Hitachi Maxell, Limited

Maxell Holdings, Ltd.

Hitachi Maxell Energy, Ltd.

Toshikazu Yoshiba

Noriyuki Yabushita

Koji Yamaguchi

Kenji Tsuda

Megumu Takai

Yuko Onishi

A flat battery of the present invention is a flat battery including an exterior can and a sealing can with which an opening of the exterior can is sealed, wherein the exterior can and the sealing can include a bottom portion and a circumferential wall extending upright from an outer circumference of the bottom portion and have a cylindrical shape that is open at one end; a distal end portion of the circumferential wall of the exterior can is bent toward a central axis of the sealing can to form a curve, whereby the exterior can is fixed to the sealing can by crimping; in a cross-sectional shape of the sealing can in the direction of the central axis, the circumferential wall of the sealing can is a single layer wall without being folded back, and the circumferential wall of the sealing can includes a rectilinear portion that is connected to the bottom portion via a corner portion; and an angle &#x3b8;1 formed by the bottom portion and the rectilinear portion may be greater than 90&#xb0;.

Flat battery

A flat-shaped battery of the present invention includes an outer can that is open upward, a sealing can that is open downward, and a gasket that is placed between the outer can and the sealing can to seal the space between them. The outer can includes a base plate and a cylindrical surrounding wall. The surrounding wall of the outer can includes a straight portion that extends upward and perpendicular to the base plate. The sealing can includes a housing in the form of an inverted dish, a flange that projects outward from a lower end of the opening of the housing, and a single outer surrounding wall that extends downward from an outside edge of the flange so as to be perpendicular to the flange. The outer surrounding wall of the sealing can is arranged perpendicular to the base plate of the outer can. The gasket includes a base that receives a lower end of the outer surrounding wall of the sealing can, and an outer cylindrical wall that extends upward from the base and is disposed between the surrounding wall of the outer can and the outer surrounding wall of the sealing can. The surrounding wall of the outer can has a curved edge such that the surrounding wall at the opening of the outer can is bent toward an axis of the outer can and positioned laterally with respect to the outer surrounding wall of the sealing can. The curved edge presses an upper end of the outer cylindrical wall of the gasket against an upper end of the outer surrounding wall of the sealing can.

Flat-shaped battery

A flat nonaqueous secondary battery with improved reliability is provided. The flat nonaqueous secondary battery () includes an electrode assembly disposed in a space formed by an exterior case () and a seal case (). The electrode assembly includes a plurality of positive electrodes () and a plurality of negative electrodes () alternately stacked upon each other and a separator (). The separator () has a joint () formed by welding together at least a portion of its periphery. When the separator () and the positive electrode () are measured along a cross section in their thickness direction, the ratio A/B of the shortest distance A between the end of the joint () of the separator () facing the positive electrode () and the outer periphery of the positive electrode () sandwiched by the separator () to the thickness B of the positive electrode () is not smaller than 1.

Flat nonaqueous secondary battery

An apparatus to be attached to a rotary portion includes a substrate and a flat-shaped battery buried in resin. The substrate and the flat-shaped battery are connected to each other via a terminal in such a manner that one of a positive electrode can and a negative electrode can constituting the flat-shaped battery, the can having a smaller amount of deformation caused by bulging at a time of the expansion of the flat-shaped battery, is opposed to the substrate. A surface of the flat-shaped battery having a smaller amount of deformation is opposed to the substrate, and hence, adverse effects on the apparatus, such as the displacement of the terminal and the deformation of the substrate, can be reduced even when the flat-shaped battery expands.

Method for attaching a flat-shaped battery and apparatus to be attached to a rotary portion

The flat-shaped battery includes an electrode material containing an active material, and a battery case which has the electrode material housed inside and in which a plurality of protruding members extending inwardly from an inner surface of the battery case are fixed to the inner surface. The electrode material is housed in the battery case with those individual protruding members inserted in the electrode material. As a result, even if the flat-shaped battery is subjected to such external influences as accelerations and vibrations, the electrode material can securely be prevented from moving within the battery case.

Growing community of inventors

Osaka, Japan

Toshikazu Yoshiba