Membrane stack, humidifier comprising membrane stack, and method for manufacturing membrane stack
By applying protective layers to spacers in the membrane stack, the issue of delamination and leakage in fuel cell humidifiers is resolved, ensuring a stable and durable bond, thus maintaining a hermetic seal.
Patent Information
- Application Number
- JP2025093175
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-06-05
- Filing Date
- 2025-06-04
- Publication Date
- 2025-12-17
AI Technical Summary
The challenge in existing membrane stacks for fuel cell humidifiers is the instability and delamination of membranes due to poor bonding between membrane materials and protective layers, leading to non-tightness and leakage.
Applying protective layers to spacers instead of membranes, ensuring a stable and durable bond between spacers and protective layers by direct material connection at their edges, using spacers with sufficient thickness and varying bonding methods.
Prevents delamination and ensures a secure, hermetic seal, preventing leakage and enhancing the durability of the membrane stack.
Smart Images
Figure 2025183945000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a membrane stack for a humidifier of a fuel cell system comprising at least one fuel cell according to the preamble of claim 1. The invention also relates to a humidifier for a fuel cell system comprising the membrane stack, and to a method for manufacturing the membrane stack.
[0002] In the membrane stack, flat membranes and spacers are alternately stacked in the stacking direction. The spacers form air-permeable passages between the membranes, which allow air to pass through them in directions perpendicular to the stacking direction and perpendicular to each other. Each passage is assigned to two different air flows. Because the membranes of the membrane stack are made of a vapor-permeable, airtight material, the two air flows can pass through the membrane stack without mixing and exchange moisture with each other. Such a membrane stack can be used, for example, in a humidifier for a fuel cell system with at least one fuel cell to humidify the dry supply air flowing to the fuel cell with the moist exhaust air flowing from the fuel cell.
[0003] The membranes are typically molded in multiple layers directly during production. In this case, the water vapor-permeable, airtight membrane material can be bonded to a protective material on both sides or one side. The protective material can protect the membrane material from tearing during the production of the membrane stack and from wear at the spacers during operation of the membrane stack. Unfortunately, a stable and lasting bond between the membrane material and the protective material is rarely achieved due to materials that are difficult to bond to each other and / or insufficient thickness. This can lead to delamination of the membrane material from the protective material during operation of the membrane stack, which can result in the membrane stack becoming non-tight.
[0004] The object of the present invention is therefore to provide an improved or at least an alternative embodiment of the membrane stack of the type described at the beginning, in which the above-mentioned disadvantages are eliminated, and also to provide a corresponding humidifier with the membrane stack and a corresponding method for producing the membrane stack.
[0005] This problem is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.
[0006] The invention is based on the general idea that any necessary supporting or protective layers are applied to the spacers or spacing bodies instead of to the membrane.
[0007] The membrane stack according to the present invention is provided or designed for use in a humidifier of a fuel cell system including at least one fuel cell. The membrane stack includes a plurality of flat membranes, which are stacked and spaced apart in a stacking direction. The membranes are water vapor permeable and airtight. The membrane stack further includes a plurality of first spacers and a plurality of second spacers, which are alternately arranged or stacked between the membranes in the stacking direction. The membrane stack allows a first flow direction through the first spacers perpendicular to the stacking direction, and a second flow direction through the second spacers. The first and second flow directions are oriented perpendicular to each other and perpendicular to the stacking direction. Each first spacer and each membrane adjacent to each first spacer are directly and materially connected to each other at their edges, i.e., at a limited section of their edges. Preferably, each first spacer and each membrane adjacent to each first spacer are welded or glued to each other. In the present invention, a protective layer is disposed between each first spacer and each membrane adjacent to each first spacer. Each protective layer and each first spacer adjacent to each protective layer are directly and materially connected to each other partially at their edges, i.e., at limited sections of their edges. Preferably, each protective layer and each first spacer adjacent to each protective layer are welded or glued to each other.
