Reinforced coiled electrode assemblies and methods of producing same

Abstract

The present invention relates to coiled electrode assemblies having conductive tabs, methods of attaching the conductive tabs to the coiled electrode, and electrochemical cells employing such assemblies. An electrode plate which is coated with active material has a designated area for tab attachment. The conductive tab area's active material is pierced with opposing, offset piercing plates which have raised surface probes which penetrate the conductive tab area's coating and substrate. This tab area is cleared of active material and reinforced with a reinforcing material and a conductive tab is welded to the thus treated area resulting in an electrode plate having a strong integrated tab assembly.

What is claimed is:  
     
         1 . A method of producing an electrode plate having a conductive tab area comprising the steps of: 
 (a) piercing an area of an electrode plate with opposing, offset piercing plates having raised surface probes;    (b) clearing the resulting area to expose a porous substrate forming a conductive tab area;    (c) reinforcing the exposed porous substrate; and    (d) attaching a conductive tab to the reinforced porous substrate.    
     
     
         2 . The method of    claim 1   , wherein the reinforcing step comprises placing a reinforcing material over the exposed porous substrate.  
     
     
         3 . The method of    claim 2   , wherein the reinforcing step further comprises compressing the reinforcing material into the exposed porous substrate.  
     
     
         4 . The method of    claim 3   , wherein the reinforcing material is double ply.  
     
     
         5 . The method of    claim 3   , wherein the attaching step includes applying ultrasonics.  
     
     
         6 . The method of    claim 5   , wherein the ultrasonics include an ultrasonic horn having raised surfaces and an anvil having a flat surface.  
     
     
         7 . The method of    claim 3   , wherein the attaching step includes resistance welding.  
     
     
         8 . The method of    claim 7   , further comprising the step of applying ultrasonics to the reinforcing material compressed into the exposed porous substrate prior to the attaching step.  
     
     
         9 . The method of    claim 1   , further comprising the step of punching a hole in the conductive tab after the attaching step.  
     
     
         10 . The method of    claim 1   , further comprising the step of taping the conductive tab and conductive tab area after the attaching step.  
     
     
         11 . The method of    claim 1   , wherein the clearing step includes applying ultrasonics to the resulting area.  
     
     
         12 . The method of    claim 11   , wherein the ultrasonics are applied by an ultrasonic horn having a smooth surface and an anvil having raised surfaces.  
     
     
         13 . The method of    claim 1   , wherein the conductive tab is a single layer conductive tab.  
     
     
         14 . The method of    claim 1   , wherein the conductive tab is a double layer conductive tab.  
     
     
         15 . A method of producing an electrode plate having a conductive tab area comprising the steps of: 
 (a) placing a reinforcing material over a porous substrate; and    (b) attaching a conductive tab to the reinforcing material over the porous substrate.    
     
     
         16 . The method of    claim 15   , further comprising the step of compressing the reinforcing material into the porous substrate.  
     
     
         17 . The method of    claim 16   , further comprising the step of piercing an area of an electrode plate with opposing, offset piercing plates having raised surface probes and clearing the resulting area to expose the porous substrate forming a conductive tab area prior to the placing step.  
     
     
         18 . The method of    claim 15   , wherein the attaching step includes applying ultrasonics.  
     
     
         19 . The method of    claim 15   , wherein the attaching step includes resistance welding.  
     
     
         20 . The method of    claim 19   , further comprising the step of applying ultrasonics to the reinforcing material placed over the porous substrate prior to the attaching step.  
     
     
         21 . The method of    claim 15   , further comprising the step of punching a hole in the conductive tab after the attaching step.  
     
     
         22 . The method of    claim 15   , further comprising the step of taping the conductive tab and conductive tab area after the attaching step.  
     
     
         23 . An electrode plate having an underlying porous substrate coated with an electrochemically active material, wherein the electrode plate comprises a conductive tab area substantially free of the active material and a conductive tab attached to the conductive tab area, and a reinforcing material between the conductive tab and the conductive tab area.  
     
     
         24 . An electrochemical cell comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the positive electrode comprises an electrode plate having an underlying porous substrate coated with an electrochemically active material, wherein the electrode plate has a conductive tab area substantially free of the active material and a conductive tab attached to the conductive tab area, and a reinforcing material between the conductive tab and the conductive tab area.