Capacitor Seals

Abstract

Electrolytic capacitors may use a canister and a lid to confine an electrolyte and prevent the electrolyte from evaporating during use, and an improved seal between the canister and the lid may be achieved by increasing the surface area of the seal. For example, the surface area of the seal may be increased by changing the shape and/or thickness of the canister edge. For example, the surface area of the seal may be increased by changing the shape of an elastomer layer of the lid and/or adding an annular protuberance at the circumference of the lid. For example, the surface area of the seal may be changed by changing the process for forming the edge during the capacitor sealing.

1 . A capacitor, comprising:
 a canister comprising:
 a shell comprising a groove, 
 a base disposed at a first end of the shell, and 
 an edge of a second end of the shell, wherein the edge comprises a rolled portion; and 
   a lid comprising an elastomer on a first side of the lid and a support surface on a second side of the lid, wherein the lid is located between the groove and the rolled portion, wherein the groove is adjacent to the support surface and the rolled portion is adjacent to the elastomer.   
     
     
         2 . The capacitor of  claim 1 , wherein the rolled portion is rolled away from a longitudinal axis of the shell. 
     
     
         3 . The capacitor of  claim 1 , wherein the rolled portion is rolled towards a longitudinal axis of the shell. 
     
     
         4 . The capacitor of  claim 1 , further comprising a capacitive element disposed in the canister. 
     
     
         5 . The capacitor of  claim 1 , further comprising an electrolyte disposed in the canister. 
     
     
         6 . The capacitor of  claim 1 , wherein the capacitor is rated for between 125 volts and 600 volts. 
     
     
         7 . The capacitor of  claim 1 , wherein the capacitor comprises a capacitance of between 0.5 millifarads and 5 millifarads. 
     
     
         8 . The capacitor of  claim 1 , wherein the canister comprises an aluminum material. 
     
     
         9 . The capacitor of  claim 1 , wherein the capacitive element comprises electrode tabs, and the lid comprises leads, and wherein the leads are connected to the electrode tabs. 
     
     
         10 . A method for producing a capacitor, the method comprising:
 forming a canister from a shell and a base at a first end of the shell;   creating a groove in the shell;   placing a lid in the shell against the groove, wherein the lid comprises an elastomer on a first side of the lid and a support surface on a second side of the lid, wherein the support surface is adjacent to the groove; and   rolling an edge of the second end of the shell to create a rolled portion;   sealing the canister by rolling the rolled portion against the elastomer.   
     
     
         11 . The method of  claim 10 , further comprising rolling the edge away from a longitudinal axis of the shell. 
     
     
         12 . The method of  claim 10 , further comprising rolling the edge towards a longitudinal axis of the shell. 
     
     
         13 . The method of  claim 10 , wherein the lid is fixed between the groove and the rolled portion. 
     
     
         14 . The method of  claim 10 , further comprising attaching electrode leads to the lid. 
     
     
         15 . The method of  claim 10 , wherein the capacitor is rated for between 125 volts and 600 volts. 
     
     
         16 . The method of  claim 10 , wherein the capacitor comprises a capacitance of between 0.5 millifarads and 5 millifarads. 
     
     
         17 . The method of  claim 10 , wherein the canister comprises an aluminum material. 
     
     
         18 . The method of  claim 10 , wherein the capacitor comprises an electrolyte disposed in the canister. 
     
     
         19 . The method of  claim 10 , wherein the capacitor comprises a capacitive element. 
     
     
         20 . The method of  claim 10 , wherein the capacitive element comprises electrode tabs, and the lid comprises leads, and wherein the leads are connected to the electrode tabs.