Fuel cell device for a motor vehicle

Abstract

The invention relates to a fuel cell device (12) for a motor vehicle (10), comprising at least one housing (16), wherein a fuel cell stack (20) comprising at least one fuel cell (22) is arranged in an interior space (18) of the housing (16), and wherein a gap (24) is formed between the housing (16) and the fuel cell stack (20), wherein a cooling device (26) is provided which introduces an electrically non-conductive cooling fluid (28) into the gap (24).

Description

[0001] The invention relates to a fuel cell device for a motor vehicle, comprising at least one housing, wherein a fuel cell stack comprising at least one fuel cell is arranged in an interior space of the housing, and wherein a gap is formed between the housing and the fuel cell stack.

[0002] In so-called polymer electrolyte fuel cells, a large amount of heat is generated during the conversion of chemical energy, especially hydrogen and oxygen, into electrical energy, particularly electricity. Above a certain system power output, this heat becomes the limiting factor, as it can no longer be dissipated from the system.

[0003] DE 10 2004 060 344 A1 relates to a dielectric coolant for fuel cells as well as an evaporative cooling process using the same. The coolant comprises an emulsion that defines a polar inner phase and an outer hydrocarbon phase. The polar inner phase comprises an azeotropic mixture containing one or more polar compounds formed from water, alcohol, and combinations thereof.The fuel cell is designed to react with oxygen to generate an electric current and at least one reaction product. It comprises an electrochemical cell for catalytic reaction, configured to include a fuel flow path, an oxygen flow path, and a coolant flow path that is fluidically decoupled from the fuel and oxygen flow paths. This coolant flow path defines a coolant isolating manifold containing the dielectric cooling fluid described above. The method for cooling the fuel cell includes, among other things, evaporating the polar inner phase of the dielectric cooling fluid emulsion within the coolant isolating manifold.

[0004] The object of the present invention is to create a fuel cell device which can be cooled in an improved manner.

[0005] This problem is solved by a fuel cell device according to the independent claim. Advantageous embodiments are specified in the dependent claims.

[0006] One aspect of the invention relates to a fuel cell device for a motor vehicle, comprising at least one housing, wherein a fuel cell stack comprising at least one fuel cell is arranged in an interior space of the housing, and wherein a gap is formed between the housing and the fuel cell stack.

[0007] It is provided that a cooling device is included which introduces an electrically non-conductive cooling fluid into the gap.

[0008] In particular, the fuel cell stacks, also referred to as stacks, have a suitable housing, especially a stack housing, for mechanical protection. The stack housing encloses the fuel cells. In the prior art, the space between the fuel cell stack and the housing is filled with air. In particular, this space corresponds to the gap. According to the invention, this air is replaced with an electrically non-conductive cooling fluid with high heat capacity, for example, dielectric oil.

[0009] This has the particular advantage that higher thermal mass and temperature peaks can be absorbed for a longer period before the fuel cell device needs to enter derating mode. This allows for a higher peak power output from the fuel cell device. Furthermore, the extended cooling circuit enables improved cooling performance. This increases both the maximum continuous power output and the peak power output. If, for example, the fuel cell device has active cooling, such as an air conditioning compressor, it can also be cooled, thus increasing the maximum power output.

[0010] According to an advantageous embodiment, the fuel cell device additionally features a housing cooling system for the housing.

[0011] It is also advantageous if the cooling device has a circulation pump for circulating the electrically non-conductive cooling fluid.

[0012] Another advantageous embodiment provides that the cooling device additionally includes a cooling compressor for actively cooling the electrically non-conductive cooling fluid.

[0013] Furthermore, it has proven advantageous if the housing has an inlet and an outlet for the electrically non-conductive cooling fluid.

[0014] In another advantageous embodiment, the electrically non-conductive cooling fluid is cooled by means of a heat exchanger outside the housing.

[0015] Another aspect of the invention relates to a motor vehicle with a fuel cell device according to the preceding aspect.

[0016] Advantageous designs of the fuel cell device are to be regarded as advantageous designs of the motor vehicle.

[0017] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0018] This shows: Fig. 1 a schematic side view of an embodiment of a motor vehicle with an embodiment of a fuel cell device; and Fig. 2 a schematic side view of an embodiment of a fuel cell device.

