| 摘要 |
A joint section where covering films 2 a, 2 b of film-covered battery 1 are heat-sealed together is formed with flat surface 6 ' having thickness t<SUB>1 </SUB>and groove 6 having thickness t<SUB>2</SUB>. Groove 6 serves to reduce the projection area of film-covered battery 1 by folding side 2 c toward receiving section 2 a 1 with groove 6 serving as an edge, and groove 6 is made thinner than flat surface 6 ' by Delta t=t<SUB>1</SUB>-t<SUB>2</SUB>. Therefore, the length of covering films 2 a, 2 b produced on outer side 6 a is shortened as compared with the case of folding the portion that has thickness t<SUB>1</SUB>. |
