and the mechanically deformed second region 104d. The third region 104e may be produced separately from the first region 102a, the transition region 104c and the second region 104d or not at the same time. The third region 104e may be produced by fastening components of the system in which the film sandwich 100 is finally assembled, wherein mechanical forces are applied to fasten the components together.

[0075] Alternatively, the third region 104e may be created by a protrusion of the frame member 102 or the frame member 106. In such an embodiment, the protrusion 104e (not shown) may be included on the longer frame member 102, 106 (such as Figure 4a The frame members 102 in the welding process are brought together, so during the welding process, the protrusions 104e can be caused to mechanically compress the membrane 104 simultaneously with the creation of the region.

[0076] The protrusion of the frame member (such as frame member 110) may have a shape configured to mechanically compress the film 104 in the third region 104e. The shape may not be particularly limited. The shape may be a shape disclosed herein, such as a shape with a clear edge (such as a pyramid or a truncated pyramid), or a shape with a rounded corner or a smooth surface (such as a rounded cone), a curved edge, or a chamfer with an appropriate radius. A specific example of a rounded protrusion is an edge chamfer at the edge of the frame member 110, Figure 5 Shown in. Figure 5 The edge chamfer of the frame member 106 has a radius or curvature corresponding to the thickness of the frame member 106, so that the film 104 can be properly mechanically compressed. The edge of the frame member close to the third region can have a protrusion with a corresponding fillet. The shape can be adjusted according to the properties of the film 104 used (such as the creep tendency, stiffness or elongation performance of the film) or according to the reaction of the film in its environment, as described above. The frame member may have one or more protrusions. The protrusion may extend along the boundary of the frame member. The protrusion may be arranged at regular intervals along the boundary of the frame member. The protrusion may be arranged on all sides of the film. When the first region, the second region and the optional transition region produced by the welding process are produced at both sides of the film or not all sides of the film, the remaining sides of the film can be fixed to the frame member by the protrusion. The remaining sides of the film can be mechanically fixed by the protrusion of the frame member, specifically mechanically compressed. The third region can approach the second edge of the frame member 102,106,110 opposite to the first edge 102'. The second edge of the frame member is represented in the figure as ("). For example, the second edge of the frame member 110 closer to the center of the membrane 104b is 110". Providing a third region close to the second edge can advantageously disperse the fixing points throughout the width of the frame. Mechanical compression in the third region can advantageously relieve the membrane from being weakened during embossing through the welding process, because depending on the properties of the membrane, embossing can adversely affect the tear resistance of the membrane, which may ultimately tear at the embossed points.

[0077] The protrusions on the frame member can directly mechanically compress the membrane against the opposing frame member, such as Figure 4a As shown in . The protrusions on the frame members can mechanically compress the membrane without any intermediate layer between them. Alternatively, the protrusions on the frame members can indirectly mechanically compress the membrane against the opposing frame members, such as Figure 6a When the intermediate layer (such as here the frame member 106) is a film, a sealing portion or otherwise mechanically compressible or even deformable without the use of any heat and / or pressure, Figure 6aEmbodiments of may be useful. There may be more than one intermediate layer, such as a membrane and a sealing portion (e.g., a gasket). The protrusion on the third frame member may optionally mechanically deform such an intermediate layer, through which it also mechanically deforms the membrane against the opposing frame member.

[0078] The height of the protrusions can be adjusted so that mechanical compression of the membrane 104 can penetrate any other layer ( Figure 4a ) or through any other layer ( Figure 6a ) (such as frame member 106) occurs. In general, the layers of the frame member and the protrusions can be designed in a zero-gap direction.

[0079] exist Figure 6b FIG. 1 is a diagram of a film sandwich 100 that is mechanically deformed due to the protrusions of the frame member 110 when a mechanical force is applied. It can be seen that the protrusions of the frame member 110 are mechanically compressed and deformed according to the shape of the protrusions. Figure 6b In a specific embodiment of the present invention, the frame member 106 and the membrane 104 are additionally deformed. Depending on the height of the protrusion, the protrusion can also produce a mechanical deformation of the frame member 102 according to its shape. Figure 6b 1 shows that the protrusions of frame member 110 create indentations in frame member 102 (as opposed to similar shapes of protrusions) because the height of the protrusions does not extend beyond the thickness t of frame member 102. Frame member 106, membrane 104, and frame member 102 have suitable yield properties during the mechanical compression step to be compressed and even deformed without breaking. Although not shown in the figure, the mechanical deformation in the second region can be visualized, similar to Figure 6b Illustration of the mechanical deformation in the third region.

