Lead Acid Battery Plates Research Articles

Thermopassivation of the Lead Dioxide Plate of Lead Acid Batteries

After formation, the positive plates of lead acid batteries are washed and dried. When they are dried at temperatures above 70°C in a drying chamber oven they lose part of their energy. In this paper this phenomenon is called thermopassivation. The thermopassivation is measured by the difference between the galvanostatic discharge potential curves of the thermopassivated and unpassivated plates. The dependences of thermopassivation on the temperature of drying, hold time of the plates in solution, current density, pretreatment of thermopassivated plates in solution, and the number of charge‐discharge cycles are determined. It is concluded that the thermopassivation may be due to the semiconductor properties of the nonstoichiometric corrosion layer of the plate and its contact with the crystals of the active mass, as well as the contact of the active mass with the solution in the pores.

The impedance of a lead acid battery negative plate

An attempt is made to interpret the impedance, measured near to E°, of various negative lead acid battery plates in H 2SO 4.

Pore Volumes and Densities of Unformed Pastes of Lead Acid Battery Plates: II: Tetrabasic Lead Sulfate Pastes

The values of specific pore volume, , and the solids' density, , were determined for unformed lead‐acid battery pastes prepared from . varied with , the apparent density of the dry paste according to . The parameters and were related by . By that relationship, however, is variant with , an unexpected result. It is proposed that the variance results because the crystals of tend to orient in tight bundles, especially for the pastes with the highest values of . Such bundles entrap open pits on the crystal surfaces, and the measured values of are then reduced.

The elementary physicochemical processes during the first stage of formation of the negative lead-acid battery plate

The elementary physicochemical processes during the first stage of formation of the negative lead-acid battery plate

The elementary physicochemical processes during the first stage of formation of the negative lead-acid battery plate

During the first formation stage of the negative plate in H 2SO 4 solution lead monoxide and tribasic sulphate transform into Pb and PbSO 4 giving rise to a Pb−PbSO 4 zone. It was established that these processes take place within a thin layer (the δ-layer) situated between the Pb−PbSO 4 zone and the paste. The rate determining step is the transport (by diffusion and migration) of H + and SO 4 2− ions from the bulk of the electrolyte towards the δ-layer. An equation is derived for the dependence of the concentration of the H 2SO 4 in the Pb−PbSO 4 zone on the thickness of this zone. It was found that during formation until a limiting thickness of the Pb−PbSO 4 zone, PbSO 4 originates mainly at the expense of the H 2SO 4 present in the bulk of the electrolyte. When the formation rate of PbSO 4 becomes very small the reaction of PbSO 4 reduction to Pb takes place. This reaction proceeds in a second reaction layer (the α-layer) which is located in the Pb−PbSO 4 zone at the plate surface. Subsequently, the formation of PbSO 4 in the δ-layer takes place at the expense of H 2SO 4 generated in the α-layer. The model is confirmed by the experimentally determined distribution of PbSO 4 across the cross-section of the plate during formation.

The effect of temperature and current density on the capacity of lead-acid battery plates

The discharge characteristics of positive and negative plates of the lead-acid cell have been determined at various cds and temperatures. The effective plate capacity C at θ°C is related to the current density I by the equation ▪ where n = 1·4 for both types of plate. Values of the constant K 0 and the temperature coefficient α differ for the two electrodes.

Microscopic examination of active materials from lead-acid cells

Sections of lead-acid battery plates in various states of formation, charge and discharge have been examined microscopically. The formation of both the positive and negative plates begins at the grid/active-material interface. The discharge of both plates begins on the surface and penetrates into the bulk of the active material. The utilisation of the active material is illustrated. α and β lead dioxide can be differentiated by their colours under the microscope by the use of an oil-immersion lens. The residual lead in the pasted positive plate is always converted to the α form. β lead dioxide is more easily discharged than the α modification but the latter holds the plate together and is necessary for a long cycle life.

The discharge characteristics of lead-acid battery plates

An apparatus was developed whereby a single battery plate could be discharged at high rates out of the environment of the accumulator. During the discharge the transient potential of the plate was measured continuously to an accuracy of 0·01 V. The results showed that the capacity of a plate was related exponentially to the current density of discharge. The discharge characteristics are discussed in terms of activation and concentration overpotentials.

Determination of lead sulfate by means of cation exchangers

A method for the determination of lead sulfate is described using the following procedure: The lead sulfate is boiled in a solution of sodium carbonate ; after cooling, the solution is saturated with carbon dioxide and the precipitated lead carbonate is filtered off. The filtrate is boiled with a strongly acid cation exchanger in the hydrogen form and after cooling, the solution and resin are poured into an ion exchange column, containing a short layer of resin. After washing with ater the combined filtrate and wash water is titrated with 0.1 N sodium hydroxide using phenolphthalein as indicator. The method is accurate and gives a maximum relative error of ± 0.4%. The procedure described above has been used for determination of the degree of sulfation in lead-acid battery plates.

Addition Agents for Negative Plates of Lead-Acid Storage Batteries

Addition Agents for Negative Plates of Lead-Acid Storage Batteries