The Research Of The High-rate Charge And Discharge Performance Of MH/Ni Battery

The quantity demanded is very huge in vehicle and high power applications, and as the promulgation of the prohibition rule of the production and sale of the Cd/Ni battery, the substitution of the Cd/Ni battery——MH/Ni battery has a very bright prospect on the market. Meanwhile, as the acceleration the pace of the modern city life, the demand of performance of the battery become higher. So, the Rapid Charging battery was born. Generally, the Rapid Charging battery has the character as below: After it is charged in short time with high current, the charging efficiency can reach some specified level. The effect on the performance of high rate charge and discharge of different factor are studied:The CoO,Ni powders and the Na₂WO₄ are studied as addictives in positive electrode. Through the comparison of the performance of inner resistance,high-rate discharge, we obtain a good compounding in positive electrode of MH/Ni battery. The high-rate discharge tests and CV curves shows that Na₂WO₄ as a addictive doping in positive electrode could be useful to increase the performances of the high-rate discharge and the discharge plateau.The physical performances of six kinds of Ni-MH battery separators (3 kinds of fluorizated separators and 3 kinds of sulfonated separators) were comprehensively compared with each other by measuring and calculating their thickness, surface densities, alkaline absorptions, sucking rates, apparent densities, separator porosities and SEM morphologies. With the help of contrasting charge/discharge curves, cycle lives and charge reservation rates, FV3, a special type of sulfonated separator, was selected as the most suitable diaphragm for 15 A, 20 A and 30 A discharge performance of experimental SC3000 Ni-MH batteries with the same positive and negative electrodes. A new method was also proposed for evaluating the effects of separators on high rate discharge performance, which would be valuable to research and develop dynamical Ni-MH battery.A new type of rapid charging AA2000 MH/Ni battery was successfully prepared by using doped agents cobalt-coated Ni(OH)₂, sulfonated separator and KOH+NaOH+LiOH electrolyte. Its 4C charging efficiency could reach 85% without any electrolyte leakage and deformation of steel shell. At the same time, the effect of doped agents in positive electrode,active material, separators and electrolyte on the rapid charging performance were also studied and analysed.Some kinds of process was studied, such as the comparison of dry method and wet method in preparation of positive electrode,different areal density of foaming nickel,gumming of negative electrode. The effect of them to the performance of high rate MH/Ni battery,cycling performance was discussed. Through comparison, it is found that the MH/Ni battery using positive electrode prepared in the wet method,large areal density of foaming nickel,negative electrode gummed in PTFE is better in synthesis performance of high rate MH/Ni battery.