Film stack unit

Abstract

To provide a film stack unit for a humidifier for a fuel cell powered vehicle.SOLUTION: A film stack unit (3) includes a rectangular parallelepiped film stack (4) and two sealing frames (10a, 10b). The present invention also relates to a humidifier (1) having a housing (2) and a film stack unit (3).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a membrane laminate unit for a humidifier for a vehicle powered by a fuel cell according to the preamble of claim 1. The invention also relates to a humidifier comprising a membrane laminate unit.

[0002] Humidifiers can be used, for example, in fuel cell systems to humidify the dry air flowing into the fuel cell with the moist air flowing out of the fuel cell. In this case, the humidifier generally comprises a housing and a membrane stack consisting of a number of flexible membranes. In this case, the membranes in the membrane stack are stacked and spaced apart from one another and glued together, so that the four sides of the membrane stack are gas-tightly connected to one another in pairs and gas-tightly separated from the other sides. This allows the dry air and the moist air to flow through the membrane stack in cross-flow and exchange moisture or water vapor with each other via the membranes. In order to prevent mixing of the dry air and the moist air in the humidifier, the respective sides through which the air can flow must be gas-tightly separated from one another. For this purpose, generally a rectangular parallelepiped, frame-shaped frame is used which is glued to the sides of the membrane stack. The membrane stack and the frame together form a so-called membrane stack unit, which is arranged in this case in the housing. In this case, the bonding of the frame to the membrane stack is carried out after the membrane stack has been mounted in the frame, which can be very laborious.

[0003] It is therefore an object of the present invention to provide an improved or at least alternative embodiment for a membrane stack unit of the type described in the generic phrase, which overcomes the above-mentioned disadvantages. It is also an object of the present invention to provide a corresponding humidifier with a membrane stack unit.

[0004] 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.

[0005] The invention is based on the general idea that the frame is made in parts, from at least two frame plates, which are provided with gluing grooves, so that assembly can be easily carried out.

[0006] The membrane stack unit according to the invention is provided or designed for a humidifier for a vehicle driven by a fuel cell. In this case, the membrane stack unit has a rectangular parallelepiped membrane stack with a number of flexible membranes stacked in a stacking direction. In this case, the membrane stack has four side faces through which air can flow, oriented parallel to the stacking direction, and two end faces through which air cannot flow, oriented transversely to the stacking direction. The membrane stack unit further has two sealing frames, which are arranged corresponding to two mutually opposite side faces of the membrane stack. Each sealing frame has an annular sealing area and an enclosing area protruding perpendicularly from the sealing area. In this case, the sealing area encloses the respective corresponding side face on the edge side and abuts against this side face. The enclosing area is turned towards the membrane stack and encloses the membrane stack on the edge side. According to the invention, each sealing frame has at least a recess in the surface of the sealing area facing the corresponding side face, which encloses the corresponding side face. Each recess is filled with an adhesive, and each sealing frame is tightly adhered to the film stack via the adhesive.

[0007] The membrane stack may be formed from a number of flexible membranes, the individual membranes being spaced apart from one another. The membranes may be formed in such a way that they are air-tight and moisture- or water vapor-permeable. Flow-permeable spacers or so-called spacers may be stacked between the membranes. The membranes and the spacers may be glued together in such a way that flow-permeable passages are formed between the membranes. Each passage may be air-tightly connected to two opposite sides of the membrane stack and may be gas-tightly separated from two other opposite sides of the membrane stack. The individual passages may be air-tightly connected to one another on the opposite sides, alternating in the stacking direction, so that the membrane stack as a whole is flow-permeable in cross-flow.

[0008] The four side faces through which air can pass and the two end faces through which air cannot pass define the membrane stack to the outside or form the outer surface of the rectangular membrane stack. The two end faces can be arranged on opposite sides and can be formed by the last membrane in the stacking direction. Alternatively, the membrane stack unit can have two sealing plates, which can be supported by the last membrane in the stacking direction and can be in particular sealed to the last membrane in the stacking direction. In this case, the sealing plates can be flush with the last membrane in the stacking direction and can form the end faces of the membrane stack. The sealing plates can be molded, for example, from plastic and can be, for example, glued to the last membrane in the stacking direction.

