Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
  • H01M8/2465—Details of groupings of fuel cells
  • H01M8/247—Arrangements for tightening a stack, for accommodation of a stack in a tank or for assembling different tanks
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
  • H01M8/04067—Heat exchange or temperature measuring elements, thermal insulation, e.g. heat pipes, heat pumps, fins
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
  • H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
  • H01M8/065—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants by dissolution of metals or alloys; by dehydriding metallic substances
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
  • H01M8/2465—Details of groupings of fuel cells
  • H01M8/2484—Details of groupings of fuel cells characterised by external manifolds
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
  • H01M8/04201—Reactant storage and supply, e.g. means for feeding, pipes
  • H01M8/04216—Reactant storage and supply, e.g. means for feeding, pipes characterised by the choice for a specific material, e.g. carbon, hydride, absorbent
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells

Definitions

• the invention relates to an integration backplane for fuel cell modules and to a fuel cell system.
• the invention relates to an integration backplane for holding at least one pair of fuel cell modules.
• Modular fuel cell systems are known in the state of the art.
• DE 10 2010 028 961 A1 a modular fuel cell system with several fuel cell units connected to a common integration backplane is disclosed.
• the integration backplane comprises a media channel system for the supply and discharge of process gases and a cooling medium.
• the individual fuel cell modules can be attached to the integration backplane by means of quick couplings, e.g. snap connections.
• a disadvantage of the modular system presented in DE 10 2010 028 961 A1 is that all balance- of-plant components are distributed in the space around the modular fuel cell system. In the air system, this results in an inhomogeneous pressure drop across the system.
• WO 2012/150174 A1 shows a kit for a modular fuel cell device with identical module housings for different system components.
• oxidant supply modules and fuel cell modules are designed with the same dimensions so that they can be arranged at different locations in a system accommodating the modules, such as a vehicle.
• a disadvantage of the kit disclosed in WO 2012/150174 A1 is that each individual module requires its own cabling as well as its own media supply and discharge ducts with corresponding constructional expenditure.
• US 2005/0079397 A1 discloses a heating element for a fuel cell system comprising a hydrogen storage medium capable of absorbing and releasing hydrogen in a re- versible reaction, the medium having a hydrogenated state comprising metal hydride and a dehydrogenated state comprising metal or metal alloy.
• the heating element serves as a functional component in the fuel cell stack, e.g., for efficient start-up conditions of a fuel cell system of a vehicle.
• the heating element is provided incorporated into a terminal collector end plate of the stack, as independent heater plates disposed in the stack, or incorporated into a bipolar plate.
• the in-stack design of the hydrogen storage medium adds to fuel cell complexity drastically, leading to high loss on power density and increased electric resistance in the stack. Furthermore, the hydrogen supply of each compartment is very complex as it needs valves and control for each heating element.
• DE 103 17 123 A1 discloses a fuel cell comprising at least one electrode/electrolyte unit and a flow module for process gases and coolant.
• the fuel cell connects to an external metal hydride heating unit which comprises a hydride-forming material so that heat is produced to warm the fuel cell.
• An external metal hydride heating unit which comprises a hydride-forming material so that heat is produced to warm the fuel cell.
• a disadvantage of the system is that, albeit looking simple, the system requires complex control. Moreover, the thermal transfer has high losses due to the piping and a large amount of material would be necessary to compensate for the losses, resulting in high added mass to the system. The system is also difficult to integrate in a cooling cycle, as it requires complex heat transfer to the cooling fluid.
• an integration backplane for holding at least one pair of fuel cell modules.
• Each fuel cell module comprises at least one stack of fuel cells.
• the integration backplane is provided with a positioning means for the pair of fuel cell modules.
• the integration backplane is further provided with a media interface, which may also be referred to as Ml in the following.
• the media interface includes module connection ports for connecting to the fuel cell modules.
• the media interface is provided with fuel ducts for the routing of a fuel such as hydrogen to the fuel cell modules and an interface for the coupling with a fuel tank outlet such as a hydrogen tank outlet, and the media interface includes a heating unit capable of absorbing and releasing the fuel in a reversible reaction, the heating unit being connected to the fuel ducts and being connectable to the fuel cell modules.
• the integration backplane combines a solution for the media supply, a support for the modules and may at the same time house individual balance-of-plant components. Performance of the heating unit is especially efficient due to its close integration into the media interface.
• the heating unit is connectable with the fuel cell modules such that close thermal contact with the fuel cells may be established.
• the connection can be a direct connection, wherein the heating unit and the fuel cell modules are in direct thermal contact. In preferred embodiments, however, there is an indirect connection, wherein the fuel cell modules and the heating unit are coupled through a fluid and/or a solid body and/or other means of thermal transport.
• integration backplane comprises a coolant inlet and a coolant outlet and a first coolant manifold for the routing of a coolant to the fuel cell modules, the heating unit being in thermal contact with the first cooling manifold.
• the heating unit can be used also as thermal moderator (absorbing and desorbing heat) that utilizes the heating as well as the cooling capacity of the metal hydride, increasing thus the stability of the temperature in the system without affecting the actual heat dissipating system.
• the media interface comprises one or more heat pipes and heat pipe connection ports to the fuel cell modules, the heating unit being in thermal contact with the heat pipe.
• the heat pipe is a heat-transfer device that combines the principles of both thermal conductivity and phase transition to effectively transfer heat between two solid interfaces. Details and different embodi- ments of heat pipes are known to the skilled person.