[0080] The fixing area 108 of the embodiment in Figures 4 to 6 includes a first area 102a, a second area 104a (which may include a transition area 104c and a mechanical deformation second area 104d) and a third area 104e. In some embodiments, the area generated by the welding process or generated during the welding process can be separated from the mechanical compression area 104e. The separation can be performed by a fixing method as disclosed herein. The area generated by the welding process or generated during the welding process can be separated from the mechanical compression area 104e by a fourth area. Therefore, the fixing area can include the fourth area. Advantageously, the fourth area provides another fixing point, thereby increasing the maximum pressure that the final system can withstand before an undesirable leak occurs. Figure 7aA diagram of a fixing region 108 is shown, which includes a first region 102a, a second region 104a (which may include a transition region 104c and a mechanically deformed second region 104d), a third region 104e, and a fourth region 104f. Because the region created by or during the welding process is separated from region 104e by the fourth region 104f, the second edge 102" of one of the frame members 102, 106 is shorter than the other in order to accommodate the fourth region 104f. The end of the second region 104a is formed by the shorter frame member (i.e., Figure 7a Thus, the shorter frame member (ie, frame member 106) in the region created by or during the welding process is adjacent to the fourth region 104f.

[0081] The fixing method of the fourth region 104f may include integral bonding, mechanical deformation, or mechanical compression. In an embodiment, the fourth region 104f may include mechanical compression. The disclosed method may also include generating the fourth region 104f by mechanically compressing the membrane 104 using the sealing portion 112. The sealing portion 112 abuts against the relative frame member (i.e., Figure 7a The frame member 102 in the fourth region 104f) mechanically compresses the membrane 104. The sealing portion 112 can mechanically compress the membrane 104 directly against the relative frame member or indirectly against the relative frame member through an intermediate layer, as described herein. The sealing portion 112 can be a sealing portion as disclosed herein, such as a sealing material. For example, the membrane 104 can be mechanically compressed in the fourth region 104f by a solid gasket. The mechanical compression in the fourth region 104f can exist on all sides of the membrane. For example, the solid gasket can be a hollow ring or quadrilateral that circumferentially surrounds the membrane at the fourth region 104f. The solid gasket can be a solid gasket commonly used in the art, such as a rubber gasket. The solid gasket may or may not include a profile that increases or enhances the seal or compression in the fourth region 104f. For example, Figure 7b The gasket shown in FIG. 1 includes a profile having bumps on an outer surface.

[0082] In order for the fourth region 104f to separate the welding region from the mechanical compression region, the sealing portion 112 may be located between the protrusions in the second region 104a and the third region 104e. The sealing portion 112 in the fourth region 104f may have a certain thickness t. When the protrusion is included on the third frame member 110, as shown in FIG. Figure 7a As in the embodiment of the present invention, the sealing portion 112 may be located between the edge 102″ and the protrusion of the shorter frame member 102 or 106. When the thickness t of the sealing member 112 is greater than the adjacent frame member (i.e., the region created by or during the welding process) Figure 7aWhen the projection is included on the first or second frame member 102, 106, the sealing member 112 may be received in a corresponding groove (not shown) on the third frame member 110. When the projection is included on the first or second frame member 102, 106, the sealing member 112 may be received in a groove in the first or second frame member 102, 106, between the second region 104a and the projection.

[0083] The sealing portion 112 can mechanically compress the membrane 104 against the opposing frame member on one surface of the membrane 104, such as Figure 7a As shown in FIG. The sealing portion 112 can mechanically compress the film 104 on each surface of the film 104. Figure 7c As shown in FIG. 1 , a sealing portion 112 mechanically compresses the top surface of the membrane 104, and another sealing portion 112 mechanically compresses the bottom surface of the membrane 104. When desired, each sealing portion 112 can be accommodated in an associated frame member (such as Figure 7c The plurality of frames are preferably arranged in grooves of the frame members 102 in the frame members so as to maintain the layers of the frame members at zero gap or as close to zero gap as possible.

[0084] The disclosed method is useful for the assembly of ion exchange membranes in electrochemical process systems, such as in electrolyzers for hydrogen production or electrodialysis cells for water deionization. The disclosed method is useful for the assembly of battery cell stacks. The system to which the fixed membrane is ultimately assembled can be a cell stack, such as a battery cell stack, an electrolyzer cell stack, or an electrodialysis cell stack. The following refers to a battery cell stack, but an electrolyzer cell stack or an electrodialysis cell stack can be similarly constructed.

