ANODE SUB-SYSTEM FOR A FUEL CELL SYSTEM, AND FUEL CELL SYSTEM

Abstract

The invention relates to an anode sub-system (1) for a fuel cell system with at least one fuel cell (2), comprising a supply path (3) for supplying the fuel cell (2) with hydrogen and comprising a recirculation path (4) for recirculating a gas mixture which exits the fuel cell (2) and contains water and hydrogen, wherein a water separator (5) is arranged in the recirculation path (4), and the recirculation path (4) is connected to the supply path (3) downstream of the water separator (5) via a jet pump (7). According to the invention, the supply path (3) is connected to the water separator (5) at the deepest point of the supply path via a connection line (9). The invention additionally relates to a fuel cell system comprising such an anode sub-system (1).

Claims

1. An anode sub-system (1) for a fuel cell system having at least one fuel cell (2), comprising a supply path (3) for supplying the at least one fuel cell (2) with hydrogen and a recirculation path (4) for recirculating a gas mixture which exits the at least one fuel cell (2) and contains water and hydrogen, wherein a water separator (5) is arranged in the recirculation path (4), and wherein the recirculation path (4) is connected to the supply path (3) downstream of the water separator (5) via a jet pump (7), wherein the supply path (3) is connected to the water separator (5) at the lowest point of the supply path via a connection line (9).

2. The anode sub-system (1) according to claim 1, wherein the water separator (5) for collecting separated water comprises a water tank (6) or is connected to a water tank (6).

3. The anode sub-system (1) according to claim 1, wherein the jet pump (7) has a first connection for the recirculation path (4) and a second connection for the supply path (3), and wherein the first connection is located above the second connection.

4. The anode sub-system (1) according to claim 3, wherein the jet pump (7) has a third connection for connecting to a hydrogen feed path (8).

5. The anode sub-system (1) according to claim 1, wherein, in the installed state of the anode sub-system (1), the water separator (5) is arranged at a lowest point so that water present in the supply path (3) and/or in the recirculation path (4) can be discharged via the water separator (5) due to gravity.

6. The anode sub-system (1) according to claim 1, wherein a throttle (10) is integrated into the connection line (9).

7. The anode sub-system (1) according to claim 1, wherein a valve (11) is integrated into the connection line (9).

8. The anode sub-system (1) according to claim 1, wherein a fan (13) is arranged in the recirculation path (4).

9. The anode sub-system (1) according to one claim 1, wherein the water separator (5), preferably the water tank (6) of the water separator (5), is connected to a gas line (14) with an integrated purge valve (15) and/or to a water line (16) with an integrated drain valve (17).

10. A fuel cell system having at least one fuel cell (2) and an anode sub-system (1) according to claim 1 for supplying hydrogen to the at least one fuel cell (2).

11. The anode sub-system (1) according to claim 4, wherein the hydrogen feed path (8) is arranged above the first connection for the recirculation path (4).

12. The anode sub-system (1) according to claim 7, wherein the valve (11) is a passive valve.

13. The anode sub-system (1) according to claim 8, wherein the valve (11) closes against a spring force of a spring (12) when the jet pump (7) is in a conveying mode.

14. The anode sub-system (1) according to claim 8, wherein the fan (13) is arranged between the water separator (5) and the jet pump (7).

15. The anode sub-system (1) according to claim 9, wherein the water tank (6) of the water separator (5) is connected to the gas line (14) with an integrated purge valve (15) and/or to the water line (16) with an integrated drain valve (17).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. The drawings show:

[0019] FIG. 1 a schematic section through a first anode sub-system according to the invention,

[0020] FIG. 2 a schematic section through a second anode sub-system according to the invention,

[0021] FIG. 3 an enlarged detail of FIG. 2,

[0022] FIG. 4 a schematic section through a third anode sub-system according to the invention during operation of a jet pump,

[0023] FIG. 5 an enlarged detail of FIG. 4,

[0024] FIG. 6 a schematic section through the anode sub-system of FIG. 4, but with the jet pump shut down, and

[0025] FIG. 7 an enlarged detail of FIG. 6.

DETAILED DESCRIPTION

[0026] The anode sub-system 1 according to the invention shown in FIG. 1 serves to supply at least one fuel cell 2 of a fuel cell system with hydrogen. For this purpose, it comprises a supply path 3, which is connected via a jet pump 7 to a hydrogen feed path 8 and to a recirculation path 4. The supply path 3 can thus be supplied with fresh hydrogen via the hydrogen feed path 8 and with hydrogen recirculated via the recirculation path 4. The volume of fresh hydrogen can be controlled via a hydrogen valve 18 integrated into the hydrogen feed path 8.

[0027] A water separator 5 comprising a water tank 6 is integrated into the recirculation path 4. The water tank 6 can be emptied via a water line 16, which is introduced from below, with an integrated drain valve 17. A nitrogen-containing gas mixture can be discharged from the recirculation path 4, or the recirculation path 4 can be flushed, via a gas line 14, which is introduced at the side of the water tank 6, with an integrated purge valve 15. This is necessary from time to time since nitrogen as well as liquid water escape from the fuel cell 2 with the hydrogen when the fuel cell system is in operation. The liquid water is separated via the water separator 5 and collected in the water tank 6; the nitrogen is removed via the flush volume.

[0028] A fan 13, by means of which the hydrogen leaving the fuel cell 2 can be optimally recirculated, is also integrated into the recirculation path 4.

[0029] Since, in principle, water can accumulate or precipitate at any point in the anode sub-system 1 so that undesirable water accumulation can form, the anode sub-system 1 shown in FIG. 1 comprises at its geodetically lowest point the water separator 5 with the water tank 6. The latter is connected to the supply path 3, specifically at the lowest point thereof, via a steadily rising connection line 9. It is thereby ensured that water accumulating or precipitating in the supply path 3 runs into the water tank 6 due to gravity even when the jet pump 7 is shut down. Undesirable accumulation of water is thus avoided.

[0030] FIGS. 2 and 3 show a development of the anode sub-system 1 of FIG. 1. In contrast to FIG. 1, a throttle 10 is integrated into the connection line 9. The throttle 10 leads to a controlled draining of water, which accumulates or precipitates in the jet pump 7 or in the supply path 3 downstream of the jet pump 7. In this way, parasitic currents are reduced, in particular during operation of the jet pump 7. As a result, the efficiency of the system is thus increased.

[0031] FIGS. 4 and 7 show a further embodiment of an anode sub-system 1 according to the invention. Instead of a throttle 10 according to the embodiment shown in FIGS. 2 and 3, a passive valve 11 is integrated into the connection line 9 here. Opening and closing of the valve 11 is pressure-controlled.

[0032] During operation of the jet pump 7 (FIGS. 4 and 5), the pressure in the supply path 3 increases so that a pressure gradient, which closes the valve 11 against the spring force of a spring 12, prevails between the supply path 3 and the recirculation path 4. Parasitic streams in the direction of the water separator 5 or the water tank 6 are thus completely prevented so that the efficiency of the system is increased further.

[0033] When the jet pump 7 is shut down (FIGS. 6 and 7), there is no pressure gradient keeping the valve 11 closed, so that the spring 12 opens the valve 11 and water present in the supply path 3 can flow out into the water tank 6 due to gravity.