HUMIDIFIER

Description

[0001] The invention relates to a humidifier for humidifying dry cathode supply air by means of moist cathode exhaust air in a fuel cell system according to the preamble of claim 1.

[0002] A humidifier in a fuel cell system is used to humidify dry cathode supply air using moist cathode exhaust air. The fuel cell system can be used, in particular, to power vehicles. A typical humidifier comprises a housing and a membrane stack, which is contained within the housing and consists of several membranes stacked at intervals. Channels are formed between adjacent membranes of the membrane stack, through which the cathode supply air and the cathode exhaust air flow alternately. The membranes are airtight but permeable to water vapor, so that the cathode supply air and the cathode exhaust air are separated by the membranes, yet the cathode supply air can still be humidified by the cathode exhaust air passing through the membranes.From DE 10 2014 006 394 A1, for example, it is known to separate the cathode supply air and the cathode exhaust air in the humidifier housing airtight by means of several seals. Disadvantageously, this results in a very complex humidifier design. DE 10 2019 123534 discloses a humidifier for fuel cells with a cuboid flat membrane stack and sealing rings on the short sides. The sealing rings can be made of an elastomer or an adhesive. DE 10 2014 006394 discloses a humidifier for fuel cells with flat membranes and seals on the edges of the long sides. US 2015 / 162627 discloses a humidifier for fuel cells with end plates. The membranes are surrounded by frame parts and stacked on top of each other, creating a membrane stack that can be inserted into the housing, with the insertion occurring parallel to the flow-through sides. The housing has struts in the corners that provide support for the diaphragm stack.These could be considered a support frame. However, this frame cannot be inserted into the housing; rather, the struts are already part of the housing. After inserting the stack, the longitudinal edges are sealed using a hardening sealant. The sealant must be injected from the outside through a total of four holes in the struts ("lateral supports") and then cured.

[0003] The object of the invention is therefore to provide an improved or at least alternative embodiment for a humidifier of the generic type, in which the described disadvantages are overcome.

[0004] This problem is solved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0005] A humidifier is designed to humidify dry cathode supply air in a fuel cell system using moist cathode exhaust air. The humidifier comprises a housing with an interior chamber and a membrane stack arranged within this chamber. The membrane stack has six sides and can be inserted longitudinally into the housing chamber. Two of the opposing sides of the membrane stack are hermetically sealed. Two other opposing sides of the membrane stack are open to the dry cathode supply air in a supply air flow path, and two other opposing sides of the membrane stack are open to the moist cathode exhaust air in an exhaust air flow path, allowing non-mixing airflow.Between each flowable side surface of the membrane stack and the housing, an air chamber is formed for supplying or removing cathode supply air in the supply air flow path or for supplying or removing cathode exhaust air in the exhaust air flow path to / from the membrane stack. According to the invention, two of the flowable side surfaces of the membrane stack are oriented transversely to the longitudinal direction and allow flow in the longitudinal direction, and two other flowable side surfaces of the membrane stack are oriented parallel to the longitudinal direction and allow flow transversely to the longitudinal direction. The non-flowable side surfaces of the membrane stack are then oriented parallel to the longitudinal direction.

[0006] The membrane stack comprises several membranes, the membranes of which are stacked at intervals transversely to the longitudinal direction within the housing, according to the inventive arrangement of the flowable side surfaces of the membrane stack. Advantageously, the membranes can be designed as flat membranes. Advantageously, the membranes can be very thin, preferably film-like. Supply air channels and exhaust air channels are formed between the individual membranes. The supply air channels are associated with the supply air flow path and connect a first pair of the flowable and opposing side surfaces of the membrane stack to each other in an air-conducting manner. The exhaust air channels are associated with the exhaust air flow path and connect a second pair of the flowable and opposing side surfaces of the membrane stack to each other in an air-conducting manner.The supply air ducts are expediently separated from the second pair of side surfaces, and the exhaust air ducts from the first pair of side surfaces. The two non-flow-through side surfaces of the membrane stack are expediently sealed airtight. The membranes of the membrane stack are airtight and permeable to water vapor, allowing the cathode supply air and cathode exhaust air to flow through the membrane stack without mixing, and the cathode supply air to be humidified by the cathode exhaust air as it passes through the membranes. The term "permeable to water vapor" here and subsequently means that the membranes of the membrane stack are permeable to water vapor, allowing water vapor from the cathode exhaust air to pass through the membranes to the cathode supply air.

