Nec Corporation

Tsuyoshi Kitami

Hiromi Suzuki

Takayuki Inoi

Susumu Saito

Satoru Tagami

Koichi Zama

Kiyokazu Isobe

A nonaqueous electrolyte secondary battery having a cylindrically shaped battery element includes positive and negative electrodes and a separator sandwiched between the positive and negative electrodes. Each of the positive and negative electrodes has an active material free region, on which no active material is applied. The active material free region has a projecting edge region which projects or extends beyond a first side edge of the separator, wherein a first end of the cylindrically shaped battery element includes the projecting edge region of the active material free region of one of the positive and negative electrodes, and the first end of the cylindrically shaped battery element has a depressed portion. An electrode tab has a first portion engaged within and welded to the depressed portion and a second portion electrically in contact with an electrode terminal.

Electrode tab for a nonaqueous electrolyte secondary battery and method of forming the same

The present invention provides a nonaqueous electrolyte secondary battery comprising: a battery case; a battery element accommodated in the battery case, the battery element comprising laminations of a first polarity type electrode, a second polarity type electrode and a separator sandwiched between the first polarity type electrode and the second polarity type electrode, the first polarity type electrode comprising a first polarity type collector which is provided with at least a first polarity type electrode active material layer except for a first side region extending along one side of the first polarity type collector, and the second polarity type electrode comprising a second polarity type collector which is provided with at least a second polarity type electrode active material layer except for a second side region extending along one side of the second polarity type collector, the first side region of the first polarity type collector projecting from first side edge of the separator and the second side region of the second polarity type collector projecting from second side edge of the separator, so that the battery element has a bottom portion which comprises the first side region of the first polarity type collector and a top portion which comprises the second side region of the second polarity type collector; a bottom conductive elastic material on a bottom of the battery case, and the bottom conductive elastic material being in contact with a substantially entire part of the bottom portion of the battery element; and a top conductive elastic material on a top of the battery case, and the top conductive elastic material being in contact with a substantially entire part of the top portion of the battery element.

Nonaqueous electrolyte secondary battery

A piezoelectric transformer includes strip form electrodes on opposing upper and lower surfaces of a piezoelectric ceramic plate formed by screen printing using a conductive paste. By using strip form electrodes, discharge of a driving portion during polarization, degradation of reliability of mechanical strength due to excessive stress in a power generating portion during polarization, and instability of transformer output due to breakage of the electrode is prevented.

Piezoelectric transformer

There is provided a piezoelectric transformer including (a) a cylindrical body made of piezoelectric material and longitudinally defining a driven section and a voltage generating section, the voltage generating section being polarized in one of directions in a direction of a longitudinal axis of the cylindrical body, (b) a pair of first electrodes formed at a curved surface of the cylindrical body in the driven section and defining a plurality of regions in the driven section in a direction of a longitudinal axis of the cylindrical body, the first electrodes being electrically isolated with each other, the regions being polarized so that every other regions are polarized in opposite directions in a direction of a longitudinal axis of the cylindrical body, the pair of first electrodes comprising a plurality of strip-shaped electrodes wound around the cylindrical body and disposed in parallel with one another in a direction of a longitudinal axis of the cylindrical body, every other strip-shaped electrodes being in electrical communication with one another so that they have a common voltage, and (c) a second electrode cooperating with one of the first electrodes located closer to the voltage generating section to make a pair therewith. In accordance with the above mentioned piezoelectric transformer, it is possible to prevent edges of a piezoelectric body from being chipped, because of its cylindrical shape. Thus, it is also possible to prevent destruction of a transformer originated from chipping thereof, resulting in higher reliability of a piezoelectric transformer.

Growing community of inventors

Tokyo, Japan

Tsuyoshi Kitami