FUEL DEVICE AND THE USE THEREOF IN A MOTOR VEHICLE

Abstract

The present invention relates to a fuel cell device (1) having a fuel cell (2) which, during operation, emits water as a product of cold combustion; a supply air path (3) leading to the fuel cell (2) for a cathode supply air flow (5), which defines a supply air flow direction (4), the cathode supply air flow coming from water-containing supply air supplied to the fuel cell (2); and an exhaust air path (7)leading away from the fuel cell (2), for a cathode exhaust air flow (9), which defines an exhaust air flow direction (8), the cathode exhaust air flow coming from water-containing exhaust air flowing out of the fuel cell (2). The supply air path (3) and the exhaust air path (7) are routed through a humidifier (10) of the fuel cell device (1), which humidifier communicates fluidically with the supply air and the exhaust air, to humidify the supply air and dehumidifying the exhaust air. The exhaust air path (7) is also routed through a water separator (11) of the fuel cell device (1), which water separator communicates fluidically with the exhaust air, for removing water from the exhaust air and for providing this water as evaporation water. The fuel cell device (1) also has a heat exchanger (12) for cooling the fuel cell (2), which heat exchanger has an evaporative cooler (13) for cooling the heat exchanger (12). It is essential that the evaporative cooler (13) is assigned to the water separator (11) in fluidic communication and that it is supplied with evaporation water by same.

Claims

1. A fuel cell device (1), in particular for a motor vehicle, having a fuel cell (2), a supply air path (3) leading to the fuel cell (2) for a cathode supply air flow (5), which defines a supply air flow direction (4), the cathode supply air flow comprising water-containing supply air supplied to the fuel cell (2); and an exhaust air path (7) leading away from the fuel cell (2), for a cathode exhaust air flow (9), which defines an exhaust air flow direction (8), the cathode exhaust air flow comprising water-containing exhaust air flowing out of the fuel cell (2); wherein the supply air path (3) and the exhaust air path (7) are routed through a humidifier (10) of the fuel cell device (1), which humidifier communicates fluidically with the supply air and the exhaust air for humidifying the supply air and dehumidifying the exhaust air; wherein the exhaust air path (7) is routed through a water separator (11) of the fuel cell device (1), which water separator communicates fluidically with the exhaust air for removing water from the exhaust air and for providing this water as evaporation water; having a heat exchanger (12) for cooling the fuel cell (2), which has an evaporative cooler (13) for cooling the heat exchanger (12); wherein the evaporative cooler (13) is assigned to the water separator (11) in fluidic communication and is supplied with evaporation water by same.

2. The fuel cell device (1) according to claim 1, characterized in that the water separator (11) is arranged upstream of the humidifier (10) with respect to the exhaust air flow direction (8) of the cathode exhaust air flow (9); and/or the water separator (11) is arranged downstream of the humidifier (10) with respect to the exhaust air flow direction (8) of the cathode exhaust air flow (9); and/or the water separator (11) is arranged in or downstream of a drive turbine (38) or is formed by same.

3. The fuel cell device (1) according to claim 2, characterized in that the water separator (11), which is arranged upstream of the humidifier (10), is formed by a coarse water separator (14) for removing water from the exhaust air and for providing this water as evaporation water; and/or the water separator (11), which is arranged downstream of the humidifier (10), is formed by a fine water separator (15) for removing water from the exhaust air and for providing this water as evaporation water.

4. The fuel cell device (1) according to any of the preceding claims, characterized in that it has a feed water path (16) leading from the water separator (11) to the evaporative cooler (13) for a feed water flow (18) of evaporation water, which feed water flow defines a feed flow direction (17), for supplying the evaporative cooler (13); or it has a pair of fluidically parallel feed water paths (16, 20) for supplying the evaporative cooler (13), namely a feed water path (16) for a feed water flow (18) of evaporation water, which feed water flow defines a feed flow direction (17), and which leads from the coarse water separator (14) to the evaporative cooler (13), and a further feed water path (20) for a further feed water flow (22) of evaporation water, which feed water flow defines a further feed flow direction (21), and which leads from the fine water separator (15) to the evaporative cooler (13).

5. The fuel cell device (1) according to claim 4, characterized by a valve device (23) for controlling or regulating a mass or volumetric flow of the evaporation water, which valve device allows evaporation water to flow through, and which valve device is fluidically inserted into the feed water flow (18) or into the further feed water flow (22) or into the one feed water flow (18) and the further feed water flow (22) between the evaporative cooler (13) and the water separator (11).

