3D Printed Polymer Gaskets for Custom-Form Batteries

Additive manufacturing (AM) has held promise as a means to realize customized 3D batteries, which can improve design freedom and volume utilization of products and systems. Toward this end, the 3D printing of cell active components has recently become a topic of academic and industrial interest. However, comparatively less progress has been made in the development of 3D printed cell packaging components, including cases, gaskets, and sealing strategies. In this work, we assess an array of 3D printable polymeric materials for use as gaskets in coin cells for eventual use in customized 3D printed cells. The gasket materials evaluated in this work include several thermoplastics (polylactic acid, polycarbonate, polypropylene/ polyethylene copolymer) and photocurable resins (acrylate-based photo resin and polyethylene-glycol-diacrylate-based photo resin). Each material was 3D printed in the form of a coin cell gasket, used as a gasket in a lithium-ion coin cell, and cells were cycled to evaluate gasket performance. It was found that cells using 3D printed polypropylene/polyethylene copolymer gaskets performed most favorably with capacity retention similar to cells using conventional polypropylene gaskets (less than 10% difference in discharge capacity between the two) after 100 charge/discharge cycles. Furthermore, 3-point flexural bend testing was used to evaluate the mechanical stiffness of each polymeric material before and after soaking in electrolyte solvent to evaluate the physical response of each material to the electrolyte. Polypropylene/polyethylene copolymer was found to have the most favorable physical and mechanical response to long-term electrolyte soaking. Overall, this work reveals that 3D printed polypropylene composites are highly compatible with lithium-ion battery cell packaging and that the use of alternative 3D printable polymeric materials may result in significant losses in cell performance and reliability. Progress toward the realization of custom-form cells beyond gaskets will also be shown.<br/><br/>Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This work describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the document do not necessarily represent the views of the U.S. Department of Energy or the United States Government.