Air humidifier for a fuel cell system

Abstract

The invention relates to an air humidifier (1) for transferring moisture from a moist exhaust air stream (3) to a dry supply air stream (2), - comprising a humidifier block (4), through which the exhaust air stream (3) and the supply air stream (2) can flow media-separately and which in the process transfers moisture from the exhaust air stream (3) to the supply air stream (2), and - comprising a housing (5) in which the humidifier block (4) is located. Water separation (20) from the exhaust air stream (3) can be improved in that a membrane (18) through which the exhaust air stream (3) can flow and which separates water from the exhaust air stream (3) is located in the housing (5).

Description

[0001] 100A23010WG

[0002] December 3, 2025

[0003] 1

[0004] humidifier

[0005] The present invention relates to an air humidifier for transferring moisture from a moist exhaust air stream to a dry supply air stream for a fuel cell system, in particular of a motor vehicle.

[0006] For an optimized fuel cell process, it is advantageous to humidify the supply air stream fed to the cathode side of the respective fuel cell, i.e., to increase the proportion of gaseous and vaporous water. Since water is produced on the cathode side anyway during the fuel cell process, the exhaust air stream from the cathode side of the respective fuel cell contains a comparatively high amount of moisture, i.e., water in the form of gas, vapor, and droplets. The moisture from the exhaust air stream can be used effectively to humidify the supply air stream. For this purpose, a humidifier of the type mentioned above is used. Depending on the operating state of the fuel cell system, the humid exhaust air stream may even contain liquid water, which can be detrimental to the humidifier. Furthermore, the dehumidified exhaust air stream may still contain liquid water, which can also be disadvantageous.For example, liquid water can freeze at low ambient temperatures, which can cause air-carrying lines in a fuel cell system equipped with a humidifier to freeze and become blocked. Furthermore, a fuel cell system may be equipped with a turbocharger whose compressor is located in the intake air stream and whose turbine is located in the exhaust air stream. Such a turbine can be damaged by water droplets.

[0007] The present invention addresses the problem of providing an improved or at least a better humidifier of the type described above. 03.12.2025

[0008] 2. Another embodiment is to be specified, which is characterized in particular by improved separation of liquid water from the exhaust air stream. At the same time, an embodiment is sought which is accompanied by a low pressure loss during the flow through the humidifier.

[0009] This problem is solved according to the invention by the subject matter of the independent claim. Advantageous embodiments are the subject matter of the dependent claims.

[0010] The invention is based on the general concept of providing a membrane within the housing of the humidifier for separating water from the exhaust air stream. This membrane is permeable to the exhaust air stream and is configured to at least partially separate the water carried in the exhaust air stream as it passes through it. In other words, as the air flows through the membrane, it removes at least some of the water contained in the exhaust air stream. This significantly reduces the water content in the exhaust air stream downstream of the membrane. The flow through the membrane inevitably results in a flow resistance, which leads to an increase in back pressure within the humidifier. However, this increase in back pressure can be largely compensated for by a surprising additional effect of the membrane: the flow through the membrane laminars the exhaust air stream.Upstream of the membrane, the exhaust airflow is largely turbulent. As the air flows through the membrane, the exhaust airflow is calmed, resulting in a largely laminar flow downstream. This reduces the flow resistance in the exhaust airflow downstream of the membrane. This leads to a decrease in back pressure, which counteracts and largely compensates for the increase in back pressure at the membrane. 03.12.2025.

[0011] 3

[0012] Specifically, the invention proposes equipping the humidifier with a humidifier block through which the exhaust air stream and the supply air stream can flow separately, thereby transferring moisture from the exhaust air stream to the supply air stream. Furthermore, the humidifier comprises a housing in which the humidifier block is arranged, and which has a longitudinal direction, a transverse direction, and a vertical direction that are perpendicular to one another. The housing also has an exhaust air inlet for supplying the moist exhaust air stream to the humidifier block, an exhaust air outlet for removing the dehumidified exhaust air stream from the humidifier block, a supply air inlet for supplying the dry supply air stream to the humidifier block, and a supply air outlet for removing the humidified supply air stream from the humidifier block. According to the invention, a membrane through which the exhaust air stream flows is arranged in the housing for separating water from the exhaust air stream.This membrane is arranged in the housing in such a way that it is subjected to the exhaust air flow during operation of the humidifier.

