DE202020106248U1 - Humidity exchangers, in particular humidifiers for a fuel cell, and fuel cell systems - Google Patents

Abstract

Humidity exchanger (1) for media flows, in particular humidifier (1) for a fuel cell (20),
- With a first supply line (3) for a first fluid to be dehumidified (FL1),
- With a second supply line (4) for a second fluid to be moistened (FL2),
- With a first discharge line (5) for the second fluid (FL2) which is humidified when it exits the moisture exchanger (1),
- With a second discharge line (6) for the first fluid (FL1), which is moisture-reduced when it exits the moisture exchanger (1), and
- With a stack (7) of moisture-permeable membranes (8) and distribution plates (9) arranged between the membranes (8) for guiding the fluids (FL1, FL2) to the membranes (8), the distribution plates (9) on their surface (9A, 9B) have flow channels (19) for the fluids (FL1, FL2) and are flow-connected to one another via collecting lines (15, 16, 17, 18); characterized in that the distribution plates (9) each have openings (12A, 12B, 12C, 12D) at opposite end regions (9D, 9E) of their planar extent and the openings (12A, 12B, 12C, 12D) of the stacked distribution plates (9 ) to form the collecting lines (15, 16, 17, 18) which extend essentially perpendicular to a surface plane of the distributor plates (9).

Description

The invention relates to a moisture exchanger, in particular a humidifier for a fuel cell, according to the type defined in more detail in the preamble of claim 1, and a fuel cell system with such a moisture exchanger.

Moisture exchangers for the transfer of moisture between two gases by means of moisture-permeable membranes are used in different areas such as B. fuel cell systems, in building technology for the recovery of moisture in room air conditioning or in medical technology application.

In a fuel cell, the energy of an electrochemical reaction of a fuel with an oxidizing agent is converted into electrical energy. In the mobile sector, for example in motor vehicles and ships, so-called polymer electrolyte fuel cells, or PEM fuel cells for short, are primarily used. It is named after a polymer membrane, mostly based on perfluorosulfonic acid functions (PFSA), which allows the chemical reaction of hydrogen and oxygen to form water to take place in a controlled manner. Low-temperature PEM fuel cells have a continuous operating temperature of approx. 60 ° C to 95 ° C. The membrane can be coated on both sides with a catalytic electrode. The oxygen is supplied from the ambient air and the hydrogen is carried along, for example, in a pressure tank in the motor vehicle.

To increase the dynamic efficiency, in practice an air inlet stream of the fuel cell is humidified, in particular with an air outlet stream of the fuel cell enriched with water vapor. A separate humidifier is used for this purpose in order to humidify the air inlet flow and / or the supplied hydrogen.

Such humidifiers are in different configurations, for example in the DE 103 93 213 T5 , the WO 2016/188 851 A1 , the DE 10 2014 201 248 A1 and the DE 10 2016 224 478 A1 described.

The invention is based on the object of creating a moisture exchanger, in particular a humidifier for a fuel cell, and a fuel cell system in which the efficiency is improved while at the same time having a simple structural design.

According to the invention, these objects are achieved by a moisture exchanger with the features of claim 1 and a fuel cell system according to claim 14.

• - Eine erste Zuleitung für ein erstes, zu entfeuchtendes Fluid,
• - eine zweite Zuleitung für ein zweites, zu befeuchtendes Fluid, welches bei Eintritt in den Feuchtetauscher einen geringeren Feuchtegehalt als das erste Fluid aufweist,
• - eine erste Ableitung für das bei Austritt aus dem Befeuchter angefeuchtete zweite Fluid,
• - eine zweite Ableitung für das bei Austritt aus dem Befeuchter feuchtereduzierte erste Fluid, und
• - einen Stapel aus feuchtigkeitsdurchlässigen Membranen, insbesondere Perfluorsulfonsäure-Flachmembranen, und zwischen den Membranen angeordneten Verteilerplatten zur Führung der Fluide an die Membranen, wobei die Verteilerplatten an ihrer Oberfläche Strömungskanäle für die Fluide aufweisen und über Sammelleitungen miteinander strömungsverbunden sind.

A moisture exchanger for media flows, in particular a humidifier for a fuel cell, is therefore proposed, which has:

• - A first supply line for a first fluid to be dehumidified,
• - A second feed line for a second fluid to be humidified which, when entering the moisture exchanger, has a lower moisture content than the first fluid,
• - a first derivation for the second fluid humidified when it exits the humidifier,
• a second discharge line for the first fluid, which is moisture-reduced when it exits the humidifier, and
• A stack of moisture-permeable membranes, in particular perfluorosulfonic acid flat membranes, and distributor plates arranged between the membranes for guiding the fluids to the membranes, the distributor plates having flow channels for the fluids on their surface and being flow-connected to one another via collecting lines.

