Effects of AB5-type hydrogen storage alloy prepared by different techniques on the properties of MH/Ni batteries

The effects of hydrogen storage alloy prepared by different preparation techniques with composition Mm(NiCoMnAl)5 on the properties of MH/Ni batteries have been investigated. Compared with as-cast alloy, as-quenched and as-quenched+annealed alloy could produce advantages to the battery in high rate dischargeability, internal pressure, cycle lifetime and internal resistance at beginning of cycles. Unfortunately, the rapidly quenched alloy slowed down the initial activation rate of the battery voltage, but after annealing, the rate would improve slightly. The influence of the alloy from different preparation techniques on the capacity and voltage of batteries is slight. The annealing would mainly improve the high rate dischargeability and depress the internal pressure contrasted with the as-quenched alloy. The differences can be ascribed to the change of phase and microstructure caused by different preparation techniques.