Fuel cell system and vehicle with fuel cell system

Abstract

The technology disclosed herein relates to a fuel cell system (10) for a vehicle (100), comprising a fuel cell (11) with an anode (12) and a cathode (13), a cathode inlet path (14) for directing a cathode gas to the cathode (13), a cathode outlet path (15) for directing a cathode outlet fluid away from the cathode (13), a valve arrangement (20) for controlling a cathode gas flow in the cathode inlet path (14) and / or for controlling a cathode outlet fluid flow in the cathode outlet path (15), wherein the valve arrangement (20) comprises an inlet roller valve (21) for controlling the cathode gas flow in the cathode inlet path (14) and / or an outlet roller valve (31) for controlling the cathode outlet fluid flow in the cathode outlet path (15). exhibits. The technology also relates to a vehicle (100) with the fuel cell system (10).

Description

[0001] The technology disclosed herein relates to a fuel cell system for a vehicle, comprising a fuel cell with an anode and a cathode, a cathode inlet path for directing a cathode gas to the cathode, a cathode outlet path for directing a cathode outlet fluid away from the cathode, and a valve arrangement for controlling a cathode gas flow in the cathode inlet path and / or for controlling a cathode outlet fluid flow in the cathode outlet path. The technology further relates to a vehicle with such a fuel cell system.

[0002] Various fuel cell systems for mobile applications are known in the prior art. In a vehicle, fuel cell systems are typically configured to generate electricity for the vehicle's drive motor. Typical fuel cell systems comprise a fuel cell stack. The fuel cell stack includes several fuel cell elements, each with two electrodes and a membrane arrangement between the two electrodes. Within the fuel cell stack, fuel reacts with an oxidizer via reverse electrolysis, thereby generating electricity. The fuel can be supplied to the fuel cell stack from at least one fuel tank in the vehicle. The oxidizer can be drawn from the ambient air.In the cathode system of the fuel cell system, it is important that the air supply to the cathode and / or the air exhaust from the cathode are hermetically sealed or at least as tightly sealable as possible to prevent fuel from escaping the fuel cell on the cathode side. Various valve systems are known in the prior art for this purpose.

[0003] The purpose of the present technology is to create an improved system for preventing fuel leakage from the fuel cell via the cathode system.

[0004] The aforementioned problem is solved by the patent claims. In particular, the aforementioned problem is solved by the fuel cell system according to claim 1 and the vehicle according to the dependent claim. Further advantages of the disclosed technology will become apparent from the dependent claims, the description, and the figures. Features described in connection with the fuel cell system also apply in connection with the vehicle, and vice versa, so that the disclosure always refers to and / or can refer to the individual aspects in a reciprocal manner.

[0005] According to a first aspect of the present technology, a fuel cell system for a vehicle is proposed. The fuel cell system comprises a fuel cell with an anode and a cathode, a cathode inlet path for directing cathode gas to the cathode, a cathode outlet path for directing cathode fluid away from the cathode, and a valve assembly for controlling the cathode gas flow in the cathode inlet path and / or the cathode fluid flow in the cathode outlet path. The valve assembly further comprises an inlet roller valve for controlling the cathode gas flow in the cathode inlet path and / or an outlet roller valve for controlling the cathode fluid flow in the cathode outlet path.

[0006] Within the framework of the technology proposed here, it was found that rotary valves can be sufficiently fluid-tight not only against any air currents, but also against fuel such as hydrogen, which can flow from the cathode into the cathode inlet path and / or the cathode outlet path via air. Furthermore, it was found that sealing a rotary valve for the proposed application is simpler and more reliable than with a conventional throttle valve. In addition, rotary valves can have a longer service life compared to conventional throttle valves, while being comparatively easy to manufacture. Moreover, it has been found that rotary valves can be installed surprisingly easily and reliably in the fuel cell system.

