Method of fabricating an electrochemical cell battery and an improved cell package

Abstract

A method of manufacturing an electrochemical battery where the electrolyte is introduced into the cell stack with minimal or no loss of electrolyte. The method of fabricating the battery, comprises the steps of separately forming an electrode cell stack and a sealed electrolyte pouch, placing the cell stack and the electrolyte pouch together into a cell package, applying a vacuum to the cell package, sealing the cell package, and rupturing the pouch to release the electrolyte into the cell stack. The pouch is ruptured by squeezing the pouch until the electrolyte squirts out of the pouch. Also, the cell package is sealed by heat sealing. With this fabrication technique there is little or no electrolyte loss. In particular, since the electrolyte is injected into the electrode cell stack after the package has been sealed, substantially all of the electrolyte is suctioned into the electrode cell stack without any of the electrolyte escaping from the package. In addition, since the electrolyte is not poured into the cell stack during the manufacturing of the cell stack, the cell manufacturing machine does not have to provide a glove box environment. Also, contamination of the cell stack manufacturing machine is avoided. The cell package is made of a laminate of polyester, aluminum and polypropylene to allow the heat sealing of the polypropylene layers to each other even when the cell package is contaminated with electrolyte. Accordingly, it is not necessary to transfer the cell stack to an uncontaminated cell package.

What is claimed is:  
     
         1 . A method of fabricating an electrochemical battery, comprising the following steps: 
 forming an electrode cell stack and an enclosure;    placing said cell stack and a sealed electrolyte pouch together into said enclosure;    applying a vacuum to said enclosure;    sealing said enclosure; and    rupturing said pouch to release said electrolyte into said cell stack.    
     
     
         2 . The method of fabricating an electrochemical battery according to  claim 1 , wherein said step of forming said enclosure includes the step of forming a cell package.  
     
     
         3 . The method of fabricating an electrochemical battery according to  claim 2 , wherein said sealing step includes the step of heat sealing said cell package.  
     
     
         4 . The method of fabricating an electrochemical battery according to  claim 2 , wherein said step of forming said cell package comprises the step of forming first and second parts each comprising a laminate of polyester, aluminum and polypropylene, and wherein said sealing step includes the step of heat sealing said polypropylene layers of said first and second parts to one another.  
     
     
         5 . The method of fabricating an electrochemical battery according to  claim 1 , wherein said rupturing step includes the step of squeezing said pouch.  
     
     
         6 . The method of fabricating an electrochemical battery according to  claim 1 , wherein said sealing step includes the step of heat sealing said enclosure.  
     
     
         7 . A method of fabricating an electrochemical battery, comprising the following steps: 
 forming an electrode cell stack;    injecting an electrolyte into a pouch through an open end;    sealing said open end of said pouch in a vacuum state;    placing said sealed pouch and said electrode cell stack into an enclosure;    applying a vacuum to said enclosure; and    rupturing said pouch to release said electrolyte into said electrode cell stack.    
     
     
         8 . The method of fabricating an electrochemical battery according to  claim 7 , wherein said enclosure is a cell package.  
     
     
         9 . The method of fabricating an electrochemical battery according to  claim 7 , wherein said rupturing step includes the step of squeezing said pouch.  
     
     
         10 . The method of fabricating an electrochemical battery according to  claim 7 , wherein said sealing step includes the step of heat sealing said enclosure.  
     
     
         11 . The method of fabricating an electrochemical battery according to  claim 8 , wherein said sealing step includes the step of heat sealing said cell package.  
     
     
         12 . The method of fabricating an electrochemical battery, comprising the following steps: 
 forming an electrode cell stack;    placing said cell stack and a sealed electrode pouch into a vacuum enclosure; and    rupturing said pouch to fill said electrode cell stack with electrolyte.    
     
     
         13 . The method of fabricating an electrochemical battery according to  claim 12 , wherein said sealed electrode pouch is a vacuum pouch.  
     
     
         14 . A method of fabrication an electrochemical battery, comprising the following steps: 
 forming a cell package having first and second enclosures and including a tube communicating between said first and second enclosures;    placing a cell stack in said first enclosure with leads of said cell stack protruding from said first enclosure and sealing and evacuating said first enclosure;    placing an evacuated electrolyte pouch in said second enclosure and sealing and evacuating said enclosure;    rupturing said pouch such that electrolyte flows from said pouch, through said tube and into said cell stack; and    sealing said tube.    
     
     
         15 . The method of  claim 14 , further comprising the step of removing said second enclosure after said sealing step.  
     
     
         16 . The method of  claim 15 , further comprising, after said rupturing step and before said sealing step, the steps of subjecting said cell package to formation and thereafter puncturing said second enclosure and applying a vacuum to said second enclosure to degas said first enclosure.  
     
     
         17 . A method of fabrication an electrochemical battery, comprising the following steps: 
 forming a cell package having an enclosure and including a tube having one end communicating with said enclosure and an opposite end extending from said cell package;    placing a cell stack in said enclosure with leads of said cell stack protruding from said enclosure and sealing and evacuating said first enclosure;    introducing electrolyte into said opposite end of said tube such that said electrolyte enters said enclosure and said cell stack; and    sealing said tube.    
     
     
         18 . An electrochemical cell comprising: 
 a casing; and    an electrode cell stack contained within said casing along with an electrolyte, wherein said casing includes first and second parts each comprising a laminate having an outer layer, an inner layer and a barrier layer interposed between said inner and outer layers, said first and second parts having their inner layers adhered to one another, said inner layer being a polypropylene layer, wherein said inner layer and said barrier layer are adhered together with an adhesive, said adhesive being one of a thermoset polyurethane adhesive or an organosol type modified polypropylene dispersion adhesive.    
     
     
         19 . The electrochemical cell of  claim 18 , wherein said outer layer is a polyester layer and said barrier layer is an aluminum layer.  
     
     
         20 . The electrochemical cell of  claim 18 , wherein said polypropylene inner layers are heat sealed to each other.  
     
     
         21 . The electrochemical cell of  claim 19 , wherein said polypropylene inner layers are heat sealed to each other.  
     
     
         22 . The electrochemical cell of  claim 18 , wherein said first and second parts are unitary with each other.  
     
     
         23 . The electrochemical cell of  claim 18 , wherein said first and second parts are initially independent of each other and are heat sealed to each other around the entire periphery thereof.  
     
     
         24 . The electrochemical cell of  claim 21 , wherein said casing initially includes a first portion in which said cell stack is located and a removable second portion in which an electrolyte pouch is receivable for impregnating said electrodes with said electrolyte upon the bursting of said pouch.