[0013] Such a humidifier block can be formed, for example, using membranes that are permeable to moisture or water but essentially impermeable to air. In this context, the terms "moist," "dry," "dehumidified," and "humidified" are to be understood relatively, such that the dehumidified exhaust air contains less moisture than the moist exhaust air, and the humidified supply air contains more moisture than the dry supply air.

[0014] According to an advantageous embodiment, the membrane can be configured to be impermeable to liquid water and permeable to air or exhaust air. This allows the membrane to separate liquid water, i.e., drops and droplets, from the exhaust air stream, while remaining permeable to gaseous water. This differs from the membrane described on December 3, 2025.

[0015] 4

[0016] Water separation, which is permeable to exhaust air, from the membranes of the humidifier block, which are impermeable to exhaust air.

[0017] In the present context, a “configuration” corresponds to a “design” and / or a “setup”, so that the phrase “configured so that” is synonymous with the phrase “designed so that” and / or “set up so that”.

[0018] According to an advantageous embodiment, the membrane can be designed to be hydrophobic either entirely or at least on its upstream side. In particular, the membrane can consist entirely or at least on its upstream side of a hydrophobic material. Alternatively, the membrane can be provided with a hydrophobic coating either entirely or at least on its upstream side. In particular, the membrane can be provided with a coating of a hydrophobic material either entirely or at least on its upstream side. Hydrophobic materials include, for example, fluoropolymers, especially polytetrafluoroethylene or C6 fluoropolymers.

[0019] According to an advantageous embodiment, the membrane may be or comprise a grid, a mesh, a fibrous body, a filter body, or a nonwoven fabric. The grid, mesh, fibrous body, filter body, or nonwoven fabric may have a pore structure that is permeable to exhaust air and impermeable to water, particularly liquid water. 03.12.2025

[0020] 5

[0021] According to an advantageous embodiment, the membrane may have a pore structure with a maximum pore size of 250 pm. In particular, the pore size may be a maximum of 200 pm, 150 pm, 100 pm, or 50 pm.

[0022] According to an advantageous embodiment, the membrane can be arranged in a space through which the exhaust air stream flows, and which is connected to a water collection chamber by means of a wall opening. Furthermore, the membrane can advantageously be arranged in the exhaust air stream downstream of the wall opening, in particular such that water deposited on the membrane can flow from the space through the wall opening into the water collection chamber. This provides a way to drain the water from the humidifier.

[0023] Preferably, the room can be an exhaust air extraction room that draws the exhaust air stream from the humidifier block and feeds it to the exhaust air outlet. In this case, the liquid water in the humidifier block can be used to transfer moisture to the supply air stream, since it is only separated downstream of the humidifier block. In an alternative embodiment, the room can be an exhaust air supply room that draws the exhaust air stream from the exhaust air inlet and feeds it to the humidifier block. At this point, a particularly large amount of liquid water can be separated from the exhaust air stream.

[0024] According to an advantageous embodiment, the wall opening can be arranged at a transition point where the room forms or defines an exhaust air duct that directs the exhaust air flow to the exhaust air outlet. This promotes a low-pressure flow for the exhaust air stream. Advantageously, the membrane can be arranged downstream of the wall opening in the transition point. This allows for a particularly compact design, as the room in this 03.12.2025

[0025] 6

[0026] The transition has a relatively small cross-sectional area for the exhaust airflow.