[0008] In the film stack according to the present invention, the first spacers and the protective layers can be freely adjusted to each other in terms of material. Furthermore, due to the sufficient thickness of the first spacers, the protective layers can be reliably bonded to the first spacers. This allows for a stable and durable material bond between the first spacers and the protective layers. The films are separated by the first spacers or bonded separately from the protective layers. This also allows for a stable and durable material bond between the first spacers and the film. Therefore, during operation of the film stack, delamination of the protective layers from the film and / or the first spacers, and thus non-hermeticity of the film stack, can be avoided.
[0009] Each protective layer may be molded from plastic (e.g., PET or PPS). Each protective layer may be molded from a woven material, a non-woven material, or a fleece. Each first spacer and / or each second spacer may be molded from plastic. Each first spacer and / or each second spacer may have, for example, an axial structure and / or a rib structure and / or a different flow-permeable structure. Each first spacer and each second spacer may be different from each other or may have a different structure from each other. This allows the passages in the film stack formed by each first spacer and each second spacer, or each first spacer and each second spacer, to be adapted to each air flow.
[0010] Each first spacer and each protective layer adjacent to each first spacer may be directly adjacent to each other at two first bonding regions on opposing edge sides, or may be materially bonded to each other. In this case, each first bonding region extends in the first flow direction. Each protective layer may be materially bonded to each first spacer only at both first bonding regions, or may be loosely attached to each first spacer between the first bonding regions. This allows for a secure and durable bond between the protective layer and the first spacer, while simplifying the bond formation. Each first spacer may be materially bonded to each protective layer adjacent to the first spacer in a point-like, linear, or surface manner. In the case of point-like bonding, the protective layer can be bonded to the first spacer simply at points, which allows for rapid bond formation. Furthermore, heat input to the first spacer and the protective layer can be reduced. In the case of a linear bond, the protective layer can be linearly bonded to the first spacer, which can form a consistent and therefore secure bond. In the case of a surface bond, a consistent and therefore particularly secure bond can be formed between the protective layer and the first spacer.
[0011] Each first spacer and each membrane adjacent to each first spacer may be in direct contact with each other or may be materially bonded to each other at two second bonding regions on opposing edge sides. In this case, each second bonding region extends in the first flow direction. Each membrane may be materially bonded to each first spacer only at both second bonding regions, and between both second bonding regions, each membrane may be loosely attached to a protective layer disposed between the membrane and the first spacer. Again, a secure and durable bond between each first spacer and each membrane can be easily achieved. In this case, a passage through which fluid can flow in the first flow direction may be formed between both second bonding regions. Each passage is airtightly bounded by both second bonding regions perpendicular to the first flow direction or in the second flow direction and by both membranes adjacent to each first spacer in the stacking direction. Preferably, each first spacer and each membrane may be airtightly bonded to each other at each second bonding region. Both protective layers are further disposed within each passage, but these protective layers do not affect the flow of the respective passages.
[0012] The film stack may be, in particular, rectangular. Each film and / or each protective layer and / or each first spacer and / or each second spacer may have a quadrilateral, preferably rectangular, cross section perpendicular to the stacking direction. In particular, each protective layer and each first spacer may have a quadrilateral, preferably rectangular, cross section perpendicular to the stacking direction. In this case, each first bonding region may be located on opposing sides of each protective layer and each first spacer. Furthermore, each film and each first spacer may have a quadrilateral, preferably rectangular, cross section perpendicular to the stacking direction. In this case, each second bonding region may be located on opposing sides of each film and each first spacer.
[0013] In each first spacer, the first and second bonding regions may be preferably located on the same side of the first spacer. In each first spacer, the first and second bonding regions may be spaced apart from each other perpendicular to the first flow direction, along the second flow direction, or in the second flow direction. In each first spacer, the first bonding region may be located inward relative to the second bonding region perpendicular to the first flow direction, along the second flow direction, or in the second flow direction, and the second bonding region may be located outward relative to the first bonding region perpendicular to the first flow direction, along the second flow direction, or in the second flow direction. This advantageously allows the first spacer to be reliably bonded independently to the protective layer and the membrane. In particular, this prevents adverse effects that may occur during the formation of one bond from affecting the other bond that has already been formed.
