Packaging Design and Assembly for Ultrahigh Energy Density Microbatteries

For commercially available lithium ion batteries, the package structures can account for as much as 70% of its volume. In a multiyear effort, we have developed designs, fabrications, and assembly processes for ultrahigh energy density microbatteries of 5 and 1 mm3. Over the course of the research, the packaging system evolved due to changes or limitation specific to the battery system itself. During the study, improvements in the construction of the housing for the cathodes were made. Anodized aluminum cans fabricated through our in-house micromachining facility replaced the electroformed gold cans used in earlier experiments. Throughout the iteration of the can design, a flange around its open end, which would be used for sealing, was present, and both designs were fabricated as arrays. The ability to fabricate the housings in an array format lends it to be implemented into a scalable production assembly process. Materials evaluated for the cover ranged from copper foil to the final design of metalized s...