[0027] In an advantageous embodiment, a stage projecting into the exhaust air stream can be formed at the transition point, reducing the cross-section through which the exhaust air stream can flow, such that at the stage a room outlet cross-section transitions into a duct inlet cross-section, the duct inlet cross-section being smaller than the room outlet cross-section. This stage allows the exhaust air stream to be used to propel the separated water towards the wall opening.

[0028] In an advantageous embodiment, the wall opening in the room can be arranged directly adjacent to the step. This improves the discharge effect of the exhaust air stream for the separated water. Additionally or alternatively, the membrane in the exhaust air discharge duct can be arranged directly adjacent to the step. This results in a particularly compact humidifier, as the membrane only needs to cover or fill a small cross-section, namely the duct inlet cross-section.

[0029] In another embodiment, the membrane can extend transversely to the housing height direction and rise towards the wall opening. This allows the exhaust airflow to be used to drive the water that accumulates on the membrane's upstream side, from the membrane towards the wall opening. The membrane can be configured to be flat, extending in a plane or within a single membrane plane. Alternatively, the membrane can be curved, preferably convexly curved, and have a correspondingly curved membrane surface or geometry. 03.12.2025

[0030] 7

[0031] A further development proposes that the membrane fill or close off, preferably completely, the cross-section through which the exhaust air flows downstream of the wall opening. This prevents the airflow from bypassing the membrane, forcing the entire exhaust airflow to pass through it. This increases the efficiency of the membrane's separation action.

[0032] In a preferred embodiment, a deflection zone can be formed within the space, creating a flow curve and redirecting the exhaust airflow. In particular, the deflection zone can redirect the exhaust airflow with respect to a deflection axis that, for example, extends parallel to the longitudinal direction of the housing. Such a flow deflection generates inertial forces that prevent the entrained water from following the deflection as well as the exhaust airflow. The water can therefore condense in the deflection zone on the wall that limits the deflection zone on the outside of the curve. Investigations by the applicant have shown that, particularly in a deflection zone, an inhomogeneous flow can develop due to the inertial effect. In a region located relatively close to a deflection axis around which the supply airflow is redirected in the deflection zone, a comparatively small volume flow rate occurs.A comparatively low flow velocity prevails. In contrast, a significantly higher volume flow rate and / or flow velocity occur in an area further away from the deflection axis. Thus, the supply air flow within the deflection area is inhomogeneous with respect to its flow direction, both in terms of flow velocity and volume flow rate per unit cross-section. The membrane and the wall opening can now be positioned within the deflection area. It has been shown that this improves water separation. 03.12.2025.

[0033] 8

[0034] According to an advantageous embodiment, the deflection area can be configured to redirect the exhaust airflow with respect to a deflection axis running parallel to the longitudinal direction of the housing, with the wall opening bordering the membrane on a side facing away from the deflection axis. This allows the exhaust airflow to drive the separated water particularly effectively towards the wall opening, expelling it from the room and directing it to the water collection chamber.

[0035] Additionally or alternatively, the membrane can be geometrically positioned within the housing between the deflection axis and the wall opening. This measure promotes water separation.

[0036] In an advantageous embodiment, the deflection area can be configured to deflect the exhaust airflow by at least 45° with respect to a deflection axis running parallel to the longitudinal direction of the housing, so that the exhaust airflow in the exhaust air discharge chamber flows away from the water collection chamber from the wall opening onwards. While the gaseous exhaust airflow can easily follow this flow deflection, the liquid water droplets carried in the exhaust airflow cannot follow this flow deflection due to their greater mass. In this way, condensation of the carried water on the partition wall or on the aforementioned side wall in the deflection area is promoted, so that a relatively large amount of water can be supplied to the wall opening. In particular, the deflection area can be configured to deflect the exhaust airflow by approximately 90° with respect to the deflection axis.For example, the exhaust airflow can flow parallel to the transverse direction of the housing towards the wall opening and, after being deflected in the deflection area, flow essentially parallel to the vertical direction of the housing away from the wall opening to the exhaust air outlet. 03.12.2025.

