DE102020200145A1 - Fuel cell system - Google Patents

Abstract

The present invention relates to a fuel cell system (1) with a fuel cell (4) and a channel system (6) for supplying a reactant to the fuel cell (4) and for removing exhaust gas from the fuel cell (4), an adsorption device in the channel system (6) (11) is arranged to adsorb pollutants from the reactants. Simplified operation of the fuel cell system (1) and increased operating time and service life result from the fact that the adsorption device (11) has two separate adsorption devices (12, 13) and can be operated in two operating modes (16, 17), with the respective operating mode ( 16, 17) one of the adsorption devices (12, 13) adsorbs pollutants from the reactants and the other adsorption device (12, 13) is regenerated by a fluid that was previously adsorbed with the other adsorption device (12, 13) pollutants.

Description

The present invention relates to a fuel cell system with a fuel cell, a duct system for supplying a reactant to the fuel cell and for removing exhaust gas from the fuel cell and with an adsorption device for removing pollutants from the reactants.

To operate a fuel cell, the fuel cell is supplied with a fuel and an oxidizing agent, which react in the fuel cell to form water or exhaust gas containing steam and thereby generate electrical energy. In an associated fuel cell system, a channel system is used to supply the reactants, also referred to below as reactants, and to remove exhaust gas from the fuel cell. Such fuel cell systems have a delivery device which delivers fluid in the channel system. It is also known to provide an adsorption device in the channel system, which adsorbs pollutants from the associated reactants and thus removes them. It is necessary to remove or at least reduce the pollutants before supplying the reactants to the fuel cell, since pollutants of this type disrupt the operation of the fuel cell and in particular can damage components of the fuel cell, in particular the electrodes and / or the electrolyte of the fuel cell, which can lead to a Malfunction and a reduced service life of the fuel cell.

Such a fuel cell system is from DE 102 30 283 A1 known. In this fuel cell system, an adsorption device is arranged in the channel system upstream of the fuel cell, which has a filter for adsorbing pollutants. The filter can be regenerated in order to allow the adsorption device to function over a longer period of time and / or to avoid an exchange of the adsorption device, in particular the filter, and / or to increase the time until a necessary exchange of the adsorption device, in particular the filter. To regenerate the filter, compressed air and / or heat is supplied to the filter. A standstill of the fuel cell is used to regenerate the adsorption device, that is, the regeneration is carried out when the fuel cell is out of operation.

The present invention is therefore concerned with the object of specifying an improved or at least different embodiment for a fuel cell system of the type mentioned at the beginning, which is characterized in particular by an increased service life of the fuel cell and / or an increased service life of the fuel cell system.

According to the invention, this object is achieved by the subject matter of independent claim 1. Advantageous embodiments are the subject of the dependent claims.

The present invention is based on the general idea of providing two separate adsorbers in a fuel cell system for removing pollutants from a reactant for operating a fuel cell and alternately using one of the adsorbers for adsorbing pollutants from the reactants and the other adsorber from the former Adsorber to regenerate purified fluid. In this way it is possible to operate the fuel cell system, in particular the fuel cell, without the interruptions required for the regeneration of the adsorber and thus to increase the operating time of the fuel cell system. The regeneration of the adsorbers made possible in this way also means that they can each be regenerated independently or with at least reduced dependence on the operation of the fuel cell, so that damage to the adsorber and / or the fuel cell is avoided or reduced. Because of the reliable removal of pollutants from the reactants, the efficiency of the fuel cell and thus of the entire fuel cell system is consequently also improved.

In accordance with the concept of the invention, the fuel cell system has the fuel cell and a duct system which is used to supply the reactants to the fuel cell and to remove exhaust gas from the fuel cell. The fuel cell system also has an adsorption device which is used to adsorb and thus remove pollutants from the reactants before the reactants are supplied to the fuel cell. A conveying device of the fuel cell system conveys fluid through the channel system. According to the invention, the adsorption device has a first adsorption device and a second adsorption device which is separate from the first adsorption device and which each serve to adsorb pollutants. The fuel cell system can be operated in a first operating mode and a second operating mode. In the first operating mode, reactant flows through the first adsorption device, which adsorbs pollutants from the reactant and thus removes them, the reactant then flowing to the fuel cell in order to supply the fuel cell with the reactant. In the first operating mode, fluid also flows downstream of the first adsorption device and thus after the first adsorption device has removed pollutants to the second adsorption device, around the to regenerate second adsorption device. Analogously to this and in the opposite way, in the second operating mode reactant flows through the second adsorption device, which adsorbs pollutants from the reactant and thus removes them, the reactant then flowing to the fuel cell in order to supply the fuel cell with the reactant. In the second operating mode, fluid flows downstream of the second adsorption device and thus, after the second adsorption device has adsorbed pollutants, to the first adsorption device in order to regenerate the first adsorption device. The fuel cell system also has a switching device for changing between the operating modes and a control device for operating the fuel cell system. The switching device is designed in such a way that it can be adjusted between a first state and a second state in order to switch between the operating modes. In the first state of the switching device, the reactant and the fluid flow according to the first operating mode and in the second state of the switching device according to the second operating mode. The control device is designed in such a way that it moves the switching device into the first state in the first operating mode and into the second state in the second operating mode.