[0007] A conventional throttle valve, as used here, can be understood as a disc-shaped throttle valve that is rotatable and / or adjustable about a central axis. The roller valve can have a radial through-opening. The roller valve can have a single through-opening. The through-opening can have a circular cross-section. The roller valve can be set to a closed position, a released position, and various partial-release or partial-lock positions between the closed and released positions. In the released position, the passage of cathode gas to the cathode and / or the passage of cathode outlet fluid away from the cathode is allowed. In the closed position, the passage of cathode gas to the cathode and / or the passage of cathode outlet fluid away from the cathode is prevented.A 90° rotation of the roller slide allows switching between the release and locking states. Various partial release states or corresponding partial locking states can be set by a rotation of less than 90°. The roller slide can have a cylindrical and / or roller-shaped element that rotates around its axis, thereby releasing or closing openings of different sizes.

[0008] The fuel cell system is preferably configured for mobile applications such as vehicles. The fuel cell system can be configured to provide electrical power to at least one of the vehicle's drive units. The drive unit can be a machine, such as an electric motor, used to propel the vehicle. The term "fuel cell" can refer to a single fuel cell or a fuel cell stack containing multiple fuel cells. In its simplest form, the fuel cell is an electrochemical energy converter that transforms fuel and oxidant into reaction products, generating electricity and heat in the process. The anode and cathode of a single fuel cell can be separated by an ion-selective or ion-permeable separator.If the fuel cell is configured in the form of a fuel cell stack, the anode can be understood as an anode area of ​​the fuel cell stack and the cathode as a cathode area of ​​the fuel cell stack.

[0009] The cathode inlet path can be understood as a path and / or a conduit through which reactant gas, such as oxygen or an oxygen-containing gas mixture, such as air, is transported to the cathode. The cathode outlet path can be understood as a path and / or a conduit through which exhaust gases and / or residual products of the reaction in the fuel cell, as well as excess gases, are removed from the cathode. Controlling can be understood as adjusting, regulating, and / or controlling.

[0010] According to one embodiment of the fuel cell system described here, the inlet roller valve can be arranged directly upstream of the cathode in the cathode inlet path and / or the outlet roller valve directly downstream of the cathode in the cathode outlet path. This effectively prevents the escape of unwanted gases from the fuel cell into certain areas of the cathode system and / or into the surrounding environment. A position directly upstream of the cathode can be understood as a position as close as possible to the cathode. In this case, no special and / or large functional components are designed and / or positioned between the valve assembly and a cathode inlet in the cathode inlet path. The inlet roller valve can, for example, be positioned downstream of a humidifier and upstream of the cathode.A position directly downstream of the cathode can be understood as a position as close to the cathode as possible. In this case, it is possible that no special and / or large functional components are designed and / or positioned between the valve assembly and a cathode outlet in the cathode outlet path. Smaller functional components, such as sensor components, may be located there. The outlet roller valve, for example, may be positioned upstream of a humidifier and downstream of the cathode.

[0011] The fuel cell system proposed here can further feature: - an inlet valve housing defining an inlet housing volume, and at least one inlet sliding ring, wherein the inlet roller valve and the inlet sliding ring are positioned in the inlet housing volume, the inlet sliding ring being in sliding contact with a lateral surface of the inlet roller valve, and wherein the inlet roller valve and the inlet sliding ring form an inlet fluid channel for guiding the cathode gas when the inlet roller valve is in a release position and / or - an outlet valve housing defining an outlet housing volume, and at least one outlet sliding ring, wherein the outlet roller valve and the outlet sliding ring are positioned in the outlet housing volume, wherein the outlet sliding ring is in sliding contact with a lateral surface of the outlet roller valve, and wherein an outlet fluid channel for guiding the cathode outlet fluid is formed by the outlet roller valve and the outlet sliding ring when the outlet roller valve is in a release position.

[0012] The sliding ring provides a simple and reliable way to create an effective sealing function on the respective roller valve. The sliding ring can be mounted coaxially to the fluid channel or fluid path within the valve housing. Each sliding ring can form a transition channel section to the adjacent roller valve in the cathode inlet path and / or the cathode outlet path. The sliding ring can be cylindrical or substantially cylindrical, although it does not necessarily have to be a perfect circular cylinder.

[0013] The respective sliding ring can be supported on a lateral surface of the adjacent roller valve. This allows the transition channel section formed by the respective sliding ring to create a fluid-dynamically advantageous transition. The sliding contact between the respective sliding ring and the adjacent roller valve can be understood to mean that the sliding ring can be configured and designed such that it at least partially contacts the adjacent roller valve during operation of the fuel cell system.

