MXPA00006397A

MXPA00006397A - Fuel cell unit

Info

Publication number: MXPA00006397A
Application number: MXPA/A/2000/006397A
Authority: MX
Inventors: Klaus Rennebeck
Original assignee: Klaus Rennebeck
Priority date: 1997-12-28
Filing date: 2000-06-27
Publication date: 2002-02-26

Abstract

The invention relates to a fuel cell unit for producing a continuous current by converting chemical energy, using an electrolyte which supports an anode and a cathode separately from each other. Said fuel cell unit has a self-supporting hollow microfibre-matrix electrolyte (2). Said hollow microfibres have a wall thickness of approximately 0.01 to 50&mgr;m and an equivalent diameter of approximately 0.05 to 280&mgr;m. The hollow microfibres are arranged in the form of bonded filament or filament yarn fabrics, in which case the ends (3) of the hollow microfibre are bonded in such a way that they are dimensionally stable and are left at least partially free to allow access to the lumen of the hollow fibre, or bonded staple fibre or staple fibre yarn fabrics, in which case the hollow microfibre ends (3) are bound in such a way that they are dimensionally stable. The invention also relates to a fuel cell stack (1) made up of several fuel cell units of this type, and to the use of a fuel cell unit of this type.

Description

FUEL CELL UNIT The present invention relates to a fuel cell unit for generating direct current by transforming chemical energy with an electrolyte, which carries an anode and cathode separately from each other. The invention further relates to a fuel cell stack which is composed of several of said fuel cell units as well as the use of said fuel cell unit. Fuel cells, as they are generally known, are used for the generation of current, or more exactly the transformation of chemical energy into electrical energy. With this, on the anode, While hydrogen ions are released, electrons are released which charge the anode negatively. Accordingly, two reactions take place on the surface layers of the solid electrolyte, one on the anode and one on the cathode, which together form the beginning of the fuel cell reaction. From the anode (positive pole) the current of the electrode is passed through a current consumer to the cathode (negative pole). Simultaneously with the generation of the electron flow from the anode to the cathode, the emission of the reaction product, for example water or water vapor (distilled water or condensed emission) takes place from the fuel cell. To operate a fuel cell a supply of fuel or working material is required, which may consist, for example, of hydrogen or a hydrogen carrier. The fuel must be transported to the catalytic anode, oxygen or carrier of oxygen, ie the oxidizing agent, to the surface of the cathode which is separated from the anode by the electrolyte. With an ideal electrolyte from a fuel cell, a current generation takes place at a voltage of 1.23 volt. An example of a fuel cell in which the anode and the cathode are formed into a plate and are arranged on either side of a The electrolyte also formed as a plate has been described in US-A-5 418 079. Said plaque-shaped electrolytes have the disadvantage that they must have a relatively large thickness to ensure adequate stability for handling. However, because with the increase in thickness of the electrolyte also the diffusion path of the ions becomes longer, which leads to a higher starting temperature of the fuel cell, said plate electrolytes are only suitable to a limited degree for use in fuel cells. Furthermore, said fuel cells have, at a given volume, a small active surface for the electrochemical reaction. The object of the present invention is, therefore, to indicate a fuel cell unit which in the smallest possible space has a large reactive surface, which is easy to manufacture and exhibits high flexibility in relation to its use .