According to the invention, the distributor plates have openings within an outer edge at opposite end regions of their planar extent, which are also referred to as manifolds, the openings of the stacked distributor plates overlapping to form the manifold extending essentially perpendicular to a surface plane of the distributor plates.

The core idea of the invention is that the moisture exchanger is equipped with distributor plates which, in an alternating arrangement with a membrane, separate the respective fluid flows, whereby by means of integrated manifolds supplying the flow field, a simple construction for an effective moisture exchange between the fluids flowing past each other in the moisture exchanger is provided by means of the membranes arranged in each case between the distributor plates.

An adaptation to the flow rate of the fluid to be humidified, to the required operating pressures and an existing installation space, for example in a motor vehicle, can be achieved by selecting the shape of the membranes and the associated distribution plates and the height of the stack, which is determined by the number of membranes and Distribution plates is intended to be made.

The openings, which enable a fluid flow through the stack, for example to allow the moist and the fluid to be moistened to pass from one membrane to the next, can each be in their shape, number and size in Depending on the amount of fluid passed through and the stack size can be selected. In particular, these openings can also be connected directly to fluid lines in the interior of the housing with the respective inlet and outlet lines for the various fluids on the housing in order to obtain a direct fluid flow through the stack.

The distributor plates can in principle have any geometric shape and, for example, have a rectangular, round, oval or angled surface.

In an advantageous embodiment, the distribution plates are designed to be essentially rectangular in their surface plane, with an opening being arranged in each corner area.

Such a breakthrough can in principle also have any geometry. In the case of a rectangular distributor plate, with regard to the flow guidance, it is advantageous if it has an at least approximately triangular contour which, on two sides, follows the outer contour of the distributor plate.

For a particularly efficient and compact structure of the stack of distributor plates and membranes, it is advantageous if open flow channels for one of the fluids are arranged on each surface side of the distributor plates.

In this way, the moisture exchanger can be operated in countercurrent. For example, the moist fluid flows in the longitudinal direction through a columnar manifold, and in the opposite direction the dry fluid flows through a columnar manifold in the stack. From this, a fluid to be humidified or dehumidified can be fed through the openings or manifolds on both sides of the distributor plate, so that on both sides of a membrane arranged between two distributor plates the respective fluids are forced past one another in countercurrent and an exchange of Water molecules takes place so that the dry fluid is moistened.

In principle, with an appropriate arrangement of the flow channels, operation in cross flow or cross flow or in direct flow can also be provided if this is sufficient for the required performance. With increased performance requirements, countercurrent operation is preferable because of its increased moisture transfer rate.

Perfluorosulfonic acid is proposed as the material for the membranes. From this, membranes can be designed in particular as flat membranes, which enable a good exchange of the water vapor from the moist to the dry fluid. However, the person skilled in the art can also choose a different type of membrane adapted to the application and performance requirements.

In an advantageous embodiment with an optimal supply of the active surface of the respective membrane, the respective fluid is guided on an upper or lower surface side of the distributor plates between diagonally opposite openings over a channel geometry of the flow channels that distributes the fluids evenly, whereby it is expedient for at least approximately rectangular distributor plates is to provide four openings each in the corner areas of the distributor plates.

The geometry of the flow channels on one surface side of the distributor plates can be designed in such a way that an inlet-side distributor area adjoins an opening or manifold to which the fluid to be carried on the respective surface side is supplied from the corresponding collecting line formed in the stack the fluid is distributed at least over a predominant width of the distribution plate. In other words, the fluid flowing out of the collecting line and the corresponding opening into the flow field on the respective surface side of the distributor plate is distributed in a targeted manner over the width of the distributor plate and thus also the adjacent membrane.

Analogously, an opening at which this fluid is discharged can be bordered by an outlet-side distributor area in which the fluid distributed over the width of the distributor plate is collected in the direction of this opening. The flow field can be designed as a planar funnel against this end area of the distributor plate.

Between the distributor areas, the respective fluid is preferably guided in a central flow channel section over a longitudinal extension of the distributor plate.

The inlet-side as well as the outlet-side distributor areas can be designed to be at least approximately triangular or trapezoidal and, starting from an edge between the openings placed, for example, in corners, widen towards the middle flow channel section. The flow channels formed in the respective distributor area can run diagonally to a longitudinal extension of the distributor plate and thus lead fluid from an opening in a corner over the entire width of the distributor plate or vice versa.

