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Red lead for lead–acid batteries

The majority of industrial battery manufacturers are using red lead in their positive active material to cut down on both the consumption of energy during the formation as well as to shorten the formation time for the cells. Over the past decade, red lead has been increasingly used in automotive batteries to reduce the formation time and energy. In particular for Enhanced Flooded Batteries (EFBs) and valve-regulated absorptive glass-mat (AGM) batteries, different grades of red lead in combination with Barton or ball-mill oxide are favoured to achieve the desired performance. Two years ago, PENOX set up a program to identify the red lead-to-battery oxide ratio in combination with the optimum red lead particle-size distribution (PSD) to enhance significantly the performance of industrial and automotive batteries. Based on results presented in a research report of Matsushita Electric Industrial Co. Ltd. from the late 1990s, PENOX worked on the effect of different red lead oxidation levels, PSD and also the deviation of acid absorption values in relation to the tamped density. Early trials showed some interaction between red lead and battery oxides that affect the battery performance, especially under different states-of-charge (17.5% DoD) and life-time performance tests (50% DoD). As PENOX Korea can produce a wide range of different red lead grades and battery oxides using Barton reactor technology, a Design of Experiment methodology (DoE) was used for the most important variables to reduce the overall number of tests. Paste preparation, curing of the positive plates, active-material characterisation (XRD, porosity, etc.) and all relevant electrical tests were carried out in our R&D laboratory located in our factory in Germany. Based on the preliminary trials, a strong relationship between the particle-size distribution, the oxidation level of the red lead and the battery performance has been identified. The red lead production process and therefore the type of red lead added to the positive paste is significant. This has enabled identification of the most suitable grade of red lead for most of the battery requirements according to the battery oxide in use. The outcome of this research provided the opportunity to produce red lead grades in the PENOX factory at YeongCheon, South Korea, that are most suitable for the battery oxide produced by the battery customer to deliver the optimum battery performance.

Ian Klein

Head of Battery Additives, PENOX GmbH

Ian Klein Ian is chemist and has a master’s degree in environmental science. Late in 1999, he joined Penarroya Oxide in Cologne to assume the position of Quality and Laboratory Manager. His research and development work finally resulted in the tetrabasic lead sulfate seeding material TBLS+. At the end of 2015, Ian became the Head of Battery Additives for PENOX GmbH in Germany.