Electrode tab for a nonaqueous electrolyte secondary battery and method of forming the same
First Claim
1. A nonaqueous electrolyte secondary battery having a cylindrically shaped battery element comprising positive and negative electrodes and a separator sandwiched between said positive and negative electrodes, each of said positive and negative electrodes having an active material free region, on which no active material is applied, said active material free region having a projecting edge region which projects or extends beyond a first side edge of said separator,wherein a first end of said cylindrically shaped battery element comprises said projecting edge region of said active material free region of one of said positive and negative electrodes, and said first end of said cylindrically shaped battery element has a depressed portion, wherein an electrode tab has a first portion engaged within and welded to said depressed portion and a second portion electrically in contact with an electrode terminal, and wherein said active material free region of said one of said positive and negative electrodes is laminated with a porous sheet having substantially the same thickness as a layer of said active material.
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Accused Products
Abstract
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.
63 Citations
13 Claims
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1. A nonaqueous electrolyte secondary battery having a cylindrically shaped battery element comprising positive and negative electrodes and a separator sandwiched between said positive and negative electrodes, each of said positive and negative electrodes having an active material free region, on which no active material is applied, said active material free region having a projecting edge region which projects or extends beyond a first side edge of said separator,
wherein a first end of said cylindrically shaped battery element comprises said projecting edge region of said active material free region of one of said positive and negative electrodes, and said first end of said cylindrically shaped battery element has a depressed portion, wherein an electrode tab has a first portion engaged within and welded to said depressed portion and a second portion electrically in contact with an electrode terminal, and wherein said active material free region of said one of said positive and negative electrodes is laminated with a porous sheet having substantially the same thickness as a layer of said active material.
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10. A method of bonding an electrode tab to one side of a cylindrically shaped battery element of a nonaqueous electrolyte secondary battery, said method comprising the step of:
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forming a cylindrically shaped battery element comprising positive and negative electrodes and a separator sandwiched between said positive and negative electrodes, each of said positive and negative electrodes having an active material free region, on which no active material is applied, said active material free region having a projecting edge region which projects or extends beyond a first side edge of said separator, so that a first end of said cylindrically shaped battery element comprises said projecting edge region of said active material free region of one of said positive and negative electrodes;
forming cutting lines extending through said projecting edge region by laser irradiation of said projecting edge region to form plural fragmentary cut parts of said projecting edge region defined by said cutting lines;
bending said plural fragmentary cut parts toward a direction parallel to a plane of said first end of said cylindrically shaped battery element to form a depressed portion on said first end of said cylindrically shaped battery element;
placing a first portion of an electrode tab within said depressed portion; and
welding said first portion of said electrode tab to said depressed portion. - View Dependent Claims (11, 12, 13)
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Specification