[0014] Furthermore, in the proposed fuel cell system, it is possible for the inlet sliding ring to be arranged upstream of the inlet roller valve in the cathode inlet path and / or for the outlet sliding ring to be arranged upstream of the outlet roller valve in the cathode inlet path. It has been found that such a positioning of the sliding ring results in a particularly effective sealing function. However, it is also possible for the inlet sliding ring and / or another inlet sliding ring to be arranged downstream of the inlet roller valve in the cathode inlet path and / or for the outlet sliding ring and / or another outlet sliding ring to be arranged downstream of the outlet roller valve in the cathode inlet path. When using the sliding rings in the fuel cell system, the desired sealing function may take precedence over the most frictionless possible movement of a roller valve against at least one sliding ring.Accordingly, in the proposed fuel cell system, unlike conventional applications of roller slides, it may be advantageous to position two sliding rings on a roller slide and / or to form a relatively large sliding surface between a sliding ring and a roller slide.

[0015] In the fuel cell system described here, it is possible for an inlet sliding surface between the inlet sliding ring and the inlet roller valve, and / or an outlet sliding surface between the outlet sliding ring and the outlet roller valve, to each have a width of at least 3 mm. This is intended to ensure that the respective sliding surface is large enough to achieve the desired sealing function of the sliding ring. The width can be understood as the circumferential width of the respective sliding surface. The width can correspond to the distance on an end face of the respective sliding ring from an inner surface of the sliding ring to an outer surface of the sliding ring. Depending on the specific application, the width can be at least 3 mm, at least 5 mm, at least 8 mm, or at least 10 mm.The respective sliding surface can be understood as a contact and / or sealing surface between the respective sliding ring and the adjacent roller slide.

[0016] Furthermore, the fuel cell system can feature: - an inlet sealing ring, wherein the inlet sliding ring has an inlet outer circumferential surface, wherein the inlet slide housing has an inlet inner circumferential surface, and wherein the inlet sealing ring is positioned between the inlet outer circumferential surface and the inlet inner circumferential surface and / or - an outlet sealing ring, wherein the outlet sliding ring has an outlet outer circumferential surface, wherein the outlet valve housing has an outlet inner circumferential surface and wherein the outlet sealing ring is positioned between the outlet outer circumferential surface and the outlet inner circumferential surface.

[0017] This allows for further improvement of the desired sealing function of the valve assembly. The sealing ring can be designed as an O-ring. The sliding ring can have an annular groove in which the sealing ring can be at least partially positioned. Alternatively or additionally, the valve body can have an annular groove in which the sealing ring can be at least partially positioned. This improves the sealing effect, allows for a particularly space-saving configuration of the valve assembly, and also prevents unintentional slippage of the respective sealing ring.

[0018] In the fuel cell system described and illustrated here, the inlet and / or outlet roller valves can each have a diameter between 1 cm and 5 cm. This makes the roller valve significantly larger than in conventional applications, enabling it to achieve the desired sealing effect. The inlet and outlet roller valves, the inlet sliding ring, and / or the outlet sliding ring can each be made of an elastomer such as FKM (fluoroelastomer), FFKM (perfluoroelastomer or perfluoroelastomer), HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene diene monomer rubber), and / or austenitic steel, or be constructed from the respective material. These materials are particularly compatible with hydrogen, ensuring the corresponding stability, durability, and / or long service life of the valve assembly in the fuel cell system.An austenitic steel can be understood as a selected stainless steel such as 304, 316, 316L, Alloy 926 SMO or Alloy 254 SMO, which is particularly resistant to hydrogen embrittlement.

[0019] Another aspect of the proposed technology concerns a vehicle with a fuel cell system as described above, wherein the fuel cell system is configured to generate electricity in the vehicle. The vehicle may have at least one electric motor for propelling the vehicle, and the fuel cell system may be configured to supply power to this at least one electric motor. The term "vehicle" can refer to a motor vehicle such as a motorized two-wheeler, a passenger car, or a truck. It can also refer to a road vehicle, an aircraft, a watercraft, a rail vehicle, a spacecraft, or a robot. Furthermore, the term "vehicle" can refer to a purely electric vehicle or a hybrid electric vehicle that, in addition to the at least one electric motor, has an internal combustion engine for propelling the vehicle.The vehicle in question can be understood as a so-called FCEV (Fuel Cell Electric Vehicle).

