Hitachi Vehicle Energy, Ltd.

Vehicle Energy Japan Inc.

Hitachi Automotive Systems, Ltd.

Akinori Tada

Kenji Nakai

Kinya Aota

Masatsugu Arai

Takeshi Sato

Keiichiro Ohkawa

Yoshinori Aoshima

Hiroshi Morikawa

Kenichiro Tsuru

Seiichi Sato

Hideki Shinohara

Masatsugu c/o Mechanical Engineering Arai

Provided is a secondary battery that enables an air tightness of a battery container to be ensured with more certainty compared with a conventional one. A secondary batteryincludes a wound body, a pair of current collector plates, a battery can, a battery lid, an insulating plate, an insulating sheet, and a pair of external terminals, and an end portionof the insulating sheetadjacent to the battery lidis secured to the insulating plate

Secondary battery

A problem of the present invention is to provide a rectangular secondary battery in which heat generation of a current collecting plate is suppressed. A rectangular secondary battery of the present invention which solves the above-described problem includes: a flat wound group which is obtained by winding a positive electrode and has a positive electrode metal foil-exposed portion; a battery can which stores the wound group; a battery lid which seals the battery can; a positive electrode external terminal which is provided on the battery lid; and a positive electrode current collecting plate which electrically connects the external terminal and the wound group. The positive electrode current collecting plate includes a fixed portion fixed on the battery lid, a welded portion welded on the metal foil-exposed portion of the wound group, and a joint connecting the fixed portion and the welded portion. Further, in the current collecting plate, the joint has a width portion equal to or less than widths of the fixed portion and the welded portion and a thickness portion thicker than the fixed portion or the welded portion.

Rectangular secondary battery

A battery control apparatus is provided which can keep an inter-terminal voltage of each single cell within a permitted range while permitted power is controlled in units of a battery pack. The battery control apparatus of the invention restricts the permitted power of the battery pack according to a degree of closeness of a close circuit voltage of the single cell to an upper limit or a lower limit of the permitted range.

Battery control apparatus

A lithium ion secondary battery comprises a case; a positive electrode foil having a current collector foil on which a positive electrode material is coated; an negative electrode film having a current collector film on which an negative electrode material is coated; a separator sandwiched between the positive electrode film and the negative electrode film, the films and the separator being arranged in multiple layers to form a group of electrodes enclosed in the case, a positive collector disc plate connected to the positive electrode side of the group of the electrodes, and an negative collector disc plate connected to the negative electrode side of the group of the electrodes. Each of the current collector foils has a non-coated portion extended along one side of the foils, a part or the entire of the non-coated portion being exposed from a side of the separator. At least one of the collector disc plate is welded to the side of the exposed non-coated portion of the group of the electrodes. The periphery of the collector disc plate has an annular portion, which is bent towards the group of electrodes.

Lithium ion secondary battery

The present invention provides a lithium-ion secondary battery which can suppress internal resistance to a small value. The lithium-ion secondary battery includes a winding group obtained by winding a positive electrode plate and a negative electrode plate via a separator. An end portion of a positive electrode mixture non-application portionprojects at an upper portion of the winding group, while an end portion of a negative electrode mixture non-application portion projects at a lower portion of the winding group. Current collecting disksare disposed on both end faces of the winding group so as to face them, respectively, and materials for the current collecting disks are the same materials as those for a positive electrode current collector and a negative electrode current collector. An end portion of the positive electrode mixture non-application portionis joined to a face of the current collecting diskpositioned on the side of the winding group at a plurality of joint portions on the positive electrode side, while an end portion of the negative electrode mixture non-application portion is joined to a face of the current collecting diskpositioned on the side of the winding group at a plurality of joint portions on the negative electrode side. Some of the joint portions form joint portions taking on a width expansion shape gradually expanding from a joint end portion with the positive electrode mixture non-application portiontoward the current collecting disk. A volume of the joint portionis increased.

Lithium-ion secondary battery

A lithium-ion secondary battery where a current collecting member and a foil are joined to each other securely while damage of the foil is suppressed is provided. The lithium-ion secondary battery is provided with a winding group obtained by winding a positive electrode plate and a negative electrode plate via a separator. An end portion of a positive electrode mixture non-application portion and an end portion of a negative electrode mixture non-application portion project at an upper portion and a lower portion of the winding group, respectively. Current collecting disksare disposed so as to face both end faces of the winding group, respectively. The current collecting diskhas projecting ridge portionson a face thereof opposite to the winding group and flat face portions facing the winding group at positions corresponding to the projecting ridge portions. The projecting ridge portionsare formed radially. The end portion of the positive electrode mixture non-application portion and the end portion of the negative electrode mixture non-application portion are caused to abut on the flat face portions of the current collecting disksand joining is performed by irradiating the projecting ridge portionswith laser beam. The flat face portions of the current collecting disksabut on the end portion of the positive electrode mixture non-application portion and the end portion of the negative electrode mixture non-application portion approximately evenly.

In a secondary battery, for providing a structure which can enable a welding operation even when a gap is formed between a current collecting plate and a winding assembly, recessed portions are formed in a positive current collecting plate. The recessed portions are disposed opposite to the winding assembly. A laser beam is irradiated to welding protrusions located between the recessed portions to melt the welding protrusions. Here, since the end surface of a positive electrode foil is uneven in height, the positive electrode foil does not contact the positive current collecting plate necessarily. The welding operation is performed by heating, melting, and dropping the welding protrusions by the use of a YAG laser under the welding condition of a laser power of 900 W and a welding speed 2 m/min.

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Hitachinaka, Japan

Akinori Tada