Ni-MH batteries are an early substitute for Ni-Cd batteries. The toxic cadmium is no longer used, which can eliminate environmental pollution caused by heavy metal elements.
Ni-MH battery uses nickel oxide as the anode and hydrogen-absorbing metal alloy as the cathode. Because this alloy can absorb up to 100 times its own volume of hydrogen, the storage capacity is extremely strong.
The energy density of Ni-MH battery is greater than that of Ni-Cd battery, and its capacity is approximately several times that of Ni-Cd battery;
in addition, it has the same 1.2V voltage as the Ni-Cd battery and self-discharge characteristics. It can be recharged within one hour and has low internal resistance. Generally, it can carry out more than 500 charge and discharge cycles.
Ni-MH batteries have a large energy density ratio, which means that the use of Ni-Mh batteries can effectively extend the working time of the equipment without adding extra weight to the digital equipment.
At the same time, Ni-MH batteries are basically similar Ni-Cd batteries in terms of electrical characteristics, and can completely replace Ni-Cd batteries in practical applications without any modification to the equipment.
Another advantage of Ni-MH batteries is: greatly reducing the "memory effect" existing in Ni-Cd batteries, which makes Ni-MH batteries more convenient to use.

Main features of Ni-MH battery:
Environmental protection: no toxic elements such as cadmium, mercury, lead, etc.
No memory effect
Low internal resistance
Long life: under normal use, the battery can be used for 500-1000 charge and discharge cycles
Low self-discharge performance: after one month of storage at room temperature, the capacity retention rate is above 80%
High discharge platform: under 1.0C discharge conditions, the discharge voltage is greater than 1.2V for up to 40-50 minutes
Good high-rage charge and discharge performance: the battery can be quickly charged within 1-2 hours, and can be used under discharge conditions up to 10-20 rates
Reliable safety valve: after 100% testing, when the internal pressure of the battery is greater than 25atm, the safety valve can be opened automatically
Wide range of temperature adaptability: can be used in the environment of -20℃—50℃

Main application:
Communication equipment: cordless phone, mobile phones, walkie-talkies
Household products: electric shaver, electric toothbrush, massager, portable vacuum cleaner, electric bicycle
Remote control toys: toy racing car, model airplane
Digital products: camcorders, walkmans, global positioning systems, wireless game consoles
Power tools: electric drill, electric saw, sander
Emergency lights and safety systems: smoke alarms, gas detectors, baby monitors
Other applications: solar light

Ni-MH batteries have the following characteristics:
1- The battery voltage is 1.2~1.3V, which is equivalent to Ni-Cd batteries
2- High energy density, more than 1.5 times that of cadmium nickel batteries
3- Fast charge and discharge, good low temperature performance
4- Sealable, 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.

Attentions 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 ohm polarization of the battery becomes larger.
2- Prevent electrolyte deterioration. 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.