GAS LIQUID SEPARATOR IN AN ANODIC CIRCUIT OF A FUEL CELL FOR SEPARATING AT LEAST ONE LIQUID COMPONENT FROM A GASIC COMPONENT

Description

State of the art

[0001] The present invention relates to a gas-liquid separator in an anode circuit of a fuel cell for separating at least one liquid component from a gaseous component to which a medium is supplied via an inlet, wherein a separation of at least the liquid component of the medium takes place in at least one container, in particular for use in a fuel cell system of vehicles with a fuel cell drive.

[0002] In the future, gaseous fuels will play an increasingly important role in the automotive sector alongside liquid fuels. Hydrogen gas flows must be controlled, particularly in fuel cell-powered vehicles. The gas flows are no longer controlled discontinuously as with liquid fuel injection; instead, the gas is taken from at least one high-pressure tank and fed via an inlet line of a medium-pressure line system to an integrated valve-jet pump unit. This valve-jet pump unit feeds the gas to a fuel cell via a connecting line of a low-pressure line system. An exhaust gas, which consists primarily of unused hydrogen and an inactive component, particularly water and nitrogen, is recirculated from the fuel cell via a recirculation path.

[0003] DE 10 2014 220 891 A1 discloses a gas-liquid separator for separating a liquid component, in particular water, the water being referred to below as H2O, from a gaseous component, in particular exhaust gas, which is emitted by a fuel cell. This gas-liquid separator has at least one container, in particular a housing, into which the exhaust gas from an anode circuit of the fuel cell system is fed via an inlet pipe. In the container, H2O contained in the exhaust gas is separated from the exhaust gas. The exhaust gas, which contains, among other things, hydrogen, the hydrogen being referred to below as H2, is then returned to the anode circuit via an outlet pipe. The housing also has a drain connection via which separated and stored H2O is drained from the housing to the outside.

[0004] The gas-liquid separator known from DE 10 2014 220 891 A1 may have certain disadvantages.

[0005] Firstly, the exhaust gas from the anode circuit flows through the housing in such a way that only a portion of the H2O in the exhaust gas, particularly in its liquid state, can be separated. A large portion of the exhaust gas introduced into the housing flows unchanged back into the anode circuit via the outlet pipe. In this process, a significant portion of H2O, which is only present in gaseous form due to temperature and pressure conditions, for example, is always pumped back into the anode circuit. Furthermore, at least almost no separation of other components from the exhaust gas takes place, such as nitrogen (hereinafter referred to as N2), and / or impurities.This results in the disadvantage in the gas-liquid separator known from DE 10 2014 220 891 A1 that the gaseous medium flowing back from the housing into the anode circuit only partially contains H2 and a large part contains the components gaseous H2O and / or N2 and / or impurities and these are pumped back into the anode circuit of the fuel cell system. This reduces the efficiency of the fuel cell and thus of the fuel cell system and the components of the returned gaseous medium which are not H2 can damage the components of the anode circuit and / or the fuel cell and / or a piping system. On the other hand, at least one additional component must be arranged in the anode circuit of the fuel cell system in order to discharge the other components H2O and / or N2 and / or impurities from the anode circuit, for example in the form of a drain valve.

[0006] Document KR 2009 0019980 A discloses a fuel cell system with an anode gas recirculation of anode hydrogen, using a jet pump to build up a low pressure across a membrane that is permeable only to hydrogen. Part of the anode gas recirculation is fed to a membrane separator, where the hydrogen flows through the membrane, leaving nitrogen and water behind.

[0007] Document JP 2011 129377 A discloses an anode gas recirculation system for a fuel cell, using a membrane separator to separate nitrogen from a recirculation stream. Also disclosed is the use of a jet pump capable of generating a low pressure on a recirculation line.

