Heat exchanger and fuel cell system

Abstract

A heat exchanger for a fuel cell system, in particular in a vehicle, includes a gas section for at least one gas and one cooling fluid section for cooling the at least one gas, a housing, and a cooler matrix which is arranged in the housing and in which the cooling fluid section is configured, where the cooler matrix forms a multiplicity of cavities which produce the gas section, at least one gas inlet on the housing, at least one partition in the cooler matrix for dividing the gas section into at least two flows, with the result that the two flows can be cooled by way of the same cooling fluid section, and at least two gas outlets on the housing, where each flow opens into a dedicated gas outlet.

Claims

1. A fuel cell system for a vehicle, comprising: a fuel cell; a compressor; an air path from the compressor to a cathode side of the fuel cell; and a heat exchanger disposed in the air path, wherein the heat exchanger includes a housing, a cooler matrix disposed in the housing, and a partition disposed in the cooler matrix; wherein a fuel cell air channel is partitioned off in the cooler matrix by the partition and wherein air from the fuel cell air channel is suppliable to the cathode side of the fuel cell; wherein a compressor cooling air channel is partitioned off in the cooler matrix by the partition and wherein air from the compressor cooling air channel is suppliable to the compressor.

2. The fuel cell system as claimed in claim 1, wherein: a prechamber is formed in the housing upstream of the cooler matrix; the fuel cell air channel is partitioned off from the compressor cooling air channel within the prechamber; and a nozzle is disposed in the prechamber for injecting water into the fuel cell air channel.

3. The fuel cell system as claimed in claim 1 further comprising an exhaust gas path for exhaust gas from the fuel cell, wherein an exhaust gas channel through which the exhaust gas path runs is partitioned off in the cooler matrix.

4. The fuel cell system as claimed in claim 3, wherein water is separable off from the exhaust gas in or downstream of the exhaust gas channel.

5. The fuel cell system as claimed in claim 1 further comprising an exhaust gas path for exhaust gas from the fuel cell, wherein a membrane humidifier is integrated in the housing so as to join the fuel cell air channel and wherein the exhaust gas path runs through the membrane humidifier.

6. The fuel cell system as claimed in claim 1, wherein the partition extends through and/or across several cavities of the cooler matrix.

7. The fuel cell system as claimed in claim 1, wherein the fuel cell air channel and the compressor cooling air channel are separated from one another by the partition over an entire length.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a fuel cell system according to the invention having a heat exchanger according to the invention as per a first exemplary embodiment;

(2) FIG. 2 shows two views of the heat exchanger according to the invention as per the first exemplary embodiment;

(3) FIG. 3 shows the fuel cell system according to the invention having the heat exchanger according to the invention as per a second exemplary embodiment;

(4) FIG. 4 shows the fuel cell system according to the invention having the heat exchanger according to the invention as per a third exemplary embodiment; and

(5) FIG. 5 shows two views of the heat exchanger according to the invention as per the third exemplary embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) FIGS. 1 to 5 show, in different exemplary embodiments and in schematic views, a heat exchanger 2 in a fuel cell system 1. In each case only those components of the fuel cell system 1 that are necessary for explaining the invention are shown. The fuel cell system 1 is used in particular in a vehicle.

(7) In all of the exemplary embodiments, identical or functionally identical components are denoted by the same reference designations.

(8) FIG. 1 shows the fuel cell system 1 according to the first exemplary embodiment. The fuel cell system 1 comprises at least one fuel cell 3. In particular, several of the fuel cells 3 are arranged in a stack. The fuel cell system 1 furthermore comprises a compressor 4, the heat exchanger 2, an air path 5 and a compressor cooling air return line 11.

(9) The compressor 4 draws in ambient air axially and discharges the compressed air via a compressor outlet 7. Furthermore, the compressor 4 has a corresponding inlet and outlet for the compressor cooling air return line 11.

(10) The heat exchanger 2 comprises a housing 12. An air inlet 8 (referred to generally as gas inlet) is formed on the housing 12. A fuel cell air outlet 9 and a compressor cooling air outlet 10 (referred to generally as gas outlets) are situated on the opposite side of the housing 12.

