Study On The Positive Electrode Of MH-Ni Batteries

MH-Ni batteries are developed in recent years. The characteristics ofthe positive electrode determine the properties of MH-Ni batteriesbecause MH-Ni batteries are limited by the positive electrode. MH-Nibatteries are becoming mature in China, however there is great differencethan those of developed countries, especially in Ni electrode. So studyingon the positive electrode is very important. Three ways were investigatedto improve the characteristics of positive electrode in this paper. The pressing density of positive electrode can affect thecharacteristics of positive electrode. The pressing density of positiveelectrode affecting the characteristics of MH-Ni batteries is investigatedin this paper and the best pressing density is found. Nowadays, EV batteries are the orientation of MH-Ni batteries. Hightemperature charge and discharge of EV MH-Ni batteries are a difficultproblem. Adding Y2O3 in positive electrode and adding Y in lattice ofNi(OH)2 are invested in this paper, and the reaction mechanism is studied.The results show that Adding Y2O3 in positive electrode and adding Y inlattice of Ni(OH)2 can improve charge efficiency at high temperature,then improve high temperature characteristics of MH-Ni batteries. Ni(OH)2 is P type of semiconductor and conductivity is bad. Co isnecessary in MH-Ni batteries. Traditional doping ways are mainly addingCo, CoO or Co(OH)2 in positive electrode. In China most factories addCoO. However this way can not achieve ideal results. Ni(OH)2 of highconducting electricity is produced in this paper. Coating Co(OH)2 andCoOOH can improve conducting electricity of positive electrode. In orderto practically produce in factories, equipment of middle size is designed.