[0085] A battery cell refers to the smallest unit of a battery for storing and / or converting energy, which includes a positive electrode, a negative electrode, an electrolyte and a separator. The separator electrically separates the positive electrode and its electrolyte from the negative electrode and its electrolyte while ensuring ion transport between them. A battery cell can be a unit of a flow battery or a redox flow battery. In a flow battery, the separator is a non-porous membrane that only allows ions or electrons to pass through. When the separator only allows ions to pass through, the separator is an ion exchange membrane. A single unit can provide about 1 volt of energy. Depending on the requirements, a single unit or more than one unit can be stacked with other layers to form an operational battery cell stack. Because an operational battery requires a stack of layers, the disclosed method of fixing the layers together is advantageous, especially when the separator is not compatible at all and cannot be fixed or integrally bonded to its frame.

[0086] Figure 8 A diagram showing a cross-sectional view of a battery cell stack 300 according to an embodiment of the present disclosure is shown. For clarity, Figure 8 Only one example of each layer is referenced by a reference numeral. A battery cell stack includes at least one membrane interlayer disposed between a pair of electrode assemblies. Figure 8Two membrane interlayers 100 are shown. Each membrane interlayer 100 is disposed between a pair of electrode assemblies 120. One of the electrode assemblies 120 is shared by the two membrane interlayers 100. The electrode assemblies adjacent to the two cells may be shared by the two cells.

[0087] Each electrode assembly 120 may include a positive electrode or a negative electrode or a bipolar plate. For a flow battery, during discharge or operation, the positive electrode is the cathode and the negative electrode is the anode, while during charging, the positive electrode is the anode and the negative electrode is the cathode. The electrode assembly 120 may also include a current collector. For example, the anode may include an anode current collector and an anode active material, while the cathode may include a cathode current collector and a cathode active material. The anode current collector may include a metal such as copper or the like. The cathode current collector may include a conductive metal such as aluminum or the like. The anode active material, the cathode active material, and the current collector may include any number of different conventional and / or proprietary materials. The current collector may be brought into close contact with the active material to increase the battery output. The current collector may secure the active material in its proper position in the stack, thereby extending the life of the battery.

[0088] Here, the frame member 106 is a polypropylene foil, which not only reduces the thickness of the entire stack, but also allows the sealed stacking of the layers (such as frame members 102 and 110). Therefore, the frame of the battery cell stack holds the electrolyte in the frame space, between the pair of electrode assemblies 120, and around the active area 104b of the membrane 104 in a flow-tight manner without leakage or with slight leakage. Any other space can be filled with a sealing material (such as a thermosetting polymer, such as an epoxy resin, or other types of glue or solid gaskets) to prevent or reduce leakage. For example, the battery cell stack 300 may also include a sealing material between the electrode assembly 120 and the membrane interlayer 100 (e.g., between the electrode assembly 120 and the frame member 102 and / or between the electrode assembly 120 and the frame member 110). The battery cell stack 300 may also include any space occupied by a sealing portion (such as a filling material) as disclosed herein (e.g., in a chamber above the membrane and / or in a chamber below the membrane) to prevent or minimize mechanical forces on the membrane.

[0089] The battery cell stack 300 also includes an electrically isolated end plate 124 in the adjacent layer of each outermost electrode assembly. The battery cell is disposed between a pair of electrically isolated end plates 124. Adjacent to the electrode assembly layer, electrical isolation is required to prevent short circuits. When the electrode assemblies contact each other, a short circuit may occur. Electrical isolation can be provided by a frame member. Therefore, one of the first or second frame members can be an electrode assembly. However, both the first and second frame members cannot be electrode assemblies. The electrically isolated end plate 124 can be a frame member. The electrically isolated end plate 124 can be a shell or part of a shell (i.e., a shell member) of the battery cell stack. Electrical isolation can be provided by the end plate 124 or a separate isolation plate (not shown). The end plate 124 can provide a way to fasten the layers of the battery cell stack together. The end plate 124 can include through holes for fasteners 128 (such as bolts, screws, clamps, etc.) to keep the layers of the battery cell stack together. Alternatively, the layers of the battery cell stack can be fastened together by sealing (e.g., by glue).

[0090] When the electrically isolating end plate 124 is a housing or housing member of a battery cell stack, the battery cells may be inserted into the housing 124 or a housing including the housing member 124. The housing or housing member 124 may provide a means for securing layers of the battery cell stack together.

