Gas supply device for fuel cell and fuel cell system

Abstract

The invention relates to a gas supply device (20) having a suction line (18) for gas to be sucked and a pressure line (22) for conveying sucked gas to a consumer (24), a compressor wheel (26) being rotatably mounted between the suction line (18) and the pressure line (22) by means of a shaft (28), the shaft being mounted by means of a bearing (13), a drive unit (12) for driving the compressor wheel (26) by means of the bearing (13), in particular an electric motor drive unit, which is provided for a drive shaft (28), in which a gas supply device (20) is formed with a chamber (16) that can be supplied with gas, a gas path (30) is branched from a pressure side (40) of the compressor wheel such that the branched gas can be used at least indirectly for supplying gas to the chamber (16), the gas path comprising a discharge line (33) downstream, thus, a fluid connection of the gas path (30) to the turbine (34, 41) is provided.

Description

Technical Field

[0001] The invention relates to a gas supply device and a corresponding fuel cell system. Background Art

[0002] For example, Chinese patent application CN218439809U discloses a gas supply device which provides cooling for the drive unit. However, in these gas supply devices, the gas introduced back to the suction side reduces the conveying performance of the gas supply device due to its relatively high temperature. Summary of the invention

[0003] In contrast, the gas supply device according to the invention has the advantage of improved conveying performance. Here, a gas path is advantageously branched off from the pressure side of the compressor impeller, so that the branched gas can at least indirectly contribute to the supply of gas to the chamber to be cooled of the gas supply device or to the component to be cooled of the gas supply device, wherein the gas path includes a discharge line downstream, thereby providing a fluid connection of the gas path to the turbine. As a result, it is possible to avoid the laborious return of the branched gas to the suction area of ​​the gas supply device. It is therefore also possible to provide cooling in the chamber while retaining the good conveying performance of the gas supply device, in particular to provide cooling for the inner area of ​​the gas supply device, in which the drive unit or the bearing is arranged.

[0004] Advantageous developments and improvements of the gas supply device according to the invention can be achieved by means of the measures listed in the preferred embodiments.

[0005] It is particularly advantageous if, in particular, the cold air sucked in for the chamber is purified by means of an air filter before it reaches the chamber in order to protect the air from harmful environmental influences.

[0006] Furthermore, it is advantageous if the branched-off gas is discharged either into a turbine volute of a turbine wheel which is driven by the exhaust gas of a consumer or into the associated turbine output.

[0007] It is also advantageous to use the branched-off gas for a Venturi device which allows cold air to be drawn in from the surroundings.

[0008] It is also advantageous to feed hot Venturi nozzle air, i.e. hot air discharged from the chamber to be cooled, together with the branched-off gas into the turbine volute or into the turbine outlet so that it can enter the surroundings of the gas supply device via the turbine volute or via the turbine outlet. In this case, the hot air heats the exhaust air of the consumer, for example the exhaust gas of a fuel cell stack, thereby reducing the risk of exhaust gas condensation in the area of ​​the gas supply device or droplet impacts in the area of ​​the turbine wheel. danger. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description.

[0010] Figure 1 The gas supply arrangement is shown. DETAILED DESCRIPTION

[0011] exist Figure 1 , a gas supply device 20 is shown, which can suck gas during operation via the suction line 18 or via a related suction line attachment not shown in detail and deliver the sucked gas to a consumer 24 of the gas via the pressure line 22 or via a related pressure line attachment not shown in detail. Here, a compressor impeller 26 is arranged between the suction line and the pressure line, wherein the side of the compressor impeller 26 facing the suction line forms a suction area 38, from which gas or air is sucked or compressed. Here, the compressor impeller 26 is firmly connected to a shaft 28, the rotational movement of which also puts the compressor impeller into rotational movement. The shaft is supported by two bearings 13, and a drive unit 12, in particular an electric motor drive unit, is provided for driving the shaft 28. In the case of a configuration as an electric motor drive unit, the drive unit forms an electrically controllable stator, which can put the shaft, which is configured as a rotor in this case, into rotational movement by means of magnetic forces.

[0012] The drive unit and the two bearings are arranged in a chamber 16 which can be supplied with air via an opening 36 .

[0013] In order to draw in the cooling air 11 for cooling the drive unit or the bearings, a Venturi device 10 is provided. It draws air from the chamber 16 on the side of the chamber 16 opposite the opening 36, so that fresh cooling air 11 can flow on via the opening 36 and cool the drive unit 12, in particular the stator, or the bearings 13 via the cooling air path 17. The Venturi device generates the negative pressure required for this in its constriction region by means of the gas flowing through it, which branches off from the pressure side 40 of the compressor wheel 26 of the gas supply device 20 via the gas path 30 and is supplied to one end of the Venturi device 10. Thus, in this case, the gas compressed by the gas supply device (which is actually intended for the consumer 24) is partially branched off inside the gas supply device, so that the gas can be used indirectly to supply the chamber 16 by providing a negative pressure, which can be used to draw in cooling air from the surroundings by means of the Venturi device.

