DE102019211583A1 - Process for manufacturing a humidifier and humidifier - Google Patents

Abstract

The invention relates to a method for manufacturing a humidifier (2) in which a first humidifier module (12) is printed in a generative manufacturing step, a membrane (11) is placed on the surface of the first humidifier module (12) and in a further generative manufacturing step a second humidifier module (14) is further printed on the first humidifier module (12) and the membrane (11). The invention also relates to a humidifier (2).

Description

The invention relates to a method for producing a humidifier, in which a first humidifier module is printed in a generative manufacturing step, a membrane is placed on the surface of the first humidifier module and in a further generative manufacturing step a second humidifier module is further printed on the first humidifier module and the membrane . The invention also relates to a humidifier.

Humidifiers are generally used in order to be able to effect a transfer of the moisture to the drier medium in the case of two gaseous media with different moisture contents. Such gas / gas humidifiers are used in particular in fuel cell devices in which air is compressed with the oxygen contained therein in the cathode circuit to supply the cathode spaces of the fuel cell stack, so that relatively warm and dry compressed air is present, the moisture of which is suitable for use in the fuel cell stacks the membrane electrode assembly is insufficient. The dry air provided by the compressor for the fuel cell stack is humidified by being guided past a membrane that is permeable to water vapor, the other side of which is coated with the humid exhaust air from the fuel cell stack. For conditioning the air to be supplied to the cathode spaces of the fuel cell stack, its temperature control is also required, for which purpose charge air coolers positioned after the compressor are usually used. The humidifier and the charge air cooler are large components that contribute to a great increase in the required installation space for a fuel cell device and limit the efficiency of the fuel cell device because there are high thermal losses.

It should also be noted that humidifiers known from the previous state of the art are complex to assemble, since they have a modular structure and the individually manufactured modules must be sealed and braced against each other, so that the material expenditure for the seals and the clamping system is high and inaccuracies can lead to an uneven distribution of the fluids in the humidifier during assembly.

The DE 10 2016 224 478 A1 shows a membrane humidifier for a fuel cell system, which comprises a plurality of flow plates, between each of which a moisture-permeable membrane is arranged. The flow plates each have flow channels through which gases can be brought to the moisture-permeable membrane, a circumferential seal being arranged on a circumferential edge of the flow plate.

The US 2016/0093898 A1 shows a generatively manufactured bipolar plate for a fuel cell, which after its generative manufacture is polished and provided with a surface coating. This bipolar plate can be installed in a fuel cell after its final production.

The DE 10 2014 009 329 A1 describes a humidifying device which has a stacking unit with a plurality of membranes which are permeable to water vapor and which are arranged one above the other and spaced apart from one another. Two directly adjacent membranes are connected in a flow-tight manner at a first edge area and are arranged in a second edge area arranged at an angle between sealing strips lying one above the other, between which flow openings are formed.

The object of the present invention is therefore to specify a method with which the manufacture of a humidifier can be simplified and to provide an improved humidifier.

This object is achieved by a method with the features of claim 1 and by a humidifier with the features of claim 7. Advantageous configurations with expedient developments of the invention are specified in the dependent claims.

The method according to the invention uses a generative manufacturing step to print a first humidifier module by means of a 3D printer, after which the 3D printer can pause to place the membrane on the printed first humidifier module in order to then switch to the 3D printer again to manufacture the second humidifier module. This type of production means that all seals that are required in previously known humidifiers can be dispensed with. In addition, the first humidifier module and the second humidifier module are already connected to one another, so that no further assembly is required either, and the otherwise required clamping system can be omitted.

It is advantageous if a receptacle is formed on the surface of the first humidifier module and the membrane is inserted into this receptacle, the receptacle being used to compensate for the membrane thickness. Alternatively, it is also possible to place the membrane on the flat surface of the first humidifier module and to form the receptacle in the second humidifier module, the first-mentioned alternative with regard to the precise positioning of the membrane is preferred.

The performance of the humidifier can be easily scaled by using multiple membranes with associated humidification modules, the method according to the invention offering the possibility of the method steps being repeated iteratively up to the specified size of the humidifier with the desired number of humidifier modules. Here, too, it should be pointed out that subsequent assembly is not required and that there is no need for seals or a clamping system.

The first humidifier module and / or the second humidifier module is expediently designed as a flow field frame with an assigned flow field in which flow channels are separated from one another by webs. The webs are used to support the membrane and are used to guide the flowing fluids, whereby, due to the nature of the manufacturing process used, a wide variety of shapes and courses of the webs and thus the flow channels or the supply lines and drains can be realized without any problems. So there are bulges in which a liquid can collect, or for example constrictions to modify the flow rate.

