Sony Corporation

Other

Panasonic Corporation

Sanyo Electric Co., Ltd.

Ishihara Sangoy Kaisha, Ltd.

Masayuki Nagamine

Atsuo Omaru

Akira Yamaguchi

Naoyuki Nakajima

Hiroshi Imoto

Junji Kuyama

Kazuhito Kamei

Noriyuki Negi

Hideya Kaminaka

Hideto Azuma

Shinji Hatake

Koji Moriguchi

Masaru Abe

Mitsuhara Yonemura

Yoshihisa Gonno

Yoshikatsu Yamamoto

Hiroaki Tanizaki

Yoshio Nishi

Hisashi Tsujimoto

Yoshinori Atsumi

Naoyuki Date

Masatoshi Takahashi

Mikinari Shimada

Masayoshi Kanno

Shinichiro Yamada

Naohiro Sonobe

Yosuke Hosoya

Shinji Kasamatsu

Yuzuru Fukushima

Tomoaki Sato

Masato Iwanaga

Jiro Masuko

Kaoru Nakajima

Mitsuharu Yonemura

Hayato Hommura

Hidetoshi Ito

Minoru Ishikawa

Koji Sekai

Yusuke Fujishige

Minoru Hasegawa

Yasuo Fukase

Shunichi Fujishima

Atuo Omaru

Keizou Koga

Tadashi Senoo

Tokuo Suita

Hiromi Koga

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 non-aqueous electrolyte secondary cell which achieves satisfactory low temperature characteristics and high safety against overcharging in combination. The cell includes a lithium-containing cathode, an anode capable of doping and undoping lithium, a non-aqueous electrolyte and a separator. The separator is made up by a plurality of layers of a porous material or materials presenting micro-sized pores. The layers of the porous material or materials is formed of micro-porous separator materials representing different combinations of the porosity, melting point or material/compositions.

Non-aqueous electrolyte secondary cell

An electrolyte solution and a battery which are capable of improving cycle characteristics are provided. An anode includes a simple substance, an alloy or a compound of a metal element or a metalloid element capable of forming an alloy with lithium as an anode active material. A separator is impregnated with an electrolyte solution formed through dissolving an electrolyte salt in a solvent. The electrolyte salt includes a first electrolyte salt including LiB(CO)and a second electrolyte salt including at least one kind selected from the group consisting of LiPF, LiBF, LiN(CFSO), LiN(CFSO), LiClO, LiAsFand LiC(CFSO). In the solvent, 4-fluoroethylene carbonate is included. A coating is formed on the anode by the first electrolyte salt, and high ionic conductivity can be obtained by the second electrolyte salt. Further an oxidation-decomposition reaction of the electrolyte solution which occurs in a cathode can be prevented by 4-fluoroethylene carbonate.

Battery including an electrolyte solution comprising a halogenated carbonate derivative

A graphite powder suitable for a negative electrode material of a lithium ion secondary battery which assures a high discharging capacity not lower than 320 mAh/g is to be manufactured at a lower cost. Specifically, a graphite powder containing 0.01 to 5.0 wt % of boron and having a looped closure structure at an end of a graphite c-planar layer on the surface of a powder, with the density of the interstitial planar sections between neighboring closure structures being not less than 100/&#x3bc;m and not more than 1500/&#x3bc;m, and with dbeing preferably not larger than 3.3650 &#x212b;, is manufactured by (1) heat-treating a carbon material pulverized at an elevated speed before or after carbonization for graphization at temperature exceeding 1500&#xb0; C. or by (2) heat-treating the carbon material pulverized before or after carbonization at a temperature exceeding 1500&#xb0; C. for graphization and subsequently further heat-treating the graphized material at a temperature exceeding a temperature of the oxidating heat treatment and the heat treatment in the inert gas.

Graphite powders suited for negative electrode material of lithium ion secondary battery

The present invention enables to obtain both of a cycle characteristic and a high load characteristic. The present invention discloses a positive electrode active material containing lithium composite manganese oxide having a spinel structure for a non-aqueous electrolyte cell and a non-aqueous electrolyte cell using this material. The lithium composite manganese oxide having spinel structure has its primary particle diameter not less than 0.05 &#x3bc;m and not greater than 10 &#x3bc;m, forming an aggregate, and a specific surface measured by the BET method in a range not less than 0.2 m/g and not greater than 2 m/g.

