US 9,812,676 B2
Prismatic secondary battery
Kouichi Kajiwara, Hitachinaka (JP); Hayato Koguchi, Hitachinaka (JP); Takeshi Hizono, Hitachinaka (JP); and Hiroaki Egawa, Hitachinaka (JP)
Assigned to HITACHI AUTOMOTIVE SYSTEMS, LTD., Ibaraki (JP)
Appl. No. 14/422,938
Filed by Kouichi Kajiwara, Hitachinaka (JP); Hayato Koguchi, Hitachinaka (JP); Takeshi Hizono, Hitachinaka (JP); and Hiroaki Egawa, Hitachinaka (JP)
PCT Filed Aug. 31, 2012, PCT No. PCT/JP2012/072138
§ 371(c)(1), (2), (4) Date Feb. 20, 2015,
PCT Pub. No. WO2014/033906, PCT Pub. Date Mar. 6, 2014.
Prior Publication US 2015/0228936 A1, Aug. 13, 2015
Int. Cl. H01M 2/02 (2006.01); H01M 2/04 (2006.01); H01M 10/04 (2006.01); H01M 10/0587 (2010.01)
CPC H01M 2/024 (2013.01) [H01M 2/0217 (2013.01); H01M 2/0426 (2013.01); H01M 2/0439 (2013.01); H01M 2/0473 (2013.01); H01M 10/0431 (2013.01); H01M 10/0587 (2013.01); H01M 2220/20 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A prismatic secondary battery comprising:
a battery case in a prismatic shape which includes a bottom wall part in a rectangular shape forming a bottom, a side wall part in a prismatic tubular shape forming a side wall, and an opening part being open upward at an upper end of the side wall part; and
a battery cover which is welded to the upper end of the side wall part of the battery case and seals up the opening part, wherein:
the battery cover has a blockage part which blocks up the opening part, a contact part which is in contact with the upper end of the side wall part continuously along an entire periphery at a position outside the blockage part, and a convex part which projects from the blockage part toward the bottom wall part;
cover thickness at the contact part is less than cover thickness at the blockage part, wherein the battery cover has a groove part along an inner periphery of the convex part, the groove being formed on an inner surface of the battery cover; and
the convex part is formed by use of excess volume caused at a time of formation of the contact part and the groove part and extends continuously around an entire periphery of the battery cover adjacent to an inner surface of the side wall part.