• the heating unit is thus connected to heat pipes to transfer heat to the fuel cell stack(s). This results in a small stack complexity and allows the change of fuel cell modules without impacting the heating unit. Furthermore, a fast and effective heat transfer to the fuel cell stacks can be realized with heat pipes.
• the medium capable of absorbing and releasing the fuel in a reversible reaction may comprise a metal hydride.
• the metal hydride generates heat by absorption of hydrogen and absorbs heat by releasing hydrogen.
• Possible metal hydride materials may be based on intermetallic compounds such as alloys of TiMn 2 , FeTi, LaNi 5 , TiCr, TiV, TiZr etc.
• the invention is not limited by the cited materials and further suitable materials are known to the skilled person.
• the materials cited in US 2005/0079397 A1 and DE 103 17 123 A1 are also incorporated by reference.
• the use of metal hydride in the heating unit allows for passive controlling of temperature in the system, requiring at most one or several valves as additional components, as will be outlined below.
• the metal hydride allows for the provision of high heating power and high heat density, as compared to conventional heating systems. Furthermore, no external energy source is needed for the heating unit. Additionally, metal hydride is functional at any low temperature.
• the metal hydride preferably has a defined porosity or defined compaction and enhanced intrinsic thermal conductivity.
• the metal hydride may be in the form of a composite material and may be provided with enhancing structures.
• thermodynamic properties of the metal hydride are tuned to meet the inlet pressure of the fuel cell system in that at a defined low temperature, e.g., at a temperature below 0°C, or from -40°C and 0°C, or from -30°C and -10°C, or around -20°C, the inlet pressure of the fuel cell system is sufficient to allow a complete hydrogenation of the material.
• the thermodynamic properties may be adjusted such that heat will be released if the metal hydride is hydrogenated at this low temperature.
• a fast and efficient heat transfer between the heating unit and the fuel cell modules allows for fast thermal responses in order to realize, e.g., a fast start-up, freeze start, regulated shutdown etc. of the system.
• the start-up of the fuel cell system is improved.
• the start-up of the fuel cell system is dependent on the increase of temperature in terms of reaching high efficiency and performance.
• the heat release from the metal hydride can be used to rapidly warm the stack(s). A more rapidly warmed stack allows a faster time to >90% power which is ideal or desired in most applications.
• freeze start of the fuel cell system is improved.
• a freeze start of a fuel cell system is complicated due to ice formation which prevents a delivery of full power until the stack reaches a critical temperature threshold.
• the metal hydride can be used to release heat with a faster discharge than liquid coolant, thus providing a shorter time to full power and to minimal operating temperature of the fuel cell modules.
• the heating unit does not consume any extra energy, thereby reducing the parasitic load to the system.
• the shutdown of a fuel cell system is also improved.
• Shutdown is temperature sensitive since efficiency decreases as the stack is cooled. Effective heat output can increase placing demands on the conventional cooling system designs which are dynamically slow.
• the metal hydride can be used as a heat sink for the additional energy released during shutdown and provides faster thermal dynamics to manage temperature spikes.
• the fuel cell stack temperature will increase to an operating level at which the thermodynamics of the metal hydride will be in favor of its dehydrogenation.
• the thermodynamic properties of the metal hydride is additionally adjusted such that at a defined operating temperature, e.g., at a temperature between 40°C and 90°C, preferably at a temperature between 50°C and 80°C, more preferably at around 70°C, the inlet pressure of the fuel cell system is sufficient to allow a partial, or even massive, dehydrogenation of the material. That way the initially spent fuel may be refed to the system for consumption and the metal hydride may be prepared for a new start-up.
• the heating unit comprising the metal hydride may act as a moderating device, wherein moderating shall occur at the operating temperature of the fuel cell system. If the temperature increases the metal hydride switches to desorbing and acts as a heat sink. If the temperature decreases, the metal hydride switches to absorbing and acts as a heat source.
• thermodynamic properties of the metal hydride are adjusted that moderating at operating temperature is achieved precisely at the system’s fuel inlet pressure.
• controlled valves are used to adjust the pressure in the heating unit such that moderating at operating temperature can be achieved.
• Adjusting the thermodynamic properties may include choosing the specific material and the amount of material, i.e., the mass of the metal hydride.
• the materials composition in alloys is adjusted, e.g., TiMn 2 can be tuned by Zr to form (Ti 1.x Zr x )Mn 2 with large impact on plateau pressure.
• geometry and size of the heating unit is chosen, wherein size will mostly affect the total energy of the heating unit and geometry will mostly affect the power and speed of heat release.
• the amount of metal hydride is chosen according to fulfil the required heating up performance, referring to the required temperature raise, the mass to be heated, the speed of heating, available pressure etc. Heating up of, e.g., 1 ,7 kg of graphite by 20 K may be performed with 100 g of metal hydride, assuming that about 30 kJ/mol-H 2 during absorption is released which corresponds to ca. 70 mWh/g of metal hydride. For a typical fuel cell stack of about 20 kg weight, ca. 600 g of metal hydride may be used for a quick temperature rise of 10 K.
• the mass of the metal hydride is adjusted to the total mass to be heated.
• the media interface includes first air passages for the routing of air, typically external air to an air module, module connecting air passages for the routing of compressed air from the air module to the fuel cell modules, and evacuation air passages for the evacuation of depleted air from the fuel cell modules.
• the integration backplane thus advantageously combines a solution for the air supply, a support for the modules and at the same time houses the heating unit.
