Abstract:
A fuel cell apparatus includes tandem storage tanks containing activation devices that release the oxidant gas and fuel gas to the fuel cell membrane when needed. The membrane assemblies surround the storage tanks, overlapping one another in a configuration more suited to use in environments with limited space than the traditional, stacked membrane assemblies. The activation devices are triggered by inertia to puncture membrane valves so that the oxidant gas and fuel gas is kept from the fuel cell membrane prior to inertial triggering and is supplied to the membrane after inertial triggering. The activation devices include spring loaded pivoting arms on supports that swing downward and outward upon subjecting the device to inertial forces.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/634,265, filed Dec. 9, 2004, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a fuel cell, and more particularly to a fuel cell using a polymer electrolyte membrane or the like. 
     2. Description of the Related Art 
     A fuel cell is an electrochemical energy conversion device. Fuel cells use an electrolyte membrane to catalytically react an input fuel, such as hydrogen, with an oxidant, such as oxygen, to produce an electrical current. The electrolyte membrane is sandwiched between two electrodes (an anode and a cathode). A catalyst on the anode promotes the oxidation of hydrogen molecules into hydrogen ions (H + ) and electrons. The hydrogen ions migrate through the electrolyte membrane to the cathode, where a cathode catalyst causes the combination of the hydrogen ions, electrons and oxygen, producing water. The electrons go through an external circuit that serves as an electric load while the ions move through the electrolyte toward the oppositely charged electrode. At the second electrode, the ions combine to create by-products of the energy conversion process, the byproducts being primarily water and heat. The flow of electrons through an external circuit produces electric current. 
     There are several types of fuel cells employing different types of electrolyte membranes, including: a phosphoric acid fuel cell, a molten carbonate fuel cell, a solid oxide fuel cell, and a polymer electrolyte membrane fuel cell, also referred to as a proton exchange membrane fuel cell. 
     The type of fuel cell that involves a polymer electrolyte membrane is hereinafter referred to as a PEM fuel cell. Developments in PEM fuel cell technology have produced fuel cells suitable for applications where the fuel cell will remain dormant for long periods of time before producing energy through electrochemical reaction. PEM fuel cells may include two very small storage tanks to hold the fuel and oxidant gases, such as hydrogen and oxygen, while the fuel cell is dormant. This type of storage tank is sometimes referred to as nanotechnology storage because of its small size. The reaction is initiated after the period of dormancy by the act of fracturing, puncturing, rupturing, or otherwise releasing the gases from the storage tanks to the PEM for the electrochemical reaction. 
     Work on PEM type fuel cells has produced fuel cells in the size range of 0.2 millimeters in thickness and capable of running for over 60,000 hours at 80 degrees Celsius. These PEM fuel cells are capable of producing better than 400 mA (milliamperes) of current per square centimeter, at 0.7 volts, in some applications, depending on whether air or oxygen is used on the cathode. The fuel cells may be stacked to deliver higher voltages. However, despite the advancements made in miniaturization of fuel cells, a fuel cell stacking arrangement is not feasible for some applications due to dimensional limitations of some environments where the fuel cells may be used. 
     For applications where fuel cells of the type described are to replace lithium reserve battery units, known to have a more limited shelf life, the cells may have to be accommodated within a physical location that affords a limited height to width ratio. In such applications, dimensions may be limited to a range of as little as ½ inch high and 1½ inch diameter. As stacked fuel cell assemblies usually exceed such dimensional limits, alternative fuel cell designs are necessary. 
     Required fuel cell performance under certain operational conditions is determined both theoretically and experimentally. When determining required performance of a fuel cell, different operating characteristics must be evaluated because the fuel cell will operate under a variety of abnormal conditions. For example, the fuel cell will provide energy below the normal Polymer Electrolyte Membrane fuel cell operation temperature of around 80 degrees Celsius. Fuel cells are also capable of running on pure oxygen or air, at pressures higher than atmospheric, and without hydration. 
     According to DuPont, Inc., the manufacturer of Nafion®, one of several possible membrane materials that may be used in the fuel cell, operating characteristics such as higher pressure and pure oxygen as the oxidant gas will improve performance of the fuel cell from the performance under normal conditions. However, though the fuel cell will operate without hydration, lack of hydration reduces fuel cell performance and can offset improved performance that results from other positive changes in operating conditions. 
     Available literature indicates that this increase in performance under certain conditions is due to a higher Gibbs free energy value. When one or more of the potential driving forces behind a chemical reaction is favorable and other factors are not, the Gibbs free energy value (G) reflects the balance between these forces. Gibbs free energy is measured by the relationship between system enthalpy and system entropy. The change in Gibbs free energy that occurs during a reaction is equal to the product of the change in temperature and the change in entropy of the system subtracted from the change in enthalpy of the system. 
     Performance curves can be generated to predict fuel cell voltage and current values of stacked membrane assemblies and alternative fuel cell configurations. In  FIG. 4 , a collection of performance curves has been generated to show the performance of a fuel cell under various conditions as indicated in the caption under the graph. The four performance curves grouped together on the higher portion of the chart in  FIG. 4  show the expected performance of a hydrated fuel cell at various conditions. The conditions indicated are two different operating temperatures, 22 degrees C. and 80 degrees C. and two different pressures, 14.7 psi and 500 psi. The two performance curves toward the bottom of the chart in  FIG. 4  show the expected performance without hydration, where one is for a fuel cell having the size of a D-size battery and the other curve is for a fuel cell according to the present invention, which is indicated as MOFA for Multi-Option Fuse for Artillery. The curve toward the top of each series demonstrates the performance of the Polymer Electrolyte Membrane (PEMERY™) battery curve, while the curve labeled “D” Size indicates where the performance of a typical D-sized PEMERY™ style battery would fall on the chart. 
     Another limitation presented by the environments in which polymer electrolyte fuel cells may be used is the ways in which the electrochemical reaction may be initiated after the long period of dormancy. The inventor has developed piston-type activators that can be used to initiate reaction in a fuel cell, but such activators are generally not easily adapted for use in all applications. 
     SUMMARY OF THE INVENTION 
     The present invention provides a fuel cell apparatus and method for addressing the need for specific power output requirements in environments where the space for a fuel cell or battery is limited. Rather than stacking polymer electrolyte membrane assemblies as has been done in prior developments, the membrane assemblies are wrapped around the core of the fuel cell, which contains the fuel gas and oxidant gas, in an overlapping fashion. 
     In another aspect of the invention, the fuel cell is configured to store fuel gas and oxidant gas within the confines of the fuel cell, with no need for external sources of fuel for the electrochemical reaction. 
     In yet a further embodiment, the fuel cell is configured to remain balanced while operating in a moving environment. 
     In yet another aspect of the invention, the activation of the electrochemical reaction in the fuel cell may be initiated by the motion of the environment in which the fuel cell is used through an activation device that is held in place until the appropriate force is applied to the fuel cell. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1   a ,  1   b ,  1   c ,  1   d ,  1   e ,  1   f ,  1   g ,  1   h ,  1   i ,  1   j ,  1   k ,  1   l ,  1   m , and  1   n  are side cross sectional views and plan views of the components of the gas storage tank and baffle configuration, with the locations of ports and other openings indicated, according to the principles of the present invention; 
         FIGS. 2   a ,  2   b ,  2   c ,  2   d ,  2   e ,  2   f ,  2   g ,  2   h ,  2   i ,  2   j ,  2   k ,  2   l ,  2   m ,  2   n ,  2   o ,  2   p ,  2   q , and  2   r  are side and end views of the inertial switch subassembly, as well as a side and end views of each component of the subassembly, according to the principles of the present invention; 
         FIGS. 3   a  is a side view of the exterior of the fuel tank assembly and  FIG. 3   b  is a top plan view of the fuel tank assembly of the fuel cell; 
         FIG. 4  is graph of performance curves of embodiments of a PEM fuel cell operating with and without hydration at various operating parameters; 
         FIG. 5  is a schematic illustration of a series connection of fuel cell membrane elements to form a fuel membrane assembly; 
         FIGS. 6   a  and  6   b  are an end cross-sectional view of the fuel cell assembly with the membrane assemblies from  FIG. 5  in place and an enlarged view of a portion of the fuel cell membrane; 
         FIG. 7  is a enlarged view of a portion of a fuel cell assembly; and 
         FIGS. 8   a  and  8   b  is both a side view and cross sectional view of a preferred embodiment of the fuel cell. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1   a  through  1   n , a fuel cell according to an embodiment of the present invention includes a gas storage tank  10  shown in side cross sectional view in  FIG. 1   a  and in end view in  FIG. 1   b . The tank  10  has a substantially circular cross section with a circular sidewall  11  and is subdivided into subunits or compartments  12  and  14  for separate storage of hydrogen and oxygen gas, as is apparent in  FIG. 1   b . The subunits are defined by baffles  16  which are placed in a substantially x-shaped configuration, defining four separate subunits or compartments in the storage tank  10 . The baffles  16  are positioned along the full length (or height) of the storage tank  10  and are affixed to inside of the wall  11  the storage tank  10 . In one embodiment, the tank  10 , as shown in  FIG. 1   a  has a diameter of 1.12 inches. 
     In  FIG. 1   b , the baffles  16  may be arranged so that the angles defined by the substantially x-shaped configuration are approximately 60 degrees and 120 degrees. Ports  18  and  20  are placed or otherwise formed in the baffles  16  so as to interconnect both 60 degree subunits to one of the 120-degree subunits. The generally expected proportion of hydrogen gas storage to oxygen gas storage in a tandem tank fuel cell is about two-to-one. The relevant proportions or sectors of a full annular profile, as expressed in degrees, would be in the range of 240 degrees for hydrogen storage and 120 degrees for oxygen storage. Other proportions of reactants are possible, and thus other proportions of tank sections may be provided. The tandem arrangement of the gas storage serves to maximize the gas storage and delivery system of the fuel cell, while minimizing the fuel cell&#39;s overall profile. The arrangement additionally serves to keep the hydrogen and oxygen gases isolated without requiring a complicated system to delivery the hydrogen and oxygen gases to a anode  78  and cathode  76  when needed. 
     In  FIG. 1   b , the storage tank  10  is divided into complementary portions by baffles  16 . The portions defined by the baffles are connected by ports  18  and  20  to form appropriate proportions for storing hydrogen and oxygen gases. Alternatively, two separate tank subunits could be constructed in shapes and proportions required for the desired size and end application of the fuel cell. The latter fabrication may provide better gas containment, but the construction could be more complex and expensive 
     The arrangement of the baffles  16  in the storage tank  10  also serves to provide balance for the storage tank  10  and the fuel cell as a whole. The fuel cell may be utilized in applications where the device the fuel cell is powering will be in a spinning motion and a properly balanced fuel cell will not disrupt the intended motion of the application. This invention can be applied in a variety of environments including, but not limited to, ordnance environments, personal safety alarms, emergency or investigatory tracking devices, deep space and undersea exploration, as well as any other appropriate applications. As many of these environments may involve motion of the apparatus containing the invention, a properly balanced fuel cell and gas storage unit are important. 
     The storage tank  10  in  FIG. 1   a  is completed by covering a top  22  and a bottom  24  of the cylindrical wall to form an enclosure. The covering is configured to fit over the ends of the tank  10  and abut the ends of the baffles  16 . In one embodiment, two of the baffle sections have extensions  25  and  27  that extend beyond the top  22  and bottom  24  of the storage tank  10 . The baffle extensions  25  and  27  fit end plates as shown in  FIGS. 1   d - 1   j . The extension portions of the baffles  16  extending beyond the top  22  and bottom  24  as indicated in  FIG. 1   b  correspond to the proportion of gases used in the fuel cell. The plate for covering the top  22  is in the illustrated embodiment formed in two pieces  26  and  28  as shown in  FIGS. 1   c ,  1   d ,  1   e  and  1   f , so as to conform to, and fit over, the top ends of each of the subunits or compartments  12  and  14  defined by the baffle  16  extensions  25  and  27 . The baffle extensions  25  and  27  correspond to baffles  16  that are not provided with ports to link adjacent subunits, whereas the other baffles  16  are provided with the ports  18  and  20  for communication by the stored gases. The plate covering the bottom  24  is formed in two pieces  30  and  32 , as indicated in  FIGS. 1   g ,  1   h ,  1   i  and  1   j  so as to conform to, and fit over, the bottom ends of each of the subunits or compartments  12  and  14  as defined by the baffle  16  extensions  25  and  27 . The top and bottom plates  26 ,  28 ,  30  and  32  close the subunits  12  and  14  and keep the gasses in the compartments separate from one another for those subunits not linked together with the ports  18  and  20  in the baffles  16 . This construction makes it easier to isolate the subunits. The assembly is welded together, for example, by brazing or by a laser welding system. 
     Alternatively, the storage tank  10  or hydrogen and oxygen compartments  14  and  12  may have pockets machined into the walls where the top and bottom plates  22  and  24  may fit. Another possible embodiment might use machined areas in the storage tank  10  walls to properly position the top and bottom plates  22  and  24 , rather than using the machined areas to hold the top and bottom plates  22  and  24  in place. The tank body  10  of one embodiment is wire cut from  304  stainless steel plate or bar stock. The top and bottom pieces  26 ,  28 ,  30  and  32  are machined from  304  stainless steel flat stock. 
     In  FIGS. 1   g ,  1   h ,  1   i  and  1   j , in the bottom plate  24  formed by the two parts  30  and  32  have at least two gas charging ports  34  are machined, or otherwise formed, to enable charging of gases to the storage tank  10 . In the bottom plate  24  at least two additional access ports  36  are machined or otherwise formed. One of the access ports  36  is for the hydrogen subunit  14 ; and a second access port  36  is for the oxygen subunit  12 . Activation devices  50  will be inserted into each subunit through the access ports  36  and welded in place in final assembly. The activation devices  50  may also be placed into pockets machined into either the top plate  22  or bottom plate  24  of the storage tank  10 , the machined pockets eliminating the need for the access ports  36 . Alternatively, the access ports  36  and gas charging ports  34  may be located in the top plate  22  of the storage tank  10 . 
       FIGS. 1   k ,  1   l ,  1   m  and  1   n  show two bushings  38  and  40  that are machined, or otherwise formed, for insertion into the ports  34  located generally 180 degrees apart toward the bottom of the storage tank  10 . These ports may, or may not, have the bushings  38  and  40  pressed in them. The ports  34  with the bushings  38  and  40  connect the storage tank  10  with the anode  78  and cathode  76  to allow hydrogen gas to flow out of the storage tank  10  to the anode  78  and oxygen gas to flow out of the storage tank  10  to the cathode  76 . The ports  34  and bushings  38  and  40  are formed in the storage tank  10  walls, but the inner wall  90  of the storage tank  10  seals off the access to the ports  38  and  40  until the inner wall  90  is pierced by the activation devices  50  at the exact locations of the at least two ports  34 . To achieve a reliable break in the storage tank walls  90  when the inertial arm  60  is activated, the at least two ports  34  are machined or otherwise formed to a precise, close, appropriately thin, dimension as determined by the specifics of the design and application. In the embodiment of the invention where the access ports  36  and gas charging ports  34  are located in the top plate  22  of the storage tank  10 , rather than the bottom plate  24 , the ports  38  and  40  located in the walls of the storage tank  10 , should be placed toward the top of the storage tank  10 , rather than the bottom of the storage tank  10 . 
     The present inertial switch is configured to operate when the device is subjected to sufficient inertial force. Small inertial forces will not overcome the spring bias and so there may be considered to be a threshold of inertial force to trigger operation of the inertial switch, and thus opening of the gas storage containers and initiation power generation by the fuel cell. Selection of materials and construction of the inertial switch components and of the membrane to be pierced by the inertial switch enable the threshold to be changed, as desired. Thus, the present device may be configured to operate in different applications by such selection. 
     The construction of a sealed storage tank  10 , divided into compartments for holding oxygen gas  12  and hydrogen gas  14  separately is designed to allow the fuel cell to be held dormant for an extended period of time. The inner wall  90  of the storage tank  10  must be of a thickness that the activation devices  50  are capable of piercing, but also sturdy enough to ensure that the fuel cell will be stable in the dormant state. 
     The storage tank  10 , including the two subunits  12  and  14  and the top and bottom closures or plates  22  and  24 , can be made from any suitable material and manufacturing process, for example, from machining or forming, from bar stock to powered metal technology, or worked from generally flat stock. Whatever method is selected as the most cost effective for the production volumes encountered, the final welded assembly should be spin balanced either individually, or collectively. The storage tank  10 , baffles  16 , top and bottom plates  22  and  24 , ports  18  and  20 , and segments of top and bottom plates  26 ,  28 ,  30 , and  32  as well as any other component parts, may be coated to prevent gas leakage, oxidation, and hydrogen embrittlement. The protective coating also serves to ensure that the fuel cell will remain stable when left dormant and will be ready for use when desired by maintaining the integrity of the storage tank  10  and activation devices  50  during any period of dormancy. The protective coating selected will depend on the metals used in construction of the storage tank  10  and associated parts. The internal plating or coating of the storage tank  10  may be done after final assembly of the storage tank  10 , but should be done before the activation devices  50  are installed and access ports  36  are welded shut. 
       FIGS. 2   a  through  2   r  show one embodiment of an activation device used to trigger the electrochemical reaction in the fuel cell. In this embodiment, the activation device  50  takes the form of an inertial switch. The activation devices  50  are placed in the access ports  36  in the bottom plate  24  of the storage tank  10 . One activation device  50  is used in the portion of the storage tank  10  dedicated to oxygen storage  12  and one activation device  50  is used in the portion of the storage tank  10  used for hydrogen storage  14 . 
     A variety of activation devices may be employed in the fuel cell, depending upon the environment in which the fuel cell will be used. For example, in an environment where the fuel cell will be “on board” or embedded within a portion of a moving carrier, such as within a projectile “round” in an ordnance application, an activation device which relies upon G-forces or centrifugal forces would be appropriate. The inventor has developed piston-type activators as well, but such activators are generally not easily adapted for use in the present invention. In the embodiment pictured in  FIGS. 2   a - 2   r , the activation device  50  includes a base  51  with a vertical support  53  and an arm support  55  holding an inertial arm  60 . The activation device  50  is a subassembly, two of which are installed within the storage tank  10  of the fuel cell, one for the hydrogen and the other for the oxygen. The base  51  is screwed in or pushed in to position in the opening  36  (see  FIGS. 1   g  and  1   i ) within the tank, depending on whether threads or a push fit connection is desired. In either mounting, the base  51  of the activation device  50  is preferably welded in place in the opening  36  after assembly to close the tank. 
     The base  51  is shown separately in  FIGS. 2   f  and  2   g . The base  51  is formed of by machining 0.050 inch thickness  304  stainless steel and in one embodiment has a diameter of 0.40 inches. The vertical support  53  as shown in  FIGS. 2   c ,  2   d , and  2   e  is formed preferably by stamping 0.010 inch thickness  304  stainless steel. The vertical support has a platform portion  57 , an upright portion  59  and a crossbar  61 . The platform  57  is fastened to the base  51 , in the preferred embodiment, by welding, such as welding at four places. In an optional embodiment, the upright  59  is strengthened by forming a strengthening rib on the upright. This will enable the upright  59  to resist twisting in high spin conditions. The cross arm  61  supports the inertial arm.  60 . The inertial arm  60  is shown individually in  FIGS. 2   q  and  2   r.    
     In  FIGS. 2   a - 2   r , the activation device  50  is composed of a spring washer  52  ( FIGS. 2   i  and  2   j ), a back off spring  54  ( FIGS. 2   k  and  2   l ), a weld stud  56  ( FIGS. 2   m  and  2   n ), a Teflon bushing  58  ( FIGS. 2   o  and  2   p ), and the inertial arm  60  ( FIGS. 2   q  and  2   r ), as well as a base sub assembly  63  formed by the base  51  and vertical support  53  ( FIG. 2   h ). The inertial arm  60  may take a variety of shapes, but should be generally long and narrow in construction with a conical piercing element at one end. The inertial arm  60  may be tapered from a pivot area toward an enlarged impacting end that would maximize the impact of the inertial arm  60  on the storage tank wall  90 . If desired, the impacting end of the inertial arm  60  may take the form of a hammer head for additional impact energy. The inertial arm  60  may be round, square, rectangular, or other polygonal shape or configuration in cross section. A narrow strip of rectangular bar stock, as shown in  FIG. 2   q  and  2   r , will accomplish the desired objective, piercing the storage tank wall  90  to open the port  38  or  40  to the anode  78  or cathode  76 , with little loss of effectiveness. 
     The inertial arm  60  may be approximately 0.050 by 0.050 inch in cross section, and about 0.350 inch long. In one embodiment it is formed from  304  stainless steel. The inertial arm  60  is mounted at one end to the base sub assembly  62 , leaving the other end free to contact the side of the storage tank  10 , puncturing the wall and opening the port  38  or  40  to allow oxygen or hydrogen to flow into the fuel cell assembly. The active end of the inertial arm  60  contains at least one projection  64  with a relatively sharp point. The projection  64  can be made from a hard tool steel, coated with a hard material, or comprise an insert to the inertial arm  60  made of carbide or a similar hard material. On the other end of the inertial arm  60  is a thru hole  68  used to mount the inertial arm  60 . The thru hole  68  may encompass the bushing  58  or a coating to reduce friction. 
     The arm support  63  can, for example, be fabricated from metal as a stamping on a progressive die. On the arm support  63 , a pivot pin  66  may be mounted by resistance welding, or other methods, although retaining clips and other fastening methods may also be used for this purpose. To prevent the projection  64  on the inertial arm  60  from blocking the punch-thru point in the wall  90  after activation, which could inhibit gas flow, a spring clip or back off spring  54  is designed to fit over the inertial arm  60 . It also could be mounted to the arm support  63  or the tank wall  90 . The spring clip or back off spring  54  may also be fabricated from metal as a stamping on a progressive die. 
     The activation device  50  is mounted on the base sub assembly  62 . The base sub assembly  62  of each of the two activation devices  50  is made to match the two access ports  36  in the bottom plate  24  of the storage tank  10 , one for each subunit. The activation devices  50  and base sub assemblies  62  may be positioned in the storage tank  10  so as to maintain the balance of the fuel cell in operation. After welding the activation devices  50  and base sub assemblies  62  into place in the bottom plate  24  of the storage tank  10 , the tank may be spin-balanced again. Alternatively, the activation devices  50  may be mounted directly to the top plate  22  of the storage tank  10 . This could be accomplished by machining supports in the top plate  22  or by welding or otherwise attaching an appropriately designed support bracket to the top plate  22 . 
     The inertial arm  60  is mounted at a pivot point to allow it to swing after the ordnance launch or other activation event. The activation device  50  must also incorporate support for the inertial arm  60  to prevent premature or inadvertent puncture of the storage tank wall  90 . The spring washer  52  shown in  FIG. 2  is intended to maintain the proper positioning of the inertial arm  60 , leaving space between the inertial arm  60  and the storage tank wall  90  until the desired activating action is taken and the forces intended to activate the fuel cell overcome the spring washer  52 . The spring washer  52  is preferably implemented to move back under “G” or spin forces, and to allow the inertial arm  60  to break loose. Math models show that in the case of an ordnance environment, the forces of launch are more than sufficient to achieve the proper break away. Alternative methods for maintaining the proper position of the inertial arm prior to activation include tabs or other breakaway devices that would serve the same purpose. 
     In operation, the spring clip or back off spring  54  engages the storage tank wall  90  as the inertial arm  60  swings downward. The force generated by the environment in which the fuel cell is placed overcomes the force holding the inertial arm  60  in place. The inertial arm  60 , pivoting at the point  68  on which it is mounted, until it strikes and pierces the storage tank wall  90  at the designated points. Subsequent to the piercing motion, the back off spring  54  causes the inertial arm  60  to withdraw from the point at which the storage tank  10  was pierced, opening the port  38  or  40  to gas flow. While a device that pulls the inertial arm  60  back from the openings made in the storage tank wall  90  is one way to prevent the inertial arm from impeding gas flow into the anode and cathode gas diffusers  72  and  74 , the invention is not limited to this one embodiment. Other solutions to the problem, including grooves machined into the projection  64  that pierces the storage tank wall  90 , would also ensure that the oxygen and hydrogen gases could exit the storage compartments  12  and  14  smoothly and would negate the need for the back off spring  54 . 