[0037] 9

[0038] In the advantageous embodiment, the partition wall can extend in a curved shape in the deflection area to assist in redirecting the exhaust airflow. A curved partition wall, or a curved section of the partition wall, promotes low-resistance flow deflection, which reduces the pressure drop in the exhaust airflow as it passes through the humidifier. For example, the partition wall can be concavely curved in the deflection area towards the exhaust air discharge chamber.

[0039] Another advantageous embodiment proposes that the partition wall, from the outlet side of the humidifier block where the dehumidified exhaust air exits, has a distance measured in the housing height direction. This distance can then increase along the outlet side of the humidifier block in the direction of airflow that the exhaust air has in the exhaust air duct. In this way, a pressure drop in the exhaust air stream is reduced. The volume of the exhaust air stream increases along the outlet side in the direction of flow. Since the distance also increases along the outlet side, a larger cross-sectional area is available for the increasing volume flow, thus enabling a homogeneous exhaust air stream characterized by a low pressure drop.

[0040] 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.

[0041] 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 individually, without departing from the scope of the invention. The aforementioned and subsequently mentioned components of a higher-level unit, such as 03.12.2025

[0042] 10. Parts of a device, apparatus or arrangement that are separately designated may form separate parts or components of this unit or be integral areas or sections of this unit, even if this is shown differently in the drawings.

[0043] 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.

[0044] They show, schematically,

[0045] Figure 1 shows a highly simplified, schematic sectional view of a humidifier in the area of ​​a water collection chamber.

[0046] Figures 2 and 3 each show a schematic diagram of a fuel cell system with an air humidifier in two alternative embodiments.

[0047] As shown in Figures 1 to 3, a humidifier 1, which serves to transfer moisture from a moist exhaust air stream 3 to a dry supply air stream 2 for a fuel cell system 32 (simplified in Figures 2 and 3), in particular a motor vehicle (not shown here), comprises a humidifier block 4. The humidifier block 4 is media-separated from the exhaust air stream 3 and the supply air stream 2 of the fuel cell system 32 and is configured such that moisture, i.e., water, is transferred from the exhaust air stream 3 to the supply air stream 2 during the flow through the humidifier block 4. The humidifier 1 also has a housing 5 in which the humidifier block 4 is located.

[0048] The housing 5 is arranged as shown in Figure 1. The housing 5 defines a longitudinal direction X, a transverse direction Y, and a vertical direction Z, all of which are perpendicular to each other. In Figure 1, the longitudinal direction X is perpendicular to the plane of the drawing. The transverse direction Y extends substantially horizontally in Figure 1, while the vertical direction Z extends substantially vertically.

[0049] According to Figures 2 and 3, the fuel cell system 32 comprises a fuel cell stack 33, to which the humidified supply air stream 2 is fed during operation, and from which the humid exhaust air stream 3 is discharged during operation. The fuel cell system 32 can include a turbocharger 34, which is conventionally equipped with a turbine 35 and a compressor 36, which are connected to each other via a drive shaft 37. The turbine 35 is integrated into the exhaust air stream 3 downstream of the humidifier 1. The compressor 36 is integrated into the supply air stream 2 upstream of the humidifier 1.

[0050] The housing 5 of the humidifier 1 has, according to figures 1 to 3, an exhaust air inlet 8 for supplying the moist exhaust air stream 3 to the humidifier block 4, an exhaust air outlet 9 for removing the dehumidified exhaust air stream 3 from the humidifier block 4, an air inlet 6 for supplying the dry air stream 2 to the humidifier block 4 and an air outlet 7 for removing the humidified air stream 2 from the humidifier block 4.