[0008] Document JP 2005 183020 A discloses a fuel cell anode recycling system in which a membrane vapor-liquid separator is used to separate water from hydrogen in an anode recycling gas. Disclosure of the invention Advantages of the invention

[0009] With reference to claim 1, a gas-liquid separator is proposed in which a container has an interior space and a central flow region which are separated from one another by means of a membrane, wherein the flow region is fluidically connected to a connecting line or a tank line and an outflow line, wherein the interior space is fluidically connected, at least indirectly via a branch line, to the connecting line and wherein the interior space is fluidically connected at least indirectly to a return line and wherein a separation of a component of the gaseous medium from the H 2 takes place by means of the membrane.In this way, by separating the interior of the container from the flow region arranged in the container, which is in particular directly fluidically connected to an anode circuit of a fuel cell system, it is possible to prevent a large proportion of the components of the gaseous medium that are not H2 from flowing back into the anode circuit of the fuel cell system. The efficiency of the fuel cell system can thus be improved because the proportion of H2 in the gaseous medium to be pumped in the anode circuit is increased by reducing the proportion of components other than H2, in particular impurities and / or dirt particles, during the return from the interior to the flow region in the container by means of the membrane.The membrane can also at least partially reduce the proportion of H 2 O and N 2 that flows back into the flow area, since the membrane creates a flow resistance such that a larger number of lighter and / or smaller particles can pass through, while the proportion of larger particles that can pass through is at least reduced. In this case, the membrane acts in particular like a coarse filter that at least reduces the passage of large and / or heavy particles. In addition, the advantage can be achieved that the probability of damage to the other components of the anode circuit and / or a fuel cell and / or the piping system due to contamination can be reduced, whereby the service life of the entire fuel cell system, in particular the components of the anode circuit, can be reduced.

[0010] The subclaims relate to preferred developments of the invention.

[0011] According to a particularly advantageous embodiment of the gas-liquid separator, the membrane is designed as a semipermeable membrane, wherein the membrane is permeable to the H2 component of the medium and wherein the membrane is impermeable to at least the H2O component of the medium, in particular due to the molecular size of the respective component. Furthermore, the membrane can be impermeable to the N2 component of the medium. In addition to the liquid component, in particular H2O, a gaseous component N2 is separated from the medium by the gas-liquid separator.In this way, the advantage can be achieved that not only can impurities from the interior of the container not flow into the flow area due to the membrane, but in addition, the membrane can at least achieve an almost complete reduction in the H 2 O and / or N 2 flowing back from the interior into the flow area and / or the anode circuit. In this way, the efficiency of the fuel cell system can be improved. The membrane not only serves as a filter, through which the backflow of H 2 O and N 2 into the anode circuit is made more difficult, but the membrane forms a molecular structure, in particular with openings, through which almost exclusively H 2 can diffuse.This has the advantage that almost exclusively H2 flows from the interior through the membrane into the flow region and thus back into the anode circuit, thereby improving the efficiency of the fuel cell. In addition, the operating costs of the fuel cell system can be reduced. According to the invention, the membrane is designed as a wall of a first jet pump arranged at least partially in the container, wherein the flow region runs within the jet pump and wherein the jet pump has an intake region and / or a diffuser region. In addition, the gaseous medium in the anode circuit causes a pressure difference between the flow region and the interior when flowing through the intake region, whereby the movement of the H2 component through the membrane is supported, in particular due to an increased pressure gradient.In addition, in an exemplary embodiment of the gas-liquid separator, a second jet pump can be arranged in the anode circuit in addition to the first jet pump, wherein the second jet pump is at least indirectly fluidically connected to the tank line and / or an inflow line and / or the outflow line. In this way, the advantage can be achieved that by means of the geometric shape of the first jet pump, in particular in the region of a jet nozzle, and / or by means of an increased pressure in the central flow region of the first jet pump, an increased flow velocity can be achieved in the central flow region, whereby an increased negative pressure can be achieved in the region of the membrane. This increases the pressure gradient from the central flow region to the interior of the intermediate storage space. In particular, a pressure difference of at least almost 10 bar can be achieved.This makes it possible to almost completely separate the components H 2 O and N 2 from the medium and / or to separate at least a large proportion of the components H 2 O and N 2 from the medium. This ensures that the medium which is returned from the at least one container through the outflow line into the fuel cell via a first outlet consists almost entirely or at least largely of the component H 2 and that all other components, such as H 2 O and N 2 and / or contaminants are almost completely filtered out by the membrane. This makes it possible to increase the efficiency of the fuel cell since almost exclusively H 2 is required to generate energy, in particular in an anode region of the fuel cell.Furthermore, the efficiency of a recirculation pump and an integrated jet pump, which are optionally located between at least one tank and the fuel cell and ensure a continuous flow to the fuel cell, can be increased. This offers the advantage of improving the efficiency and / or effectiveness of the entire fuel cell system, thereby reducing operating costs. Furthermore, the arrangement of the flow area and the interior of the water separator in the tank allows for a compact and space-saving arrangement of the components.

