Validation of alternative additives for paste production

Dissertation presented to confer Master Degree in Chemical and Biochemical Engineering

This Dissertation is the result of an internship at the factory of the Group Exide Technologies located in Castanheira do Ribatejo - Portugal, the world leader in Battery Productions. The subject is in context of continuous improvement, reengineering of the process to meet green VRLA - Valve Regulator Lead Acid Battery productions. Initially, a brief description was made about the technology and productions of Lead- Acid Batteries at a normal productions. Then, started the executions of Experimental Productions related to the following case studies: 1. Replacement of expander Vanisperse A by a expander Vanisperse HT-1 used in negative paste. This research was conducted in order to find an alternative additive to replace Vanisperse A and reduce overhead cost. The development of this experimental productions was made by producing negative plates with expander Vanisperse A as normal production and other negative plates with expander Vanisperse HT-1 as an experimental productions considering the concentration of 1.8% , 2.1% and 2.3% being four samples in three types of battery, then performed chemical and electric test of both version for comparison. Conducted performance test, daily discharge, and retention for C10 cycles and C0.25. It was not possible to draw any conclusion since the values does not comply the nominal specifications. 2. Elimination of Boric Acid in GroE dry negative plates to follow the mindset of continuous improvement and reengineering of the process for green productions of GroE Cells due to environment purposes and related to article 33 of REACH. By ECHA - European Chemical Agency norms and legislations boric acid may have restriction in near future regarding the SVHC issues. Therefore to prevent it, Exide Technologies is looking forward to find another alternative additive to be used in impregnations of dry negative plates as an inhibitor of plates oxidations, thus managed to replace it by new additive the ”Baysilone”. In experimental productions for impregnations of plates in GroE Cells following the industrial, electrics tests. The results was outstanding regarding the performance test run on 3 batteries treated with baysilone compared to other 3 batteries treated with boric acid and consequentely, today Castanheira de Ribatejo facilities has altered the process to baysilone additive. 3. Carbon based additives in negatives plates applied in HEV-Hybrid Electric Vehicles. This OPE-Experimental Productions Order was performed along with battery experts from Exide Technologies – USA. Over one hand the pasting for normal productions was done using the facilities, making sure that the plates was meticulously selected with no empty pellets as well as the size. By another hand, the pasting for experimental productions was hand pasted using HSAG-High Surface Area Graphite, Printex, ABG and Sphere by which the plates thickness and weights has been always scrupulously checked before curing.The experimental productions was conducted with several separator in order to define the best outcome that follow the clients specifications. The batteries were sent to investigation laboratory in Exide Technologies – USA as well as to C.L.E.P.C – Central Laboratory of Electrochemical Power and Source at Bulgarian Academy of Science for further tests. The performance test run in Lisbon did not meet our specifications in order to draw any conclusions.