Positive electrode active material for a non-aqueous electrode cell and non-aqueous electrode cell using the same

A nonaqueous electrolyte secondary battery is provided with a positive electrode including a positive-electrode active material, a negative electrode including a negative-electrode active material, and a nonaqueous electrolyte solution. The negative electrode further includes carbon fibers and carbon flakes. The synergistic effects of the improved retention of the electrolyte solution by the carbon fibers and the improved conductivity between the active material particles by the carbon flakes facilitate doping/undoping of lithium in a high-load current mode and increase the capacity of the battery in the high-load current mode.

Non-aqueous electrolyte secondary battery having a negative electrode containing carbon fibers and carbon flakes

A graphite powder suitable for a negative electrode material of a lithium ion secondary battery which assures a high discharging capacity not lower than 320 mAh/g is to be manufactured at a lower cost. Specifically, a graphite powder containing 0.01 to 5.0 wt % of boron and having a looped closure structure at an end of a graphite c-planar layer on the surface of a powder, with the density of the interstitial planar sections between neighboring closure structures being not less than 100/&#x3bc;m and not more than 1500/&#x3bc;m, and with dbeing preferably not larger than 3.3650 &#x212b;, is manufactured by (1) heat-treating a carbon material pulverized at an elevated speed before or after carbonization for graphization at temperature exceeding 1500&#xb0; C. or by (2) heat-treating the carbon material pulverized before or after carbonization at a temperature exceeding 1500&#xb0; C. forgraphization and subsequently further heat-treating the graphized material at a temperature exceeding a temperature of the oxidating heat treatment and the heat treatment in the inert gas.

Nonaqueous electrolyte secondary battery having a negative electrode containing carbon fibers and carbon flakes

In a non-aqueous electrolyte secondary battery including anode and cathode consisting of material capable of doping/undoping of lithium, and non-aqueous electrolytic solution in which electrolyte is dissolved in non-aqueous solvent, flaky graphite having high crystallinity and high electron conductivity is added as conductive agent into the anode and the cathode. Further, granulated carbon or carbon black having specific material property is added as conductive agent in addition to the flaky graphite. Thus, non-aqueous electrolyte secondary battery having long cycle life time and high reliability can be obtained.

Non-aqueous electrolyte secondary battery

Disclosed is a non-aqueous electrolyte secondary battery having an excellent preservation characteristic at a high temperature and charging/discharging cycle characteristic. A rolled body in which a strip-shape positive electrode and negative electrode are rolled with a separator in-between is provided inside a battery can. The positive electrode contains LiMnMaO(where, Ma is at least one element selected from the group consisting of metal elements other than Mn, and B) and LiNiMbO(where, Mb is at least one element selected from the group consisting of metal elements other than Ni, and B). By replacing part of Mn and Ni with other elements, the crystal structure can be stabilized. Thereby, the capacity retention ratio after preservation at a high temperature, and a heavy load discharging power under a high electric potential cutoff can be improved. The mean particle size of particles of the above-mentioned oxides are preferable to be 30 &#x3bc;m and below so that an excellent charging/discharging cycle characteristic can be obtained.

Material for positive electrode and secondary battery

A nonaqueous electrolyte secondary battery comprises a cathode having a cathode active material capable of electrochemically doping/dedoping lithium, an anode having an anode active material capable of electrochemically doping/dedoping lithium and a nonaqueous electrolyte interposed between the cathode and the anode. The nonaqueous electrolyte includes at least one or more kinds of vinylene carbonate, methoxybenzene compounds or antioxidants. The nonaqueous electrolyte secondary battery has a good cyclic characteristic under any environment of low temperature, ambient temperature and high temperature.

Nonaqueous electrolyte secondary battery including vinylene carbonate and an antioxidant in the electrolyte

A trade-in battery system for purchasing used secondary batteries and selling the charged used secondary batteries, wherein the trade-in battery system comprises a purchasing step, a pre-storage deterioration inspection step, a charging step, a storage step, a packaging step, and a selling step.

Trade-in battery system

Growing community of inventors

Fukushima, Japan

Masayuki Nagamine