[0014] In each first spacer, each membrane may be located above each protective layer in the first bonding region, perpendicular to the first flow direction, along the stacking direction, or in the stacking direction. In each first spacer, each membrane may overhang above each protective layer in the second bonding region, perpendicular to the first flow direction, along the second flow direction, or in the second flow direction. In other words, each membrane may be longer than the protective layer in each first spacer, thereby directly contacting the first spacer in the second bonding region. Thus, each protective layer and each membrane may directly contact each first spacer in the first and second bonding regions, or may be directly materially bonded to each first spacer. In this case, each first spacer can be first bonded to its respective protective layer and then bonded to its respective membrane, and in this case, the already formed bond between each first spacer and protective layer does not adversely affect the subsequent bond between the first spacer and membrane.
[0015] The width of each membrane, defined perpendicular to the first flow direction or in the second flow direction, may be larger than the width of each protective layer, defined perpendicular to the first flow direction or in the second flow direction. Or, in other words, each membrane may have a larger area than each protective layer. In contrast, the width of each membrane, defined perpendicular to the first flow direction or in the second flow direction, may be equal to or approximately equal to the width of each first spacer, defined perpendicular to the first flow direction or in the second flow direction. Or, in other words, each membrane may have the same or approximately the same area as each first spacer. The width of each protective layer, defined perpendicular to the first flow direction or in the second flow direction, may be smaller than the width of each first spacer, defined perpendicular to the first flow direction or in the second flow direction. Or, in other words, each protective layer may have a smaller area than each first spacer. As a result, the protective layer and the membrane as a whole may be in direct contact with the first spacer or may be directly and materially bonded to the first spacer in each case.
[0016] In one possible embodiment, each protective layer may be disposed at the center of the first spacer, perpendicular to the first flow direction or in the second flow direction, so that both second bonding regions on the edge side are exposed for connecting the first spacer to the membrane. The protective layer may be directly and materially bonded to the spacer at each first bonding region, parallel to the first flow direction, on the edge side. The membrane may be disposed over the entire first spacer, completely covering the spacer and the protective layer. The membrane may be in direct contact with the first spacer at the second bonding region or may be directly and materially bonded to the first spacer. In each first bonding region, the first spacer is disposed between both protective layers and both membranes in the stacking direction. In this case, the protective layer is directly and materially bonded to the first spacer, and the membrane is positioned loosely above the protective layer. In each second bonding region, the first spacer is disposed between both membranes. In this case, each membrane is directly and materially bonded to the first spacer.
[0017] Each membrane may be formed, in particular, in a single layer. Each membrane may be formed from a layer of water vapor permeable and airtight material. Each membrane may be formed, in particular, in a single layer of water vapor permeable and airtight material. A single layer membrane may in particular prevent delamination of the membrane during operation of the membrane stack, thereby preventing leakage of the membrane stack. Each membrane may thus be formed separately from each protective layer.
[0018] Each second spacer may be materially bonded, preferably glued or welded, to each membrane adjacent to it. In this case, each second spacer and each membrane may be in direct contact with each other or materially bonded to each other at two edge-side third bonding regions extending opposite each other in the second flow direction. A passage through which fluid can pass in the second flow direction may be formed between both edge-side third bonding regions. In this case, each passage is airtightly defined by both third bonding regions perpendicular to the second flow direction and by both membranes adjacent to each second spacer in the stacking direction. For this purpose, the second spacer and each membrane may be airtightly bonded to each other at each third bonding region.
[0019] Each first spacer, each protective layer materially bonded to each first spacer, and each film materially bonded to each first spacer can form a prefabricated structural unit. In this case, the prefabricated structural unit may be prefabricated during the production of the film stack and can be further materially bonded to each second spacer during the production of the film stack. This can simplify the production of the film stack.
[0020] In one possible embodiment of the membrane stack, each first spacer may be designed to allow the humid exhaust gas flowing from the fuel cell to pass through, and each second spacer may be designed to allow the dry supply air flowing from the fuel cell to pass through. Since the dry supply air has a higher pressure than the humid exhaust gas, a higher pressure is generated in the passages formed by the second spacers than in the passages formed by the first spacers. Therefore, the membrane is constantly pressed against the first spacer. In this case, a protective layer is arranged between the first spacer and the membrane to protect the membrane from abrasion at the first spacer. In contrast, no protective layer is required between the second spacer and each membrane. This reduces the manufacturing cost of the membrane stack.