According to the invention this object is achieved by a fuel cell unit according to claim 1, as well as by a fuel cell stack which is composed of several of said fuel cell units. The fuel cell unit according to the invention for generating direct current by transforming chemical energy with an electrolyte, which carries an anode and a cathode separately from each other, accordingly has a matrix electrolyte of micro-hollow fiber, in which the micro-hollow fibers have a wall thickness of about 0.01 to 50 μm and an equivalent outside diameter of about 0.05 to 280 μm, in which the micro-hollow fibers are arranged either in the form of filament or spun-off layers filaments, in which the micro-hollow fiber ends are stably attached and are at least partially exposed for access to the hollow fiber lumen, or are arranged in the form of staggered fiber or stable fiber spun layers, in which the ends of the micro-void fibers are stably attached. By means of the fuel cell unit according to the invention it is possible to obtain, in a small space, a highly active surface, for example of approximately 11,000 cm 2 per cm 3 of fuel cell volume. It is understood that under an equivalent diameter, as is generally known, for geometrical structures with a cross-section only approximately circular, it is the diameter of that fictitious circle, the area of which is equal to the cross-sectional area of the geometric structure. In the present text "filament layers" refers to layers of fibers with which at least some of the fibers have one or more folds, while fibers in layers of staggered fibers extend without folds. The spun layers are characterized in that several fibers or filaments are bent together. Seeing that according to the invention the solid electrolyte has the shape of hollow fibers, ie a capillary or hollow profile, the small wall thicknesses of the electrolyte can be carried out without problems of mechanical stability. Another advantage of the present invention is that the micro-hollow fibers with the mentioned dimensions have textile properties and for this reason they can be easily deformed without breaking. The inner and outer surfaces of the micro-hollow fibers are activated for their function as an anode or cathode. The type of activation depends on the materials chosen for the micro-heel fibers. For example, activation by means of a suitable coating is possible. The wall thicknesses of the micro-hollow fibers are preferably between about 0.05 and 10 μm, in particular between about 0.05 and 5 μm. In this case, the equivalent outer diameter of the micro-hollow fibers is preferably between about 1 and 100 μm, in particular between about 2 and 25 μm. The concrete choice of suitable diameters and wall thicknesses should be made depending on the materials used. The lower values indicated for wall thicknesses and diameters are determined in particular by the possibilities of manufacturing. According to a preferred embodiment of the invention, the layers are arranged in the form of a disk plate, in which the micro-hollow fiber ends are joined in such a way that a stable self-supporting disc plate ring is formed in the outer annular peripheral surface from which the ends of open micro-hollow fibers are exposed. The disk plate can, seen in cross section, constitute a flat plate or can also have the shape of a layered or corrugated card. The micro-hollow fibers forming the layer preferably have an equivalent diameter of about 0.5 to 100 μm as well as a length of preferably about 50 mm to 1000 mm. In this way, in a volume corresponding to approximately 3 to 5 sheets of DIN A4 an electrolyte surface of approximately 1 m2 can be obtained. Seeing that the micro-void fibers are open at both ends, their length corresponds to the length of the lumen or channel, on the inner surface of which either the anode or cathode is applied. A length of approximately 300 mm is particularly preferred. The chosen length of the micro-hollow fibers preferably corresponds to the diameter of the disk plate ring. The length of the micro-hollow fiber can also be equivalent to a multiple of the diameter of the disc plate by rotating around or bending over the micro-hollow fibers. For ring thicknesses values between approximately 1 mm and 35 mm have shown that they are particularly suitable so that the function of the disc plate ring as a shape stabilizer will be fully realized. The height of the disc plate ring is preferably from about 0.5 mm to 15 mm. This height is sufficient to accommodate several layers of micro-fiber fiber on top of each other. Said ring is suitable for a stack of several fuel cell units. Alternatively, the layers may also be arranged in the form of a polygon, in particular a rectangle, in which the hollow fiber ends are joined in such a way that a polygonal, in particular rectangular, stable, self-supporting structure is formed on the outer surface from which the open micro-fiber ends are exposed . The individual micro-hollow fibers can in this case be arranged either parallel to one another or crossing one another, in which the length of the micro-hollow fibers preferably corresponds to approximately the length or width respectively of the structure. Preferably, the micro-hollow fibers are made of polymer, metal, ceramic and / or textile materials. However, also any other suitable materials can be used. The materials can be oxidic as well as non-oxidic. If non-fluorinated polymer materials are used to manufacture the micro-hollow fibers, then activation can take place, for example, by sulfonation Within the framework of the present invention especially those micro-heel fibers that have proven to be suitable are indicated in the international patent application WO 97/26225, the description of which is included in the present in its entirety.

