Fuel cell

An example fuel cell assembly may include a proton exchange membrane (or membrane electrode assembly) that has a first major surface and a second major surface. An anode electrode, which may include a patterned metal layer with a plurality of apertures extending through the patterned metal layer, may also be provided. An anode gas diffusion layer secured to an anode adhesive frame may be situated between the anode electrode and the first major surface of the proton exchange membrane. A cathode electrode may, in some instances, include a patterned metal layer with a plurality of apertures extending through the patterned metal layer. A cathode gas diffusion layer secured to a cathode adhesive frame may be situated between the cathode electrode and the second major surface of the proton exchange membrane. In some instances a fuel cell assembly may be flexible so that the fuel cell assembly can be rolled into a rolled configuration that defines an inner cavity with open ends. A fuel pellet may be inserted into the inner cavity, and one or more end caps may be provided to cover and seal the open ends.

TECHNICAL FIELD

The present disclosure relates generally to fuel cells, and more particularly, to fuel cells and/or components thereof, as well as methods of making fuel cells.

BACKGROUND

A wide variety of fuel cells have been developed. Of the known fuel cells, each has certain advantages and disadvantages. There is an ongoing need to provide alternative fuel cells.

SUMMARY

The disclosure relates generally to fuel cells, and more particularly, to fuel cells and/or components thereof, as well as methods of making fuel cells. An example fuel cell assembly may include a proton exchange membrane (or membrane electrode assembly) that has a first major surface and a second major surface. An anode electrode, which may include a patterned metal layer with a plurality of apertures extending through the patterned metal layer, may also be provided. An anode gas diffusion layer secured to an anode adhesive frame may be situated between the anode electrode and the first major surface of the proton exchange membrane. A cathode electrode may, in some instances, include a patterned metal layer with a plurality of apertures extending through the patterned metal layer. A cathode gas diffusion layer secured to a cathode adhesive frame may be situated between the cathode electrode and the second major surface of the proton exchange membrane. In some instances, the anode gas diffusion layer and the anode adhesive frame lie substantially in a common plane, but this is not required. Likewise, the cathode gas diffusion layer and the cathode adhesive frame may lie substantially in a common plane, but again this is not required.

In some instances, the resulting fuel cell assembly may be flexible so that the fuel cell assembly can be rolled into a rolled configuration that defines an inner cavity with open ends. In some cases, the rolled configuration may be a substantially cylindrical configuration. A fuel pellet may be inserted into the inner cavity, and one or more end caps may be provided to cover and seal the open ends.

The above summary is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The Figures and Description which follow more particularly exemplify various illustrative embodiments.

DESCRIPTION

Fuel cells may be desirable, for example, because they may represent a commercially viable power source that offers a relatively high energy density and a relatively high power density. The use of fuel cell stacks, which may include assembling or stacking a number of layers to form a fuel cell stack assembly, may be important for the manufacturing of such viable fuel cells. For example, some fuel cell stack assemblies may be relatively inexpensive, thin, and flexible. As such, these fuel cell stack assemblies may be capable of being used in a wide variety of fuel cells, in a wide variety of different shapes (e.g., non-planar form factors) and applications. A fuel cell stack assembly may, for example, be rolled or otherwise formed into a desired shape and configured for a variety of uses.

Manufacturing a fuel cell may include a number of processes and/or processing steps. For example,FIGS. 1-4show a number of illustrative steps for forming a fuel cell electrode.FIGS. 5-9show an illustrative method of making a relatively planar fuel cell stack assembly.FIG. 10shows an illustrative fuel cell assembly that has been rolled into a rolled configuration to form an inner cavity that may include a fuel pellet.

As shown inFIGS. 1-4, fabrication of an illustrative fuel cell electrode may, in some cases, begin with a substrate10as illustrated inFIG. 1. Substrate10may include a metal substrate. For example, substrate10may include nickel plated steel, stainless steel, a corrosion resistant metal, or any other suitable material, as desired. The form of substrate10may vary. For example, substrate10may include a generally planar sheet of material. In one example embodiment, substrate10may be about 0.001 to about 0.010 inches thick or so. Other sizes, shapes and/or thicknesses are contemplated.

In the illustrative method, a layer of material12may be disposed on substrate10, as illustrated inFIG. 2. In at least some embodiments, material12may be an insulting and/or dielectric material. For example, material12may be polyimide or any other suitable dielectric material. In one example embodiment, material12may be about 1-10 μm thick or so. Other thicknesses are contemplated.

Next, and as shown inFIG. 3, a layer of metal14may be disposed on material12. Metal14may take the form of a gold layer that is, for example, patterned on the surface of material12with a shadow mask. It is contemplated that other materials and/or methods may be used to dispose metal14on material12.

Next, and as shown inFIG. 4, one or more of layers10/12/14may be perforated to create a plurality of apertures. The apertures may extend through layers10,12, and/or14. Creating the apertures may include, for example, perforating layers10,12, and/or14with an appropriate cutting tool or die, using a cutting laser, using chemical etching, or using any other suitable method, as desired.

Perforations may form a perforated surface16that may include perforation of metal layer14(indicated inFIG. 4with reference number14′), perforation of material12(indicated inFIG. 4with reference number12′), perforation of substrate10(indicated inFIG. 4with reference number10′), or perforation of any combination of these structures. After perforation, the resultant structure may take the form of an electrode18. Electrode18may also be trimmed or otherwise cut or altered, if desired, so as to have the desired shape or configuration. Such an electrode18may be used, for example, as a cathode or anode electrode for a fuel cell assembly, as desired.

The process of forming a fuel cell stack assembly may include “stacking” various layers including electrodes as well as appropriate layers and/or materials between the electrodes.FIGS. 5-9show an illustrative method of making an illustrative relatively planar fuel cell stack assembly.

As shown inFIG. 5, an electrode18may be provided. In this example, electrode18may comprise an anode. However, in other examples electrode18may be a cathode. One or more layers may be disposed on or adjacent to electrode18. For example, inFIG. 6, a gas diffusion layer22aand a layer of adhesive or adhesive frame20amay be disposed on or adjacent to electrode18. In at least some embodiments, layers20a/22amay lie substantially in the same plane as shown. Layer22amay be, for example, an anode gas diffusion layer. The material for gas diffusion layer22amay depend on the application, and in some cases, may include a conductive material, a porous electrically conductive material, a carbon fabric, or the like. Other materials are also contemplated.

In the example illustrated inFIG. 6, adhesive frame20ais generally disposed about the periphery and/or perimeter of gas diffusion layer22a. This allows adhesive20ato join with adhesive20c(discussed below) and effect a gas seal therebetween as discussed below. This arrangement, however, is not intended to be limiting as other patterns, configuration, and/or arrangements are contemplated. Such arrangements may include any suitable method such as, for example, coating, screening, screen printing, combinations thereof, and the like, or any other suitable process.

In some cases, a first major surface of a proton exchange membrane (PEM) (or membrane electrode assembly (MEA))24may be disposed on or adjacent to layers20a/22a, as shown inFIG. 7. The adhesive or adhesive frame20adiscussed above may help secure the electrode18, the gas diffusion layer22aand the membrane24together, and may further help form a gas seal therebetween. PEM24may include any suitable material such as, for example, a carbon and/or platinum coated ion-conductive material.

Another set of layers may be disposed on or adjacent a second major surface of the membrane24. For example,FIG. 7illustrates another gas diffusion layer22cand a layer of adhesive or adhesive frame20cdisposed on or adjacent to the second major surface of the membrane24. In at least some embodiments, layers20c/22cmay lie in the same plane. In some instances, layer22cmay be a cathode gas diffusion layer and/or may include a carbon fabric or other suitable material. Layers20c/22cmay be similar in form and function to layers20a/22adescribed above.

Another electrode26may be disposed on layers20c/22cas shown inFIG. 8. In this example, electrode26may comprise a cathode. However, in other examples electrode26may be an anode. Like above, the adhesive or adhesive frame20cmay help secure the electrode26, the gas diffusion layer22cand the membrane24together, and may further help form a gas seal therebetween. In some instances, the various layers may be compressed such that the layers adhere together and form a single monolithic fuel cell assembly28. InFIG. 9, the joining together of adhesive layers20a/20cis shown to represent the bonding together of the various layers and the forming of a gas seal along the periphery of the single monolithic fuel cell assembly28.

FIG. 10shows a fuel cell assembly30, illustrated in exploded view. Here it can be seen that a fuel cell assembly28may be rolled together into a rolled configuration that defines an inner cavity. In the illustrative embodiment, the edges, for example a first edge32aand a second edge32bof the fuel cell assembly28may be joined together via welding, adhesive, or in any other suitable manner. The rolled configuration may form an inner cavity in which a fuel source or pellet36may be disposed within. Fuel cell assembly30may also include one or more caps such as a first end cap38and a second end cap40to cover the open ends of the cavity.

In at least some embodiments, fuel source36may include a hydrogen source. For example, fuel source36may include a metal hydride. Such materials may be desirable, for example, because it may be possible to recharge these materials with hydrogen. Example metal hydrides may include LaNi5H5, FeTiH2, Mg2NiH4, and TiV2H4. Example chemical hydrides include but are not limited to NaAlH4, LiAlH4, Mg(AlH4)2, Ti(AlH4)4, Fe(BH4)4, NaBH4, and Ca(BH4)2. Other materials are also contemplated.

The resultant fuel cell assembly30may form a power source that may used to power a variety of electronic devices. In some instances, fuel cell assembly30may have a form factor that allows it to be manufactured as a suitable replacement for typical AA, AAA, C, D, 9-volt, or other batteries currently used. In addition, because fuel cell assembly30may utilize a metal hydride for fuel source36, it may be rechargeable such that it can be recharged a relatively large number of times so that the total cost of the fuel cell assembly may be relatively low to the end user.

It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the invention. The invention's scope is, of course, defined in the language in which the appended claims are expressed