[0009] The membrane stack unit has two, in particular only two, sealing frames. Each sealing frame is formed from a sealing area and an enclosing area. In this case, the sealing area and the enclosing area can be molded integrally with one another or can merge into one another or can be inseparably connected to one another. In this case, the sealing area can be formed by a flat or flat frame. The sealing area located on the inside can have an edge, and the enclosing area can be designed to be located on the outside or on the side opposite the edge. The enclosing area is formed perpendicular to the sealing area. As a result, the sealing frame can have, in particular, an L-shaped cross section. In this case, the sealing area abuts against the respective corresponding side of the membrane stack. The enclosing area surrounds the membrane stack on the edge side and is arranged perpendicular to the respective side of the membrane stack or parallel to all faces adjacent to the respective side, i.e. the two end faces and the two adjacent side faces. The sealing frame can be molded, for example, from plastic.

[0010] A recess for adhesive is formed in the surface of the sealing area facing the corresponding side surface. In this case, the respective sealing frame is tightly glued to the film stack via the adhesive. In this case, the recess is formed in the sealing frame in an annular shape and can completely surround the corresponding side surface. In particular, the recess can follow the frame-like shape of the sealing area. The adhesive can be any adhesive that is liquid or flowable and hardens by additional treatment after application or without this treatment - i.e. with or without treatment. When attaching the sealing frame to the film stack, the adhesive can be introduced into the recess and the sealing frame can then be glued to the film stack. Due to the recess, a sufficient amount of adhesive can be applied, so that the adhesion of the sealing frame to the film block can be achieved in a reliable process.

[0011] In one possible embodiment of the membrane stack unit, each recess may be formed by a groove. The groove may be formed in particular with a space relative to the edge of the sealing area facing away from the enclosing area. The groove may completely surround the corresponding side and may be arranged with a space relative to the edge of the sealing area facing away from the enclosing area. The groove may furthermore be arranged with a space relative to the enclosing area. In other words, the groove may be separated by a respective web before the edge of the sealing area and / or from the enclosing area. The groove may be formed on each surface of the sealing area and may protrude into the sealing area. This allows the groove to accommodate a sufficient amount of adhesive and the sealing frame may be reliably bonded or glued to the membrane stack. The groove itself may have any cross section. In particular, the groove may have a U-shaped cross section.

[0012] In one possible alternative embodiment of the membrane stack unit, each recess may be formed by a groove that is open on one side. The groove may be bounded by at least one web and open to the surrounding area with respect to the edge of the sealing area facing away from the surrounding area. In other words, the groove may be spaced apart from the edge of the sealing area facing away from the surrounding area. In this case, the groove that is open on one side allows excess glue to flow out towards the surrounding area and also into the gap formed between the surrounding area and the membrane stack. This allows the glue to be freely distributed between the membrane stack and the sealing frame, which can simplify the metering of the glue. Furthermore, the flow out of excess glue towards the corresponding side surface can be avoided, which can avoid blocking of the air-guiding passages.

[0013] Each sealing frame may have at least one outflow groove for outflowing excess adhesive from the recess. In this case, the outflow groove may be fluidically connected to the recess and may lead from each recess to the edge of the sealing area opposite to the surrounding area and thus to the side of the membrane stack. Alternatively, the outflow groove may be fluidically connected to the recess and may lead from each recess to the surrounding area of ​​the sealing frame and thus to the gap located between the membrane stack and the surrounding area. Each outflow groove may be oriented, for example, perpendicular to each recess. Via each outflow groove, excess adhesive can be led out of the recess, which allows a reliable bonding between the sealing frame and the corresponding side. In order to lead out excess adhesive uniformly from the recess, multiple outflow grooves may be provided, which are formed uniformly or non-uniformly distributed around the annular recess. In this case, the multiple outflow grooves may be formed identically or differently from each other.