[0012] According to an advantageous embodiment of the gas-liquid separator, a shut-off valve is located between the branch line or the connecting line and the interior of the container. Furthermore, a discharge valve is located between the interior of the container and the return line. This allows for more efficient filling, as needed, particularly when the proportion of H2O and / or N2 and / or contaminants in the medium to be pumped is increased. Another advantage is that the discharge valve prevents the gaseous medium from escaping from the interior of the container while an increased proportion of H2 is still present there. This improves the efficiency of the fuel cell system because less H2 is lost and the H2 can be recovered at least almost completely by means of the gas-liquid separator and fed back into the anode circuit.This means that less H2 needs to be pumped from a tank to operate the fuel cell system, and this has the advantage of reducing the operating costs of the fuel cell system and thus of the entire vehicle because less H2 is consumed. The discharge valve and return line also allow the H2O and / or N2 to be directed from the anode circuit into the cathode circuit, where it is needed for cooling, for example.

[0013] According to a particularly advantageous development, the gas-liquid separator has a sensor system, wherein the sensor system, in particular continuously, detects parameters of the connecting line and / or parameters of the interior of the container. Furthermore, in an exemplary embodiment, the shut-off valve and / or the discharge valve can be connected to the sensor system, in particular at least indirectly via a control device. In this way, the advantage can be achieved that it is possible to detect which operating states exist in the anode circuit and / or the connecting line and / or the interior, in particular the concentration of H 2 and / or H 2 O and / or N 2 and / or contaminants in the gaseous medium. On the basis of this data detected by the sensor system, the respective shut-off valve and / or discharge valve can be controlled by the control device.The control unit evaluates the data acquired by the sensors, for example using a CPU, and controls the opening or closing of the respective valve. This makes it possible to control when the interior is emptied and / or how long the emptying process lasts, allowing the residual amount to escape into the environment and / or be returned to the cathode circuit via the return line. This can be advantageous if an increased amount of H2O and / or N2 is required in the cathode circuit, depending on the operating state of the fuel cell and the entire fuel cell system. Furthermore, the operating costs of the entire vehicle can be reduced.Furthermore, when the gaseous medium is discharged from the interior via the discharge valve, the sensors and / or the control device can ensure that the hydrogen concentration in the medium is not so high that it forms a critical mixture, whereby a critical mixture is formed in particular from a ratio of 4% H 2 to 96% residual mixture.