The flow channels in the middle flow channel section can, for. B. depending on the requirements of the adjacent membrane straight, meandering or wavy.

The distribution plates can be made of a metal, e.g. B. made of stainless steel, aluminum, titanium, etc., made of plastic or a composite material with plastic, such as. B. a metal-plastic composite.

To form the collecting lines, which supply the flow fields with fluid or discharge the fluid again, not only the distributor plates can have openings, but the membranes can also have recesses that overlap at least some of the openings in the distributor plates and thus allow an unimpeded flow of fluid vertically the manifold plates and membranes in the manifolds.

In a preferred embodiment, a sealing device is expediently arranged on the distributor plates in the region of the openings. For this purpose, z. B. a flat rubber seal between the distributor plate and the membrane, which is shaped such that it allows a flow of the respective fluid only in the associated flow channels or collecting lines.

Such a sealing device can not only be inserted between a distributor plate and an adjacent membrane, but can also be molded onto the distributor plate or the membrane in a simple manner.

In one embodiment of a moisture exchanger according to the invention, the stack of membranes and distribution plates arranged between the membranes can be delimited on each side by an end plate which has openings which overlap with the openings in the distribution plates and which also form the collecting lines.

The end plates and / or the distributor plates are preferably each gas-impermeable.

The stack of membranes and distributor plates is preferably surrounded by a housing. This housing is expediently designed to correspond to the shape of the stack and can therefore have any shape or cross-section, for example rectangular, round or oval.

A dry fluid, such as. B. in an application in conjunction with a fuel cell, hydrogen, pure oxygen or ambient air, as well as a moist or wet fluid introduced into the housing, and the humidified fluid and the moisture-reduced fluid are diverted from the housing via two discharge lines.

The moisture exchanger expediently has connections for connection to pumps or the like, in particular at the inlet and outlet lines, in order, for example, to blow the moist fluid into the housing at a desired overpressure so that it flows through the stack. Furthermore, the moistened fluid can be sucked out of the housing by means of negative pressure, for example.

The stack of membranes and distributor plates can be compressed or compressed to the desired extent by a tensioning device.

In an advantageous embodiment, such a tensioning device is arranged inside the housing. When the clamping device is arranged with associated clamping elements in the interior of the housing, a defined tension or compression is exerted on the stack. In particular, this is not changed by temperature-related expansion of the housing during operation. The manufacturing tolerances of the housing do not affect the clamping device either.

In principle, the tensioning device arranged in the interior of the housing for compressing the stack can be designed in any manner.

In an advantageous embodiment, the tensioning device can be formed by projections, cantilevered shoulders or the like in the interior of the housing, between which the stack of membranes and distributor plates is, so to speak, clamped.

Furthermore, it can be advantageous to compress the stack using tensioning straps.

In a further advantageous embodiment, the tensioning device can be formed by tension rods and end plates. If the stack of, for example, rectangular membranes and distributor plates is inserted between two end plates, the stack can then be tensioned or compressed to the desired extent with tension rods, which are arranged, for example, at the four corners of the stack and reach through the end plates.

To this end, the tie rods can each be equipped with threads. With these, as well as with nuts and tension springs, which are screwed towards the end plates, the stack is compressed. This allows one Fixed mechanical structure that practically does not change during operation of the humidity exchanger, so that constant contact pressure is guaranteed at all times.

The housing with the supply and discharge lines can preferably be made of metal
and / or plastic. The housing is preferably formed by two plastic half-shells which, for example, are designed as plastic injection-molded parts, each with the corresponding connection pieces for the supply and discharge lines, preferably in one piece.

Seals, for example made of silicone or an elastomer, can also be provided on the connection of the half-shells and / or on the supply and discharge lines, or the connecting pieces formed for this purpose on the housing. The housing is sufficiently dimensioned for the prevailing pressures of the fluids when the moisture exchanger is in operation.

Furthermore, the humidity exchanger is preferably equipped with pressure and / or temperature sensors in order to be able to monitor correct operation of the humidity exchanger.

The housing can also be designed in such a way that flow channels are formed laterally between the housing and the stack arranged therein.

In order to be able to set a desired degree of humidity of the humidified medium, a bypass with a valve for a fluid, in particular the humid fluid, can also be provided in the interior of the housing.