[0007] The longitudinal direction of the humidifier according to the invention is defined by the direction in which the membrane stack is inserted into the housing. The membrane stack is preferably cuboid in shape, and one longitudinal axis of the membrane stack can be oriented longitudinally. Advantageously, the longest edges of the membrane stack can be oriented longitudinally. The flow-through surfaces oriented transversely to the longitudinal direction and the flow-through surfaces oriented parallel to the longitudinal direction can have different geometric shapes. The supply air flow path and the exhaust air flow path within the membrane stack can have different lengths.

[0008] The housing can be open at one end, or pot-shaped or bucket-shaped, with a base and a lid. The housing body, or its longitudinal axis, is then oriented longitudinally, while the base and lid are oriented transversely to this longitudinal direction. The flow-through surfaces, oriented transversely to the longitudinal direction, are then positioned facing the base and the lid, respectively. Alternatively, the housing can be open at both ends, or tubular, with two lids. In this case, the housing body, or its longitudinal axis, is oriented longitudinally, while the respective lids are oriented transversely to this longitudinal direction. The flow-through surfaces, oriented transversely to the longitudinal direction, are then positioned facing the respective lids.The cross-section of the tubular or pot-shaped housing body perpendicular to the longitudinal direction can be round, oval, polygonal, rhombic, rectangular, or square.

[0009] In the humidifier according to the invention, the sealing of the air chambers, which are associated with the flow-through side surfaces of the membrane stack oriented transversely to the longitudinal direction, can advantageously be carried out transversely to the longitudinal direction, thus simplifying the process. In particular, conventional longitudinally oriented sealing windows in the housing can be omitted. This reduces the number of undercuts in the housing and consequently also the number of slides required for its manufacture. Therefore, the arrangement of the flow-through side surfaces of the membrane stack in the housing according to the invention simplifies the overall design of the humidifier and reduces manufacturing costs.

[0010] Advantageously, the membrane stack can be designed to be cuboidal. A longitudinal axis and the longest edges of the membrane stack are then aligned parallel to the longitudinal direction. Due to the arrangement of the flow-through surfaces of the membrane stack according to the invention, the membranes of the membrane stack are stacked transversely to the longitudinal direction within the housing. If the longest edges of the membrane block are aligned along the longitudinal direction, the membranes are stacked along the short edge of the membrane stack that is oriented transversely to the longitudinal direction. Compared to a conventional membrane stack, in which the membranes are stacked longitudinally and thus along the longest edge of the membrane stack, the number of membranes or layers to be stacked can be reduced.This simplifies the construction of the membrane stack and also advantageously reduces the cycle time for its production linearly. Consequently, the manufacturing costs of the membrane stack and the humidifier as a whole can be reduced.

[0011] Advantageously, the side surfaces that are perpendicular to the longitudinal direction and open to airflow can be assigned to the supply air flow path. The supply air flow path is then oriented longitudinally and can be permeated by cathode supply air in the longitudinal direction. Similarly, the side surfaces that are perpendicular to the longitudinal direction and open to airflow parallel to the longitudinal direction can be assigned to the exhaust air flow path. The exhaust air flow path is then oriented perpendicular to the longitudinal direction and can be permeated by cathode exhaust air in the transverse direction. Due to water condensation, the moist cathode exhaust air in the exhaust air flow path tends to have a higher pressure drop than the dry cathode supply air in the supply air flow path. If the membrane stack is cuboid and its longest edges are oriented longitudinally, a particularly advantageous airflow through the membrane stack can be achieved.