[0014] According to an advantageous development, the gas-liquid separator has the recirculation pump, wherein the recirculation pump is arranged in the anode circuit. In this way, the advantage can be achieved that, over a wide range of operating states, such as the power state of the fuel cell and / or temperature and / or volume flow and / or pressure of the fuel cell system, a constant volume flow of the medium to be pumped can reach the fuel cell. A volume flow is generated and / or the gaseous medium is circulated by means of the recirculation pump. This occurs in a pressure range and / or temperature range and / or flow state in the anode circuit in which the jet pump cannot yet effect any, or at least an inconsistent, pumping and / or circulating flow of the gaseous medium through the anode circuit to the fuel cell.This is the case, for example, during a cold start of the vehicle, where the gaseous medium in the anode circuit is at least almost at rest and temperatures are near freezing. The recirculation pump builds up a corresponding volume flow and / or pressure in the anode circuit until it reaches a value at which the jet pump can also deliver optimally. This can ensure the reliable cold-start capability of the entire vehicle, even after long periods of inactivity and at low outside temperatures, especially below 0° Celsius.Furthermore, the responsiveness of the entire fuel cell system can be improved, for example, when the driver spontaneously requests power via a kickdown, during which the fuel cell system must briefly generate high electrical power, particularly the vehicle's maximum power, and thus be supplied with hydrogen. Furthermore, the efficiency and / or performance of the fuel cell can be increased.

[0015] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, numerous modifications are possible within the scope of the claims, which are within the scope of expert practice. drawing

[0016] An embodiment of the invention will be described in detail below with reference to the accompanying drawings. In the drawing: Figure 1 shows a schematic representation of a fuel cell system with a gas-liquid separator according to the invention in accordance with a first exemplary embodiment, Figure 2 shows a perspective sectional view of a membrane of the gas-liquid separator, Figure 3 shows a schematic representation of the fuel cell system with the gas-liquid separator according to the invention in accordance with a second exemplary embodiment, Embodiment of the invention

[0017] The representation according to Fig. 1 shows a fuel cell system 1 with a first embodiment of a gas-liquid separator 2 according to the invention, wherein the gas-liquid separator 2 separates a gaseous component N 2 from the medium in addition to the liquid component, in particular H 2 O. The components H 2 O and N 2 are separated from the medium, in particular from the component H 2 of the medium, by means of the gas-liquid separator 2 according to the invention.

[0018] In Fig. 1 1 shows the fuel cell system 1, in which a fuel cell 30, the gas-liquid separator 2 and an optional recirculation pump 9 are fluidically connected to one another by means of lines. The fuel cell 30 has an anode region 31 and a cathode region 32 and is used, in particular in a vehicle, for generating energy by means of a reaction between hydrogen, i.e. H 2 , and oxygen, i.e. O 2 . Air, in particular O 2 , is supplied to the cathode region 32 of the fuel cell 30 by means of a cathode circuit 29 in a flow direction IV. The gas-liquid separator 2 according to the invention is fluidically connected to the anode region 31 via a connecting line 4. In this case, a medium, which is in particular a recirculation medium from the anode region 31 of the fuel cell 30, is passed to the gas-liquid separator 2 for recirculation.The recirculation medium consists almost entirely of unused H 2 , which has not undergone a chemical and / or electrical reaction with oxygen within the fuel cell 30, as well as the waste products H 2 O and N 2 from the energy generation process within the fuel cell 30. In addition, further contaminants may be present in the gaseous medium, for example particles of the fuel cell 30 itself, which dissolve and / or break off as small, in particular molecular, particles during operation and are present as dirt particles in the anode circuit. The medium flows in a flow direction II of the anode side through the connecting line 4 at least indirectly into the gas-liquid separator 2. In the gas-liquid separator 2, the medium then flows either via the connecting line 4 into a central flow region 13 of a first jet pump 10, which is part of the gas-liquid separator 2.Alternatively, the medium can also flow via a branch line 7 and / or a shut-off valve 23 into an interior space 12 of at least one container 6 of the gas-liquid separator 2. The gas-liquid separator 2 serves to separate at least one liquid component, in particular H 2 O, from a gaseous component, in particular H 2 . The container 6 has an interior space 12 and the flow region 13, which are separated from one another by means of a membrane 34, wherein the flow region 13 is fluidically connected to the connecting line 4 and an outflow line 5. The interior space 12 is fluidically connected, at least indirectly via the branch line 7, to the connecting line 4. The interior space 12 is also fluidically connected, at least indirectly, in particular via a discharge valve 46, to a return line 19.Via the discharge valve 46, the remaining residual medium can be transferred from the interior 12 of the container 6 into a cathode circuit 29 of the fuel cell system 1 by means of the return line 19. The container 6 forms a container wall 17 that delimits the interior 12 from the outside. Alternatively, the remaining residual medium can be discharged from the interior 12 of the container 6 into the environment of the fuel cell system 1 and / or the vehicle. Within the container 6 of the gas-liquid separator 2, a gaseous and / or liquid component of the gaseous medium is separated from the H 2 by means of the membrane 34. The membrane 34 is designed as a wall 36 of the first jet pump 10 arranged at least partially in the container 6, wherein the flow region 13 extends within the jet pump 10 and wherein the jet pump 10 has a suction region 15 and / or a diffuser region 16.Furthermore, when flowing through the intake area 15, the medium causes a pressure difference between the flow area 13 and the interior space 12 due to a jet pump effect, which supports the movement of the component H 2 through the membrane 34 from the gaseous medium in the interior space 12 into the flow area 13.

