Leady oxide battery performance

This lead compound forms prismatic crystals with a length of 1—4 pm and 0.2—08 pm in cross section. Its density is 6.5 g cm. It is poorly soluble in water, 0.0262 g L. 3BS is obtained when leady oxide is mixed with sulfuric acid solution (up to 8 wt % H2S04/Pb0) and constitutes the basic component of the battery paste when the latter is prepared at temperatures below 70 °C. Tribasic lead sulfate exerts an influence on the structure of the lead dioxide active mass and thus on some of the performance characteristics of the battery. 

In 1898, George V. Barton proposed a method that made the production process of lead oxide considerably faster and easier. This method yields partially oxidized lead powder (leady oxide) which ensures high battery performance. 

Especially important for proper operation of the battery are the impurities contained in the metal used for leady oxide manufacture. Lead for the battery industry is derived from ores mined in different parts of the world (primary lead) or is obtained by recycling of used up batteries that have reached their end of fife (secondary lead). The recycling process is very often performed at the battery manufacturers facilities. Purity standards have been adopted for the lead to be used for leady oxide production. These standards specify different maximum allowable amounts of impurities for flooded and valve-regulated lead-acid battery applications. Table 5.2 presents typical purity specifications for lead for making leady oxide for flooded batteries. 

Influence of Leady Oxide Properties on Battery Performance Characteristics... 

The above investigations indicate that the physical and chemical properties of the lead oxide used as precursor material for the production of battery plates, though the lead oxide is only a starting compound for a number of chemical processes (paste preparation and plate formation, whereby Pb02 and Pb are formed), exert an influence on the energetic and capacity performance parameters of lead-acid cells and batteries. Hence, it is essential to produce leady oxides with optimum and stable physico-chemical properties which would guarantee high battery performance. 

A well-balanced expander formulation, containing the above three components, guarantees good performance of the negative active material, especially at low temperatures. A typical expander formulation used in the battery industry is 0.2—0.3% lignosulfonate, 0.8—1.0% BaS04, 0.1—0.3% carbon black, all calculated in weight percent vs. the leady oxide used for paste preparation. 

The pony mixer is the traditional unit. A preweighed amount of leady oxide is placed into the mixing tub, and this is wetted first with water and then with sulfuric acid solution. Dry paste additives, if any, are premixed into the leady oxide before water addition. These additives can be plastic fibers to enhance the mechanical strength of the dried paste, expanders to maintain negative-plate porosity in operation, and various other proprietary additives which ease processing or are believed to improve battery performance. Muher mixers are usually filled first with the water component, then the oxide, then the acid. 

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