Fuel Cell System With Improved Separation Between Coolant Media And Hydrogen

Abstract

A fuel cell system includes a fuel cell stack, a housing, a first coolant port, a second coolant port, and a cooling device having a coolant pump and a heat exchanger in fluid communication with the coolant pump. The housing includes an upper side and a bottom side. The fuel cell stack is arranged inside the housing. The first coolant port and the second coolant port each comprise a coolant tube having an inner tube, an outer tube and a gap therebetween. Each of the first coolant port and the second coolant port reach through the housing in a way that an inner end is further to the upper side than an outer end. The first coolant port and the second coolant port are coupled to the cooling device and a first coolant path of the fuel cell stack to form a coolant loop.

Claims

1. A fuel cell system, comprising: a fuel cell stack, a housing, a first coolant port, a second coolant port, and a cooling device having a coolant pump and a heat exchanger in fluid communication with the coolant pump, wherein the housing comprises an upper side and a bottom side, wherein the fuel cell stack is arranged inside the housing, wherein the first coolant port and the second coolant port each comprise a coolant tube having an inner tube, an outer tube and a gap between the inner tube and the outer tube, wherein each of the first coolant port and the second coolant port reach through the housing in an inclined way such that an inner end is further to the upper side than an outer end, and wherein the first coolant port and the second coolant port are coupled to the cooling device and a first coolant path of the fuel cell stack to form a coolant loop.

2. The fuel cell system of claim 1, wherein the coolant pump and the heat exchanger are arranged outside the housing.

3. The fuel cell system of claim 1, wherein the first coolant port is arranged downstream the coolant pump, wherein the inner tube of the first coolant port is in fluid communication with the coolant pump and connected to a first inlet of the first coolant path, and wherein the inner tube of the second coolant port is connected to a first outlet of the first coolant path and in fluid communication with the heat exchanger.

4. The fuel cell system of claim 1, further comprising a hydrogen recirculation pump in fluid communication with an anode outlet and an anode inlet of the fuel cell stack, wherein the hydrogen recirculation pump comprises a second coolant path having a second coolant inlet and a second coolant outlet, and wherein the second coolant inlet and the second coolant outlet are arranged in a bypass of the coolant loop.

5. The fuel cell system of claim 4, wherein a section of the recirculation pump containing the second coolant path is arranged on the outer side of the housing, and wherein a section of the recirculation pump in contact with hydrogen is arranged inside the housing.

6. The fuel cell system of claim 1, wherein the housing comprises a hydrogen discharge opening in or adjacent to the upper side.

7. The fuel cell system of claim 1, wherein at least one of the first coolant port, the second coolant port and coolant leading components of the coolant loop comprises a fire shield.

8. The fuel cell system of claim 7, wherein the fire shield comprises a coating and/or an additional metal shield.

9. The fuel cell system of claim 1, wherein at least one hydrogen handling balance of plant component is arranged inside the housing to supply hydrogen to the fuel cell stack.

10. The fuel cell system of claim 1, further comprising at least one leakage sensor configured for detecting coolant, wherein the at least one leakage sensor is in communication with a signaling device for indicating a leakage, and wherein the at least one leakage sensor is in fluid communication with the gap of the first coolant port and/or the second coolant port.

11. A vehicle comprising at least one electric consumer and at least one fuel cell system of claim 1.

12. The vehicle of claim 11, wherein the vehicle is an aircraft.

13. The vehicle of claim 12, wherein the at least one fuel cell system is arranged in a pressurized area of the aircraft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the following, the attached drawings are used to illustrate exemplary embodiments in more detail. The illustrations are schematic and not to scale. Identical reference numerals refer to identical or similar elements. They show:

[0022] FIGS. 1a, 1b a fuel cell system,

[0023] FIG. 2 the fuel cell system including peripheral components, and

[0024] FIG. 3 an aircraft.

DETAILED DESCRIPTION

[0025] FIG. 1a shows a fuel cell system 2, comprising a fuel cell stack 4, a housing 6, a first coolant port 8 and a second coolant port 10. The fuel cell stack 4 comprises a plurality of individual fuel cells, which are not shown in detail herein. The fuel cell stack 4 is supplied with hydrogen from a hydrogen source 12 as well as air from an air source 14, which are connected to the fuel cell stack 4 and partially reach through the housing 6. A cooling device 16 is provided, which comprises a coolant pump 18 and a heat exchanger 20, which are coupled with the first coolant port 8 and the second coolant port 10. The coolant ports 8 and 10 are connected to a first coolant path 22 inside the fuel cell stack 4. Thus, a coolant loop is provided.

[0026] The housing 6 defines an interior space 24, in which a hydrogen enriched atmosphere may be present during the operation of the fuel cell stack 4. The hydrogen source 12 may comprise an arrangement of valves, supply lines, sensors etc., wherein as many hydrogen handling components as possible are arranged inside the interior space 24 to provide a separation between coolant and hydrogen.

[0027] The first coolant port 8 is a double-walled pipe and has an inner tube 26 and an outer tube 28, which are shown in a magnified view in FIG. 1b. The inner tube 26 and the outer tube 28 are preferably arranged concentrically inside each other. The outer tube 29 exemplarily comprises a fire shield 29 in form of a metal foil. However, also a coating of a non-metallic material may be possible.