[0020] Further features and combinations of features of the proposed technology will become apparent from the following description of various embodiments, which are schematically illustrated in the figures. All features and / or advantages arising from the claims, the description, and the figures, including design details and spatial arrangements, can be significant both individually and in combination with one another.

[0021] They each show schematically: Fig. 1 a fuel cell system according to an embodiment of the present technology, Fig. 2 a valve arrangement of a fuel cell system according to a first embodiment of the present technology, Fig. 3 a valve arrangement of a fuel cell system according to a second embodiment of the present technology and Fig. 4 a vehicle with a fuel cell system according to an embodiment of the present technology.

[0022] Elements with the same function and mode of operation are each provided with the same reference symbols in the figures.

[0023] Fig. Figure 1 shows a fuel cell system 10 according to one possible embodiment. The fuel cell system 10 shown is a mobile PEM fuel cell system for a vehicle 100, which is located in Fig. The fuel cell system 10 is configured as shown in Figure 4. It comprises a fuel cell 11 with an anode 12 and a cathode 13. The fuel cell 11 is configured as a fuel cell stack (not shown in detail). The fuel cell system 10 includes an anode system 41 and a cathode system 42. The cathode system 42 has a cathode inlet path 14 for directing a cathode gas to the cathode 13 and a cathode outlet path 15 for directing a cathode outlet fluid away from the cathode 13. The fuel cell system 10 also includes a valve arrangement 20 for controlling a cathode gas flow in the cathode inlet path 14 and for controlling a cathode outlet fluid flow in the cathode outlet path 15.The valve arrangement 20 has an inlet roller valve 21 for controlling the cathode gas flow in the cathode inlet path 14 and an outlet roller valve 31 for controlling the cathode outlet fluid flow in the cathode outlet path 15. The inlet roller valve 21 and the outlet roller valve 31 are in the . Fig. 2 and Fig. 3 shown in further detail.

[0024] The in Fig. The cathode inlet path 14 shown in Figure 1 comprises a compressor 51, an intercooler 52, a humidifier 53, and the inlet rotary valve 21. The intercooler 52 is positioned downstream of the compressor 51, and the humidifier 53 is positioned downstream of the intercooler 52. The inlet rotary valve 21 and the associated part of the valve assembly 20 are positioned downstream of the humidifier 53 and directly upstream of the cathode 13. The humidifier 53 is configured as a heat exchanger not only as part of the cathode inlet path 14 but also as part of the cathode outlet path 15. The cathode outlet path 15 comprises a turbine 56, which is positioned downstream of the humidifier 53 and is operatively connected to the compressor 51. The outlet roller valve 31 is positioned in the cathode outlet path 15 upstream of the humidifier 53 and directly downstream of the cathode 13.The fuel cell system 10 shown also has a bypass 54 in which a bypass valve 55 is positioned.

[0025] Fig. 2 shows a part of the in Fig. The valve arrangement 20 shown in Figure 1 is located in the cathode inlet path 14 according to a first embodiment. As shown in Figure 1. Fig. As shown in Figure 2, the valve arrangement 20 has an inlet valve body 22, which defines an inlet housing volume 23, and an inlet sliding ring 24. The inlet roller valve 21 and the inlet sliding ring 24 are positioned in the inlet housing volume 23, with the inlet sliding ring 24 being in sliding contact with a cylindrical surface of the inlet roller valve 21, and with the inlet roller valve 21 and the inlet sliding ring 24 forming an inlet fluid channel 29 for guiding the cathode gas when the inlet roller valve 21 is in a release position P1. Fig. Figure 2 shows the inlet roller slide 21 in the release position P1. The inlet roller slide 21 would be in a locked position if it were rotated by 90°. The in Fig. The inlet sliding ring 24 shown in Figure 2 is arranged in the cathode inlet path 14 upstream of the inlet roller valve 21. An inlet sliding surface 28 between the inlet sliding ring 24 and the inlet roller valve 21 has a width of approximately 5 mm. The inlet sliding surface 28 corresponds to an end face of the inlet sliding ring 24, which is in contact with the inlet roller valve 21 in the released position P1 shown. The valve assembly 20 shown also includes an inlet sealing ring 25. The inlet sliding ring 24 has an inlet outer circumferential surface 26. The inlet valve housing 22 has an inlet inner circumferential surface 27. The inlet sealing ring 25 is designed as an O-ring and is positioned between the inlet outer circumferential surface 26 and the inlet inner circumferential surface 27. The inlet roller slide 21 has a maximum diameter of approximately 3 cm.The inlet roller valve 21 is made of austenitic steel and the inlet sliding ring 24 is made of a hydrogen-resistant elastomer.