[0051] In the humidifier 1 presented here, a membrane 18, through which the exhaust air stream 3 flows, is arranged in the housing 5 for separating water from the exhaust air stream 3. This membrane is shown in simplified form in Figures 1 to 3. The membrane 18 separates water carried in the exhaust air stream 3, preferably liquid water, and in particular droplet-shaped water, from the exhaust air stream 3. (03.12.2025)

[0052] 12

[0053] Water separation is indicated by an arrow in Figure 1 and labelled 20.

[0054] According to Figure 2, the membrane 18 in the housing 5 can be arranged downstream of the humidifier block 4 with respect to the exhaust air flow 3, i.e., with respect to the direction of the exhaust air flow 3, between the humidifier block 4 and the exhaust air outlet 9. Alternatively, according to Figure 3, the membrane 18 in the housing 5 can be arranged upstream of the humidifier block 4 with respect to the exhaust air flow 3, i.e., with respect to the direction of the exhaust air flow 3, between the humidifier block 4 and the exhaust air inlet 8. In the example of Figure 1, the membrane 18 is located downstream of the humidifier block 4, i.e., as shown in Figure 2, downstream of the humidifier block 4 with respect to the exhaust air flow 3 in the housing 5.

[0055] Advantageously, the membrane 18 is configured to be impermeable to liquid water and permeable to air. Thus, the membrane 18 separates liquid water, i.e., drops and droplets, from the exhaust air stream 3, while remaining permeable to gaseous water. Furthermore, the membrane 18 can advantageously be designed to be hydrophobic either entirely or at least on its upstream side 19. In particular, the membrane 18 can have a hydrophobic coating 22 either entirely or at least on its upstream side 19. The coating can consist of a hydrophobic material.

[0056] Membrane 18 can be or have a grid, mesh, fibrous body, filter body, or nonwoven body having a pore structure that is permeable to exhaust air and impermeable to water, especially liquid water. Particularly advantageously, Membrane 18 can have a pore structure with a pore size in the range of 1 pm to 250 pm. 03.12.2025

[0057] 13

[0058] In the example shown in Figure 1, the membrane 18 is arranged in a space 11 through which the exhaust air stream 3 flows. This space 11 is formed in the housing 5 and is connected to a water collection chamber 12 by means of a wall opening 16. The membrane 18 is advantageously arranged in the exhaust air stream 3 downstream of the wall opening 16, in particular such that water separated on the membrane 18 can flow from the space 11 through the wall opening 16 into the water collection chamber 12, as indicated by the arrow of the water separation 20.

[0059] According to Figures 1 and 2, the chamber 11 in which the membrane 18 is arranged can be an exhaust air discharge chamber 11'. The exhaust air discharge chamber 11' directs the exhaust air stream 3 from the humidifier block 4 to the exhaust air outlet 9. In this case, the liquid water in the humidifier block 4 can be used to transfer moisture to the supply air stream 2, since it is only separated downstream of the humidifier block 4. In the alternative embodiment shown in Figure 3, however, the chamber 11 in which the membrane 18 is arranged can be an exhaust air supply chamber 11'. The exhaust air supply chamber 11' directs the exhaust air stream 3 from the exhaust air inlet 8 to the humidifier block 4. At this point, a particularly large amount of liquid water can be separated from the exhaust air stream 3. However, the embodiment shown in Figures 1 and 2 is preferred, in which the membrane 18 is arranged in the exhaust air discharge chamber 11 ', i.e. downstream of the humidifier block 4.

[0060] According to Figure 1, the exhaust air discharge chamber 11' can be formed on the lower side 10 of the housing 5 with respect to the housing height direction Z. Furthermore, the water collection chamber 12 is formed on the lower side 10 of the housing 5 below the exhaust air discharge chamber 11' with respect to the housing height direction Z. This water collection chamber 12 can have a water drain opening 13 for discharging water collected in the water collection chamber 12 and is separated from the exhaust air discharge chamber 1T by a partition wall 14. The exhaust air discharge chamber 1T 03.12.2025

[0061] 14 has a deflection section 15 between the humidifier block 4 and the exhaust air outlet 9, which is configured to deflect the exhaust air flow 3. In the embodiment shown here, the exhaust air flow 3 flows essentially horizontally, from left to right in the transverse direction Y of the housing, up to the deflection section 15. From the deflection section 15 onwards, the exhaust air flow 3 flows essentially vertically, from bottom to top in the vertical direction Z of the housing.

