Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Sanyo Electric Co., Ltd.

Other

Sony Corporation

Shinji Kasamatsu

Mikinari Shimada

Hajime Nishino

Masato Fujikawa

Hideharu Takezawa

Yoshiaki Nitta

Kazuhiro Okamura

Harunari Shimamura

Shuji Tsutsumi

Na Wang

Masaya Ugaji

Masaki Hasegawa

Tomohiko Yokoyama

Yoshio Kato

Taiki Satow

Tetsuya Hayashi

Masatoshi Takahashi

Hiroshi Yoshizawa

Takuya Ishii

Yusuke Fukumoto

Yukihiro Okada

Yasuhiko Bito

Hizuru Koshina

Hiroyuki Handa

Masayuki Nagamine

Tsumoru Ohata

Kohei Suzuki

Yoshiyuki Muraoka

Kenichi Suzuki

Shigeo Ikuta

Shoichiro Watanabe

Naoyuki Wada

Nobuhiro Hirano

Junji Nakajima

Masato Iwanaga

Miyuki Nakai

Yoshiyuki Ozaki

Yasunori Nishida

Akiko Fujino

Junichi Yamaura

Tooru Fuse

Yasufumi Nakajima

Hiroki Muraoka

Miho Kayama

Yasuo Fukase

Takuji Hirano

Keiko Nishioka

Hideharu Satou

A non-aqueous electrolyte secondary battery having a long cycle life and generates a small amount of gas during, for example, storage in a charged state. A negative electrode in a non-aqueous electrolyte secondary battery according to an exemplary embodiment includes a negative electrode current collector and a negative electrode mixture layer formed on the negative electrode current collector. The negative electrode mixture layer contains a water-soluble polymer and a negative electrode active material containing a silicon-based active material. The water-soluble polymer contains 0.30 mol/100 g or more and 0.40 mol/100 g or less of an acrylic acid monomer unit and 10mol/100 g or more and 10mol/100 g or less of a tetrafunctional (meth)acrylate monomer unit. An aqueous solution containing 1% by mass of the polymer in terms of solid content has a viscosity of 0.05 Pa&#xb7;s or higher and 0.70 Pa&#xb7;s or lower.

Non-aqueous electrolyte secondary battery

Gas evolution during the high-temperature storage of a non-aqueous electrolyte secondary battery is suppressed to improve the high-temperature storage characteristics of the non-aqueous electrolyte secondary battery. A negative electrode for a non-aqueous electrolyte secondary battery contains silicon-containing particles and graphite particles. A covering layer is disposed on each of the graphite particles. The covering layer contains a first covering material and a second covering material, the first covering material containing particles that can be made to swell with a non-aqueous electrolytic solution, the second covering material containing a water-soluble polymer material. The first covering material is disposed on a surface of each of the graphite particles. The mass ratio of the second covering material to the first covering material is higher than 1.

Negative electrode for non-aqueous electrolyte secondary battery

A non-aqueous electrolyte secondary battery including a silicon material as a negative electrode active material has good discharge rate characteristics. A negative electrode according to an exemplary embodiment includes a negative-electrode current collector and a negative-electrode mixture layer formed on the current collector. The negative-electrode mixture layer contains graphite and a silicon material. A first region that extends from the surface of the mixture layer remote from the negative-electrode current collector in the thickness direction of the negative-electrode mixture layer and has a thickness equal to 40% of the thickness of the mixture layer contains a larger amount of the silicon material than a second region that extends from the surface of the mixture layer adjacent to the negative-electrode current collector and has a thickness equal to 40% of the thickness of the mixture layer. The first region has a lower density than the second region.

