US 12,283,438 B2
Electrolytic capacitor
Katsutomo Aritomi, Nagaokakyo (JP); and Wataru Onishi, Nagaokakyo (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Nagaokakyo (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Mar. 30, 2022, as Appl. No. 17/657,152.
Application 17/657,152 is a continuation of application No. PCT/JP2020/037410, filed on Oct. 1, 2020.
Claims priority of application No. 2019-183946 (JP), filed on Oct. 4, 2019.
Prior Publication US 2022/0223350 A1, Jul. 14, 2022
Prior Publication US 2023/0215664 A9, Jul. 6, 2023
Int. Cl. H01G 9/15 (2006.01); H01G 9/012 (2006.01); H01G 9/042 (2006.01); H01G 9/048 (2006.01); H01G 9/08 (2006.01); H01G 9/10 (2006.01)
CPC H01G 9/15 (2013.01) [H01G 9/012 (2013.01); H01G 9/0425 (2013.01); H01G 9/048 (2013.01); H01G 9/08 (2013.01); H01G 9/10 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An electrolytic capacitor comprising:
a cuboid resin molded body having a first end surface and a second end surface opposite to each other, the cuboid resin molded body including a stack that includes a capacitor element with an anode having a dielectric layer on a surface thereof and a cathode opposite to the anode, and a sealing resin that seals the stack, the anode being exposed on the first end surface and the cathode being exposed at the second end surface;
a first external electrode on the first end surface of the resin molded body and electrically connected to the anode exposed on the first end surface; and
a second external electrode on the second end surface of the resin molded body and electrically connected to the cathode exposed on the second end surface,
wherein each of the first external electrode or the second external electrode has a multilayer structure including:
an inner plating layer on a surface of the anode exposed on the first end surface or on a surface of the cathode exposed on the second end surface; and
a resin electrode layer on a surface of the inner plating layer and containing a resin component and at least one metal selected from the group consisting of Ni or a Ni alloy,
the inner plating layer is a Ni plating layer having a thickness of 3 μm to 10 μm, the anode of the capacitor element includes a valve-action metal foil,
the inner plating layer of the first external electrode is only on and around an end of the valve-action metal foil exposed on the first end surface so that a part of the resin electrode layer of the first external electrode is in contact with the first end surface,
the resin electrode layer of the first external electrode is electrically connected to the inner plating layer of the first external electrode,
the cathode of the capacitor element includes a solid electrolyte layer on the dielectric layer, a conductive layer on the solid electrolyte layer, and a cathode lead-out layer on the conductive layer,
the cathode lead-out layer includes a metal foil or a printed electrode layer,
the inner plating layer of the second external electrode is only on and around an end of the metal foil or the printed electrode layer exposed on the second end surface so that a part of the resin electrode layer of the second external electrode is in contact with the second end surface,
the resin electrode layer of the second external electrode is electrically connected to the inner plating layer of the second external electrode,
a total number of layers defining each of the first external electrode and the second external electrode is four or less, and
a variation in thickness of the first external electrode measured from the first end surface of the resin molded body and a variation in thickness of the second external electrode measured from the second end surface of the resin molded body are each 20 μm or less.