HUMIDIFIER MODULE WITH STITCHED-IN FLOW FIELD, HUMIDIFIER, METHOD FOR MAKING A HUMIDIFIER MODULE AND METHOD FOR MAKING A HUMIDIFIER

Abstract

A humidifier module is provided having a water vapor-permeable membrane having spacers defining a flow field arranged on either side of the membrane and having a yarn stitched into the membrane. The spacers defining the flow field are formed by the yarn stitched into the membrane. A humidifier, a method for making a humidifier module and a method for making a humidifier are also provided.

Claims

1. A humidifier module, comprising: a water vapor-permeable membrane having spacers defining a flow field arranged on either side of the membrane, and wherein the spacers defining the flow field are formed by a yarn stitched into the membrane.

2. The humidifier module according to claim 1, wherein the yarn extends through the membrane such that at least one yarn top piece is arranged on a first side of the membrane and at least one yarn bottom piece is arranged on a second side of the membrane.

3. The humidifier module according to claim 2, wherein the yarn or an additional yarn extends through the membrane such that one or more of the yarn top pieces and/or one or more of the yarn bottom pieces are joined together at nodal points.

4. The humidifier module according to claim 1, wherein the yarn is formed as a top thread, an additional yarn is formed as a bottom thread, and the top thread is joined to or interwoven with the bottom thread at least at one nodal point.

5. The humidifier module according to claim 3, wherein the yarn and/or the additional yarn is formed from a thermoplastic material, and at least some of the nodal points are fusible by the action of heat in order to form a seal.

6. The humidifier module according to claim 5, wherein the yarn and the additional yarn have different melting points.

7. The humidifier module according to claim 1, wherein a further yarn is stitched into a margin region of the membrane at least partly on a circumference or is applied to the margin region.

8. A humidifier having a plurality of humidifier modules according to claim 1 arranged between two end plates.

9. A method for making a humidifier module including a water vapor-permeable membrane having spacers defining a flow field arranged on either side of the membrane, wherein the spacers defining the flow field are formed by a yarn stitched into the membrane, the method comprising: providing a membrane, and stitching a yarn into or applying a yarn on the membrane such that the yarn forms a spacer defining a flow field.

10. A method for making a humidifier having a plurality of humidifier modules arranged between two end plates, each of the humidifier modules including a water vapor-permeable membrane having spacers defining a flow field arranged on either side of the membrane, wherein the spacers defining the flow field are formed by a yarn stitched into the membrane, the method comprising: providing a plurality of humidifier modules; fusing the humidifier modules together by the action of heat; arranging the plurality of fused humidifier modules between two end plates; and clamping the humidifier modules to the end plates by tie rods.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0035] Further benefits, features and details will emerge from the claims, the following detailed description, and the drawings.

[0036] FIG. 1 illustrates a schematic top view of a humidifier module.

[0037] FIG. 2 illustrates a schematic cross-sectional view of a first embodiment of a humidifier module.

[0038] FIG. 3 illustrates a schematic cross-sectional view of a second embodiment of a humidifier module.

[0039] FIG. 4 illustrates a schematic cross-sectional view of a third embodiment of a humidifier module.

[0040] FIG. 5 illustrates a schematic cross-sectional view of a fourth embodiment of a humidifier module.

[0041] FIG. 6 illustrates a humidifier.

DETAILED DESCRIPTION

[0042] Fuel cells are used for generating energy and can be employed in particular for generating energy for the propulsion of motor vehicles. In some embodiments, a multitude of fuel cells is assembled into a fuel cell stack.

[0043] Each of the fuel cells comprises an anode, a cathode as well as a proton-conductive polymer membrane separating the anode from the cathode. The polymer membrane is formed from an ionomer, such as a sulfonated tetrafluorethylene polymer (PTFE) or a polymer of perfluorinated sulfonic acid (PFSA). Alternatively, the polymer membrane can be formed as a hydrocarbon membrane.

