Cell device with an air filter unit, and method for operating such a cell device

Abstract

The invention relates to a cell device (10) with a hot system part (62), wherein the hot system part (62) has at least one cell unit (12), wherein the cell device has an air supply line (20) which is designed to supply the hot system part (62) with air, in particular to supply the at least one cell unit (12) with air, wherein an air filter unit (64) which has a first filter (68a) and a second filter (68b) parallel to the first filter (68a) is arranged on the air supply line (20). It is proposed that the first filter (68a) is designed to be exchangeable and the air filter unit (64) has a first air barrier (78a) for the first filter (68a).

Description

[0001] Description

[0002] title

[0003] Cell device with an air filter unit, method for operating such a cell device

[0004] The invention relates to a cell device with an air filter unit according to the preamble of the independent claim. The invention further relates to a method for operating such a cell device.

[0005] State of the art

[0006] Fuel cell devices contain hot system components, especially fuel cell units, which are highly sensitive to contaminants in the fluids supplied. Therefore, fuel cell devices are typically equipped with an air filter. These air filters must be replaced regularly to ensure good filtration performance. If dust and dirt enter the hot system components during filter replacement, this can cause malfunctions and damage to the fuel cell device, especially the sensitive fuel cell units. Therefore, the fuel cell device must be turned off for filter replacement, which reduces operating life and efficiency.

[0007] Disclosure of the invention

[0008] Advantages

[0009] The present invention describes a cell device with a hot system part, wherein the hot system part has at least one cell unit, wherein the cell device has an air supply line which is designed to supply the hot system part with air, in particular to supply the at least one cell unit with air, wherein an air filter unit is arranged on the air supply line, which air filter unit has a first filter and a second filter parallel to the first filter. According to the invention, the first filter is designed to be replaceable and the air filter unit has a first air barrier for the first filter. This has the advantage that the first filter can be replaced during ongoing operation of the cell device.When replacing the first filter, the first air barrier can block a first air path associated with the first filter, preventing dirt or particles from entering the hot system components, while the hot system components are supplied with filtered air via the parallel second filter. This allows the cell device to be operated particularly efficiently; in particular, the time-consuming and energy-consuming up and down movement of the cell device for air filter replacement is eliminated.

[0010] A cell device is to be understood in particular as a device which is intended for the electrochemical conversion of at least two fluids. The cell device comprises a cell unit which electrochemically converts the two fluids, as well as components which supply the cell unit with electricity, i.e. which discharge and / or supply electrical energy, and components which supply the cell unit with the two fluids. The supplies can be active - for example via supply lines, pumps, fluid reservoirs, etc. - or passive - for example using ambient air as the fluid - without active transport. The cell device advantageously also comprises components for the removal and / or recycling of the converted fluids. The cell device advantageously also comprises components for heat transport, in particular for regulating the temperature of the cell unit, for example for the utilization of waste heat.Examples of cell devices are fuel cell devices or electrolysis devices.

[0011] In this context, a cell unit is understood to mean, in particular, a unit with a plurality of electrochemical cells. Typically, the electrochemical cells are stacked one on top of the other in a cell unit. Examples of cell units include fuel cell units or electrolysis cell units.

[0012] An electrochemical cell is understood in particular to be an arrangement which provides usable electrical energy through chemical reactions or is intended for the chemical extraction or conversion of substances by applying a voltage. An electrochemical cell has at least two or more functional layers. The functional layers comprise at least two electrode layers and a separating layer or electrolyte layer. The electrode layers each function as an electron conductor and are conductively connected to the separating layer or electrolyte layer. Also important for the electrode layers are ion transport and catalytic activity or oxygen exchange capacity between the electrode layer and the gas phase. The separating layer or electrolyte layer has in particular the function of an ion conductor. Furthermore, the separating layer orAn electrolyte layer is provided for separating the two gas spaces, for example, the separation between air and fuel gas in a fuel cell. During operation, an electrochemical cell typically has at least two fluids actively or passively supplied to it, which are electrochemically reacted. A fluid can be liquid and / or gaseous.

[0013] In particular, an electrochemical cell should be understood to mean a fuel cell or an electrolysis cell. For example, the electrochemical cell is designed to convert a fuel into electrical energy by adding an oxidant in an electrochemical combustion process. Alternatively or additionally, the electrochemical cell can be designed to separate a fluid into at least two components in a separation process by adding electrical energy. Examples of electrochemical cells are electrolysis cells or fuel cells.

