Solid electrolytic capacitor
View Patent ↗The invention provides a solid electrolytic capacitor of a configuration having a metal plated layer in a cathode part in order to prevent a decrease in the conductivity by oxidation of a conductive polymer and to realize a high reliability. Also there is provided a configuration in which a cathode part of the solid electrolytic capacitor includes a first metal plated layer and a solderable second metal layer.
1. A solid electrolytic capacitor comprising:
an anode part including a lead wire which comprises at least one end of a metal piece and which has an oxide film formed on a part thereof;
a solid electrolyte comprising a conductive polymer layer formed on said oxide film;
a cathode part comprising:
a conductive material layer formed on said conductive polymer layer;
a first metal plated layer; and
a solderable second metal layer on said first metal plated layer.
2. A solid electrolytic capacitor according to claim 1 , wherein said first metal plated layer comprises at least one of a copper plated layer, a nickel plated layer, a gold plated layer, and a silver plated layer.
3. A solid electrolytic capacitor according to claim 1 , wherein said second metal layer comprises at least one of a solder layer, a tin layer and a solderable silver paste layer.
4. A surface mounting solid electrolytic capacitor comprising:
an anode part including a lead wire which comprises at least one end of a metal piece and which has an oxide film formed on a part thereof;
a solid electrolyte comprising a conductive polymer layer formed on said oxide film;
a cathode part comprising:
a conductive material layer formed on said conductive polymer layer;
a first metal elated layer; and
a cathode terminal connected to said cathode part, said cathode terminal comprising:
a solderable third metal plated layer on a mounting surface of said cathode terminal; and
a fourth metal plated layer on a surface of said cathode terminal to be adjoined to said cathode part,
wherein said fourth metal plated layer has a higher melting temperature than said third metal plated layer and is chemically stable.
5. A solid electrolytic capacitor according to claim 4 , wherein said third metal plated layer comprises at least one of a solder plated layer and a tin plated layer.
6. A solid electrolytic capacitor according to claim 4 , wherein said fourth metal plated layer comprises at least one of a gold plated layer and a silver plated layer.
7. A solid electrolytic capacitor according to claim 1 , wherein said conductive material layer comprises a graphite layer, and a silver paste is formed on said graphite layer.
8. A solid electrolytic capacitor according to claim 1 , wherein said metal piece comprises aluminum, and said oxide film comprises aluminum oxide.
9. A solid electrolytic capacitor according to claim 1 , further comprising an insulating resin which is provided around a boundary between a central part and the anode part of said metal piece, and which divides said metal piece into a first area for developing a capacitance and a second area which is adapted to be connected to an external anode terminal.
10. A solid electrolyte capacitor according to claim 1 , wherein said at least one end of the metal piece comprises both ends of said metal piece.