Battery maintenance-free

R. D. Prengaman, Adpanced Eead Alloysfor Maintenance-Free Batteries, Lead Development Association, London, UK, 1980. 

Of the elements commonly found in lead alloys, zinc and bismuth aggravate corrosion in most circumstances, while additions of copper, tellurium, antimony, nickel, silver, tin, arsenic and calcium may reduce corrosion resistance only slightly, or even improve it depending on the service conditions. Alloying elements that are of increasing importance are calcium especially in maintenance-free battery alloys and selenium, or sulphur combined with copper as nucleants in low antimony battery alloys. Other elements of interest are indium in anodesaluminium in batteries and selenium in chemical lead as a grain refiner ". 

The hydrogen and oxygen produced create a safety hazard. Beyond that, they can cause Pb, Pb02, and PbS04 to flake off the plates. In a modem maintenance-free battery, the lead plates are alloyed with small amounts of calcium, which inhibits the electrolysis reaction. 

D. Berndt, Maintenance-Free Batteries, Research Studies Press, Taunton, UK John Wiley, New York, 1993, 1st ed., p. 40, 1997, 2nd ed, 102. 

Potential for very high cell and battery reliability (small electrolyte shapes have fewer defects small cells offer maintenance-free batteries by providing a multiplicity of parallel paths) ... 

Bemdt, D. Maintenance Free Batteries, 3rd ed.. Research Studies Press Ltd. Taunton, Somerset, England, 2003. 

Refs. [i] Linden D, Reddy TB (eds) (2001) Handbook of batteries, 3rd edn. McGraw-Hill [ii] BerndtD (ed) (2003) Maintenance-free batteries lead-acid, nickel/cadmium, nickel/hydride - A handbook of battery technology (Electronic electrical engineering research studies power sources technology). Research Studies Press... 

Maintenance-free battery— A rechargeable - battery that does not require replenishing of water during its service life. Usually the term refers to maintenance-free -> lead-acid and sealed nickel-cadmium batteries, which, in contrary to the conventional ones, are designed to suppress water loss due to -> electrolysis (overcharging) and evaporation. 

D. Berndt, Maintenance-Free Batteries, Research Studies Press, Taunton, UK, 1997. 

A specialized field of operation for maintenance-free batteries is military applications. Many vehicles are used very infrequently but should still be operable on short notice. Within European armies, a significant number of gel VRLA batteries are in use. 

To complicate the situation even more, many of the properties of an AGM battery are already exhibited by modern, totally maintenance-free batteries with liquid electrolytes. This is particularly true for starter batteries as they are only expected to have a service-life of about 2000 h, which is considerably less than one-tenth of that which industrial battery manufacturers claim their products achieve when used in constant-voltage, float-charging applications. As a result, a VRLA battery will be used in vehicles with conventional electric power systems only if its advantages over a flooded battery are really needed. These include the following. 

D. Berndt, Maintenance-free Batteries, John Wiley Sons, New York, 2nd Edition, 1997. 

These are small, maintenance-free batteries which are sealed as the electrolyte is not depleted during operation. The electrolyte is absorbed in a porous separator or in a get, so that the battery can be operated in different orientations without spilling. This allows the batteries to be used in portable devices. 

Maintenance-free batteries (with PbCaSn or low Sb, As and Sn for the positive plates and PbCa grids for the negative plates). 

In order to minimise, or even eliminate, the need for maintenance, the battery should operate with minimum water loss. This is achieved when the over-voltage of hydrogen and oxygen evolution on Ph and Pb02 surfaces, respectively, is very high. This is of utmost importance for VRLA and maintenance-free batteries. Hence, it is essential to reduce the rate of hydrogen evolution at the negative plates and to find appropriate methods to oxidize the evolved... 

Battery-manufacturing practice has limited calcium concentration in the Pb—Ca alloys used in the battery industry to between 0.05 and 0.06 wt%. Plates with grids produced from such alloys cause negligible gassing and are suitable for application in maintenance-free batteries. However, fliese alloys are susceptible to the PCL effect. Appropriate additives are looked for in order to suppress this effect of Pb—Ca alloys when used for the positive battery grids. A survey of fliese additives will be made further in this chapter. 

D. Berndt, in N.E. Bagshaw (Ed.), Maintenance-free batteries. Research Studies Press Ltd., John Wiley Sons, New York, USA, 1993, p. 57. 

Comprehensive investigations in this direction are of utmost importance, especially for maintenance-free batteries. The inhibiting effect should be studied in correlation with the effects of expanders as both substances are adsorbed on the lead surface and may mutually facilitate or impede their influence. 

This chapter made an overview of the main techniques employed to suppress the effect of the side reactions of water decomposition through catalytic recombination of H2 and O2 to water (catalytic plugs) or through operation of a COC (VRLAB). These methods have reduced, or even eliminated, the need for battery maintenance, as a result of which maintenance-free batteries are gaining ever increasing share of the battery production nowadays. 

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