[0044] In addition, a catalyst may be blended in with the anodes and/or the cathodes, the membrane being coated on its first side and/or on its second side with a catalyst layer consisting of a precious metal or a mixture containing precious metals such as platinum, palladium, ruthenium or the like, which serve as a reaction accelerant in the reaction of the particular fuel cell.

[0045] The anode fuel (such as hydrogen) may be supplied via an anode space. In a polymer electrolyte membrane fuel cell (PEM fuel cell), fuel or fuel components are split into protons and electrons at the anode. The PEM lets the protons through, but is impermeable to the electrons. For example, the reaction 2H.sub.2.fwdarw.4H.sup.++4e.sup.− (oxidation/electron donation) will occur at the anode. While the protons pass through the PEM and go to the cathode, the electrons are taken by an external circuit to the cathode or to an energy accumulator.

[0046] The cathode gas (such as oxygen or air containing oxygen) can be supplied to the cathode via a cathode space, so that the following reaction will occur at the cathode side: O.sub.2+4H.sup.++4e.sup.−.fwdarw.2H.sub.2O (reduction/electron uptake).

[0047] In order to assure an ion conductivity for hydrogen protons through the PEM, the presence of water molecules in the PEM is necessary. Therefore, the cathode gas in particular is humidified before being supplied to the fuel cell, in order to bring about a moisture saturation of the PEM.

[0048] Since multiple fuel cells are placed together in the fuel cell stack, a sufficiently large quantity of cathode gas must be provided, so that a large mass flow of cathode gas is produced by a compressor, and due to the compressing of the cathode gas its temperature is greatly raised. The conditioning of the cathode gas, i.e., its adjustment in regard to the desired parameters in the fuel cell stack, is done in an intercooler as well as a humidifier 4.

[0049] The humidifier 4 represented as an embodiment in FIG. 6 has two end plates 5, between which are arranged a plurality of humidifier modules 6, the humidifier modules 6 being clamped between the end plates 5 by the tie rods 7. A different joining of the end plates 5, instead of the tie rods 7, is likewise conceivable by the use of bands, for example.

[0050] In the embodiment shown, for a more simplified drawing, the media ports 8 for the supply and the removal of the two media have been assigned to one of the end plates 5, while in the case of a fuel cell device the two media differ only in regard to their moisture content, but air is generally physically present. However, in general the possibility exists of arranging the media ports 8 for one of the media jointly on one of the end plates 5 or separately on both end plates 5 and arranging the media ports 8 for the other medium jointly on the same end plate or the other end plate as the media ports 8 for the first medium or separately on both end plates 5 with an inverted assignment of the media ports 8 for the supply and for the removal in regard to the first medium, i.e., the also humidifier modules 6 arranged in a row can experience a U or Z-shaped flow in regard to a medium, and when the two media are considered jointly a counterflow or a crossing counterflow is also possible.

[0051] FIG. 1 shows the layout of an individual humidifier module 6. On either side of the membrane 9 here there is arranged a flow field defined by spacers 11. The spacers 11 are formed by a yarn 13 stitched into the membrane 9, giving the membrane 9 a kind of skeletal structure. In FIG. 1, a plurality of parallel running rows of yarn 13 are stitched into the membrane 9, forming the spacers 11 defining the flow field.

[0052] Furthermore, a further yarn 22 is stitched into a margin region 23 of the membrane 9 at the circumference or applied onto the margin region 23. This enables a circumferential sealing of the humidifier module 6. In particular when the further yarn 22 is formed as an elastomer, this additional sealing action is achieved upon tightening or bracing the further yarn 22.

[0053] FIGS. 2 to 5 show various embodiments of the yarns 13 stitched into the membrane 9 or applied onto the membrane 9. In FIG. 3, the yarn 13 is led through the membrane 9 such that at least one yarn top piece 14 is arranged on a first side 16 and at least one yarn bottom piece 15 is arranged on a second side 17 of the membrane 9. The yarn top pieces 14 and the yarn bottom pieces 15 are consequently formed as a plurality of loops. Between the yarn top pieces 14 and the yarn bottom pieces 15 is arranged the flow field, so that the yarn top pieces 14 and the yarn bottom pieces 15 each form spacers 11.