[0026] Fig. 3 shows a part of the in Fig. 1 shown valve arrangement 20 in the cathode outlet path 15 according to a second embodiment. As in Fig. As shown in Figure 3, the valve arrangement 20 has an outlet valve housing 32, which defines an outlet housing volume 33, and at least one outlet sliding ring 34. The outlet roller valve 31 and the outlet sliding ring 34 are positioned in the outlet housing volume 33. The outlet sliding ring 34 is in sliding contact with a cylindrical surface of the outlet roller valve 31. In the released position P1 of the outlet roller valve 31 shown, an outlet fluid channel 39 is formed by the outlet roller valve 31 and the outlet sliding ring 34, through which cathode outlet fluid can be directed in the cathode outlet channel 15. The illustrated roller valve arrangement has an outlet sealing ring 35. The outlet sliding ring 34 has an outlet outer circumferential surface 36. The exhaust valve housing 32 has an inner circumferential surface 37. The exhaust sealing ring 35 is positioned between the outer circumferential surface 36 and the inner circumferential surface 37.The outlet sliding ring 34 is located in the cathode inlet path 15 upstream of the outlet roller valve 31. An outlet sliding surface 38, formed between the outlet sliding ring 34 and the outlet roller valve 31, has a width of approximately 10 mm. The outlet roller valve 31 has a maximum diameter of approximately 3 cm. The outlet roller valve 31 is made of austenitic steel, and the outlet sliding ring 34 is made of a hydrogen-resistant elastomer.

[0027] In Fig.Figure 4 shows a vehicle 100 in the form of a passenger car. The vehicle 100 has a fuel cell system 10 as described above, comprising a fuel cell 11 and a fuel tank 70 for fuel. The vehicle 100 also has two electric motors 60 for propelling the vehicle 100. The fuel cell system 10 is configured to generate electrical current in the vehicle 100, which can be used to power the electric motors 60.

[0028] The technology disclosed here allows for further design principles in addition to the embodiments shown. That is to say, the technology should not be considered limited to the embodiments explained with regard to the figures. For example, it is possible that a further inlet sliding ring is arranged downstream of the inlet roller valve 21 shown, and / or that a further outlet sliding ring is arranged downstream of the outlet roller valve 31 shown. Furthermore, it is possible that the inlet sliding ring 24 shown is positioned only downstream of the inlet roller valve 21, and / or that the outlet sliding ring 34 shown is positioned only downstream of the outlet roller valve 31. Reference symbol list 10 Fuel cell systems 11 Fuel cell 12 Anode 13 Cathode 14 Cathode inlet path 15 Cathode outlet path 20 Valve arrangement 21 Inlet roller slides 22 Inlet valve housings 23 Inlet housing volume 24 Inlet sliding ring 25 Inlet sealing ring 26 Inlet outer circumference area 27 Inlet inner circumferential area 28 Inlet sliding surface 29 Inlet fluid channel 31 Outlet roller valve 32 Outlet valve housings 33 Outlet housing volume 34 Outlet sliding ring 35 Outlet sealing ring 36 Outlet outer circumferential area 37 Outlet inner circumferential area 38 Outlet sliding surface 39 Outlet fluid channel 41 Anode system 42 Cathode system 51 compressors 52 Intercoolers 53 humidifiers 54 Bypass 55 Bypass valve 56 Turbine 60 electric motor 70 fuel tanks 100 vehicles P1 Release position

