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How
long can a cell be stored?
On theory energy loss can¡¯t be avoided
during store. Its proper electrochemistry
construction makes the losing unavoidable.
Self-discharge is the best-known causation.
Generally this has to do with the electrolytic
solubility of the positive electrode material
or its thermodynamic instability (easy spontaneous
decomposition). Self-discharge in rechargeable
batteries is particularly high in comparison
to primary battery. Furthermore every month
a battery self-discharge rate is various
depending on the system. It changes in the
range of 10-35%. Primary battery self-discharge
is lower considerably. At room temperature
it may even be below 2%. However, various
processes take place in parallel with this
which lead to an increase of the battery¡¯s
internal resistance during storage. These
processes lead to a reduction in load capability.
However energy loss is more noticeable at
relatively high discharge current. The below
table lists self-discharge approximation
under normal storage conditions: type Self-discharge
Alkali manganese£¨MnO2/Zn£©£¬cycloidal £¼2%
Zinc carbon£¨MnO2/Zn£©£¬cycloidal £¼4% Li-ion(LiMnO2)£¬cycloidal
and button cell Approx 1% Ni-MH/Ni-Cd cell
£¼35%
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