[0012] In the membrane stack oriented in this way, the flowable side surfaces parallel to the longitudinal direction have a larger geometric area than the flowable side surfaces oriented perpendicular to the longitudinal direction. Furthermore, the flow path within the membrane stack between the flowable side surfaces parallel to the longitudinal direction is smaller than the flow path within the membrane stack between the flowable side surfaces oriented perpendicular to the longitudinal direction. The flowable side surfaces parallel to the longitudinal direction, with their larger geometric area and smaller flow path within the membrane stack, are therefore assigned to the exhaust air flow path. This reduces the pressure drop in the wet cathode exhaust air, which tends to experience pressure loss.The permeable side surfaces, oriented transversely to the longitudinal direction, with a smaller geometric area and a larger flow path within the membrane stack, are assigned to the supply air flow path. Since the dry cathode supply air does not tend to cause any pressure loss, the smaller geometric area and the larger flow path within the membrane stack are not critical.

[0013] In an advantageous embodiment of the humidifier, the humidifier is provided with a support frame. The membrane stack is inserted into the support frame, and the support frame is inserted into the housing. The airflow-permeable side surfaces of the membrane stack are connected to the associated air chambers via the support frame. The support frame securely holds the membrane stack and fixes it firmly within the housing. This significantly simplifies the assembly of the humidifier. Furthermore, sealing the membrane stack to the housing is simplified by the support frame. Advantageously, the support frame can also compensate for tolerances of the membrane stack and the housing. The support frame is a separate element and can advantageously be made of plastic. The support frame can advantageously be dimensionally stable and self-supporting.The support frame can be one-piece or multi-piece.

[0014] Advantageously, the humidifier can have two opposing sealing plates, with the sealing plates bearing against the non-flowable side surfaces of the membrane stack. The shape and size of each sealing plate can correspond to the respective non-flowable side surface. The non-flowable side surfaces of the membrane stack are aligned parallel to the longitudinal direction within the housing. Each sealing plate can also be bonded to its corresponding side surface of the membrane stack in a material-bonded and airtight manner – for example, by adhesive bonding. Advantageously, the respective sealing plates can be formed on the support frame described above.

[0015] Additionally, the sealing plate can be designed to seal tightly against the housing. This sealing plate can be shaped so that, during operation of the humidifier, it is deformable by the internal operating pressure within the membrane stack and pressed firmly against the housing. Alternatively or additionally, the sealing plate can be designed to be deformable so that, when the internal operating pressure is present within the membrane stack, it is pressed firmly against the housing. This ensures that the air chambers associated with the two air-flowable side surfaces, which are oriented parallel to the longitudinal direction, are hermetically sealed from each other perpendicular to the direction of circulation. The direction of circulation is thus perpendicular to the longitudinal direction.

[0016] Within the housing, the air chambers associated with the flow-through side surfaces and the sealing plates associated with the non-flow-through side surfaces alternate in the direction of rotation. The sealing plates are airtightly connected to the membrane stack and to the housing, so that the two air chambers associated with the two flow-through side surfaces oriented parallel to the longitudinal direction are airtightly separated from each other by the sealing plates.

[0017] Alternatively, at least one longitudinally oriented sealing rib can be formed on each sealing plate, and this sealing rib abuts the housing in a sealing manner. The air chambers associated with the two flow-through side surfaces oriented parallel to the longitudinal direction are thus airtightly separated from each other transversely to the direction of rotation. The direction of rotation is circular, around the longitudinal direction. As explained above, the air chambers associated with the flow-through side surfaces and the sealing plates associated with the non-flow-through side surfaces alternate in the housing in the direction of rotation. The sealing plates are airtightly connected to the membrane stack, and the sealing rib abuts the housing in a sealing manner, so that the two air chambers associated with the two flow-through side surfaces oriented parallel to the longitudinal direction are airtightly separated from each other by the sealing rib.

[0018] Advantageously, the respective sealing plate or sealing rib on the sealing plate can be designed such that, during operation of the humidifier, the respective sealing plate or sealing rib can be pressed firmly against the housing to create a seal. The membrane stack comprises several membranes, which are flexible and can deform under pressure. During operation, the internal operating pressure of the membrane stack is higher than the external pressure, and the membrane stack expands outwards. However, it is understood that the deformation of the membrane stack described here is minimal and does not affect the function or structure of the membrane stack or the humidifier.The described deformation presses the respective sealing plate or sealing rib on the sealing plate against the housing, and the two air chambers, which correspond to the two flow-through side surfaces oriented parallel to the longitudinal direction, are reliably and airtightly separated from each other. Additionally, an elastic seal can be arranged between the sealing plate or the sealing rib on the sealing plate and the housing – for example, clamped and / or pressed in place. The seal can, for example, be made of a hardened adhesive compound.