In the present case, pollutants are to be understood as meaning those substances and compositions which disrupt the operation of the fuel cell or components of the fuel cell system and / or damage the fuel cell or components of the fuel cell system, in particular humidifier membranes, electrodes of the fuel cell and / or an electrolyte of the fuel cell, to lead. Such pollutants include in particular ammonia, sulfur dioxide, hydrocarbons or nitrogen oxides.

The respective adsorption device is expediently designed to adsorb pollutants of the type mentioned. For this purpose, the respective adsorption device preferably has an adsorption medium. The respective adsorption device for adsorbing pollutants advantageously has activated carbon as the adsorption medium.

The respective adsorption device is expediently designed in such a way that it can be regenerated. In the present case, regeneration is to be understood as a process in which pollutants bound and / or stored in the adsorption device are removed from the adsorption device by the flow in the respectively associated operating mode. The respective adsorption device is expediently designed in such a way that it is regenerated when the fluid flows through from which pollutants were previously adsorbed by the other adsorption device and thus removed. The respective adsorption device is expediently designed in such a way that the supply of heat and thus an increased temperature promotes regeneration.

In the present case, a reactant is to be understood as meaning a reactant required for operating the fuel cell, that is to say a fuel or an oxidizing agent. In particular, the reactant can also be a mixture that contains the fuel or the oxidizing agent.

The reactant is preferably the oxidizing agent or a mixture containing the oxidizing agent. In particular, the reactant is air.

The fuel cell can in principle be any type of fuel cell. It is conceivable that the fuel cell is a solid oxide fuel cell, also called SOFC for short.

In particular, the fuel cell can be one that has a membrane as the electrolyte. This means that the fuel cell can in particular be a polymer electrolyte fuel cell, also called PEM fuel cell for short, or a direct methanol fuel cell, also called DM fuel cell for short.

Of course, the fuel cell can also be part of a fuel cell stack that comprises several fuel cells.

The fluid according to the present invention is to be understood as any, in particular gaseous, fluid after flowing through at least one of the adsorption devices and thus after adsorbing pollutants. The fluid can therefore be the reactants after flowing through one of the adsorption devices for adsorbing pollutants and / or the exhaust gas.

In the respective operating mode, as described above, pollutants are adsorbed or removed from the reactants with one of the adsorption devices and the reactant is then passed to the fuel cell while the other adsorption device is being regenerated. For the sake of simplicity, the adsorption device that removes pollutants from the reactants in order to then lead the reactants to the fuel cell is referred to as the active adsorption device, whereas the adsorption device that is regenerated is referred to as the passive adsorption device. The reactant which has flowed through the active adsorption device is also referred to below as the purified reactant.

In preferred embodiments, the conveying device is arranged in such a way that it conveys both the reactant and the fluid through both adsorption devices in both operating modes, ie in the first operating mode and in the second operating mode. In both operating modes, the delivery device thus conveys both reactant through the active adsorption device and fluid through the passive adsorption device. For this purpose, the delivery device can be arranged in such a way that the fluid flowing through the passive adsorption device is tapped from a pressure side of the delivery device. The pressure side of the conveying device is that side of the conveying device on which there is an increased pressure compared to a suction side of the conveying device. In particular, the pressure side is arranged downstream of the conveying device. It is thus possible to operate the fuel cell system in both operating modes with the same delivery device. This leads to increased efficiency and simplified operation of the fuel cell system.

To operate the fuel cell system in the operating modes, in particular to switch between the operating modes, the fuel cell system can in principle be designed in any way.

It is conceivable to provide the channel system with a supply channel which is used to supply the reactant to the fuel cell system. The channel system also has a switching section through which a first flow path, which leads through the first adsorption device, and a second flow path, which is separate from the first flow path and leads through the second adsorption device, lead. Downstream of the switching section, a feed path leads to the fuel cell in order to supply the fuel cell with purified reactants. In addition, downstream of the switching section, a return path leads to the switching section. The switching device is designed in such a way that, in the first state, it fluidly connects the supply channel to the supply path via the first flow path. As a result, reactant flows to the first adsorption device, which adsorbs pollutants from the reactants and thus removes them, and then purified reactant via the feed path to the fuel cell. In addition, in the first state, the return path is connected to the second flow path. As a result, fluid flows through the second adsorption device via the return path in order to regenerate the second adsorption device. Analogously to this and in the opposite way, in the second state of the switching device, the feed channel is connected to the feed path via the second flow path. The reactant then flows through the second adsorption device, which adsorbs pollutants from the reactants and thus removes them, and then via the feed path to the fuel cell. In the second state, the switching device also connects the return path to the first flow path. As a result, fluid flows through the first adsorption device in order to regenerate the first adsorption device. This allows simple and efficient operation of the fuel cell system.

In particular, a reliable separation of purified reactants and the fluid flowing through the passive adsorption device is thus possible. This prevents the fluid from reaching the fuel cell after flowing through the passive adsorption device and thus damaging it and / or components of the fuel cell system or at least reducing the corresponding risk.

A throttling is advantageously provided in the return path in order to limit a flow of fluid through the return path to the passive adsorption device. This in particular prevents an excessive flow of fluid to the passive adsorption device from reducing and / or increasing a supply of the fuel cell with purified reactants excessively and / or to an undesired extent. The throttling can be implemented, for example, by a corresponding throttle valve.

It is also conceivable to arrange a check valve in the return path, which prevents the flow from the passive adsorption device to the fuel cell.

The switching device can be designed as desired for adjustment between the first state and the second state and / or have any desired components.

