Chemistry: electrical current producing apparatus – product – and – With pressure equalizing means for liquid immersion operation
Reexamination Certificate
2000-10-30
2003-05-06
Chaney, Carol (Department: 1745)
Chemistry: electrical current producing apparatus, product, and
With pressure equalizing means for liquid immersion operation
C429S010000, C429S010000, C429S006000
Reexamination Certificate
active
06558832
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The subject matter of the patent application relates to a fuel cell module having at least two fuel cells, in particular low-temperature fuel cells.
It is known that electrical energy can be produced by so-called fuel cells. The fuel cells, or a large number of fuel cells that form a fuel cell module, can be used as a mobile, a stationary or a local power supply. It is already known for fuel cells to be used in motor vehicles, as is described, for example, in German Patent DE 43 22 765 C1.
So-called low-temperature fuel cells, which operate at a temperature of about 80° C., are used in the area of motor vehicle technology. A fuel cell has two electrodes of different polarities. An electrolyte is disposed between the electrodes. The electrolyte in a low-temperature fuel cell may, for example, be a proton-conducting electrolyte membrane (PEM). The fuel cell is fed with a fuel, in particular hydrogen or methanol, and an oxidant, in particular oxygen, separately from one another. In the PEM fuel cell, the positive hydrogen ions, that is to say the protons, migrate through the electrolyte membrane. On the opposite side of the electrolyte membrane, the hydrogen ions react with oxygen. The excess electrons on the hydrogen side of the membrane and the shortage of electrons on the oxygen side produce a potential difference. If an external circuit is formed, then a current can flow.
It is known for a fuel cell module to contain at least two fuel cells, which are separated from one another by a so-called bipolar plate. The fuel cells are in this case disposed such that the anode of one fuel cell is connected via the bipolar plate to a cathode of an adjacent fuel cell. The individual fuel cells in a fuel cell module are electrically connected in series. Apart from providing the electrical connection between the cathode and the anode of adjacent fuel cells, the bipolar plate is also used to separate the fuel and the oxidant. The bipolar plate may be formed by two corrugated metal sheets which are disposed one above the other and between which a smooth metal sheet is disposed. Together with the smooth metal sheet, the corrugated metal sheets bound channels through which the fuel or the oxidant is passed. The fuel and the oxidant preferably flow in directions approximately at 90° to one another.
Bipolar plates are also known which are of integral construction and have channels for the fuel and the oxidant.
The fuel cells in such a stack are mechanically stressed with respect to one another, with the aim of ensuring that there are no gas leaks even at the operating temperature of the fuel cell module. To this end, the fuel cells are disposed between two plates, which are connected to one another via tie rods.
The electrical losses in the fuel cell module are also governed by the electrical connection between the electrodes and the bipolar plate.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a fuel cell module which overcomes the above-mentioned disadvantages of the prior art devices of this general type, in which the electrical losses in the fuel cell module are reduced.
With the foregoing and other objects in view there is provided, in accordance with the invention, a fuel cell module formed of at least two fuel cells. Each of the fuel cells has two electrodes of different polarities and an electrolyte disposed between the electrodes. The electrodes of different polarities are electrically connected to one another. The fuel cells are disposed substantially alongside one another and the electrolyte in each of the fuel cells is disposed substantially in a common plane. At least one fuel supply channel fluidically communicating with the fuel cells and at least one oxidant supply channel fluidically communicating with the fuel cells are provided.
The fuel cell module according to the invention has at least two fuel cells, in particular low-temperature fuel cells, preferably fuel cells with a proton-conducting electrolyte membrane. Each of the fuel cells has two electrodes of different polarities and an electrolyte disposed between the electrodes. At least one fuel supply channel is provided for supplying the fuel cells with a fuel. Each fuel cell is connected to at least one oxidant supply channel, to provide an oxidant.
The electrodes of different polarity in the fuel cell module according to the invention are electrically connected to one another. The at least two fuel cells are disposed essentially alongside one another. The fuel cells are disposed in such a way that the electrolytes in each cell essentially lie in a common plane. This configuration of the fuel cell module according to the invention makes it possible to dispense with bipolar plates, as they are known in a fuel cell module according to the prior art. The individual fuel cells are electrically connected via a connecting element. The electrical losses in the fuel cell module are less than those in a fuel cell module as is known from the prior art, since the electrical contact between the electrodes and the connecting elements is independent of the contact pressure. The electrical contact between the connecting elements and the respective electrodes can be provided, for example, by soldering.
One advantageous refinement of the fuel cell module according to the invention proposes that the fuel cells are disposed alternately such that the electrodes of different polarity in adjacent fuel cells essentially lie in a common plane. This refinement of the fuel cell module according to the invention results in a reduction in the length of the connecting elements which connect the electrodes of different polarity, so that the resistive losses of the connecting elements are reduced, with the connecting element having the same cross-sectional size.
Yet another advantageous refinement of the fuel cell module proposes that the at least two fuel cells are disposed essentially alongside one another, preferably directly alongside one another, and form a row.
A fuel cell module preferably has two rows. The rows of the fuel cell module are preferably connected in parallel. Each row should in this case be of the same voltage. This refinement of the fuel cell module makes it possible to vary the power of the fuel cell module for a predetermined voltage.
Yet another advantageous refinement of the fuel cell module proposes that at least two rows are disposed one above the other, such that they are electrically isolated from one another. This advantageous refinement results in the fuel cell module having a relatively compact construction. Such a configuration of the fuel cell module is particularly suitable for motor vehicles, since the space required for the fuel cell module is relatively small.
For a further compact construction of the fuel cell module, the invention proposes that the fuel cells are disposed essentially parallel to one another.
Depending on the available installation space, the fuel cell module may also be configured such that the fuel cells are disposed essentially on the circumference of a circle. Other configurations of the arrangement of the fuel cells are possible. It is not essential for all the fuel cells to be disposed parallel or on the circumference of a circle. The arrangement of the fuel cells in each row may be the same, so that fuel cell modules of different power can be produced easily and at low cost. It is not essential for the fuel cells in the individual rows to be disposed in the same way. The individual rows may also have a different number of fuel cells.
A further advantageous refinement of the fuel cell module according to the invention proposes that each fuel cell has a fuel feed channel and an oxidant feed channel. The fuel feed channels of the fuel cells are connected to the fuel supply channel, and the oxidant feed channels of the fuel cells are connected to the oxidant supply channel. The fuel cells are disposed between the fuel supply channel and the oxidant supply channel. The fuel cells can also be disposed directly,
Bergmann Andreé
Brück Rolf
Konieczny Jörg-Roman
Chaney Carol
Emitec Gesellschaft fur Emissionstechnologie mbH
Greenberg Laurence A.
Locher Ralph E.
Scaltrito Donald V.
LandOfFree
Fuel cell module does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fuel cell module, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel cell module will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3048274