DE102017211755A1 - Plug-in element for a header of a fuel cell stack - Google Patents

Abstract

The present invention relates to a male element for at least one header of a fuel cell stack for influencing and optimizing an inflow within the fuel cell stack.

Description

The present invention relates to a male element for at least one header of a fuel cell stack for influencing and optimizing an inflow within the fuel cell stack.

Fuel cells are increasingly used in vehicles. Today's main channels of fuel cell stacks, the so-called headers, on the input and output side of the fuel cell stack have a constant cross section. This has, for example, the disadvantage that, in particular for the rapid heating of the fuel cell system during a cold start, the coolant quantity in the system is unnecessarily large, which can considerably increase the heating time of the fuel cell stack.

Due to the constant cross-section, unfavorable flow conditions also result within the header, which can lead to the system not becoming operationally warmed up immediately and the maximum power being delayed in time. A constant cross section in a header is thus advantageous neither for optimum flow nor for a short heating behavior.

DE 101 488 88 A1 discloses a method and apparatus for operating a fuel cell. The fuel cell comprises a fluid-carrying volume, which can be changed by a movable piston.

WO2006016281A2 discloses a disposable fuel cell with or without a cartridge for receiving fuel cell fuel and a method of utilizing the disposable fuel cell and the cartridge. The disposable fuel cell comprises a variable volume in which a fuel is stored.

US7968242B2 discloses an on-board fuel cell system and a method of venting hydrogen gas. The fuel cell system comprises a means for adjusting a volume flow with a variable volume.

Headers of conventional fuel cell stacks have an adverse flow pattern. Due to a disproportionately large flow rate of coolant, the fuel cell stacks have a relatively long warm-up time.

The invention is therefore based on the object to propose a device for optimizing a flow in a header of a fuel cell stack.

The subject of the present invention is a plug-in element for at least one header of a fuel cell stack, in particular for an input header and / or an output header of the fuel cell stack. According to the invention, the male member has an elongated shape and is positionable in the header, wherein an inflow of fluid through the header to individual cells of the fuel cell stack along an extension of the header can be influenced by the male member.

An incoming flow characterizes a flow of a respective fluid in the direction of individual cells of the fuel cell stack or a flow of a respective fluid impinging on the individual cells. For example, a fuel cell stack may include headers on an input side and an output side. In particular, the fuel cell stack may each have a header for supplying and discharging a liquid or gaseous coolant, air or, for example, a hydrogen gas. By introducing the male element according to the invention into one or more headers of the fuel cell stack, a cross section of the at least one header can be adjusted along its elongated extent. In particular, by adjusting the cross section of the at least one header, an optimized flow profile of the fluid guided through the header can be realized. The male element can influence an inflow to individual cells of the fuel cell stack and optimize the flow. In particular, an amount of medium directed by the at least one header can be reduced. Thus, an unused or so-called dead fuel quantity can be reduced on the hydrogen side, so that, for example, in the case of an accident, an amount of escaping hydrogen can be reduced. With a header for guiding air, the amount of air for a shutdown process of the fuel cell stack can be reduced. The required air should be minimal when stopping the fuel cell stack. By reducing a necessary amount of coolant in the respective fuel cells, for example, a heating behavior of the fuel cell stack can be accelerated.

The plug-in element can be used for example in a mounting of the fuel cell in one or more headers. The male member may be immovably positioned in the at least one header or movable along an elongated extent of the header. For example, the male member may have an equal length for this purpose, such as an elongated extension of the header or shorter than the header. In addition to an optimization of a flow of the guided through the header fluid is increased or reduced by the male member, a flow rate of the fluid through the header and thus also through the fuel cell stack. In this way, a heating behavior of the fuel cell stack can be accelerated in time.

According to one embodiment of the invention, the male element has a round, angular, oblong, or oval cross-section. The male member may thereby have an adapted cross section, which can passively act on the fluid passed through the header. For example, the fluid flow around the male element at least on one side and thus be at least partially deflected. Depending on the requirements of the fuel cell stack, for example, a turbulent or laminar flow within the header can be realized. For example, the male member can also be designed such that it can be positioned in headers with different cross sections. In this way, a universal usability of a male element can be realized.