The switching device advantageously has at least one valve which can be adjusted between corresponding positions for adjusting the switching device between the first state and the second state. The switching device can thus be implemented in a simplified and reliable manner. At least one of the at least one valves can be a multi-way valve.

Embodiments are considered advantageous in which the switching device has two valves, namely a first valve and a second valve. The respective valve can be adjusted between two positions. In addition, the switching section runs between the two valves. In particular, the switching section runs from the first valve to the second valve. The first valve is designed in such a way that, in a first position of the first valve, the feed channel is fluidically connected to the first flow path and fluidically separated from the second flow path. The second valve is like this configured that, in a second position of the second valve, the second valve fluidly connects the first flow path to the supply path and fluidically separates the second flow path from the supply path. The second valve is also designed such that in the first position it fluidly connects the second flow path to the return path and fluidically separates the first flow path from the return path. In addition, the first valve is designed in such a way that, in a second position of the second valve, it fluidly connects the supply channel to the second flow path and fluidically separates it from the first flow path. The second valve is designed such that, in a second position of the second valve, it fluidly connects the second flow path to the supply path and fluidically separates the first flow path from the supply path. The second valve is also designed such that in the second position it fluidly connects the first flow path to the return path and fluidically separates the second flow path from the return path. This means that the valves are each adjusted to the first position in the first state of the switching device and to the second position in each case in the second state of the switching device. Accordingly, the control device is designed in such a way that it moves the valves into the first position in each case in the first operating mode and into the second position in each case in the second operating mode.

At least one of the valves, advantageously the respective valve, is preferably a multi-way valve. In particular, the second valve is a 4/2 valve. It is also advantageous if the first valve is a 4/2 valve.

Alternatively, the switching device in the switching section can have a drum with two chambers which are separate from one another and in each of which an associated one of the adsorption devices is arranged. The drum thus has a first chamber, in which the first adsorption device is arranged, and a second chamber, separate from the first chamber, in which the second adsorption device is arranged. In addition, the drum has an inlet fluidically connected to the feed channel and a feed connector fluidically connected to the feed path. Furthermore, the drum has a return connection fluidically connected to the return path. The chambers together with the adsorption devices arranged therein can be moved between a first arrangement and a second arrangement. In the first arrangement, the inlet and the supply port are connected to the first chamber and the return port to the second chamber. In the first arrangement, reactant therefore flows through the feed channel and the inlet into the first chamber and flows through the first adsorption device, which functions as an active adsorption device. In addition, fluid flows via the return path and the return connection into the second chamber and thus through the second adsorption device, which functions as a passive adsorption device. Analogously to this and in the opposite way, in the second arrangement the inlet and the supply connection are fluidically connected to the second chamber and the return connection to the first chamber. Accordingly, reactant flows via the feed channel and the inlet into the second chamber and thus through the second adsorption device and then to the feed path, so that the second adsorption device functions as an active adsorption device. In contrast, fluid flows via the return channel and the return connection into the first chamber and thus through the first adsorption device, so that the first adsorption device functions as a passive adsorption device. The first arrangement thus corresponds to the first state of the switching device, whereas the second arrangement corresponds to the second state of the switching device. Consequently, the control device is designed in such a way that it moves the chamber into the first arrangement in the first operating mode and into the second arrangement in the second operating mode. Since the adjustment between the first state and the second state can thus take place without further valves, the pressure loss caused by the flow through valves is reduced in this way. The fuel cell system can thus be operated more efficiently.

The first arrangement and the second arrangement of the chambers can in principle differ from one another as desired, i. H. be realized by any movement of the chambers relative to each other. For this purpose, the chambers are advantageously rotatably received in the drum. For example, the chambers can be moved between the first arrangement and the second arrangement by rotating them about a common axis of rotation. This enables simple and reliable adjustment of the switching device and thus simplified operation of the fuel cell system.

It is conceivable that the return path runs between an extraction point in the feed path, hereinafter also referred to as the reactant extraction point, and the switching section. Thus, purified reactant flows as a fluid for regeneration to the passive adsorption device.

It is also conceivable that the return path runs between an extraction point arranged downstream of the fuel cell, hereinafter also referred to as an exhaust gas extraction point, of the duct system and the switching section. Thus, exhaust gas flows as a fluid for regenerating the passive Adsorption device via the return path to the passive adsorption device.

It is of course also conceivable to supply the passive adsorption device with both purified reactants and exhaust gas as a fluid for regeneration. For this purpose, the return path can run both from the reactant withdrawal point and from the exhaust gas withdrawal point to the switching section.

The fuel cell system advantageously has a humidifier which is integrated in the channel system and serves to humidify the reactant upstream of the fuel cell and thus before the reactant is supplied to the fuel cell. In particular, the humidifying device serves to humidify the purified reactants. The fuel cell system, in particular the fuel cell, can thus be operated more efficiently and with an increased service life. In particular, the humidifying device is integrated in the feed path. It is preferred here if the reactant removal point is arranged upstream of the humidifying device in the feed path. This prevents water or reactant containing water vapor from reaching the passive adsorption device or at least reducing the corresponding risk. Since moisture can damage and / or impair the respective adsorption device, such damage and / or impairments of the passive adsorption device are prevented or at least reduced in this way.

