Ni-MH batteries are divided into high-voltage nickel-hydrogen batteries and low-voltage nickel-hydrogen batteries.

　　Low-voltage nickel-metal hydride batteries have the following characteristics: (1) The battery voltage is 1.2~1.3V, which is equivalent to nickel-cadmium batteries; (2) The energy density is high, which is more than 1.5 times that of nickel-cadmium batteries; (3) Quick charge and discharge, low temperature Good performance; (4) It can be sealed and has strong resistance to overcharge and discharge; (5) No dendrites are formed, which can prevent short circuits in the battery; (6) Safe and reliable, no pollution to the environment, no memory effect, etc.

　　High-voltage Ni-MH batteries have the following characteristics: (1) High reliability. It has better over-discharge and over-charge protection, can withstand higher charge-discharge rates and has no dendrite formation. Has good specific characteristics. Its mass specific capacity is 60A·h/kg, which is 5 times that of nickel-cadmium batteries. (2) Long cycle life, up to thousands of times. (3) Compared with nickel-cadmium batteries, it is fully sealed and less maintenance. (4) Excellent low temperature performance, the capacity does not change significantly at -10°C.

　　Pay attention to maintenance when using Ni-MH batteries.

　　(1) Avoid overcharging during use. During the cycle life, avoid overcharging during use. This is because overcharging easily causes the positive and negative electrodes to expand, causing the active material to fall off, the diaphragm is damaged, the conductive network is damaged, and the ohmic polarization of the battery becomes larger.

　　(2) Prevent the deterioration of electrolyte. During the cycle life of Ni-MH batteries, hydrogen evolution should be suppressed.

　　(3) Storage of Ni-MH batteries. The storage of Ni-MH batteries should be fully charged. If the battery is stored for a long time without storing electric energy in the battery, the function of the battery's negative hydrogen storage alloy will be weakened and the battery life will be shortened.