Electrochemical Cell with Improved Internal Contact

Abstract

Electrochemical battery cells with strip-like electrodes and having a pressure contact between a lead from one of the electrodes and a sidewall of the cell container. An electrochemical cell having a spiral wound electrode assembly having an internal lead in direct pressure contact with a lithium foil negative electrode free of a separate current collector and in contact with an inner portion of the cell container, wherein specified contact between the lead and lithium foil provides current flow between the container and foil.

1 . An electrochemical cell, comprising:
 a substantially cylindrical, conductive container having a closed end, an open end sealed by an end assembly, and a sidewall extending between the closed end and the open end;   a positive electrode comprising iron disulfide;   a negative electrode having a length, a width and a cumulative surface area consisting essentially of lithium or a lithium alloy having at least 90 wt. % lithium and wherein the negative electrode does not include a current collector disposed substantially along the cumulative surface area of the negative electrode;   a separator;   a nonaqueous, organic electrolyte;   an internal lead located in the container and in electrical contact with the negative electrode, wherein the lead has a surface area that is connected to less than 0.7% of the cumulative surface area of the negative electrode, and   wherein the positive electrode, the negative electrode and the separator are wound into a jellyroll electrode assembly so that the internal lead makes electrical contact with the container or the end assembly; and   wherein an interfacial, theoretical anode-to-cathode input capacity ratio for the cell is less than 1.0.   
     
     
         2 . The electrochemical cell according to  claim 1 , wherein the lead surface area in contact with the negative electrode is less than 0.5%. 
     
     
         3 . The electrochemical cell according to  claim 1 , wherein the lead has a resistance of less than 15 mΩ/cm length. 
     
     
         4 . The electrochemical cell according to  claim 3 , wherein the lead is nickel plated cold rolled steel, nickel, a nickel alloy, copper, a copper alloy, or stainless steel. 
     
     
         5 . The electrochemical cell according to  claim 1 , wherein the lead has an area from 5.0 mm 2  to 160 mm 2  in contact with the surface of the negative electrode. 
     
     
         6 . The electrochemical cell according to  claim 1 , wherein the lead surface area in contact with the negative electrode is between 0.02% and 0.5%, and wherein the interfacial, theoretical anode-to-cathode input capacity ratio is less than 0.95. 
     
     
         7 . The electrochemical cell according to  claim 1 , wherein the interfacial, theoretical anode-to-cathode input capacity ratio is less than 0.95. 
     
     
         8 . The electrochemical cell according to  claim 1 , wherein the interfacial, theoretical anode-to-cathode input capacity ratio is between 1.0 and 0.95. 
     
     
         9 . The electrochemical cell according to  claim 1 , wherein the lead extends a distance measured from one width end of the negative electrode from 10% to less than 88% of the width of the lithium or lithium alloy layer measured parallel to a longitudinal axis of the cell at a location of connection. 
     
     
         10 . The electrochemical cell according to  claim 9 , wherein the lead extends a distance measured from one width end of the negative electrode from 10% to 60% of the width of the lithium or lithium alloy layer, and wherein a interfacial, theoretical anode-to-cathode input capacity ratio for the cell is less than 0.95. 
     
     
         11 . The electrochemical cell according to  claim 9 , wherein the lead extends a distance measured from one width end of the negative electrode from 10% to 50% of the width of the lithium or lithium alloy layer. 
     
     
         12 . The electrochemical cell according to  claim 1 , wherein the lead has an area from 5.0 mm 2  to 160 mm 2  in contact with a surface of the negative electrode. 
     
     
         13 . The electrochemical cell according to  claim 12 , wherein the lead has an area from 10.0 mm 2  to 92.6 mm 2  in contact with the surface of the negative electrode, and wherein the interfacial, theoretical anode-to-cathode input capacity ratio is less than 0.95. 
     
     
         14 . The electrochemical cell according to  claim 1 , wherein the lead has a resistance of less than 5mΩ/cm length, and wherein the lead is nickel plated cold rolled steel, nickel, a nickel alloy, copper, a copper alloy, or stainless steel.