Hermetic cell and method for producing same
A hermetic cell excellent in weld strength is provided. The hermetic cell includes an can having an opening and a seal for sealing the opening of the can. A portion of engagement of the seal with the opening of the can is welded with a high energy beam, thereby hermetically sealing the can. At least one portion of a melt mark resulting from the high energy beam welding has a top surface having a lowermost point lower in a direction of a bottom of the can than a lowermost point of a top surface of an adjacent portion of the melt mark. The at least one portion of the melt mark has a bottom surface having a lowermost point lower in the direction of the bottom of the can than an lowermost point of a bottom surface of the adjacent portion of the melt mark.
1. A hermetic cell comprising:
a can having an opening; and
a seal for sealing the opening of the can, wherein:
a portion of engagement of the seal with the opening of the can is welded with a high energy beam, thereby hermetically sealing the can;
at least one portion of a melt mark resulting from the high energy beam welding has a top surface having a lowermost point lower in a direction of a bottom of the can than a lowermost point of a top surface of an adjacent portion of the melt mark; and
the at least one portion of the melt mark has a bottom surface having a lowermost point lower in the direction of the bottom of the can than a lowermost point of a bottom surface of the adjacent portion of the melt mark;
the lowermost point of the top surface of the at least one portion of the melt mark is from 0.05 to 0.2 mm lower in the direction of the bottom of the can than the lowermost point of the top surface of the adjacent portion of the melt mark; and
the lowermost point of the bottom surface of the at least one portion of the melt mark is at least 0.1 mm lower in the direction of the bottom of the can than the lowermost point of the bottom surface of the adjacent portion of the melt mark.
2. The hermetic cell according to claim 1 , wherein:
the can is rectangular; and
the lower portion of the melt mark is formed at least in a corner portion of the portion of engagement subjected to the high energy beam welding.
3. The hermetic cell according to claim 1 , wherein:
the can is rectangular; and
an external electrode terminal is provided in a center portion of the seal; and
the lower portion of the melt mark is formed at least in a terminal lateral portion (T) of the seal.
4. The hermetic cell according to claim 2 , wherein:
the can is rectangular; and
an external electrode terminal is provided in a center portion of the seal; and
the lower portion of the melt mark is formed at least in a terminal lateral portion (T) of the seal.