• an air module is arranged inside the Ml or external to the Ml.
• the positioning means is adapted for holding at least one air module.
• the media interface includes module connection ports for connecting to the air modules.
• the air module can be arranged in a symmetric position with regards to the fuel cell modules of the pair of fuel cell modules.
• the air module is not necessarily of the same size as the fuel cell modules. Preferred embodiments of the invention thus provide for the optimization of the airflow and achieve a low pressure drop between the compressor of the air module and the fuel cell stack of the fuel cell module.
• the air module can in some embodiments be arranged between the fuel cell modules of the pair of fuel cell modules.
• the symmetric position of the air module with respect to the fuel cell modules has the advantage that no balancing means needs to be provided to compensate for asymmetrical piping and, thus, pressure inhomogeneity.
• the position between the fuel cell modules allows for less piping and low pressure loss between the compressor and the fuel cell stacks.
• the design of the air module as a connectable module allows its replacement when it is out of service.
• the air module can be easily dismantled and cleaned, for example for service and maintenance purposes.
• each fuel cell module can be easily replaced in the event of error messages.
• the media interface can include further balance-of-plant (BOP) components.
• BOP balance-of-plant
• Each balance-of-plant component located in the media interface is advantageously EMC- shielded and protected against dust and water ingress.
• the media interface can, for example, be manufactured in accordance with protection class IP67 or IP6K6K. Protection class IP67 is understood according to DIN EN 60529 (VDE 0470-1 ):2014-09. Protection class IP6K is understood according to ISO 20653:2013.
• the housing of balance-of-plant components in the Ml has the additional advantage that the costs for extra housing or enclosure of the respective BOP component can be saved.
• Balance-of-plant components installed in the media interface can be, in particular: humidifier, air filter, intercooler and valves from the cathode subsystem, heat exchanger, cooling pump, filter, valves and ion exchangers from the cooling circuit subsystem, and water separator, compressor, heat exchanger, valves such as, in particular, the purge valve and injector valve from the anode subsystem.
• the media interface provides a housing for at least one humidifier.
• the module connecting air passages comprise second air passages for the routing of compressed air from the air module to the humidifier and third air passages for the routing of humidified compressed air to the fuel cell modules.
• the evacuation air passages comprise fourth air passages for the routing of depleted wet air from the fuel cell modules to the humidifier and fifth air passages for the evacuation of excess air from the humidifier.
• the humidifier does not have to be located in the air module itself.
• the so-called cathode path or air path, or air loop, respectively, is divided into one part in the air module and a second part in the integration backplane. Since the humidifier is located in the integration backplane, components such as the compressor and intercooler are arranged in the air module. Alternatively, the intercooler can also be located in the integration backplane.
• the humidifier draws the moisture from the depleted and humidified air from the air outlet of the fuel cell module and adds it to the moisture from the fresh air drawn in externally. Examples of humidifier are well known to the person skilled in the art.
• the humidifier is arranged between the positions for the fuel cell modules and facing the position of the air module. It is considered as an advantage to position the humidifier opposite the air module. This arrangement results in lower pressure loss between the compressor and the fuel cell stacks.
• At least the second air passages, the third air passages, the fourth air passages and the fifth air passages are symmetrical with respect to the positions of the fuel cell modules.
• the first air passages are symmetrical with respect to the positions of the fuel cell modules.
• At least one of the air passages of the media interface is shaped to provide silencer functions.
• the air passages may be equipped with bending sections to counteract the formation of standing waves in straight sections.
• the advantage here is a reduction in noise development. This means that the air route is as small as possible and the air channels are designed in such a way that fewer standing waves or standing waves of smaller amplitudes are formed, and thus less resonance and noise will be generated.
• the media interface comprises external media connection ports.
• the external media connection ports may include a coolant inlet, a coolant outlet, an air inlet, an air outlet and a fuel inlet.
• the arrangement of the external media connection ports in the media interface allows an adaptive extension of the integration backplane especially onto similar, identically designed integration backplanes, and thus a scalability of the system from 2 to 4 to 6 and, in principle, any number of fuel cell modules.
• the media interface includes connection means for the current collection of the fuel cell modules.
• the connection means may be arranged at the same side or on different sides as the module connection ports.
• the integration backplane may be provided with a mount which includes power electronics.
• the power electronics may be suitable for the operation of one or several compressors.
• the power may be used for the operation of a compressor of the air module.
• the mount may include a power conversion device, such as a DC/AC or DC/DC converter or an inverter.
• the conversion device may be connectable to current collection means of the fuel cell modules either individually or via a common rail.
• the mount may include at least one fuel cell control unit for monitoring at least one operation parameter of the fuel cell modules.
• operation parameters may include cell voltages, cell currents, cell temperatures, cell resistances, module voltages, module currents, module temperatures, module resistances, or the like.
• the fuel cell modules may include fuel cell control units for monitoring the operation parameters.
• the mount may be arranged opposite the modules. This makes it possible to connect the DC/AC or DC/DC converter or inverter and/or fuel cell control units to the cell modules with minimal voltage losses.
• the media interface includes coolant manifolds for the routing of a coolant to and from the fuel cell modules.
• the media interface provides a housing for a system bypass valve which can be controlled such that each fuel cell module can be selectively activated or deactivated, or such that the pair of fuel cell modules can be deactivated.
• the system bypass may in some embodiments include a flow bypass to avert flow within the module when deactivated, such that the overall performance and durability of each module can be maximized.