[0014] A fuel cell device is to be understood in particular as a device which forms in particular a, in particular functional, component, in particular a structural and / or functional component, of a fuel cell system or the entire fuel cell system. In this context, a fuel cell system is to be understood in particular as a system for stationary and / or mobile generation, in particular of electrical and / or thermal energy, using at least one fuel cell unit. A fuel cell system has one or a plurality of fuel cell units. Typically, a fuel cell system has components and lines which are provided for supplying fuel and air to the fuel cell unit. Furthermore, a fuel cell system has components and lines for discharging exhaust gases from the fuel cell unit.Fuel cell systems advantageously have a recirculation circuit, comprising components and lines, which is provided for returning unconverted fuel and / or unconverted air to the fuel cell unit. Overall, a fuel cell unit has at least one or a plurality of fans, which are provided for conveying a fluid, in particular a gaseous fluid. The fluid can in particular be a fuel, air, exhaust gas or a combination of the aforementioned. The fans can in particular be fans of an air supply, fans of a fuel supply, a fan of an exhaust gas discharge and / or a fan of a recirculation circuit. The fuel cell system advantageously has one or more heat exchangers, in particular for recovering heat from the exhaust gas orIn particular, to recirculate the anode exhaust gas and cathode exhaust gas to the fuel cell unit, and in particular to recirculate the fluids supplied to the fuel cell unit—in particular, air, fuel, and / or recirculated fluid. In this context, the terms heat exchanger and heat transfer device are used synonymously.

[0015] In this context, a fuel cell unit should be understood to mean, in particular, a unit comprising a plurality of fuel cells. Typically, the fuel cells in a fuel cell unit are stacked one on top of the other; such a fuel cell unit is also referred to as a fuel cell stack. A fuel cell is particularly intended to convert at least one chemical reaction energy of at least one, in particular continuously supplied, fuel gas, in particular hydrogen, and at least one oxidizing agent, in particular oxygen, in particular into electrical energy. The fuel cell can be designed, in particular, as a solid oxide fuel cell (SOFC). It is also conceivable for the fuel cell to be designed in the manner of a proton conductor or proton-conducting oxide or a proton-conducting oxide (PCO). Such fuel cells are also referred to as protonic ceramic fuel cells (PCFC).However, the present invention is independent of the type of fuel cell, so the electrolysis device also works for other types of fuel cells. Typically, a fuel cell unit consists of a plurality of fuel cells electrically connected in series.

[0016] A fuel supply is to be understood as a source for a fuel which is supplied to the fuel cell device. For example, the fuel supply can be a connection for an external fuel supply line, for example from a natural gas network or from a hydrogen cylinder. A fuel can be, for example, natural gas, hydrogen or a mixture of natural gas and hydrogen. In variants, other fuels and mixtures of fuels are also conceivable; for example, fuel B can comprise natural gas, hydrogen, methane, ammonia and / or coal gas or synthesis gas. Advantageously, the fuel cell device can also have two or more fuel supplies, so that operation with different fuels is possible, in particular, for example, a fuel supply for natural gas and a fuel supply for hydrogen.

[0017] In this context, a recirculation circuit or an anode recirculation circuit is to be understood in particular as a fluid connection or a fluid path which is intended to supply an anode exhaust gas containing fuel or hydrogen and water from at least one fuel cell unit to a mixing point or a mixing section at which the anode exhaust gas is mixed with the at least substantially pure fuel or hydrogen. In particular, the recirculation circuit is intended to resupply unreacted fuel or hydrogen to the fuel cell unit on the anode side. In particular, the mixture of the anode exhaust gas and the fuel or hydrogen is intended to be supplied to the fuel cell unit on the anode side. Typically, a recirculation circuit has a recirculation fan which is intended to move a recirculated material.The recirculation circuit may, in particular, comprise a fuel supply line and / or a recirculation line or anode exhaust line. A flow direction of the recirculate is also understood to include, in particular, a flow direction of a recirculate-fuel mixture.

[0018] A recirculate is understood, in particular, to be a fuel- or hydrogen- and water-containing anode exhaust gas from at least one fuel cell unit. A recirculate-fuel mixture, in the context of this invention, is understood to be a gas mixture of a fuel- or hydrogen- and water-containing anode exhaust gas from at least one fuel cell unit with fresh fuel.

[0019] In the context of the present invention, lines are understood to mean lines intended to carry a fluid. A fluid can in particular be liquid or gaseous. A fluid is understood to mean in particular air, fuel, recirculated material, and exhaust gases - in particular anode exhaust gas and cathode exhaust gas. For example, an air supply line is intended to carry air. A line typically connects two components of the fuel cell device in terms of fluid technology. It is also conceivable for a line to connect several components of the fuel cell device in series with one another in terms of fluid technology. For example, the air supply line can connect an air source to an air blower and the air blower to the fuel cell unit. It is conceivable for a line to be provided for different fluids depending on the operating state and / or depending on the line section.For example, it is conceivable for the recirculation to be injected into a fuel supply line at a mixing section, so that a mixture of the fuel and the recirculation flows downstream of the mixing section. For example, a line may comprise one or more pipes. In particular, a line may comprise several pipe sections, which, for example, fluidically connect different components.

