It is a rechargeable battery type. They are in use since the late 1980s. Due to their steady increase in performance, they prove excellent for small, lightweight, portable, and handheld applications.
Some the features of NiMH are:
Its energy density is higher when compared to other types but at the expense of reduced cycle life.
There are no toxic metals, and
Less prone to memory effect than NiCd.
The cylindrical nickel-metal-hydride used for commercial purpose gives a mid-range energy density of around 80Wh/kg and delivers roughly 400 cycles. The prismatic nickel-metal-hydride is a battery that is made for slim geometry, compromises on energy density and cycle count. It is rated at a moderate 60Wh/kg and offers around 300 cycles. Highly durable nickel-metal-hydride for industrial use are packaged in cylindrical cells, provide a modest 70Wh/kg but last for about 1000 cycles.