[0019] Advantageously, the humidifier can be provided with two elastic ring seals. Each ring seal encircles the perpendicular side surface of the membrane stack and is arranged to seal between the housing and the support frame or between the housing and the perpendicular side surface – for example, by clamping and / or pressing it in place. This seal isolates the air chamber associated with that side surface from the adjacent air chambers. Advantageously, each ring seal can be made of a hardened adhesive compound.

[0020] Advantageously, sealing the membrane stack to the housing can be achieved particularly simply using only the two ring seals and the two sealing plates – with or without the sealing ribs. The sealing plates, or the sealing ribs on the sealing plates, create an airtight separation between the two air chambers corresponding to the two flow-through side surfaces oriented parallel to the longitudinal direction. The two ring seals then create an airtight separation between the two air chambers corresponding to the two flow-through side surfaces oriented perpendicular to the longitudinal direction and the air chambers corresponding to the two flow-through side surfaces oriented parallel to the longitudinal direction. This ensures a reliable seal between the membrane stack and the housing, significantly reducing the complexity of the humidifier and the number of individual parts.

[0021] In an advantageous embodiment of the humidifier, the housing comprises a body open at both ends transversely to the longitudinal direction and two end caps. The housing body is thus tubular, with a cross-section that can be round, oval, polygonal, rhombic, rectangular, or square. The housing body is then hermetically sealed at each end by means of the end caps. Advantageously, the housing body and the respective end caps can be screwed together. Alternatively, the housing can comprise a body open at one end transversely to the longitudinal direction and a end cap. The housing body is thus pot-shaped or bucket-shaped, with a cross-section that can be round, oval, polygonal, rhombic, rectangular, or square transversely to the longitudinal direction. The housing body is hermetically sealed at each end by means of the end caps.Advantageously, the housing body and the closing cover can be screwed together.

[0022] Advantageously, the humidifier can have an elastic circumferential seal for the respective end cap, with the circumferential seal being arranged to seal between the housing body and the respective end cap – for example, by clamping and / or pressing it in place. The circumferential seal can, for example, be made of a hardened adhesive compound.

[0023] Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the associated description of the figures based on the drawings.

[0024] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0025] Preferred embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0026] They show, each schematically Fig. 1 is an exploded view of a humidifier according to the invention in a first embodiment; Fig. 2 is a view of the humidifier according to the invention in the first embodiment; Figs. 3 to 5 are sectional views of the humidifier according to the invention in the first embodiment in three different mutually perpendicular planes; Fig. 6 is a view of an arrangement consisting of a membrane stack and a support frame of the humidifier according to the invention in the first embodiment; Fig. 7 is a view of the humidifier according to the invention in a second embodiment; Figs. 8 and 9 are sectional views of the humidifier according to the invention in the second embodiment in two different mutually perpendicular planes; Fig. 10 is a view of a housing body of the humidifier according to the invention in the second embodiment; Fig. 11 is a view of the housing body made of Fig. 10 with the arrangement consisting of the membrane stack and the support frame; Fig. 12 a view of an arrangement consisting of the membrane stack and the differently designed support frame of the humidifier according to the invention.

[0027] Fig. 1 Figure 1 shows an exploded view of a humidifier 1 according to the invention in a first embodiment. The humidifier 1 is designed to humidify dry cathode supply air K-ZL by means of moist cathode exhaust air K-AL in a fuel cell system (not shown here). The humidifier 1 comprises a housing 2, which in the first embodiment of the humidifier 1 consists of a housing body 3 open on one side, or a pot-shaped or bucket-shaped housing body, and a closing lid 3a. The pot-shaped or bucket-shaped housing body 3 and the closing lid 3a are screwed together by means of several screws 4. An elastic circumferential seal 5a – for example, made of a hardened adhesive compound – is also clamped or pressed between the housing body 3 and the closing lid 3a. An interior chamber 6 is formed in the housing 2.