• Further integrated controllers within the media interface can be configured to load balance amongst the modules.
• a fuel cell system having the integration backplane described above is proposed.
• the fuel cell system has at least two fuel cell modules arranged on the positioning means and connected to the media interface.
• the fuel cell system has at least one air module arranged on the positioning means and connected to the media interface.
• the fuel cell system has exactly two fuel cell modules and exactly one air module arranged on the positioning means and connected to the media interface.
• Module connection is provided, for example, by mechanical connections for the assembly, gas connections, electrical connections, and data communication connections. All connections may be such that the modules are interchangeable even for non-experts. In particular, quick-locking and quick-release systems may be provided.
• the module connections of the media interface can, for example, be manufactured such that the fuel cell system including the integration backplane and the connected modules is in accordance with protection class IP67 or IP6K6K.
• all connections may comprise sealing or sealing means on faces, edges or perimeters to allow for intrusion protection, e.g. against dust, wind, water etc.
• the mechanical connections may include, in particular, bayonet couplings, plug-in snap-in couplings or similar.
• screws may be provided for connecting the modules to the media interface, which are inserted from the back of the modules and run through the entire module and are screwed into the media interface.
• gas connections preferred form-fit connecting means are provided, especially self-sealing connections.
• Electrical connections are preferably plug connections. All gas and electrical connections may include sealing or sealing means for intrusion protection and leak tightness, in particular the sealing may include face, edge, and/or perimeter sealings.
• the air module comprises at least one compressor.
• compressors typically, but not limiting, fans, screw compressors, turbo compressors, roots compressors or radial compressors may be used as compressor.
• the air module comprises an intercooler.
• the intercooler cools down the air heated by compression from the compressor to the operating conditions of the fuel cell stack.
• the media interface or the positioning means may include mounting points for integration into a vehicle chassis.
• the fuel cell modules are of a lunchbox-type and of identical outer dimensions.
• a fuel cell module having an enclosure with a progressive locking system may also be called “lunchbox” enclosure.
• Such a fuel cell module may have a plurality of fuel cells forming a fuel cell stack.
• the fuel cell module may include an enclosure which surrounds the fuel cell stack.
• the enclosure may include a bottom assembly and a lid cap assembly.
• the bottom assembly and lid cap assembly may be provided with a progressive locking system providing a range of compression pressures to the fuel cell module.
• the bottom assembly may include a jacket which is at least partly form-fitted to the stack architecture providing internal alignment functions and a bottom plate in pressure contact with the fuel cell stack.
• the lid cap assembly may comprise a compression plate in pressure contact with the fuel cell stack.
• the lid cap assembly may comprise media routing elements.
• the fuel cell stacks or the fuel cells may be provided with additional heating units.
• the addi- tional heating units may comprise metal hydride, as described above.
• the metal hydride may be used for generating heat at low temperatures, as described above.
• the thermodynamic properties of the metal hydride may be adjusted such that the required behavior is passively controlled by the actual temperature of the stack.
• the fuel cell stacks or the fuel cells may comprise circumferential additional heating units.
• the additional heating units may be positioned on the circumference of the fuel cell stack or fuel cells, either continuously or at given specific locations. That way a high area contact can be achieved, and heat transfer is increased which results in a very dynamic system.
• the positions of the additional heating units are chosen to increase heating effect, e.g., close to cooling channels.
• additional heating units may be integrated into the fuel cell stack.
• the additional heating units can be, e.g., one tube or several tubes located in the fuel cell stack with beneficial thermal connections to other components such as cooling channels, bipolar plates etc.
• the fuel cells may comprise internal additional heating units.
• the fuel cells may comprise internal additional heating units.
• almost all heat can only be dissipated in radial direction and is therefore preferably used to heat the fuel cells, allowing for low heat losses.
• This effect is further promoted by the high effective thermal conductivity of the fuel cell in radial direction due to stacked cells with higher thermal conductivity in-plane which is even more pronounced with graphitic bipolar plates.
• smallest amounts of metal hydride may be introduced to heat up very efficiently only the necessary thermal masses.
• Figure 1 is a pressure concentration temperature diagram for a metal hydride material.
• Figure 2 is a schematic representation of a fuel cell system according to an embodiment of the invention.
• Figure 3 is a schematic representation of a fuel cell system according to another embodiment of the invention.
• Figure 4 is a perspective view of a fuel cell system according to an embodiment of the invention.
• Figure 5 is a perspective view of a fuel cell system according to another embodiment of the invention.
• Figure 6 is another perspective view of the fuel cell system of Figure 5.
• Figure 7 is a rear side view of the fuel cell system of Figure 5.
• Figure 8 is a side view of the fuel cell system of Figure 5.
• Figure 9 is another side view of the fuel cell system of Figure 5.
• Figure 10 is a front side view of the fuel cell system in Figure 5 without the fuel cell modules.
• Figure 11 is a perspective view of the integration backplane of Figure 5 without the fuel cell modules and without the air module.
• Figure 12 is a perspective view of the inside of the Ml of the fuel cell system of Figure 5.
• Figure 13 is another perspective view of the inside of the Ml of the fuel cell system of Figure 5.
• Figure 14 is a perspective view of the air module of the integration backplane of Figure 5.
• Figure 15 is a side view of the air module of Figure 14 with the housing open.
