Method for fabricating battery cases

Claim 1

The process of injection molding a battery container having a bottom portion, a plurality of side portions, and a plurality of long thin interior wall portions, said interior wall portions being parallel to one another and to two of said side portions, the thickness of the major portion of said walls being no greater than about 0.10 inch and having a taper of no more than about 0.0025 inch per inch, comprising the steps of: a. providing a mold including a first section for forming the outer portion of said container, including said side and bottom portions, and a plurality of cores positioned with respect to said first section to form the inner portions of said side and bottom portions and the interior walls of said container, b. maintaining a rigid connection between said cores and said first sections at the portion of said cores corresponding to said bottom portions, c. injecting a thermoplastic material into said mold and disestablishing said rigid connection before said thermoplastic material hardens, d. removing only alternate ones of said cores from said mold subsequent to plastic injection and after an initial period of hardening, e. separating the remaining cores from said first section whereby said plastic remains attached to said cores and separates from said first portion, and f. removing the plastic from said cores.