[0014] In one possible embodiment of the membrane stack unit, each sealing frame may have at least one overflow groove surrounding the corresponding side surface. In this case, the overflow groove may be formed in the surface of the sealing area facing the corresponding side surface, spaced apart from the recess and fluidically connected to the recess. The overflow groove can advantageously contain excess adhesive, which does not reach the corresponding side surface.

[0015] Each overflow groove may be located, for example, between the recess and the edge of the sealing area facing away from the surrounding area. Alternatively, each overflow groove may be located between the recess and the surrounding area of ​​the sealing frame. It is self-evident that each sealing frame may have two overflow grooves, which are different from each other or identical to each other. In this case, the overflow grooves may be formed in the form of grooves on both sides of each recess.

[0016] Each recess and each overflow groove may be fluidly connected to each other. For this purpose, a web formed between the recess and the overflow groove may be arranged at a distance from the corresponding side surface, so that a gap is formed between the web and the corresponding side surface. In this case, each recess and each overflow groove may be fluidly connected to each other via the gap. Alternatively or additionally, at least one connecting groove may be formed in the web formed between the recess and the overflow groove. In this case, the recess and each overflow groove may be fluidly connected to each other via the connecting groove.

[0017] In one possible embodiment of the membrane stack unit, it may be envisaged that each recess has at least two sections with mutually different heights and / or mutually different widths. In other words, each recess may vary in height and / or width along its longitudinal axis. Thereby, each sealing frame may be glued to the corresponding side or membrane stack in a number of different sections with different amounts of adhesive. Similarly, each overflow groove may have at least two sections with mutually different heights and / or mutually different widths. In other words, each overflow groove may vary in height and / or width along its longitudinal axis. Advantageously, the configuration of the overflow groove may be adapted to the configuration of the recess, or vice versa.

[0018] In the production of the membrane stack unit, in a first step, a membrane block can be produced. For this, the membrane and the flow-through spacers or spacers are glued together, and a sealing plate is placed on the last membrane in the stacking direction. The sealing plate can remain loosely placed on the last membrane in the stacking direction or alternatively can be glued on the last membrane in the stacking direction. This allows the production of a rectangular membrane block with four sides through which air can flow and two end faces through which air cannot flow. In a second step, the membrane stack can be glued to two sealing frames with a preload. For this, adhesive can be dispensed in advance into the recesses of the sealing frames, and then the sealing frames can be glued to the corresponding side faces. The recesses can then be overfilled, so that the sealing frames and the membrane stack can be joined to each other without any gaps. Via each outflow groove and / or each overflow groove and / or via a recess in the form of a groove open on one side, excess adhesive can be pushed inwardly towards the corresponding side or outwardly towards the surrounding area.

[0019] The invention also relates to a humidifier for a vehicle driven by a fuel cell, which humidifies dry air with moist air. The humidifier may in particular be provided for a fuel cell system with a fuel cell. In this case, the dry air may be air flowing into the fuel cell, and the moist air may be air flowing out of the fuel cell. In this case, the humidifier comprises a housing and a membrane stack unit as described above. In this case, the membrane stack unit is accommodated in the housing, and the sides of the membrane stack are at least partially sealed to one another in the housing by two sealing frames. The two sealing frames may be tightly sealed to the housing or another seal may be arranged between the housing and the two sealing frames. In this way, the respective sides of the membrane block through which air can pass may be hermetically separated from one another in the housing. If the membrane stack has a sealing plate, the sealing plate may also be tightly sealed to the housing. In order to avoid repetition, reference is made to the above description in this respect.

[0020] Further important features and advantages of the invention are evident from the subclaims, the drawings and the accompanying description of the drawings based on the drawings.

[0021] It is self-evident that the features mentioned above, and also below, can be used not only in the respective combinations mentioned, but also in other combinations or alone, without departing from the framework of the invention.

