Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Shigeo Ikuta

Tetsuya Hayashi

Tsumoru Ohata

Kohei Suzuki

Yusuke Fukumoto

Junji Nakajima

Akiko Fujino

Kazufumi Ogawa

Mamoru Soga

Masao Fukunaga

Kouji Nishida

Takashi Takano

Kaoru Inoue

Kiyomi Kato

Shinji Ozaki

Tetsuo Kawakita

Keizaburo Kuramasu

Shin-itsu Takehashi

Mayumi Inoue

Shinji Kasamatsu

Eitaro Nakamura

A lithium ion secondary battery includes a positive electrode capable of absorbing and desorbing lithium ion, a negative electrode capable of absorbing and desorbing lithium ion, a porous film interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, the porous film being adhered to a surface of at least the negative electrode. The porous film includes an inorganic filler and a first binder: The content of the first binder in the porous film is 1.5 to 8 parts by weight per 100 parts by weight of the filler: The first binder includes a first rubber including an acrylonitrile unit: The first rubber is water-insoluble and has a decomposition temperature of 250&#xb0; C. or higher. The negative electrode includes a negative electrode active material capable of absorbing and desorbing lithium ion and a second binder, and the second binder includes a second rubber particle and a water-soluble polymer.

Lithium ion secondary battery

A secondary battery includes: a positive electrode; a negative electrode; a porous electron-insulating layer adhered to a surface of at least one selected from the group consisting of the positive electrode and the negative electrode; and an electrolyte. The porous electron-insulating layer comprises a particulate filler and a resin binder, and the particulate filler comprises an indefinite-shape particle comprising a plurality of primary particles that are joined to one another. A neck is preferably formed between the primary particles. Since the porous electron-insulating layer has high porosity, it is possible to obtain a secondary battery that exhibits excellent low-temperature characteristics, which are particularly important in actual use, and that is capable of discharging at a large current.

Secondary battery

A non-aqueous electrolyte secondary battery including: a positive electrode; a negative electrode; a separator interposed between the positive electrode and the negative electrode; a non-aqueous electrolyte; and a porous insulating film adhered to a surface of at least one selected from the group consisting of the positive electrode and the negative electrode, the porous insulating film including an inorganic oxide filler and a film binder, wherein the ratio R of actual volume to apparent volume of the separator is not less than 0.4 and not greater than 0.7, and wherein the ratio R and a porosity P of the porous insulating film satisfy the relational formula: &#x2212;0.10&#x2266;R&#x2212;P&#x2266;0.30.

Non-aqueous electrolyte secondary battery

A lithium ion secondary battery includes a positive electrode capable of absorbing and desorbing lithium ion, a negative electrode capable of absorbing and desorbing lithium ion, a porous film interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte: the porous film being adhered to a surface of at least one of the positive electrode and the negative electrode; the porous film including a filler and a resin binder; the resin binder content in the porous film being 1.5 to 8 parts by weight per 100 parts by weight of the filler; and the resin binder including an acrylonitrile unit, an acrylate unit, or a methacrylate unit.

A method for producing a lithium ion secondary battery includes the steps of: forming a positive electrode mixture layer on a positive electrode substrate to obtain a positive electrode; forming a negative electrode mixture layer on a negative electrode substrate to obtain a negative electrode; forming an electronically insulating porous film that is bonded to a surface of at least one of the positive electrode and the negative electrode; interposing a separator between the positive electrode and the negative electrode to form an electrode plate assembly; and impregnating the electrode plate assembly with a non-aqueous electrolyte. The step of forming a porous film includes the steps of: preparing a porous film paste that contains a film binder comprising a thermo-cross-linkable resin and a particulate filler; and applying the porous film paste onto a surface of at least one of the positive electrode and the negative electrode and heating the resultant applied film.

Lithium ion secondary battery and method for producing the same

Disclosed is an electrode for lithium ion secondary batteries which includes an active material layer containing active material particles and a porous insulating layer formed on the surface of the active material layer. The porous insulating layer includes an inorganic filler and a resin binder, and the surface of the active material layer has a first region on which the porous insulating layer is formed, and a second region on which the porous insulating layer is not formed. By using such an electrode, a lithium ion secondary battery can have a high capacity, excellent characteristics and improved safety.

Electrode for lithium ion secondary batteries, lithium ion secondary battery using the same, and method for manufacturing the battery

In a secondary battery including a positive electrode, a negative electrode and a porous film bonded to the surface of at least one of the positive electrode and the negative electrode, the porous film includes ceramic particles and a binder, and the ceramic particles include polycrystalline particles obtained by mechanically crushing a fired material comprising a ceramic that is directly synthesized from a ceramic precursor. The porous film has a porosity of 40 to 80%, for example. The porous film can be formed by a method including the steps of: obtaining a fired material comprising a ceramic from a ceramic precursor; obtaining ceramic particles by mechanically crushing the fired material of the ceramic; obtaining a slurry including the ceramic particles and a binder; and applying the slurry onto the surface of an electrode, followed by drying.

Secondary battery and method for producing the same

A lithium ion secondary battery has an electrode group including: a winding core; and a positive electrode and a negative electrode that are wound around the winding core. This electrode group does not have an independent separator between the positive and negative electrodes. A porous film is integrally formed on both sides of at least one of the positive electrode and the negative electrode. The negative electrode and the positive electrode are connected to the winding core by a negative electrode resin film and a positive electrode resin film, respectively. The use of such resin films makes it possible to reduce the breakage of the porous films and prevent a short-circuit between the positive and negative electrodes.

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Kawanabe-gun, Japan

Shigeo Ikuta