(11) Furthermore, a cooling fluid inlet 20 and a cooling fluid outlet 21 are formed on the housing 12. A corresponding cooling fluid flows via the cooling fluid inlet 20 into the heat exchanger 2 and exits the heat exchanger 2 via the cooling fluid outlet 21. Thus, a cooling fluid path 22 of the heat exchanger 2 runs via the cooling fluid inlet 20 and the cooling fluid outlet 21.

(12) The air path 5 of the fuel cell system 1 leads from the compressor outlet 7 to the air inlet 8 of the heat exchanger 2, through the heat exchanger 2 and from the fuel cell air outlet 9 to the cathode side of the fuel cell 3.

(13) The compressor cooling air return line 11 leads from the compressor cooling air outlet 10 back to the compressor 4.

(14) An exhaust gas path 6 leads from the fuel cell 3 into the surroundings.

(15) FIG. 2 shows, in two different illustrations, the construction of the heat exchanger 2 in detail. The left-hand illustration in FIG. 2 shows a longitudinal section through the heat exchanger 2. The right-hand illustration in FIG. 2 shows the section A:A indicated on the left-hand illustration.

(16) The housing 12 of the heat exchanger 2 comprises a prechamber 13 and an end piece 15. A central piece 14 of the housing 12 is arranged between the prechamber 13 and the end piece 15.

(17) A cooler matrix 17 of the heat exchanger 2 is positioned in the central piece 14 of the housing 12. The cooler matrix 17 is connected in fluid-conducting fashion to the cooling fluid inlet 20 and to the cooling fluid outlet 21. The cooler matrix 17 thus forms the cooling fluid path 22 between cooling fluid inlet 20 and cooling fluid outlet 21.

(18) Various cooling elements 18 may be provided in the cooler matrix 17. The cooling elements 18 are for example tubes or plates, wherein the cooling fluid flows in the tubes or between the plates. Furthermore, the cooling elements may also be formed by thin cooling ribs or sheets in which no cooling fluid flows but which are continuously cooled by the cooling fluid.

(19) The cooler matrix 17 forms a multiplicity of cavities 19. The cavities 19 are situated in particular between the individual cooling elements 18 of the cooler matrix 17. The entirety of the cavities 19 constitutes the gas path. The gas in the gas path is cooled by the cooler matrix 17.

(20) In the two sectional illustrations in FIG. 2, the cooler matrix 17 is divided by a partition 23 into two channels. These are a fuel cell air channel 24 and a compressor cooling air channel 25. The partition 23 extends over the entire length and width of the cooler matrix 17. The two channels 24, 25 are thus entirely separated from one another.

(21) The air compressed by the compressor 4 flows into the prechamber 13 of the housing 12. A guide element 16 is arranged in the prechamber 13. By means of the guide element 16, the inflowing air is divided up between the fuel cell air channel 24 and the compressor cooling air channel 25.

(22) Within the cooler matrix 17, the air is cooled in both channels 24, 25 simultaneously by means of the same cooler matrix 17, by means of the same cooling fluid path 22 and thus by means of the same cooling fluid.

(23) In the end piece 18 of the housing 12, the fuel cell air outlet 9 and the compressor cooling air outlet 10 are formed separately from one another. It is thereby ensured that the air from the fuel cell air channel 24 flows only into the fuel cell air outlet 9, and the air from the compressor cooling air channel 25 flows only into the compressor cooling air outlet 10.

(24) As shown in the section A:A in FIG. 2, the entire cross-sectional area of the cooler matrix 17 is maintained and is divided only by the at least one partition 23. In particular, provision is made here for the cross-section of the cooler matrix 17 to not be narrowed or constricted for the purposes of the division into the individual channels. Rather, the conventional cross-sectional shape, for example the rectangular, circular or oval shape, of a conventional cooler matrix is maintained and is merely divided into channels by the at least one partition 23.

(25) FIG. 3 shows the fuel cell system 1 as per the second exemplary embodiment. In the second exemplary embodiment, the cooler matrix 17 has at least two channels: the fuel cell air channel 24 and an exhaust gas channel 33.

(26) In the second exemplary embodiment, in addition to these two channels 24, 33, the compressor cooling air channel 25 may also be partitioned off, as has been discussed in the context of the first exemplary embodiment. In the context of the second exemplary embodiment, however, in particular the possibility of utilizing the heat exchanger 2 for the condensation of water in the exhaust gas path 6 will be presented.

