Second battery and method of producing the same
AssigneeSanyo Electric Co., Ltd.
InventorsRyoichi Wakimoto, Masakazu Yamada
Life of this patent
Estimating the term…
Abstract
A method of producing a second battery includes performing resistance welding to melt a projection formed on a connecting surface of a junction of a negative-electrode current collector and an exposed negative-electrode-core portion formed of stacked layers and form a weld nugget such that the section of the weld nugget that is perpendicular to the direction in which the layers of the exposed negative-electrode-core portion are stacked is oblong, while the projection is in contact with the outermost surface of the exposed negative-electrode-core portion in the direction in which the layers are stacked.
Claims13
A method of producing a secondary battery,
- the secondary battery including a flat electrode body including a positive-electrode sheet and a negative-electrode sheet, and a battery case containing the electrode body therein, wherein at least one of the positive-electrode sheet and the negative-electrode sheet includes a core and an active material mixture layer formed on the core, the core includes an exposed core portion at which the core is exposed, the exposed core portion is connected to a current collector member, and the current collector member includes a junction connected to the exposed core portion and a connecting surface provided on the junction such that the connecting surface faces the exposed core portion,
- the method comprising:
- performing resistance welding to melt a projection and the exposed core portion and form a weld nugget, while the projection is in contact with an outer surface of the exposed core portion formed of stacked layers, the projection being formed on the connecting surface of the current collector member before the current collector member is connected to the exposed core portion,
- wherein a section of the weld nugget that is perpendicular to a direction in which the layers of the exposed core portion are stacked is oblong, when an area of the section of the weld nugget is at a maximum.
A secondary battery comprising:
- a wound electrode body obtained by winding a positive-electrode sheet and a negative-electrode sheet with a separator interposed therebetween;
- an exterior body that has an opening and contains the wound electrode body;
- a sealing plate that seals the opening;
- and
- a positive terminal and a negative terminal that are secured to the sealing plate,
- wherein at least one of the positive-electrode sheet and the negative-electrode sheet includes a core and an active material mixture layer formed on the core,
- wherein the core includes an exposed core portion at which the core is exposed,
- wherein the exposed core portion is connected to a current collector member,
- wherein the current collector member includes a junction connected to the exposed core portion,
- wherein the current collector member is connected to an outer surface of the exposed core portion formed of stacked layers,
- wherein a weld nugget is formed at the junction between the current collector member and the exposed core portion, and
- wherein a section of the weld nugget that is perpendicular to a direction in which the layers of the exposed core portion are stacked is oblong, when an area of the section of the weld nugget is at a maximum, and a width of the section of the weld nugget in a direction in which a winding axis of the wound electrode body extends is smaller than a width of the junction in the direction in which the winding axis extends.
Dependencies are inferred from the claim text.