[0021] The present invention also relates to a method for producing the above-mentioned film stack. In this case, first, all first spacers are respectively partially and directly bonded, preferably glued or welded, to one protective layer on each side at their edges. The first spacers with protective layers, each second spacer, and each film are then stacked in the stacking direction, being partially and bonded, preferably welded or glued, to one another at their edges. In one possible embodiment, the first spacers with protective layers, the second spacers, and the film can be stacked one after the other in the stacking direction, and can be bonded to one another in a bonded manner. In an alternative embodiment, all first spacers with protective layers can be first bonded to one film on each side to form prefabricated structural units. Then, the structural units can be stacked alternately in the stacking direction with the respective second spacers, and can be bonded to one another in a bonded manner. To avoid repetition, please refer to the above description.
[0022] The present invention also relates to a humidifier for a fuel cell system including at least one fuel cell. The humidifier is particularly provided or designed to humidify dry supply air flowing to the fuel cell with humid exhaust air flowing from the fuel cell. In this case, the humidifier includes the above-described membrane stack and a housing. In this case, the membrane stack is contained within the housing and sealed to the housing so that the dry supply air and the humid exhaust air can flow through the housing and the membrane stack without mixing. Furthermore, the membrane stack is oriented within the housing so that the humid exhaust air can flow through the membrane stack in a first flow direction through the first spacer, and the dry supply air can flow through the membrane stack in a second flow direction through the second spacer. That is, during operation, the humid exhaust air passing through the membrane stack flows through the first spacer in the first flow direction, and the dry supply air passing through the membrane stack flows through the second spacer in the second flow direction. Since the dry intake air has a higher pressure than the humid exhaust air, a higher pressure is generated in the passage formed by the second spacer than in the passage formed by the first spacer. This causes the membrane to be pressed against the first spacer, but not against the second spacer, during operation of the humidifier. In this case, the protective layer between the first spacer and the membrane can protect the membrane. In contrast, no protective layer is required between the second spacer and the membrane. This reduces the manufacturing cost of the membrane stack. To avoid repetition, please refer to the above description.
[0023] Important further features and advantages of the invention are apparent from the dependent claims, the drawings and the corresponding illustrations based on the drawings.
[0024] Naturally, the features mentioned above and those further described below can be used not only in the combinations described respectively, but also in other combinations or alone, without departing from the scope of the invention.
[0025] Preferred embodiments of the present invention are illustrated in the drawings and explained in detail in the following description, where identical reference numerals refer to identical or similar or functionally identical components, and where multiple components are illustratively numbered for clarity. [Brief explanation of the drawings]
[0026] [Figure 1] 1 is an exploded view showing a schematic view of a humidifier according to the invention, comprising a membrane stack according to the invention; [Figure 2] 1 is a schematic cross-sectional view of a film stack according to the present invention shown with air flow. [Figure 3] 1 is a schematic side view of a first spacer provided with a protective layer of a film stack according to the present invention; FIG. [Figure 4] 1 is a schematic side view of a first spacer of a film stack according to the present invention, the spacer comprising a protective layer and a film; [Figure 5] 1 is a schematic plan view of a first spacer with a protective layer of a film stack according to the present invention having linear bonds; FIG. [Figure 6] 1 shows a schematic plan view of a first spacer with a protective layer of a film stack according to the invention with point-like bonds; FIG.
[0027] FIG. 1 shows an exploded view of a humidifier 1 according to the present invention. The humidifier 1 is designed for a fuel cell system with at least one fuel cell, in order to humidify dry supply air ZL flowing to the fuel cell with moist exhaust air AL flowing from the fuel cell. The humidifier 1 comprises a membrane stack 2 according to the present invention and a housing 3. The membrane stack 2 comprises multiple flat membranes 4 stacked one above the other in a stacking direction ST. The membranes 4 are water vapor permeable and airtight. First spacers 5 and second spacers 6 are alternately stacked between the membranes 4. Furthermore, a protective layer 7 is disposed between each first spacer 5 and each membrane 4 adjacent to the first spacer 5. The membranes 4, the spacers 5 and 6, and the protective layer 7 are bonded to one another. The structure of the membrane stack 2 will be described in more detail below with reference to FIGS. 2 to 6.