6. The fuel cell device (1) according to claim 4, characterized in that the one valve device (23) is implemented by means of a water feed valve (25), a float valve, a float valve (26) with leakage, a pressure relief valve, a non-return valve, or by a combination of these valves.

7. The fuel cell device (1) according to any of the preceding claims, characterized by a collection volume (27) for collecting evaporation water, which is fluidically connected to the evaporative cooler (13) on one side and to the water separator (11) or the coarse water separator (14) and/or the fine water separator (15) and/or a drive turbine (38) on the other.

8. The fuel cell device (1) according to claim 7, characterized in that the collection volume (27) is formed or delimited by at least one evaporation water line (19) for a feed water flow (18, 22) of evaporation water.

9. The fuel cell device (1) according to claim 7 or 8, characterized by a separate evaporation water tank (28) for collecting evaporation water, which tank supplements or forms or delimits the collection volume (27) and allows evaporation water to flow through, and said tank is fluidically inserted into the feed water flow (18), between the coarse water separator (14) and the evaporative cooler (13); or a separate evaporation water tank (28) for collecting evaporation water, which tank supplements or forms or delimits the collection volume (27) and allows evaporation water to flow through, and the tank is fluidically inserted into the feed water flow (18), between the valve device (23) and the evaporative cooler (13).

10. The fuel cell device (1) according to claim 9, characterized in that the evaporation water tank (28) has a tank collection volume (29) of greater than 0 liters/kW and less than or equal to 0.1 liters/kW of installed electrical output of the fuel cell (2).

11. The fuel cell device (1) according to claim 9 or 10, characterized in that the evaporation water tank (28) is pressurized by means of pressurized supply air from the cathode supply air flow (5) and/or by means of pressurized exhaust air from the cathode exhaust air flow (9).

12. The fuel cell device (1) according to any of claims 9 to 11, characterized in that an air valve (30) is provided for pressurizing the evaporation water tank (28), which air valve connects the cathode supply air flow (5) to the evaporation water tank (28) in fluidic communication, so that supply air can flow through the air valve (30) into the evaporation water tank (28) and pressurize it.

13. The fuel cell device (1) according to any of claims 9 to 12, characterized by a feed valve device (31) for controlling or regulating a mass or volumetric flow of the evaporation water, which feed valve device allows evaporation water to flow through and is fluidically inserted into the one feed water flow (18), between the evaporative cooler (13) and the evaporation water tank (28).

14. The fuel cell device (1) according to claim 13, characterized in that the feed valve device (31) has or is formed by a sprinkler valve (42) for controlling or regulating the mass or volumetric flow of the evaporation water flowing out of the evaporation water tank (28); and/or the feed valve device (31) has or is formed by a conveying device (32) for conveying evaporation water from the evaporation water tank (28) to the evaporative cooler (13); and/or the feed valve device (31) has or is formed by a water outlet valve (33) to discharge evaporation water from the evaporation water tank (28), wherein the water outlet valve (33) is either fluidically arranged directly at the evaporation water tank (28) or is fluidically arranged indirectly at the evaporation water tank (28) via the conveying device (32).

15. The fuel cell device (1) according to claim 9 or 14, characterized in that the conveying device (32) is implemented by means of a delivery pump, particularly a peripheral wheel pump or a side channel impeller.

16. The fuel cell device (1) according to any of the preceding claims, characterized by a compressor system (34) which has a compressor (35) that is or can be operated by exhaust air; wherein the impeller (36) thereof for compressing supply air allows the supply air to flow through and is fluidically inserted into the cathode supply air flow (5) upstream of the fuel cell (2); and wherein the drive turbine (38) thereof for driving the impeller (36) allows exhaust air to flow through and is fluidically inserted into the cathode exhaust air flow (9) downstream of the humidifier (10) or the fine water separator (15).