[0022] Preferred embodiments of the invention are illustrated and explained in more detail in the following description, where identical or similar or functionally identical components are designated by the same reference numerals and parts which are not directly visible are shown with dashed lines. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 is a schematic cross-sectional view of a humidifier according to the present invention, with air flow indicated; [Diagram 2] FIG. 2 shows a schematic exploded view of a membrane stack unit according to the invention for a humidifier according to the invention. [Diagram 3] FIG. 2 is a schematic diagram showing a membrane block of a membrane stack unit according to the present invention. [Figure 4] 1 is a schematic diagram showing a sealing frame of a film stack unit according to the present invention in a first embodiment. [Diagram 5] 4 is a schematic diagram showing a sealing frame of a film stack unit according to a second embodiment of the present invention. FIG. [Figure 6] FIG. 13 is a cross-sectional view showing a schematic view of a membrane stack unit according to the present invention, in a third embodiment, with a sealing frame. [Figure 7] FIG. 4 is a schematic cross-sectional view of a membrane stack unit according to the invention with a sealing frame in a fourth embodiment, without a membrane stack. [Figure 8] FIG. 11 is a cross-sectional view showing a schematic view of a membrane stack unit according to the present invention, provided with a sealing frame, in a fourth embodiment, together with a membrane stack.

[0024] 1 shows a cross-sectional view of a humidifier 1 according to the invention, in particular for fuel cell systems. In this case, the humidifier 1 has a two-part housing 2 and a membrane stack unit 3 according to the invention. The membrane stack unit 3 is accommodated in the housing 2.

[0025] In this case, the membrane stack unit 3 has a rectangular parallelepiped membrane stack 4 consisting of a number of flexible membranes 5. The membranes 5 are stacked at a distance from one another in the stacking direction ST, and for this purpose, spacers or spacers, not shown here, through which air can pass, may be arranged between the individual membranes 5. The membranes 5 are bonded to one another in such a way that a number of channels 6 and 7 through which air can pass are formed between the membranes 5. The membrane stack 4 thus has four side faces 6a, 6b, 7a, 7b arranged parallel to the stacking direction ST and through which air can pass, and two end faces 8a, 8b, not directly visible here but only by implication, oriented transversely to the stacking direction ST and through which air cannot pass.

[0026] The side surfaces 6a and 6b are arranged opposite one another and are connected to one another in an air-guiding manner by respective passages 6. In contrast, the side surfaces 6a and 6b are separated in an air-tight manner from the passages 7. The side surfaces 7a and 7b are likewise arranged opposite one another and are connected to one another in an air-guiding manner by respective passages 7. The side surfaces 7a and 7b are advantageously separated in an air-tight manner from the passages 6. The passages 6, 7 are arranged alternately in the stacking direction ST, so that the dry air TL and the humid air FL can flow in cross flow through the membrane stack 4 without mixing.

[0027] In this case, dry air TL flows through the passage 6, and humid air FL flows through the passage 7. The membrane 5 is air-impermeable and moisture- or water vapor-permeable, so that the dry air TL and the humid air FL can exchange moisture or water vapor with each other via the membrane 5. The end faces 8a and 8b of the membrane stack 4 are formed by two sealing plates 9a and 9b - not directly visible here, only by implication - which are firmly and sealingly connected to the last membrane 5 in the stacking direction ST, respectively. The sealing plates 9a and 9b may, for example, be glued to the last membrane 5 in the stacking direction ST, respectively.

[0028] The membrane stack unit 3 further includes two sealing frames 10a and 10b, which in this embodiment are arranged corresponding to the side surfaces 6a and 6b through which the dry air TL flows. However, it is self-evident that the sealing frames 10a and 10b may also be arranged corresponding to the side surfaces 7a and 7b through which the humid air FL flows. In this case, each sealing frame 10a and 10b has a sealing region 11 and an enclosing region 12, which are oriented perpendicular to each other. Thus, each sealing frame 10a or 10b has a substantially L-shaped cross section. Each sealing frame 10a and 10b is bonded to the membrane stack 4 at the corresponding side surfaces 6a and 6b, as will be described in more detail with reference to Figures 2 to 8.

