Improving the electrical performance of lead acid battery with electrodes containing different additives

Enhanced flooded battey (EFB) is used on start stop vehicle that is serially producted because of sanctions for reducing emission values by European Union. These batteries have positive & negative paste containing different additives. Within the scope of the thesis, it is aimed to increase the electrical performance of EFB batteries by improving chemical properties of negative and positive electrode. For this purpose, H2O2, diatomites, carbon black and carbon fiber were used as additives in positive and negative paste. Experimental studies consist of three parts. In the first part, these additives and other chemicals (PbO, sulfuric acid, lignosulfonate, barium sulfate, glass fiber) were characterized. In the second part, positive and negative electrodes (anode, cathode) was prepared and characterized. The last part, prototype batteries or cells was prepared and electrical performance tests were done. Consequently, increasing the porosity of electrodes and penetration of sulfuric acid into more surface area were aimed adding diatomite additive in the positive and negative active material. However, diatomite has adversely affected the charge efficiency because of it creates passive areas in the active material. Carbon fiber additive were used in the positive and negative active material both in order to hold of the paste and bring carbon black properties. But, electrical performance of the batteries was not increased since carbon fiber was not homogenously distributed in the negative active material. Carbon black was added mixed with water and sulfuric acid for homogenously distrubition in the negative active material. With this additional method has positively contributed battery electrical performance. H2O2 additive was used both positive and negative active material in order to prevent excessive temperature rising, keep high moisture, increase porosity of electrodes by forming an intermediate reaction with free lead. Electrical performance of batteries is significantly increased with high porosity electrodes.