Negative electrode for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery

Provided is a negative electrode for lithium ion secondary batteries, which can enhance the penetration of non-aqueous electrolyte, and can improve the input-output characteristics. The negative electrode includes a negative electrode core material sheet, and a negative electrode material mixture layer supported thereon. The negative electrode material mixture layer includes negative electrode active material particles, and a binder. The negative electrode material mixture layer has a plurality of pores interspersed on the surface and in the interior of the negative electrode material mixture layer. The pores have an average maximum diameter R of 45 to 125 &#x3bc;m. The pores have a number density of 8 to 17 pores per 1 cmof the surface of the negative electrode material mixture layer or per 1 cmof a cross section in the plane direction of the negative electrode material mixture layer.

Negative electrode for lithium ion secondary batteries and method for producing the negative electrode, and lithium ion secondary battery

In the non-aqueous electrolyte secondary battery of the present invention, the separator includes a heat-resistant resin having chlorine atoms as an end group and the positive electrode active material includes a lithium-containing complex oxide containing aluminum atoms in its composition. Even if the chlorine atoms are liberated into the non-aqueous electrolyte, aluminum contained in the positive electrode active material is selectively leached into the non-aqueous electrolyte, thereby suppressing the leaching of other component elements. Consequently, there can be obtained a non-aqueous electrolyte secondary battery excellent in safety and high temperature storage characteristics.

Nonaqueous electrolyte secondary battery with high temperature and storage characteristics

The non-aqueous electrolyte secondary battery of the present invention is provided with an electrode plate group and a non-aqueous electrolyte, the electrode plate group including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, a positive electrode lead connected to the positive electrode, and a negative electrode lead connected to the negative electrode. The energy density of the electrode plate group is 750 Wh/L or higher by volume, and the cross-sectional area of at least one of the positive electrode lead and the negative electrode lead is 5.5&#xd7;10to 1.2&#xd7;10cm.

A non-aqueous electrolyte secondary battery including: a positive electrode having a positive electrode material mixture containing a composite lithium oxide; a negative electrode; a polyolefin separator; a non-aqueous electrolyte; and a heat-resistant insulating layer interposed between the positive and negative electrodes. The positive electrode material mixture has an estimated heat generation rate at 200&#xb0; C. of not greater than 50 W/kg. The positive electrode and the negative electrode are wound together with the separator and the heat-resistant insulating layer interposed therebetween.

An object of the present invention is to provide an electrode for a lithium ion secondary battery that can ensure a high level of safety even when exposed to severe conditions such as a nail penetration test or crush test, and exhibit excellent output characteristics. The present invention relates to an electrode for a lithium ion secondary battery having a material mixture containing active material particles capable of reversibly absorbing and desorbing lithium, and a current collector that carries the material mixture, wherein a surface of the current collector has recessed portions, and an area occupied by the recessed portions accounts for not less than 30% of an a material mixture carrying area of the current collector. The present invention further relates to an electrode for a lithium ion secondary battery wherein, in a cut surface obtained by simultaneously cutting a material mixture and a current collector vertically to an electrode plane, the maximum depth of recessed portions is not less than 1 &#x3bc;m, or a difference between an average thickness of a current collector and a maximum thickness of the current collector is not less than 0.35 &#x3bc;m.

Electrode for lithium ion secondary battery

A negative electrode for a lithium ion secondary battery includes a negative electrode core member and a negative electrode mixture layer adhering to the negative electrode core member. The negative electrode mixture layer includes active material particles, a cellulose ether compound, and rubber particles. The cellulose ether compound has a degree of etherification of 0.25 or more and 0.7 or less and an average degree of polymerization of 20 or more and 1200 or less. The negative electrode mixture layer contains remaining particles including a water-insoluble portion of the cellulose ether compound and having a mean particle size of 1 &#x3bc;m or more and 75 &#x3bc;m or less. The bonding strength between the active material particles is 98 N/cmor more.