According to a further embodiment of the invention, the male element has a varying cross-section over its elongated extent. As a result, for example, in an input header in the flow direction, a cross section for guiding the fluid through the male member can be reduced continuously, since the number of cells in the flow direction of the input header decreases and thus the necessary amount of coolant is always lower. In the output header, the cross section for guiding the fluid through the male member in the flow direction can increase steadily. Due to the increasing number of cells in the flow direction, the amount of coolant conveyed here must also increase. This may also be transferred to any guided fluids, such as air or hydrogen gas.

According to a further advantageous embodiment of the invention, the cross section of the male element decreases along its elongated extent. In particular, the cross-section of the male member may be linearly tapered. As a result, the cross section of the header for guiding a fluid can be optimally adapted to a total size of the fuel cell stack. For example, the cross-section may increase or decrease quadratically along the elongate extent of the male member. An insert with a linearly tapered shape can be made particularly technically simple. The flow of the fluid can be reduced or increased linearly along its elongated extent by the header. Alternatively or additionally, the male member perforations, corrugations, guide channels and the like.

According to a further embodiment of the invention, the cross section of the male element is at least partially adapted to a cross section of the header. Thus, the male member can be accurately integrated or inserted into at least one header of the fuel cell stack. A plug-in element adapted to a cross section of the header can preferably completely seal off a partial volume of the header against the fluid and thus release a defined partial volume of the header for flow-optimized routing of the fluid.

According to a further embodiment of the invention, the male member is positively inserted in at least one header or secured in at least one header. Depending on the requirements of the fuel cell stack, for example, the male element can be arranged only in an input header or only in an output header for guiding a coolant. In this way, for example, a targeted flow of a coolant of the fuel cell stack can be optimized so that the fuel cell stack can reach an operating temperature temporally faster even at low ambient temperatures. The male member can be inserted here, for example, in the header fit without additional fasteners or positively inserted in at least one header. Alternatively, the male member may be disposed and fixed in the header by gluing, welding, soldering or screwing. In this case, the male element may preferably have a cross section which is slightly smaller than a cross section of the at least one header. Alternatively, the male member may be the same length as the at least one header and may be fixed in the at least one header by a faceplate and an endplate in position within the at least one header.

According to a further preferred embodiment of the invention, the male member is hollow in its interior or formed of a solid material. As a result, the male element can be produced by means of different methods. For example, the male member may be molded and manufactured by casting or injection molding or by a forming process. The male element can be made particularly easy if it is hollow in its interior.

According to a further advantageous embodiment of the invention, the male element is made of a plastic, a metal or a ceramic. Depending on the requirements and the embodiment of the fuel cell stack, the male element may for example consist of an electrically non-conductive material. Especially at High-temperature fuel cells, the male member must also be able to withstand the operating temperatures of the fuel cells, so that a male made of a ceramic insert can be advantageous.

According to a further embodiment of the invention, the male element has a coating. For example, the male member may be made of a metal and protected by an electrically non-conductive coating against undesirable interactions with electrodes of the fuel cell stack. Alternatively or additionally, the male member may have a slip coating or a heat protection coating.

According to a further embodiment of the invention, the male element consists of at least one electrically non-conductive material. In particular, the male member may consist of a plastic or of a combination with a plastic. As a result, the male element can at least partially have an electrical insulation, which can be applied, for example, by means of an injection molding process. As a result, it is also possible to produce a plug-in element consisting of a plurality of materials in a technically simple manner.

• 1 in einem Querschnitt einen Brennstoffzellenstapel;
• 2 in einer perspektivischen Darstellung den Brennstoffzellenstapel aus der 1;
• 3 in einer perspektivischen Darstellung den Brennstoffzellenstapel aus 1 und 2 mit einem eingelegten Einsteckelement gemäß einer Ausführungsform der Erfindung;
• 4 in einer perspektivischen Darstellung eine Ausführungsform des erfindungsgemäßen Einsteckelements im Header

The invention is schematically illustrated by means of embodiments in the drawings and will be further described with reference to the drawings. It shows:

• 1 in a cross section a fuel cell stack;
• 2 in a perspective view of the fuel cell stack from the 1 ;
• 3 in a perspective view of the fuel cell stack 1 and 2 with an inserted male member according to an embodiment of the invention;
• 4 in a perspective view of an embodiment of the male element according to the invention in the header

In the figures, the same constructive elements each have the same reference numerals.