[0029] The sealing area 11 of each sealing frame 10a or 10b is frame-shaped and surrounds the corresponding side surface 6a or 6b on the edge side. The sealing frame 10a or 10b is glued to the corresponding side surface 6a or 6b in the sealing area 11 via an adhesive 19. The surrounding area 12 is molded integrally with the sealing area 11 and protrudes towards the membrane block 4. In this case, the surrounding area 12 surrounds the membrane block 4 on the edge side.

[0030] The membrane stack unit 3 further includes two annular seals 13a and 13b, which are tightly sandwiched between the respective sealing frames 10a and 10b or between the sealing area 11 of each sealing frame 10a and 10b and the housing 2. The sealing frames 10a and 10b and the two seals 13a and 13b hermetically separate the two side surfaces 6a and 6b from each other in the housing 2 and from the remaining surfaces of the membrane stack 4. Furthermore, the two sealing plates 9a and 9b hermetically separate the two side surfaces 7a and 7b from each other in the housing 2. This allows the dry air TL and the humid air FL to flow without mixing in the housing 2 of the humidifier 1 and to exchange moisture or water vapor with each other through the membrane 5 in the membrane block 4.

[0031] The housing 2 is made of two parts, a first housing part 2a and a second housing part 2b. The two housing parts 2a and 2b are connected to each other in an airtight manner. In this case, the housing 2 is formed with a first inlet 14a and a first outlet 14b for dry air TL and a second inlet 15a and a second outlet 15b for moist air FL. In this case, the first inlet 14a is arranged corresponding to the side surface 6a, and the first outlet 14b is arranged corresponding to the side surface 6b. Similarly, the second inlet 15a is arranged corresponding to the side surface 7a, and the second outlet 15b is arranged corresponding to the side surface 7b. In this case, the sealing frames 10a and 10b, the seals 13a and 13b, and the sealing plates 9a and 9b hermetically separate the side surfaces 6a, 6b, 7a, 7b, the inlets 14a and 15a, and the outlets 14b and 15b from each other.

[0032] In FIG. 2, an exploded view of a membrane stack unit 3 according to the invention for a humidifier 1 according to the invention is shown. As mentioned above, the membrane stack unit 3 comprises a membrane stack 4 with a number of membranes 5. In FIG. 2, in particular, the end faces 8a and 8b through which air cannot pass are visible, which are provided with two sealing plates 9a and 9b. In this case, the sealing plates 9a and 9b each have a rib structure 16, which serves to support the membrane stack unit 3 and to prevent excessively strong swelling of the membranes, especially in the central area. For this purpose, sealing frames 10a and 10b engage the sealing plates 9a and 9b, respectively, in an encircling manner in the edge areas, thereby preventing the membrane stack 4 from expanding in the stacking direction ST or in the longitudinal direction. Furthermore, two sealing frames 10a and 10b are visible, which are glued to the side surfaces 6a and 6b of the membrane stack 4. Two seals 13a and 13b are arranged on the sealing frames 10a and 10b, which seal the membrane stack unit 3 against the housing 2.

[0033] In Fig. 3, a diagram of a membrane block 4 of a membrane stack unit 3 according to the invention is shown. As mentioned above, the membrane block 4 comprises a number of membranes 5 and sealing plates 9a and 9b. The individual membranes 5 are glued to one another, and the last membrane 5 in each case in the stacking direction ST is additionally glued to a sealing plate 9a and 9b. The membrane block 4 thus forms a continuous and inseparable structural unit.

[0034] In Fig. 4, a view of a sealing frame 10a or 10b of a membrane stack unit 3 according to the invention is shown in a first embodiment. In this case, the sealing frame 10a or 10b has a recess 17 on a surface 18 facing the corresponding side surface 6a or 6b. In this case, the recess 17 is formed in the form of a groove 17a and surrounds the correspondingly arranged respective side surface 6a or 6b of the membrane stack 4 on the edge side. In this case, the recess 17 is formed between an edge 20 of the sealing area 11 facing away from the surrounding area 12 and the surrounding area 12. In this case, the recess 17 is arranged at a distance from the edge 20 and the surrounding area 12. In other words, the recess 17 is separated from the edge 20 by a web 24. The recess 17 is filled with an adhesive 19, and each sealing frame 10a or 10b may be glued to the corresponding side surface 6a or 6b via the adhesive 19.

