Method for producing a sealed battery comprising a laser beam profile

A method for producing a sealed battery including:

• a battery case having a liquid inlet;
• and a sealing cover that seals the liquid inlet,
• wherein
• the method comprises:
• injecting an electrolytic solution into the battery case through the liquid inlet;
• and
• after the injecting, welding the battery case and the sealing cover by irradiating and linearly scanning a laser beam on a welding area across the battery case and the sealing cover, while the liquid inlet is closed with the sealing cover,
• the laser beam has a beam profile including:
• a first beam capable of vaporizing the electrolytic solution and oil, which exist on a surface of the welding area;
• and
• a second beam enabling keyhole welding on a removal portion of the welding area, from which at least part of the electrolytic solution and at least part of the oil have been removed by irradiation of the first beam, and
• the welding includes:
• before irradiating and linearly scanning the laser beam on the welding area where the battery case and the sealing cover are to be welded together, starting irradiating the laser beam from a first position located outside the welding area and linearly scanning the laser beam to a second position included in the welding area,
• linearly scanning the laser beam from the second position, over a half circumference of the welding area, to a third position located in the welding area,
• temporarily stopping irradiation of the laser beam at the third position,
• linearly scanning the laser beam from the third position located in the welding area, over another half circumference of the welding area, to the second position located in the welding area such that the battery case and the sealing cover are welded together over an entire circumference of the welding area, and
• resuming irradiating the laser beam at a fourth position located outside the welding area and linearly scanning the laser beam from the fourth position to the third position included in the welding area.