To provide a laser welding method capable of reducing the energy density of laser beams and reducing the distance between the laser irradiation position and the content while preventing occurrence of defective quality due to the welding when welding a container storing the content.
A flange part 1b and a lid 2 of a battery case 1 to store an electrode body 3 are sealed by using laser welding. The energy density of laser beams 5 to be irradiated is set so as to give the calorie to generate a weld part 6 of sufficient depth to ensure the desired welding strength. The irradiation position of laser beams 5 is determined at the position away from the electrode body 3 by the distance Lc so that the electrode body 3 is not deteriorated by the heat effect even when the calorie given for the welding is transferred to the electrode body 3.
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