Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Hiroki Muraoka

Shoichiro Watanabe

Tsumoru Ohata

Shinji Kasamatsu

Yoshiaki Nitta

Takayuki Shirane

Shigeo Kobayashi

Takafumi Fujiwara

Hiroshi Matsuno

Kazushige Kinoshita

Hiroaki Furuta

Takeshi Fukumasa

Kyoushige Shimizu

A secondary battery having an electrode assembly in which strip-shaped positive and negative electrode plates are spirally wound with a strip-shaped separator interposed therebetween, the positive and negative electrode plates comprising a current collector and a material mixture layer carried thereon. The positive electrode plate has, in a vicinity of a first end at an initial winding side, an exposed portion of the positive electrode current collector having no positive electrode material mixture formed thereon and a positive electrode lead connected to the exposed portion. A first winding turn outwardly adjacent to a connecting portion of the positive electrode lead with the separator interposed therebetween and a second winding turn outwardly adjacent to the first winding turn with the separator interposed therebetween comprise a portion of the negative electrode plate carrying the negative electrode material mixture layer.

Secondary battery

Using a graphite material capable of intercalating and de-intercalating lithium ions as the anode, the peak intensity ratio R(&equals;I(110)/I(004)) corresponding to lattice planes (110) and (004) of graphite material obtained by wide angle X-ray diffraction measurement of this anode is in a range of 0.05 to 0.5. Hence, edges of graphite crystals exist adequately on the electrode surface at the interface to the electrolyte, and therefore intercalation of lithium proceeds smoothly, polarization at the time of charging and discharging is suppressed, and a nonaqueous electrolyte secondary battery excellent in high rate discharging characteristic is obtained. The obtained battery is small in deterioration if charging and discharging are repeated.

Nonaqueous electrolyte secondary battery and its anode

A nonaqueous secondary battery has high energy density and excellent charging and discharging cycle characteristic. The constitution includes (a) a positive electrode having a positive electrode substance, (b) a negative electrode having an carbon fluoride, and a carbon material, and (c) an electrolyte solution. The positive electrode substance is capable of releasing and occluding lithium ions in charging and discharging, the carbon material is capable of occluding and releasing the lithium ions in the charging and discharging, the carbon fluoride is capable of reacting chemically with the lithium ions, and the electrolyte solution is a nonaqueous electrolyte solution. The carbon fluoride is expressed by chemical formula (C.sub.x F).sub.n.

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Osaka, Japan

Hiroki Muraoka