Electrolytic capacitor

Abstract

An electrolytic capacitor employs a capacitor element wherein an anode foil having an anode internal terminal and a cathode foil having a cathode internal terminal are wound or laminated through a separator. The end of the anode foil faces the cathode foil through the separator and the surface area of the cathode internal terminal is provided with an enlargement treatment, whereby the small area portion of the cathode foil that faces with the anode foil is eliminated, improving the charge/discharge characteristics. Furthermore, in the electrolytic capacitor provided with the capacitor element wherein the anode foil having the anode internal terminal and the cathode foil having the cathode internal terminal are wound or laminated through the separator, the capacitor element being impregnated with an electrolyte, the cathode internal terminal includes an aluminum material, the surface of the cathode internal terminal is etched and iron concentration in the etching layer <300 ppm.

1 . An electrolytic capacitor provided with a capacitor element in which an anode foil having an anode internal terminal and a cathode foil having a cathode internal terminal are wound or laminated through a separator, the capacitor element being impregnated with an electrolyte,
 wherein the surface of said cathode internal terminal is comprised of a lysis-treated aluminum, and wherein the iron concentration in the lysis-treated layer formed through said lysis treatment is less than 300 ppm.   
   
   
       2 . The electrolytic capacitor according to  claim 1 , wherein said lysis treatment is an etching treatment. 
   
   
       3 . An electrolytic capacitor provided with a capacitor element in which an anode foil having an anode internal terminal and a cathode foil having a cathode internal terminal are wound or laminated through a separator,
 wherein an end of the anode foil faces with the cathode foil through a separator, and wherein the surface area of the cathode internal terminal is provided with an enlargement treatment.   
   
   
       4 . The electrolytic capacitor according to  claim 3 , provided with a capacitor element in which an anode foil having an anode internal terminal and a cathode foil having a cathode internal terminal are wound through a separator,
 wherein the cathode foil firstly starts being wound and then the anode foil is wound together so that the end of the cathode foil  3  comes at the winding end portion.   
   
   
       5 . The electrolytic capacitor according to  claim 3 , wherein the entire surface of the anode foil faces with the cathode foil through the separator. 
   
   
       6 . The electrolytic capacitor according to  claim 1 , wherein the degree of purity of aluminum of said cathode internal terminal is 99.9% or greater. 
   
   
       7 . The electrolytic capacitor according to  claim 1 , wherein said cathode internal terminal has a chemical formed coating thereon. 
   
   
       8 . The electrolytic capacitor according to  claim 1 , wherein an etching treatment is provided to said cathode foil, and wherein the etching magnification of the cathode internal terminal is greater than that of the cathode foil by at least 5%. 
   
   
       9 . The electrolytic capacitor according to  claim 1 , wherein the pH range of said electrolyte is from 5 to 7. 
   
   
       10 . The electrolytic capacitor according to  claim 1 , wherein a low-density plane of said separator is arranged to face with said cathode internal terminal. 
   
   
       11 . The electrolytic capacitor according to  claim 1 , wherein said separator comprises kraft, hemp or cotton. 
   
   
       12 . The electrolytic capacitor according to  claim 1 , wherein the capacitor element is impregnated with the electrolyte, and wherein the electrolyte contains amine salt. 
   
   
       13 . The electrolytic capacitor according to  claim 1 , wherein the chemical formed coating of the anode foil is comprised of an evenly crystallized layer formed on the aluminum and a silicon-containing layer formed on the evenly crystallized layer. 
   
   
       14 . The electrolytic capacitor according to  claim 3 , wherein the degree of purity of aluminum of said cathode internal terminal is 99.9% or greater. 
   
   
       15 . The electrolytic capacitor according to  claim 3 , wherein said cathode internal terminal has a chemical formed coating thereon. 
   
   
       16 . The electrolytic capacitor according to  claim 3 , wherein an etching treatment is provided to said cathode foil, and wherein the etching magnification of the cathode internal terminal is greater than that of the cathode foil by at least 5%. 
   
   
       17 . The electrolytic capacitor according to  claim 3 , wherein the pH range of said electrolyte is from 5 to 7. 
   
   
       18 . The electrolytic capacitor according to  claim 3 , wherein a low-density plane of said separator is arranged to face with said cathode internal terminal. 
   
   
       19 . The electrolytic capacitor according to  claim 3 , wherein said separator comprises kraft, hemp or cotton. 
   
   
       20 . The electrolytic capacitor according to  claim 3 , wherein the capacitor element is impregnated with the electrolyte, and wherein the electrolyte contains amine salt.