[0028] The humidifier 1 also features a membrane stack 7 consisting of several membranes 8 – for clarity, only individual membranes 8 within the membrane stack 7 are shown here and subsequently – wherein the membrane stack 7 is inserted into a two-part support frame 9, and the support frame 9 is inserted into the interior 6 of the housing 2. The two-part support frame 9 can have interlocking teeth along a connecting line between the two parts to enable a secure, positive-locking connection between the two parts of the support frame 9. However, it is also conceivable that the two parts of the support frame 9 are firmly connected to each other in a different manner. Elastic ring seals 10a and 10b – for example, made of a hardened adhesive compound – are arranged to seal between the support frame 9 and the housing 2. The membrane stack 7 can be inserted longitudinally LR into the housing 2.The pot-shaped housing body 3 is oriented longitudinally LR, and the closing cover 3a closes the housing body 3 transversely to the longitudinal direction LR. The membrane stack 7 is cuboidal, with one longitudinal axis and the longest edges of the membrane stack 7 oriented longitudinally LR. The membrane stack 7 has six pairs of opposing side surfaces 11a and 11b, 12a and 12b, and 13a and 13b.

[0029] The membranes 8 are designed as foil-like flat membranes and are stacked transversely to the longitudinal direction LR in the membrane stack 7, spaced apart from each other. Supply air channels and exhaust air channels are formed between the membranes 8.

[0030] The supply air ducts are assigned to a supply air flow path 11a and connect the opposing side surfaces 12a and 12b of the membrane stack 7, which are oriented transversely to the longitudinal direction LR, by means of an air-conducting connection. The exhaust air ducts are assigned to an exhaust air flow path 11b and connect the opposing side surfaces 13a and 13b of the membrane stack 7, which are oriented parallel to the longitudinal direction LR, by means of an air-conducting connection. The supply air ducts of supply air flow path 11a are airtightly separated from the side surfaces 13a and 13b, and the exhaust air ducts of exhaust air flow path 11b are airtightly separated from the side surfaces 12a and 12b. The opposing and parallel-axis oriented side surfaces 14a and 14b of the membrane stack 7 are sealed airtight by sealing plates 15a and 15b of the support frame 9.The membranes 8 are airtight and permeable to water vapor, so that the cathode supply air K-ZL and the cathode exhaust air K-AL flow through the membrane stack 7 without mixing, and the cathode supply air K-ZL is humidified by the cathode exhaust air K-AL via the membranes 8.

[0031] The moist cathode exhaust air K-AL in exhaust air flow path 11b tends to have a higher pressure drop than the dry cathode supply air K-ZL in supply air flow path 11a due to water condensation. In humidifier 1, supply air flow path 11a is oriented longitudinally (LR) and cathode supply air K-ZL flows through it in the longitudinal direction (LR). Exhaust air flow path 11b is oriented transversely to the longitudinal direction (LR) and cathode exhaust air K-AL flows through it transversely to the longitudinal direction (LR). The flowable side surfaces 13a and 13b have a larger geometric area than the flowable side surfaces 12a and 12b. Furthermore, the exhaust air flow path 11b within the membrane stack 7 is shorter than the supply air flow path 11a within the membrane stack 7. This allows the pressure loss in the wet cathode exhaust air K-AL, which tends to lose pressure, to be reduced.Since the dry cathode supply air does not tend to cause any pressure loss, the smaller geometric area of ​​the flowable side surfaces 12a and 12b and the larger supply air flow path 11a within the membrane stack 7 are uncritical.

[0032] Between the respective flowable side surfaces 12a and 12b and the housing 2, an air chamber 16a and 16b, respectively, is formed for supplying and exhausting the cathode supply air K-ZL and cathode exhaust air K-AL, respectively. Between the respective flowable side surfaces 13a and 13b and the housing 2, an air chamber 17a and 17b, respectively, is formed for supplying and exhausting the cathode exhaust air K-AL, respectively. The housing 2 also has four air ports 18 that lead into the respective air chambers 16a and 16b, and 17a and 17b. The cathode supply air K-ZL and the cathode exhaust air K-AL can flow into or out of the air chambers 16a and 16b, and 17a and 17b, respectively, via the air ports 18. The respective air chambers 17a and 17b are sealed from each other by sealing ribs 19a and 19b, which are formed on the sealing plates 15a and 15b and aligned longitudinally LR. The air chambers 16a and 16b are sealed from the adjacent air chambers 17a and 17b by the ring seals 10a and 10b.Sealing the air chambers 16a and 16b, 17a and 17b from each other is therefore particularly simple. In particular, conventional sealing windows in the housing 2 can be dispensed with, and the number of undercuts and slides required during the manufacture of the housing can be reduced.