[0035] In FIG. 5, a view of a sealing frame 10a or 10b of a membrane stack unit 3 according to the invention is shown in a second embodiment. In contrast to the first embodiment of the sealing frame 10a or 10b, each sealing frame 10a or 10b now has a number of outflow grooves 21 which lead from the recess 17 - here the groove 17a - to the edge 20 or the corresponding side surface 6a or 6b. In this case, the outflow grooves 21 are formed in a web 24 formed between the recess 17 and the edge 20. Via the outflow grooves 21, excess adhesive 19 can flow out towards the corresponding side surface 6a or 6b, so that the recess 17 can be overfilled and the respective sealing frame 10a or 10b can be bonded to the corresponding side surface 6a or 6b without gaps. In other respects, the first and second embodiments of the respective sealing frame 10a or 10b correspond to each other.

[0036] FIG. 6 shows a cross-sectional view of a membrane stack unit 3 according to the invention with a sealing frame 10a or 10b according to a third embodiment. In the third embodiment, each sealing frame 10a or 10b has an overflow groove 22 in addition to the recess 17 - here the groove 17a - and the outflow grooves 21. In this case, the recess 17 and the outflow groove 21 are formed similarly to the second embodiment. The overflow groove 22 is formed between the recess 17 and the surrounding area 12 and spaced apart from the recess 17 and the surrounding area 12. The overflow groove 22 surrounds each correspondingly arranged side surface 6a or 6b or the recess 17 of the membrane stack 4. The recess 17 and the overflow groove 22 are preferably fluidly connected to each other. For this purpose, a web 23 formed between the overflow groove 22 and the recess 17 is formed spaced apart from the side surface 6a or 6b, so that a gap 25 is formed between the web 23 and the corresponding side surface 6a or 6b. For this purpose, the webs 23 have a correspondingly adapted height. Via the gaps 25, excess adhesive 19 can flow out of the recesses 17 into the overflow channels 22 and / or via the respective outflow channels 21 towards the corresponding side surfaces 6a or 6b.

[0037] FIG. 7 shows a cross-section of a membrane stack unit 3 according to the invention with a sealing frame 10a or 10b according to a fourth embodiment without a membrane stack 4. FIG. 8 shows a cross-section of a membrane stack unit 3 according to the invention with a sealing frame 10a or 10b according to a fourth embodiment with a membrane stack 4. In contrast to the other embodiments, in the fourth embodiment the recess 17 is formed in the form of a groove 17b which is open on one side. In this case, the groove 17b is closed towards the edge 20 of the sealing area 11 and open towards the surrounding area 12. This allows excess adhesive 19 to flow out of the recess 17 towards the surrounding area 12 and further into the gap 26 between the membrane stack 4 and the surrounding area 12. Furthermore, in the fourth embodiment, an overflow groove 22 is formed between the edge 20 and the recess 17. The fluid connection between the recess 17 and the overflow groove 22 is formed as in the third embodiment.

Claims

1. A membrane laminate unit (3) for a humidifier (1) for a vehicle powered by a fuel cell, comprising: The membrane stack unit (3) has a rectangular parallelepiped membrane stack (4) having a plurality of flexible membranes (5) stacked in a stacking direction (ST), The membrane stack (4) has four side surfaces (6a, 6b, 7a, 7b) through which air can pass and which are oriented parallel to the stacking direction (ST), and two end surfaces (8a, 8b) through which air cannot pass and which are oriented transversely to the stacking direction (ST), The membrane stack unit (3) has two sealing frames (10a, 10b), which are arranged corresponding to two opposite side surfaces (6a, 6b) of the membrane stack (4); Each of the sealing frames (10a, 10b) has an annular sealing region (11), and the sealing region (11) surrounds the corresponding side surface (6a, 6b) at an edge side and abuts against the side surface (6a, 6b); Each of the sealing frames (10a, 10b) has a surrounding area (12) that protrudes perpendicularly from the sealing area (11), the surrounding area (12) facing the membrane stack (4) and surrounding the membrane stack (4) on the edge side. In the membrane stack unit (3), Each of the sealing frames (10a, 10b) has at least a recess (17) on a surface (18) of the sealing region (11) facing the corresponding side surface (6a, 6b) and surrounding the corresponding side surface (6a, 6b); Each of the recesses (17) is filled with an adhesive (19), and each of the sealing frames (10a, 10b) is tightly bonded to the film laminate (4) via the adhesive (19). A membrane stack unit (3).