[0019] In addition, Fig. 1 It is shown that the gas-liquid separator 2 according to the invention has a sensor system 22, wherein the sensor system 22, in particular continuously, detects parameters of the connecting line 4 and / or detects parameters of the interior 12 of the container 6. The shut-off valve 23 and / or the discharge valve 46 are connected to the sensor system 22, in particular at least indirectly via a control device. Based on the data detected by the sensor system 22, the respective shut-off valve 23 and / or discharge valve 46 can be controlled by means of the control device. The control device evaluates the data detected by the sensor system 22, for example by means of a CPU, and controls the opening and / or closing of the respective valve. This makes it possible to control when the interior 12 is emptied. The sensor system 22 measures, for example, the concentration of the components H 2 O and N 2 and / or other dirt particles in the interior 12 or in an anode circuit 25.In addition, the sensor system 22 can be used to measure a pressure in the region of the interior 12 and / or the remaining anode circuit 25. As soon as the sensor system 22 detects a specific value regarding the concentration of the components H2O and N2 and / or a pressure, the discharge valve 46 is activated and the components H2O and N2 and other particles are drained and / or removed by means of the discharge valve 46. According to an exemplary embodiment of the gas-liquid separator 2, the discharge valve 46 can be arranged at the lowest point of the interior 12 of the container 6 in order to ensure almost complete emptying by gravity. The control device can, for example, ensure the opening and / or closing of the respective valve by means of an electrical, mechanical, electronic or other type of actuator.In addition, a continuous opening and / or closing of the valve is possible, so that only a small volume flow of the gaseous medium can flow through the respective valve. In principle, the gas-liquid separator 2 can be controlled in several steps to efficiently reduce undesirable components, such as H 2 O and N 2 and / or contaminants, in the gaseous medium in the anode circuit 25. In the first step, in particular when the sensor system 22 detects increased values ​​of undesirable components in the gaseous medium in the anode circuit 25, the shut-off valve 23 is opened by means of the control device, so that a portion of the gaseous medium present in the anode circuit 25, in particular in the connecting line 4, is introduced into the interior 12 of the container 6.As soon as the interior space 12 is filled, whereby the discharge valve 46 can optionally be opened during filling, the shut-off valve 23 is closed and the separation of H2 by means of the gas-liquid separator 2 can begin. The H2 is then directed via the membrane 34 back into the flow area 13 and thus into the anode circuit 25.