17. The fuel cell device (1) according to any of the preceding claims, characterized in that the heat exchanger (12) or the evaporative cooler (13) is operated or used at an ambient temperature of the fuel cell device (1) of greater than or equal to 5° C.; or the heat exchanger (12) or the evaporative cooler (13) is operated at a coolant temperature from the fuel cell (2) of greater than or equal to 60° C. or greater than or equal to 70° C. or greater than or equal to 75° C.; or the operation of the heat exchanger (12) or of the evaporative cooler (13) is controlled or regulated by means of a switch-on characteristic, wherein the degree of switch-on z.sub.verd is based on the quantity of heat Q.sub.FC of the fuel cell (2) and the ambient temperature T.sub.Amb in ° C. of the fuel cell device (1) approximately according to the following equation:
Z.sub.Verd≈f(Q.sub.FC/Q.sub.max*55° C./(75° C.−T.sub.Amb)) where f(x)≈0 for x<0.5; or the operation of the heat exchanger (12) or of the evaporative cooler (13) is regulated, wherein the regulation takes place via a demand map with or without taking into account the thermal inertia of the fuel cell device (1); or the operation of the heat exchanger (12) or of the evaporative cooler (13) is regulated, wherein the regulation takes place based on the ambient temperature of the fuel cell device (1) or the ambient temperature of the fuel cell device (1) and humidity or a coolant temperature; or the operation of the heat exchanger (12) or of the evaporative cooler (13) is regulated, wherein the regulation is controlled by a thermostatic valve and/or supported by the activation of a fan; or the operation of the heat exchanger (12) or of the evaporative cooler (13) is regulated, wherein one or all of the following variables are included in the regulation: level of water in the reservoir, use of a retarder, air conditioning, state of charge and temperature of the battery, driving speed, total weight, terrain topology, and traffic situation.

18. A use of a fuel cell device (1) according to the preceding claims in a motor vehicle, wherein the fuel cell device (1) is integrated or retrofitted in the motor vehicle.

Description

[0053] The following is shown:

[0054] FIGS. 1 to 7 each schematically show a simplified diagram of a preferred exemplary embodiment of a fuel cell device.

[0055] FIGS. 1 to 7 show preferred exemplary embodiments of a fuel cell device denoted overall by the reference numeral 1. They can all be integrated or retrofitted into a motor vehicle.

[0056] FIG. 1 shows a simplified diagram of a preferred exemplary embodiment of a fuel cell device 1. The fuel cell device 1 has a fuel cell 2, which is indicated by a small box. A supply air path 3 for a cathode supply air flow 5, which defines a supply air flow direction 4, leads to the fuel cell 2, the cathode supply air coming from supply air which is supplied to the fuel cell 2 and contains water. The fuel cell device 1 also has an exhaust air path 7 leading away from the fuel cell 2, for a cathode exhaust air flow 9, which defines an exhaust air flow direction 8, the cathode exhaust air coming from water-containing exhaust air flowing from the fuel cell 2. Depending on the operation, the exhaust air flowing out of the fuel cell is under an absolute pressure of, for example, 0.8 to 1.5 bar or 1.8 bar to 2.5 bar or 1.5 bar to 3.0 bar. The supply air path 3 and the exhaust air path 7 are each routed through a humidifier 10 of the fuel cell device 1, which humidifier communicates fluidically with the supply air and the exhaust air and is also indicated by a small box and used for humidifying the supply air and dehumidifying the exhaust air. The exhaust air path 7 is also routed through a multi-part water separator 11 of the fuel cell device 1, which water separator communicates fluidically with the exhaust air, for removing water from the exhaust air and for providing this water as evaporation water. One part of the multi-part water separator 11, which is arranged upstream of the humidifier 10 with respect to the cathode exhaust air flow 9, is formed by a coarse water separator 14 for removing water from the exhaust air and for providing this water as evaporation water. The coarse water separator 14 can remove relatively large water droplets from the exhaust air, as a result of which a relatively large water quantity or a relatively large water volume can advantageously be obtained and made available. The other part of the multi-part water separator 11, which is arranged downstream of the humidifier 10, is formed, for example, by a fine water separator 15 for removing water from the exhaust air flowing out of the humidifier 10 and for providing this water as evaporation water. The fine water separator 15 can remove relatively small water particles and/or residual moisture from the exhaust air. As a result, it can advantageously remove at least a relatively small water quantity or a relatively small water volume from the exhaust air flowing out of the humidifier 10 and provide it as evaporation water. The fine water separator 15 offers the further advantage that the exhaust air is dehumidified in such a way that components of the fuel cell device 1 arranged further downstream in the cathode exhaust air flow 9, in particular a compressor system 34 to be explained below, are protected from moisture damage, in particular droplet impact. In the present case, the fine water separator 15 is equipped with a water outlet 39, which allows collected waste water/evaporation water to be discharged into the environment 6 of the fuel cell device 1, which is indicated purely symbolically in FIG. 1 by an arrow.

