Mitsubishi Chemical Corporation

Yuukichi Kobayashi

Kazuo Niwa

Kenji Watanabe

Hidehiko Ohara

Isao Kaneko

Tomikazu Koyama

Minoru Inoue

Nobuyoshi Hirokou

A lithium secondary cell wherein a carbon material treated with a fluorinating agent and having substantially no C--F covalent bond, is used as an active material for negative electrode, provides a secondary cell having improved cell life. Further, a lithium secondary cell wherein a carbon material treated with a fluorinating agent and having an amount of fluorine extractable with an aqueous alkaline solution being at most 0.05 wt %, is used as an active material for negative electrode, or a lithium secondary cell wherein a carbon material treated with a fluorinating agent and containing lithium, is used as an active material for negative electrode, provides a secondary cell which is free from a problem of expansion of the casing during charging due to fluorine remaining in a small amount in the cell.

Lithium secondary cells and methods for preparing active materials for

A lithium ion secondary cell comprises a plurality of single cells composed of a collector comprising positive electrodes composed of a metallic material coated with a positive electrode active substance; negative electrodes composed of a metallic material coated with a negative electrode active substance; separators interposed between the positive and negative electrodes; lugs of the metallic materials where the active substance is not coated; and conductors adapted to bunch and clamp the lugs of the positive and negative electrodes separately, the positive and negative electrodes being assembled in laminate alternatively, and the ends of the lugs of the positive and negative electrodes being welded to the respective conductors separately so that electric current can be taken out through the conductors.

Lithium ion secondary cell

A lithium secondary cell wherein a carbon material treated with a fluorinating agent and having substantially no C-F covalent bond, is used as an active material for negative electrode, provides a secondary cell having improved cell life. Further, a lithium secondary cell wherein a carbon material treated with a fluorinating agent and having an amount of fluorine extractable with an aqueous alkaline solution being at most 0.05 wt %, is used as an active material for negative electrode, or a lithium secondary cell wherein a carbon material treated with a fluorinating agent and containing lithium, is used as an active material for negative electrode, provides a secondary cell which is free from a problem of expansion of the casing during charging due to fluorine remaining in a small amount in the cell.

A power source switching system for electric motor vehicles comprises a plurality of secondary cell units as a power source, one or more discriminating sensors for detecting vehicle information, a control device for accepting a signal from the sensors and a switching circuit for switching the connection state of the plurality of secondary cell units, responsive to a control signal issued by the control device. In one embodiment of the invention, the discriminating sensor detects the occurrence of an impact shock, with the switching circuit changing the connection state of the plurality of secondary cell units into a parallel connection to prevent short circuiting. In another embodiment of the invention, the discriminating sensor detects whether the vehicle is operating in a running mode, an inertia running mode or a regenerative braking mode respectively, with the switching circuit changing the connection state of the plurality of secondary cell units from a serial connection to a parallel connection or from a parallel connection to a serial connection in accordance with the control signal generated by detecting the operating mode, to prevent overcharging cycles which are detrimental to cell life.

Power source switching system for electric motor vehicles

An electrode support in a multilayer cell, comprises an electrode material coating portion and an electrode lead portion which are formed integrally from a metal sheet, wherein a plurality of electrode lead portions are formed integrally with said metal sheet. In such electrode support, the process for joining each of the electrode lead portions is accomplished by folding the sheet in an extremely easy manner.

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Tokyo, Japan

Yuukichi Kobayashi