[0028] The membrane stack 2 is shaped like a rectangular parallelepiped and has two opposing outer surfaces 8a and 8b, two opposing outer surfaces 9a and 9b, and two opposing end surfaces 10a and 10b. In this case, both outer surfaces 8a and 8b of the membrane stack 2 are connected to each other so that wet exhaust air AL can flow through a first spacer 5 in a first flow direction SR1. In this case, both outer surfaces 9a and 9b of the membrane stack 2 are connected to each other so that dry intake air ZL can flow through a second spacer 6 in a second flow direction SR2. Both end surfaces 10a and 10b of the membrane stack 2 are formed by two seal plates 11a and 11b airtightly connected to the last membrane 4 of each membrane stack 2, and are therefore impermeable. Due to the stacking of the membranes 4 in the membrane stack 2, the outer faces 8a, 8b, 9a, 9b are oriented parallel to the stacking direction ST, and the end faces 10a and 10b are oriented perpendicular to the stacking direction ST.
[0029] The membrane stack 2 is accommodated in a housing 3, and is sealed using two seal members 12a and 12b surrounding the outer surfaces 8a and 8b and seal plates 11a and 11b so that the outer surfaces 8a, 8b, 9a, 9b are airtightly separated from one another within the housing 3. In this embodiment, the housing 3 has a pot-shaped housing body 3a and a cover 3b that closes the housing body 3a. Furthermore, the housing 3 is formed with an inlet 13a connected to the outer surface 8a in an air-guiding manner and an outlet 13b connected to the outer surface 8b in an air-guiding manner, and the inlet 13a and outlet 13b are designed to supply and discharge humid exhaust air AL to and from the membrane stack 2. Furthermore, the housing 3 is formed with an inlet 14a connected to the outer surface 9a in an air-guided manner and an outlet 14b connected to the outer surface 9b in an air-guided manner, the inlet 14a and the outlet 14b being designed for supplying dry supply air ZL to the membrane stack 2 and for withdrawing it from the membrane stack 2.
[0030] During operation of the humidifier 1, the moist exhaust air AL enters the humidifier 1 through the inlet 13a and flows toward the outer surface 8a of the membrane stack 2. The moist exhaust air AL then flows from the outer surface 8a to the outer surface 8b through the first spacer 5 or through a passage formed in the membrane stack 2 by the first spacer 5. The moist exhaust air AL then exits the humidifier 1 through the outlet 13b. The dry supply air ZL enters the humidifier 1 through the inlet 14a and flows toward the outer surface 9a of the membrane stack 2. The dry supply air ZL then flows from the outer surface 9a to the outer surface 9b through the second spacer 6 or through a passage formed in the membrane stack 2 by the second spacer 6. The dry supply air ZL then exits the humidifier 1 from the outer surface 9b through the outlet 14b. Because the membrane 4 is airtight, the dry supply air ZL and the moist exhaust air AL flow through the membrane stack 2 without mixing. Since the membrane 4 is water vapor permeable, the dry intake air ZL can be humidified by the moist exhaust air AL.
[0031] 2 shows a cross-sectional view of a portion of a film stack 2 according to the present invention. The film stack 2 includes a plurality of films 4, a plurality of first spacers 5, a plurality of second spacers 6, and a plurality of protective layers 7, which are materially bonded to one another. In this example, the first spacers 5 and the second spacers 6 are alternately arranged in the stacking direction ST, and the film 4 is stacked between the spacers 5 and 6. In this example, the protective layers 7 are each arranged between the first spacers 5 and adjacent films 4. In this example, the film 4 is bonded to the spacers 5 and 6, and the protective layers 7 are welded to the first spacers 5.