[0062] As shown in Figure 1, the partition 14 has a wall opening 16 in the deflection area 15, which fluidically connects the water collection chamber 12 with the exhaust air discharge chamber 1T. During operation of the humidifier 1, the exhaust air stream 3 does not flow through the water collection chamber 12, creating a dead space 17 in the area of ​​the wall opening 16. Water that condenses on the partition 14 is carried by the exhaust air stream 3 to the wall opening 16 and passes through it into the water collection chamber 12. This already contributes to the water separation 20.

[0063] The exhaust air discharge chamber 1T is bounded below the humidifier block 4 and in the deflection area 15 on the inlet side in the housing height direction Z by the partition wall 14. Furthermore, the exhaust air discharge chamber 1T is bounded in the deflection area 15 and subsequently in the direction of the exhaust air outlet 9 transversely to the housing height direction Z, preferably in the housing transverse direction Y, by a side wall 31 of the housing 5.

[0064] According to an advantageous embodiment, the room 11 has an exhaust air discharge duct 30 on the outlet side, or forms the exhaust air discharge duct 30 on the outlet side, which supplies the exhaust air flow 3 to the exhaust air outlet 9. Advantageously, the wall opening 16 can be arranged at a transition 38, which is indicated in Figure 1 by a curved bracket. In this transition 38, the room 11 transitions into the exhaust air discharge duct 30, which separates the exhaust air flow 3 from the rest of the room.

[0065] 15

[0066] The air flows from room 11 to the exhaust outlet 9. The transition 38 can be conveniently located at the outflow end of the deflection area 15.

[0067] Advantageously, a stage 23 projecting into the exhaust air stream 3 can be formed in the transition 38, which reduces the cross-section through which the exhaust air stream 3 can flow, such that at the stage 23 a room outlet cross-section 24 transitions into a duct inlet cross-section 25, the duct inlet cross-section 25 being smaller than the room outlet cross-section 24. Through this stage 23, the exhaust air stream 3 drives the separated water in the direction of the wall opening 16.

[0068] The wall opening 16 in room 11 can be conveniently located directly adjacent to stage 23. Additionally or alternatively, the membrane 18 in the exhaust air duct 30 can be located directly adjacent to stage 23. Furthermore, the membrane 18 extends transversely or inclined to the housing height direction Z and rises towards the wall opening 16. Here, the membrane 18 is configured as a plane and extends in an unspecified membrane plane.

[0069] The membrane 18 is arranged and configured such that it fills or closes, preferably completely, the cross-section through which the exhaust air stream 3 can flow downstream of the wall opening 16. In the example of Figure 1, the membrane 18 closes the exhaust air discharge duct 30 or its duct inlet cross-section 25.

[0070] The deflection area 15 is configured here such that it deflects the exhaust air flow 3 by approximately 90° with respect to a deflection axis 21 running parallel to the longitudinal direction X of the housing, such that the exhaust air flow 3 flows away from the water collection chamber 12 in the exhaust air discharge chamber 11' from the wall opening 16. In the example of Figure 1, the exhaust air flow 3 flows essentially vertically upwards after its deflection from the wall opening 16. In the example shown, the flow deflection with respect to the deflection axis 21 is shown on 03.12.2025.

[0071] 16

[0072] Oriented counterclockwise.

[0073] A certain degree of water separation 20 can already be achieved by the targeted positioning and dimensioning of the wall opening 16 in the deflection area 15. The membrane 18 significantly improves the water separation 20. For this purpose, the membrane 18 and the wall opening 16 are located in the deflection area.