[0020] In this case, by means of the first jet pump 10, which in particular has the suction region 15 and the diffuser region 16 in the region of the wall 36, a separation of the H 2 from the remaining medium located in the interior 12 of the container 6 is brought about and / or supported, in particular due to the high pressure level in the flow region 13 compared to the lower pressure level in the interior 12. The wall 36 is at least partially designed as a membrane 34.The gaseous medium flowing in flow direction II through the flow region 13 of the first jet pump 10 creates an increased pressure gradient between the interior space 12 and the flow region 13, in particular due to the at least partial pneumatic and / or fluidic separation, which promotes the diffusion of H2 through the membrane 34 and thus the proportion of H2 in the interior space 12 decreases more quickly and / or a larger amount of H2 can flow from the interior space 12 back into the anode circuit 25, in particular via the flow region. In the next step, in particular when there is a small residual amount of H2 in the interior space 12, the discharge valve 46 is opened so that the remaining contents can escape from the container 6. To support this process, the shut-off valve 23 can be opened so that the remaining contents can escape more efficiently and, for example, gaseous medium can flow in again from the anode circuit 25.

[0021] In Fig. 1 It is shown that in this first exemplary embodiment of the gas-liquid separator 2, in addition to the first jet pump 10, a second jet pump 26 is arranged in the anode circuit 25, wherein the second jet pump 26 is at least indirectly fluidically connected to a tank line 21 and / or an inflow line 3 and / or the outflow line 5. A driving medium is metered into the second jet pump 26 from a tank 27 via the tank line 21 by means of a metering valve 8. Together, the second jet pump 26 and the metering valve 8 form an integrated valve-jet pump unit 11, wherein in particular the line lengths between the second jet pump 26 and the metering valve 8 are designed to be as short as possible. In this second jet pump 26, the recirculation medium coming from the recirculation pump 9 is collected in a mixing area.Secondly, a gaseous propellant, in particular H 2 , flows into the second jet pump 26 and / or the metering valve 8 on a second flow path from outside the valve jet pump unit 11, the propellant coming from the tank 27 being under high pressure, in particular of more than 10 bar. The propellant is then discharged into the mixing area by means of an actuator of the metering valve 8, in particular intermittently, for example through a nozzle of the second jet pump 26. The H 2 flowing through the nozzle and serving as the propellant has a pressure difference to the recirculation medium. In order to create a so-called jet pump effect, the recirculation medium is conveyed via the outflow line 5 at a low pressure and a low mass flow into a second flow area of ​​the second jet pump 26.The propellant flows through the nozzle into the mixing area at the described pressure difference and at a high speed, which can be close to the speed of sound. After the recirculation medium has been accelerated by the propellant in the second jet pump 26 and the two media have mixed, the newly formed medium, which is almost entirely H2, flows through the inflow line 3 to the fuel cell 30, in particular to the anode area 31.

[0022] In Fig. 2 is a perspective sectional view of the membrane 34 of the gas-liquid separator 2, which serves as the wall 36 of the flow area 13. The membrane 34 is designed as a semipermeable membrane 34, wherein the membrane 34, as in Fig. 2 shown, is permeable to the component H 2 of the medium and wherein the membrane 34 is impermeable to the components H 2 O and N 2 and other dirt particles of the medium, in particular due to the molecular size of the respective component. The components H 2 O and / or N 2 and / or any dirt particles present in the medium are too large to diffuse through the structure, in particular the lattice structure of the membrane 34, while the component H 2 of the medium is small enough to diffuse through the structure of the membrane 34. Thus, in addition to the liquid component, in particular H 2 O, a gaseous and / or liquid component N 2 and / or dirt particles are separated from the medium by the gas-liquid separator 2. The gaseous medium flows from the interior space 12 to the membrane 34.The components H 2 O and / or N 2 and / or dirt particles cannot overcome the barrier membrane 34, while the H 2 can diffuse through the membrane 34 into the central flow region 13. The membrane 34 at least partially forms the wall 36 of the first jet pump 10.

