Separators for lead–acid batteries have traditionally been manufactured via the extrusion and extraction of ultrahigh molecular weight polyethylene (PE)–silica–oil mixtures to form microporous ribbed sheets, or via a paper-making process to form absorptive glass fibre mats (AGMs). In general, PE–SiO2 separators have 55–60% porosity, whereas AGM separators have 90–92% porosity. The interim porosity range has not been as widely examined, although various sol-gel, phase separation, and sintering approaches can be used to manufacture porous materials with 60–90% porosity. The presentation opens with a brief examination of the impact of PE–SiO2 composition and process technology on separator properties. There follows an evaluation of some potential new separator concepts for automotive and Industrial separators, i.e., (i) melt-blown fibre technology; (ii) compression moulding of thick polymer–silica monoliths; (iii) microporous polymer– polyester sheets; (iv) chemically crosslinked polymer gels formed directly in sulfuric acid. The potential advantages of each approach with regard to mechanical properties, oxidation resistance, electrical resistance, and battery assembly will be discussed in detail.
ENTEK International LLC
Chief Technology Officer
Dr Richard Pekala has a BS degree in biomedical engineering from Duke University (1981) and a ScD. degree in polymeric materials from the Massachusetts Institute of Technology (1984). He began his career at Lawrence Livermore National Laboratory where he conducted research for 11 years on sol-gel chemistry and organic-based aerogels. In 1996, he joined PPG Industries to advance precipitated silica for use in battery separators. Dr Pekala transferred to ENTEK in 1999 and is now the company’s Chief Technology Officer.