[0057] FIG. 1 also shows a heat exchanger 12, which is used to cool the fuel cell 2 and has an evaporative cooler 13, which is provided for cooling the heat exchanger 12. The evaporative cooler 13, for example, is assigned to the coarse water separator 14 in fluidic communication and supplied with evaporation water by same. The evaporation water flows, for example, through an evaporation water line 19 fluidically connecting the evaporative cooler 13 to the coarse water separator 14, with a feed water path 16 for a feed water flow 18 of evaporation water, which feed water flow defines a feed flow direction 17, leading through the evaporation water line. According to the invention, it is thereby possible for removing water from the cathode exhaust air flow 9 by means of the coarse water separator 14 during operation of the fuel cell device 1 and to use it as evaporation water for the evaporative cooler 13. Expediently, during operation of the fuel cell device 1, a sufficient water quantity or a sufficient water volume can be provided as evaporation water at the coarse water separator 14, so that the evaporative cooler 13 can be optimally supplied, whereby it can generate a predetermined or predeterminable cooling capacity. This has the advantage that external evaporation water sources can be dispensed with, which simplifies the fuel cell device 1.

[0058] FIG. 2 shows a simplified diagram of a preferred, further exemplary embodiment of a fuel cell device 1. It differs from the previous exemplary embodiment in particular due to a compressor system labeled with the reference numeral 34 and a valve device 23. The compressor system 34, for example, has a compressor 35, which has a drive turbine 38 that is or can be operated with exhaust air and an impeller 36 for compressing supply air. The impeller 36 allows supply air to flow through it and is inserted into the cathode supply air flow 5 upstream of the fuel cell 2 and the humidifier 10 in relation to the supply air flow direction 4. An air filter 40 of the compressor system 34 is arranged upstream of the impeller 36 in the supply air flow direction 4 to filter the supply air flowing into the impeller 36, and a charge air cooler 41 of the compressor system 34 is arranged downstream of the impeller 36 for cooling compressed supply air. The drive turbine 38 of the compressor 35 allows exhaust air to flow through and is inserted into the cathode exhaust air flow 9, in the exhaust air flow direction 8, downstream of the fine water separator 15. This drive turbine transmits kinetic energy from the exhaust air to the impeller 36, which then transmits it to the supply air. The aforementioned valve device 23 is used to control or regulate a mass or volumetric flow of the feed water flow 18 of evaporation water, which feed water flow flows through the evaporation water line 19. The valve device is implemented, for example, by a water feed valve 25 or a float valve 26 and allows evaporation water to flow through and is fluidically inserted into the feed water flow 18, between the evaporative cooler 13 and the coarse water separator 14, so that the mass or volumetric flow of evaporation water flowing into the evaporative cooler 13 can be conveniently controlled or regulated.

[0059] FIG. 3 shows a simplified diagram of a preferred, further exemplary embodiment of a fuel cell device 1. It differs from the previous exemplary embodiments in particular in that the fine water separator 15 is connected to the water outlet 39, in fluidic communication, via a water outlet valve 33a, so that the discharge of waste water/evaporation water from the fine water separator 15 to the environment 6 of the fuel cell device 1 can be controlled or regulated. Furthermore, FIG. 3 shows a collection volume, denoted by the reference numeral 27, for collecting evaporation water. The collection volume 27 is fluidically connected to the evaporative cooler 13 on one side and to the coarse water separator 14 on the other, so that evaporation water can flow from the coarse water separator 14 to the evaporative cooler 13. In the present case, the collection volume 27 is formed or delimited both by the evaporation water line 19 for the feed water flow 18 of evaporation water and by a separate evaporation water tank 28, which is fluidically inserted into the feed water flow 18. The evaporation water tank 28 in this case allows evaporation water to flow through and is fluidically arranged between the valve device 23 and the evaporative cooler 13. By way of example, it is provided that a feed valve device 31 is connected downstream of the evaporation water tank 28 with respect to the feed flow direction 17 and communicates fluidically with the evaporation water tank 28 and the evaporative cooler 13. It is used to control or regulate a mass or volumetric flow of the feed water flow 18 of evaporation water flowing out of the evaporation water tank 28 in the direction of the evaporative cooler 13. The feed valve device 31 in this case allows evaporation water to flow through and is fluidically inserted into the feed water flow 18, between the evaporative cooler 13 and the evaporation water tank 28. By way of example, the feed valve device 31 is implemented by a sprinkler valve 42 which controls or regulates the supply of evaporation water into the evaporative cooler 13 in terms of volume or quantity. The evaporation water tank 28, for example, has a tank collection volume 29 of greater than 0 liters/kW and less than or equal to 0.1 liters/kW of installed electrical output of the fuel cell 2.