These are micro-hollow fibers of a ceramic material or the corresponding raw products. When in this connection mention is made of a "ceramic material", this must be understood in the broadest sense. It is a collective name for materials composed of inorganic and mainly non-metallic compounds or elements, which in particular or comprise more than 30% by volume of crystallized materials. In this connection reference is made to Rompp Chemie Lexikon, 9th edition, volume 3, 1990, p. 2193 to 2195. Preferably, the ceramic micro-ceramic fibers consist of an oxidic, silicic, nitric and / or carbid ceramic material. Particularly preferred are said hollow ceramic fibers based on aluminum oxide, calcium phosphate (apatite) or associated phosphates, porcelain or cordierite type compositions, mulite, titanium oxide, titanates, zirconium oxide, zirconium silicate, zirconia, spinel, emerald, sapphire, corundum, silicon nitrides or carbides or other chemical elements or their mixtures. As doping agents, substances known in the ceramics industry, such as MgO, CaO, ZrO2, ZrSiO4, Y2O3 and others or their precursors can be added to the main inorganic constituents. To manufacture these micro-hollow fibers, preferably an emulsion, dispersion and / or suspension, which contains the precursor of a material ~ ^ p of ceramic and a binding agent that can be removed by means of heat, are formed in the known manner in raw micro-hollow fibers and the binder is removed by means of heat. Alternatively, the dispersion may be applied to a core of an organic compact fiber, in which case the core and binder subsequently are removed by means of heat. The dispersion may contain changing amounts, for example up to 95% by mass, preferably approximately 40 to 70% by mass dispersion. A dispersion medium can also be separated when the binder is, for example, thermoplastic and can be melted without appreciable decomposition in a low viscosity compound. As the aforementioned ceramic precursors in particular, the following can be used: mineral clays, in particular kaolin, lita, montmorilite, metal hydroxides such as aluminum hydroxide, mixed metal hydroxides / oxides, such as AIOOH, metal oxides / halides mixed, metal oxides such as BeO, MgO, AI2O3, ZrO2 and ThO2, metal nitrates such as AI (NO3) 3, metal alcoholates, in particular aluminum alcoholates such as AI (iPrO) 3, AI (sec-BuO) 3, magnesium-alumo-silicates, feldspars, zeolites, bombs or mixtures of two or more of the materials mentioned above. In relation to the choice of binder that can be removed by means of heat, there is no critical limitation within the framework of the invention. However, it is preferred that the binder be film forming. It can, for example, be urea, polyvinyl alcohol, wax, gelatin, agar, protein, saccharide. Optionally, in addition to the organic auxiliary agents, as binding agents, suspending agents, defoaming agents and preservatives can be used. The mixture of the precursor of the ceramic material and the binder that can be removed by heat occurs in the form of a dispersion, the term of which must be understood in its broadest sense. They can, in particular, be emulsions and suspensions that occur regularly in the form of a paste. For the selection of the medium of dispersion there is a high degree of freedom. It will generally be water. However, it is also possible to use an organic solvent as a liquid, as an alcohol or acetone, optionally also mixed with water. Particularly advantageous are the so-called sol-gel processes, for example based on the aforementioned polyvinyl alcohol. It should be emphasized that the aforementioned raw product of the micro-hollow fibers can also in principle be used within the framework of the present invention. In this case, it is particularly advantageous to subsequently sulfonate the raw product of the micro-void fibers. This results in the desirable proton conductivity being improved. In order to manufacture the aforementioned micro-hollow fibers as well as the corresponding raw products, in particular within the framework of a spinning process, the process is such that the dispersion is put into a feed tank or pressure vessel of a spinning device , the dispersion is conveyed by flowing at a temperature of about 20 to 400 ° C through the spinning device and is pressed through the nozzle ring openings or nozzle profile openings. The partial flows produced in the area of the nozzle openings are halved by cores or by devices for blowing in a gas, and the partial flows are solidified in raw micro-hollow fibers by heating, by radiation or by feeding in a container of reaction and are then optionally burned to densify the micro-heel fibers. Additional details may be noted from the aforementioned international patent application WO 97/26225. It is further possible to use the hair of the skins of these animal types as micro-fiber fibers, the hair of which has an inner lumen. The skin hair, due to its protein constituents, have a high proton conductivity and are, therefore, suitable for the fuel cell unit according to the invention. Depending on the designed application as well as the fuel to be used, the fuel cell unit can be a PEM, DM and SO fuel cell unit. As you know, the abbreviations "PEM", "DM" and "SO" represent "Proton Exchange Membrane", "Direct Membrane" and "Solid Oxide" respectively. For PEM fuel cell units in particular the raw polymer products of the micro-hollow fibers are suitable, while the micro-hollow fibers of the incinerated stage are particularly suitable for the manufacture of fuel cell units SO. As starting material for high temperature fuel cells, zirconium dioxide and in particular zirconium can be recommended, since this metal has a high absorption capacity for water. Additionally, PEEK (polyetheretherketone) and Victrex® materials have been shown to be suitable within the framework of use according to the invention. By means of a suitable choice of material any type of fuel cell can, therefore, be produced. The anode can be applied on the interior lumen surfaces of the micro-hollow fibers as well as on the outer peripheral surfaces of the micro-hollow fibers. However, for reasons of application the additional details of which will be given below, it is preferred that the anode be provided on the outer periphery of the electrolyte and the cathode on the surface of the inner lumen of the micro-indented fibers in question. According to a particularly preferred embodiment, the fuel cell unit is provided with a microwave distribution cage. This serves to distribute the rays of a microwave heating that is frequently used to put the fuel cell at its starting temperature, ie the temperature at which the chemical reaction takes place.

