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 side wall 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 an a width consisting essentially of lithium or a lithium alloy having at least 90 wt. % lithium and having a cumulative surface area;   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 a theoretical, interfacial 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 theoretical, interfacial anode-to-cathode input capacity ratio is less than 0.95. 
     
     
         7 . The electrochemical cell according to  claim 1 , wherein there is no direct electrical contact between the sidewall of the container and either the negative electrode or the positive electrode contact. 
     
     
         8 . The electrochemical cell according to  claim 7 , wherein the lead is connected to a bottom portion of the negative electrode, extends around a bottom end of an outer wind of the electrode assembly, and is in pressure contact with the sidewall or a bottom wall of the container. 
     
     
         9 . The electrochemical cell according to  claim 7 , wherein the surface area in contact with the negative electrode is between 0.02% and 0.5%. 
     
     
         10 . 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 spiral wound electrode assembly disposed within the container and including a negative electrode, positive electrode, an organic nonaqueous electrolyte, and a separator disposed between the negative electrode and positive electrode, wherein the negative electrode consists essentially of one or more layers of lithium or a lithium alloy having a length and a width, and wherein the negative electrode is free of a separate current collector; and   an internal lead located in the container and electrically connecting the negative electrode to the container, wherein one end portion of the lead is directly connected to the one or more layers of lithium or lithium alloy, and 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.   
     
     
         11 . The electrochemical cell according to  claim 10 , 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 theoretical, interfacial anode-to-cathode input capacity ratio for the cell is less than 1.0. 
     
     
         12 . The electrochemical cell according to  claim 11 , 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, and wherein the lead has a resistance of less than 15 mΩ/cm length. 
     
     
         13 . The electrochemical cell according to  claim 11 , wherein the lead has an area from 5.0 mm 2  to 160 mm 2  in contact with a surface of the negative electrode. 
     
     
         14 . The electrochemical cell according to  claim 13 , wherein the lead is connected to a bottom portion of the negative electrode, extends around a bottom end of an outer wind of the electrode assembly, and is in pressure contact with the sidewall or a bottom wall of the container. 
     
     
         15 . The electrochemical cell according to  claim 14 , 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 theoretical, interfacial anode-to-cathode input capacity ratio is less than 0.95. 
     
     
         16 . The electrochemical cell according to  claim 10 , wherein the lead has a resistance of less than 5 mΩ/cm length, and wherein the lead is nickel plated cold rolled steel, nickel, a nickel alloy, copper, a copper alloy, or stainless steel. 
     
     
         17 . The electrochemical cell according to  claim 16 , wherein the separator or a cover wrap, or a combination thereof is present on an outside surface of the electrode assembly such that there is no direct negative electrode or positive electrode contact with the container sidewall. 
     
     
         18 . 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 spiral wound electrode assembly disposed within the container, said spiral wound electrode assembly having a negative electrode strip consisting essentially of lithium or a lithium alloy with a length and a width creating a cumulative surface area, a positive electrode strip, an organic nonaqueous electrolyte, and a separator disposed between the negative and positive electrode strips;   an internal lead located in the container and electrically connecting the negative electrode to the container, wherein one end portion of the lead is connected to the lithium or lithium alloy;   wherein there is no direct electrical contact between the sidewall of the container and either the negative electrode or the positive electrode;   wherein the lead is connected along a bottom portion of the negative electrode and extends outside the electrode assembly to make pressure contact with the sidewall or a bottom wall of the container; and   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 extends a distance measured from one width end of the negative electrode from 10% to less than 88% of the width of the negative electrode as measured parallel to a longitudinal axis of the cell.   
     
     
         19 . The electrochemical cell according to  claim 18 , wherein the surface area is connected to 0.02% to 0.5% of the cumulative surface area, and wherein the theoretical, interfacial anode-to-cathode input capacity ratio is less than 0.95. 
     
     
         20 . The electrochemical cell according to  claim 19 , wherein the lead has an area of 5.0 mm 2  to less than 160 mm 2  in contact with the surface of the negative electrode, and wherein the lead is in non-welded electrical contact with the container.