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Ni-MH Battery Characteristics

Cell Construction
1     Cell cap (+)
2     Gasket
3     Current Collector
4     Cell Can (-)
5     Bottom Insulator Flake                 
6     Safety Vent
7     Top Insulator Flake
8     Separator
9     Anode- Nickel Electrode
10  Cathode- Cadmium Electrode

Major Features
Cost effective, Reliable safety vent system, Long service life, Long shelf life,
Wide temperature range, Excellent permanent charge endurance

Major Applications
Lighting:                        Emergency lighting, Solar light, Flashlight
Toys:                              R/C cars, Racing cars, R/C ships
Communications:       Cordless telephone, Two-way radios
Electric Tools:              Electric Screwdrivers, Auto-mower, Portable vacuum cleaners
Audiovisual Devices:  Camera, MP3/MP4, Remote control, Portable DVD
Other Applications:      Shavers, Access controller, and so on

General Characteristics of Nickel Metal Hydride Batteries
Charge characteristics
During charging, the cell voltage of NiMH batteries increases as charging proceeds. It then decreases slightly in the final stage due to heat generation within the cell, eventually reaching an equilibrium. The cell voltage varies widely according to the ambient temperature.
Standard charge    0.1C for 16 hours
Quick charge      0.3C for 4.0 hours
Fast charge        1C for 1.1 hours with –△V or dT/dt controlled


Discharge characteristics
The operating voltage of NiMH batteries varies slightly depending on the discharge current. It is maintained at approximately 1.2V for above 80% of the discharge period.
Standard series cells can withstand a high rate discharge up to 3C. 


Cycle characteristics
Under normal usage conditions, NiMH batteries can withstand over 500 charge/discharge cycles according to IEC criterion. Even under 1C charge/discharge conditions in the accelerating cycle procedure, it can also be expected to provide more than 300 charge/discharge cycles.


Temperature characteristics
NiMH batteries can be used over a vide temperature range. As cell characteristics vary slightly depending on the temperature, in order to obtain optimum performance, the cell should be handled within the specified temperature.
Standard charge      0~40℃
Fast charge         10~30℃
Discharge          -20~50℃


Storage characteristics
With NiMH batteries, self-discharge accelerates as the temperature increase. However the cell capacity decreased through discharging during storage can be restored to its original level by recharging. But in order to minimize the deterioration in battery performance, the cells should be stored at -20~30℃(for long periods).