[0019] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0020] Fig. Figure 1 shows a schematic side view of an embodiment of a motor vehicle 10. The motor vehicle 10 is powered, in particular, by a fuel cell device 12. The fuel cell device 12 converts hydrogen and oxygen into electrical energy by means of a chemical reaction. The motor vehicle 10 may, for example, have a drive device 14, which is, in particular, at least partially electrical. The current or electrical energy generated by the fuel cell device 12 can be used for the drive device 14 to power the motor vehicle 10.

[0021] Fig. Figure 2 shows a schematic side view of an embodiment of a fuel cell device 12. The fuel cell device 12 has at least one housing 16, wherein a fuel cell stack 20 with at least one fuel cell 22, in this case a plurality of fuel cells 22, is arranged in an interior 18 of the housing 16. A gap 24 is formed between the housing 16 and the fuel cell stack 20.

[0022] The fuel cell device 12 is provided to have a cooling device 26 which introduces an electrically non-conductive cooling fluid 28 into the gap 24. In particular, the cooling device 26 has an inlet 30 and an outlet 32. Furthermore, the cooling device 26 may have a circulation pump 34 for circulating the electrically non-conductive cooling fluid 28. The cooling device 26 may also have a cooling compressor 36 for actively cooling the electrically non-conductive cooling fluid 28. Finally, the electrically non-conductive cooling fluid 28 may be cooled by means of a heat exchanger 38 located outside the housing 16.

[0023] The Fig. Figure 2 further shows that an additional housing cooling system 40 can be provided for cooling the housing 16. For this purpose, an additional inlet 42 and an additional outlet 44 can be provided.

[0024] In particular, this shows that Fig.2, that the housing 16 encloses the fuel cell stack 20 for mechanical protection. In the space between the fuel cell stack 20 and the housing 16, in particular the gap 24 is formed, which is enclosed with the electrically non-conductive cooling fluid 28 with high heat capacity, for example as a dielectric oil.

[0025] For example, the electrically non-conductive coolant 28 can be cooled without circulation and heat dissipation by a vehicle-side heat exchanger, analogous to an oil sump. Alternatively, circulation of the electrically non-conductive coolant 28 can be provided by means of the circulation pump 34, and heat dissipation can be carried out by the vehicle-side heat exchanger 38, analogous to a cooling system for an electric motor. Alternatively once again, the electrically non-conductive coolant 28 can be circulated by the circulation pump 34, and heat dissipation can occur through the vehicle-side heat exchanger 38. Furthermore, cooling can be provided by a chiller or the air conditioning compressor 36. Reference symbol list 10 motor vehicle 12 Fuel cell device 14 Drive device 16 cases 18 Interior 20 fuel cell stacks 22 Fuel cell 24 columns 26 Cooling unit 28 electrically non-conductive cooling fluid 30 inflows 32 Procedure 34 Circulation pump 36 Cooling compressor 38 heat exchangers 40 Case cooling 42 more arrivals 44 further process QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2004 060 344 A1

[0003]

Claims

[1] Fuel cell device (12) for a motor vehicle (10), comprising at least one housing (16), wherein a fuel cell stack (20) with at least one fuel cell (22) is arranged in an interior space (18) of the housing (16), and wherein a gap (24) is formed between the housing (16) and the fuel cell stack (20), characterized by that a cooling device (26) is provided which introduces an electrically non-conductive cooling fluid (28) into the gap (24). [2] Fuel cell device (12) according to claim 1, characterized by that a housing cooling system (40) is additionally provided for the housing (16). [3] Fuel cell device (12) according to one of claims 1 or 2, characterized by that the cooling device (26) has a circulation pump (34) for circulating the electrically non-conductive cooling fluid (28). [4] Fuel cell device (12) according to one of the preceding claims, characterized bythat the cooling device (26) additionally has a cooling compressor (36) for actively cooling the electrically non-conductive cooling fluid (28). [5] Fuel cell device (12) according to one of the preceding claims, characterized by that the housing (16) has an inlet (30) and an outlet (32) for the electrically non-conductive cooling fluid (28). [6] Fuel cell device (12) according to one of the preceding claims, characterized by that the electrically non-conductive cooling fluid (28) is cooled by means of a heat exchanger (38) outside the housing (16).

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