[0032] The first spacer 5 is designed to fluidly connect the opposing outer surfaces 8a and 8b of the membrane stack 2 to allow the humid exhaust air AL to flow through. The second spacer 6 is designed to fluidly connect the opposing outer surfaces 9a and 9b of the membrane stack 2 to allow the dry supply air ZL to flow through. During operation of the humidifier 1 or the membrane stack 2, the dry supply air ZL has a higher pressure than the humid exhaust air AL. This causes the membrane 4 to be pressed against the first spacer 5, as shown in an exaggerated manner in FIG. 2. A protective layer 7 between the membrane 4 and the first spacer 5 protects the membrane 4 from abrasion. No protective layer is needed or provided between the second spacer 6 and the membrane 4.
[0033] 3 shows a side view of a first spacer 5 equipped with a protective layer 7. In this case, the protective layer 7 is arranged on both sides of the first spacer 5 and is directly and material-bonded to the first spacer 5 at the edge in two opposing first bonding regions 15, i.e., without an additional intermediate layer. In this example, the protective layer 7 is welded to the first spacer 5. In this case, the protective layer 7 has a smaller width than the first spacer 5, which exposes the first spacer 5 to the sides and outside of the first bonding regions 15.
[0034] FIG. 4 shows a side view of a first spacer 5 with a protective layer 7 and a membrane 4. In this case, the membrane 4 is arranged on both sides of the first spacer 5 and is directly and materially bonded to the first spacer 5 at the edge in two opposing second bonding regions 16, i.e., without an additional intermediate layer. In this embodiment, the membrane 4 is glued to the first spacer 5. For this purpose, the membrane 4 has a greater width than the protective layer 7 and protrudes beyond it laterally. As a result, the first bonding regions 15 and the second bonding regions 16 are spaced apart, and both the membrane 4 and the protective layer 7 are directly bonded to the first spacer 5. This prevents delamination and leakage of the membrane stack 2.
[0035] 5 shows a plan view of a first spacer 5 with a protective layer 7. Here, the first spacer 5 has a wave-like structure and is linearly bonded or welded to the protective layer 7. FIG. 6 shows a plan view of a first spacer 5 with a protective layer 7. Here, the first spacer 5 has a cross-like structure and is point-bonded or welded to the protective layer 7.
Claims
1. A membrane stack (2) for a humidifier (1) of a fuel cell system comprising at least one fuel cell, comprising: The membrane stack (2) has a plurality of water vapor permeable and airtight flat membranes (4), which are stacked in a stacking direction (ST) at intervals from each other; The film stack (2) has a plurality of first spacers (5) and a plurality of second spacers (6), and the first spacers (5) and the second spacers (6) are alternately arranged between the films (4) in the stacking direction (ST); The membrane stack (2) is capable of flowing through the first spacer (5) in a first flow direction (SR1) perpendicular to the stacking direction (ST) and through the second spacer (6) in a second flow direction (SR2) oriented perpendicular to the first flow direction (SR1), Each of the first spacers (5) and each of the membranes (4) adjacent to each of the first spacers (5) are partially and directly materially connected to each other on the edge side, preferably by welding or adhesive. In the film stack (2), a protective layer (7) is disposed between each of the first spacers (5) and each of the membranes (4) adjacent to each of the first spacers (5); Each of the protective layers (7) and each of the first spacers (5) adjacent to each of the protective layers (7) are partially and directly materially connected to each other on the edge side, preferably by welding or bonding. A membrane stack (2).
2. Each of the first spacers (5) and each of the protective layers (7) adjacent to each of the first spacers (5) are in direct contact with each other and are materially bonded to each other in two first bonding regions (15) on the edge sides extending opposite each other in the first flow direction (SR1); and / or Each of the first spacers (5) and each of the membranes (4) adjacent to each of the first spacers (5) are in direct contact with each other and are materially bonded to each other at two second bonding regions (16) on the edge sides extending opposite each other in the first flow direction (SR1).
2. The membrane stack (2) according to claim 1, characterized in that it comprises:
3. 3. The membrane stack (2) according to claim 2, characterized in that in each of the first spacers (5), the first bonding region (15) and the second bonding region (16) are arranged spaced apart from each other perpendicular to the first flow direction (SR1).
