Discharging - Varta CoinPower CP 1654 A4 Technical Handbook

COINPOWER | CHARGING AND DISCHARGING

3.2 Discharging

Thanks to its coiled electrode design the CoinPower
series can handle very high discharge currents without
any damage or reduction in cycle life while operating
with a very low voltage drop. The cell can be discharged
at 2C continuous and 3C in pulse mode for 2 s. This
makes it possible to run power-hungry devices and to
support even high pulse load profiles. The supported
discharge current can be even higher than 3C for shorter
durations than 2 s.
Discharge Temperature
The cell should be discharged within a temperature
range between -20 º C and 60 º C.
Over-Discharging
If not used for a long time, the cell(s) might become
over-discharged. In order to prevent over-discharging,
the cell(s) should be charged periodically to maintain
a voltage in the range of 3.0 V to 3.8 V.
Over-discharging may cause some loss of cell
performance or impair battery function. The host
product should be equipped with a device which
prevents further discharging below the cut-off voltage
specified in the data sheet.
Important: The PCM over-discharge detection
threshold / v oltage must not be used as the cut-off
voltage for the battery.
Also the charger shall be equipped with a device to
control the recharging procedure as follows:
In case of over-discharging, the cell(s) should be
charged with a low current (0.01 – 0 .07 C) for 15 – 3 0
minutes, i.e. pre-charging, before standard charging
starts. Charging according to the data sheet should be
started after the individual cell voltage has risen above
about 3.0 V and within 15 – 3 0 minutes. This timing can be
controlled by the use of an appropriate timer for pre-
charging.
If the individual cell voltage does not rise to about
3.0 V within the pre-charging time, the charger should be
able to stop charging and display a notification that the
cell(s) is / a re in an abnormal state. In case the individual
cell voltage falls below 2.0 V PCM shall have functions
to disconnect the cell(s) from electronic circuit and cell
shall not be recharged in any case.
Discharging Performance
The graphs below show the discharge curves of all three
cell sizes of the CoinPower series at various currents
(C-rates) and temperatures. The discharge capacity can
be determined when the colored lines reach the 3.0 V
level (End-of-Discharge Voltage). In every header there
is detailed information about the discharge procedure.
The second graph in each example shows the discharge
performance at a 0.2C-Rate at various temperatures
(-20 ° C to +60 ° C).
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