In 2014, over 10 million start–stop vehicles were powered by advanced lead– acid batteries and this number is expected to grow to 34 million in 2017. Both automotive and advanced stationary applications place a strong demand for improved battery performance and thereby create a significant opportunity for innovation and step-change developments. Carbon additives are becoming broadly adopted in the formulation of such batteries for start–stop cars, remote telecommunication and energy-storage applications. The additives have a pronounced effect on reducing negative-plate sulfation and provide significant improvement in cycleability and dynamic charge acceptance for both valve-regulated and flooded lead–acid batteries.

Cabot has developed several PBX grades of carbon additives for negative-plate formulations. The controlled surface-area, morphology and surface chemistry of the PBX grades can deliver significant improvements in charge-acceptance and cycle-life under various testing protocols and battery configurations. A PBX135 carbon additive has been introduced along with a novel lignosulfonate expander by Borregaard Lignotech. This formulation substantially improves ‘enhanced flooded batteries‘ (EFBs) for start–stop cycling protocols by providing excellent dynamic charge-acceptance and cold-cranking performance, while managing water loss on overcharge. The presentation will describe a study of PBX135 for optimizing EFBs at the cell level, together with fundamental analysis of lead–carbon electrode morphology and a description of the key parameters that affect performance under continuous 17.5% DoD cycling and dynamic charge-acceptance protocols. In addition, from monitoring changes in lead–carbon morphology during cycling and water loss on overcharge tests are developed to provide a new level of understanding of the role of carbon and expander in achieving an optimum electrode structure.

Paolina Atanassova
Cabot Corporation
Global Applications Development Manager

Biography: Paolina Atanassova has a PhD in Chemistry from Sofia University, Bulgaria. Between 2003 and 2013, she was R&D Project Manager at Cabot Superior Micro Powders (CSMP), a division of Cabot Corporation. Her work was focused on the development of new materials for a variety of energy-storage devices such as fuel cells and batteries. Since 2010, Paolina led the development of novel carbon additives for advanced lead–acid batteries. She has published over 50 technical papers and presentations, and over 70 granted US and foreign patents. In April 2014, Paolina became the Global Application Development Manager for battery operations in Cabot’s Performance Materials Business.

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