Numerical model lead-acid accumulator grids

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angličtina

The lead-acid battery uses lead dioxide as the active material of the positive electrode and metallic lead, in a high-surface-area porous structure, as the negative active material. Typically, a charged positive electrode contains both a-PbO2 (orthorhombic) and a-PbO2 (tetragonal). The equilibrium potential of the a-PbO2 is more positive than that of a-PbO2 by 0,01 V The á form also has a larger, more compact crystal morphology which is less active electrochemically and slightly lower in capacity per unit weight; it does, however, promote longer cycle life. Neither of the two forms is fully stoichiometric. Their composition can be represented by PbOx, with x varying between 1,85 and 2,05. The introduction of antimony, even at low concentrations, in the preparation or cycling of these species leads to a considerable increase in their performance. The preparation of the active material precursor consists of a series of mixing and curing operations using leady lead oxide (PbO + Pb), sulfuric acid, and water. The ratios of the reactants and curing conditions (temperature, humidity, and time) affect the development of crystallinity and pore structure. The cured plate consists of lead sulfate, lead oxide, and some residual lead (<5%). The positive active material, which is formed electrochemically from the cured plate, is a major factor influencing the performance and life of the lead-acid battery. In general the negative, or lead, electrode controls cold-temperature performance (such as engine starting). The electrolyte is a sulfuric acid solution, typically about 1,28 specific gravity or 37% acid by weight in a fully charged condition.

lead acid accumulator grids, numerical modeling, grids

FIALA, P.; ROUBAL, Z.; SZABÓ, Z.

2009

30. 8. 2009

Akademické centrum GEPARD International

Brno

978-80-214-3943-6

10 th ABAF Brno 2009 Advanced Batteries, Accumulators and Fuel Cells

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