| 摘要 |
PURPOSE:To obtain an explosion proof function without increase in the number of parts and without making an assemble process complex by forming a breakable part in a specified range in the whole circumference by welding thin. CONSTITUTION:The opening of a can 2 and the circumference of a sealing cover 10 are welded with two laser beams 14a, 14b by rotating a battery at a constant speed with a beam irradiating position fixed. A welding range and welding thickness are controlled by adjusting the irradiation time and output of the beam. Even if the internal pressure of a battery is abnormaly increased, the battery is prevented from explosion by safely operating an explosion proof function. The battery can be assembled efficiently same as a battery having no explosion proof function by somewhat changing laser welding conditions. Increase in parts and additional machining of parts are not required to forming the explosion proof function. |
