USE OF POLYPROPYLENE FOR
CASINGS OF LEAD-ACID BATTERIES

picture of both types of battery cases

With its greater strength and lighter weight, batteries with a prolypropylene case have greater volumetric efficiency which leads to more storage capacity. Larger view.

Since the early 1920’s, battery case and covers were made by compression molding highly filled resin rubber mixtures. Fillers were coal dust, anthracite dust, clay, rags, waste paper, or whatever else was locally available. The result was heavy, porous, brittle, and were reliable battery cases and covers. During the l960’s, the Globe Battery Company developed the thin wall injection molded polypropylene battery case and cover.Using this material reduced the weight and bulk of the battery case and cover thus gave it the capability of greater energy content in a lighter weight battery. This was achieved after several years of development and the unique features of both the mold and final product were patented. This accomplishment continues to have significant value in view of needs of lightweight fuel efficient vehicles. All automobiles today contain these polypropylene batteries.

illustration comparing the two types of battery cases

Comparison dramatically
demonstrates the improvement.

The development of the thin wall, high strength polypropylene battery represented a major milestone within the history of the battery industry. In the words of one of their largest worldwide competitors, "Globe’s development of the thin wall polypropylene battery dragged the battery industry kicking and screaming into the 20th century." This Globe patented development is now a world standard. Licensees of their technology include most large battery manufacturers in the United States, as well as in several other countries. The change reduces battery weight by approximately seven pounds and an increase in the storage capacity by better space utilization of 10-20%. Using the material is no longer considered a distinguishing feature for a battery.

Globe Battery still operates today as a part of Johnson Controls, which acquired it in 1978, and maintains its lead in both technology and market share that were solidified by using polypropylene cases.