(27) In the second exemplary embodiment, the exhaust gas path 6 runs through the exhaust gas channel 33 of the heat exchanger 2. For this purpose, the housing 12 of the heat exchanger 2 comprises an exhaust gas inlet 26 and an exhaust gas outlet 27.

(28) In the exemplary embodiment shown, the fuel cell air channel 24 and the exhaust gas channel 33 run in opposite directions. The two gas flows, specifically the air and the exhaust gas, are strictly separated from one another. Therefore, the exhaust gas inlet 26 is separated from the fuel cell air outlet 9. The exhaust gas outlet 27 is separated from the air inlet 8. Nevertheless, the air inlet 8 can be integrated together with the exhaust gas outlet 27, and/or the fuel cell air outlet 9 can be integrated together with the exhaust gas inlet 26, in one housing component.

(29) Downstream of the heat exchanger 2, the exhaust gas path 6 passes through a water separator 28. The water separated off therein is collected in a water collecting vessel 29.

(30) From the water vessel 29, a water line leads to a nozzle 32. A pump 31 and/or at least one filter 30 are advantageously situated in the water line.

(31) The nozzle 32 is situated in the prechamber 13 and is arranged such that the water is injected only into or upstream of the fuel cell air channel 24.

(32) In the case of the water injection being combined with the separate formation of the compressor cooling air channel 25 within the cooler matrix 17, as shown in FIG. 2, the nozzle 32 would be arranged below the guide element 16. It is achieved in this way that the water is injected only into or upstream of the fuel cell air channel 24, and not into the compressor cooling air channel 25.

(33) FIG. 4 shows the fuel cell system 1 as per the third exemplary embodiment. A membrane humidifier 34 is provided in the third exemplary embodiment.

(34) The exhaust gas path 6 runs in this case through the membrane humidifier 34. Furthermore, the air path 5, downstream of the cooler matrix 17, likewise runs through the membrane humidifier 34. In the membrane humidifier 34, the air fed to the fuel cell 3 is humidified by means of the relatively humid exhaust gas.

(35) In the third exemplary embodiment, the cooler matrix 17 is divided into two channels, specifically the fuel cell feed air channel 24 and the exhaust gas channel 33.

(36) FIG. 5 shows the exact construction of the heat exchanger 2 of the third exemplary embodiment. In FIG. 5, the heat exchanger 2 is illustrated in an exploded view in the left-hand illustration. The right-hand illustration shows the assembled heat exchanger 2.

(37) Instead of the end piece 15, the housing 12 comprises the membrane humidifier 34. The fuel cell air outlet 9 is formed at the right-hand end of the membrane humidifier 34. That side of the membrane humidifier 34 which faces toward the cooler matrix 17 extends over the entire cross-sectional area of the fuel cell air channel 24. In this way, the membrane humidifier 34 closes off the housing 12 or the central piece 14 on one side and can thus be used as an integral constituent part of the housing 12.

(38) An intermediate piece 35 is inserted between the membrane humidifier 34 and the central piece 14. The intermediate piece 35 extends as a frame around the entire cross section of the cooler matrix 17. At the end of the compressor cooling air channel 25, the intermediate piece 35 forms a collecting chamber for conducting the air that is to be recirculated to the compressor 4 to the compressor cooling air outlet 10.

LIST OF REFERENCE CHARACTERS

(39) 1 Fuel cell system 2 Heat exchanger 3 Fuel cell 4 Compressor 5 Air path 6 Exhaust gas path 7 Compressor outlet 8 Air inlet (gas inlet) 9 Fuel cell air outlet (gas outlet) 10 Compressor cooling air outlet (gas outlet) 11 Compressor cooling air return line 12 Housing 13 Prechamber 14 Central piece 15 End piece 16 Guide element 17 Cooler matrix 18 Cooling elements 19 Cavities 20 Cooling fluid inlet 21 Cooling fluid outlet 22 Cooling fluid path 23 Partition 24 Fuel cell air channel 25 Compressor cooling air channel 26 Exhaust gas inlet (gas inlet) 27 Exhaust gas outlet (gas outlet) 28 Water separator 29 Water collecting vessel 30 Filter 31 Pump 32 Nozzle 33 Exhaust gas channel 34 Membrane humidifier 35 Intermediate piece

(40) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.