Method for manufacturing nonaqueous electrolyte secondary battery
A method for manufacturing a nonaqueous electrolyte secondary battery, when an electrode tab is provided at a longitudinal-direction end portion of an electrode located at a winding-start side of an electrode body, the method being capable of sufficiently reducing damage on a separator and the electrode in a process for manufacturing the electrode body. In a manufacturing step of one example of an embodiment, a negative electrode tab is bonded to a longitudinal-direction end portion of a negative electrode to be located at a winding-start side of an electrode body, the negative electrode tab is processed so that a width-direction central portion of the negative electrode tab at least bulges toward a winding-outer side of the electrode body, and while a gap is formed between the negative electrode tab and a winding core, a positive electrode, the negative electrode, and a separator are wound around the winding core.
1. A method for manufacturing a nonaqueous electrolyte secondary battery including an electrode body in which a positive electrode and a negative electrode are wound with a separator interposed therebetween, the method comprising, in at least one of the positive electrode and the negative electrode:
a step of bonding an electrode tab to a longitudinal-direction end portion of the electrode to be located at a winding-start side of the electrode body;
a step of processing the electrode tab so that a width-direction central portion of the electrode tab along a longitudinal direction of the electrode at least bulges toward a winding-outer side of the electrode body; and
while a gap is formed between the electrode tab and a winding core, a step of winding the electrode and the separator around the winding core.
2. The method for manufacturing a nonaqueous electrolyte secondary battery according to claim 1 ,
wherein the step of processing the electrode tab forms a curved portion so that the width-direction central portion of the electrode tab along the longitudinal direction of the electrode at least bulges toward the winding-outer side of the electrode body.
3. The method for manufacturing a nonaqueous electrolyte secondary battery according to claim 2 ,
wherein the curved portion has a curvature radius R1 smaller than a radius R of the winding core.
4. The method for manufacturing a nonaqueous electrolyte secondary battery according to claim 3 ,
wherein the electrode tab is processed so that the curvature radius R1 of the curved portion satisfies (⅓)×R≤R1<R.
5. The method for manufacturing a nonaqueous electrolyte secondary battery according to claim 2 ,
wherein the curved portion is formed at the width-direction central portion of the electrode tab, and two width-direction end portions thereof are each a no-processed portion.
6. The method for manufacturing a nonaqueous electrolyte secondary battery according to claim 2 ,
wherein the electrode tab is processed so that the curved portion has a width of (⅓) of the tab width or more.