Phenomena That Limit the Capacity of the Positive Lead Acid Battery Plates

Abstract

This paper is the second part of an investigation whose purpose is to establish the mechanism of the processes that proceed during discharge and cycling of the lead dioxide plate of the lead acid battery (LAB). On the basis of this mechanism some electrical parameters that can show the state-of-charge (SOC) and state-of-health (SOH) have to be distinguished. In the first part of this study the shape of the charge potential transient was examined. In this part the electrochemical impedance spectra of a model lead dioxide electrode was investigated in charged and discharged states as well as the changes in impedance spectra during cycling of the electrode with high and low charge currents. It was established that during cycling the values of charge-transfer resistance false(Rnormalctfalse), ion diffusion resistance false(Rnormaldifffalse) in the reaction layer, resistance of the grid/PAM interface false(Rnormalifalse), and ohmic resistance of the electrode false(RnormalΩfalse) change smoothly at first with cycling and after a critical number of cycles have been reached, they start to increase fast. This shows that the electrode is close to the end of its life. The above parameters can be used for the determination of SOH of the positive LAB plate. The discharge processes take place on active centers (ACs) in positive active material (PAM) and interface. A model of the structure of ACs as well as a scheme of the elementary reactions proceeding at discharge in the ACs is proposed. During cycling when the number of ACs in PAM decreases and this one in the interface increases, the capacity of the electrode decreases. On the basis of the changes in the impedance spectra at discharge and charge the changes in equivalent electrical circuit are discussed. © 2002 The Electrochemical Society. All rights reserved.

Studies of the pulse charge of lead-acid batteries for PV applications

“…1a, is very close to the model proposed by Pavlov and Petkova for a completely charged positive plate and used further to fit data from VRLA cells [36,37].…”

On-line measurement of cell impedance during charging and discharging process

“…In this case linear growth of Rct suggests that layer of PbO 2 that forms during process inhibit electrode reaction, making difficult the transport of reagents to surface through the growing oxide layer. Such changes of electric parameters are in agreement with literature regarding relation between resistance and capacitance increase together with SOC [4].…”

“…Oxidation reaction of Pb 2+ to Pb 4+ that take place at that time cause removal of PbSO 4 from the surface and formation of PbO 2 . Process is conditioned by numerous factors, like concentration of electrolyte, value of current or presence additions in electrode material [4,27]. In this case linear growth of Rct suggests that layer of PbO 2 that forms during process inhibit electrode reaction, making difficult the transport of reagents to surface through the growing oxide layer.…”

“…This method, unlike the first one, allows us to examine physicochemical processes in cells. Thus, it is both an excellent tool for modeling the cell's behavior, as well as a diagnostic tool for determining the state of charge (SOC) or the state of health (SOH) [3,4].…”

Energy storage capacity investigation of pulsed current formed nano-structured lead dioxide

“…These properties lead to easier and faster charge transfer through the oxide layer with a short time constant. Additionally, semicircle depression due to porous structure of the oxide layer could be observed and described by a constant phase element, CPE [22]. Fig.…”