[0028] An inner end 30 of the first coolant port 8 is arranged further to an upper side 32 of the housing 6 than an outer end 34, wherein the upper side 32 is opposite to a bottom side 33. The same applies for the second coolant port 10. Hence, the first coolant port 8 and the second coolant port 10 are inclined, such that coolant, which reaches a gap 36 between the inner tube 26 and the outer tube 28 flows out of the housing 6 driven by gravity alone.

[0029] The inner tube 26 is connected to a coolant supply line 38, which is arranged downstream the coolant pump 18, which in turn is arranged downstream of and in fluid communication with the heat exchanger 20. The inner tube 26 of the second coolant port 10 is connected to the heat exchanger 20. Thus, the first coolant port 22 leads to heating up the coolant, which then flows through the heat exchanger 20 to dissipate heat. The coolant pump 18 pumps the chilled coolant with the coolant supply line 38 into the inner tube 26, which then reaches the first coolant path 22 again. This is conducted continuously, to provide a continuous cooling of the fuel cell stack 4.

[0030] At the upper side 32 of the housing 6, a hydrogen outlet 40 is provided. Here, a discharge pipe 42 may be arranged, which lets hydrogen flow out of the interior space 24 into the surrounding or to a further distanced location. As hydrogen is lighter than air, it automatically reaches the hydrogen outlet 40.

[0031] As also shown in FIG. 2, the fuel cell system 2 comprises a hydrogen recirculation pump 56, which has a second coolant path 57 having a second coolant inlet 59 and a second coolant outlet 61, wherein the second coolant path 57 is coupled with a bypass 54 of the coolant supply line 38. Thus, the hydrogen recirculation pump 56 can also be cooled through the coolant.

[0032] Exemplarily, a leakage sensor 35 is arranged in the gap 36 and coupled with a signaling device 37, which may be a screen for indicating a potential leakage to a user of the fuel cell system 2 or of another entity, in which the fuel cell system 2 is installed.

[0033] FIG. 2 shows the fuel cell system 2 in further detail. Here, a fuel cell 44 is shown very schematically in a block-oriented illustration. It comprises an anode 46, a cathode 48, the first cooling path 22 and an electric connection arrangement 50, which represents an electrical interface, i.e. connection terminals, to be connected with a power bus or rail. An electric consumer 52 is connected to the fuel cell 44 and is supplied with an electric current.

[0034] The first cooling path 22 is coupled with the coolant pump 18 and the heat exchanger 20. Between the first cooling path 22 and the coolant pump 18, a bypass 54 is arranged, which allows to cool a hydrogen recirculation pump 56. The hydrogen recirculation pump 56, in turn, allows to recirculate excess hydrogen from an anode outlet 58 back into a supply flow of hydrogen into an anode inlet 60. Upstream of the hydrogen recirculation pump 56, a water separator 62 is arranged, which is designed for removing water from anode exhaust gas. A purge valve 64 allows to actively purge the anode 46, wherein the purge valve 64 is coupled with the hydrogen outlet 40, i.e. the outlet pipe 42.

[0035] A hydrogen supply valve 66 is arranged downstream the hydrogen source 12 and allows to selectively supply hydrogen to the anode inlet 60. The cathode 48 receives air from the air supply 14, wherein a humidifier 68, humidifies the supplied air using humid cathode exhaust gas 70 from the cathode 72 . The air supply can be interrupted through a first shut-off valve 74, which is arranged directly upstream of a cathode inlet 76. The cathode outlet 72 is directly coupled with a second shut-off valve 78. Excess exhaust is discharged through an exhaust outlet 80. It is conceivable that the housing 6 encloses the majority of the components related to hydrogen handling, such as the supply valve 66, the hydrogen recirculation pump 56, the water separator 62 and the purge valve 64.

[0036] FIG. 3 shows an aircraft 82, which comprises a fuselage 84, which is pressurized. The fuel cell system 2 may be arranged inside the pressurized fuselage 84.

[0037] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

Reference Numerals

[0038] 2 fuel cell system [0039] 4 fuel cell stack [0040] 6 housing [0041] 8 first coolant port [0042] 10 second coolant port [0043] 12 hydrogen source [0044] 14 air source [0045] 16 cooling device [0046] 18 coolant pump [0047] 20 heat exchanger [0048] 22 first coolant path [0049] 24 interior space [0050] 26 inner tube [0051] 28 outer tube [0052] 30 inner end [0053] 32 upper side [0054] 33 bottom side [0055] 34 outer end [0056] 35 leakage sensor [0057] 36 gap [0058] 37 signaling device [0059] 38 coolant supply line [0060] 40 hydrogen outlet [0061] 42 discharge pipe [0062] 44 fuel cell [0063] 46 anode [0064] 48 cathode [0065] 50 electric connection arrangement [0066] 52 electric consumer [0067] 54 bypass [0068] 56 hydrogen recirculation pump [0069] 58 anode outlet [0070] 59 second coolant inlet [0071] 60 anode inlet [0072] 61 second coolant outlet [0073] 62 water separator [0074] 64 purge valve [0075] 66 hydrogen supply valve [0076] 68 humidifier [0077] 70 cathode exhaust gas [0078] 72 cathode outlet [0079] 74 first shut-off valve [0080] 76 cathode inlet [0081] 78 second shutoff-valve [0082] 80 exhaust outlet [0083] 82 aircraft [0084] 84 fuselage