Button cell having winding electrode and method for the production thereof

Abstract

A button cell includes a metal cell cup, a cell top, a first electrode, and a second electrode. The first electrode includes a first current collector having an active material-free region, and the second electrode includes a second current collector. The button cell further includes a first metal foil conductor having a first portion attached to the active material-free region of the first current collector and an insulator applied to a rear side of the first metal foil conductor along a second portion of the first metal foil conductor. The first electrode and the second electrode form, along with a first separator layer and a second separator layer, an electrode assembly that is wound in a spiral to form an electrode winding. The second portion of the first metal foil conductor is welded to one of the metal cell cup or the cell top.

What is claimed is: 
     
         1 . A method for producing a button cell, the method comprising:
 providing a metal cell cup;   providing a cell top;   providing a first electrode, the first electrode including a first current collector partially coated with a first active electrode material and having an active material-free region;   providing a second electrode, the second electrode including a second current collector at least partially coated with a second active electrode material;   attaching a first portion of a first metal foil conductor to the active material-free region of the first current collector;   after attaching the first portion of the first metal foil conductor to the active material-free region of the first current collector, applying an insulator to:
 a rear side of the first metal foil conductor along a second portion of the first metal foil conductor, and 
 (i) a rear side of the first metal foil conductor along the first portion of the first metal foil conductor and/or (ii) a portion of the active material-free region of the first current collector to which the first portion of the first metal foil conductor is attached; 
   forming an electrode winding by winding, in a spiral, an electrode assembly, the electrode assembly including:
 the first electrode, 
 a first separator layer, 
 the second electrode, and 
 a second separator layer, 
   welding the second portion of the first metal foil conductor to a first housing part, wherein the first housing part is one of the metal cell cup or the cell top; and   assembling the metal cell cup and the cell top to form a housing in which the electrode winding is disposed.   
     
     
         2 . The method of  claim 1 , further comprising applying a further insulator to (i) the portion of the active material-free region of the first current collector to which the first portion of the first metal foil conductor is attached and/or (ii) a front side of the first metal foil conductor along the first portion of the first metal foil conductor. 
     
     
         3 . The method according to  claim 1 , wherein the first metal foil conductor extends out of the electrode winding from a first end face of the electrode winding, the method further comprising:
 folding the first metal foil conductor towards the rear side of the first metal foil conductor such that the second portion of the first metal foil conductor bears flat on the first end face of the electrode winding with the insulator disposed between the second portion of the first metal foil conductor and the first end face of the electrode winding.   
     
     
         4 . The method according to  claim 3 , wherein the electrode winding includes an axial cavity, and
 wherein the second portion of the first metal foil conductor overlaps with an opening of the axial cavity.   
     
     
         5 . The method according to  claim 4 , wherein a winding core is disposed in the axial cavity, and
 wherein the second portion of the first metal foil conductor overlaps with an axial end side of the winding core.   
     
     
         6 . The method according to  claim 4 , wherein the second portion of the first metal foil conductor is welded to the first housing part in a region of the first housing part that overlaps the axial cavity. 
     
     
         7 . The method according to  claim 3 , wherein the first metal foil conductor is a metal foil strip having (i) first and second longitudinal edges extending along a length of the metal foil strip, including the first portion and the second portion of the first metal foil conductor, and (ii) a terminal edge disposed at the end of the second portion of the first metal foil conductor and connecting the first and second longitudinal edges, and
 wherein the insulator extends, along the first end face of the electrode winding, both (i) beyond the terminal edge of the metal foil strip in a direction along which the first and second longitudinal edges extend and (ii) beyond both the first and second longitudinal edges of the metal foil strip in a second direction along which the terminal edge extends.   
     
     
         8 . The method according to  claim 1 , wherein the insulator is a first insulating tape, and wherein the applying the insulator comprises adhesively bonding the insulator to:
 a rear side of the first metal foil conductor along the second portion of the first metal foil conductor, and   (i) a rear side of the first metal foil conductor along the first portion of the first metal foil conductor and/or (ii) a portion of the active material-free region of the first current collector to which the first portion of the first metal foil conductor is attached.   
     
     
         9 . The method according to  claim 8 , wherein attaching the first portion of the first metal foil conductor to the active material-free region of the first current collector comprises welding the first portion of the first metal foil conductor to the active material-free region of the first current collector. 
     
