| 摘要 |
PURPOSE: To provide a welding method of a sealed vessel of a square battery by which a fitting part having a straight line-shaped side part and a corner part having a prescribed radius of curvature can be excellently welded by a laser over its whole circumference. CONSTITUTION: A cover plate 2 composed of a metallic plate is fitted in an opening of a square case 1 composed of a straight line-shaped side part 31 and a corner part 32 having a prescribed radius of curvature, and a fitting part 3 is welded by a laser, and a sealed vessel of a square battery is formed. In first constitution, a radius of curvature of a locus (either a continuous locus or a sporadic locus) of the spot center of a laser beam is made smaller than a radius of curvature of the corner part 32 of the fitting part 3. In second constitution, laser output at welding time of the corner part 32 of the fitting part 3 is reduced more than laser output at welding time of the side part 31 of the fitting part 3. In third constitution, laser beam scanning speed at welding time of the corner part 32 of the fitting part 3 is increased more than laser beam scanning speed at welding time of the corner part 31 of the fitting part 3. |