[0020] An electrolysis device is to be understood in particular as a device which is intended for producing fuel from at least one basic material and electrical current - in particular hydrogen from electrical current and water - by electrolysis. The electrolysis device has an electrolysis unit which is supplied with a medium as the basic material - for example water - and advantageously the auxiliary medium. The medium is reduced in the electrolysis unit with the supply of electrical energy in a redox reaction, which also produces oxygen. In particular, the electrolysis unit produces a product gas which comprises the reduced medium and an exhaust gas which comprises the oxygen. The reduced medium is discharged from the electrolysis unit and represents the fuel, for example hydrogen.Accordingly, the electrolysis device has components and lines to supply the medium and fuel to the electrolysis unit, to provide the electrical energy, and to remove the reduced medium and exhaust gas from the electrolysis unit and, if necessary, to store them. Furthermore, the electrolysis device has components and lines to bring the respective fluids to the temperatures required for electrolysis and to process the waste heat generated in the electrolysis unit. An auxiliary medium should be understood in particular to be a sufficiently inert gas which is intended to expel the oxygen from the electrolysis unit. Advantageously, the auxiliary medium is also intended to heat or cool the electrolysis unit. Possible auxiliary media are, for example, air, CO2 or N2; air is typically used.

[0021] An electrolysis unit is understood, in particular, to be a component that has at least one electrolysis cell. Typically, an electrolysis unit has a plurality of electrolysis cells that are electrically connected in series, with the electrolysis cells advantageously being stacked. A stack of electrolysis cells is also referred to as an electrolysis stack. The electrolysis unit can also be designed as a stack module. A stack module is understood to mean a plurality of electrolysis stacks that can be electrically connected individually, in parallel, or in series, and are arranged, for example, on a common chassis or a common support or in a common housing.

[0022] The electrolysis cell is an electrochemical cell designed to chemically produce or convert substances through chemical reactions by applying an electrical voltage. The electrolysis cell has at least two electrode layers and a separating layer or electrolyte layer, which in particular functions as an ion conductor. The electrolysis cell preferably has an electrode layer designed as an oxidation electrode or air electrode and in particular designed for contact with the oxidant and / or a fission product. Preferably, at least one electrode layer is designed as a fuel electrode, in particular designed for contact with the fuel and / or another fission product. The air electrode defines an anode side of the electrolysis cell, and the fuel electrode defines the cathode side of the electrolysis cell.

[0023] The electrolysis cell is preferably a solid oxide electrolysis cell (SOEC), particularly a high-temperature SOEC. Alternatively, the electrolysis cell can also be designed as a proton-conducting ceramic electrolysis cell (PCEC) based on a proton-conducting oxide (PCO). However, the present invention is independent of the type of electrolysis cell; thus, the electrolysis device also functions for other types of electrolysis cells. For example, an electrolysis unit based on proton-permeable polymer membranes, such as proton exchange membranes or polymer electrolyte membranes (PEM), is also conceivable.

[0024] A fluid supplied to the cell unit should therefore be understood to mean, in particular, a fuel, air, oxygen, medium, auxiliary medium and / or recirculate.

[0025] A hot plant section should be understood to mean in particular the at least one cell unit and other components of the cell device which are in close thermal contact with the cell unit. The hot plant section typically has heat exchangers which are provided for the direct return of the waste heat from the cell unit. In fuel cell devices, for example, the fuel cell unit, a cathode heat exchanger, an anode heat exchanger, an afterburner and / or a reformer are components of the hot plant section. The components of the hot plant section are advantageously separated from the other components of the cell device by thermal insulation and / or a housing for these components. The hot plant section is also referred to as the hot balance of plant (hot BoP) or hotbox.

[0026] An air filter unit is understood in particular to be a device designed to filter particles of a certain size or larger from the air. The air filter unit has at least one filter and, if applicable, a housing, holders or fastenings for the at least one filter, at least one air path or corresponding lines, and a corresponding connection to the air supply line in order to guide the filtered air to the hot part of the system. The filter itself can be, for example, an electrostatic precipitator, centrifugal filter, gravity filter, and / or mechanical filter. The filter is advantageously a mechanical filter which retains the particles by means of a filter medium through which the air flows, in particular a membrane. The filter advantageously has a woven or knitted fabric - in particular a paper and / or fabric.The filter advantageously has pores or meshes so that particles larger than the pores are separated from the air by the filter. The filter is advantageously designed to separate particles larger than 20 pm, advantageously larger than 10 pm, particularly advantageously larger than 10 pm. For example, the filter can have pores or meshes that are 5 pm in size. In this way, particles, especially critically sized dust particles, can be filtered out.