2. The membrane laminate unit (3) of claim 1, wherein each of the recesses (17) is formed by a groove (17a) that is spaced apart from an edge (20) of the sealing region (11) opposite the surrounding region (12).

3. The membrane laminate unit (3) according to claim 1, wherein each of the recesses (17) is formed by a groove (17b) that is open on one side, the groove (17b) being bounded by a web (24) at an edge (20) of the sealing area (11) opposite the enclosing area (12) and open towards the enclosing area (12).

4. Each of the sealing frames (10a, 10b) has at least one outflow groove (21) for allowing excess adhesive (19) to flow out of the recess (17), the outflow groove (21) being fluidly connected to the recess (17); Each of the outflow grooves (21) communicates with an edge (20) of the sealing region (11) opposite the surrounding region (12) from each of the recesses (17), and thus with the side surfaces (6a, 6b) of the membrane stack (4). A membrane stack unit (3) according to any one of claims 1 to 3.

5. Each of the sealing frames (10a, 10b) has at least one outflow groove (21) for allowing excess adhesive (19) to flow out of the recess (17), the outflow groove (21) being fluidly connected to the recess (17); the outflow groove (21) leads from each recess (17) to the surrounding area (12) of the sealing frame (10a, 10b) and thus to a gap (26) located between the membrane stack (4) and the surrounding area (12); A membrane stack unit (3) according to any one of claims 1 to 4.

6. Each of the sealing frames (10a, 10b) has at least one spill groove (22) surrounding the corresponding side surface (6a, 6b); the overflow groove (22) is formed in the surface (18) of the sealing region (11) facing the corresponding side surface (6a, 6b) at a distance from the recess (17) and is fluidly connected to the recess (17); A membrane stack unit (3) according to any one of claims 1 to 5.

7. Each of the overflow grooves (22) is located between the recess (17) and an edge (20) of the sealing area (11) of the sealing frame (10a, 10b) opposite the surrounding area (12), or Each of the overflow grooves (22) is located between the recess (17) and the surrounding area (12) of the sealing frame (10a, 10b). A membrane stack unit (3) according to claim 6.

8. a web (23) is formed between the recess (17) and the overflow groove (22), the web (23) being spaced apart from the corresponding side surface (6a, 6b) such that a gap (25) is formed between the web (23) and the corresponding side surface (6a, 6b), and each recess (17) and each overflow groove (22) are fluidly connected to each other via the gap (25); and / or A web (23) is formed between the recess (17) and the overflow groove (22), and at least one connecting groove is formed in the web (23), and the recess (17) and the overflow groove (22) are fluidly connected to each other via each connecting groove. A membrane stack unit (3) according to claim 6 or 7.

9. Each of said recesses (17) has at least two sections with different heights and / or different widths; and / or Each of the overflow channels (22) has at least two sections having different heights and / or different widths. A membrane stack unit (3) according to any one of claims 1 to 8.

10. A humidifier (1) for a vehicle driven by a fuel cell, which humidifies dry air (TL) with moist air (FL), comprising: The humidifier (1) comprises a housing (2) and a membrane stack unit (3) according to any one of claims 1 to 9, The membrane stack unit (3) is accommodated in the housing (2), and the side surfaces (6a, 6b) of the membrane stack (4) are at least partially sealed to each other by two sealing frames (10a, 10b) in the housing (2). Humidifier (1).

Images