[0023] Fig. 3 shows a schematic representation of the fuel cell system 1 with the gas-liquid separator 2 according to the invention according to a second exemplary embodiment. Here, the anode circuit 25 has only one jet pump 10, in particular the first jet pump 10. This first jet pump 10 is part of the gas-liquid separator 2. Furthermore, the gas-liquid separator 2 has at least one container 6, to which a medium coming from the fuel cell 30 is supplied at least indirectly via branch line 7 and the shut-off valve 23, wherein the container 6 has the container wall 17. At least the liquid component of the medium is separated in the container 6, wherein the separated component of the medium is discharged from the container 6 to the cathode circuit 29 via the return line 19.The discharge valve 46 can be located on the return line 19. The container 6 has the interior 12 and the flow region 13, which are separated from one another by the membrane 34, wherein the flow region 13 is fluidically connected to the tank line 21, in particular via the metering valve 8, and the outflow line 5, wherein the interior 12 is fluidically connected, at least indirectly via the branch line 7, in particular via the shut-off valve 23, to the connecting line 4. In this second exemplary embodiment, the first jet pump 10 and the metering valve 8 together form the integrated valve-jet pump unit 11, wherein in particular the line lengths between the first jet pump 10 and the metering valve 8 are designed to be as short as possible.The jet pump 10 is arranged in the container 6 such that its central flow region 13 extends at least partially within the container 6 and is at least partially encapsulated by the interior 12 by the wall 36, wherein the wall 36 is at least partially formed as a membrane 34. In the flow direction, the central flow region 13 first has the intake region 15 and then the diffuser region 16, wherein a jet pump effect is created in the region of the jet pump 10 by means of this geometric shape of the flow region 13. The medium coming from the tank 27 flows through the flow region 13 under high pressure, in particular above 10 bar.By means of the geometric shape of the flow region 13 of the jet pump 10, in particular in the region of a jet nozzle, and / or by means of an increased pressure in the central flow region 13 of the jet pump 10, an increased flow velocity can be achieved in the central flow region 13, whereby an increased negative pressure can be achieved in the region of the membrane 34. This increases the pressure gradient from the central flow region 13 to the interior 12 of the intermediate storage device. Thus, by means of the increased pressure difference, wherein in particular a high pressure level exists in the flow region 13 compared to the low pressure level in the interior 12, a separation of the H 2 from the remaining medium located in the interior 12 of the container 6 is brought about and / or supported. The wall 36 is at least partially designed as a membrane 34.The gaseous medium flowing in flow direction II through the flow region 13 of the first jet pump 10 creates an increased pressure gradient between the interior space 12 and the flow region 13, in particular due to the at least partial pneumatic and / or fluidic separation, which promotes the diffusion of H2 through the membrane 34 and thus the proportion of H2 in the interior space 12 decreases more quickly and / or a larger amount of H2 can pass from the interior space 12 back into the anode circuit 25, in particular via the flow region. Furthermore, in . Fig. 3 It is shown that the fuel cell 30 has the anode region 31 and the cathode region 32. Air, in particular O 2 , is supplied to the cathode region 32 via the cathode circuit 29 in the flow direction IV.

[0024] In Fig. 3It is also shown that the medium, which is in particular the recirculation medium from the anode region 31 of the fuel cell 30, is conducted from the anode region 31 in the flow direction II via the connecting line 4 and / or the branch line 7 to the gas-liquid separator 2, in particular into the interior 12 of the container 6. The gaseous medium coming from the anode region 31 can either flow via the connecting line 4 to the recirculation pump 9 or, alternatively, can be branched off from the connecting line 4 upstream of the recirculation pump 9 via the branch line 7 and conducted via the shut-off valve 23 to the gas-liquid separator 2. The gas-liquid separator 2 and the recirculation pump 9 are connected in parallel in the anode circuit 25 of the line system and the respective lines, such as the outflow line 5 coming from the gas-liquid separator 2, are each brought together again at a node 14.From node 14, the mixed gaseous medium then flows in flow direction II via the inflow line 3 into the anode region 31 of the fuel cell 30.