[0027] The fact that the second filter is parallel to the first filter should be understood in particular to mean that the second filter is connected in parallel to the first filter in terms of flow with regard to the supplied air. Advantageously, the air filtered by the first filter is initially guided through a first air path and the air filtered by the second filter is initially guided through a second air path, wherein the first air path and the second air path are brought together at a junction point and both air flows are led together into the air supply line. The first air barrier is designed in particular to block the first air path of the first filter. The first air barrier is designed in particular to be repeatedly blockable and openable again. An optional second air barrier is designed in particular to block the second air path of the second filter. The second air barrier is designed in particular to be repeatedly blockable and openable again.

[0028] Advantageous further developments of the cell device are possible due to the features listed in the subclaims.

[0029] The cell device is further improved if the second filter is designed to be replaceable and the air filter unit has a second air barrier for the second filter. This allows both the first and second filters to be replaced during operation. This allows for maintenance and replacement of the entire air filter unit while the cell device is in operation.

[0030] It is advantageous if the air barrier of at least one filter is designed to allow air to pass through an air path of this filter in a neutral position when this filter is installed, and to block the air path of this filter in a blocked position when this filter is removed from the air filter unit. In particular, the corresponding air barrier is designed to automatically change from the neutral position to the blocked position when the filter is removed. This enables particularly simple and error-free filter changes. For this purpose, the air barrier advantageously has means for detecting the presence of the filter and means for opening or blocking the air path depending on the presence of the filter. For example, the air barrier can have a sensor that detects the presence of the filter and an electronically controllable closure of the air path that is opened or closed depending on the sensor signal.However, mechanical air barriers are also conceivable, in which a closure element for the air path is in mechanical contact with the filter and is pushed over the air path by the movement of the filter when the filter is removed.

[0031] An advantageous mechanical implementation of the air barrier is one in which the air barrier has a closure element for mechanically closing an air path, which closure element has a contact element for releasably coupling to the associated filter, such that the closure element is coupled to the associated filter in the neutral position and is held in a position that does not block the associated air path. Once the filter is installed, the closure element is coupled to the filter and thus held in the neutral position. The coupling element can be a mechanical coupling, for example via a positive connection between two interacting elements - for example, interlocking hooks on the filter and on the closure element - a connection via an adhesive, or an electromagnetic coupling, for example via a permanent magnet.If the filter is removed and the coupling via the coupling element is released, the closure element is no longer held in the neutral position and can move into the closure position, for example by a gravitational force and / or by a suction force of an air blower arranged downstream of the air filter unit in the direction of flow.

[0032] In advantageous variants, the contact element is designed as a locking element. Accordingly, the closure element has a first locking element, for example, a locking lug or a locking hook, and the filter has a second locking element complementary to the first locking element, so that the first locking element can couple with the second locking element and form a locking connection.

[0033] The air barrier is further improved if the air barrier has a spring element configured to move a closure element into the blocking position for mechanically closing an air path after removal of the corresponding filter. This ensures that the closure element moves into the blocking position. Accordingly, the spring element is tensioned or pre-tensioned during filter installation, so that upon removal of the spring element, the spring element relaxes and moves the closure element into the blocking position.

[0034] In an advantageous variant, the air barrier has a closure plate as a closure element for mechanically closing an air path, which, in the blocked position, largely covers the associated air path along its cross-section in an airtight manner. The closure plate is advantageously inserted into the air path along its extension direction or plate plane. The air filter unit advantageously has at least one filter housing for one of the filters, which has a main extension direction that is aligned against a flow direction of the air supply line. This enables a particularly compact air filter unit. Furthermore, an advantageous construction is possible in which the air path is arranged or connected at one end of the filter housing with respect to the main extension direction and the closure element - in particular a closure plate - is arranged in the neutral position at the other end of the filter housing.Advantageously, the filter housing is designed such that when the filter is removed, the closure element can be moved along the main extension direction onto the air supply line.

[0035] The fact that the main extension direction is aligned counter to the flow direction of the air supply line should be understood in particular to mean that the main extension direction does not extend along the flow direction. The flow direction of the air supply line is determined by the flow direction in the air supply line at the air filter unit. In particular, the main extension direction is arranged at an angle to the flow direction or forms an angle with it, advantageously an angle between 50° and 120°, particularly advantageously between 70° and 100°, particularly advantageously between 80° and 90°.

[0036] Also advantageous is a cell device according to the present invention which is designed as a fuel cell device and which, in particular, has at least one fuel cell unit in the hot part of the system. This protects the fuel cells of the fuel cell unit, which, especially as SOFC fuel cells, are particularly sensitive to dirt. This increases the reliability and service life of the fuel cell device.

