Studies by the Advanced Lead-Acid Battery Consortium (ALABC) after 2001 showed that adding carbon to the negative plate (either as a separate component or a powder) helped to overcome rapid sulfation of lead–acid batteries when cycled at high rate partial state of charge, a duty that is encountered in hybrid electric vehicles (HEVs). Carbon suppresses the selective formation and growth of lead sulfate crystals in the negative plate. Laboratory and road testing have demonstrated that carbon-enhanced batteries (lead–carbon, LC) offer the specific energy, specific power, charge-acceptance and cycle-life that are required for reliable operation in start–stop, micro- and mild- HEVs. Accordingly, LC batteries and can be used instead of nickel metal-hydride or lithium-ion chemistries. The first LC battery, the UltraBattery®, was conceived by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and is now manufactured by both Furukawa and East Penn. It is a combined battery and supercapacitor in which a carbon plate of high surface-area operates in tandem with the negative plate. At present, most battery companies include a carbon additive in the negative plates of batteries designed for service in start–stop vehicles. In other innovative designs, carbon nanotubes or graphene additives have been employed, or carbon replaces part of the grid or the entire plate.
Carbon is not, however, always effective. For instance, if not properly selected and treated, carbon additives can trigger water loss, interaction with the expander and other additives, and reduction in capacity or cold-cranking power. Optimization of expanders, additives, grid and cell design is also essential for reaching a combined target of 1500 W kg-1, 60 Wh kg-1 and thousands of cycles at low cost. Advanced battery monitoring systems and optimized charge strategies are other important considerations.

Boris Monahov
Program Manager, Advanced Lead-Acid Battery Consortium

Biography: Boris Monahov is Program Manager of the Advanced Lead-Acid Battery Consortium (ALABC). The ALABC is a program of the International Lead Zinc Research Organization (ILZRO) and is managed by the International Lead Association (ILA) in London. Boris is responsible for planning and managing the Research & Development program for advanced lead-acid (lead-carbon) batteries, as well as for organizing battery demonstrations in applications like hybrid electric vehicles and energy storage systems.

Boris holds a Master’s Degree in Physics from the University of Sofia, and a PhD degree in Electrochemistry from the Bulgarian Academy of Sciences.

He has published over 60 articles and three patents. In 2014 he was awarded the Gaston Plante Medal of the Bulgarian Academy of Sciences for fundamental contributions to lead-acid battery science and technology.

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