Negative electrode for lithium ion secondary battery and lithium ion secondary battery including the same

A lithium ion secondary battery includes a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator interposed between the positive electrode and the negative electrode. The separator includes a polyolefin layer and an oxidation-resistant layer. The oxidation-resistant layer includes an oxidation-resistant polymer. A main chain of the oxidation-resistant polymer does not include a &#x2014;CH&#x2014; group and a &#x2014;CH(CH)&#x2014; group. The oxidation-resistant layer faces the positive electrode.

Lithium ion secondary battery and charge system therefor

The invention provides a method for evaluating the safety of a battery under an internal short-circuit condition. The battery includes: an electrode group including a positive electrode, a negative electrode, and an insulating layer for electrically insulating the electrodes, which are wound or laminated; an electrolyte; a housing for housing the electrode group and the electrolyte; and a current-collecting terminal for electrically connecting the electrode group and the housing. The method of the invention includes: placing a foreign object at a location inside the electrode group of the battery where the positive electrode and the negative electrode face each other; and pressing the location by the pressure applied by a pressing tool to locally crush the insulating layer between the positive and negative electrodes, thereby causing an internal short-circuit. The contact area of the electrode group and the pressing tool during the pressing is larger than the area of a rectangle circumscribed about the foreign object. A short-circuit test is conducted at a given location inside the battery to comprehensively evaluate the safety of the battery under an internal short-circuit condition.

Method for evaluating battery safety under internal short-circuit condition, battery and battery pack whose safety is identified by internal short-circuit safety evaluation method, and method for producing the same

A separator for use in a non-aqueous electrolyte secondary battery including a first porous layer (layer A) having a shutdown function which becomes substantially a non-porous layer at a high temperature, and a second porous layer (layer B) including an aramid resin and an inorganic material, wherein a ratio (T/T) of a thickness (T) of the layer A relative to a thickness (T) of the layer B is 2.5 or more and 13 or less.

Separator for use in non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery

In a lithium ion secondary battery including a flat-plate electrode assembly which is configured by stacking the positive electrode, the separator, and the negative electrode in the thickness direction thereof, each of the positive electrode and the negative electrode includes a current collector and an active material layer. Each of the current collector includes a substantially rectangular current collector body, a heat radiating portion, and a lead portion, and the heat radiating portions are projected toward the outside of the electrode assembly so as not to overlap with each other in the thickness direction of the electrode assembly. In this way, heat caused inside the lithium ion secondary battery can be diffused efficiently to the outside, and safety of the lithium ion secondary battery can be further increased, without complicating the battery structure and decreasing mechanical strength of the battery.

Lithium ion secondary battery

In a non-aqueous electrolyte secondary battery, a separator in which its dynamic hardness DH obtained when the load to an indenter reaches 12 kgf/cmis 1000 or more is used. This separator includes at least one porous layer X including a polyolefin, and at least one porous layer Y including a heat resistant resin. The porosity of the porous layer X is 35% or more and 65% or less. In a pore size distribution of the porous layer X measured with a mercury porosimeter, a ratio of pores having a pore size of 0.02 &#x3bc;m or more and 0.2 &#x3bc;m or less is 40 vol % or more relative to a total pore volume. The thermal deformation temperature of the heat resistant resin is 160&#xb0; C. or more.

Separator and non-aqueous electrolyte secondary battery

A non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, a non-aqueous electrolyte, and an insulating layer formed on a surface of the positive electrode. The positive electrode includes a lithium nickel composite oxide having a layer structure, and the lithium nickel composite oxide is represented by the general formula: LiNiMOwhere M is at least one selected from the group consisting of Na, Mg, Sc, Y, Mn, Fe, Co, Cu, Zn, Al, Cr, Pb, Sb, and B, 0&#x3c;x&#x2266;1.2, and 0.5&#x3c;y&#x2266;1.0. The non-aqueous electrolyte includes a solute and a non-aqueous solvent dissolving the solute, and the non-aqueous solvent contains 40% by weight or more of a cyclic carbonic acid ester. The insulating layer includes an insulating polymeric material.

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Osaka, Japan

Shinji Kasamatsu