| 摘要 |
PROBLEM TO BE SOLVED: To provide a sealed battery which can improve the weld quality of a laser welded junction between an encapsulation cap and a lid without slowing down a welding speed.SOLUTION: A lithium ion secondary battery 50 includes an encapsulation cap 10 which is fitted to a lid 20 of a battery case 30 to seal an electrolyte injection port 23 formed in the lid 20, where a space S is formed between the encapsulation cap 10 fitted to the lid 20 and the electrolyte injection port 23, and the encapsulation cap 10 has its peripheral edge joined to the lid 20 by laser welding. A joining face 11 on the peripheral edge of the encapsulation cap 10 and a joining face 21 of the lid 20 are respectively formed so that a gap G between the joining face 11 on the peripheral edge of the encapsulation cap 10 and the joining face 21 of the lid 20 gradually increases as it goes downwards, and a groove 12 communicating between the gap G and the space S is formed at the bottom of the encapsulation cap 10. |
