What are the effects of overcharge and overdischarge on battery performance? Posted by benzoenergy.com
What is overcharging and how does it affect battery performance?
Overcharge
refers to the behavior of continuing to charge the battery after it has
been fully charged in a certain charging process. Since the capacity of
the negative electrode is higher than that of the positive electrode in
the design, the gas from the positive electrode permeates through the
separator paper and recombines with the cadmium from the negative
electrode. Therefore, under normal circumstances, the internal pressure
of the battery will not increase significantly, but if the charging
current is too large, or the charging time is too long, the oxygen that
appears is too late to be consumed, which may cause the internal
pressure to rise, battery deformation, and liquid leakage, and other
undesirable phenomena. At the same time, its electrical performance will
also be significantly reduced.
What is over-discharge and how does it affect battery performance?
Over-discharge
means that the battery has discharged the internally stored power,
after the voltage reaches a certain value, continuing to discharge will
cause over-discharge. The discharge cut-off voltage is usually
determined according to the discharge current. 0.2C-2C discharge is
generally set to 1.0V/branch, and above 3C such as 5C or 10C discharge
is set to 0.8V/branch. Overdischarge of the battery
may bring catastrophic damage to the battery consequences, especially
large current over-discharge, or repeated over-discharge will have a
greater impact on the battery. Generally speaking, over-discharge will
increase the internal pressure of the battery, and the reversibility of
the positive and negative active materials will be destroyed. Even if it
is charged, it can only be partially restored, and the capacity will be
significantly attenuated.
What problems will occur when batteries of different capacities are used in combination?
If
you mix old and new batteries with different capacities, liquid leakage
and zero voltage may occur. This is because during the charging
process, the capacity difference causes some batteries to be overcharged
during charging, and some batteries are not fully charged. During
discharging, some batteries with high capacity are not fully discharged,
and batteries with low capacity are over-discharged. In such a vicious
circle, the battery is damaged and leaks or has a low (zero) voltage.
The lithium battery protection circuit board
has the battery overcharge protection function, overdischarge
protection function, overcurrent protection function, short circuit
protection function, temperature protection function, charge power
balance management function, etc. In order to prevent the battery from
overcharging and over-discharging, the battery generally needs to be
installed with a protection circuit board to protect the stable
performance of the battery.
BENZO Energy Technology Co.,Ltd
UFine Technology Co., Ltd
Site: www.bz-battery.com / www.benzoenergy.com
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