It is also advantageous that in an additive manufacturing step the hose connections are formed on at least one end plate or at the edge on at least one side plate, i.e. the humidifier is created as a whole as a unit in the additive manufacturing process on a 3D printer, with a temperature-resistant plastic is used. PEEK is only mentioned as an example of such a temperature-resistant plastic.

The humidifier created in this way with a plurality of membranes arranged between two humidifier modules is free of seals and free of a clamping system, whereby the design can also be freely selected within wide limits, i.e. better adaptation to the installation conditions is given if this humidifier is, for example, as Part of a fuel cell device is used in a motor vehicle.

Provision is made here for the membrane to have a perforation, which can be used for simple placement of the membrane on the surface of the first humidifier module if the first humidifier modules manufactured in the generative manufacturing step are assigned their receptacles for the membrane for interaction with the perforation of the membrane Have pins and / or the second humidifier modules in the generative manufacturing step have pegs printed through the perforation. This also secures the position of the membrane.

It should also be noted that the humidifier modules are designed as flow field frames with assigned flow fields, in which flow channels are separated by webs and the contour and / or the course of the flow channels, the feed lines that separate these webs and / or feed the flow channels due to their location and function is determined in that a narrowing of the contour is used to influence the flow velocity and a bend in the flow velocity is used to influence the separation and / or storage of water.

The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination, but also in other combinations or on their own, without the scope of the Invention to leave. There are thus also embodiments to be regarded as encompassed and disclosed by the invention, which are not explicitly shown or explained in the figures, but emerge from the explained embodiments and can be generated by separate combinations of features.

• 1 eine schematische Darstellung einer Brennstoffzellenvorrichtung mit einem darin genutzten Befeuchter,
• 2 eine schematische Schnittdarstellung durch einen aus mehreren Membranen mit zugeordneten Befeuchtermodulen gebildeten Befeuchter,
• 3 ein schematische Schnittdarstellung eines generativ gefertigten Befeuchtermodul mit oberhalb der Aufnahme positionierter Membran,
• 3A das erste Befeuchtermodul mit zugeordneter Membran nach dem Verfahrensschritte des Platzierens der Membran in der Aufnahme in einer der 3 entsprechende Darstellung,
• 4 eine der 2 entsprechende Darstellung mit perforierten Membranen,
• 5 eine der 3 entsprechende Darstellung mit der Positionierung der perforierten Membran auf Stifte in der Aufnahme des ersten Befeuchtermoduls,
• 5A eine der 3 entsprechende Darstellung der Ausführungsform gemäß 5,
• 6 eine Draufsicht auf die Endplatte eines Befeuchters, die die Schlauchanschlüsse für den Einlass des trockenen Frischgases und den Einlass des feuchten Abgases und den Auslass für das feuchte Abgas und den Auslass für das befeuchtete Frischgas trägt,
• 7 eine der 6 entsprechende Darstellung mit seitlichen Schlauchanschlüssen,
• 8 eine transparente Darstellung des ersten Befeuchtermoduls, der Membran und des zweiten Befeuchtermoduls zur Veranschaulichung der Lage und Kontur der Membran, des Verlaufes der Strömungskanäle für das Frischgas und das Abgas und der Header für die Zu- und Ableitung des Frischgases und des Abgases,
• 9 eine 2 entsprechende Darstellung zur Erläuterung der Lage der Strömungskanäle, und
• 10 eine isolierte Darstellung eines Befeuchtermoduls mit gedruckten Tunnel für die Strömungsverbindung der Strömungskanäle mit den Headern.

Further advantages, features and details of the invention emerge from the claims, the following description of preferred embodiments and on the basis of the drawings. Show:

• 1 a schematic representation of a fuel cell device with a humidifier used therein,
• 2 a schematic sectional view through a humidifier formed from several membranes with assigned humidifier modules,
• 3 a schematic sectional view of a generatively manufactured humidifier module with a membrane positioned above the receptacle,
• 3A the first humidifier module with an associated membrane after the method steps of placing the membrane in the receptacle in one of the 3 corresponding representation,
• 4th one of the 2 corresponding representation with perforated membranes,
• 5 one of the 3 corresponding representation with the positioning of the perforated membrane on pins in the receptacle of the first humidifier module,
• 5A one of the 3 corresponding representation of the embodiment according to 5 ,
• 6 a plan view of the end plate of a humidifier, which carries the hose connections for the inlet of the dry fresh gas and the inlet of the moist exhaust gas and the outlet for the moist exhaust gas and the outlet for the humidified fresh gas,
• 7th one of the 6 corresponding illustration with lateral hose connections,
• 8th a transparent representation of the first humidifier module, the membrane and the second humidifier module to illustrate the position and contour of the membrane, the course of the flow channels for the fresh gas and the exhaust gas and the headers for the supply and discharge of the fresh gas and the exhaust gas,
• 9 a 2 corresponding illustration to explain the position of the flow channels, and
• 10 an isolated representation of a humidifier module with printed tunnels for the flow connection of the flow channels with the headers.

