Carbon fabric supercapacitor structure

Abstract

Supercapacitor cell electrode ( 13, 17 ) and separator ( 15 ) elements are fabricated from activated carbon fabric and membranes of microporous fibrillar ultra-high molecular weight polyethylene and are laminated with electrically conductive current collector elements ( 11, 19 ) to form a flexible, unitary supercapacitor structure ( 10 ). The micro-fibrillar laminar structure of the separator membrane material enables direct application of cell lamination temperatures without resulting collapse of separator microporosity and attendant loss of essential electrolyte retention and ionic conductivity. The superior functional materials enable the fabrication of flexible, self-supporting cell structures which yield improved specific energy capacity and increased voltage output for utilization demands.

What is claimed is:  
     
         1 . A supercapacitor structure comprising in contiguity a positive electrode member, a negative electrode member, and a separator member interposed therebetween characterized in that 
 a) each of said electrode members comprises an activated carbon fabric element to which is bonded an electrically-conductive current collector element,    b) said separator member comprises a micro-fibrillar ultra-high molecular weight polyolefin membrane, and    c) each said member is bonded to one or more contiguous members at its respective interface to form a unitary flexible laminate structure.    
     
     
         2 . A supercapacitor structure according to  claim 1  wherein said polyolefin membrane comprises polyethylene.  
     
     
         3 . A supercapacitor structure according to  claim 1  wherein at least one of said collector elements comprises an open-mesh grid.  
     
     
         4 . A supercapacitor structure according to  claim 3  wherein said collector element grids are thermally bonded to associated carbon fabric by an electrically-conductive thermoadhesive composition.  
     
     
         5 . A supercapacitor structure according to  claim 4  wherein said carbon fabric electrode elements are thermally bonded to the interposed separator member by virtue of the thermoadhesive nature of said polyolefin membrane.  
     
     
         6 . A method of making a supercapacitor structure which comprises arranging contiguously a positive electrode member, a negative electrode member, and a separator member interposed therebetween characterized in that 
 a) each of said electrode members is formed of an activated carbon fabric element bonded to an electrically-conductive current collector element,    b) said separator member is formed of a micro-fibrillar ultra-high molecular weight polyolefin membrane, and    c) each said member is bonded to one or more contiguous members at its respect interface to form a unitary flexible laminate structure.    
     
     
         7 . A method according to  claim 6  wherein 
 a) at least one surface of each said collector element is coated with a layer of electrically-conductive thermoadhesive composition,  
 b) each fabric electrode element is arranged in surface contact with the coated surface of its associated collector element to form a subassembly, and  
 c) said subassembly is laminated under heat and pressure to form a unitary electrode member.  
 
     
     
         8 . A method according to  claim 7  wherein 
 a) the exposed fabric surface of each said electrode member is arranged in contact with a respective surface of said separator member, and  
 b) said arrangement is laminated under heated and pressure to soften at least said separator member surfaces and effect an adhesive laminate bond between said members.