[0037] Also advantageous is a method for operating a cell device according to the present invention, wherein first, an old first filter is removed from the air filter unit and the first air barrier is moved to a blocking position. Subsequently, a new first filter is installed in the air filter unit and the first air barrier is moved to a neutral position. Such a maintenance method is particularly simple and reliable. Drawings

[0038] The drawings illustrate exemplary embodiments of the cell device and explain them in more detail in the following description.

[0039] Figure 1 is a schematic representation of the fluidic circuitry of a cell device,

[0040] Figures 2 A and 2 B show an air filter unit with an air barrier in neutral position, each in a perspective view and a sectional view,

[0041] Figures 3 A and 3 B show an air filter unit with an air barrier in the locking position, each in a perspective view and a sectional view, and

[0042] Figure 4 is a schematic representation of a method for operating the cell device.

[0043] Description

[0044] In the different versions, identical parts have the same reference numbers.

[0045] Figure 1 shows a schematic circuit diagram of an embodiment of a cell device 10. The cell device 10 is designed, for example, as a fuel cell device 10 for the conversion of pure hydrogen as fuel or of a natural gas-hydrogen mixture with a high hydrogen content as fuel. Such fuel cell devices 10 typically do not require a reformer for the fuel. The fuel cell device 10 comprises, for example, a fuel cell unit 12 as the cell unit 12. In the embodiment shown, the fuel cell unit 12 is designed as a fuel cell stack, which has a plurality of fuel cells, in this case solid oxide fuel cells (SOFC), as electrochemical cells.

[0046] A fuel, in the case shown a natural gas-hydrogen mixture, is supplied to the fuel cell unit 12 from a fuel source 14 via a fuel supply line 16. The fuel is a fluid. The fuel supply line 16 is a supply line 16 for the fluid fuel. The fuel supply line 16 is designed to supply the fuel to the cell unit 12. More precisely, the fuel is supplied to an anode side 12b of the fuel cell unit 12. For example, the fuel source 14 is a gas connection for an external fuel supply line, which provides a natural gas-hydrogen mixture. In alternative variants, it is conceivable for the fuel source 14 to have a gas pressure cylinder with fuel. In variants, the fuel can be, for example, hydrogen and / or natural gas.For example, a shut-off valve 44 is fluidically connected directly downstream of the fuel source 14 in the fuel flow direction in the fuel supply line 16. For example, a mass flow controller 46 for the fuel is fluidically connected directly downstream of the shut-off valve 44 in the fuel flow direction in the fuel supply line 16. In this way, the fuel flow required for the operation of the fuel cell unit 12 can be adjusted.

[0047] Air is supplied to the fuel cell unit 12 from an air source 18 via an air supply line 20. The air is a fluid. The air supply line 20 is a supply line 20 for the fluid air. The air supply line 20 is designed to supply the air to the cell unit 12. More precisely, the air is supplied to a cathode side 12a of the fuel cell unit 12. For example, an air blower 48 is arranged on the air supply line 20 in a fluidically connected manner between the air source 18 and the fuel cell unit 12. The air blower 48 is provided for supplying the air to the fuel cell unit 12 or its cathode side 12a. The air blower 48 is advantageously controllable, or the air flow strength can be adjusted. In this way, the air flow required for the operation of the fuel cell unit 12 can be adjusted.In the exemplary embodiment, the air source 18 is designed as an opening for outside air, which has an air filter. The air filter is intended to filter out pollutants and / or impurities from the air.

[0048] In the fuel cell unit 12, the fuel is electrochemically converted with the help of oxygen from the air, generating electrical energy and heat. The electrical energy is absorbed and converted, for example, by power electronics 22 connected to the fuel cell unit 12. For example, the direct current of the fuel cell unit 12 can be converted into an alternating voltage for external use.

[0049] After the electrochemical conversion in the fuel cell unit 12, the exhaust gas or cathode exhaust gas generated on the cathode side 12a is discharged from the fuel cell unit 12 via a cathode exhaust line 24a. The exhaust gas or anode exhaust gas generated on the anode side 12b is discharged from the fuel cell unit 12 via an anode exhaust line 24b. The cathode exhaust gas contains unused air or unused oxygen, while the anode exhaust gas may contain unconverted fuel.

[0050] For example, the cathode exhaust gas is conducted via the cathode exhaust line 24a from the fuel cell unit 12 to an afterburner 26. For example, a portion of the anode exhaust gas is conducted via the anode exhaust line 24b from the fuel cell unit 12 to the afterburner 26. The anode exhaust line 24b has a flow splitter 34, which divides the portion of the anode exhaust line 24b fluidically connected to the fuel cell unit 12 into a second portion of the anode exhaust line 24b and a recirculation line 36. The anode exhaust gas flowing from the anode side 12b is divided at the flow divider 34 into a first partial flow, which is fed to the afterburner 26 via the anode exhaust gas line 24b, and a second partial flow, which is fed to a recirculation circuit 38 via the recirculation line 36. By means of the afterburner 26, the anode exhaust gas or, if applicable,The unconverted fuel contained therein is burned with the admixture of the cathode exhaust gas or the oxygen contained therein in the air, thereby generating additional heat. The exhaust gases from the afterburner 26 are conducted via an exhaust line 28 into an exhaust outlet 30. The exhaust gases are then discharged from the fuel cell device 10 through the exhaust outlet 30.