[0054] FIG. 3 shows another embodiment, in which the flow field is additionally sealed off. For this, an additional yarn 18 is placed on the yarn top pieces 14 and the yarn bottom pieces 15 such that the additional yarn 18 lies at least for a section on the yarn 13, or on the yarn top pieces 14 or the yarn bottom pieces 15. At these nodal points 19 formed as bearing points, the additional yarn 18 can be fused to the yarn 13 by means of the action of heat if either the additional yarn 18 or the yarn 13 or both of them are formed from a thermoplastic material. The additional yarn 18 here may have a lower melting point than that of the yarn 13. At least the additional yarn 18 is formed here as a thermoplastic. The yarn 13, formed from a synthetic material, or from cotton or from hemp or from wool or the like, has a wicking action, so that liquid is taken up from the flow field by the yarn 13 and can be stored at least temporarily in it, the transport of the liquid from the wet side of the membrane 9 to the dry side of the membrane 9 being favored by the wick effect of the yarn 13. The yarn 13 with wick effect which is led through the membrane 9 thus forms a liquid bridge at each passage through the membrane 9.

[0055] FIG. 4 shows another embodiment, differing from the preceding one in that the additional yarn 18 is likewise stitched into the membrane 9 and this is led through the membrane 9 such that one or more of the yarn top pieces 14 and/or one or more of the yarn bottom pieces 15 are joined together at nodal points 19. These nodal points 19 or certain of the nodal points 19 may be fused together by means of the action of heat, in order to seal the flow field.

[0056] FIG. 5 shows another embodiment of the humidifier module 6, where the yarn 13 is formed as a top thread 20, while the additional yarn 18 is formed as a bottom thread 21. The top thread 20 and the bottom thread 21 are stitched into the membrane 9 like a lockstitch, so that a top thread loop of the top thread 20 is interwoven with the bottom thread 21 to form a nodal point 19. These nodal points 19 in turn can be fused together by means of the action of heat in order to achieve an additional sealing action.

[0057] The method for making the humidifier module 6 involves in particular the following steps: first, a membrane 9 is provided. A yarn 13 is stitched into the membrane 9 such that the yarn 13 forms at least two spacers 11 defining a flow field. Alternatively, the yarn 13 may be applied on the membrane 6 such that the yarn 13 forms at least two spacers 11 defining the flow field. The application can be done for example by means of 3-D printing methods.

[0058] The stitching of the yarn 13 into the membrane 9 or the application of the yarn 13 onto the membrane 9 is done in a plurality of parallel running rows. This makes it possible to create an especially large flow field. Furthermore, in order to achieve a sealing action, the yarn top pieces 14 and the yarn bottom pieces 15 can be fused to the additional yarn 18 at the nodal points 19. Alternatively, the nodal points 19 created by interweaving the top thread 20 with the bottom thread 21 can also be fused by means of the action of heat.

[0059] Alternatively or additionally, a further yarn 22 can be stitched into the margin region 23 of the membrane 9 at least for a section on the circumference. This enables an additional outer circumferential sealing of the humidifier module 6.

[0060] The method for making the humidifier 4 involves in particular the following steps: first, a plurality of humidifier modules 6 is provided. The humidifier modules 6 are fused together by means of the action of heat. In this way, the humidifier modules 6 are sealed against the outside. Furthermore, the plurality of fused-together humidifier modules 6 is arranged between the two end plates 5. By means of the tie rods 7, the humidifier modules are finally clamped with the end plates 5. It should be pointed out that a fusing of the nodal points 19 or the individual yarns 13, 18, 22 can also be produced by the mere clamping of the end plates 5. Thus, this corresponds to a cold forming of the yarns 13, 18, 22 or the nodal points 19 formed by them.

[0061] In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled.