Blower for a fuel cell array

Abstract

A blower (1) for a fuel cell assembly for recirculating a gas mixture used for operating the fuel cell assembly is equipped with a drive motor (7, 8, 9) comprising a rotor (9) coupled to a motor shaft (7) and a stator (8) arranged radially outside the rotor (9). An annular channel (10) is provided radially between the rotor (9) and the stator (8) for conveying the gas mixture from an inlet side to an outlet side of the annular channel (10). A blower impeller (5) coupled to the motor shaft (7) is provided in the region of the outlet side of the annular channel (10) to convey the gas mixture from the inlet side to the outlet side of the annular channel (10) when rotating. Furthermore, a flow guide device (14) is provided to impart a circumferential swirl to the gas mixture entering the annular channel (10).The annular channel (10) is bounded by an assembly consisting of an outer wall (16; 21) and an inner wall (17), wherein the flow guide device (14) is provided on the inlet side between the outer wall (16; 21) and the inner wall (17).

Description

Technical area

[0001] The present invention relates to a blower for a fuel cell assembly for recirculating a gas mixture used to operate the fuel cell assembly. In particular, the present invention relates to a blower that enables the separation of water from the gas mixture. Furthermore, the invention relates to a fuel cell assembly with such a blower. State of the art

[0002] Fuel cells of various designs are used for stationary and mobile applications. In such known fuel cells, which use hydrogen as the energy carrier, there is a need to convey gaseous media. In particular, fuel cells with an anode region and a cathode region are known, with hydrogen being recirculated from the anode region to ensure the function of the fuel cell. For this purpose, fans designed to convey the corresponding gaseous medium are used in the prior art.

[0003] The object of the invention is to provide an improved and easily manufactured blower that can ensure the proper functioning of the fuel cell system. This object is achieved by the features of the claims. Description of the invention

[0004] According to one aspect, the present invention relates to a blower for a fuel cell assembly. The blower for a fuel cell assembly is provided for recirculating a gas mixture used to operate the fuel cell assembly. The blower has a drive motor that has a rotor coupled to a motor shaft and a stator arranged radially outside the rotor.

[0005] In this case, an annular channel is provided radially between the rotor and the stator for conveying the gas mixture from an inlet side to an outlet side of the annular channel, wherein in the region of the outlet side of the annular channel a fan impeller coupled to the motor shaft is provided in order to convey the gas mixture from the inlet side to the outlet side of the annular channel during rotation.

[0006] The blower further comprises a flow guiding device which is provided in the region of the inlet side of the annular channel and is designed to impart a swirl in the circumferential direction of the annular channel to the gas mixture entering the annular channel.

[0007] In the blower, the annular channel is defined by an assembly consisting of an outer wall and an inner wall, with the flow guide device being provided on the inlet side between the outer wall and the inner wall.

[0008] The blower can be used to recirculate a gas mixture associated with an anode region of the fuel cell assembly. The gas mixture can contain hydrogen. The gas mixture can also contain other components that can result, in particular, from the reaction of the hydrogen in the anode region of the fuel cell assembly. The gas mixture can contain water, which results from the reaction of the hydrogen. The gas mixture can be passed through the anode region of the fuel cell assembly.

[0009] The blower can be connected to one or more fuel cell modules via appropriate piping within the fuel cell arrangement such that the blower can direct the gas mixture through the anode region of the fuel cell arrangement. The blower can also be connected to a hydrogen source, via which the hydrogen content of the recirculated gas mixture can be adjusted. The blower can be operated by a drive motor, which can be configured as an electric motor. The electric motor can be a brushless motor. The drive motor can be a media gap motor. In this case, the medium conveyed by the blower, in particular the gas mixture used in the fuel cell arrangement, can be conveyed through the annular channel. The annular channel can have a cylindrical inner wall and a cylindrical outer wall.The gas mixture can flow from the inlet side to the outlet side between the cylindrical inner wall and the cylindrical outer wall of the annular channel. The cylindrical outer wall can be formed, at least in part, as an outer tube arranged radially inside the stator. The cylindrical inner wall can be formed, at least in part, by an outer circumference of the rotor. Alternatively, the cylindrical inner wall can be formed, at least in part, by an inner tube arranged radially outside the rotor.

[0010] The fan impeller coupled to the motor shaft can be arranged on the outlet side of the annular channel such that the gas mixture can be conveyed through the annular channel upon rotation of the fan impeller. The fan impeller can have an arrangement of blades distributed around the circumference of the fan impeller. By rotating the fan impeller, the gas mixture can be conveyed based on a corresponding pumping function. Due to its rotation, the fan impeller can convey the gas mixture in a radial direction relative to the annular channel.

[0011] The flow guide device can be provided in the region of the inlet side of the annular channel and configured such that a swirl in the circumferential direction of the annular channel is generated on the gas mixture entering the annular channel, which swirl moves the gas mixture around the inner wall of the annular channel. In particular, the flow guide device can be configured such that the gas mixture is moved through the annular channel along streamlines that have a circumferential velocity component. Due to the superposition of the circumferential velocity component with an axial velocity component, the gas mixture can be conveyed in a helical shape around the inner wall of the annular channel. In this respect, the flow guide device is designed such that a swirl can be generated to form helical streamlines of the gas mixture around the longitudinal axis of the annular channel.Due to the swirl imposed on the conveyed gas mixture by the flow guide device, a centrifugal force is imposed on the components of the gas mixture, which causes components with a higher density of the gas mixture to move radially outwards within the annular channel.

[0012] According to one embodiment, the flow guiding device may comprise a flow-through arrangement of guide vanes extending between the outer wall and the inner wall.

[0013] According to one embodiment, the flow guide device can be formed integrally with at least one of the outer wall and the inner wall. For this purpose, the elements of the flow guide device can be manufactured together with tubular elements that delimit the annular channel at least in sections. The elements of the annular channel can comprise guide vanes.

[0014] According to one embodiment, the outer wall or the inner wall can be connected to form a single assembly via the flow-guiding device. Alternatively, the outer wall and the inner wall can be connected to form a single assembly via the flow-guiding device.

[0015] According to one embodiment, a flow insert can be provided on the upstream side of the flow guide device, which is configured to guide a flow directed toward the flow insert via the flow guide device into the annular channel. The flow insert can be manufactured integrally with the tubular elements delimiting the annular channel. Alternatively or additionally, the flow insert can be manufactured integrally with the elements of the flow guide device.

[0016] According to one embodiment, the flow installation can in particular be formed integrally at least with the outer wall.

[0017] According to one embodiment, the outer wall and the inner wall can be manufactured as a single part via the flow guide device to form an assembly. An injection molding process can be used for this purpose. Alternatively, at least a portion of the assembly can be manufactured using an additive manufacturing process.

[0018] According to one embodiment, the assembly manufactured as a single part may include the flow insert. In this case, the elements defining the annular channel, the guide vanes, and the flow insert are manufactured together.

[0019] According to one embodiment, the assembly may be made of plastic. The assembly may be made of aluminum.

[0020] According to one embodiment, the assembly can be manufactured using an additive manufacturing process. Individual sections of the assembly can be additively manufactured, and additional manufacturing processes can be used.

[0021] According to one embodiment, a bearing seat for a bearing supporting the motor shaft can be provided on the radially inner side of the inner wall. In this case, the bearing can be supported relative to the inner tube defining the annular channel and thus relative to the fan housing.

[0022] According to one embodiment, a bearing seat for a bearing for supporting the motor shaft can be formed on an inner circumference of the flow assembly. In this case, the bearing can be supported relative to the fan housing above the flow guide device.

[0023] According to one embodiment, the bearing seat can be made of a metal material and molded onto the material of the inner wall. For this purpose, a ring can be attached to the inner wall material as a bearing seat. The bearing seat can be integrated during the manufacture of the inner tube or the flow assembly.

[0024] According to one embodiment, in the region of the outlet side of the annular channel, a water drainage arrangement can open into it, which is designed to drain water moving along the wall of the widened portion to a water outlet arrangement. The water drainage arrangement can be designed as an annular channel at the outlet end, which can be connected to a line for draining the water entering the annular channel. The water drainage arrangement can be designed as at least one opening in or on the outlet side of the annular channel, into which the water can enter. The water outlet arrangement can have a container for receiving the water drained from the water drainage arrangement. The water outlet arrangement can further have a line by means of which the water drained by the water drainage arrangement can be drained away, in particular into the environment.

[0025] According to a further aspect, a fuel cell arrangement is specified with a blower that has one or more of the aforementioned features, wherein the blower is connected to the fuel cell arrangement for recirculating a gas mixture used for operating the fuel cell arrangement. The blower can be connected to a fuel cell module via a line arrangement in the fuel cell arrangement. The blower can be provided for recirculating hydrogen-containing gas for the fuel cell arrangement. In particular, the recirculation of the hydrogen-containing gas can be designed for the anode side of the fuel cell arrangement. The blower can be controlled, if required, via a control device, wherein an operating state of the fuel cell arrangement can be taken into account.The fuel cell arrangement may also comprise a plurality of fans of the type described above, which are integrated into the fuel cell arrangement by means of lines.

[0026] The blower and the fuel cell assembly can be used in a mobile application. In particular, the blower and the fuel cell assembly can be used in an electrically powered vehicle, wherein the electrical power can be generated by the fuel cell assembly. Alternatively, the fuel cell assembly with the blower can be used in a stationary application. Alternatively, the blower can be used to provide a gas flow in other areas. In particular, the blower can be used to achieve a flow through the cathode side of the fuel cell assembly. Short description of the characters Fig. 1 shows an embodiment of a blower in a cross-sectional view; and Fig. 2 shows a modified embodiment of a blower in a cross-sectional view. Detailed description of embodiments

[0027] Embodiments are described below with reference to the accompanying drawings.

[0028] Fig. Figure 1 shows a blower in one embodiment in a cross-sectional view. The basic structure of the blower is described below based on Fig. 1. As shown in the cross-sectional view of Fig. 1, the blower 1 has a main housing 2. The main housing 2 forms the outer circumference of a main section of the blower 1 and is cylindrical in the present embodiment. Arranged radially inside the main housing 2 is a drive motor which has a radially outer stator 8, a radially inner rotor 9 and a motor shaft 7 connected to the rotor 9. The stator 8 is connected to the main housing 2 in a rotationally fixed manner. The rotor 9 is connected to the rotatable motor shaft 7 so that the rotor 9 can rotate together with the motor shaft 7. The motor shaft 7 is rotatably mounted on both sides via bearings 11, 12. In the present embodiment, the rotor 9 is designed as a permanent magnet element. When energized, the stator 8 generates a rotating magnetic field so that the rotor 9 rotates together with the motor shaft 7 when energized.

[0029] On the left side in Fig. 1, the main housing 2 has an outlet housing 4. The outlet housing 4 has a passage in the center through which the motor shaft 7 passes. In the area of ​​the outlet housing 4, a fan impeller 5 is connected to the motor shaft 7. Rotation of the motor shaft 7 causes rotation of the fan impeller 5. The outlet housing 4 has an outlet volute radially outside the outlet housing 4, which has a circumferentially variable diameter and is open towards the fan impeller 5. A housing flange 6 is attached to the outlet housing 4, which has a passage in the center into which the motor shaft 7 projects.

[0030] The fan impeller 5 has blades that are designed with a predetermined shape to achieve the pumping function. The inside of the housing flange 6 and the inside of the outlet housing 4 are adapted to the contour of the fan impeller 5 in the radial region where the fan impeller 5 is provided. Radially outside the fan impeller 5 is an annular gap that is open to the volute within the outlet housing 4. On the side of the fan impeller 5 facing away from the rotor 9, the bearing 11 for supporting the motor shaft 7 is provided. In the present embodiment, the bearing 11 comprises a set of rolling bearings, the outer ring of which is inserted into the housing flange and the inner ring of which is mounted on the motor shaft 7. The housing flange 6 has a cover (not explained in detail) on the side of the bearing 11 facing away from the rotor.

[0031] An annular channel 10 is provided radially between the stator 8 and the rotor 9. A radial inner wall 17 of the annular channel 10 is formed by an outer circumference 20 of the rotor 9 and by an outer circumference of a flow insert 15. In an alternative embodiment, the radial inner wall is formed by an inner tube surrounding the rotor 9 and by the outer circumference of the flow insert 15. On the side of the guide vane 14 facing away from the rotor 9, the flow insert 15 is provided in the form of an axisymmetric flow body. The flow insert 15 has a dome or spherical cap shape. The outer diameter of the flow insert 15 is smaller than the diameter of the outer tube of the annular channel 10. The flow insert 15 projects axially into a region of the inlet housing 3 in which a constriction is provided. The flow installation 15 has a flow-optimized outer contour with respect to the flow from the inlet housing 3.The flow installation 15 has an outer circumferential surface which serves as the inner wall 17 of the annular channel 10, at least at the inlet area.

[0032] The outer tube has a radial outer wall 16 and a diameter that is larger than the diameter of the rotor 9. The stator 8 is located radially outside the outer tube. This forms the annular channel 10, through which a fluid can flow. The annular channel 10 opens on the left side into Fig. 1 in the area of ​​the fan impeller 5. On the right side of the annular channel 10 there is a flow guide device described below.

[0033] On the right side in Fig. 1, the blower 1 has an inlet housing 3. The inlet housing 3 is cylindrical and a portion of it is inserted into the main housing 2. A sealing element is provided between the inlet housing 3 and the main housing 2. The inlet housing 3 is screwed to the main housing 2 via a mounting flange. The inlet flange 13 serves to connect to a pipe of the fuel cell assembly.

[0034] The flow control device is explained below. As in Fig. 1, the flow guide device is in the form of a guide grid 14 on the in Fig. 1 right-hand section of the annular channel 10. The guide vanes 14 have an arrangement of guide vanes distributed around a circumference of the flow guide device. The guide vanes are provided in particular in the area that forms an inlet area of ​​the annular channel 10. The guide vanes 14 can be flowed through through a passage in the inlet housing 3 in the direction of the annular channel 10.

[0035] In the present embodiment, the guide vanes 14 are integrated with the elements of the annular channel 10. In particular, the radial outer wall 16 in the inlet region of the annular channel 10 has the guide vanes of the guide vanes 14. The guide vanes are formed integrally with the outer tube of the annular channel 10. This design enables simplified production of the annular channel 10, since the outer tube can be manufactured as a single part with the guide vanes of the guide vanes 14. The component composed of the outer tube and guide vanes is manufactured from plastic using an injection molding process. In a modified embodiment, the component composed of the inner tube and guide vanes is manufactured using an additive manufacturing process, in particular using a 3D printing process.

[0036] Another embodiment is in Fig. 2. As can be seen, the motor shaft 7 extends radially into the space between the guide vanes of the guide vane 14 and is supported on the radially inner side of the flow insert 15. The outer circumference of the bearing 12 is supported on the axial region of the flow insert 15 where the guide vane 14 is provided. For this purpose, in the present embodiment, a bearing seat 18 is integrated into the flow insert 15. The bearing seat 18 is designed as a ring made of metal that is integrated into the material of the flow insert 15. For this purpose, the bearing seat 18 can be injection-molded or over-molded during the manufacturing process of the component. In the region where the guide vane 14 is provided, the motor shaft 7 is supported relative to the main housing 2 via the bearing seat 18, the flow insert 15, the guide vane 14 and an outer flange 21.

[0037] The flow installation 15 is in the embodiment of Fig. 2 is formed as a one-piece component with the guide vanes and the outer flange 21. This one-piece component consisting of the flow insert 15, guide vanes, and outer flange 21 is attached to the end section of the annular channel 10 during assembly. In an alternative embodiment, the flow insert is manufactured in one piece with the component consisting of the outer tube, inner tube, and guide vanes, so that the outer flange 21 is formed in one piece with the outer tube.

[0038] In an alternative embodiment, the component consisting of the outer tube, inner tube, and guide vanes, as well as optionally the flow insert 15, is made of a metal material, such as an aluminum alloy. In this case, the separate bearing seat 18 can be omitted.

[0039] With the structure described above, a flow through the fan 1 from the inlet side, which is on the right side in Fig. 1, to the exit side, which is on the left side in the Fig. 1 is possible. In particular, the flow into the inlet housing 3 runs through a widening annular gap between the flow insert 15 and the inner wall of the inlet housing 3, through the guide vane 14, into the annular channel 10 to the fan impeller 5, wherein the gas mixture is driven into the outlet volute in the outlet housing 4 by the rotation of the fan impeller 5.

[0040] The concept of the blower 1 shown is explained in more detail below.

[0041] The arrangement of vanes or blades in the guide vane 14 causes the gas mixture flowing through the guide vane 14 to be deflected in a circumferential direction as it flows through. For this purpose, the guide vane 14 has vanes or blades that are inclined and profiled with respect to the longitudinal axis of the annular channel 10. This causes a gas mixture entering the guide vane 14 essentially in a straight line to exit the guide vane 14 with a velocity component in the circumferential direction. This effect is achieved when the fan impeller 5 is operated, so that the gas mixture is conveyed by the fan 1. In addition, this effect also occurs when the gas mixture is conveyed through the fan 1, and in particular through the guide vane 14 and the annular channel 10, without rotation of the fan impeller 5.

[0042] Particularly in mobile applications, such as vehicle propulsion systems, icing of elements of the fuel cell assembly, and in particular of the blower 1 for recirculating the gas mixture, must be avoided. By efficiently removing the water from the blower 1, such ice formation can be easily prevented, for example, when the vehicle is parked for an extended period at low temperatures.

[0043] Due to the rotation of the gas mixture flow within the annular channel 10, an outward centrifugal force is exerted on the components of the gas mixture. If liquid water droplets are present in the gas mixture, the swirl or rotation of the gas mixture flow causes the liquid water droplets to move radially outward, so that they reach the inside of the radially outer wall of the annular channel 10. Due to the axial component of the gas mixture flow within the annular channel 10, the water droplets adhering to the inside of the outer wall of the annular channel 10 are moved axially toward the outlet side.

[0044] The blower can have a water drainage arrangement 19 provided on the outlet side of the annular channel and not described in more detail for draining water that moves on the inside of the outer tube due to the swirl of the flow in the annular channel 10. In one embodiment, the water drainage arrangement 19 is provided as an annular gap arranged in the outlet region of the annular channel 10. The water moving along the inside of the outer tube can thus enter the water drainage arrangement in the form of the annular gap. In the present embodiment, the annular gap of the water drainage arrangement 19 is connected to a water outlet arrangement via which the separated water can be accordingly drained away. In the present embodiment, the separated water is collected in a container (not shown).In an alternative embodiment, the water can be discharged into the environment, provided this is in accordance with environmental regulations.

[0045] It should be noted that the above-mentioned concepts, which were described separately on the basis of the figures, can be combined with each other.

[0046] The blower 1 of the present embodiments is used in a fuel cell assembly in which hydrogen-containing gas is circulated and reacts electrochemically to generate electrical energy. In particular, the blower 1 described here is used to purge an anode region of a fuel cell assembly to ensure a predetermined composition of the gas mixture present in the anode region.

[0047] Several of the above-described blowers 1 can be used in the fuel cell assembly. Furthermore, the fuel cell assembly generally comprises a control device that, among other things, controls the operation of the blower 1. This includes controlling a speed of the blower 1, with which the blower power can be adjusted. Furthermore, the operating state of the fuel cell assembly is used to determine whether or not operation of the blower 1 is required. In the event that the blower 1 is not operating, the gas mixture can easily be passed through the blower 1 due to the structure of the blower as a media gap motor.Due to the above-described structure of the blower 1 and in particular of the flow guide device with the guide grille 14, the separation function for separating water is brought about even when the blower 1 is not in operation by the flow through the blower 1, since the guide grille 14 imposes the swirl on the gas flow.

[0048] The blower described above is particularly applicable to the fuel cell arrangement described above. However, the blower is also applicable to other fuel cell arrangements, provided water separation is appropriate. Reference symbol 1 fan 2 main housings 3 inlet housing 4 Outlet housing 5 Fan impeller 6 Housing flange 7 Motor shaft 8 Stator 9 Rotor 10 ring canal 11 camps 12 camps 13 Inlet flange 14 guide vanes (flow control device) 15 Flow installation 16 Exterior wall 17 Interior wall 18 bearing seat 19 Water drainage arrangement 20 outer circumference rotor 21 Outer wall (outer flange)

Claims

[1] Blower (1) for a fuel cell arrangement for recirculating a gas mixture used for operating the fuel cell arrangement, comprising a drive motor (7, 8, 9) which has a rotor (9) coupled to a motor shaft (7) and a stator (8) arranged radially outside the rotor (9), wherein an annular channel (10) is provided radially between the rotor (9) and the stator (8) for conveying the gas mixture from an inlet side to an outlet side of the annular channel (10), wherein in the region of the outlet side of the annular channel (10) a blower impeller (5) coupled to the motor shaft (7) is provided in order to convey the gas mixture from the inlet side to the outlet side of the annular channel (10) during rotation, further comprising a flow guide device (14) which is provided in the region of the inlet side of the annular channel (10) and is designed to to impart a swirl in the circumferential direction of the annular channel (10) to the gas mixture,wherein the annular channel (10) is delimited by an assembly comprising an outer wall (16; 21) and an inner wall (17), wherein the flow guiding device (14) is provided on the inlet side between the outer wall (16; 21) and the inner wall (17). [2] Blower (1) according to claim 1, characterized by that the flow guiding device (14) has a flow-through arrangement of guide vanes which extend between the outer wall (16; 21) and the inner wall (17). [3] Blower (1) according to claim 1 or 2, characterized by that the flow guiding device (14) is formed integrally with at least one of the outer wall (16; 21) and the inner wall (17). [4] Blower (1) according to one of the preceding claims, characterized by that the outer wall (16; 21) and the inner wall (17) are connected to form an assembly via the flow guiding device (14). [5] Blower (1) according to one of the preceding claims, characterized bythat on the upstream side of the flow guiding device (14) a flow installation (15) is provided, which is designed to guide a flow directed towards the flow installation (15) via the flow guiding device (14) into the annular channel (10). [6] Blower (1) according to claim 5, characterized by that the flow installation (15) is formed integrally at least with the outer wall (21). [7] Blower (1) according to one of the preceding claims, characterized by that the outer wall (21) and the inner wall (17) are manufactured as one part to form an assembly via the flow guiding device (14). [8] Blower (1) according to claim 7, characterized by that the assembly manufactured as one part comprises the flow installation (15). [9] Blower (1) according to one of the preceding claims, characterized by that the assembly is made of plastic. [10] Blower (1) according to one of the preceding claims, characterized bythat the assembly is manufactured using an additive manufacturing process. [11] Blower (1) according to one of the preceding claims, characterized by that on the radially inner side of the inner wall (17) a bearing seat (18) for a bearing (12) for supporting the motor shaft (7) is provided. [12] Blower (1) according to claim 10, characterized by that the bearing seat is made of a metal material and is formed onto the material of the inner wall (17). [13] Fuel cell arrangement with a blower (1) according to one of the preceding claims, which is connected to the fuel cell arrangement for recirculating a gas mixture used for the operation of the fuel cell arrangement.

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