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Organic expanders play an important role in the lead–acid battery. This study presents the design of an electrochemical method which evaluates the influence of some commercial expanders on the performance of the negative plate. Examination is made of different commercial expander formulations which are prepared in the laboratory under carefully controlled conditions. | ELSEVIER Journal of Power Sources 78 1999 30-34 Electrochemical evaluation of additives for lead-acid batteries under high-discharge conditions R. Flores a L.M. Blanco b Acumuladores Mexicanos S.A. de C.V. Ave Eugenio Garza Sada 3431 Sur Monterrey 64740 Nuevo Leon México b Facultad de Ciencias Químicas UANL Cd. Universitaria San Nicolás de los Garza 66450 Nuevo Leon Mexico Received 31 July 1998 accepted 15 November 1998 Abstract Organic expanders play an important role in the lead-acid battery. This study presents the design of an electrochemical method which evaluates the influence of some commercial expanders on the performance of the negative plate. Examination is made of different commercial expander formulations which are prepared in the laboratory under carefully controlled conditions. In order to compare their influence on the behaviour of the negative plate potential step and cyclic voltammetric techniques using high-potential polarization are performed. The results allow the selection of those expander additives which exert the best electrochemical effect on high-rate discharge reactions at negative plates. 1999 Elsevier Science S.A. All rights reserved. Keywords Charge-discharge cycles Expanders Electrochemical evaluation Lead-acid battery Negative active-material 1. Introduction The economics of lead-acid batteries have led to the search for a rapid and reliable method for the evaluation of the additives which are required in the negative plates of these batteries. The additives are called expanders and their mechanism of action has been studied in detail by Pavlov 1 . It has been found that expanders of the lignosulfonate type are strongly adsorbed on the lead surface and during lead dissolution the Pb2q ions migrate through the adsorbed layer. This adsorption of the expander affects the anodic oxidation of Pb 2 the cathodic reduction of lead sulfate 3 the morphology of lead sulfate and both the porosity and the surface area of the negative-plate .