• Figure 16 is a perspective view of the air module of Figure 14 with the housing open. DESCRIPTION OF THE DRAWINGS
• Figure 1 shows the behavior of a metal hydride material according to the invention in different ambient temperature settings.
• Figure 1 depicts the equilibrium pressures at different ambient temperatures as a function of hydrogen stored in the metal hydride. Four curves are shown, wherein two curves show the absorption and desorption of hydrogen at 0°C and two curves show the absorption and desorption of hydrogen at -20°C.
• the material shows a hysteresis.
• the desorption curves are more flattened, i.e., they show a more pronounced plateau than the absorption curves and there is a distinct pressure difference between absorption and desorption equilibrium conditions.
• the complex pressure concentration temperature behavior of the metal hydride is advantageously used in the context of the present invention.
• the thermodynamic properties are such that heat will be released if the metal hydride is hydrogenated at low temperature and inlet pressure of the fuel cell system. If, as depicted, inlet pressure is at 3 bar and ambient temperature is -20°C, the metal hydride absorbs hydrogen until it reaches a concentration of about 1 ,6 wt.%. Therefore, the inlet pressure of the fuel cell system is sufficient to allow a complete hydrogenation of the material.
• One may, e.g., define the start of the second convex section as the state of complete hydrogenation. The heat produced by the exothermic reaction during absorption of hydrogen is transported to the fuel cell modules for the freeze start of the system.
• the metal hydride will automatically release a part of the stored hydrogen.
• This process happens automatically and thus is passive in terms of controls. Moderating behavior can simply be achieved if the pressure, e.g., controlled by valves, and the operating temperature in the system are such that the concentration level is on the plateau. If the temperature increases the metal hydride switches to desorbing and acts as a heat sink while consuming hydrogen. If the temperature decreases, the metal hydride switches to absorbing and acts as a heat source while releasing hydrogen.
• FIG 2 is a schematic representation of a fuel cell system 100 according to an embodiment of the invention.
• the fuel cell system 100 comprises two fuel cell modules 110 connected to an integration backplane 10.
• the integration backplane 10 may be shaped and configured as described in more detail below with regards to the embodiments depicted in Figs. 4 ff.
• Fig. 2 shows the heating unit 102 which is housed in the integration backplane (more precisely, in the Ml 20, as described below) and connected to the fuel duct 72 which also connect to the fuel cell modules 110. Via fuel duct 72, fuel can enter or leave the heating unit 102, depending on whether the metal hydride contained therein is in a state of absorbing or releasing hydrogen, as outlined above. Furthermore, the heating unit 102 is connected to a first coolant manifold 70 for providing heat to the fuel cell stacks contained in the fuel cell modules 110, e.g., for the start-up of the system, or for acting as a heat sink.
• a first coolant manifold 70 for providing heat to the fuel cell stacks contained in the fuel cell modules 110, e.g., for the start-up of the system, or for acting as a heat sink.
• FIG 3 is a schematic representation of a fuel cell system 100 according to another embodiment of the invention.
• this fuel cell system 100 exemplary, comprises two fuel cell modules 1 10 connected to integration backplane 10.
• Heating unit 102 is housed in the integration backplane and connected to the fuel duct 72 which also connect to the fuel cell modules 110.
• fuel duct 72 fuel can enter or leave the heating unit 102, depending on whether the metal hydride contained therein is in a state of absorbing or releasing hydrogen.
• the transport of the heat from heating unit 102 to the fuel cell modules 110 happens through heat pipes 104.
• integration backplane 10 comprises a heat pipe 104 and a heat pipe connection port for the fuel cell modules 110.
• the fuel cell modules 110 may also be provided with heat pipes to facilitate quick and efficient transport of the heat to the fuel cells for start-up, or to remove heat from the fuel cells, e.g., during shutdown.
• the heating unit 102 is in thermal contact with the heat pipe 104.
• Figure 4 is a perspective view of a fuel cell system 100 according to an embodiment of the invention.
• Figure 5 is a perspective view of the fuel cell system 100 according to another embodiment of the invention.
• an air module (not depicted) can be arranged inside the Ml 20 or external to the Ml 20.
• an air module 120 is arranged between the fuel cell modules 110 on the positioning means 12.
• Figures 6 to 9 show different perspectives of the fuel cell system 100 according to the embodiment of Figure 5.
• Figures 10 and 11 show how the fuel cell modules 110 and the air module 120 are connected to the integration backplane 10 in this embodiment.
• Figures 12 and 13 show the interior of the media interface (Ml) 20 in this embodiment, with the housing of the Ml 20 omitted for ease of understanding.
• Figures 14 to 16 show the air module 120 in this embodiment.
• both embodiments depicted in Figs. 4 and 5 can comprise several similar mounting parts or elements, the description of same or similar features is not repeated.
• the fuel cell system 100 comprises an integration backplane 10 with a positioning means 12 and a Ml 20 arranged approximately in an L-shape relative to each other. It is advantageous if the positioning means 12 is manufactured in one piece with the Ml 20, e.g., integrally formed by molding, casting, 3D printing or the like.
• Figs. 4 and 5 show the Ml 20 with external media connection ports 24, where in perspective a coolant inlet 40, a coolant outlet 42, an air inlet 44 and a fuel inlet 48 can be seen.
• a mount 30 is attached to the Ml 20.
• the mount 30 typically comprises electronic assemblies, in particular DC/AC or DC/DC converters or inverters, power electronics and fuel cell controllers. Electrical lines and data lines from the fuel cell modules 110 to the mount 30 may run through the Ml 20. Corresponding cable openings may be provided in both the Ml 20 and the mount 30 (not shown).