The arrangement of the humidification device in the feed path means that purified reactants flow through the humidification device. Damage and impairments of the humidifying device, which usually has at least one membrane for humidifying the reactant, caused by pollutants, are thus prevented or at least reduced.

The humidifying device is advantageously integrated in the channel system downstream of the fuel cell, fluidly separated from the supply path. The exhaust gas, which contains water or steam, is thus used to humidify the reactants and the operation of the fuel cell system is thus more efficient. It is preferred here if the exhaust gas extraction point is arranged downstream of the humidifying device in the duct system. In particular, the exhaust gas extraction point can be arranged downstream of the humidification device on the humidification device. This prevents water or fluid containing water vapor from reaching the passive adsorption device or at least reducing the corresponding risk. Since moisture can damage and / or impair the respective adsorption device, such damage and / or impairments of the passive adsorption device are prevented or at least reduced in this way.

Embodiments are considered advantageous in which the fluid flowing through the passive adsorption device then flows out of the fuel cell system. This in particular prevents fluid containing pollutants from subsequently reaching the fuel cell and thus damaging and / or impairing it.

Embodiments are preferred here in which the fluid flows out of the channel system via the switching device. This means that in at least one of the operating modes, advantageously in the respective operating mode, the fluid that has flowed through the passive adsorption device flows out of the channel system via the switching device. This leads to a simplified operation of the fuel cell system and / or a reliable separation between the flow paths.

In principle, the switching device can be designed in any way to discharge the fluid that has flowed through the passive adsorption device. It is particularly conceivable that the corresponding flow path is connected to the first valve or to an outlet of the drum.

The change between the first operating mode and the second operating mode can in principle be initiated as desired. In particular, the change takes place in such a way that the respectively active adsorption device frees the reactants from pollutants to a sufficient extent.

It is conceivable, for this purpose, to change between the operating modes at predetermined time intervals. In particular, it is conceivable to change between the first operating mode and the second operating mode at regular, in particular periodic, time intervals.

Alternatively or additionally, it is conceivable to switch between the first operating mode and the second operating mode when starting or ending the operation of the fuel cell system.

If the fuel cell system is equipped with a volume measuring device for determining the volume flowing through at least one section of the duct system, it is alternatively or additionally conceivable to switch between the first operating mode and the second operating mode depending on the supplied volume.

It is also conceivable to arrange a sensor device in the sewer system for determining the pollutant concentration in order to switch between the current operating mode and the other operating mode and thus between the first operating mode and the second operating mode when a predetermined pollutant concentration is exceeded. For this purpose, the sensor device is expediently connected to the control device in a communicating manner.

The sensor device is preferably arranged in the feed channel and thus determines the pollutant concentration between the fuel cell and the active adsorption device.

It goes without saying that the fuel cell system can also be operated in other operating modes in addition to the operating modes mentioned.

In particular, it is conceivable to operate the fuel cell system in a regular mode in which both adsorption devices function as active adsorption devices. Regular operation is particularly important when both adsorption devices do not require regeneration.

The fuel cell system can in principle be used in any application. In particular, the fuel cell system is used in applications in which an increased operating time of the fuel cell is desired and / or necessary. In such applications, by changing between the first operating mode and the second operating mode, the fuel cell system can be operated for increased operating times without interrupting the operation of the fuel cell.

The fuel cell system is used in particular in a motor vehicle. One should think in particular of those motor vehicles which require longer operating times, in particular longer journeys. As an example, reference is made here to commercial vehicles.

Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures on the basis of the drawings.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or on their own, without departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, with the same reference symbols referring to the same or similar or functionally identical components.

• 1 eine stark vereinfachte, schaltplanartige Darstellung eines Brennstoffzellensystems in einem ersten Betriebsmodus,
• 2 die Darstellung aus 1 bei einem zweiten Betriebsmodus des B ren nstoffze llensystem s,
• 3 das Brennstoffzellensystem im ersten Betriebsmodus bei einem anderen Ausführungsbeispiel,
• 4 einen Schnitt im Bereich eines Schaltabschnitts des Brennstoffzellensystems bei einem weiteren Ausführungsbeispiel und im ersten Betriebsmodus,
• 5 den Schnitt aus 4 beim zweiten Betriebsmodus des Brennstoffzellensystems.

It show, each schematically

• 1 a greatly simplified, circuit diagram-like representation of a fuel cell system in a first operating mode,
• 2 the representation 1 in a second operating mode of the fuel cell system,
• 3 the fuel cell system in the first operating mode in another embodiment,
• 4th a section in the area of a switching section of the fuel cell system in a further embodiment and in the first operating mode,
• 5 the cut out 4th in the second operating mode of the fuel cell system.

