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US 2008/0305393 A1Published application
Lithium-ion secondary battery
AssigneeHitachi Vehicle Energy, Ltd.
InventorsKenji NAKAI, Akinori TADA, Seiichi SATO, Masatsugu ARAI
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AssigneeHitachi Vehicle Energy, Ltd.
InventorsKenji NAKAI, Akinori TADA, Seiichi SATO, Masatsugu ARAI
Estimating the term…
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 disks 7 are disposed so as to face both end faces of the winding group, respectively. The current collecting disk 7 has projecting ridge portions 8 on a face thereof opposite to the winding group and flat face portions facing the winding group at positions corresponding to the projecting ridge portions 8. The projecting ridge portions 8 are 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 disks 7 and joining is performed by irradiating the projecting ridge portions 8 with laser beam. The flat face portions of the current collecting disks 7 abut 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.
A lithium-ion secondary battery which is provided with a electrode group where a positive electrode plate obtained by applying positive electrode mixture mainly including positive electrode active material to a foil and a negative electrode plate obtained by applying negative electrode mixture mainly including negative electrode active material to a foil are disposed so as to sandwich a separator, where an end portion of the foil of at least one of the positive electrode plate and the negative electrode plate projects from an end face of the electrode group, a current collecting member for collecting current from the foil of said at least one is disposed so as to face the end face of the electrode group, and a joint portion obtained by joining the current collecting member and an end portion of the foil is formed so as to project from a face of the current collecting member which faces the electrode group, wherein the current collecting member includes a plurality of projecting ridge portions extending from a central portion of the current collecting member toward an outer edge portion thereof on a face thereof positioned on the side opposite to the electrode group and flat portions facing the electrode group and provided at positions corresponding to the projecting ridge portions, and the joint portion is formed by causing the end portion of the foil to abut on the flat portions and melting the projecting ridge portions to cause the melted projecting ridge portions to project from the flat portions.
Dependencies are inferred from the claim text.