To avoid short circuits between the individual micro-fiber fibers that form the matrix electrolyte, short-circuit protection can be provided in the form of helix fibers with non-activated surface, which are wound around the micro-hex fibers and are fixed to the ends from the same. The fuel cell units according to the invention can be combined to form a stack of fuel cells, whereby the capacity of the individual fuel cell units can be multiplied practically at will. In said stack the individual fuel cell units may be embedded or fused in such a way that a stable, self-supporting structure is formed. This structure can have any shape, for example a disk plate ring as already explained in the aforementioned. The individual fuel cell units of the fuel cell stack according to the invention may be corrugated or grid-shaped. In this way the individual fuel cell units can be easily placed on top of each other. The fuel cell stack according to the invention may comprise at least one fuel cell unit with non-activated electrode surfaces such as heat exchanger and / or air filter. This is a special advantage of the construction of the fuel cell unit according to the invention with a microwell fiber matrix electrolyte. The heat exchanger and / or air filters can, from ^! fact, consist of electrolyte filaments of matrix of the same material and morphology, the only difference being that their surfaces are not activated so that the chemical reaction desired for the generation of current does not take place on them. The fuel cell unit or fuel cell unit stack according to the invention can thus be manufactured particularly easily in a few steps, in which several elements (fuel cell units, heat exchanger, filter of air, etc.) are first manufactured as identical elements and subsequently a division of the functions takes place by means of a specific activation of the individual micro-heel fibers. The matrix electrolytes of the microfuge fibers according to the invention can be manufactured in the respective individual fuel cell units by pairing (eg, stringing or braiding). The micro-fibers with non-activated surface, which serve as a heat exchanger and / or air filter, are preferably applied to the micro-hollow fibers which act as an electrolyte in an electrically isolated form such that they are entangled in a helical form around the micro-hollow fibers. The winding in the form of an insulated helix is preferably connected to the ends of the matrix of the fuel cell units of the micro-hollow fibers which act as electrolyte in a solid and non-releasable manner, in which the anode surfaces are not reduced. In this way the outer surface of the micro-void fibers of the matrix which acts as an electrolyte remains exposed for fuel access. At the same time the insulated helix acts as a textile contact and touch protection for the outer surfaces of the hollow fibers of the electrolyte matrix. From the individual miniature fuel cells, series circuits in layers and batteries can be produced. In order to manufacture the fuel cell stack, the individual micro-heel fibers can be made in a flat article with random orientation or as a layer according to a scheme. It is possible for whole batteries to be used as heat exchangers, in which case the micro-fiber fibers of those batteries have non-activated surfaces. Stacking individual batteries, stable modules can be manufactured in which stacks with activated micro-fiber fibers and stacks with non-activated micro-indented fibers can be alternated. The non-activated batteries can also act as a cooler, fuel recovery or a preheater. When individual cell fuel cells have a disc plate shape, stacking will result in operational cylinders that are easy to operate. For operation as a fuel cell, micro-void fibers with a wall thickness between 0.05 μm and 40 μm and with an outside diameter of about 0.1 μm to about 50 μm have proven to be particularly suitable. In individual cases the diameter of the lumen can also be up to 100 μm. To get those ~~? 7 small diameters and wall thicknesses, preferably the manufacturing process described in the aforementioned is the one used. When the fuel cell unit according to the invention or the fuel cell stack according to the invention is used for the generation of direct current by transforming the chemical energy released during the oxidation of a fuel, the material that The fuel and oxidizing agent flow is preferably guided in a cross current. This means that one of the flowing materials is guided perpendicular to the plane of the filament or stack pile fiber and the other parallel to this plane. This is in contrast to the operation of the known fuel cells, where the electrolytes are either in the form of plates or in the form of flat films and the material flowing from the fuel and the oxidizing agent is guided accordingly. opposite in parallel along the planes of the plate. With the known fuel cells this arrangement leads to the disadvantage that, for example, the concentration of oxygen in the oxidizing agent becomes lower the more the oxidizing agent has moved along the plane of the plate. In contrast to this, when the fuel cell or fuel cell cell unit according to the invention is used the oxidizing agent, due to the cross current operation mode, can be fed at both ends of the respective micro-heel fibers. . This means that along the entire length of the micro-fiber fiber a substantially constant oxygen concentration is present, as a result of which the - *? The capacity of the fuel cell unit can be kept constant. Fuels containing hydrogen have been shown to be particularly suitable for operating the fuel cell stack according to the invention due to its high reactivity. The reaction products are preferably used for the conditioning, heating, cooling and / or wetting of the fuel cell unit or other connected sequences. The connected sequence can be, for example, a connected fuel cell unit or a separate element of the fuel cell. In this way the fuel is used several times and a particularly economical process can be carried out. In the sense of the multiple use of the fuel, the reaction product of the oxidation, for example water, can also be passed for further use in an air conditioning system, for example in a motor vehicle. To initiate the reaction of the fuel cell, a higher temperature is generally required, which is also called the starting temperature of the fuel cell. This starting temperature can also be obtained according to the invention by passing a heating medium through the fuel cell stack in one of the branches of the cross currents. The heating medium can be, for example, the products of the electrochemical reaction.