[0033] Fig. 2 shows a view of the humidifier 1 in the first embodiment. Fig. 3 Figure 1 shows a sectional view of the humidifier 1 in the first embodiment in a plane that is aligned parallel to individual membranes 8 and parallel to the longitudinal direction LR. Fig. 4 Figure 1 shows a sectional view of the humidifier 1 in the first embodiment in a plane that is oriented transversely to individual membranes 8 and parallel to the longitudinal direction LR. Fig. 5 Figure 1 shows a sectional view of the humidifier 1 in the first embodiment in a plane that is oriented transversely to the longitudinal direction LR.

[0034] Referring to Fig. 2 und Fig. 3 The top-shaped housing body 3 is screwed to the closing cover 3a by means of the screws 4. Referring to Fig. 3 The circumferential seal 5a is clamped between the housing body 3 and the closing cover 3a, so that the housing body 3 is airtight to the outside. In addition, the two ring seals 10a and 10b are clamped tightly between the support frame 9 and the housing 2. Specifically, ring seal 10a is clamped between the support frame and the closing cover 3a, and ring seal 10b is clamped between the support frame 9 and the housing body or a base of the housing body 3. The ring seals 10a and 10b provide an airtight separation between the air chambers 16a and 16b and the adjacent air chambers 17a and 17b.

[0035] Referring to Fig. 4 und Fig. 5 The sealing ribs 19a and 19b lie airtight against the housing 2 and the housing body 3, respectively, and seal the air chambers 17a and 17b airtight from each other. The sealing effect is enhanced by the fact that, during operation of the humidifier 1, the internal operating pressure BD presses the sealing ribs 19a and 19b against the housing 2 and the housing body 3, respectively, within the membrane stack 7, creating a seal, as indicated by the arrows. During operation of the humidifier 1, the flexible membranes 8 deform under pressure, and the membrane stack 7 inflates outwards. This presses the sealing ribs 19a and 19b against the housing 2 and the housing body 3, respectively, thus reinforcing the sealing effect. It is understood that the change in shape of the membrane stack 7 described here is small and does not cause any change in the function and structure of the membrane stack 7 and / or the humidifier 1.

[0036] Fig. 6 Figure 1 shows a view of the membrane stack 7, which is inserted into the support frame 9 of the humidifier 1 in the first embodiment. Fig. 6 It is particularly evident that the flowable side surfaces 12a and 12b, 13a and 13b remain permeable through the support frame 9. The non-flowable side surfaces 14a and 14b are sealed airtight by the sealing plates 15a and 15b. The respective ring seals 10a and 10b run along the edges of their corresponding side surfaces 12a and 12b.

[0037] Fig. 7 shows a view of the humidifier 1 according to the invention in a second embodiment. Fig. 8 shows a sectional view of the humidifier 1 in the second embodiment in a plane that is aligned parallel to individual membranes 8 and parallel to the longitudinal direction LR. Fig. 9 shows a sectional view of the humidifier 1 in the second embodiment in a plane that is oriented transversely to individual membranes 8 and parallel to the longitudinal direction LR.

[0038] In contrast to the first embodiment of humidifier 1, the humidifier 1 in the second embodiment has a differently designed housing 2. In the second embodiment of humidifier 1, the housing 2 has a tubular housing body 3 that is open at both ends. As already explained for the first embodiment, the housing body 3 is hermetically sealed on one side by means of the closing cover 3a and the circumferential seal 5a. Similarly, the housing body 3 is hermetically sealed on the other side by means of a closing cover 3b and a circumferential seal 5b. The closing covers 3a and 3b are screwed to the housing body 3 by means of the screws 4, with the circumferential seals 5a and 5b being clamped between the closing covers 3a and 3b and the housing body 3. Otherwise, the humidifiers 1 in the first and second embodiments are identical.For this reason, further explanations of the second embodiment are omitted and reference is made to the above statements. Fig. 1-6 taken.

