Flexible Thin Printed Battery and Device and Method of Manufacturing Same

Abstract

A flat, flexible electrochemical cell is provided. The within invention describes various aspects of the flat, flexible electrochemical cell. A printed anode is provided that obviates the need for a discrete anode current collector, thereby reducing the size of the battery. An advantageous electrolyte is provided that enables the use of a metallic cathode current collector, thereby improving the performance of the battery. Printable gelled electrolytes and separators are provided, enabling the construction of both co-facial and co-planar batteries. Cell contacts are provided that reduce the potential for electrolyte creepage in the flat, flexible electrochemical cells of the within invention.

1 . A flat battery comprising:
 a first substrate having an inner surface and an outer surface;   a cathode applied on said first substrate;   a zinc ink anode applied on said first substrate such that said anode and said cathode are substantially co-planar;   an electrolyte in contact with both said anode and said cathode, said electrolyte comprising an additive to prevent or reduce gassing; and   a second substrate secured to said first substrate thereby defining a cell volume between them that is isolated from an ambient environment;   said electrolyte and at least major proportions of said cathode and said zinc ink anode being contained within said cell volume.   
     
     
         2 . The flat battery of  claim 1 , said zinc ink anode being printed on said inner surface of said first substrate. 
     
     
         3 . The flat battery of  claim 2 , said zinc ink anode being printed from a zinc ink comprising zinc powder, a binder and a solvent, said zinc powder being a zinc alloy comprising bismuth, said electrolyte being an aqueous acidic electrolyte comprising zinc chloride. 
     
     
         4 . The flat battery of  claim 3 , said zinc powder being a zinc alloy of bismuth, indium and aluminum. 
     
     
         5 . The flat battery of  claim 3 , said zinc powder having a particle size d(50) value of 10-60 microns. 
     
     
         6 . The flat battery of  claim 1 , said zinc ink anode being printed from a zinc ink comprising zinc powder, a binder and an aqueous solvent, and said binder comprising polyvinylpyrrolidone having a molecular weight of 2 million to 4 million. 
     
     
         7 . The flat battery of  claim 6 , said aqueous solvent comprising zinc acetate. 
     
     
         8 . The flat battery of  claim 7 , said aqueous solvent further comprising N-methyl pyrrolidone. 
     
     
         9 . The flat battery of  claim 1 , further comprising a cathode current collector printed directly on said inner surface of said first substrate, said cathode current collector comprising a first, metallic layer printed from metallic ink and a second, carbon layer printed over the metallic layer from carbon ink. 
     
     
         10 . The flat battery of  claim 1 , said cathode comprising electrolytic manganese dioxide, graphite and a binder. 
     
     
         11 . The flat battery of  claim 8 , said cathode being printed from a cathode ink that comprises 17.0 to 66.0 weight percent suspended electrolytic manganese dioxide powder and 4.0 to 45.0 weight percent suspended graphite powder in an aqueous solvent. 
     
     
         12 . The flat battery of  claim 8 , said cathode being printed from a cathode ink that comprises 25.0 to 43.0 weight percent suspended electrolytic manganese dioxide and 6.0 to 25.0 weight percent suspended graphite in an aqueous solvent. 
     
     
         13 . The flat batter of  claim 10 , said electrolytic manganese dioxide powder being ground to a d(50) of around 1 micron. 
     
     
         14 . The flat battery of  claim 1 , wherein at least one of the electrodes also comprises an additive to prevent or reduce gassing. 
     
     
         15 . The flat battery of  claim 12 , said anode being a printed zinc anode that is printed from a zinc ink comprising said additive. 
     
     
         16 . The flat battery of  claim 13 , said electrolyte further comprising a gelling agent, said electrolyte being in the form of a gel. 
     
     
         16 . The flat battery of  claim 1 , said first substrate comprising a flexible nonconductive polymer material layer, and a heat sealable layer forming said inner surface. 
     
     
         18 . The flat battery of  claim 15 , further comprising a metal foil layer disposed intermediate said polymer material layer and said heat sealable layer. 
     
     
         19 . The flat battery of  claim 1 , further comprising a cathode current collector printed directly on said inner surface of said first substrate, wherein the cathode is printed directly on said current collector.