tailieunhanh - Separators and organics for lead–acid batteries

This review discusses various interactions between organic compounds, brought into the lead–acid battery via the separator, and their subsequent effect on battery performance. Historically, the interrelationship started with certain ‘expander’ actions on the lead morphology due to lignins, which leached out of the wooden separators of that time. Synthetic separator materials did not show this effect, but gained acceptance as they were far more stable in the hostile battery environment. The partially hydrophobic character of synthetic separators has been overcome by organic surfactants. Other organic compounds have been found to improve further the stability of separators against oxidation. . | ELSEVIER Available online at ScienceDirect Journal of Power Sources 158 2006 1102-1105 Separators and organics for lead-acid batteries Werner Bohnstedt Daramic LLC. Erlengang 31 D-22844 Norderstedt Germany Received 16 November 2005 accepted 1 February 2006 Available online 29 March 2006 Abstract This review discusses various interactions between organic compounds brought into the lead-acid battery via the separator and their subsequent effect on battery performance. Historically the interrelationship started with certain expander actions on the lead morphology due to lignins which leached out of the wooden separators of that time. Synthetic separator materials did not show this effect but gained acceptance as they were far more stable in the hostile battery environment. The partially hydrophobic character of synthetic separators has been overcome by organic surfactants. Other organic compounds have been found to improve further the stability of separators against oxidation. Special organic molecules namely aldehydes and ketones have been identified to retard or even suppress the adverse effects of metals such as antimony and thus prolong the cycle-life of traction batteries in heavy-duty applications or reduce water loss from automotive batteries. Knowledge about these interactions has opened ways to improve separators. 2006 Elsevier . All rights reserved. Keywords Separator Oxidation resistance Surfactant Antimony poisoning Water loss Lead-acid battery 1. Introduction The separator is the distance-keeping component between the positive and the negative electrode of a galvanic cell. It does not participate directly in the electrochemical processes of electricity storage. Rather its significance lies in the technical challenge to build batteries that are ever more compact and long-lasting 1 . Deriving from this definition a separator has to serve over a long period of time as a physical separation of the electrodes without too much hindrance