In the 1 Fig. 3 is a schematic of a fuel cell device 1 shown, this being a humidifier 2 for regulating the humidity of a plurality of in a fuel cell stack 3 combined fuel cells 4th includes.

Each of the fuel cells 4th comprises an anode, a cathode and a proton-conductive membrane separating the anode from the cathode. The membrane is formed from an ionomer, preferably a sulfonated polytetrafluoroethylene polymer (PTFE) or a polymer of perfluorinated sulfonic acid (PFSA). Alternatively, the membrane can also be formed as a sulfonated hydrocarbon membrane.

A catalyst can also be added to the anodes and / or the cathodes, the membranes preferably being coated on their first side and / or on their second side with a catalyst layer made of a noble metal or a mixture comprising noble metals such as platinum, palladium, ruthenium or the like , which serve as a reaction accelerator in the reaction of the respective fuel cell.

The anode can be supplied with fuel (for example hydrogen) via an anode compartment. In a polymer electrolyte membrane fuel cell (PEM fuel cell), fuel or fuel molecules 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 takes place at the anode: 2H ₂ → 4H ⁺ + 4e ^- (oxidation / electron release). While the protons pass through the PEM to the cathode, the electrons are conducted to the cathode or to an energy store via an external circuit.

The cathode gas (for example oxygen or air containing oxygen) can be fed to the cathode via a cathode compartment, so that the following reaction takes place on the cathode side: O ₂ + 4H ⁺ + 4e ^- → 2H ₂ O (reduction / electron uptake).

Because in the fuel cell stack 3 several fuel cells 2 are summarized, a sufficiently large amount of cathode gas must be made available so that through a compressor 5 a large cathode gas mass flow or fresh gas flow is provided, the temperature of which increases significantly as a result of the compression of the cathode gas. The conditioning of the cathode gas or the fresh air gas flow, i.e. its setting with regard to that in the fuel cell stack 3 desired temperature and humidity, takes place in a charge air cooler, not shown in detail, downstream of the compressor, and in the humidifier 2 , the moisture saturation of the membranes of the fuel cells 4th to increase their efficiency, as this favors the transport of protons.

The fuel cell stack is on the anode side 3 fluid-mechanically connected to an anode supply line, so that in the fuel reservoir shown schematically 6 contained fuel the fuel cell stack 3 can be fed. A valve or a suction jet pump can be suitable for realizing the desired partial pressure of fresh fuel within the anode circuit, which comes about through the anode recirculation line. With such an anode recirculation line, the in the fuel cell stack 3 unused fuel the anode compartments upstream of the fuel cell stack 3 are fed again, so that the anode recirculation line opens again into the anode feed line. In order to discharge the liquid from the anode circuit, a separator is integrated in the anode recirculation line. This is fluid mechanically with the cathode side of the fuel cell device 1 connected, so that the liquid occurring on the anode side, for example, in the downstream of the fuel cell stack 3 existing cathode exhaust line 8th is introduced to the liquid for example from the fuel cell device 1 to divert. As an alternative or in addition, the liquid that occurs on the anode side can be taken from the separator 7th also in one Cathode feed line 9 upstream of the humidifier 2 open, so that the liquid is entered there into the fresh cathode gas before it enters the humidifier 2 got. This has the advantage that the humidifier 2 can be designed to be smaller overall, since the fresh, due to the compression by means of the compressor 5 dry fresh gas can then no longer be humidified as much as it can in the fuel cell stack 3 to ensure the required humidity of the membranes.

To the mass flow of the cathode gas through the fuel cell stack 3 Being able to regulate is a bypass 10 present, which has an actuator, in particular a pressure control valve. This bypass 10 connects the cathode supply line 9 with the cathode exhaust line 8th .

The one in the fuel cell device 1 used humidifiers 2 , is a large and expensive component that requires a large amount of space, which is particularly disadvantageous when the fuel cell device 1 to be operated in a motor vehicle. An improved humidifier 2 each with a membrane arranged between two humidifier modules 11 is characterized in that it is designed free of seals and free of a tensioning system, this being made possible by the use of an additive manufacturing method in which a first humidifier module is used in a first additive manufacturing step 12 is printed. In the embodiment shown in the drawing, this first humidifier module 12 a recording 13 on the surface. After manufacturing the first humidifier module 12 the 3D printer used for the additive manufacturing process is stopped and the membrane 11 inserted into the receptacle, the depth of which is dimensioned such that the membrane thickness is compensated and a flat surface is again provided on which a second humidifier module is provided in a further generative manufacturing step 14th is printed ( 3 and 3A) . These procedural steps can be repeated iteratively until the humidifier 2 has reached the specified size, so that in principle a monolithic block can be used as a humidifier 2 results like this in the 2 is shown with the between the humidifier modules 12 , 14th positioned membranes 11 . From the 2 can also be seen that the hose connections 15th are included in the additive manufacturing process, whereby the 2 shows that the hose connections 15th are formed terminally, namely on two end plates. It is only mentioned as an example that the lower left hose connection 16 can be used for the dry fresh gas, while the lower right hose connection 17th is used for the moist exhaust gas. At the top left is the outlet for the humid exhaust gas, while at the top right is the outlet 19th for the humidified fresh gas. In the embodiment 2 is a counterflow for the humidifier modules assigned to a membrane 12 , 14th shown, while a direct, cross or cross countercurrent flow can also be implemented.