     
         10 . The method according to  claim 1 , further comprising:
 attaching a first portion of a second metal foil conductor to an active material-free region of the second current collector, wherein the second metal foil conductor extends out of the electrode winding from a second end face of the electrode winding;   after attaching the first portion of the second metal foil conductor to the active material-free region of the second current collector, applying a second insulator to:
 a rear side of the second metal foil conductor along a second portion of the second metal foil conductor, and 
 (i) a rear side of the second metal foil conductor along the first portion of the second metal foil conductor and/or (ii) a portion of the active material-free region of the second current collector to which the first portion of the second metal foil conductor is attached; and 
   folding the second metal foil conductor towards the rear side of the second metal foil conductor such that the first portion of the second metal foil conductor bears flat on the second end face of the electrode winding with the second insulator disposed between the first portion of the second metal foil conductor and the second end face of the electrode winding.   
     
     
         11 . A button cell, comprising:
 a metal cell cup;   a cell top;   a first electrode, the first electrode including a first current collector partially coated with a first active electrode material and having an active material-free region;   a second electrode, the second electrode including a second current collector at least partially coated with a second active electrode material;   a first metal foil conductor having a first portion attached to the active material-free region of the first current collector;   an insulator applied to:
 a rear side of the first metal foil conductor along a second portion of the first metal foil conductor, and 
 (i) a rear side of the first metal foil conductor along the first portion of the first metal foil conductor and/or (ii) a portion of the active material-free region of the first current collector to which the first portion of the first metal foil conductor is attached; 
   wherein first electrode and the second electrode form, along with a first separator layer and a second separator layer, an electrode assembly that is wound in a spiral to form an electrode winding,   wherein the second portion of the first metal foil conductor is welded to a first housing part, wherein the first housing part is one of the metal cell cup or the cell top; and   wherein the metal cell cup and the cell top form a housing in which the electrode winding is disposed.   
     
     
         12 . The button cell according to  claim 11 , further comprising a further insulator applied to (i) the portion of the active material-free region of the first current collector to which the first portion of the first metal foil conductor is attached and/or (ii) a front side of the first metal foil conductor along the first portion of the first metal foil conductor. 
     
     
         13 . The button cell according to  claim 11 , wherein the first metal foil conductor extends out of the electrode winding from a first end face of the electrode winding, and
 wherein the first metal foil conductor is folded towards the rear side of the first metal foil conductor such that the second portion of the first metal foil conductor bears flat on the first end face of the electrode winding with the insulator disposed between the second portion of the first metal foil conductor and the first end face of the electrode winding.   
     
     
         14 . The button cell according to  claim 13 , wherein the electrode winding includes an axial cavity, and
 wherein the second portion of the first metal foil conductor overlaps with an opening of the axial cavity.   
     
     
         15 . The button cell according to  claim 14 , wherein a winding core is disposed in the axial cavity, and
 wherein the second portion of the first metal foil conductor overlaps with an axial end side of the winding core.   
     
     
         16 . The button cell according to  claim 14 , wherein the second portion of the first metal foil conductor is welded to the first housing part in a region of the first housing part that overlaps the axial cavity. 
     
     
         17 . The button cell according to  claim 13 , wherein the first metal foil conductor is a metal foil strip having (i) first and second longitudinal edges extending along a length of the metal foil strip, including the first portion and the second portion of the first metal foil conductor, and (ii) a terminal edge disposed at the end of the second portion and connecting the first and second longitudinal edges, and
 wherein the insulator extends, along the first end face of the electrode winding, both (i) beyond the terminal edge of the metal foil strip in a direction along which the first and second longitudinal edges extend and (ii) beyond both the first and second longitudinal edges of the metal foil strip in a second direction along which the terminal edge extends.   
     
     
         18 . The button cell according to  claim 1 , wherein the insulator is a first insulating tape adhesively bonded to:
 a rear side of the first metal foil conductor along a second portion of the first metal foil conductor, and   (i) a rear side of the first metal foil conductor along the first portion of the first metal foil conductor and/or (ii) a portion of the active material-free region of the first current collector to which the first portion of the first metal foil conductor is attached.   
     
     
         19 . The button cell according to  claim 11 , wherein the first portion of the first metal foil conductor is welded to the active material-free region of the first current collector. 
     
     
         20 . The button cell according to  claim 11 , further comprising:
 a second metal foil conductor having a first portion attached to an active material-free region of the second current collector, wherein the second metal foil conductor extends out of the electrode winding from a second end face of the electrode winding;   a second insulator applied to:
 a rear side of the second metal foil conductor along a second portion of the second metal foil conductor, and 
 (i) a rear side of the second metal foil conductor along the first portion of the second metal foil conductor and/or (ii) a portion of the active material-free region of the second current collector to which the first portion of the second metal foil conductor is attached, 
   wherein the second metal foil conductor is folded towards the rear side of the second metal foil conductor such that the first portion of the second metal foil conductor bears flat on the second end face of the electrode winding with the insulator disposed between the first portion of the second metal foil conductor and the second end face of the electrode winding.