[0074] 15 arranged.

[0075] The wall opening 16 is expediently arranged on a side of the room 11 facing away from the deflection axis 21 and can adjoin the membrane 18 or the step 23. Likewise, the membrane 18 can be positioned in the housing 5 such that it is geometrically located between the deflection axis 21 and the wall opening.

[0076] 16 is arranged.

[0077] According to Figure 1, the partition 14 is advantageously curved at least in the deflection area 15, such that a curved section 26 of the partition 14 supports the deflection of the exhaust air flow 3. In the examples shown, the partition 14 is concavely curved in its curved section 26, i.e., in the deflection area 15 towards the exhaust air discharge chamber 1T.

[0078] According to Figure 1, the partition 14 has a distance 28 measured in the housing height direction Z from an outlet side 27 of the humidifier block 4, where the dehumidified exhaust air stream 3 exits the humidifier block 4. In the example of Figure 1, this distance 28 increases in a flow direction 29, which the exhaust air stream 3 has in the exhaust air discharge chamber 1 T in the area of ​​the outlet side 27, along the outlet side 27 of the humidifier block 4 up to the deflection area 15. In the example of Figure 1, the flow direction 29 extends horizontally below the humidifier block 4 and from left to right in the housing transverse direction Y. In or at the deflection area 15, the distance 28 reaches 3.12.2025

[0079] 17

[0080] Figure 1 shows its maximum. There, the exhaust air stream 3 reaches its maximum volume flow rate.

[0081] *****

[0082] A23010WG .12.2025

[0083] 18

[0084] Reference symbol

[0085] humidifier

[0086] supply air flow

[0087] Exhaust air stream

[0088] humidifier block

[0089] Housing

[0090] Air intake

[0091] Air supply outlet

[0092] exhaust air inlet

[0093] exhaust air outlet

[0094] Underside of housing

[0095] Room 'Exhaust air discharge room' 'Exhaust air supply room'

[0096] Water collection chamber

[0097] Water drain opening

[0098] partition

[0099] Deflection area

[0100] Wall opening

[0101] Dead space

[0102] membrane

[0103] Upstream side

[0104] Water separation

[0105] deflection axis

[0106] coating

[0107] Level

[0108] Room outlet cross-section

[0109] Channel inlet cross-section A23010WQ 2.2025

[0110] 19

[0111] Section

[0112] Exit side

[0113] Distance

[0114] Flow direction

[0115] exhaust air discharge duct

[0116] side wall

[0117] Fuel cell system

[0118] Fuel cell stack

[0119] turbocharger

[0120] turbine

[0121] compressor

[0122] drive shaft

[0123] transition

[0124] *****

Claims

December 3, 2025 20 Claims 1. Humidifier (1) for transferring moisture from a moist exhaust air stream (3) to a dry supply air stream (2) for a fuel cell system, in particular of a motor vehicle, - with a humidifier block (4) through which the exhaust air stream (3) and the supply air stream (2) can flow separately and thereby transfers moisture from the exhaust air stream (3) to the supply air stream (2), and - with a housing (5) in which the humidifier block (4) is arranged and which has a housing longitudinal direction (X), a housing transverse direction (Y) and a housing vertical direction (Z) that are perpendicular to each other, - wherein the housing (5) has an exhaust air inlet (8) for supplying the moist exhaust air stream (3) to the humidifier block (4), an exhaust air outlet (9) for removing the dehumidified exhaust air stream (3) from the humidifier block (4), a supply air inlet (6) for supplying the dry supply air stream (2) to the humidifier block (4) and a supply air outlet (7) for removing the humidified supply air stream (2) from the humidifier block (4), and - wherein a membrane (18) through which the exhaust air stream (3) flows is arranged in the housing (5) for separating water from the exhaust air stream (3).

2. Humidifier (1) according to claim 1, characterized in that, - that the membrane (18) is configured to be impermeable to liquid water and permeable to air.