1 shows a cross section of a fuel cell stack 1 , The fuel cell stack 1 points to an entry page 2 a header, a so-called input header, and on an opposite output side 4 a header, a so-called output header. On the entry side 2 is in a header 6 Air in the fuel cell stack 1 initiated. In two more headers 8th and 10 becomes hydrogen gas (eg in header 8th ) and coolant (eg in headers 10 ) the fuel cells 12 fed. On the exit side 4 can by corresponding header 16 . 18 and 20 Air (eg by header 16 ), Hydrogen gas (eg by header 18 ) and coolant (eg by header 20 ) from the fuel cell stack 1 escape or be led out.

In the 2 is a perspective view of the fuel cell stack 1 shown. To illustrate a form of a header is an output header 16 highlighted for air. The header 16 for leading air out of the fuel cell stack 1 has an elongated shape with a rectangular partially rounded cross-section. The other headers 6 . 8th . 10 . 18 . 20 are also elongated. According to the embodiment, all headers 6 . 8th . 10 . 16 . 18 . 20 a similar elongated extension. The headers 10 . 20 for supplying or discharging coolant and the headers 8th for supplying hydrogen gas have here, for example, a triangular cross-section.

3 shows in a perspective view of the fuel cell stack 1 from the 1 and 2 with one in the output header 16 for air inserted plug-in element 22 , The male element 22 has an elongated extent, that of the elongated extent of the header 16 equivalent. This allows the male element 22 fit into the header 16 be inserted so that the male element 22 does not have to be locked by additional fasteners. Here is an example only a male element 22 shown. It can work in multiple or all headers 6 . 8th . 10 . 16 . 18 . 20 on this header 6 . 8th . 10 . 16 . 18 . 20 be positioned matched plug-in elements. The arrows illustrate a flow direction or flow direction of the coolant through the headers 10 . 20 and through the fuel cells.

The 4 shows a perspective view of the male element according to the invention 22 in the header 16 , According to the embodiment, the male member 22 an elongated extension. The male element 22 partially has a cross-section, which is a cross section of the header 16 equivalent. The male element 22 has a linearly increasing cross-section in the flow direction. This can with increasing number of fuel cells 12 a flow rate can be increased linearly and thus linearly to a number of fuel cells 12 be adjusted. Due to the tapered shape of the male element 22 can be from the fuel cells 12 In addition, air guided out of the fuel cell stack optimized for flow 1 be steered.

LIST OF REFERENCE NUMBERS

1

fuel cell stack

2

Input header / input side

4

Output header / output side

6

Entrance header for air

8th

Input header for hydrogen gas

10

Input header for coolant

12

fuel cells

16

Exit header for air

18

Output header for hydrogen gas

20

Output header for coolant

22

male

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 10148888 A1 [0004]
• WO 2006016281 A2 [0005]
• US 7968242 B2 [0006]

Claims (10)

Insertion element (22) for at least one header (6, 8, 10, 16, 18, 20) of a fuel cell stack (1), in particular for at least one input header (2, 6, 8, 10) and / or at least one output header (4, 16, 18, 20), characterized in that the male member (22) has an elongated shape and in which at least one header (6, 8, 10, 16, 18, 20) is positionable, wherein a flow of a fluid through the header (6, 8, 10, 16, 18, 20) along an extension of the header (6, 8, 10, 16, 18, 20) by the male member (22) can be influenced. Insertion element after Claim 1 wherein the male member (22) has a round, angular, oblong or oval cross-section. Insertion element after Claim 1 or 2 wherein the male member (22) has a varying cross-section throughout its elongated extent. Insertion element after Claim 1 , wherein the cross-section of the male member along its elongated extension decreases, in particular linearly tapers along its elongated extent. Insertion element according to one of Claims 1 to 4 , wherein the cross section of the male member (22) is at least partially adapted to a cross section of the header (6, 8, 10, 16, 18, 20). Insertion element according to one of Claims 1 to 5 , wherein the male member (22) in at least one header (6, 8, 10, 16, 18, 20) inserted positively or in the at least one header (6, 8, 10, 16, 18, 20) is attached. Insertion element according to one of Claims 1 to 6 , wherein the male member (22) is hollow or made of a solid material. Insertion element according to one of Claims 1 to 7 , wherein the male member (22) is made of a plastic, a metal or a ceramic. Insertion element according to one of Claims 1 to 8th wherein the male member (22) has a coating. Insertion element according to one of Claims 1 to 9 , wherein the male member (22) consists of at least one electrically non-conductive material.

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