Avaliação do efeito da temperatura sobre a corrosão e evolução de gases em grades de baterias chumbo-ácido produzidas a partir de diferentes velocidades de laminação

Abstract

Despite significant improvements in lead-acid batteries over the last few decades, problems such as corrosion and off-gassing persist. Few studies address these phenomena in lead alloy grids formed by rolling. Furthermore, most research focuses on corrosion and off-gassing at room temperature, but actual battery thermal fluctuations are neglected. This study seeks to evaluate how temperature affects corrosion and gas release potentials (HER and OER) in lead-acid battery grids produced with different rolling speeds. For this, grids were produced at three diferente rolling speeds and the tests were performed at three different temperatures for the electrolyte. To evaluate the evolution of gases, the technique of linear scanning voltammetry (LSV) was used. The electrochemical techniques of resistance to linear polarization and corrosimetry sought to evaluate the corrosion in the grids and the cyclic voltammetry and electrochemical impedance were indispensable tools to elucidate mechanisms, action, effects and influence of the temperature and the lamination speed of the lead alloy on the evolution of gases and corrosion of laminated grids of industrially produced lead-acid batteries. The results showed that the gas evolution rate increases both with temperature as well as with the increase in the forming speed of the rolled lead alloy due to the increase in the active sites density on the electrode surface with the increase in the rolling speed of the metallic alloy. Similarly, an increase in the corrosion rate was observed with temperature, and a greater susceptibility to corrosion of the alloy rolled more quickly, due to its less uniform surface and the consequent difficulty in establishing a protective passive layer efficiently and effectively. in a shorter time when compared to those samples produced at lower lamination speeds. During potential scanning in cyclic voltammetry, several lead oxides and sulfates were identified, representing components of the passive protective layer that forms on the surface of lead alloy. The presence of these chemical species was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD).