Abstract:
A fuel cell pack comprising a plurality of fuel cells and means internal of said pack for holding the cells together.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to fuel cells and, in particular, to fuel cells to be arranged in stack form. 
     In the design of fuel cell stacks, it would be advantageous if the fuel cells to be employed in the stack could be arranged in packs or units capable of independent handling. Fuel cell packs of this type would simplify the assembly procedure of an overall stack and, furthermore, would greatly facilitate maintenance and repair of the stack during operation. 
     One technique for providing individual fuel cell packs would be to use mechanical connectors external of the individual cells to connect the cells together much the same way as larger fuel cell stacks are now formed. However, this type of technique would require a significant number of mechanical connectors which would make the pack cumbersome, bulky and difficult to handle. 
     It is therefore an object of the present invention to provide a fuel cell pack which does not suffer from the above disadvantages. 
     It is a further object of the present invention to provide a fuel cell pack which is of relatively simple construction and which can be easily assembled with and disassembled from similar fuel cell packs. 
     SUMMARY OF THE PRESENT INVENTION 
     In accordance with the principles of the present invention, the above and other objectives are realized in a fuel cell pack comprising a plurality of fuel cells arranged in adjacent relationship and means internal of the pack for connecting the cells together. 
     By utilizing internal means for cell interconnection, the pack of the invention can be easily assembled with other packs to form a composite fuel cell stack. Furthermore, disassembly of the packs is now also facilitated so that individual cells can be repaired simply by removing their corresponding pack from the stack. 
     In the embodiment of the invention to be disclosed hereinafter various internal means for carrying out the invention are disclosed. In particular, both chemical means and mechanical means are described. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other features and aspects of the present invention will become more apparent upon reading the following detailed description in conjunction with the accompanying sole drawing which illustrates a fuel cell pack in accordance with the principles of the present invention. 
    
    
     DETAILED DESCRIPTION 
     In the FIGURE, a fuel cell pack 1 in accordance with the principles of the present invention is shown. The pack 1 comprises four bipolar plates 3 and two end cooling plates 4. The plates 3 have channels 3a in their opposing surfaces for carrying process gases. The plates 4, in turn, have channels 4a in their inner surfaces facing toward the pack for carrying such gases and channels 4b in their outer surfaces facing away from the pack for carrying cooling gases. 
     Sandwiched between adjacent plates are respective anode electrode, cathode electrode and electrolyte matrix composites 5 and possibly spacers or shims. Each composite along with its adjacent plates form a fuel cell 2 so that in the present case the pack 1 contains five cells. 
     In accordance with the invention, the pack 1 is further provided with means internal of the pack for connecting the fuel cells 2 together. More particularly, as illustrated, a plurality of through passages 6 extend through the stack and are adapted to receive either mechanical and/or chemical means for interconnecting the cells 2. Thus, a friction fitting plug 7 or other similar internal mechanical fastener such as, for example, a dowel pin, rivet, screw or bolt, may be inserted in the passages 6 to thereby hold the fuel cells together. Alternatively, a high-strength adhesive material 8 such as, for example, Chem-grip HT, may be situated in the passages 6 and cured therein to provide the interconnecting bond. 
     The internal connecting means may take other forms which can be used alone or in combination with the through passages 6 and connectors therein. In particular, the connecting means may be disposed between facing surfaces of selected adjacent elements in each cell and selected adjacent elements of successive cells. Thus, for example, high strength adhesive strips 9 can be placed on the peripheral areas of adjacent plates 3 and 4 to provide interconnection of the cells 2 similar to interconnection achieved with the passages 6. As mentioned, if desired for greater strength, the two forms of interconnecting means may be used. 
     With the cell pack 1 fabricated as above-described, the cell pack is free of external connectors which are often cumbersome and tend to obstruct operation. Furthermore, the pack can now be easily pretested and readily assembled with other pretested packs to form a composite fuel cell stack. Pretesting the packs provides an increased assurance of stack performance. In fact, the increased assurance can be made to approach that realizable by the testing of each cell individually which itself is impractical if not impossible to carry out. 
     The packs of the invention also facilitate testing of the composite stack since the packs can now be individually scanned to locate a problem area. Furthermore, maintenance and repair are also facilitated, since an inoperative pack, once located by scanning, can be removed from the stack and replaced by another pretested pack. A composite stack which otherwise might not have been salvagable is thus made so by utilization of the cell packs of the invention. Considerable savings in time, labor and expense is thus realized. 
     In all cases, it is understood that the abovedescribed arrangements are merely illustrative of the many possible specific embodiments which represent applications of the present invention. Numerous and varied other arrangements can readily be devised in accordance with the principles of the present invention without departing from the spirit and scope of the invention.