[0091] Tests are performed on a system or cell stack according to an embodiment of the present disclosure. The cell stack includes a polymer ion exchange membrane having PEEK as part of or as a substitute for the polymer backbone. The cell stack includes a frame member made of polypropylene. The membrane is fixed between a polypropylene film and a polypropylene structural frame portion, and the fixed region includes a disclosed first region, a transition region, and a second region produced by ultrasonic welding. The fixed region also includes a disclosed third region. At the third region, the membrane is mechanically compressed between the polypropylene structural frame portion and a solid gasket adjacent to the polypropylene film. Pressure testing of the cell stack is performed by introducing air into a chamber above and below the membrane of the cell stack. The air is introduced at various pressures between 100 mbar and 800 mbar. After the air is introduced, a period of time is given to stabilize the pressure reading. After stabilization, the pressure in the chamber is measured to determine whether there is a leak. The pressure reading remains unchanged, indicating that no leak is observed within the pressure range tested.

Claims

1. A method of securing a membrane between a first frame member and a second frame member, the membrane having at least one property that renders it incompatible and incapable of securing it to the first and second frame members, the method comprising: generating a fixed region including a first region and a second region, wherein creating the first region comprises integrally bonding a first frame member to a second frame member, wherein no film is present in the first region, and Wherein creating the second region includes mechanically deforming the membrane between the first frame member and the second frame member.

2. The method according to claim 1, wherein: Each frame member is selected from the group consisting of a frame portion, a frame-compatible film, and an electrode assembly, as long as both frame members are not electrode assemblies.

3. The method according to claim 1 or 2, wherein: The first region is proximate first edges of the first and second frame members.

4. A method according to any preceding claim, wherein: The second region is adjacent to the first region, and the method further includes positioning the film in the second region between the first frame member and the second frame member.

5. A method according to any preceding claim, wherein: Producing the second region further includes producing a transition region where the integral bonding occurs, wherein the transition region is adjacent to the first region.

6. A method according to any preceding claim, wherein: The first region, the second region and optionally the transition region are produced by the sonotrode during the ultrasonic welding process, The ultrasonic welding electrode comprises a first zone and a second zone. the first region is complementary to the first area and the optional transition area, and the first region has a protrusion configured to pierce the membrane in the optional transition area, thereby allowing an integral bond to occur between the first frame member and the second frame member through the pierced membrane, and The second region is complementary to the second area, and the second area has a protrusion configured to mechanically deform the shape of the membrane in the second area.

7. A method according to any preceding claim, wherein: The fixing area comprises a third area, preferably proximate a second edge of the frame member opposite the first edge, and the method further comprises creating the third area by mechanically compressing the membrane, preferably using a protrusion of the frame member or using a sealing portion.

8. The method according to claim 7, wherein: When the membrane is mechanically compressed by the protrusions of the frame members, the membrane is mechanically compressed between the first frame member and the second frame member or between third frame members on the opposite side of the first or second frame member.

9. The method according to claim 7 or 8, wherein: The fixed area includes a fourth area, and the method further includes creating the fourth area between the second area and the third area by mechanically compressing the film using the sealing portion.

10. A method according to any preceding claim, wherein: The membrane is a diaphragm or an ion exchange membrane.

11. A unit stack comprising: At least one of the following: a membrane secured between the first frame member and the second frame member, the membrane having at least one property that imparts incompatibility to the membrane so that it cannot be secured to the first and second frame members, wherein the fixing region of the first frame member, the membrane, and the second frame member includes a first region and a second region, the first region includes the first frame member integrally bonded to the second frame member and no membrane is present in the first region, and the second region includes the membrane mechanically deformed between the first frame member and the second frame member; and a pair of electrode assemblies, wherein a diaphragm fixed between the first frame member and the second frame member is disposed between the pair of electrode assemblies; as well as electrically isolating end plates in adjacent layers of each outermost electrode assembly, Therein, the layers of the cell stack are fastened together.

12. The cell stack according to claim 11, wherein: The membrane is fixed between the first frame member and the second frame member according to the method of any one of claims 2-10.

13. The unit stack according to claim 11 or 12, wherein: The fixing area includes a third area including a protrusion or a sealing portion of the frame member and a diaphragm mechanically compressed by the protrusion or the sealing portion; and preferably, wherein the fixing area includes a fourth area including a diaphragm mechanically compressed by the sealing portion.

14. The unit stack according to any one of claims 11 to 13, wherein: The membrane is an ion exchange membrane and the cell stack is configured for use in a redox flow battery, an electrolyzer, or an electrodialysis cell.

15. Use of an ion exchange membrane in a unit stack according to any one of claims 11 to 14, wherein: The ion exchange membrane has at least one property that renders it incompatible with being secured to the first and second frame members of the cell stack.

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