FUEL CELL STACK, FUEL CELL DEVICE AND MOTOR VEHICLE WITH FUEL CELL DEVICE

Abstract

A fuel cell stack includes a plurality of fuel cells arranged in the direction of the stack and tensioned by means of tension elements, of which at least one has a cell voltage tap for electrical connection to a cell monitoring unit, wherein the at least one cell voltage tap is mechanically secured by at least one of the tension elements as regards the connection to the fuel cells. A fuel cell device and a motor vehicle with a fuel cell device are also provided.

Claims

1. A fuel cell stack, comprising: a plurality of fuel cells arranged in the direction of the stack and tensioned by tension elements, wherein at least one of the fuel cells has a cell voltage tap for electrical connection to a cell monitoring unit, and wherein the at least one cell voltage tap is mechanically secured as regards the connection to the fuel cells by at least one of the tension elements.

2. The fuel cell stack according to claim 1, wherein each cell voltage tap comprises a plug connector for a plug-in connection.

3. The fuel cell stack according to claim 2, wherein the plug connectors are pre-assembled on the tensioning element.

4. The fuel cell stack according to claim 1, wherein the tensioning element has pass-throughs for cables routed to the cell monitoring unit.

5. The fuel cell stack according to claim 1, wherein each plug connector is arranged on one of the fuel cells, and wherein a mounting part for the plug connectors is accommodated in the tensioning element for the electrical connections with the cell monitoring unit.

6. The fuel cell stack according to claim 5, wherein the plug connectors are formed by sockets and the mounting part is formed by an injection molded part through which the electrical connections are routed to a printed circuit board which is connected to the cell monitoring unit.

7. The fuel cell stack according to claim 5, wherein the plug connector and the mounting part are integrally combined in one component.

8. The fuel cell stack according to claim 1, wherein the fuel cells are tensioned between end plates by the tension elements which are formed as rigid tension straps.

9. A fuel cell device with a fuel cell stack, comprising: a plurality of fuel cells arranged in the direction of the stack and tensioned by tension elements, wherein at least one of the fuel cells has a cell voltage tap for electrical connection to a cell monitoring unit, and wherein the at least one cell voltage tap is mechanically secured as regards the connection to the fuel cells by at least one of the tension elements.

10. A motor vehicle having a fuel cell device with a fuel cell stack, the motor vehicle comprising: a plurality of fuel cells arranged in the direction of the stack and tensioned by tension elements, wherein at least one of the fuel cells has a cell voltage tap for electrical connection to a cell monitoring unit, and wherein the at least one cell voltage tap is mechanically secured as regards the connection to the fuel cells by at least one of the tension elements.

11. The fuel cell stack according to claim 1, wherein each of the fuel cells has a respective cell voltage tap for electrical connection to the cell monitoring unit.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0017] Further advantages, features and details will be apparent from the claims, from the following description of embodiments and from the drawings.

[0018] FIG. 1 shows a schematic representation of a fuel cell stack, which is made up of a plurality of fuel cells, which are tensioned together by tension elements, which also serve to secure the plug-in connections.

[0019] FIG. 2 shows a representation corresponding to FIG. 1 with plug connectors mounted on the fuel cells, which connectors are connected to the cell voltage monitoring unit by connecting elements associated with a tensioning element.

[0020] FIG. 3 shows a representation corresponding to FIG. 1, in which the plug connector and a mounting part are integrated in a tensioning element.

DETAILED DESCRIPTION

[0021] A fuel cell device has a fuel cell stack 1 with a plurality of fuel cells 2 arranged in the direction of the stack.

[0022] Each of the fuel cells 2 comprises an anode, a cathode and a proton-conducting membrane separating the anode from the cathode. The membrane is formed from an ionomer, such as a sulfonated polytetrafluorethylene (PTFE) or a perfluorinated sulfonic acid (PFSA) polymer. Alternatively, the membrane may be formed as a sulfonated hydrocarbon membrane.

[0023] Fuel, in particular hydrogen, can be supplied to the anode from a fuel tank via an anode chamber. 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 allows the protons to pass through, but it is impermeable to the electrons. The reaction: 2H.sub.2.fwdarw.4H.sup.++4e.sup.− (oxidation/electron release) occurs, for example, at the anode. Whereas the protons pass through the PEM to the cathode, the electrons are routed via an external circuit to the cathode or to an energy storage device.

[0024] The cathode gas (for example, oxygen or oxygen-containing air) can be supplied to the cathode via a cathode chamber, such that the following reaction takes place on the cathode side: O.sub.2+4H.sup.++4e.sup.−.fwdarw.2H.sub.2O (reduction/electron capture).

[0025] The fuel cell stack 1 also has a tensioning device formed by tension elements 3 for pressing the fuel cells 2 together. End plates 4 are assigned to the terminal fuel cells 2, to which plates the tensioning device is connected for the application of force, wherein the media ports 5 (shown only in FIG. 3) for the fuel, the oxidant, and a coolant are arranged on one of the end plates 4 or also on both end plates 4; on the left-hand end plate 4 in the embodiment examples shown in the drawing. The tension elements 3 are formed as rigid tension straps, which can, in particular, be made of metal with the corresponding mechanical properties with regards to strength and flexural rigidity.

[0026] The fuel cell stack 1 may also have a cell voltage tap 6 for each of the fuel cells 2 for electrical connection to a cell monitoring unit 7 in order to enable diagnosis of fault-free operation. The cell voltage taps 6 are mechanically secured as regards the connection to the fuel cells 2 by at least one of the tension elements 3.

[0027] FIG. 1 shows an embodiment in which each cell voltage tap 6 comprises a plug connector 8 for a plug-in connection, such that in this embodiment the focus is on additional mechanical securing. In addition, the plug connectors 8 can also be pre-assembled on the tensioning element 3 such that the tensioning element 3 can be used as an assembly aid, wherein the tensioning element 3 has pass-throughs for cables routed to the cell monitoring unit 7.

[0028] FIG. 2 shows an embodiment in which each plug connector 8 is arranged on one of the fuel cells 2, wherein a mounting part 9 for the plug connectors 8 is accommodated in the tensioning element 3 for the electrical connections to the cell monitoring unit 7, which is to say that the plug connectors 8 are formed by sockets 10 and the mounting part 9 by an injection-molded part 11, through which the electrical connections are routed to a printed circuit board 12, which is electrically and, in particular, mechanically connected to the cell monitoring unit 7.

[0029] FIG. 3 shows an embodiment in which the plug connector 6 and the mounting part 9 are moreover integrally combined in one component 13 that is integrated in the tensioning element 3. The contact on component 13 is implemented with an overhang 14, such that the connection to the cell monitoring unit 7 can be implemented with solder contacts via the printed circuit board 12.

[0030] Fuel cell devices with a fuel cell stack 1 of this type demonstrate their advantages in particular when used in a motor vehicle, since exceptional mechanical loads and vibrations are present there.

[0031] Aspects of the various embodiments described above can be combined to provide further embodiments. 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.