[0051] Advantageously, the waste heat from the exhaust gases of the fuel cell unit 12, in particular the cathode exhaust gas and the anode exhaust gas or the exhaust gas from the afterburner, is returned to the fuel cell unit 12. In the exemplary embodiment, the fuel cell device 10 has a cathode heat exchanger 32a. The cathode heat exchanger 32a is provided to transfer heat from the exhaust gases flowing from the fuel cell unit 12 or the afterburner 26 to the air, which is supplied to the fuel cell unit 12 or its cathode side 12a via the air supply line 20. In this way, the efficiency of the fuel cell device 10 can be increased. In the exemplary embodiment, the cathode heat exchanger 32a is arranged upstream of the fuel cell unit 12 on the air supply line 20, relative to the direction of air flow.Advantageously, the cathode heat exchanger 32a is arranged downstream of the air blower 48 on the air supply line 20, relative to the direction of air flow. In the exemplary embodiment, the cathode heat exchanger 32a is arranged downstream of the afterburner 26 on the exhaust line 28, relative to the direction of exhaust gas flow.

[0052] In particular, the afterburner 26 is fluidly connected to the cathode heat exchanger 32a via the exhaust gas line 28.

[0053] In the exemplary embodiment, the fuel cell device 10 has an anode heat exchanger 32b. The anode heat exchanger 32b is provided to transfer heat from the anode exhaust gases flowing from the fuel cell unit 12 or its anode side 12b to the fuel, which is supplied to the fuel cell unit 12 or its anode side 12b via the fuel supply line 16. In this way, the efficiency of the fuel cell device 10 can be further increased. In the exemplary embodiment, the anode heat exchanger 32b is arranged upstream of the fuel cell unit 12 on the fuel supply line 16, relative to the flow direction of the fuel. In the exemplary embodiment, the anode heat exchanger 32b is arranged downstream of the fuel cell unit 12 and downstream of the flow divider 34 on the recirculation line 36, relative to the flow direction of the anode exhaust gas.In particular, the flow divider 34 is fluidly connected to the anode heat exchanger 32b via the recirculation line 36. In variants without the afterburner 26, it is conceivable that the anode heat exchanger 32b is fluidly connected to the fuel cell unit 12 via the anode exhaust line 24b.

[0054] In the exemplary embodiment, the recirculation circuit 38 is provided for recirculating a portion of the anode exhaust gases from the anode side 12b of the fuel cell unit 12. Such recirculation circuits 38 are also referred to as anode recirculation circuits. Typically, recirculation circuits 38 have a mixing section 40, into which a recirculate is fed into the fuel feed line 16, where the recirculate is mixed with fresh fuel. A recirculate is to be understood in particular as the portion of the anode exhaust gas that is recirculated, i.e., fed back to the fuel feed line 16 via the recirculation line 36. In the exemplary embodiment shown in Figure 1, the mixing section 40 is arranged in a direction perpendicular to the direction of flow of the fuel orof the fuel mixed with the recirculate on the fuel supply line 16 is arranged fluidically after the fuel source 14 and before the fuel cell unit 12, for example before the anode heat exchanger 32b.

[0055] Recirculation circuits 38 typically have a recirculation fan 42, which is provided for conveying the recirculate and / or fuel, in particular the fuel-recirculate mixture, to the fuel cell unit 12. In the exemplary embodiment shown in Figure 1, the recirculation fan 42 is arranged on the fuel supply line 16. With respect to the flow direction of the fuel or the fuel mixed with the recirculate in the fuel supply line 16, the recirculation fan 42 is arranged, for example, downstream of the mixing section 40 and upstream of the anode heat exchanger 32b.

[0056] The recirculation circuit 38 advantageously has a condenser heat exchanger 50. The condenser heat exchanger 50 is provided for condensing the recirculate or for condensing the water vapor from the recirculate. For example, the condenser heat exchanger 50 is arranged on the recirculation line 36. In the exemplary embodiment, the condenser heat exchanger 50 is arranged downstream of the anode heat exchanger 32b and upstream of the mixing section 40 with respect to the flow direction of the recirculate. In this way, during operation, the recirculate first flows through the condenser heat exchanger 50, where the water vapor is at least partially condensed. The recirculate then flows through the mixing section 40, where fresh fuel is added to the recirculate. The recirculate-fuel mixture then flows through the recirculation fan 42.