A fuel cell system 1 as it is for example in the 1 to 5 shown can be part of a motor vehicle, otherwise not shown 2 , especially commercial vehicles 3 , be. The fuel cell system 1 has a fuel cell 4th on, which is part of a fuel cell stack 5 can be. The fuel cell 4th consumes a fuel as well as an oxidizer as reactants to generate electrical energy. This creates water or exhaust gas containing water vapor, in particular water or water vapor. The fluid supply of the fuel cell 4th takes place via a canal system 6th of the fuel cell system 1 . With the sewer system 6th Preferably, as in the exemplary embodiments shown, the oxidizing agent, for example air, is supplied to the fuel cell 4th and removing exhaust gas from the fuel cell 4th . For conveying fluid through the channel system 6th instructs the fuel cell system 1 a conveyor 7th , especially a compressor 8th , which in the sewer system 1 is arranged on. The conveyor system sucks during operation 7th Fluid and promotes it in the direction of the fuel cell 4th . Accordingly, the downstream side of the conveyor becomes 7th also as a print side 9 and the upstream side of the conveyor 7th as suction side 10 designated. The fuel cell system 1 further comprises an adsorption device 11 which is used for adsorption and thus the removal of pollutants, for example ammonia, sulfur dioxide, hydrocarbons, nitrogen oxide and the like, from the reactants, in the present case from the oxidizing agent. The adsorption device 11 has a first adsorption device for this purpose 12th and a second adsorption device separate from the first adsorption device 13th with each of which pollutants can be removed from the reactants and thus purified reactants can be provided. The respective adsorption device 12th , 13th For this purpose, for example, has a filter 14th , especially an activated carbon filter 15th , on.

The fuel cell system 1 is in a first, in the 1 , 3 and 4th operating mode shown 16 and one in the 2 and 5 second operating mode shown 17th operable.

In the first operating mode 16 reactant flows through the first adsorption device 12th , wherein the first adsorbent 12th pollutants are adsorbed from the reactants and thus removed and consequently purified reactants are made available to the fuel cell 4th is fed. In the first operating mode 16 is also downstream of the first adsorption device 12th Fluid removed, so from the upstream side with the first adsorption device 12th Pollutants were adsorbed, and by the second adsorption device 13th led to the second adsorption device 13th to regenerate. During the regeneration, in particular adsorbed and / or deposited pollutants are removed from the second adsorption device 13th away. In the second operating mode 17th reactant flows through the second adsorption device 13th , wherein the second adsorption device 13th adsorbed pollutants from the reactants and thus removed, and the thus purified reactant of the fuel cell 4th is fed. In the second operating mode 17th is also downstream of the second adsorption device 13th Fluid removed, so from the upstream side with the second adsorption device 13th Pollutants were adsorbed, and by the first adsorption device 12th guided. As a result, the first adsorption device 12th regenerated, in particular adsorbed and / or deposited pollutants from the second adsorption device 13th away. The respective adsorption device is described below 12th , 13th , which adsorbs pollutants from the reactants and removes them to the reactants subsequently as purified reactants of the fuel cell 4th feed, as an active adsorption device 18th and the adsorption device 12th , 13th that is regenerated, as a passive adsorbent 19th designated. In the first operating mode 16 is therefore the first adsorption device 12th the active adsorption device 18th and the second adsorbent 13th the passive adsorption device 19th . In contrast, it is in the second operating mode 17th the second adsorption device 13th the active adsorption device 18th and the first adsorbent 12th the passive adsorption device 19th . Thus, the respective adsorption device 12th , 13th in one of the operating modes 16 , 17th can be regenerated without supplying the fuel cell 4th must be interrupted with reactant, i.e. without the fuel cell being operated 4th must be stopped.

Adjusting or changing between the first operating mode 16 and the second mode of operation 17th takes place with the help of a switching device 20th that are in the first operating mode 16 in a first state 21 and in the second operating state 17th into a second state 22nd is adjusted. For adjusting the switching device 20th instructs the fuel cell system 1 a control device 23 on, which is designed accordingly. The control device 23 is, as indicated with dashed lines, with the switching device 20th communicating connected.

In the exemplary embodiments shown, the channel system 6th a feed channel 24 for supplying the reactant to the fuel cell system 2 on. In the feed channel 24 can be a particulate filter 25th be arranged to remove particles from the reactant. In addition, the canal system 6th a switching section 26th on who the switching device 20th included or from the switching device 20th can be limited. In the switching section 26th a first flow path leads 27 through the first adsorption device 12th . In the switching section 26th is also one of the first flow path 27 fluidically separated second flow path 28 provided by the second adsorption device 13th leads. Downstream of the switching section 26th leads a feed path 29 to the fuel cell 4th , via the in the respective operating mode 16 , 17th purified reactant to the fuel cell 4th flows. It also leads downstream of the switching section 21 a return path 30th back to the switching section 21 . Via the return path 30th flows in the respective operating mode 16 , 17th Fluid for regenerating the passive adsorption device 19th to the passive adsorption device 19th .

In the exemplary embodiments shown, the switching device connects 21 in the first operating mode 16 the feed channel 24 via the first flow path 27 with the feed path 29 . In addition, there is a fluidic connection of the feed channel 24 with the second flow pad 28 and thus with the second adsorption device 13th interrupted. Furthermore, the return path 30th fluidically with the second flow path 28 connected. So this corresponds to the first state 21 the switching device 20th . In the second operating state 17th and thus in the second state 22nd the switching device 20th connects the switching device 20th the feed channel 24 via the second flow path 28 with the feed path 29 . In addition, the switching device separates 20th the first flow path 27 fluidically from the feed channel 24 . Furthermore, in the second state 22nd the first flow path 27 fluidically with the return path 30th connected.

In the exemplary embodiments shown, this flows through the passive adsorption device 19th flowing fluid over the switching device 20th from the sewer system 6th . To this end, the canal system points 6th an exhaust port 38 on.

In the exemplary embodiments shown, the conveying device is 7th in the feed path 29 arranged. Like that 1 to 3 can be removed, the fuel cell system 1 also a cooler 31 for cooling the reactants and a humidifier 32 have for moistening the reactant, which in each case in the feed path 29 are incorporated and thus cool and humidify the purified reactants.

