Estudo de fatores que influenciam na macroporosidade de placas de baterias chumbo-ácido

• Autor(a) principal: Carvalho, Cynthia Mayara de
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/11043
• topic: Lead-acid batteries; Precursor material; Positive active material; Macroporosity; Porosity; Baterias chumbo-ácido; Material precursor; Material ativo positivo; Macroporosidade; Engenharia Química; Baterias; Porosidade; 66.0

The current global scenario of climate change requires the search for alternative energy sources and it is within this context that lead-acid batteries are, which have many advantages such as ease of manufacture, collection and recycling, low cost and good performance compared to other types of batteries. Due to the mentioned advantages, the lead-acid batteries will remain, for a long time, in the market. A leadacid battery owes its good performance also to the average pore size and the total porosity of its pasted plates. It is essential, for the purpose of control, that there be systematized studies of the influences that act on macropores and how they act, since these macropores are responsible for the mass transfer in the porous system of the plates of a lead-acid battery, besides making part of the charge and discharge reactions in these batteries. The objective of the present study is the understanding of how two factors affect macroporosity: Water quantity and soaking time. For this purpose, mini-plates of lead-acid batteries with variations in the water content added to the paste (made with PbO and water) from 8% up to 15% in mass fraction and miniplates that passed by soaking with time variations of 1h, 2h, 4h and 8h were prepared. The miniplates were characterized by macroporosity tests through the absorption of water to analyze the total porosity; X-Ray Diffraction (XRD) for analysis of crystalline phases; Scanning Electron Microscopy (SEM) for analysis of the morphologies and Brunauer, Emmett, Teller (BET) method for surface area analysis. The results showed an increasing and quadratic relationship between macroporosity and water quantity in the precursor and active positive materials and a decreasing and quadratic relationship between soaking time and macroporosity for the precursor material. For the BET surface area an increasing and quadratic relationship was found with the amount of water and macroporosity for the precursor material. For the positive active material the relation was decreasing and quadratic.