If the moist medium has too high a degree of moisture, for example, such a valve can be opened automatically at the corresponding supply line in the housing via a corresponding control with sensors in order to divert part of this medium past the actual stack via the bypass inside the housing. Only at the corresponding discharge line on the other side of the housing does this partial flow of the moist fluid mix again with the fluid that has flowed through the stack, the degree of moisture of which is correspondingly reduced. Thus, the total amount of water that is transferred to the dry fluid is reduced.

The bypass can be formed by a pipeline and / or by an intermediate space that is present between the actual stack and the housing.

In particular, if a delivery device for a medium, such as a pump or turbine, is present in an overall system comprising a moisture exchanger and a fuel cell, a water separator can be assigned to the moisture exchanger. With this water separator, for example, water can be withdrawn from the humidified medium with a possibly too high degree of humidity at the outlet of the humidity exchanger, where the humidified medium is drained from the housing. Such a water separator can be designed in a manner known per se.

It is also proposed that a heat exchanger be assigned to the moisture exchanger. With the heat exchanger, hot fluids can be cooled and / or cold fluids can be warmed up in order to ensure optimum operation. In principle, several heat exchangers can also be provided for the various fluids.

The moisture exchanger according to the invention can in principle be used in various technical areas, such. B. in the aforementioned areas of fuel cell systems, building technology, medical technology or food technology.

The moisture exchanger according to the invention develops particular advantages in a fuel cell system, in particular a motor vehicle, which has at least one fuel cell and at least one proposed moisture exchanger.

In such a fuel cell system, the first feed line of the moisture exchanger for the first fluid to be dehumidified can be connected to a cathode outlet of the at least one fuel cell and the first outlet line for the second fluid humidified upon exiting the moisture exchanger can be connected to a cathode inlet of the at least one fuel cell.

The water vapor-saturated exhaust air of the actual fuel cell is preferably fed to the moisture exchanger, which here serves as a humidifier for the fuel cell, as the moist fluid. This exhaust air is on the one hand heated by the reaction process taking place in the fuel cell and on the other hand is enriched with moisture or water vapor by the water produced during the reaction process.

The humidifier can be designed to humidify different fluids such as ambient air, which is supplied to the fuel cell as an oxygen source, or pure oxygen, which is taken from a pressure tank, for example.

The construction of the distribution plates with integrated openings or manifolds allows a direct connection of the moisture exchanger to the fuel cell without external piping.

Further advantages and advantageous embodiments of the invention emerge from the claims for protection and the exemplary embodiments described in principle below with reference to the drawing.

It goes without saying that the features mentioned above and still to be explained below can be used not only in the respectively specified combination, but also in other combinations.

• 1 eine schematische Darstellung eines Feuchtetauschers und einer Brennstoffzelle;
• 2 eine Darstellung des Feuchtetauschers in einer ersten Ausführungsform mit einem geöffneten Gehäuse;
• 3 eine Darstellung des Feuchtetauschers gemäß 2 mit geschlossenem Gehäuse;
• 4 eine schematisierte Draufsicht auf eine erste Oberflächenseite einer Verteilerplatte des Feuchtetauschers gemäß 1 bis 3;
• 5 eine schematisierte Draufsicht auf eine zweite Oberflächenseite einer Verteilerplatte gemäß 4;
• 6 eine schematisierte Draufsicht auf eine erste Oberflächenseite einer Verteilerplatte, welche eine alternative Strömungsfeldgeometrie gegenüber der Verteilerplatte der 4 und 5 aufweist;
• 7 eine schematisierte Draufsicht auf eine erste Oberflächenseite einer weiteren Verteilerplatte, welche eine alternative Strömungsfeldgeometrie gegenüber den Verteilerplatten der 4 bis 6 aufweist; und
• 8 einen bereichsweisen Querschnitt durch die Verteilerplatte der 4 und 5 entlang der Linie V-V in 5.

It shows:

• 1 a schematic representation of a moisture exchanger and a fuel cell;
• 2 a representation of the moisture exchanger in a first embodiment with an open housing;
• 3 a representation of the moisture exchanger according to 2 with closed housing;
• 4th a schematic plan view of a first surface side of a distributor plate of the moisture exchanger according to FIG 1 to 3 ;
• 5 a schematic plan view of a second surface side of a distributor plate according to FIG 4th ;
• 6th a schematic plan view of a first surface side of a distributor plate, which has an alternative flow field geometry compared to the distributor plate of FIG 4th and 5 having;
• 7th a schematic plan view of a first surface side of a further distributor plate, which has an alternative flow field geometry compared to the distributor plates of 4th to 6th having; and
• 8th a regional cross-section through the distributor plate of 4th and 5 along the line VV in 5 .

