Solid electrolytic capacitor containing a deoxidized anode
AssigneeKYOCERA AVX Components Corporation
InventorsMasayuki Wakatsuki, Yusuke Sasaki, Shinpei Etou
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Abstract
A capacitor that comprises a capacitor element is provided. The capacitor element comprises a deoxidized and sintered anode body that is formed from a powder having a specific charge of about 35,000 μF*V/g or more. Further, a dielectric overlies the anode body and a solid electrolyte overlies the dielectric. The capacitor also exhibits a normalized aged leakage current of about 0.1% or less.
Claims20
A solid electrolytic capacitor comprising a capacitor element, the capacitor element comprising a deoxidized and sintered anode body that is formed from a tantalum powder having a specific charge of about 100,000 to about 350,000 μF*V/g, a dielectric which includes tantalum pentoxide and that is formed at a forming voltage of about 35 volts or more that overlies the anode body, and a solid electrolyte that overlies the dielectric, wherein the capacitor exhibits a dielectric strength of about 0.4 V/nm or more and an Aged DCL of about 0.5 μA or less and a normalized aged leakage current of about 0.075% or less as determined according to the following equation:
- Normalized Aged Leakage Current=100×(Aged DCL/CV)
- wherein,
- Aged DCL is the leakage current as measured at a temperature of about 23° C. and at a rated voltage for about 60 seconds after the capacitor is subjected to life testing at a temperature of 85° C. and the rated voltage for 120 hours and then allowed to recover for 60 minutes at a temperature of about 23° C.;
- C is initial capacitance (Farads) as determined at a temperature of about 23° C. and an operating frequency of 120 Hz;
- and
- V is the rated voltage (volts).
A method for forming a solid electrolytic capacitor, the method comprising:
- forming an anode by a process that includes compacting a powder which includes tantalum having a specific charge of about 100,000 to about 350,000 μF*V/g into a porous anode body, subjecting the porous anode body to a deoxidation process to form a deoxidized anode body, sintering the deoxidized anode body;
- anodically oxidizing the deoxidized and sintered anode body at a forming voltage of about 35 volts or more to form a dielectric which includes tantalum pentoxide that overlies the anode body;
- and
- forming a solid electrolyte that overlies the dielectric;
- wherein the capacitor exhibits a dielectric strength of about 0.4 V/nm or more and an Aged DCL of about 0.5 μA or less and a normalized aged leakage current of about 0.075% or less as determined according to the following equation:
- Normalized Aged Leakage Current=100×(Aged DCL/CV)
- wherein,
- Aged DCL is the leakage current as measured at a temperature of about 23° C. and at a rated voltage for about 60 seconds after the capacitor is subjected to life testing at a temperature of 85° C. and the rated voltage for 120 hours and then allowed to recover for 60 minutes at a temperature of about 23° C.;
- C is initial capacitance (Farads) as determined at a temperature of about 23° C. and an operating frequency of 120 Hz;
- and
- V is the rated voltage (volts).
Dependencies are inferred from the claim text.