[0014] The described suction of maximum cold air 11, in particular maximum cold air from the surrounding environment, is used to optimize the performance of the electric air compressor or the gas supply device. Therefore, the cold air is distributed in the internal chamber 16 of the compressor via different air paths 17, supplied to the areas and components to be cooled, and then discharged. Here, the branched gas is guided to the turbine output end 37 of the turbine volute 41, i.e., to the exhaust path of the turbine, together with the gas sucked from the chamber 16 via the discharge line 33 attached to the other end of the venturi device 10. Here, the gas supply device 20 is a single-stage air compression device, in which the compressor impeller 26 is arranged at one end of the shaft 28, and the turbine impeller 34 is arranged at the other end, wherein the turbine impeller is configured to drive the shaft with the help of gas or exhaust gas led back from the consumer 24. For this purpose, the turbine wheel is arranged in a turbine volute 41 , wherein the recirculated exhaust gas is supplied (to the turbine wheel) via the turbine input 35 of the turbine volute 41 and discharged downstream of the turbine wheel 34 via the turbine output 37 of the turbine volute 41 to the surroundings of the gas supply device.

[0015] The drive via the turbine wheel supplements the drive via the electric motor drive unit, so that by suitable activation of the electric motor drive unit or by suitable switchable gas routing one drive type or the other or both drive types can be used selectively or in parallel.

[0016] As an alternative or in addition to discharging the branched-off gas directly to the turbine output, the branched-off gas can also be discharged by introducing it into the turbine volute 41, so that the branched-off gas can be mixed with the gas sucked from the chamber 16 and the exhaust gas led back from the consumer in the area of ​​the turbine volute 41. This can be established by a direct connection of the discharge line 33 to the turbine volute 41, which is not shown in detail, via an input end to the turbine volute that is provided separately for the discharge line.

[0017] An air filter 15 is arranged in the cold air intake line 14 or in the cold air intake connection before (upstream of) the opening 36 of the gas supply device 20, so that the gas or cold air 11 flowing into the chamber 16 is purified before reaching the chamber 16. Alternatively, the air filter can also be arranged directly in the opening.

[0018] The consumer 24 supplied with gas or air compressed by the gas supply device can be in particular a fuel cell stack, which is supplied with air or oxygen on its cathode side in this way. Accordingly, the fuel cell system can have at least one fuel cell stack and at least one such gas supply device in order to supply air or oxygen to the cathode side of the fuel cells of the fuel cell stack. In this case, the gas not consumed by the fuel cell stack or the exhaust gas of the fuel cell stack is fed back to the gas supply device in order to drive the turbine wheel 34 of the gas supply device and thereby at least contribute to the compression or suction of the required gas by the gas supply device.

Claims

1. A gas supply device (20) having a suction line (18) for gas to be sucked and a pressure line (22) for conveying the sucked gas to a consumer (24), wherein: A compressor impeller (26) is arranged between the suction line (18) and the pressure line (22) in a rotatably supported manner via a shaft (28), wherein the shaft is supported via at least one bearing (13), and wherein a drive unit (12), in particular an electric motor drive unit, is provided for driving the shaft (28), wherein at least one chamber (16) which can be supplied with gas is constructed in the gas supply device (20), wherein a gas path (30) branches off from the pressure side (40) of the compressor impeller so that the branched gas can be used at least indirectly to supply the chamber (16), characterized in that the gas path comprises a discharge line (33) downstream, thereby providing a fluid connection between the gas path (30) and the turbine (34, 41).

2. The gas supply device according to claim 1, characterized in that: The gas supply device forms a single-stage air compression device.

3. The gas supply device according to claim 1 or 2, characterized in that: The compressor impeller (26) is arranged at one end of the shaft (28), and the turbine impeller (34) of the turbine (34, 41) is arranged at the other end of the shaft, wherein the turbine impeller is arranged in a turbine volute (41) of the turbine and is configured to drive the shaft with the aid of exhaust gas directed back from the consumer (24), wherein the directed back exhaust gas can be supplied via a turbine input (35) of the turbine volute (41) and can be discharged downstream of the turbine impeller (34) via a turbine output (37) of the turbine volute (41) to the environment of the gas supply device.

4. The gas supply device according to claim 3, characterized in that: The exhaust line (33) is connected to the turbine output (37).

5. The gas supply device according to claim 3, characterized in that: The exhaust line (33) is connected to the turbine volute (41) in such a way that the branched-off gas can be mixed with the recirculated exhaust gas in the region of the turbine volute (41).

6. A gas supply device according to any one of the preceding claims, characterised in that The drive unit and / or the at least one bearing are arranged in the chamber (16) which can be supplied with air.

7. A gas supply device according to any one of the preceding claims, characterised in that The gas path (30) has a venturi device (10) which is arranged to draw in gas located in the chamber (16) to which gas can be supplied.

8. The gas supply device according to claim 7, characterized in that: The discharge line (33) is arranged downstream of the Venturi device (10).

9. A gas supply device according to any one of the preceding claims, characterised in that The chamber (16) has an opening (36) through which gas, in particular air from the surroundings, can flow into the chamber (16).

10. The gas supply device according to claim 9, characterized in that: A filter (15) for purifying the gas flowing into the chamber is arranged before or in the opening (36).

11. A gas supply device according to any one of the preceding claims, characterised in that The shaft (28) is designed as a rotor and the drive unit (12) is designed as a stator for electromagnetically driving the rotor.

12. A gas supply device according to any one of the preceding claims, characterised in that The consumer (24) is a fuel cell stack. 13 . A fuel cell system having at least one fuel cell stack and at least one gas supply device according to claim 1 for supplying the cathode side of the fuel cell with air or oxygen.

14. The fuel cell system according to claim 13, characterized in that: Unconsumed gas and / or exhaust gas of the fuel cell stack is fed back to the gas supply device in order to drive a turbine (34, 41) of the gas supply device (20).

Images