     Once the activation devices  50  are installed and the storage tank  10  and activation device  50  assembly is balanced, the storage tank  10  can be charged with hydrogen and oxygen using any suitable method. The air may be evacuated from the storage tank  10  prior to charging. The remainder of the fuel cell may be evacuated at this time as well. After charging the storage tank  10  with hydrogen and oxygen into the appropriate compartments  12  and  14  through gas charging ports  34 , the storage tank  10  may be mechanically sealed and then welded shut to form the storage tank  10  assembly pictured in  FIG. 3   a.    
     During the final welding process the gases must remain separated and the storage tank compartments  12  and  14  must remain intact. If needed, all welding may be carried out in an inert gas atmosphere to prevent contamination of the welds. After the final welding is completed, the storage tank  10  as pictured in  FIGS. 3   a  and  3   b  is then ready to be assembled to the fuel cell to complete the PEMERY™ battery. The charging ports  34  and access ports  36  are shown in  FIG. 3   b . The illustrated tank assembly  10  of  FIG. 3   a  has dimensions of 1.120 inches in overall diameter, a height of 0.670 inches, and a diameter at the end caps  26  and  30  of 1.080 inches. 
     The performance curves pictured in  FIG. 4  indicate that the fuel cell described in this application could generate 0.44 volts at 350 mA draw. To achieve the design voltage and amperage, sixteen individual membrane electrode assemblies  70 , with dimensions of 0.640 inch high by 0.740 inch wide and a surface area of about 3.0 cm 2  each, are connected in a series circuit as illustrated schematically in  FIG. 5 . In the present embodiment, the maximum current draw is estimated at 350 ma (just under 120 ma per cm 2 ), which delivers an operating voltage of about 8.3 VDC from the fuel cell. This level of performance exceeds the system requirements, i.e. fuse power needs. 
     The invention is not limited to the illustrated and described embodiment. Alternative combinations of fuel cells include, but are not limited to, a configuration where eight membrane electrode assemblies are placed in the PEMERY™ battery. The embodiment using eight membrane electrode assemblies would provide more surface area, spreading out the current draw and generating a higher voltage to partially offset the smaller number of membrane electrode assemblies used. This embodiment would provide approximately 5.8 volts at 325 mA of current draw. These specifications meet the requirements of most ordnance systems. The number of membrane electrode assemblies is determined by the required operating voltage of the system, rather than by any set design configuration. The versions described here are suggested for use in one particular application. Other applications of the fuel cell may require different numbers of membrane electrode assemblies to generate the required voltage. 
     In  FIG. 5 , the membrane electrode assemblies  70  are shown connected in a series circuit. This arrangement is accomplished in one embodiment by overlapping the ends of each membrane electrode assembly  70  to create one continuous assembly. The resulting series of membrane electrode assemblies  70  may be wrapped around the storage tank  10  assembly as pictured in  FIGS. 6   a  and  6   b.    
       FIG. 6   a  provides additional detail on an embodiment of the invention having serially connected individual membrane electrode assemblies  70 . Each membrane electrode assembly  70 , as shown in  FIG. 6   b , may take the form of an “s” shape, with an anode  78  on one side, a cathode  78  on the other side, and a polymer electrolyte membrane  80  (or other suitable membrane material) in the center. This “s” shape may be as shallow or deep as needed, and may also take the form of multiple “s” shapes to maximize the area of the membrane electrode assemblies for the occupied space. 
     As the number of membrane electrode assemblies  70  needed and surface area required per membrane electrode assembly  70  increases, was determined through the use of the performance curves in  FIG. 4 ,  FIG. 6   a  demonstrates an arrangement of the membrane electrode assemblies  70  placed into the PEMERY™ battery. The space allocated for the membrane electrode assembly  70  is the space between the storage tank outer wall  92  and the inner side of the outer wall  94  of the PEMERY™ battery device. In the present embodiment, the diameter of the storage tank  10  is approximately 1.12 inches and the diameter of the inside of the PEMERY™ battery is approximately 1.44 inches. The difference between the two diameters, 0.320 inches, must be divided in two sections to accommodate the configuration of wrapping the membrane electrode assemblies  70  around the storage tank  10 . The present embodiment allows approximately 0.160 inch for the membrane electrode assemblies  70  between the inner wall of the PEMERY™ battery  94  and outer wall of the storage tank  92 . When the membrane electrode assemblies  70  is placed into the PEMERY™ battery, it takes the form of a cylinder 0.640 inch high with an outer diameter of 1.44 inches and an inner diameter of 1.12 inches. 
     When the a membrane electrode assembly  70  is placed in the corrugated surfaces of the cathode and anode gas diffusers  72  and  74 , the membrane electrode assembly  70  forms an “S” shape as shown in  FIG. 6  in a cross sectional view. As the next membrane electrode assembly  70  is laid into the corrugated shape, it completes an electrical circuit by placing the outside of the first membrane electrode assembly  70  on the inside of the second membrane electrode assembly  70 , as there is a designed-in overlap on the membrane electrode assemblies  70 . These two membrane electrode assemblies  70  are then in series electrically. As additional membrane electrode assemblies  70  are added, they also connect electrically such that when all are in place, there are sixteen membrane electrode assemblies  70  in a series electrical circuit. With the membrane electrode assemblies  70  in place and connected, the anode gas diffuser  74  is placed on the membrane electrode assemblies  70 . The anode gas diffuser  74  can be two or more pieces, since a diffuser made from one piece will be difficult to implement in the present embodiment. Additionally, a gasket, not illustrated in the drawings, may be required at the top and bottom of the PEMERY™ battery to prevent the membrane electrode assemblies  70  from shorting out on the case of the battery  94 . Finally, glues and sealants may be used during assembly to prevent gas leaks during fuel cell operation. 
     Referring again to  FIG. 6   a , the cross section of the PEMERY™ battery indicates not only the respective positions of the membrane electrode assemblies  70  and storage tank  10  within the outer walls of the PEMERY™ battery  94 , but also demonstrates the way in which oxygen and hydrogen are delivered to the membrane electrode assemblies  70 . 
     The cathode is where the oxygen is introduced to the fuel cell membrane. Cathode gas diffuser material  72  is located between the membrane electrode assemblies  70  and the inner wall of the PEMERY™ battery casing  94 . The cathode gas diff-user  72  shown in  FIG. 6   a  is composed of a solid porous material. The solid porous material may be metal, polymer, or any other suitable material. It is also possible that other materials, including non-solid materials may be used for the gas diffuser material  72 . The cathode gas diffuser  72  fits around the storage tank  10  and supports the corrugated membrane. The gas flow port  38  extends into the cathode gas diffuser  72 . The inner surface of the cathode gas diffuser  72  may be sealed with the appropriate sealant to the storage tank  10 . The outer surface of the cathode gas diffuser  72  may have a corrugated shape, similar to a washboard. The cathode gas diffuser  72  may be made in one or more pieces, then assembled to the storage tank  10 . The corrugated surface covers the outer surface of the gas storage tank  10 , providing the surface that molds the membrane electrode assemblies  70  into the “s” shape as previously discussed and pictured in  FIGS. 6   a  and  6   b.    
     Anode gas diffuser material  74  shown in  FIG. 6   a  is located between the membrane electrode assemblies  70  and the outer casing of the PEMERY™ battery  94 . The anode gas diffuser  74  is where the hydrogen gas is introduced to the membrane electrode assembly  70 . The gas port  40  bringing the hydrogen gas to the anode  78  is longer than the gas port  38  directing oxygen to the cathode  76  so that it may extend past the membrane electrode assembly  70  into the anode gas diffuser  74  where is allows the fuel gas, hydrogen in this case, to flow into the anode gas diffuser  74  isolated from the cathode  76 , cathode gas diffuser  72 , and oxygen gas. Electrical connections are made to the exterior of the PEMERY™ battery and the storage tank  10 , membrane electrode assemblies  70 , and gas diffusers  72  and  74  are placed into a formed metal shell  94  with appropriate sealing to complete the PEMERY™ battery.  FIG. 6   a  illustrates some key angular dimensions in accordance with one embodiment of the invention. 
     Turning next to  FIG. 7 , an enlarged cross section of a portion of the fully assembled fuel cell shows the present apparatus in detail. As indicated in the drawing, several applications of the fuel cell involve rotation of the fuel cell assembly, as indicated by arrow  100 . The rotation of the fuel cell assembly may accomplish more than just providing the force needed to activate operation of the fuel cell, it may also provide force needed to push water formed by the electrochemical reaction through the membrane  80 , maintaining proper membrane  80  hydration during operation. This is accomplished by positioning the anode  78  on the outside of the membrane electrode assembly  70  when in place in the fuel cell assembly. The hydrogen gas port  40 , seen activated in  FIG. 7  by having been punctured by the inertial arm of the switch  50 , channels the hydrogen gas past the cathode gas diffuser  72 , cathode side  76  of the membrane electrode assembly  70 , and membrane  80  to the anode gas diffuser  74 . The electrochemical reaction generates water as a byproduct on the cathode side  76  of the membrane electrode assembly  70 , located on towards the inside of the fuel cell. The water is pushed outward by the centrifugal force of the spinning movement of the fuel cell. Thus, the arrangement of the cathode  76  on the inside and the anode  78  on the outside is designed to maintain hydration and effective functioning of the fuel cell during operation. This effect will create a kind of self hydration effect that will increase the performance of the fuel cell, which has, until now, been purposely kept dry to prevent freezing damage during cold storage. 
     Water on the anode side  78  of the membrane electrode assembly  70  aids in the migration of the protons created by the catalyst in breaking down the hydrogen atoms. The cathode  76  is provided on the inside of the spin, and the hydrogen on the outside of the spin. If spin is not an aspect of the environment in which the fuel cell is used, there will be some movement of water through the membrane via osmosis and the vapor pressure of the water.  FIG. 7  shows this effect in an embodiment of the present invention which uses eight membrane electrode assemblies  70  in series instead of sixteen membrane electrode assemblies  70  in series. This embodiment delivers a lower electrical power than the sixteen membrane electrode assembly  70  embodiment previously described, as it involves fewer assemblies  70  and smaller surface area. One advantage of the eight membrane electrode assembly  70  embodiment is an increase in internal volume for gas storage of the hydrogen and oxygen, which yields a longer run time. 
     The removal of water from a fuel cell is another critical factor in fuel cell performance. If experimentation should determine that water removal from the fuel cell is more important than hydration of the fuel cell for performance in a desired application of the invention, an alternative embodiment may be used. In this alternative embodiment, the anode side of the membrane electrode assembly  78  and anode gas diffuser  74  would be placed towards the inside of the fuel cell, adjacent to the storage tank  10 . The cathode side of the membrane electrode assembly  76  and cathode gas diffuser  72  would be placed towards the outside of the fuel cell, adjacent to the casing  94 . In this embodiment, water generated as a byproduct of the electrochemical reaction would be pushed to the outside wall of the battery  94  by centrifugal force. In this embodiment, the longer port  40  would be connected to the oxygen storage compartment  12  and the shorter port  38  would be connected to the hydrogen storage compartment  14 . 
       FIGS. 8   a  and  8   b  illustrate the fuel cell assembly with all parts in place, a complete illustration of one embodiment of the invention.  FIG. 8   a  and  8   b  illustrate, in cross sectional views, a representation of an assembled Polymer Electrolyte Membrane Battery, or PEMERY™ battery Multi-Option Fuse for Artillery (MOFA) in accordance with one embodiment. The two inner subunits or compartments  12  and  14  with the inertial arms  60  are the hydrogen and oxygen storage tanks  12  and  14  that can be charged to at least 500 PSI, if required. Charge pressure determines run time at any given current draw with a fixed volume. Mathematical modeling shows that higher pressures are possible if desired for the illustrated implementation, or the wall thickness could be reduced to reduce weight of the PEMERY™ battery. The two inertial arms  60  are shown in  FIG. 8   a  with the baffles  16  removed for clarity, and are illustrated in their home positions. The two gas charging ports  34  and the two distribution manifolds  38  and  40  are also shown. The inertial arms  60  are constructed to swing about the pivot axis  56  so as to bring the piercing point  64  into contact with the respective valves or manifolds  38  and  40 . The inertial arms are caused to swing to pierce the valves or manifolds  38  and  40  by force on the apparatus, such as by rotational force or axial force. This may be the result of the firing or launching of a projectile containing the present fuel cell. By piercing the valves  38  and  40 , gas contained in the compartments is permitted access to the fuel cell membrane, activating the fuel cell. The fuel cell assembly with the baffles  16  in place is shown in  FIG. 8   b . The positions of the inertial switches  50  to the valves  38  and  40  so that opening of the valves by the switches  50  supplies the stored gas to the membrane electrode assemblies  70  is also evident in the cross-section of the PEMERY™ battery. The apparatus is enclosed win a housing  102 . The overall configuration of the housing of the illustrated embodiment is a flattened disc, although other configurations and shapes are possible. 
     In order to create an operational fuel cell to meet the requirements of the present embodiment, or other possible embodiments, various other components such as gas diffusers, current collectors, conductors, and sealants, are required. Many of these items are off the shelf, although there may be some adjustments made to work in this application. The innovative aspects of the present invention are embodied in the shape of the membrane electrode assemblies  70  and the gas diffusion manifolds  38  and  40 , as well as keeping the hydrogen gas on one side and the oxygen gas on the other side of the storage tank  10 . 
     As some of the potential environments for use of the present invention involve different types of motion, the balance of the fuel cell becomes a factor in the performance of the desired application. For example, in an ordnance environment, the fuel cell may be subjected to a high RPM spinning action during post-launch. Thus, extra caution must be taken with the physical design of the fuel cell to create a well-balanced construction. 
     While the invention has been described in an ordnance environment, it should not be limited to use in only that type of application. This invention can be provide a compact power source in a variety of environments, such as personal safety alarms, emergency or investigatory tracking devices, deep space and undersea exploration, and any other application requiring a compact source of energy. The invention is capable of remaining dormant for long periods of time prior to use, but the application of the invention should not be limited to only those in which the potential for dormancy exists, as the fuel cell can also be used immediately. 
     Upon careful reviewing of the foregoing specification and drawings, it will be evident that this invention may be implemented with any modifications, combinations and alterations in a number of ways which may differ from those set forth. The particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of any claims associated herewith and all equivalents thereof.