In the 1 to 3 The switching device has shown embodiments 20th a first valve 33 and a second valve 34 on, each as a multi-way valve 35 are trained. The flow paths run here 27 , 28 between the valves 33 , 34 . In the first operating mode 16 and thus in the first state 21 the switching device 20th is the respective valve 33 , 34 in a first position 36 , 37 adjusted. That is, the first valve 33 in a first position 36 of the first valve 33 and the second valve 34 in a first position 37 of the second valve 34 is adjusted. The first valve 33 connects in the first position 36 the feed channel 24 with the first flow path 27 and separates the feed channel 24 from the second flow path 28 . The second valve 34 connects in the first position 37 the first flow path 27 with the feed path 29 and separates the second flow path 28 from the feed path 29 . In addition, the second valve connects 34 in the first position 37 the return path 30th with the second flow path 28 and separates the return path 30th from the first flow path 27 . The first valve 33 also connects in the first position 36 the second flow path 28 with the exhaust port 38 for discharging the fluid after flowing through the passive adsorption device 19th , in the first operating mode 16 so the second adsorption device 13th . In the second operating mode 17th and thus in the second state 22nd the switching device 20th are the valves 33 , 34 , each in a second position 39 , 40 adjusted. That is, the first valve 33 in a second position 39 of the second valve 33 and the second valve 34 in a second position 40 of the second valve 34 is adjusted. In the second position 39 of the first valve 33 connects the first valve 33 the feed channel 24 with the second flow path 28 and separates the first flow path 27 from the feed channel 24 . The second valve 34 connects in the second position 40 of the second valve 34 the second flow path 28 fluidically with the feed channel 29 and separates the first flow path 27 fluidically from the feed path 29 . In addition, the second valve connects 34 in the second position 40 the return path 30th with the first flow path 27 . The first valve 34 connects in the second position 39 the first flow path 27 fluidically with the outlet channel 38 .

In the embodiment of 1 and 2 is used to regenerate the passive adsorption device 19th purified reactant as fluid from the feed path 29 taken. The return path runs accordingly 30th between an extraction point 41 in the feed path 29 , hereinafter also reactant withdrawal point 41 called, and the switching section 26th , especially the second valve 34 . The reactant withdrawal point 41 is advantageous and, as shown, upstream of the humidifying device 32 arranged. In addition, the reactant withdrawal point 41 downstream of the cooler 31 be arranged.

In the embodiment of 3 , this in 3 in the first operating state 21 the second operating state is shown 22nd but analogous to 2 can be implemented, is used to regenerate the passive adsorption device 19th downstream of the fuel cell 4th Exhaust gas taken as a fluid. The return path runs accordingly 30th between an extraction point 42 , hereinafter also exhaust gas extraction point 42 called, and the switching section 26th , especially the second valve 34 . In the respective exemplary embodiment, the fluid is used to regenerate the passive adsorption device 19th downstream of the switching device 26th and thus downstream of the active adsorption device 18th taken. Here is in the embodiment of 1 and 2 the fluid is the purified reactant and in the embodiment of FIG 3 the fluid the exhaust gas. As in 3 shown in dashed lines, the return path 30th also correspond to a combination of both variants, ie both between the reactant withdrawal point 41 and the switching section 26th as well as between the exhaust gas extraction point 42 and the switching section 26th run away. Accordingly, the fluid can correspond to a mixture of purified reactant and exhaust gas.

In the embodiment of 3 is the humidifier 32 downstream of the fuel cell 4th and from the feed path 29 also separately in the sewer system 6th incorporated so that water or water vapor is transferred from the exhaust gas to the reactant to moisten the reactant. Here is the exhaust gas extraction point 42 downstream of the humidifier 32 , especially on the humidifier 32 , arranged.

In the exemplary embodiments shown, the respective extraction point is 41 , 42 in the sewer system 6th on the print side 9 the conveyor 7th arranged. The conveyor thus promotes 7th in both operating modes 16 , 17th both the reactants through the active adsorption device 18th and to the fuel cell 4th as well as the fluid through the passive adsorption device 19th .

In the exemplary embodiments shown, there is in the return path 30th a throttle device 43 , especially a throttle valve 44 , arranged to control the flow of the fluid to the passive adsorption device 19th to regulate, in particular to reduce.