[0039] Fig. 10 Figure 1 shows a view of the housing body 3 of the humidifier 1 according to the invention in the second embodiment. Here, the circumferential seals 5a and 5b are already mounted in provided grooves of the housing body 3. Fig. 11 shows a view of the housing body 3 from Fig. 10 with the membrane stack 7 and the support frame 9. Here, the membrane stack 7 is already inserted into the support frame 9, and the ring seals 10a and 10b are mounted in the provided grooves of the support frame 9. The support body 9 with the inserted membrane stack 7 is inserted into the housing body 3.

[0040] Fig. 12Figure 1 shows a view of an arrangement consisting of the membrane stack 7 and the differently designed support frame 9 of the humidifier 1 according to the invention. The support frame 9 is here formed in four parts. Specifically, the support frame 9 is divided into two frames surrounding the side surfaces 12a and 12b and the two sealing plates 15a and 15b. The individual parts of the four-part support frame 9 can be positively connected to one another, for example, by means of an interlocking mechanism. However, it is also conceivable that the two parts of the support frame 7 are connected to one another in a different manner.

Claims

1. Humidifier (1) for humidifying a dry cathode supply air (K-ZL) by means of a humid cathode exhaust air (K-AL) in a fuel cell system, - wherein the humidifier (1) has a housing (2) with a housing interior (6) and a membrane stack (7) arranged in the housing interior (6), - wherein the membrane stack (7) has six side surfaces (12a, 12b, 13a, 13b, 14a, 14b) and can be inserted into the housing interior (6) of the housing (2) in the longitudinal direction (LR), - wherein two of the opposing side surfaces (14a, 14b) of the membrane stack are hermetically sealed, - wherein dry cathode supply air (K-ZL) can flow through two further of the opposing side surfaces (12a, 12b) of the membrane stack (7) in a supply air flow path (11a) and humid cathode exhaust air (K-AL) can flow through two further of the opposing side surfaces (13a, 13b) of the membrane stack (7) in an exhaust air flow path (11b) without mixing, and - wherein an air chamber (16a, 16b, 17a, 17b) is formed between each of the side surfaces (12a, 12b, 13a, 13b) of the membrane stack (7) through which air can flow and the housing (2) for supplying or discharging the cathode supply air (K-ZL) in the supply air flow path (11a) or for supplying or discharging the cathode exhaust air (K-AL) in the exhaust air flow path (11b) to / from the membrane stack (7), - wherein two of the side surfaces (12a, 12b) of the membrane stack (7) through which air can flow are aligned transversely to the longitudinal direction (LR) and air can flow therethrough in longitudinal direction (LR) and wherein two other of the side surfaces (13a, 13b) of the membrane stack (7) through which air can flow are aligned parallel to the longitudinal direction (LR) and air can flow therethrough transversely to the longitudinal direction (LR), and wherein the side surfaces (14a, 14b) of the membrane stack (7) through which air cannot flow are aligned parallel to the longitudinal direction (LR), wherein the humidifier has two opposing sealing plates (15a, 15b), wherein the sealing plates (15a, 15b) bears against the side surfaces (14a, 14b) of the membrane stack (7) through which air cannot flow, characterised in that - the humidifier (1) has a support frame (9), wherein the membrane stack (7) is inserted into the support frame (9) and the support frame (9) is inserted into the housing (2), - the side surfaces (12a, 12b, 13a, 13b) of the membrane stack (7) through which air can flow are connected through the supporting frame (9) to the associated air chambers (16a, 16b, 17a, 17b) in an air-guiding manner, - the membrane stack (7) is sealed to the housing (2) via the support frame (9), - the respective sealing plates (15a, 15b) are moulded on the support frame (9), - the respective sealing plate (15a, 15b) of the support frame (9) is connected to the associated side surface (14a, 14b) of the membrane stack (7) in a material-locking and hermetic manner and bears against the housing (2) in a sealing manner, so that as a result the air chambers (17a, 17b), which are associated with the two side surfaces (13a, 13b) through which air can flow and which are aligned parallel to the longitudinal direction (LR), are hermetically separated from one another transversely to the direction of circulation around the longitudinal direction (LR), - the humidifier (1) has two elastic annular seals (10a, 10b), wherein the respective annular seal (10a, 10b) runs around the edge of the respective side surface (12a, 12b) of the membrane stack (7) through which air can flow and which is arranged transversely to the longitudinal direction (LR), and - the respective annular seal (10a, 10b) is arranged between the housing (2) and the support frame (9) in a sealing manner and thereby seals the air chamber (16a, 16b) associated with this side surface (12a, 12b) from the adjacent air chambers (17a, 17b).

