Datasheet

Rechargeable Button Cells
4.3 PROPER USE AND HANDLING
NiMH cells are sealed designs which are maintenance
free. These products may be used in any operating
position. They should be kept clean and dry during
storage and operation. In general, batteries or cells
will be shipped in a partially charged state. Therefore
caution should be exercised not to short-circuit them
at prolonged periods of time. Cells or batteries must be
charged before use to obtain full capacity. Storage is
possible in any state of charge. Storage temperatures
between -20°C and +35°C are recommended at a rela-
tive humidity of approximately 50%. In case of long-term
storage cells and batteries should be recharged mini-
mum once every year. In order to ensure performance
expectations, the following conditions for use and hand-
ling are recommended.
Charging
Charging should be conducted as previously described
in “Charging Methods” (see page 18/30). Extended
charging outside specified temperature ranges may have
an adverse effect on cell life. Also permanent charging
exceeding the limits of specified temperature ranges may
reduce the battery life. The maximum life is achieved,
when charging at an average temperature
of +20 to +30°C.
Discharging
The specified temperature range is from -20 to +60°C
resp. +85°C on discharge. Repeated discharges at the
extreme temperatures may affect battery life. In all
applications do not deep-discharge (< 0.6 V/cell) our
NiMH cells and batteries.
Life Expectancy in Long-term use
Batteries are chemical products involving chemical
reactions. Hence capacity and voltage will decrease
over long time use as well as during long-term storage
capacity and voltage will drop. Typically, a battery will
last 5 years or 1000 IEC cycles, if used under recom-
mended conditions and not overdischarged or over-
charged. However, non-observance of recommended
conditions concerning storage, charging, discharging,
temperature and other factors during use can lead to
shortened life expectancy of products and deterioration
of performance.
Cell reversal
In general, cell reversal should be avoided. If four or
more cells are connected in series, it is necessary that
these cells have matching capacities. The process of
selecting cells of similar capacities is called “matching”.
For multicell configurations a cut off voltage of 1.0 V per
cell or higher should be applied for discharge rates up
to 1 CA. For configurations containing more than 6 cells
in series and/or discharge rates exceeding 1 CA, please
ask us for advice.
Short circuit protection
Because the internal resistance of NiMH cells and
batteries is rather low, a prolonged short circuit will
result in very high currents. This may lead to excessive
heat generation and cell venting. Therefore prolonged
short circuit must be avoided under all circumstances.
The use of Polyswitch in battery configurations is
recommended. Additional protection should be given
to exposed battery terminals.
Severe use applications
Short term use of NiMH batteries outside specified
ranges may be possible. Please consult us, if such a
requirement exists.