[0057] In the exemplary embodiment shown in Figure 1, the recirculate in the condenser heat exchanger 50 is cooled by air from the air supply line 20. For example, the fuel cell device 10 has a bypass line 52, which is intended to guide a portion of the air flow from the air supply line 20 into the condenser heat exchanger 50. The air supply line 20 has, for example, a three-way valve 54, which is connected to the bypass line 52. The three-way valve 54 is controllable and enables adjustment of the portion of the air flow that is branched off from the air line into the bypass line 54. The branched air flows through the bypass line 54 into the condenser heat exchanger 50 and from there is guided via a further section of the bypass line 54 into a return section 56, which connects the bypass line 54 to the air supply line 20.The air diverted at the three-way valve 54 is fed back into the air supply line 20 at the return section 56. With respect to the direction of air flow through the air supply line 20, the three-way valve 54 is arranged fluidically downstream of the air source 18 and advantageously upstream of the air blower 48. With respect to the direction of air flow through the air supply line 20, the return section 56 is arranged fluidically between the three-way valve 54 and the air blower 48.

[0058] By means of the adjustable three-way valve 54, in particular the air flow through the condenser heat exchanger 50 can be adjusted, so that in particular the cooling capacity or the heat extracted from the recirculate can be adjusted. In particular, a condensation temperature can be adjusted in this way by means of the three-way valve 54.

[0059] In the exemplary embodiment, a condensate drain 58 is connected to the condenser heat exchanger 50, which is intended to drain the condensate from the condenser heat exchanger 50. For example, the condensate drain 58 fluidically connects the condenser heat exchanger 50 to a condensate drain 60.

[0060] Some of the components of the fuel cell device 10 form a hot system part 62 of the fuel cell device 10. Typically, the hot system part 62 comprises the fuel cell unit 12 and other components that are in close thermal contact with the fuel cell unit 12, in particular heat exchangers, which are provided for the direct return of the waste heat from the fuel cell unit 12 to the fuel cell unit 12. In the exemplary embodiment, the hot system part 62 comprises the fuel cell unit 12, the cathode heat exchanger 32a, the anode heat exchanger 32b, and the afterburner 26.

[0061] The air supply line 20 has an air filter unit 64, which is arranged at the air source 18. For example, the fuel cell device 10 draws in air from the environment. The air filter unit 64 has, for example, an opening for air, which represents the air source 18. In variants, however, it is conceivable for the air filter unit 64 to be connected to an external air supply line, which carries, for example, compressed air. The air filter unit 64 is arranged upstream of the hot system part 62 in the flow direction 66 of the air flowing through the air supply line 20. In particular, the air filter unit 64 is arranged upstream of the fuel cell unit 12 or its cathode side 12a in the flow direction 66 of the air flowing through the air supply line 20. Advantageously, the air filter unit 64 is arranged upstream of the cathode heat exchanger 32a in the flow direction 66 of the air flowing through the air supply line 20.For example, the air filter unit 64 is arranged in the flow direction 66 of the air flowing through the air supply line 20 in terms of flow technology upstream of the air blower 48 and advantageously upstream of the three-way valve 54.

[0062] Figure 2A shows a perspective view of the air filter unit 64 with the first filter 68a mounted. Figure 2B shows a side view of a section through a first filter housing 70a of the first filter 68a along its main extension direction 72. The air filter unit 64 has, for example, two filters 68, a first filter 68a and a second filter 68b. The first filter 68a is arranged in a first filter housing 70a, the second filter 68b in a second filter housing 70b. In the perspective shown in Figure 1, the second filter 68b is not visible; the second filter 68b and the second filter housing 70b are identical in design to the clearly visible first filter 68a and the second filter housing 70b.

[0063] The first filter 68a or the first filter housing 70a is connected to the air supply line 20 via a first air path 74a. The second filter 68b or the second filter housing 70b is connected to the air supply line 20 via a second air path 74b. As can be clearly seen, the main extension directions 72 of the two filter housings 70 are arranged essentially perpendicular to the flow direction 66 of the air in the air supply line 20. The dashed line 76 illustrates, by way of example, how an air flow flows through the first filter 68a into the first housing 70a, from there through the first air path 74a into the air supply line 20. During normal operation, air can now be drawn in in parallel through both filters 68a and 68b, and the filtered air is supplied to the hot system part 62 via the air supply line 20.

[0064] In the sectional view in Figure 2B, it can be clearly seen that the first air path 74a is arranged at one end of the first filter housing 70a with respect to its main extension direction 72. The first filter 68a is arranged at the opposite end of the first filter housing 70a. Figure 2B illustrates the first air barrier 78a in a neutral position. For example, the first air barrier 78a has a first closure element 80a, which is embodied, for example, as a closure plate 82a. In the exemplary embodiment, the closure element 80a is arranged in the neutral position between the first filter 68a and the first air path 74a. For example, the closure plate 82a extends along the main extension direction 72.