[0060] FIG. 4 shows a simplified diagram of a preferred, further exemplary embodiment of a fuel cell device 1. It differs from the previous exemplary embodiment in particular in that the feed valve device 31 is now in several parts and has a conveying device 32 for conveying evaporation water from the evaporation water tank 28 to the evaporative cooler 13 and a further water outlet valve 33 for discharging evaporation water from the evaporation water tank 28. The conveying device 32 is implemented, for example, by a delivery pump, particularly a peripheral wheel pump or a side channel impeller. The water outlet valve 33 is arranged fluidically indirectly on the evaporation water tank 28 via the conveying device 32.

[0061] FIG. 5 shows a simplified diagram of a preferred, further exemplary embodiment of a fuel cell device 1. It differs from the previous exemplary embodiment in particular in that the further water outlet valve 33 of the feed valve device 31 for discharging evaporation water from the evaporation water tank 28 is now arranged directly on the evaporation water tank 28 and not via the conveying device 32 and in that the conveying device 32 of the feed valve device 31 is now implemented by a sprinkler valve 42.

[0062] Furthermore, it is provided according to this exemplary embodiment that the evaporation water tank 28 is pressurized by means of pressurized supply air from the cathode air system, for example from the cathode supply air flow 5. For this purpose, a compressed air line 43 is provided, which opens into the supply air path 3 at one end and into the evaporation water tank 28 at the other end. An air valve 30, which allows air from the cathode supply air flow 5 to flow through, is also inserted into the compressed air line 43, which air valve allows the air flow flowing through the compressed air line 43 to be controlled or regulated, so that the air pressurization of the evaporation water tank 28 can be controlled.

[0063] FIG. 6 shows a simplified diagram of a preferred, further exemplary embodiment of a fuel cell device 1. It differs from the previous exemplary embodiment in particular in that evaporation water is provided not only by the coarse water separator 14 on the evaporation water tank 28, but also by the fine water separator 15. As an example of this, a further feed water path 20 for a further feed water flow 22 of evaporation water, which further feed water flow defines a further feed flow direction 21, is provided, which feed water flow leads from the fine water separator 15 to the evaporation water tank 28 via a water feed valve 33a. This means that the evaporation water tank 28 is connected to the coarse water separator 14 and the fine water separator 15 with fluidic communication, so that evaporation water from the exhaust air provided by the coarse water separator 14 and the fine water separator 15 can flow to the evaporation water tank 28 and, from there, can flow to the evaporative cooler 13 either via a sprinkler valve 42 or a conveying device 32, and/or can flow to the environment 6 of the fuel cell device 1 via a further water outlet valve 33. The feed water path 16 and the further feed water path 20 are each routed, for example, through an evaporation water line 19, which fluidically connects the coarse water separator 14 or the fine water separator 15 to the evaporation water tank 28.

[0064] FIG. 7 shows another simplified diagram of a preferred, further exemplary embodiment of a fuel cell device 1. It differs from the exemplary embodiment of FIG. 6 only due to an added extraction point for water at or downstream of the drive turbine 38. The water accumulating at the extraction point can be supplied to the evaporation water tank 28 via a valve, which is illustrated by a small box and labeled with reference numeral 44 in FIG. 7. It is provided, for example, that said evaporation water tank 28 is fluidically connected to the drive turbine 38 via the valve 44. As a result, water can flow from the exhaust air flow 9 of the fuel cell 2 into the evaporation water tank 28 via the valve 44. Particularly when waste heat from the fuel cell 2 is used, a relatively large water quantity can accumulate in or on the drive turbine 38, but this has little or no overpressure with respect to the standard atmosphere. It is particularly advantageous to arrange the evaporation water tank 28 below the drive turbine 38 so that the water obtained can flow into the evaporation water tank 28. Alternatively or additionally, a pump (not shown) can also be used to convey the water into the evaporation water tank 28.

[0065] In all of the exemplary embodiments, the evaporation water tank 28 can also be referred to as a water tank 28, or vice versa. In all of the exemplary embodiments, evaporation water can also be referred to as cooling water, or vice versa.