In the purely schematic and not to scale 1 to 8th the same components are denoted by the same reference numerals.

In 1 a fuel cell system of a motor vehicle (not shown in more detail) is shown in simplified form, the fuel cell system being a fuel cell 20th and a moisture exchanger 1 , which serves as a humidifier for the fuel cell, includes.

A first fluid FL1 and a second fluid FL2 , what a 1 are also identified by different hatching, flow through the moisture exchanger in the embodiment shown 1 in a countercurrent operation, with the fluids FL1 , FL2 by a pile only hinted at here 7th made of moisture-permeable membranes 8th with seal and distributor plates 9 inside a case 2 flow through.

The moisture exchanger 1 is with a fuel cell that is only indicated symbolically 20th , which is designed as a PEM fuel cell, connected from which the first fluid FL1 escapes as exhaust air that is moistened with water as a result of the chemical reaction in the fuel cell.

The second fluid FL2 , which has a lower moisture content than the first fluid FL1 has is, for example, ambient air that the fuel cell 20th is supplied and previously to increase the efficiency of the fuel cell 20th in the desired amount in the moisture exchanger 1 through the damp, from the fuel cell 20th discharged fluid FL1 is moistened.

The first fluid to be dehumidified F1 occurs in the direction of the arrow F1 through a first supply line 3 , which with a cathode output 21 the fuel cell 20th is connected to the moisture exchanger 1 and flows through it, while the second fluid to be moistened FL2 via a second supply line 4th inside the case 2 directed and in a flow direction according to the arrow F2 through the pile 7th flows. By flowing the first fluid F1 in countercurrent to the second fluid F2 the moisture content of this is reduced by some of its moisture being passed through the membranes 8th to the second fluid F2 emits, and flows from an associated derivative 6th back out of the case 2 in the direction of flow according to the arrow F3 out.

The second fluid FL2 that by flowing through the pile 7th in countercurrent to the first fluid F1 is increased in its humidity, flows in the direction of flow according to the arrow F4 back from the pile 7th or by an assigned derivative 5 , which with a cathode input 22nd the fuel cell 20th is connected, from the housing 2 out.

The cathode entrance 22nd and the cathode output 21 the fuel cell 20th are connected to a cathode subsystem of conventional design arranged therein.

The stack 7th comprises a plurality of distributor plates stacked on top of one another 9 , wherein between two immediately adjacent and one above the other arranged distribution plates 9 one each moisture permeable membrane 8th is arranged. The membranes 8th are designed here as perfluorosulfonic acid flat membranes.

For guiding the fluids FL1 , FL2 to the membranes 8th assign the distribution plates 9 present on both of their surfaces 9A , 9B Flow channels 19th for the fluids FL1 , FL2 on which about columnar manifolds 15th , 16 , 17th , 18th inside the stack 7th with the supply lines 3 , 4th and derivatives 5 , 6th for the fluids FL1 , FL2 are flow-connected.

For training the collecting lines 15th , 16 , 17th , 18th have the essentially rectangular distributor plates 9 each at opposite end areas 9D , 9E their longitudinal extent, ie adjacent to their narrow sides, a total of four breakthroughs also known as manifolds 12A , 12B , 12C , 12D on. The distribution plates here have an identical geometry, so that the openings 12A , 12B , 12C , 12D of the stacked distribution plates 9 overlap and perpendicular to a surface plane of the distributor plates 9 the columnar manifolds 15th , 16 , 17th , 18th form.

The flat membranes 8th are in the embodiment shown for the formation of the collecting lines 15th , 16 , 17th , 18th also with recesses 8A formed showing the geometry of the breakthroughs 12A , 12D ; 12B , 12C the distribution plates 9 have and overlap with these.

The four in the respective distribution plate 9 integrated breakthroughs or manifolds 12A , 12B , 12C , 12D lie within an outer margin 9C the distribution plates 9 present in each case in a corner area 9F , 9G , 9H , 9Y the distribution plate 9 and have a triangular contour, so that two side edges of the openings 12A , 12B , 12C , 12D parallel to the outer edge 9C the distribution plate 9 run away. Instead of the triangular contour, a round, square, slot-like or other shape suitable for flow technology would of course also be conceivable.

The flow channels 19th to guide the flow over the membranes 8th are in the 4th to 7th only indicated symbolically with a few lines, which do not reflect their number and specific shape. Such a formation is partially shown in 8th can be seen in more detail.

