Prior to the start of the 13th European Lead Battery Conference in Paris on Sept. 24, 2012, ALABC members and management took part in a special workshop to discuss the issues surrounding the increasing requirements for Dynamic Charge Acceptance (DCA) for lead-acid batteries used in micro-hybrid electric vehicles.  This meeting was chaired by Geoffrey May of Focus Consulting on behalf of ILA and took the format of an introduction to the subject by four distinguished speakers followed by an open discussion. 

Eckhard Karden of Ford Europe set the scene by putting the requirements of the car companies on the table.  He was followed by Lan Lam of CSIRO in Australia who described some of the electrochemical fundamentals that limit the operation of lead-acid batteries in high-rate partial state-of-charge conditions. Following this presentation, Heide Budde-Meiwes of Aachen University showed how DCA fell to much lower levels after rest periods and was critically dependent on test protocols which are being developed to simulate conditions of service. Finally, Eberhard Meissner of Johnson Controls in Germany discussed how the battery companies are responding to the needs of the car companies.

VRLA batteries provide an effective solution, but there is pressure to develop and improve flooded batteries as Extended Life Flooded (ELF) batteries to reduce cost. There are difficult issues to resolve including acid stratification and in meeting the requirements for charge acceptance, none of the other standard characteristics of the battery should be compromised.

The open discussion that followed was facilitated by David Rand, also of CSIRO, and it was clear the needs for effective energy recovery, good cycle life and continuing pressure to improve fuel economy are making DCA a moving target for battery suppliers.  Nonetheless, lead-acid offers a much more cost-effective solution than other chemistries or energy storage devices.

The workshop was very timely ─ it served to underscore the importance of gaining an unequivocal understanding of the behavior of lead-acid batteries in micro-hybrid applications, a message that the ALABC has been emphasizing and supporting for some time.  Success will ensure that VRLA and ELF lead-acid batteries remain pre-eminent as the vehicle duty-cycle becomes more demanding.

For more information, contact Geoffrey May at [email protected].