In the 4th and 5 is another embodiment of the fuel cell system 1 shown, with the 4th and 5 a section through the fuel cell system 1 in the area of the switching section 26th demonstrate. Here shows 4th the first state 21 the switching device 20th and thus the first operating state 16 , whereas 5 the second state 22nd the switching device 20th and thus the second operating mode 17th shows. This embodiment differs from that in FIGS 1 to 3 Embodiments shown by the design of the switching device 20th . The ones in the 4th and 5 switching device shown 20th has a drum 45 with one with the feed channel 24 fluidly connected inlet 46 and one fluidically to the outlet channel 38 connected outlet 47 on. The drum 45 also has one with the feed path 29 fluidically connected supply connection 48 and one with the return path 30th fluidically connected return connection 49 on. In the example shown are the inlet 46 and the feed connector 48 arranged opposite one another. Also are the outlet 47 and the return port 49 arranged opposite one another. Inside the drum 45 has the switching device 20th a first chamber 50 and one from the first chamber 50 separate second chamber 51 on. In the first chamber 50 is the first adsorption device 12th and in the second chamber 51 the second adsorption device 13th arranged. The chambers 50 , 51 including the associated adsorption device incorporated therein 12th , 13th are between an in 4th shown first arrangement 52 and one in 5 second arrangement shown 53 movable and therefore adjustable. To this end, the chambers 50 , 51 and thus adsorption devices 12th , 13th be rotatable about an axis of rotation not shown and lying in the cutting plane. In the first arrangement 52 is the first chamber 50 and thus the first adsorption device 12th with the inlet 46 and the feed port 48 fluidically connected. The next is the first adsorption device 12th fluidically with the feed channel 24 and the feed path 29 connected. In contrast, in the first arrangement 52 the second chamber 51 and thus the second adsorption device 13th with the return connection 49 and the outlet 47 and consequently with the return path 30th and the outlet duct 38 fluidically connected. In the first arrangement 52 so functions the first adsorption device 12th as an active adsorption device 18th , whereas the second adsorption device 13th as a passive adsorption device 19th acts. In the second arrangement 53 are the chambers 50 , 51 arranged analogously in reverse. Here is the second chamber 51 fluidic with the inlet 46 and the feed port 48 and consequently with the feed channel 24 and the feed path 29 connected, whereas the first chamber 50 and thus the first adsorption device 12th fluidically with the return connection 49 and the outlet 47 and thus with the return path 30th and the outlet duct 38 are connected. In the second arrangement 53 thus functions the second adsorption device 13th as an active adsorption device 18th , whereas the first adsorption device 12th as a passive adsorption device 19th acts.

In the exemplary embodiments shown, the control device is 23 each designed in such a way that it is the switching device 20th in the first operating mode 16 in the first state 21 and in the second operating mode 17th in the second state 22nd adjusted.

Adjusting between the first operating mode 16 and the second mode of operation 17th can at predetermined, defined times, for example when the fuel cell system is started and / or stopped 1 , in particular of the associated motor vehicle 2 , respectively. The change can also take place at specified time intervals. It is also conceivable to switch between the first operating mode 16 and the second mode of operation 17th to be carried out if by the respectively active adsorption device 18th a given volume of the reactant has flowed. This can be done in the feed channel 24 and / or in the feed path 29 a device (not shown) for determining the mass flow can be provided.

Is the fuel cell system 1 Part of a motor vehicle 2 so you can switch between the operating modes 16 , 17th even after certain mileages of the motor vehicle have expired, in particular after specified mileage of the vehicle 2 , respectively.

As in the 1 to 3 shown, the fuel cell system 1 also a sensor device 54 have, which is designed in such a way that it reduces the concentration of pollutants in the sewer system 6th determined. The sensor device 54 is communicating with the control device 23 connected. A change can be made between the first operating mode 16 and the second mode of operation 17th take place when the sensor device 24 in the sewer system 6th a concentration of pollutants is determined which is above a predetermined target value. In the exemplary embodiments shown, the sensor device is 54 arranged in such a way that it reduces the concentration of pollutants in the feed path 29 and thus that of the active adsorbent 18th purified reactants determined. The sensor device 54 for example the concentration of pollutants between the conveyor 7th and the cooler 31 determine.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 10230283 A1 [0003]

Claims (15)