The 4th to 7th illustrate the flow paths of the fluids FL1 , FL2 which on each surface side 9A , 9B the distribution plates 9 in to the adjacent membrane 8th open flow channels 19th between the associated breakthroughs 12A , 12B , 12C , 12D and manifolds 15th , 16 , 17th , 18th are guided in countercurrent.

The fluids FL1 , FL2 point to the formation of a counterflow on both sides of a membrane 8th on the surfaces 9A , 9B two distribution plates arranged one above the other 9 the same flow direction as from a comparison of the 4th and 5 becomes apparent.

The 4th shows the basic flow path of the second, to be humidified and the fuel cell 20th fluids to be supplied FL2 , which dry supply air from a fresh air flow in the first manifold 15th is on a first "dry" page 9A the distribution plate 9 .

The dry fluid FL2 emerges from the manifold 15th through the associated first breakthrough 12A into the flow field of the distributor plate 12, in which it over the entire surface 9A the distributor plate to the diagonally opposite opening 12D with the outgoing manifold 18th to be led. When the fluids flow past each other FL1 , FL2 through the membranes 8th of the stack 7th there is an exchange of water molecules, so that the fluid is dry FL2 is moistened. The moistened fluid FL2 is based on the discharging manifold 18th and an external piping of the fuel cell connected thereto 20th fed.

The flow field for the moist first fluid is analogous FL1 on the other surface side 9B the distribution plate 9 , which in particular in 5 can be seen, constructed.

From a collecting line 17th , in which the moist exhaust air FL1 the fuel cell 20th is collected is through the associated breakthrough 12C the wet fluid FL2 on the distribution areas of the distribution plate 9 distributed and to the diagonally opposite breakthrough 16 out of which a manifold 16 , which serves as an exhaust pipe, the stale air FL1 with residual moisture.

The geometric arrangement of the flow channels 19th on the respective surface side 9A , 9B is designed in such a way that there is a breakthrough 12A , 12D ; 12B , 12C on which that on the respective surface side 9A , 9B fluid to be conducted FL1 or. FL2 is supplied, an inlet-side distributor area 19A borders in which the fluid FL1 or. FL2 across the width of the distributor plate 9 is distributed.

Opposite in the area of the opening where the fluid in question FL1 or. FL2 is discharged is a distribution area on the outlet side 19C provided in which the across the width of the distributor plate 9 distributed fluid in the direction of this effluent breakthrough 12A , 12D ; 12B , 12C is collected.

Between the distribution areas 19A , 19C is a central flow channel section 19B in which the fluid in question FL1 , FL2 over a longitudinal extension of the distributor plate 9 to be led.

The distribution areas 19A , 19C are approximately triangular or trapezoidal between the openings 12A , 12D ; 12B , 12C an end area 9D , 9E the distribution plate 9 with diagonal to a longitudinal extension of the distributor plate 9 running flow channels 19th educated.

The construction of the distribution plates 9 with the breakthroughs or manifolds 12A , 12D ; 12B , 12C allows a Z and a U flow.

The active surface with the flow channels 19th can basically be provided with all gradient geometries. For example, the flow channels 19th in the middle flow channel section 19B the 4th and 5 just trained while in the in 6th obvious alternative angularly meandering and in the in 7th apparent alternative are designed to be wavy.

Likewise, the cross section of the individual channel geometry of the flow channels 19th can be represented in any geometric shape. In the 8th an example with a trapezoidal cross-section can be seen, the flow channels having a distance a of 1 mm, a height b of 0.5 mm and a radius transition R of 0.1 mm. However, a rectangular, square, semicircular, triangular or elliptical shape is also conceivable.

On the distributor plates 9 , which in the present case are made of plastic, is at least in the area of the openings 12A , 12D ; 12B , 12C one in 1 only symbolically indicated sealing device 23 arranged. This represents a flat rubber seal, which is shaped in such a way that it allows a flow of the respective fluid FL1 , FL2 only in the assigned flow channels 19th or manifolds 15th , 16 , 17th , 18th allows.

The flat rubber seal 23 is present directly on the distributor plates 9 molded on, but this can also represent a separately inserted component. The sealing device can also extend over the entire distributor plate and in particular along the outer edge 9C the distribution plates 9 extend.

The case 2 of the moisture exchanger 1 which is in 2 open and in 3 is shown closed, can be made of metal and / or plastic, the housing shown 2 made of plastic with two half-shells 2A , 2 B is made. In the case of an embodiment made of plastic, the nozzle-like supply and discharge lines 3 , 4th , 5 , 6th manufactured as a plastic injection molded part and preferably in one piece with the housing 2 or a half-shell 2A , 2 B be trained.