4. 4. The membrane stack (2) according to claim 2 or 3, characterized in that in each of the first spacers (5), the first bonding region (15) is arranged so as to be positioned relatively inward with respect to the second bonding region (16) perpendicular to the first flow direction (SR1), and the second bonding region (16) is arranged so as to be positioned relatively outward with respect to the first bonding region (15) perpendicular to the first flow direction (SR1).
5. Each of the membranes (4) is located above each of the protective layers (7) adjacent to each of the first spacers (5) perpendicular to the first flow direction (SR1) in each of the first bonding regions (15), and / or Each of the membranes (4) overhangs, in each of the second bonding regions (16), perpendicular to the first flow direction (SR1), above each of the protective layers (7) adjacent to each of the first spacers (5).
5. The membrane stack (2) according to any one of claims 2 to 4, characterized in that it is
6. each of the protective layers (7) and each of the first spacers (5) has a quadrangular, preferably rectangular, cross section perpendicular to the stacking direction (ST), and the first bonding areas (15) are arranged on opposite sides of each of the protective layers (7) and each of the first spacers (5), respectively; and / or Each of the membranes (4) and each of the first spacers (5) has a quadrangular, preferably rectangular, cross section perpendicular to the stacking direction (ST), and the second bonding regions (16) are arranged on opposite sides of each of the membranes (4) and each of the first spacers (5), respectively.
6. The membrane stack (2) according to any one of claims 1 to 5, characterized in that it is
7. the width of each of the membranes (4), defined perpendicular to the first flow direction (SR1), is greater than the width of each of the protective layers (7), defined perpendicular to the first flow direction (SR1); and / or the width of each of the membranes (4), defined perpendicular to the first flow direction (SR1), is equal to the width of each of the first spacers (5), defined perpendicular to the first flow direction (SR1); and / or The width of each of the protective layers (7) defined perpendicular to the first flow direction (SR1) is smaller than the width of each of the first spacers (5) defined perpendicular to the first flow direction (SR1).
7. The membrane stack (2) according to any one of claims 1 to 6, characterized in that it is
8. 8. The film stack (2) according to claim 1, wherein each of the first spacers (5) is materially connected to each of the protective layers (7) adjacent to each of the first spacers (5) in a point-like, linear, or surface-connected manner.
9. Each of said membranes (4) is formed in a single layer, and / or Each of said membranes (4) is formed from a layer of water vapor permeable and airtight material; and / or Each of said membranes (4) is formed from only one layer of a single layer of water vapor permeable and airtight material.
9. The membrane stack (2) according to any one of claims 1 to 8, characterized in that it is
10. Each of the first spacers (5) is designed to allow the passage of humid exhaust gas (AL) flowing from the fuel cell; Each of the second spacers (6) is designed to allow the dry intake air (ZL) to flow through the fuel cell.
10. The membrane stack (2) according to any one of claims 1 to 9, characterized in that it is
11. A method for producing a membrane stack (2) according to any one of claims 1 to 10, comprising: all first spacers (5) are partly and directly connected to one another in a material-tight manner on their edge sides to one protective layer (7) on each side, preferably by gluing or welding, The first spacer (5) provided with the protective layer (7), each second spacer (6) and each membrane (4) are stacked in a stacking direction (ST) and are partially and materially bonded to each other at the edge side, preferably by welding or gluing. method.
12. A humidifier (1) for a fuel cell system with at least one fuel cell for humidifying dry intake air (ZL) flowing to the fuel cell with moist exhaust air (AL) flowing from the fuel cell, the humidifier comprising: The humidifier (1) comprises a membrane stack (2) according to any one of claims 1 to 10 and a housing (3), The membrane stack (2) is housed in the housing (3) and sealed to the housing (3) so that the humid exhaust air (AL) and the dry intake air (ZL) can flow through the housing (3) and the membrane stack (2) without mixing; The membrane stack (2) is oriented within the housing (3) so that the humid exhaust air (AL) can flow through the membrane stack (2) in a first flow direction (SR1) through a first spacer (5) and the dry supply air (ZL) can flow through the membrane stack (2) in a second flow direction (SR2) through a second spacer (6). Humidifier (1).