Fuel cell system (1), - with a fuel cell (4), - with a channel system (6) for supplying a reactant to the fuel cell (4) and for discharging exhaust gas from the fuel cell (4), - with one arranged in the channel system (6) Conveying device (7) for conveying fluid through the channel system (6), - with an adsorption device (11) in the channel system (6) for adsorbing pollutants from the reactants upstream of the fuel cell (4), characterized in - that the adsorption device (11 ) has a first adsorption device (12) for adsorbing pollutants and a second adsorption device (13), separate from the first adsorption device (12), for adsorbing pollutants, - that the fuel cell system (1) is designed such that it is in a first operating mode ( 16) and a second operating mode (17) can be operated, wherein in the first operating mode: • reactant through the first adsorption device (12) and then to Fuel cell (4) flows, • Fluid flows downstream of the first adsorption device (12) to the second adsorption device (13) and the second adsorption device (13) thus regenerates, whereby in the second operating mode: • Reactant through the second adsorption device (13) and then to the fuel cell (2) flows, • fluid flows downstream of the second adsorption device (13) to the first adsorption device (12) and thus regenerates the first adsorption device (12), - that the fuel cell system (1) has a switching device (20) which is used to switch between the first operating mode (16) and the second operating mode (17) can be adjusted between a first state (21) and a second state (22), - that the fuel cell system (1) has a control device (23) which is designed such that it the switching device (20) in the first operating mode (16) in the first state (21) and in the second operating mode (17) in the second state (22) adjusted. Fuel cell system according to Claim 1 , characterized in that the conveying device (7) is arranged in such a way that it conveys the reactants and the fluid through both adsorption devices (12, 13) in both operating modes (16, 17). Fuel cell system according to Claim 1 or 2 , characterized in - that the channel system (6) has a supply channel (24) for supplying the reactants, - that the channel system (6) has a switching section (26), - that a first flow path (27) through the switching section (26) the first adsorption device (12) leads, - that in the switching section (26) a second flow path (28) separated from the first flow path (27) leads through the second adsorption device (13), - that downstream of the switching section (26) a feed path (29) leads to the fuel cell (4), - that downstream of the switching section (26) a return path (30) leads to the switching section (26), - that the switching device (20) is designed in such a way that it • in the first state (21) the feed channel ( 24) connects via the first flow path (27) to the supply path (28) so that reactant flows via the first adsorption device (12) and the supply path (29) to the fuel cell (4), • in the first state (21) the return path ( 30) with the second stream connection path (28) so that fluid flows via the return path (30) through the second adsorption device (13), • in the second state (22) connects the supply channel (24) via the second flow path (28) to the supply path (29) , so that reactant flows via the second adsorption device (13) and the feed path (29) to the fuel cell (4), • in the second state (22) connects the return path (30) with the first flow path (27) so that fluid flows through the Return path (30) flows through the first adsorption device (12). Fuel cell system according to one of the Claims 1 to 3 , characterized in that the switching device (20) has at least one valve (33, 34) which in the respective state (21, 222) is adjusted to an associated position (36, 37, 39, 40). Fuel cell system according to Claim 4 , characterized in that - that the switching device (20) has a first valve (33) and a second valve (34), each of which can be adjusted between two positions (36, 37, 39, 40), - that the switching section (26) runs between the valves (33, 34), that the first valve (33) in a first position (36) fluidly connects the supply channel (24) with the first flow path (27) and fluidically separates it from the second flow path (28), - that the second valve (34) in a first position (37) fluidly connects the first flow path (27) to the supply path (29) and fluidically separates the second flow path (28) from the supply path (29), - that the second valve (34) in the first position (37) the second flow path (28) fluidly connects to the return path (30) and fluidically separates the first flow path (27) from the return path (30), - that the first valve (33) in a second position (39) the supply channel (24) with the second flow path (28) fluidly connects and fluidically separates from the first flow path (27), - that the second valve (34) in a second position (40) fluidly connects the second flow path (28) to the supply path (29) and the first flow path (27) ) fluidically separates from the feed path (29), - d the second valve (34) in the second position (40) fluidly connects the first flow path (27) to the return path (30) and fluidically separates the second flow path (28) from the return path (30), - that the control device (23) is designed in such a way that it moves the valves (33, 34) into the first position (36, 37) in the first operating mode (16) and into the second position (39, 40) in the second operating mode (17). Fuel cell system according to one of the Claims 3 to 5 Characterized in that - the switching device (20) in the switching section (26) comprises a drum (45) having a first chamber (50) and separate from the first chamber (50), second chamber (51), - that the first adsorption (12) is arranged in the first chamber (50) and the second adsorption device (13) is arranged in the second chamber (51), - that the drum (45) has an inlet (46) fluidly connected to the feed channel (24) and one with the feed path (29) fluidically connected feed connection (48) and a return connection (49) fluidically connected to the return path (30), - that the chambers (50, 51) between a first arrangement (52) and a second arrangement (53) are movable, - that in the first arrangement (52) the inlet (46) and the supply connection (48) are connected to the first chamber (50) and the return connection (48) are connected to the second chamber (51), - that in the second arrangement (53) the inlet (46) and the supply connection (48) are connected to the second chamber (51) and the return connection (49) are connected to the first chamber (50), - that the control device (23) is designed such that it has chambers (50, 51) in the first operating mode (16 ) moved into the first arrangement (52) and in the second operating mode (17) into the second arrangement (53). Fuel cell system according to one of the Claims 3 to 6th , characterized in that the return path (30) runs between a reactant removal point (41) in the supply path (29) and the switching section (26). Fuel cell system according to one of the Claims 3 to 7th , characterized in that the return path (30) runs between an exhaust gas extraction point (42) of the duct system (6) arranged downstream of the fuel cell (4) and the switching section (26). Fuel cell system according to Claim 7 or 8th , characterized in that the conveying device (7) is arranged in the channel system (6) in such a way that the respective extraction point (41, 42) is arranged on a pressure side (9) of the channel system (6) during operation. Fuel cell system according to one of the Claims 3 to 9 , characterized in that the fuel cell system (1) has a humidifying device (32) for humidifying the reactant, which is integrated upstream of the fuel cell (4) in the feed path (29). Fuel cell system according to one of the Claims 7 to 9 and Claim 10 , characterized in that the reactant removal point (42) is arranged upstream of the humidifying device (32). Fuel cell system according to Claim 8 or 9 and Claim 10 or 11 Characterized in that - the humidifying device (32) from the feeding path (29) of the fuel cell (4) downstream fluidly isolated in the duct system (6) is integrated in - that the exhaust gas sampling point (42) downstream of the moistening device (32) is arranged. Fuel cell system according to one of the Claims 3 to 12th , characterized in that in at least one of the operating modes (16, 17) the fluid for the regeneration of the associated adsorption device (12, 13) flows out of the channel system (6) via the switching device (20). Fuel cell system according to one of the Claims 1 to 13th , characterized in that the control device (23) is designed such that it changes between the first operating mode (16) and the second operating mode (17) at predetermined time intervals. Fuel cell system according to one of the Claims 1 to 14th , characterized in that - that the fuel cell system (1) has a sensor device (54) which is designed such that it determines the pollutant concentration in the duct system (6) during operation, - that the control device (23) communicates with the sensor device (54) is connected and designed in such a way that it determines the fuel cell system (1) depending on the Adjusted pollutant concentration between the first operating mode (16) and the second operating mode (17).

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