Claims

Fuel cell system (10) for a vehicle (100), comprising: - a fuel cell (11) with an anode (12) and a cathode (13), - a cathode inlet path (14) for directing a cathode gas to the cathode (13), - a cathode outlet path (15) for directing a cathode outlet fluid away from the cathode (13), - a valve arrangement (20) for controlling a cathode gas flow in the cathode inlet path (14) and / or for controlling a cathode outlet fluid flow in the cathode outlet path (15), - wherein the valve arrangement (20) comprises an inlet roller valve (21) for controlling the cathode gas flow in the cathode inlet path (14) and / or an outlet roller valve (31) for controlling the cathode outlet fluid flow in the cathode outlet path (15). Fuel cell system (10) according to claim 1, wherein the inlet roller slide (21) is arranged directly upstream of the cathode (13) in the cathode inlet path (14). Fuel cell system (10) according to one of the preceding claims, wherein the outlet roller slide (31) is arranged directly downstream of the cathode (13) in the cathode outlet path (15). Fuel cell system (10) according to one of the preceding claims, comprising: - an inlet valve housing (22) defining an inlet housing volume (23), and at least one inlet sliding ring (24), wherein the inlet roller valve (21) and the inlet sliding ring (24) are positioned in the inlet housing volume (23), wherein the inlet sliding ring (24) is in sliding contact with a lateral surface of the inlet roller valve (21), and wherein an inlet fluid channel (29) for guiding the cathode gas is formed by the inlet roller valve (21) and the inlet sliding ring (24) when the inlet roller valve (21) is in a release position (P1), and / or - an outlet valve housing (32) defining an outlet housing volume (33), and at least one outlet sliding ring (34), wherein the outlet roller slide (31) and the outlet sliding ring (34) are positioned in the outlet housing volume (33),wherein the outlet sliding ring (34) is in sliding contact with a cylindrical surface of the outlet roller slide (31) and wherein an outlet fluid channel (39) for guiding the cathode outlet fluid is formed by the outlet roller slide (31) and the outlet sliding ring (34) when the outlet roller slide (31) is in a release position (P1). Fuel cell system (10) according to claim 4, wherein the inlet sliding ring (24) is arranged in the cathode inlet path (14) upstream of the inlet roller slide (21) and / or wherein the outlet sliding ring (34) is arranged in the cathode inlet path (15) upstream of the outlet roller slide (31). Fuel cell system (10) according to one of claims 4 to 5, wherein an inlet sliding surface between the inlet sliding ring (24) and the inlet roller slide (21) and / or an outlet sliding surface between the outlet sliding ring (34) and the outlet roller slide (31) each has a width of at least 3 mm. Fuel cell system (10) according to one of claims 4 to 6, comprising: - an inlet sealing ring (25), wherein the inlet sliding ring (24) has an inlet outer circumferential surface (26), wherein the inlet slide housing (22) has an inlet inner circumferential surface (27) and wherein the inlet sealing ring (25) is positioned between the inlet outer circumferential surface (26) and the inlet inner circumferential surface (27) and / or - an outlet sealing ring (35), wherein the outlet sliding ring (34) has an outlet outer circumferential surface (36), wherein the outlet slide housing (32) has an outlet inner circumferential surface (37) and wherein the outlet sealing ring (35) is positioned between the outlet outer circumferential surface (36) and the outlet inner circumferential surface (37). Fuel cell system (10) according to one of the preceding claims, wherein the inlet roller valve (21) has a diameter in a range between 1cm and 5cm and / or the outlet roller valve (31) has a diameter in a range between 1cm and 5cm. Fuel cell system (10) according to one of the preceding claims, wherein the inlet roller valve (21), the outlet roller valve (31), the inlet sliding ring (24) and / or the outlet sliding ring (34) each comprise FKM, FFKM, HNBR, EPDM and / or an austenitic steel or consist of the respective material. Vehicle (100) with a fuel cell system (10) according to one of the preceding claims, wherein the fuel cell system (10) is configured to generate electrical current in the vehicle (100).

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