The positive active material of
NiMH-NiCD Battery is mainly made of nickel, and the negative active material is mainly made of hydrogen storage alloy.
NiMH is an improvement from a NiCd battery, which replaces cadmium (Cd) with a metal that can absorb hydrogen. It provides higher capacity, less obvious memory effect, and lower environmental pollution (without toxic cadmium) than nickel-cadmium batteries at the same price. Its recycling efficiency is better than that of lithium-ion batteries, and it is known as the most environmentally friendly battery. However, when compared with lithium-ion batteries, it has a relatively high memory effect. The old nickel-metal hydride battery has a high self-discharge response, and the new nickel-metal hydride battery has a fairly low self-discharge (similar to alkaline electricity), and can work at low temperature (-20 ℃).
Nickel-metal hydride batteries have a larger output current than carbon-zinc or alkaline batteries, and are relatively more suitable for high-power consumption products, and some special models even have a larger output current than nickel-cadmium batteries.
NiMH-NiCD Battery Features:
Voltage = 1.2V
Energy/Weight = 60-120 Wh/kg (Wh/kg)
Energy/Volume = 140-300 Wh/L (watt hours/liter) or 504-1188kJ/kg (kilojoules/kg)
Self-discharge rate = typically 2-30% per month, depending on temperature, 10-30% per year for low self-discharge models
Charge and discharge efficiency = 66%
Number of charge and discharge cycles = 500 -1800 times