3. Humidifier (1) according to claim 1 or 2, characterized in that, December 3, 2025 21 - that the membrane (18) is hydrophobic at least on its upstream side (19).

4. Humidifier (1) according to one of the preceding claims, characterized in that - that the membrane (18) has a hydrophobic coating (22) at least on its upstream side (19).

5. Humidifier (1) according to one of the preceding claims, characterized in that - that the membrane (18) is or has a grid or a mesh or a fibrous body or a filter body or a nonwoven body.

6. Humidifier (1) according to one of the preceding claims, characterized in that - that the membrane (18) has a pore structure with a maximum pore size of 250 pm.

7. Humidifier (1) according to one of the preceding claims, characterized in that - that the membrane (18) is arranged in a space (11) through which the exhaust air stream (3) can flow, which is connected to a water collection space (12) by means of a wall opening (16).

8. Humidifier (1) according to claim 7, characterized in that - that the membrane (18) is arranged in the exhaust air stream (3) downstream of the wall opening (16). December 3, 2025 22 9. Humidifier (1) according to claim 7 or 8, characterized in that, - that the membrane (18) in the exhaust air stream (3) is arranged downstream of the wall opening (16) in such a way that water separated on the membrane (18) from the room (11) can flow through the wall opening (16) into the water collection chamber (12).

10. Humidifier (1) according to one of claims 7 to 9, characterized in that - that the room (11 ) is an exhaust air discharge room (11 ') that removes the exhaust air flow (3) from the humidifier block (4) and feeds it to the exhaust air outlet (9).

11. Humidifier (1) according to one of claims 7 to 9, characterized in that, - that the room (11 ) is an exhaust air supply room (11 “) that carries away the exhaust air flow (3) from the exhaust air inlet (8) and feeds it to the humidifier block (4).

12. Humidifier (1) according to one of claims 7 to 11, characterized in that, - that the wall opening (16) is arranged at a transition (38) in which the space (11) forms an exhaust air discharge duct (30) that directs the exhaust air flow (3) to the exhaust air outlet (9), - that the membrane (18) is arranged in the transition (38) downstream of the wall opening (16).

13. Humidifier (1) according to claim 12, characterized in that - that in the transition (38) a stage (23) projecting into the exhaust air stream (3) is formed, which has a cross-section through which the exhaust air stream (3) can flow December 3, 2025 23 reduced, such that at the step (23) a room outlet cross-section (24) transitions into a duct inlet cross-section (25), - that the channel inlet cross-section (25) is smaller than the room outlet cross-section (24).

14. Humidifier (1) according to claim 13, characterized in that - that the wall opening (16) in the room (11) is located directly at the step (23).

15. Humidifier (1) according to claim 13 or 14, characterized in that, - that the membrane (18) is located directly at the stage (23) in the exhaust air discharge duct (30).

16. Humidifier (1) according to one of claims 7 to 15, characterized in that - that the membrane (18) extends transversely to the housing height direction (Z) and rises towards the wall opening (16).

17. Humidifier (1) according to one of claims 7 to 16, characterized in that - that the membrane (18) fills a cross-section downstream of the wall opening (16) through which the exhaust air flow (3) can flow.

18. Humidifier (1) according to one of the preceding claims, characterized in that - that the membrane (18) is flat or curved, preferably convex. December 3, 2025 24 19. Humidifier (1) according to one of claims 7 to 18, characterized in that - that the room (11) has a deflection area (15) that deflects the exhaust airflow (3) around, - that the wall opening (16) and the membrane (18) are arranged in the deflection area (15).

20. Humidifier (1) according to claim 19, characterized in that - that the deflection area (15) is configured to deflect the exhaust air flow (3) with respect to a deflection axis (21) running parallel to the longitudinal direction (X) of the housing, - that the wall opening (16) is located on a side in the room (11) facing away from the deflection axis (21). *****

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