2. Humidifier according to claim 1, characterised in that the membrane stack (7) is cuboidal, wherein a longitudinal axis of the membrane stack (7) and longest edges of the membrane stack (7) are aligned parallel to the longitudinal direction (LR).

3. Humidifier according to claim 1 or 2, characterised in that - that the side surfaces (12a, 12b) through which air can flow and which are aligned transversely to the longitudinal direction (LR) are associated with the supply air flow path (11a), so that the supply air flow path (11a) is aligned in longitudinal direction (LR) and cathode supply air (K-ZL) can flow therethrough in longitudinal direction (LR), and - the side surfaces (13a, 13b) through which air can flow and which are aligned parallel to the longitudinal direction (LR) are associated with the exhaust air flow path (11b), so that the exhaust air flow path (11b) is aligned transversely to the longitudinal direction (LR) and cathode exhaust air (K-AL) can flow therethrough transversely to the longitudinal direction (LR).

4. Humidifier according to any one of the preceding claims, characterised in that - the membrane stack (7) has multiple flexible membranes which are deformable when a pressure acts on them, and the respective sealing plate (15a, 15b) is designed in such a way that, during operation of the humidifier (1), the respective sealing plate (15a, 15b) can be deformed by the internal operating pressure (BD) in the membrane stack (7), which is higher than the external pressure, and can be pressed against the housing (2) in a sealing manner, and / or - the membrane stack (7) has multiple flexible membranes which are deformable when a pressure acts on them, and the respective sealing plate (15a, 15b) is designed to be deformable, so that when the internal operating pressure (BD) in the membrane stack (7) is higher than the external pressure, the respective sealing plate (15a, 15b) can be pressed against the housing (2) in a sealing manner.

5. Humidifier according to any one of the preceding claims, characterised in that - at least one sealing rib (19a, 19b) aligned in longitudinal direction (LR) is formed on the respective sealing plate (15a, 15b) and the respective sealing rib (19a, 19b) bears in a sealing manner against the housing (2), so that the air chambers (17a, 17b), which are associated with the two side surfaces (13a, 13b) through which air can flow and which are aligned parallel to the longitudinal direction (LR), are separated from one another in an airtight manner transversely to the direction of circulation.

6. Humidifier according to claim 5, characterised in that the membrane stack (7) has multiple flexible membranes which are deformable when a pressure acts on them, and the respective sealing plate (15a, 15b) or the respective sealing rib (19a, 19b) is formed on the sealing plate (15a, 15b) in such a way that the respective sealing plate (15a, 15b) can be deformed during operation of the humidifier (1) by the internal operating pressure (BD) in the membrane stack (7), which is higher than the external pressure, and the respective sealing plate (15a, 15b) or the respective sealing rib (19a, 19b) can be pressed against the housing (2) in a sealing manner.

7. Humidifier according to any one of the preceding claims, characterised in that - the housing (2) has a housing body (3) open on both sides transversely to the longitudinal direction (LR) and two closing covers (3a, 3b), wherein the housing body (3) is closed axially at the longitudinal end by means of the closing covers (3a, 3b), or - the housing (2) has a housing body (3) open on one side transversely to the longitudinal direction (LR) and a closing cover (3a), wherein the housing body (3) is closed axially at the longitudinal end by means of the closing cover (3a).

8. Humidifier according to claim 7, characterised in that the humidifier (1) has an elastic rotary seal (5a, 5b) for the respective closing cover (3a, 3b), wherein the rotary seal (5a, 5b) is arranged in a sealing manner between the housing body (3) and the respective closing cover (3a, 3b).

9. Humidifier according to claim 1 and / or 8, characterised in that the respective annular seal (10a, 10b) and / or the respective rotary seal (5a, 5b) are formed from a hardened adhesive compound.