The starting temperature of the electrolyte can be obtained by heating the fuel and / or the oxidizing agent before feeding it into the fuel cell unit. The heat required to heat the fuel and / or the oxidizing agent can be obtained, for example, by wetting zeolite. As is known, when they absorb water the zeolites are heated to a temperature of + 70 ° C to + 370 ° C. The wetting of zeolite can in turn take place preferably with the products of the electrochemical reaction (distilled water). The starting temperature of the electrolyte can also be obtained by wetting a metal hydride in particular iron hydride, titanium, magnesium. Also for this wetting it is possible, of course, to use the final product of the electrochemical reaction. Additionally it is possible to obtain the starting temperature by direct or indirect circulation of metal or barium hydroxide smelters. In this connection, barium hydroxide is particularly suitable, since it is liquid at approximately 78 ° C and according to that it can be circulated as a liquid in the desired temperature scale. The metal smelting or barium hydroxide smelting must of course be carried out separately from the material flowing from the fuel and oxidizing agent. The starting temperature of the electrolyte can also be obtained by radiation from the microwave fuel cell unit. In this case the fuel cell or the fuel cell stack and the housing must be manufactured so that the microwaves pass through them, in which case the total unit must be integrated in a microwave distribution cage which the purpose of saving weight is preferably manufactured as a lightweight construction. This form of heating can also be used in combination with one of the other heating methods mentioned above. All the heating methods mentioned have the advantage that they can be carried out without pressure, which is advantageous from the construction point of view. A quick start of the fuel cell can also be carried out by means of an atmospheric catalyst incinerator, that is to say a gas-liquid incinerator. It is also possible to use the catalyst incinerator in combination with one or more of the aforementioned methods to bring the fuel cell or the fuel cells stacked to the temperature. Depending on the type of activation of the catalyst surface, this can take place both before the assembly or assembly of the fuel cell stack and after the commissioning of the fuel cell, for example for a contact one. The outer and inner surfaces of the micro-fiber fiber lumens can also act alternatively as a cathode or anode. The fuel spraying preferably takes place through nozzles, the openings of which are formed as lumens of micro-vortex fibers having a diameter of 0.1 μm to 100 μm and are provided loose in the cast or injection molded parts of the nozzle. In this way a particularly accurate dosage of ^ 'Fuel as well as an extremely fine distribution of it is possible. The fuel injection nozzle, the openings of which are formed as micro-fiber fiber lumens having a diameter of 0. 1 μm to 100 μm and are provided loose in the cast or molded parts by injection of the nozzle, constitute a considerable improvement of the previously known fuel injection nozzles. It is possible to manufacture this nozzle by the aforementioned method with a fluctuation scale of the outer diameter of only about ± 6%. The nozzles with openings of the mentioned sizes and the indicated precision can not, however, be manufactured as usual, making holes in a metal preform by means of laser radiation in view of the fact that this method encompasses a high degree of inaccuracy. To manufacture the ? Nozzle openings according to the invention it is better to place the loose micro-hollow fibers in the injection molding parts or the cast molding parts of the nozzle before they are filled with the material of current nozzle, for example metal. The openings acting as nozzles can, for example, be produced in them after the removal of the micro-hollow fibers with the help of microcable, for example, wire Tungsten shine lamp. In this case, the wire is pulled out of the extrusion pressure profile and thus forms the spray lumen. In the following the invention will be explained in greater detail with reference to the attached drawings which are not given as a limiting example. In the drawings: Figure 1 shows a first embodiment of a fuel cell stack according to the invention. Figure 1a is a cross section of Figure 1. Figure 2 is a perspective view of a second embodiment of a fuel cell stack according to the invention. Figure 3 is a diagrammatic view of the fuel cell stack of Figure 2, in which the circuit of the fuel cell stack according to the invention is shown in particular; Figure 3a is a cross-sectional view of Figure 3 in elevation. In FIG. 1, a fuel cell cell according to the invention is illustrated, which has been given the total reference number 1. The fuel cell cell 1 is composed of micro-vortex fibers 2 which form the electrolyte and as a filament or layer of staggered fiber is formed in a flat article with random orientation or according to a fixed scheme. The solid electrolyte is present, therefore, in the form of a matrix. -i The ends 3 of the individual micro-heel fibers are open and are exposed on the outer periphery of a structure 4, which in this case is a rectangular structure. The structure 4 serves to stabilize the shape and is preferably made of an electrically insulating casting compound. In this case the ends 3 of the micro-hollow fibers 2 can be melted in the structure during the manufacture of the fuel cell stack. However, any other type of incrustation of the micro-hollow fibers 2 in the structure 4 is also possible, for example also simply a loose inlay. The fuel cell stacks according to the invention of the embodiment illustrated in FIG. 1 can be stacked so that a compact, stable, fuel cell square is produced. Around the individual batteries or battery cells a housing 5 is provided which, depending on the mechanical, thermal or chemical stresses or processes on the individual components, can, for example, be made of plastic, metal, glass or ceramic. When microwave radiation is used to heat the fuel cell, a housing material must be used that allows this type of radiation to pass through it, in this case, to protect the operator or user, a distribution cage must be provided around the entire device including the microwave heater. Preferably the housing is made of a dielectric material, so that electrical insulation of the fuel cell cells is ensured.

The fuel cell stack according to the invention can be operated in the form of pressure as well as in the vacuum form. In the first case the housing 5 must be constructed in a manner suitable for the pressure in question. In the present, for example, cylindrical pressure housings have shown that they are particularly advantageous. Figure 1a shows the embodiment of figure 1 in cross section. In the illustrated embodiment the micro-hollow fibers 2 are arranged parallel in one direction (in FIGS. 1 and 1a for reasons of clarity only a few micro-hollow fibers 2 are shown). As already mentioned above, they can, however, be arranged crosswise to one another. The bottom 6 of the housing 5 can be constructed, for example, as a plate bottom so as to be able to withstand higher pressure conditions. For the pressing operation, a compressor 7 is also required, as symbolically illustrated in Figure 1a. In Figure 2 another embodiment of a fuel cell stack 1 according to the invention is illustrated, with which the structure 4 has the shape of a disk plate ring. The micro-hollow fibers 2, of which in FIG. 2 for reasons of clarity are only partially shown, extend along the diameter of the disk plate, in which the hollow fiber ends 3 are exposed at the lateral periphery From the ring. As an example for the sizing of said stack the following values can be indicated: - Diameter of disc plate ring 230 mm - Height h of disk plate ring 5 mm - Thicknesses d of disk plate ring: 35 mm - Diameter outside of the micro-hollow fibers: 10 μm * The active surface of the micro-hollow fibers can be manufactured, in particular, from molecular sieve, activated carbon, graphite, aluminosilicate, zeolite or spongy materials as well as elements and compounds of subgroup 8vo. Figure 3 shows a perspective view of a fuel cell stack 1 with a structure 4 in the form of a disc plate ring 10 as illustrated in figure 2. From this illustration it can be seen how the two electrodes 8, 9 of the fuel cell stack can be arranged on the dielectric structure 4. According to the polished assembly of the electrodes, by placing several fuel cell cells one gasket to the other, a series of circuit can be produced , and stacking them one on top of another another parallel circuit. Figure 3a shows the fuel cell stack of Figure 3 in cross section, in which for larger clarity of the illustration only a micro-hollow fiber 2 extending to the structure 4 is shown. On the outer surface of the fiber micro-socket 2 is located one of the two electrodes 10 of the micro-heel fiber, which may be an anode or cathode. The electrode 10 of the micro-fiber fiber is in direct contact with the corresponding electrode 9 which is provided on the periphery of the structure. From the other of the two micro-fiber fiber electrodes (not shown), which is provided on the inner surface of the micro-fiber fiber, a line leads from the disk plate ring to the second electrode 8 of the disk plate ring . When the anodes are arranged on the inner surfaces of the micro-hollow fibers, the product of the electrochemical reaction will occur on the outer surfaces of the fibers which form the cathode. In this case the contact of the cathode with the housing is obtained directly, and the oxidizing agent or air is filtered through the micro-hollow fiber layers. The fuel cell stack according to the invention can be used among others as an atmospheric fuel cell with closed fuel supply and open elimination of the reaction product, for example water. Additionally, both the vacuum and pressure mode of the operation can be used, the last of which is particularly suitable for use in a motor vehicle, where the wind caused by the trip ensures the vacuum in the fuel cell stack . Individual micro-heel fibers are self-supporting and due to their extremely flexible and resistant textile properties. Due to the thin wall thickness of the micro-hex fibers low starting temperatures can be carried out. The micro-hollow fibers according to the invention can be produced with an accuracy of ± 6% with respect to the fluctuation of the outer diameter and the wall thickness, so that a constant mode of operation is ensured.

The injection nozzle described within the working structure of the fuel cell stack use according to the invention is also suitable for use in other fields, in particular in relation to Otto carburetor engines or diesel engines, in processes of Carnot cycle or other similar procedures or machines. -i

Claims

NOVELTY OF THE INVENTION
CLAIMS € • 5 1.- A fuel cell unit for the generation of direct current through the transformation of chemical energy with an electrolyte, which carries an anode and a cathode separately from each other, also characterized because a) the electrolyte is a micro-fiber fiber matrix electrolyte, b) the micro-hex fibers (2) of the electrolyte have a
10 wall thickness of about 0.01 to 50 μm and an equivalent outside diameter of about 0.05 to 280 μm, c) the micro-hollow fibers are arranged either in the form of filament or spun-off layers of filament, in which the micro-hollow fiber ends ( 3) are united in a stable manner and are at least partially exposed for access to
15 hollow fiber lumen, or are arranged in the form of staggered fiber or layers of stable spun fiber, in which the ends of micro-hollow fibers (3) are stably connected, the layers being arranged in the form of a plate of disk, in which the micro-fiber fiber ends are joined in such a way that a plate ring
The stable, self-supporting disc is formed on the outer annular peripheral surface of which the open ends of the micro-hollow fiber are exposed; or the layers are arranged in the form of a polygon, in particular a rectangle, in which the hollow fiber ends are joined in such a way that a polygonal, in particular rectangular, stable, self-supporting structure is formed on the surface outer periphery from which the open ends of micro-fiber fiber are exposed. . { • 2.- The fuel cell unit in accordance with the
5 claim 1, further characterized in that the wall thickness of the micro-hollow fibers is between about 0.05 and 10 μm, in particular between about 0.05 and 5 μm. 3. The fuel cell unit according to claim 1 or 2, further characterized in that the equivalent outer diameter 10 of the micro-fiber fibers is between approximately 1 and 100 μm, in particular between approximately 2 and 25 μm. 4. The fuel cell unit according to at least one of the preceding claims, further characterized in that the micro-hollow fibers (2) are made of polymer, metal, ceramic and / or textile materials. 5.- The fuel cell unit in accordance with? minus one of the preceding claims, further characterized in that the fuel cell unit is a fuel cell unit PEM, DM or SO. 6. The fuel cell unit according to at least one of the preceding claims, further characterized in that the anode is provided on the interior lumen surface of the micro-hollow fibers (2).
7. - The fuel cell unit according to at least one of the preceding claims 1 to 5, further characterized in that the anode is provided on the outer peripheral surface of the micro-hollow fibers (2).
8. The fuel cell unit according to at least one of the preceding claims, further characterized in that it is provided with a microwave distribution cage.
9. The fuel cell unit according to at least one of the preceding claims, further characterized in that a short circuit protection is provided in the form of helically shaped fibers with non-activated surfaces, which is wound around the micro-hollow fibers and is fixed to the ends thereof.
10. The fuel cell cell (1) containing several fuel cell units according to at least one of the preceding claims.
11. The fuel cell stack according to claim 10, further characterized in that the individual fuel cell units are corrugated or grid-shaped.
12. The fuel cell stack according to claim 10 or 11, further characterized in that it comprises at least one fuel cell unit with non-activated electrode surfaces such as heat exchanger and / or air filter.
13. - The use of at least one fuel cell unit or fuel cell cell according to any of the preceding claims 1 to 12 for the generation of direct current by transforming the chemical energy released during the oxidation of a fuel, further characterized in that the material flows of the fuel and the oxidizing agent are guided in cross current.
14. The use according to claim 13, further characterized in that fuel containing hydrogen is used.
15. The use according to claim 13 or 14, further characterized in that the electrochemical oxidation products are used for the conditioning, heating, cooling and / or wetting of the fuel cell unit or other connected sequences, in particular sequences of connected fuel cell unit.
16. The use according to at least one of claims 13 to 15, further characterized in that the starting temperature of the electrolyte is obtained by passing a heating medium through at least one fuel cell unit or the fuel cell. fuel cell in one of the branches of the cross currents.
17. The use according to at least one of claims 13 to 15, further characterized in that the temperature of