The two half-shells 2A , 2 B of the housing 2 are here with screws 13th can be screwed together, it being possible for an additional fluid seal, for example made of silicone, to be provided.

To the pile 7th made of membranes 8th and distribution plates 9 To compress or clamp together to the desired extent is a clamping device 11 with two end plates 11A , 11B , for example made of metal, and several of the end plates 11A , 11B connecting tie rods 10 , which by means of clamping nuts 14th are intended.

Will the clamping nuts 14th and associated tension springs on a thread of the tension rod 10 on one end plate 11A or. 11B resting in the direction of the opposite end plate 11 B or 11A screwed down, then the stack 7th pressed together in the desired manner.

About the passage of the fluids FL1 , FL2 through the pile 7th to allow can in the end plates 11A , 11B also openings 12, as in the distributor plates 9 be trained.

The clamping device is here inside the housing 2 arranged. On the one hand, this has the advantage that the stack can have any shape or size 7th can be realized, regardless of the shape and size of the housing 2 , and on the other hand occurs through the immediate tensioning of the stack 7th in the housing 2 practically no deformation of the stack due to the clamping device during operation, in particular with changing temperatures 7th so that there is a constant result even in continuous operation.

In particular, there remains a slight deformation of the housing 2 without affecting the tension of the stack 7th . The housing can also be 2 just open and close, and a stack 7th can be exchanged quickly.

It goes without saying that the moisture exchanger 1 as well as the fuel cell 20th can be equipped with appropriate sensors for pressure, temperature and humidity of the individual fluids and that pumps and / or suction devices, water separators, heat exchangers and the like can be assigned to the entire system, in particular to the humidity exchanger 1 to be able to operate with the desired parameters via a corresponding control.

For example, such a mass throughput of the fluids FL1 , FL2 as well as their moisture content when it exits the humidifier 1 can be set.

List of reference symbols

1

Humidifier

2

casing

2A

Half shell

2 B

Half shell

3

first lead

4th

second supply line

5

first derivative

6th

second derivative

7th

stack

8th

membrane

8A

Recess

9

Distribution plate

9A

Distribution plate surface

9B

Distribution plate surface

9C

outer edge distribution plate

9D

Distribution plate end area

9E

Distribution plate end area

9F

Corner area distributor plate

9G

Corner area distributor plate

9H

Corner area distributor plate

9Y

Corner area distributor plate

10

Tie rod

11

Clamping device

11A

End plate

11B

End plate

12A

breakthrough

12B

breakthrough

12C

breakthrough

12D

breakthrough

13th

screw

14th

Tension nut with tension spring

15th

Manifold

16

Manifold

17th

Manifold

18th

Manifold

19th

Flow channels

19A

inlet-side distribution area

19B

middle flow channel section

19C

distribution area on the outlet side

20th

Fuel cell

21

Cathode output

22nd

Cathode entrance

23

Sealing device, flat rubber seal

F1

Direction of flow

F2

Direction of flow

F3

Direction of flow

F4

Direction of flow

FL1

first fluid to be dehumidified

FL2

second fluid to be moistened

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 10393213 T5 [0005]
• WO 2016/188851 A1 [0005]
• DE 102014201248 A1 [0005]
• DE 102016224478 A1 [0005]

Claims (15)

