TECHNICAL NEWSLETTER Edition 10 - June 2014
WHAT’S INSIDE MAKES ALL THE DIFFERENCE! GRIDS IN FOCUS. Any battery is only as good as its contents and every single component, starting with lead as the raw material and ending with the casing, is of decisive importance to battery quality. Therefore, strict standards must be fulfilled in order to guarantee long service life. Consequently, this “Newsletter” deals in detail with the various types of grid employed and the differing lead alloys used in commercial vehicle batteries, which face the toughest challenges of all. The grid production process. At present, four grid production processes are utilised in the battery branch: Expanded metal Positive and negative lead strip that has been rolled to the appropriate thickness is used to create a grid by means of slitting and expansion. Book Casting Grids in various thicknesses and forms are produced using differing lead alloys in a gravity casting process. Continuous Casting Grids are manufactured through the application of liquid lead onto a rotating, cooled forming roll. Punched grid The grid is punched out of a previously rolled lead strip. No advantages without disadvantages. Each of the individual manufacturing processes offers certain advantages, but also disadvantages. Indeed, productivity and qualitative characteristics do not automatically go hand in hand. For example, not every lead alloy can be used in all of the production processes. Equally, the subsequent polarity of the plate is decisive in the choice of procedure. An overview of possible applications in accordance with the alloy and polarity is contained in Table 1.
The disadvantages of a punched grid. The disadvantages of a punched grid distinctly outweigh the productivity benefits. Practical experience in commercial vehicles has shown the considerable problems derived from this technology and therefore leading OEMs do not employ it without question. Owing to its use of a lead-calcium alloy, the punched grid is subject to general disadvantages related to chargeability and cyclical resistance. In addition the gassing voltage in the Ca alloy is much higher, which in many cases results in premature battery failure owing to acid stratification and a subsequent charge shortage. In particular, this is evident in vehicles with a large number of electrical consumers on board and cyclical loads. Consequently, following a deep discharge, the battery can never be properly recharged to a complete extent. In addition, a punched grid is relatively thin and therefore subject to warping (plate curvature). Even minimum, excessive pasting on one side can lead to serious plate warping with the result that both the separator and the active mass are damaged irreparably. In a worst-case scenario this leads to early battery failure caused by a short circuit. What makes Banner so successful? Banner can turn to over 75 years of experience and know-how and as the quality leader quickly recognised and solved this problem.
Banner GmbH, A-4021 Linz, Austria, Postfach 777, Banner Strasse 1, Tel. +43/(0)732/38 88-0, Telefax Verkauf +43/(0)732/38 88-21599, E-mail: office@bannerbatterien.com Author: Thomas Langthaler, Marketing
Banner relies deliberately on cast positive grid (book casting) and hybrid design in which the positive plate is formed from a lead-antimony alloy and the negative plate from a lead-calcium alloy. The advantages of hybrid technology are clearly evident, as the combination created in this well-proven process provides excellent mechanical characteristics, high levels of cycle resistance, limited water consumption and easy charging. All of which have made Banner a benchmark. Banner is the quality leader. All the latest external battery tests have provided impressive evidence of the leadership enjoyed by Banner batteries, e.g. the Stiftung Warentest 2012 (Power Bull P7209 “Very good”) and Testfakta Sweden 2013 (victory for the Power Bull PRO P6340). Therefore, leading commercial vehicle manufacturers rely on Banner batteries. OEMs such as Daimler, Caterpillar, Liebherr, Kässbohrer, etc. have long relied on Banner’s quality and expertise.