[0025] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, numerous modifications are possible within the scope defined by the claims.

Claims

1. Gas-liquid separator (2) in an anode circuit (25) of a fuel cell (30) for separation of at least one liquid constituent, in particular H2O, from a gaseous constituent, in particular H2, having at least one vessel (6) which is supplied at least indirectly via a connecting conduit (4) with a medium from an anode region (31) of the fuel cell (30), and / or a medium, in particular a motive medium, is supplied from a tank (27) via a metering valve (8) by means of a tank conduit (21), where at least the liquid constituent of the medium is separated out in the vessel (6), where the separated constituent of the medium is discharged from the vessel (6) via a return conduit (19), and the remaining gaseous component of the medium, in particular H2, is returned to the anode region (31) via a discharge conduit (5), characterized in that the vessel (6) has an interior (12) and a flow region (13) that are separated from one another by means of a membrane (34), where the flow region (13) is fluidically connected to the connecting conduit (4) or the tank conduit (21) and the outflow conduit (5), where the interior (12) is at least indirectly fluidically connected to the connecting conduit (4) via a branch conduit (7), and where the interior (12) is at least indirectly fluidically connected to the return conduit (19) and where a constituent of the gaseous medium is separated from the H2 by means of the membrane (34), where the membrane (34) takes the form of a wall (36) of a first jet pump (10) disposed at least partly within in the vessel (6), where the flow region (13) runs within the jet pump (10) and where the jet pump (10) has an intake region (15) and / or a diffuser region (16).

2. Gas-liquid separator (2) according to Claim 1, characterized in that the membrane (34) is designed as a semipermeable membrane (34), where the membrane (34) is permeable to the H2 constituent of the medium and where the membrane (34) is impermeable to at least the H2O constituent of the medium, particularly because of the molecular size of the particular constituent.

3. Gas-liquid separator (2) according to Claim 2, characterized in that that the membrane (34) is impermeable to the N2 constituent of the medium and hence, in addition to the liquid constituent, in particular H2O, a gaseous N2 constituent is separated from the medium by the gas-liquid separator (2).

4. Gas-liquid separator (2) according to any of the preceding claims, characterized in that the medium, as it flows through the intake region (15), causes a pressure difference between the flow region (13) and the interior (12), which assists movement of the H2 constituent back and forth through the membrane (34).

5. Gas-liquid separator (2) according to any of the preceding claims, characterized in that a barrier valve (23) is present between the branch conduit (7) or the connecting conduit (4) and the interior (12) of the vessel (6).

6. Gas-liquid separator (2) according to any of the preceding claims, characterized in that a discharge valve (46) is present between the interior (12) of the vessel (6) and the return conduit (19).

7. Gas-liquid separator (2) according to any of the preceding claims, characterized in that it has a sensor system (22), where the sensor system (22), in particular continuously, detects parameters of the connecting conduit (4) and / or detects parameters of the interior (12) of the vessel (6).

8. Gas-liquid separator (2) according to Claims 5 to 7, characterized in that the barrier valve (23) and / or the discharge valve (46) are in particular connected at least indirectly to the sensor system (22) via a control device.

9. Gas-liquid separator (2) according to any of the preceding claims, characterized in that a recirculation pump (9) is disposed in the anode circuit (25).

10. Gas-liquid separator (2) according to any of the preceding claims, characterized in that, in addition to the first jet pump (10), a second jet pump (26) is disposed in the anode circuit (25), where the second jet pump (26) is at least indirectly fluidically connected to the tank conduit (21) and / or an inflow conduit (3) and / or the outflow conduit (5).

11. Fuel cell system (1) comprising a gas-liquid separator (2) according to any of the preceding claims for controlling supply of hydrogen to and / or removal of hydrogen from the fuel cell (30).