Fuji Jukogyo Kabushiki Kaisha

Mitsuru Nagai

Nobuo Ando

Shinichi Tasaki

Kohei Matsui

Yukinori Hato

Takashi Utsunomiya

Kunio Nakazato

Hiromoto Taguchi

Atsuro Shirakami

Ken Baba

Yutaka Sato

Kenji Kojima

Osamu Hatozaki

Yukinori Hatou

Risa Takahata

A lithium-ion capacitor excellent in durability, which has high energy density and high capacity retention ratio when the capacitor is charged and discharged at a high load, is disclosed. The lithium-ion capacitor includes a positive electrode, a negative electrode and an aprotic organic solvent of a lithium salt as an electrolyte solution. In the lithium-ion capacitor, a positive electrode active material allows lithium ions and/or anions to be doped thereinto and de-doped therefrom, and a negative electrode active material allows lithium ions to be doped thereinto and de-doped therefrom. At least one of the negative electrode and the positive electrode is pre-doped with lithium ions so that after the positive electrode and the negative electrode are shortcircuited, a potential of the positive electrode is 2 V (relative to Li/Li+) or lower. A thickness of a positive electrode layer of the positive electrode is within a range from 18 to 108 &#x3bc;m.

Lithium-ion capacitor

A lithium ion capacitor includes, as a lithium ion supply source, a lithium metal foil for batteries or capacitors. A current collectorand a separatorformed of a paper or resin nonwoven fabric are preliminarily pressure-bonded and integrated to opposite surfaces of a lithium metal foilfor batteries or capacitors.

Lithium metal foil for battery or capacitor

A resist layer is formed over one surface of a current-collector material, while a resist layer having a predetermined pattern is formed on the other surface of the current-collector material. Through-holes are formed on the current-collector material through an etching process. An electrode slurry is applied onto the current-collector material formed with the through-holes without removing the resist layers. Specifically, since the through-holes are closed by the resist layer, the electrode slurry does not pass through the through-holes to leak out. Therefore, the current-collector material can be conveyed in the horizontal direction, whereby the productivity of an electrode can be enhanced. The resist layers are made of PVdF, and the resist layers are removed in a heating and drying step in which the PVdF is dissolved.

Manufacturing process of electrode

An electric storage devicehas an electrode laminate unitincluding positive electrodes, negative electrodesand a lithium electrodeprovided at the outermost part of the electrode laminate unit. The lithium electrodehas a lithium-electrode current collectorwelded to a negative-electrode current collectorand a lithium unitsandwiched between the lithium-electrode current collectorand the negative electrode. The lithium unitis composed of a lithium holding platethat is in contact with the lithium-electrode current collector, and a lithium ion sourcethat is provided to the lithium holding plate. The lithium ion sourceis not mounted on the lithium-electrode current collector, but only the lithium-electrode current collectoris laminated and welded, whereby the damage of the lithium ion sourceis prevented, and the manufacturing operation is simplified.

Electric storage device

An electrode laminate unit of an electric storage device includes positive electrodes, negative electrodes and a lithium electrode connected to the negative electrode. When an electrolyte solution is injected into the electric storage device, lithium ions are emitted from the lithium electrode to the negative electrode. A positive and a negative electrode current collector have through-holes that guide the lithium ions in the laminating direction. The aperture ratio of the through-holes at the edge parts where the electrolyte solution is easy to be permeated is set to be smaller than the aperture ratio at central parts in order to suppress the permeation. Thus, the distribution of the electrolyte solution is made uniform, whereby the doping amount is made uniform.

In a current collector laminating step, a current-collector laminate unitcomposed of current-collector materialsandand a film materialis formed. Resist layershaving a predetermined pattern are formed on both surfaces of the current-collector laminate unit. An etching process is performed with the resist layersused as a mask, whereby through-holesandare formed on the respective current-collector materialsand. The resist layersare removed from the current-collector laminate unit. Since the etching process is performed on the plural current-collector materialsand, productivity of an electrode can be enhanced. During the application of the slurry, the film materialprevents the leakage of the electrode slurry. Therefore, the current-collector laminate unitcan be conveyed in the horizontal direction, whereby the productivity of the electrode can be enhanced.

Manufacturing method of electrode, electric storage device, and intermediate laminate member

An electric storage devicehas a positive electrode, a negative electrodeand a separatorprovided between the positive electrodeand the negative electrode. The negative electrode surfaceis formed to be larger than the positive electrode surfacein such a manner that a positive electrode outer edgeand a negative electrode outer edgeare apart from each other by 2 mm or more. By this configuration, an ion restricting sectionis formed at the outer peripheral portion of the separator. Accordingly, the movement of the lithium ions toward the negative electrode end surfacecan be restricted, when the device is charged with a large current, whereby the deposition of metal lithium on the negative electrode end surfacecan be prevented.

A lithium ion capacitor having high energy density, high output density, high capacity and high safety includes a positive electrode made of a material capable of being reversibly doped with lithium ions and/or anions, a negative electrode made of a material capable of being reversively doped with lithium ions, and an aprotic organic solution of a lithium salt as an electrolytic solution. Wherein, the positive electrode and the negative electrode are laminated or wound with a separator interposed between them, the area of the positive electrode is smaller than the area of the negative electrode. The face of the positive electrode is substantially covered by the face of the negative electrode when they are laminated or wound.

Lithium ion capacitor

A lithium ion capacitor including a positive electrode, a negative electrode, and an aprotic organic solvent solution of a lithium salt as an electrolytic solution. The positive electrode active material is capable of reversibly supporting lithium ions and/or anions, the negative electrode active material is capable of reversibly supporting lithium ions and anions, and the potentials of the positive electrode and the negative electrode are at most 2.0 V after the positive electrode and the negative electrode are short-circuited. The positive electrode and the negative electrode are alternately laminated with a separator interposed therebetween to constitute an electrode unit, the cell is constituted by at least two such electrode units, lithium metal is disposed between the electrode units, and lithium ions are preliminarily supported by the negative electrode and/or the positive electrode by electrochemical contact of the lithium metal with the negative electrode and/or the positive electrode.

It is to provide a lithium ion capacitor having a high energy density, a high output density, a large capacity and high safety. A lithium ion capacitor comprising a positive electrode, a negative electrode and an aprotic organic solvent solution of a lithium salt as an electrolytic solution, wherein a positive electrode active material is a material capable of reversibly supporting lithium ions and anions, a negative electrode active material is a material capable of reversibly supporting lithium ions, and the potentials of the positive electrode and the negative electrode are at most 2.0 V after the positive electrode and the negative electrode are short-circuited, characterized in that the positive electrode and the negative electrode are respectively made by forming electrode layers by the positive electrode active material and the negative electrode active material on both sides of a positive electrode current collector and a negative electrode current collector each having pores penetrating from the front surface to the back surface, the capacitor has such a cell structure that the positive electrode and the negative electrode are wound or laminated, and the outermost portion of the wound or laminated electrodes is the negative electrode.

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Tokyo, Japan

Mitsuru Nagai