Humidity exchanger (1) for media flows, in particular humidifier (1) for a fuel cell (20), - with a first supply line (3) for a first fluid (FL1) to be dehumidified, - with a second supply line (4) for a second, Fluid to be humidified (FL2), - with a first discharge line (5) for the second fluid (FL2) that is humidified when it exits the humidity exchanger (1), - with a second discharge line (6) for the fluid when it exits the humidity exchanger (1) moisture-reduced first fluid (FL1), and - with a stack (7) of moisture-permeable membranes (8) and distribution plates (9) arranged between the membranes (8) for guiding the fluids (FL1, FL2) to the membranes (8), wherein the distributor plates (9) have flow channels (19) for the fluids (FL1, FL2) on their surface (9A, 9B) and are flow-connected to one another via collecting lines (15, 16, 17, 18); characterized in that the distribution plates (9) each have openings (12A, 12B, 12C, 12D) at opposite end regions (9D, 9E) of their planar extent and the openings (12A, 12B, 12C, 12D) of the stacked distribution plates (9 ) to form the collecting lines (15, 16, 17, 18) which extend essentially perpendicular to a surface plane of the distributor plates (9). Moisture exchanger after Claim 1 , characterized in that the distribution plates (9) are essentially rectangular in their surface plane, an opening (12A, 12B, 12C, 12D) being arranged in each corner area (9F, 9G, 9H, 9J). Moisture exchanger after Claim 1 or 2 , characterized in that open flow channels (19) for one of the fluids (FL1, FL2) are arranged on each surface side (9A, 9B) of the distributor plates (9), the respective fluids (FL1, FL2) therein between the associated openings (12A, 12B, 12C, 12D) and collecting lines (15, 16, 17, 18) are preferably guided in countercurrent. Moisture exchanger after one of the Claims 1 to 3 , characterized in that the fluids (FL1, FL2) on the surfaces (9A, 9B) of two distribution plates (9) arranged one above the other have the same flow direction, so that on both sides of a membrane (8) there is a counterflow between the first fluid to be dehumidified ( FL1) and the second fluid to be humidified (FL2) takes place. Moisture exchanger after one of the Claims 1 to 4th , characterized in that the respective fluid (FL1, FL2) is guided on a surface side (9A, 9B) of the distributor plates (9) between diagonally opposite openings (12A, 12D; 12B, 12C). Moisture exchanger after one of the Claims 1 to 5 , characterized in that the geometry of the flow channels (19) on one surface side (9A, 9B) is designed in such a way that an opening (12A, 12D; 12B, 12C) on which the on the respective surface side (9A, 9B) fluid (FL1, FL2) to be guided is supplied, an inlet-side distributor area (19A) borders in which the fluid (FL1, FL2) is distributed at least over a predominant width of the distributor plate (9), that at an opening (12A, 12D; 12B, 12C), at which this fluid (FL1, FL2) is discharged, borders an outlet-side distributor area (19C) in which the fluid (FL1, FL2) distributed over the width of the distributor plate (9) in the direction of this opening (12A, 12D; 12B, 12C) flows, and that between the distributor regions (19A, 19C) there is a central flow channel section (19B) in which the fluid (FL1, FL2) is guided over a longitudinal extension of the distributor plate (9). Moisture exchanger after Claim 6 , characterized in that the distribution areas (19A, 19C) in particular at least approximately triangular or trapezoidal between the openings (12A, 12D; 12B, 12C) of an end area (9D, 9E) of the distribution plate (9) with diagonal to a longitudinal extension of the distribution plate ( 9) extending flow channels (19) are formed. Moisture exchanger after Claim 6 or 7th , characterized in that the flow channels (19) in the central flow channel section (19B) run straight, meandering or undulating. Moisture exchanger after one of the Claims 1 to 8th , characterized in that the distributor plates (9) are formed from a plastic or a composite material with plastic. Moisture exchanger after one of the Claims 1 to 9 , characterized in that the membranes (8) for forming the collecting lines (15, 16, 17, 18) have recesses (8A) which overlap at least some of the openings (12A, 12D; 12B, 12C) of the distributor plates (9) . Moisture exchanger after one of the Claims 1 to 10 , characterized in that a sealing device (23), in particular a flat rubber seal, is arranged on the distributor plates (9) at least in the area of the openings (12A, 12D; 12B, 12C), which is shaped such that it allows a flow of the respective fluid (FL1, FL2) only in the assigned flow channels (19) or collecting lines (15, 16, 17, 18). Moisture exchanger after one of the Claims 1 to 11 , characterized in that the stack of membranes (8) and distribution plates (9) arranged between the membranes (8) is delimited on each side by an end plate (11A, 11B), which preferably has the openings (12A, 12D; 12B, 12C) of the distributor plates (9) have openings which overlap the collecting lines (15, 16, 17, 18). Moisture exchanger after Claim 12 , characterized in that the stack of membranes (8) and distribution plates (9) arranged between the membranes (8) is surrounded by a housing (2) and is compressed by means of a tensioning device (11) arranged inside the housing (2), wherein the tensioning device (11) is preferably formed by the end plates (11A, 11B) and tie rods (10) connecting them. Fuel cell system, in particular of a motor vehicle, comprising at least one fuel cell (20) and a moisture exchanger (1) according to at least one of the Claims 1 to 13th . Fuel cell system according to Claim 14 , characterized in that the first supply line (3) of the moisture exchanger (1) for the first fluid (FL1) to be dehumidified with a cathode outlet (21) of the at least one fuel cell (20) and the first discharge line (5) for the outlet from the moisture exchanger (1) humidified second fluid (FL2) is connected to a cathode inlet (22) of the at least one fuel cell (20).

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