Tdk Corporation

Masahiro Saegusa

Kiyonori Hinoki

Kazutoshi Emoto

Katsuo Naoi

Keitaro Otsuki

Mitsuo Kougo

Kenji Nishizawa

Tetsu Sato

Haruka Nishimura

Masayoshi Hirano

Hirokazu Ohnuma

Bungo Sakurai

A negative electrode includes a current collector and a negative electrode active material layer that is provided on the current collector and includes a negative electrode active material. The negative electrode active material includes a carbon material, and a surface of the negative electrode active material layer has a spectral reflectance Ra in a range of 7.0&#x2264;Ra&#x2264;10.8% at a wavelength of 550 nm.

Negative electrode active material layer with controlled reflectance and lithium ion secondary battery

A positive electrode includes a positive electrode current collector, and a positive electrode active material layer that is provided on the positive electrode current collector and that includes a positive electrode active material, a conductive auxiliary agent, and a binder. A surface of the positive electrode active material layer has a reflectance Rc in a range of 2.0&#x2264;Rc&#x2264;12.0% at a wavelength of 550 nm. A lithium ion secondary battery includes: the positive electrode; a negative electrode including a negative electrode current collector and a negative electrode active material layer that is provided on the negative electrode current collector and that includes a negative electrode active material; a separator; and a nonaqueous electrolyte solution. A surface of the negative electrode active material layer has a reflectance Ra in a range of 7.5&#x2264;Ra&#x2264;16.0% at a wavelength of 550 nm.

Positive electrode and lithium ion secondary battery

A negative electrode includes a negative electrode current collector and a negative electrode active material layer that is provided on the negative electrode current collector and includes a negative electrode active material. The negative electrode active material includes a carbon material, and a surface of the negative electrode active material layer has a reflectance Ra in a range of 7.0&#x2264;Ra&#x2264;14.8% at a wavelength of 550 nm. A lithium ion secondary battery includes the negative electrode, a positive electrode, a separator, and a nonaqueous electrolyte solution. The nonaqueous electrolyte solution includes a nonaqueous solvent and an electrolyte, the nonaqueous solvent contains ethylene carbonate, and the ethylene carbonate is contained in a range of 10 to 30 vol. % in the entire nonaqueous solvent.

A separator according to the embodiment includes a porous base material having a thermoplastic resin. The porous base material has a heat-resistant porous layer on at least one surface thereof. The heat-resistant porous layer contains inorganic particles, a resin, and sulfur. A lithium ion secondary battery according to the embodiment, includes: the separator interposed between a positive electrode and a negative electrode; and an electrolyte solution. The heat-resistant porous layer is disposed between the positive electrode and the porous base material. Sulfur is distributed unevenly in the heat-resistant porous layer so as to exist in larger amount near a surface thereof opposite to the porous base material.

Separator and lithium ion secondary battery including the same

A fiber-containing polymer film contains a host polymer and fibrous substances. The fiber-containing polymer film has an orientation area where the fibrous substances are oriented in a direction substantially parallel to a main surface of the fiber-containing polymer film and in substantially the same direction.

Fiber-containing polymer film and method of manufacturing same, and electrochemical device and method of manufacturing same

An electrode manufacturing method which can lower the impedance of electrochemical devices is provided. The electrode manufacturing method comprises the steps of applying a coating material containing an active material particle, a binder, and a good solvent for the binder to a current collector, so as to form a coating film made of the coating material; removing the good solvent from the coating film; applying a poor solvent for the binder to the coating film having removed the good solvent; and pressing the coating film coated with the poor solvent.

Electrode manufacturing method

A lithium ion secondary battery containing a pair of electrodes facing each other, and a separator interposed between the electrodes, wherein at least one of the electrodes has a protecting layer, an active-material containing layer, and a collector sequentially from the separator. The protecting layer contains a silicone resin particle having at least one structural unit represented by RSiOand RSiO, where R represents an alkyl group having 1 to 6 carbon atoms or a phenyl group.

Electrode comprising protective layer for lithium ion secondary battery and lithium ion secondary battery

An electrode for a lithium ion secondary battery having a collector, an active-material layer formed on the collector and a protecting layer formed on the active-material layer, in which the protecting layer contains an organic particle formed of poly(methyl methacrylate) having a crosslinked structure, and the organic particle has an average particle size (D50) of 0.5 to 4.0 &#x3bc;m.

A liquid application apparatus includes a guide roll for guiding a sheet for application, and a slit die for applying a liquid to a surface of the sheet for application from an opening. The slit die has an upper layer flow path and a lower layer flow path spaced in the rotational direction of the guide roll and joining at the opening. In a cross section perpendicular to the axis of the guide roll, an angle &#x3b1; formed by the center line of the upper layer flow path and the center line of the lower layer flow path is 0.5 to 25&#xb0;, an angle &#x3b2; formed by a line connecting the intersection point of the center line of the upper layer flow path and the center line of the lower layer flow path with the axis of the guide roll and by the center line of the upper layer flow path is 0 to 70&#xb0; as measured from this connecting line toward the center line of the upper layer flow path in the direction opposite to the rotational direction of the guide roll, and the distance &#x3b3; between a point where the two flow paths and join and the opening is 0.05 to 2.8 mm.

Liquid application apparatus and application method

An electrode producing method by an electrode producing apparatus has an inclining step of pressing a surface of a current collector sheet with projections extending outwardly from the surface, which is conveyed in a definite direction, to incline the projections in a direction opposite to the definite direction of the current collector sheet; and an applying step of applying a coating solution onto the current collector sheet, the projections of which have been inclined in the inclining step and which is conveyed in the definite direction, by a slit die. After the surface of the current collector sheet is pressed to incline the projections on the sheet surface in the opposite direction to the conveyance direction, the coating solution is applied onto the surface. Therefore, the coating solution can be uniformly applied onto the current collector sheet.

Electrode producing method and electrode producing apparatus

An electrode having a current collector with a plurality of through holes, and active material layers provided on both sides of the current collector. The current collector has projections extending on the top side or on the back side of the current collector from edges of the through holes, and an angle between each of the projections and a surface direction of the current collector is in the range of 30 to 80&#xb0;.

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Tokyo, Japan

Masahiro Saegusa