Starting the electrolyte is obtained by heating the fuel and / or the oxidizing agent before feeding them into the fuel cell unit.
18. The use according to claim 16 or 17, further characterized in that the heat required to heat the fuel, the oxidizing agent or the heating means is obtained by wetting zeolite.
19. The use according to claim 16, further characterized in that the starting temperature of the electrolyte is obtained by moistening a metal hydride, in particular iron, titanium, or magnesium hydride.
20. The use according to claim 18 or 19, further characterized in that the final product of the electrochemical reaction is used for wetting.
21. The use according to claim 16, further characterized in that the starting temperature of the electrolyte is obtained by a direct or indirect circulation of metal or barium hydroxide smelters.
22. The use according to at least one of claims 13 to 21, further characterized in that the starting temperature of the electrolyte is obtained by radiating the fuel cell unit with microwaves.
23. - The use according to at least one of claims 13 to 22, further characterized in that the electrolyte starting temperature is obtained with an atmospheric catalyst incinerator.
24. The use according to at least one of claims 13 to 23, further characterized in that the spraying of fuel takes place through nozzles, the openings of which are formed as micro-fiber fiber lumens having a diameter of 0.1 μm to 100 μm and are provided loose in the cast or injection molded parts of the nozzle.
25. A fuel injection nozzle, in particular within the working frame of use according to claim 24, further characterized in that the openings of the nozzle are formed as micro-fiber fiber lumens having a diameter of 0.1 μm to 100 μm and are provided loose in the cast or molded parts by injection of the nozzle.

The present invention relates to a cell unit of

^ ß fuel for the generation of direct current through the

5 transformation of chemical energy with an electrolyte, which carries an anode and cathode separately from each other; the fuel cell unit comprises an electrolyte of self-supporting micro-fiber fiber matrix, in which the micro-fiber fibers have a wall thickness of about

0. 01 to 50 μm and an equivalent outside diameter of approximately 0.05 a

10 280 μm; the micro-hollow fibers are arranged either in the form of a filament or spun-off layers of filament, in which the ends of the micro-hollow fibers are stably attached and are at least partially exposed for access to the hollow fiber lumen, or are arranged in the form of staggered fiber or spun layers of stable fiber, in

15 wherein the ends of the micro-hollow fibers are stably connected; the invention additionally relates to a cell stack of? fuel composed of several of said fuel cell units as well as the use of said fuel cell unit.

SR rcp * jtc * aom * osu * mvh * cgm * P00 / 854F