• the Ml 20 is thus located between the mount 30 and the fuel cell modules 110.
• the mount 30 has essentially identical outer dimensions to the Ml 20 in directions d! and d 3 , which is best visible in Figure 6.
• the essentially cubic outline makes the fuel cell system 100 very compact in its dimensions and particularly suitable for the integration into mobile systems such as vehicles.
• the mount 30 is fixed by means of a plurality of fixation means 32, which are arranged in wall recesses 34 of the mount 30.
• the way the mount 30 is fixed to the Ml 20 can be done in different ways, for example by bolting, welding, riveting or the like.
• the fixation means 32 are advantageously accessible from a direction perpendicular to the main dimension of the mount 30, i.e. d 2 .
• the illustrated mount 30 allows the mount 30 to be removed at the location of the fuel cell system 100, so that the electronic assemblies contained in the mount 30 can be replaced in case of damage.
• a control bus connection port 36 and AV terminals 38 are located on the same side as some of the external media connection ports 24.
• On the side of the control bus connection port 36 by way of example, as can be seen in Figure 6, there is an air inlet 44 and an air outlet 46, which are also external media connection ports 24.
• FIGs 4 and 5 further show the fuel inlet 48, with a fuel channel inside the Ml 20.
• Another access window 25 is located approximately in the middle of the mounting 30, but slightly offset, to connect the hydrogen duct to the second fuel cell module 110.
• the access windows 25 are not symmetrical in relation to the Ml 20, which is not limiting to the invention.
• the fuel duct 72 may be in the form of a pipe and is usually made of metal.
• the fuel supply represents a safety-relevant aspect of the system. In order to ensure a leak-proof supply and to check the leakage, direct access to the fuel inlets 48 via access windows 25 is thus advantageous.
• the connection to the fuel cell module 110 can be made via a fitting 49 (depicted in Fig. 9).
• three fuel cell modules 110 are arranged on the positioning means 12.
• the exemplary embodiment presented explicitly shows three fuel cell modules 110 arranged adjacent to each other, the invention is not limited to this.
• the Ml 20 according to the invention can be designed to accommodate a larger number of fuel cell modules 110.
• Figure 5 shows two fuel cell modules 110, i.e., one pair of fuel cell modules 110, and an air module 120, arranged on the positioning means 12.
• the air module 120 is arranged adjacent to each individual fuel cell module 110. In the embodiment shown, the air module 120 is located in the middle, i.e., between the fuel cell modules 110, but this is not restrictive of the invention.
• the exemplary embodiment presented explicitly shows two fuel cell modules 110 and one air module 120 arranged in between, the invention is not limited to this.
• the Ml 20 according to the invention can be designed to accommodate a larger number of pairs of fuel cell modules 110 and air modules 120 arranged adjacent to each other. It has been shown that with quite similar external dimensions of the air module 120 and the fuel cell modules 110, a sufficient supply of compressed cooled air to the stacks can be achieved.
• Figure 6 shows a perspective view of the fuel cell system 100 of Figure 5 from an opposite direction.
• the fuel cell modules 110 and the air module 120 can be seen from the rear side, which corresponds to their bottom sides during assembly.
• the fuel cell modules 110 and the air module 120 are arranged side by side on the positioning means 12 as described with reference to Figure 5.
• the positioning means 12 fits with the size of the modules 110, 120 and ends flush with them.
• the fuel cell modules 110 are designed as so-called lunchbox-type modules in the exemplary embodiments shown, without, however, restricting the invention.
• the lunchbox-type modules comprise a bottom assembly 114 nested in a lid cap assembly 112. Between the bottom assembly 114 and the lid cap assembly 112 there are pockets 116 arranged on each of the two long sides of the stack footprint, in which a progressive fixation system can be placed.
• the progressive fixation system provides for a variable range of compression pressures to the fuel cell stack located in the fuel cell module 110.
• the invention is not limited to the various embodiments of the fuel cell stack.
• the fuel cell stack may comprise a sequence of bipolar plates, MEAs and GDLs, limited by top and bottom end plates for current collection. Alternatively, monopolar plates can be used.
• the so-called stack direction corresponds to direction d 2 .
• the individual bipolar plates are arranged vertically in the drawing plane and run essentially parallel to the main dimensions d 3 and di of the Ml 20.
• this arrangement makes advantageous use of the gravitational effect on the molecules participating in the chemical reaction, e.g. water droplets passing through the fluid channels of the bipolar plates. The water droplets will tend to fall to their outlet, which is the air outlet 46 in most embodiments.
• Mounting points 54 are located in the area of the bottom assembly 114 of the fuel cell module 110, whereby four mounting points 54 per fuel cell module 110 are provided here as an example, but not as a limitation to the invention. Two of the mounting points 54 are located in the corners of the bottom assembly 114, and two more of the mounting points 54 are located, by way of example, in the area of the pockets 116 of the fuel cell modules 110. Of course, various other arrangements can be there, in particular arrangements involving more or less than four mounting points 54.
• Figure 7 shows a top view of the integration backplane 10 with mount 30 in the foreground. There is a large recess 34 in mount 30 for the access window 25 to the fuel inlet 48 in its lower area. On the bottom side, stiffening ribs 14 are arranged, which run along the positioning means 12.
