May, in Encyclopedia of Electrochemical Power Sources, 2009 Tubular plate cells They are used for telecommunications for standby power in main switching centers in fixed line telephony but are being displaced by sealed gelled electrolyte OPzV cells. Lead–antimony plates provide good cyclic endurance and in areas where the reliability of the public utility is poor or for supporting solar power installations, tubular cells provide good service. A sufficient quantity of electrolyte is provided to extend the watering interval to 3 years and the overall service life is up to 15 years. The specific gravity is higher than that of pasted plate cells. Pillar seals vary in complexity between suppliers but offer freedom from corrosion and leakage over the service life of the battery. Cell containers are molded in SAN so that the electrolyte level and the condition of the cell can be readily seen. The negative plates are of the pasted plate type and generally microporous polyethylene separators are used. A fabric gauntlet is used as the retainer for the positive active material. The positive plates have die-cast low-antimony alloy spines although some suppliers offer Pb–Ca–Sn spines as an alternative ( Figure 2). Tubular plate cells are generally built in conformity with the German Institute for Standardization (Deutsches Institut für Normung, DIN) OPzS specification. This major shift in battery design has brought about a new set of scientific and technological challenges. The drive toward increased convenience through eliminating the need for water maintenance and avoiding the release of acid-carrying gases has led, however, to the widespread adoption of the ‘valve-regulated’ form of the lead–acid battery. With the aid of the above four measures, substantial service lives can be obtained from flooded batteries in their various applications.
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Incomplete Chargingīattery packs operated under PSoC duty (as experienced in RAPS and in EVs) are supported by a management system that periodically calls for full charge in order to maintain capacity (a so-called cell equalizing charge). Acid StratificationĪcid concentration gradients can be removed through agitation of the acid by setting the battery to deliberate gassing during extended overcharge. Water loss can be made good by the process of ‘topping up’. Tubular positive plates have gauntlets, which constrain the active material and reduce its tendency to expand, disconnect, and shed. For the flat design of positive plate, expansion normal to the plate can be moderated by applying a compressive force to the plate group. The use of lead−antimony alloy enhances the creep strength of the positive grid and thus retards growth in the plane of the plate. Most of the above modes of failure can be suppressed to an acceptable level in conventional lead–acid batteries, as follows. Moseley, in Encyclopedia of Electrochemical Power Sources, 2009 Traditional Remedies for Failure Thus, sealed and maintenance-free batteries do not use lead–antimony alloys.ĭ.A.J. Batteries using lead–antimony alloy grids generally must have periodic water additions. The effects are accelerated at elevated temperatures. This gassing phenomenon causes a general water loss in the batteries. There it modifies the plate potential during charging to promote the breakdown of the water in the electrolyte and the generation of hydrogen. In positive grids containing lead–antimony, some of the antimony is released from the corrosion product of the grid, dissolved in the electrolyte, and transferred to the negative plate.
Lead–antimony alloys are 3–10% less conductive than comparable calcium or tin alloys, and reduce battery performance.ĭuring battery operations, the positive grid is oxidized.
Thin grids require alloys of the highest conductivity for optimum performance. Antimony added for mechanical properties increases the electrical resistance of the alloys and subsequently the grids produced from them. Rolled lead–antimony alloys have such low mechanical properties due to breakup of the cast-in second-phase particles that this material is not used in continuous grid production.ĭespite the benefits of antimony as an alloying element for battery grids, modern vehicle requirements have led to significant reductions in the use of lead–antimony alloys for starting, lighting, and ignition batteries. Modified alloys can be continuously cast into strip that is subsequently expanded or punched to form grids. Magnification 160×.īecause low antimony alloys contain small amounts of second-phase material, and are relatively fluid, they have also been used for long-spined tubular battery grids and can be continuously cast into grids. The grain structure of a lead–antimony alloy (1.6% Sb) shows small amount of eutectic and rounded structure due to selenium nucleant.
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