The 6 shows an example in which all hose connections 15th are assigned to an end plate, while the 7th refers to the fact that, due to the generative manufacturing process, the hose connections are also designed in a simple manner 15th on the side of the humidifier 2 is possible to feed from the 8th to 10 visible header 20th .

The 4th to 5 point out that also a membrane 11 with a perforation 21st can be used, for interacting with the perforation 21st the first humidifier module manufactured in the generative manufacturing step 12 have their receptacles for the membrane associated pins or the second humidifier modules 14th in the generative manufacturing step through the perforation 21st use printed cones.

The 8th and 10 let the design of the humidifier modules 12 , 14th recognize that as a flow field frame 23 with assigned flow fields are formed in which flow channels 25th through bars 24 are separated. It should also be pointed out that the course and contour of the flow channels are due to the selected additive manufacturing process 25th or that of the supply of the flow channels 25th serving headers 20th can be adjusted to improve the flow behavior and to ensure better uniform distribution in the individual layers. Constrictions in the contour and bends in the flow channels can be used for such a modification 25th or baffles to deflect the flow.

List of reference symbols

1.

Fuel cell device

2.

Humidifier

3.

Fuel cell stack

4th

Fuel cell

5.

compressor

6th

fuel

7th

Separator

8th.

Cathode exhaust line

9.

Cathode feed line

10.

bypass

11.

membrane

12.

first humidifier module

13.

admission

14th

second humidification module

15th

Hose connections

16.

Hose connection fresh gas inlet

17th

Hose connection exhaust gas inlet

18th

Hose connection exhaust gas outlet

19th

Hose connection fresh gas outlet

20th

Header

21st

Perforation

22nd

pencils

23.

Flow field frame

24.

Bridges

25th

Flow channel

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 102016224478 A1 [0004]
• US 2016/0093898 A1 [0005]
• DE 102014009329 A1 [0006]

Claims (10)

Method for producing a humidifier (2), in which a first humidifier module (12) is printed in a generative manufacturing step, a membrane (11) is placed on the surface of the first humidifier module (12) and in a further generative manufacturing step on the first humidifier module (12) and the membrane (11) a second humidifier module (14) is further printed. Procedure according to Claim 1 , characterized in that a receptacle (13) is formed on the surface of the first humidifier module (12) and the membrane (11) is inserted into this receptacle (13). Procedure according to Claim 1 or 2 , characterized in that the method steps are repeated iteratively up to the predetermined size of the humidifier (2) with the desired number of humidifier modules (12, 14). Method according to one of the Claims 1 to 3 , characterized in that the first humidifier module (12) and / or the second humidifier module (14) is designed as a flow field frame (23) with an assigned flow field in which flow channels (25) are separated from one another by webs (24). Method according to one of the Claims 1 to 4th , characterized in that in a generative manufacturing step the hose connections (15) are formed on at least one end plate or at the edge on at least one side plate. Method according to one of the Claims 1 to 5 , characterized in that a temperature-resistant plastic is used. Humidifier with a plurality of membranes (11) each arranged between two humidifier modules (12, 14), characterized in that the design is free of seals and free of a tensioning system. Humidifier Claim 7 , characterized in that the membrane (11) has a perforation (21). Humidifier Claim 8 , characterized in that for the interaction with the perforation (21) of the membrane (11) the first humidifier modules (12) manufactured in the generative manufacturing step have pins (22) assigned to their receptacles (13) for the membrane (11) and / or the second humidifier modules (14) have pegs printed through the perforation (11) in the generative manufacturing step. Humidifier according to one of the Claims 7 to 9 , characterized in that the humidifier modules (12, 14) are designed as flow field frames (23) with assigned flow fields, in which flow channels (25) are separated by webs (24) and the contour and / or the course of the flow channels (25), the feed lines feeding these separating webs (24) and / or the flow channels (25) are determined based on their position and function by using a narrowing of the contour to influence the flow rate and a bend to influence the separation and / or storage of water.

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