[0065] The closure element 80a is detachably coupled to the first filter 68a by a first contact element 84a. For example, the first contact element 84a is designed as a locking element.

[0066] Figures 3A and 3B depict the air filter unit 64 and the first filter housing 70a of Figure 2 with the first filter 68a removed and the first air barrier 78a in a locked position. In the perspective view of Figure 3A, the first filter 68a is missing from the first filter housing 70a, while the second filter 68b is clearly visible in the second filter housing 70b.

[0067] In the sectional view of Figure 3B, it can be seen that, compared to Figure 3A, the closure element 80a has been pushed over the first air path 74a in the main extension direction 72 and closes it. In the blocked position, no air can flow through the first air path 74a. As can be clearly seen, the first air barrier 78a has a first spring element 86a, which is designed, for example, as a spiral spring. The first spring element 86a extends from the intended contact point with the removed first filter 68a or the receiving point for the first filter 68a to the closure element 80a in the blocked position. The closure element 80a was pushed from the neutral position into the blocked position by the first spring element 86a. In the neutral position shown in Figure 2B, the first spring element 86a is arranged, invisibly compressed, between the first filter 68a and the first closure element 80a and tensioned on the contact element 84.After removing the first filter 68a and releasing the contact element 84, the first spring element 86a relaxes and pushes the closure element 80a into the locking position via the first air path 74a. In this state, the first air path 74a is hermetically sealed. The hot system part 62 is supplied with air filtered by the second filter 68b via the second air path 74b.

[0068] Figure 4 shows a method 90 for operating or maintaining the fuel cell device 10. In a first step S1, an old first filter 68a is removed from the air filter unit 64 and the first air barrier 78a is brought into a locking position by the first spring element 86a. In a subsequent second step S2, a new first filter 68a is inserted into the air filter unit 64. When inserting the first filter 68a, the closure element 80a is pushed into the neutral position until the locking connection of the first contact element 84a engages, wherein the first

[0069] Spring element 86a is tensioned. In this way, the first air lock 78a is returned to a neutral position.

Claims

Claims 1. Cell device (10) with a hot system part (62), wherein the hot system part (62) has at least one cell unit (12), wherein the cell device has an air supply line (20) which is designed to supply the hot system part (62) with air, in particular to supply the at least one cell unit (12) with air, wherein an air filter unit (64) is arranged on the air supply line (20), which air filter unit has a first filter (68a) and a second filter (68b) parallel to the first filter (68a), characterized in that the first filter (68a) is designed to be replaceable and the air filter unit (64) has a first air barrier (78a) for the first filter (68a).

2. Cell device (10) according to claim 1, characterized in that the second filter (68b) is designed to be replaceable and the air filter unit (64) has a second air barrier (78b) for the second filter (68b).

3. Cell device (10) according to one of the preceding claims, characterized in that the air barrier (78) of at least one filter (68) is arranged to allow air to pass through an air path (74) of this filter (68) in a neutral position when this filter (68) is mounted, and to block the air path (74) of this filter (68) in a blocking position when this filter (68) is removed from the air filter unit (64).

4. Cell device (10) according to claim 3, characterized in that the air barrier (78) has a closure element (80) for mechanically closing an air path (74), which has a contact element (84) for releasably coupling to the associated filter (68), so that the closure element (80) is coupled to the associated filter (68) in the neutral position and is held in a position not blocking the associated air path (74).

5. Cell device (10) according to claim 4, characterized in that the contact element (84) is designed as a locking element.

6. Cell device (10) according to one of claims 3 to 5, characterized in that the air barrier (78) has a spring element (86) which is designed to move a closure element (80) for mechanically closing an air path (74) after removal of the corresponding filter (68) into the blocking position.

7. Cell device (10) according to one of claims 3 to 6, characterized in that the air barrier (78) has a closure plate (82) as a closure element (80) for mechanically closing an air path (74), which, in the blocking position, covers the associated air path (74) along its cross section in a largely airtight manner.

8. Cell device (10) according to one of the preceding claims, characterized in that the air filter unit (64) has at least one filter housing (70) for one of the filters (68), which has a main extension direction (72) which is aligned against a flow direction (66) of the air supply line (20).

9. Cell device (10) according to one of the preceding claims, characterized in that the cell device (10) is designed as a fuel cell device (10).

10. A method (90) for operating a cell device (10) according to any one of the preceding claims, wherein first (S1) an old first filter (68a) is removed from the air filter unit (64) and the first air barrier (78a) is brought into a blocking position, then (S2) a new first filter (68a) is mounted in the air filter unit (64) and the first air barrier (78a) is brought into a neutral position.

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