Electrode foil and capacitor using same

An electrode foil comprising:

• a substrate;
• and
• a coarse film layer having a void therein and formed on the substrate,
• wherein the coarse film layer includes at least a first coarse film layer formed on the substrate, the first coarse film layer is composed of arrayed first columnar bodies,
• each of the first columnar bodies is composed of metallic microparticles stacked on a surface of the substrate and extends in a curve from the surface of the substrate, and
• the substrate and the coarse film layer mainly contain aluminum, and an alloy containing at least aluminum and zinc is formed in a region immediately below a bonded interface between the substrate and one of the metallic microparticles as an alloy portion, or the alloy is formed inside the surface, of the substrate, on which the coarse film layer is formed, as an alloy layer.

A capacitor comprising:

• a capacitor element having:
• a positive electrode foil on which a dielectric film is formed;
• a solid electrolytic layer formed on the dielectric film of the positive electrode foil;
• and
• a negative electrode layer formed on the solid electrolytic layer;
• and
• an outer package covering the capacitor element,
• wherein the positive electrode foil includes a substrate and a coarse film layer having a void therein and a thickness of at least 20 μm, and formed on the substrate,
• the coarse film layer includes at least a first coarse film layer formed on the substrate, the first coarse film layer is composed of arrayed first columnar bodies, each of the first columnar bodies is composed of metallic microparticles stacked on a surface of the substrate in such a manner that an original shape of each of the metallic microparticles is maintained, and is branched and extends from the surface of the substrate so as to be curved at a portion between a base and a leading end of each of the first columnar bodies, the first columnar bodies are curved in an identical direction and substantially parallel to each other, and the dielectric film is formed on the coarse film layer.

A capacitor comprising:

• a capacitor element having:
• a positive electrode foil on which a dielectric film is formed;
• a solid electrolytic layer formed on the dielectric film of the positive electrode foil;
• and
• a negative electrode layer formed on the solid electrolytic layer;
• and
• an outer package covering the capacitor element,
• wherein the positive electrode foil includes a substrate and a coarse film layer having a void therein and formed on the substrate,
• the coarse film layer includes at least a first coarse film layer formed on the substrate, the first coarse film layer is composed of arrayed first columnar bodies, each of the first columnar bodies is composed of metallic microparticles stacked on a surface of the substrate and extends in a curve from the surface of the substrate, and the dielectric film is formed on the coarse film layer, and
• the substrate and the coarse film layer mainly contain aluminum, and an alloy portion containing at least aluminum and zinc is formed in a region immediately below a bonded interface between the substrate and one of the metallic microparticles.

A capacitor comprising:

• a capacitor element having:
• a positive electrode foil on which a dielectric film is formed;
• a negative electrode foil;
• and
• a separator interposed between the positive electrode foil and the negative electrode foil;
• a negative electrode material with which the capacitor element is impregnated;
• a case accommodating the capacitor element therein;
• and
• a sealing unit sealing the case,
• wherein at least one of the positive electrode foil and the negative electrode foil includes a substrate and a coarse film layer having a void therein and a thickness of at least 20 μm, and formed on the substrate,
• the coarse film layer includes at least a first coarse film layer formed on the substrate, the first coarse film layer is composed of arrayed first columnar bodies, each of the first columnar bodies is composed of metallic microparticles stacked on a surface of the substrate in such a manner that an original shape of each of the metallic microparticles is maintained, and is branched and extends from the surface of the substrate so as to be curved at a portion between a base and a leading end of each of the first columnar bodies, the first columnar bodies are curved in an identical direction and substantially parallel to each other, and the dielectric film is formed on the coarse film layer in a case that the positive electrode foil includes the coarse film layer.

A capacitor comprising:

• a capacitor element having:
• a positive electrode foil on which a dielectric film is formed;
• a negative electrode foil;
• and
• a separator interposed between the positive electrode foil and the negative electrode foil;
• a negative electrode material with which the capacitor element is impregnated;
• a case accommodating the capacitor element therein;
• and
• a sealing unit sealing the case,
• wherein least one of the positive electrode foil and the negative electrode foil includes a substrate and a coarse film layer having a void therein and formed on the substrate,
• the coarse film layer includes at least a first coarse film layer formed on the substrate, the first coarse film layer is composed of arrayed first columnar bodies, each of the first columnar bodies is composed of metallic microparticles stacked on a surface of the substrate and extends in a curve from the surface of the substrate, and the dielectric film is formed on the coarse film layer in a case that the positive electrode foil includes the coarse film layer, and
• the substrate and the coarse film layer mainly contain aluminum, and an alloy containing at least aluminum and zinc is formed in a region immediately below a bonded interface between the substrate and one of the metallic microparticles as an alloy portion, or the alloy is formed inside the surface, on which the coarse film layer is formed, as an alloy layer.