Richard Pekala
Bio
Dr. Pekala is Chief Technology Officer for ENTEK Technology Holdings LLC. He has a B.S. degree in biomedical engineering from Duke University (1981) and a Sc.D. degree in polymeric materials from the Massachusetts Institute of Technology (1984). Dr. Pekala began his career at Lawrence Livermore National Laboratory where he worked for 11 years in the Materials Science Department on sol-gel chemistry and organic-based aerogels. In 1996, Dr. Pekala joined PPG Industries as a scientist working in the Silica Products business unit where he had responsibility for precipitated silica used in battery separators and synthetic printing media. In 1999, Dr. Pekala joined ENTEK where he helped to commercialize new products such as lithium-ion battery separators, Pb-acid battery separators, flow battery separators, conductive carbon films, and waterproof breathable membranes. Dr. Pekala has over 100 technical publications, 2 R&D 100 awards, and 33 patents.
ENTEK Absorptive glass mat (AGM) and polyethylene/silica are the two most common separators used in lead batteries to space the electrodes and allow for ionic conduction. These separators are not only different in composition, but the polyethylene/silica separators have ribs and ~60% porosity whereas AGM is flat and contains ~92% porosity. In this presentation, we review how silica fibres are manufactured, and then the influence of key characteristics such as fibre morphology, fibre diameter, surface area, polymer binders, and process conditions on key AGM characteristics. In particular, we will examine how the fibre diameter distribution impacts % porosity, pore size distribution, and compression-recovery in both a ‘wet’ and ‘dry’ state. Finally, we will briefly discuss the development of new AGM formulations to further mitigate acid stratification.