• the stiffening ribs 14 are designed to absorb shocks and vibrations. They serve to stiffen the integration backplane 10 and protect the fuel cell modules 110 from mechanical shocks.
• the side view of fuel cell system 100 shows that the stiffening ribs 14 do not protrude evenly over the length I of positioning means 12, but may be shaped like a wedge heel 18.
• the wedge heel 18 represents only one possible embodiment of the layout of the underside of the integration backplane 10.
• the embodiment shown simply has the advantage that the fuel cell modules 110 are operated in a slightly inclined position, which may improve the flow of media such as air and fuel through the fuel cell stack.
• the stiffening ribs 14 may run evenly.
• the fuel cell modules 110 can be operated essentially horizontally, and the fuel stacks can be operated with vertical alignment of the bipolar plates.
• the orientation of the stack can be adapted such that the orientation of the individual fuel cell modules 110 can be adjusted such that the most desirable orientation with the direction of the force of gravity is achieved.
• Figure 8 also shows that the Ml 20 has essentially the same height h as the modules 110, 120, so that, fearing the wedge heel 18, an essentially cuboid-shaped overall external outline of the fuel cell system 100 is achieved.
• Figure 10 shows a front view of the fuel cell system 100 as described with reference to the previous figures.
• the two fuel cell modules 110 are not shown, only the air module 120 is arranged on the positioning means 12.
• the module connection ports 22 are identical for each of the fuel cell modules 110. Thus, they allow identical fuel cell modules 110 to be connected.
• An area for the module connection port 22 for one of the modules 110, 120 is represented by reference sign 23.
• the specific positions of the connection ports 22 is not limiting the invention.
• the module connection ports 22 comprise a coolant inlet 40 and a coolant outlet 42, which are provided at diametrically opposite corners of the respective region of the module connection area 23.
• the module connection ports 22 further comprise an air inlet 44 and an air outlet 46, which are also located on opposite sides of the region of the module connection area 23.
• connection means 52 Centrally located in the module connection area 23, there are connection means 52 for connection to the corresponding current collectors provided at the fuel cell modules 110.
• the connection means 52 can also be used to operate or control sensors which may be present in the modules 110, 120.
• the module connection ports 22 further include the fuel outlet 50.
• a control bus connection port 36 is provided for data lines and sensor lines. Via control bus connection port 36 data and sensor signals from the modules 110, 120 may be transmitted to the corresponding control buses or control devices in mount 30.
• Two mounting points 54 are provided for each fuel cell module 110, which are arranged diametrically opposite each other, enabling the fuel cell module 110 to be attached quickly and easily to the Ml 20.
• the air module 120 has also been removed so that the module connection ports 22 for the air module 120 are visible.
• the module connection ports 22 for the air module 120 include an air outlet 46 and an air inlet 44, which are located at the same distance from the footprint areas 13 of the fuel cell modules 110.
• an intercooler 126 is provided in the air module 120, see Figs. 16 to 18.
• the module connection ports 22 for the air module 120 include a coolant inlet 40 and a coolant outlet 42 which are to be connected to the intercooler 126 in the air module 120.
• connection means 52 provides the power supply.
• the connection means 52 can also be used to operate or control sensors which may be present in the air module 120.
• the positioning means 12 is also more clearly visible, as modules 110, 120 are not shown.
• the positioning means 12 comprises the footprint areas 13 for the modules 110, 120, with the footprint areas 13 being limited by guide rails 16.
• the guide rails provide a positioning aid for the module connection ports 22.
• the footprint areas 13 are directly limited by the Ml 20.
• the footprint areas 13 are seamless. In this way, modules 110, 120 can be easily connected or disconnected individually to/from the integration backplane 10.
• Figure 12 shows the interior of the Ml 20, in particular to indicate some media manifold channels 27 and the heating unit 102 in connection with the invention.
• the media manifold channels 27 include coolant manifolds 70, 70a and an air manifold 80.
• a first coolant manifold 70 is provided in the lower part of the Ml 20 and a second coolant manifold 70a in the upper part of the Ml 20.
• the coolant manifolds 70, 70a have coolant inlets 40 and coolant outlets 42 on the side of the Ml 20, which have already been described with reference to the previous figures.
• coolant outlets 42 and coolant inlets 40 for the individual fuel cell modules 110 branch off from coolant manifolds 70, 70a.
• another coolant inlet 40 and another coolant outlet 42 can be placed in the middle of the Ml 20 for supplying the intercooler 126 in the air module 120 with coolant.
• the air manifold 80 is located between the coolant manifolds 70, 70a.
• the air manifold 80 comprises the air inlet 44 and air outlet 46 already described with reference to the previous figures.
• the air manifold 80 comprises two air inlets 44 on both sides of the Ml 20. This reduces the noise level and allows air manifold 80 with a smaller diameter to be used.
• the air manifold 80 is essentially T-shaped, with the air outlet 46 lower than the two air inlets 44, which is sometimes also referred to as a through.
• the two air inlets 44 are provided at the same height. This specific air routing prevents the build-up of standing waves in the air manifold 80 and prevents or, at least, reduces noise.
• the air outlet 46 is thus provided in the central area of the Ml 20 for connection to the air module 120, and an air inlet 44 is provided to supply the compressed air provided by the air module 120 to a humidifier 26.
• the humidifier 26 is located in the middle of the Ml 20 between the positions for the fuel cell modules 110 and opposite the position of the air module 120. From the humidifier 26, the wet compressed air is guided to the fuel cell modules 110.
• air outlets 46 and air inlets 44 are arranged symmetrically to one another, in particular mirror-symmetrically with respect to a longitudinal axis through the Ml 20, the longitudinal axis being shown in Figure 6 as axis d,.
• figures 12 and 13 show air passages 60, 62, 64, 66, 68 through the Ml 20.
• a first air passage 60 runs from the air inlet 44 of the air manifold 80 to the air outlet 46 for connection to the air module 120.
• the compressed air from the air module 120 is fed through the air inlet 44 via the second air passage 62 to the humidifier 26, as can be seen especially well in Figure 13.
• the compressed wet air is fed via a third air passage 64 to the air outlets 46 for connection to the fuel cell modules 110.
• the airflow is divided by an airflow divider 82.
• the depleted wet air from the fuel cell modules 110 is returned to the humidifier 26 via fourth air passages 66, where it meets the external air and can be humidified additionally.
• a fifth air passage 68 the excess air from the humidifier 26 is discharged from the Ml 20 at another air outlet 46.
• the return of excess air takes place only in one lateral direction, which is, however, not restrictive for the invention.
• a symmetrical air discharge can of course be provided.
• the air module 120 is positioned between the pair of fuel cell modules 110. Since the air module 120 is located between the two fuel cell modules 110, the duct lengths for air passages 60, 62, 64, 66, 68 are ideally short. This allows a very low pressure drop of the air generated by the compressor 124 of the air module 120 over the Ml 20 and integration backplane 10.
• the air module 120 has a smaller width than the fuel cell modules 110.
• the width is thus explicitly deviated from the module dimension, so that the fuel cell modules 110 and the air module 120 are not interchangeable.
• These dimensions may be optimized by the skilled person so that the shortest possible duct length can be obtained for air passages 60, 62, 64, 66, 68.
• the duct lengths for air passages 60, 62, 64, 66, 68 are ideally short. This also contributes to the very low pressure drop of the air generated by the compres ln Figure 13, it is also visible that the fourth air passage 66 for the discharge of the depleted air from the fuel cell modules 110 to the humidifier 26 comprises a first bending section 84, followed by a flow cross-section change section 88, and followed by a second bending section 86.
• the first bending section 84 is essentially L-shaped and deflects the depleted air of the fuel cell modules 110 by 90 degrees. In the second bending section 86, the airflow is further deflected by 90 degrees towards the humidifier 26, which is located centrally in the Ml 20.
• a tapered component is provided for this purpose, which is not restrictively referred to as flow cross-section change section 88.
• bends or throughs can be provided in all air passages 60, 62, 64, 66, 68 so that straight, uncovered airflow channels are not used. This reduces the formation of standing waves and the associated disturbing noise.
• Figure 13 shows a system bypass valve 28 as a further element from the balance-of-plant.
• a system bypass valve 28 as a further element from the balance-of-plant.
• other balance-of-plant components from the anode path, from the cathode path and from the cooling circuit may be provided.
• Fig. 12 also shows the heating unit 102 arranged below the first air manifold 70 in the Ml 20.
• Fig. 13 one can see the connection of the heating unit 102 to the fuel duct 72 via tee connector 106.
• the heating unit 102 is connected to a first coolant manifold 70, e.g., close to the air outlets 24, for providing heat to the fuel cell stacks contained in the fuel cell modules 110, e.g., for the start-up of the system, or for acting as a heat sink.
• the heating unit 102 is shaped essentially block-like and has cuboid form which is, however, merely exemplary. Size, geometry and position in the backplane 10 of the heating unit 102 depends on the chosen material and the stack sizes, as well as on the energy needed.
• FIG 14 shows an exemplary embodiment of the air module 120 in perspective view.
• the housing 122 of the air module 120 is correspondingly cuboidal.
• the air module 120 may thus be suitably accommodated in the integration backplane 10 by the positioning means 12 pro- vided by the invention.
• the module connection ports 22 of the air module 120 are compatible with the respective module connection ports 22 of the Ml 20.
• Figure 14 to 16 provides for the coolant inlet 40 and coolant outlet 42 to be split up for the individual components in the air module 120.
• Figure 14 and Figure 11 refer to different embodiments as will readily be understood by the person skilled in the art. The invention is, however, not limited to these embodiments.
• Figures 15 and 16 show that the air module 120 includes a compressor 124, an intercooler 126 and a power electronics assembly 128.
• a first coolant inlet 40 and a first coolant outlet 42 are provided, which are located in the middle area of the front side of the air module 120 in Figure 14.
• a second coolant inlet 40 and a second coolant outlet 42 are provided in the corner areas of the air module 120.
• the coolant is supplied via a coolant passage 130 inside the housing 122 to the intercooler 126 and via a further coolant passage 130 to the coolant outlet 42.
• media manifold system bypass valve mount fixation means wall recess control bus connection port HV terminal coolant inlet coolant outlet air inlet air outlet fuel inlet fitting fuel outlet connection means mounting point -68 air passages first coolant manifold a second coolant manifold fuel duct air manifold airstream divider , 86 bending sections flow cross-section change section0 fuel cell system 2 heating unit 4 heat pipe 6 tee connector 0 fuel cell module 2 lid cap assembly 4 bottom assembly 6 pocket 0 air module 2 housing 4 compressor Intercooler power / electronics assembly coolant passage , 134 air passages

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• 2022
  • 2022-01-14 EP EP22709176.6A patent/EP4238158A1/de active Pending
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