Lithium
Ion Cell Structure |
Historically,
lead-acid, nickel-cadmium (Ni-Cd), and
nickel-metal hydride (Ni-MH) batteries have been
the conventional choice for small-sized rechargeable
batteries.
In line with the recent
trends toward mobile and cordless electronic equipment,
rechargeable batteries are required to provide higher
energy density to meet the needs of ever smaller
and lighter devices. Moreover, the attention being
focused on protecting the environment has resulted
in demand for products that are environmentally
friendly.
Features
of different cell types
A. High Energy Density
The weight of a lithium ion battery is approximately
one half compared to a nickel-cadmium or nickel-metal
hydride battery of similar capacity. Moreover,
the volume of the lithium ion battery is 40 to
50% smaller than that of a nickel-cadmium and
20 to 30% smaller than that of a nickel-metal
hydride battery.
B. High Voltage
A single lithium ion cell has a voltage of 3.7V
( mean value), which is equal to either three
nickel-cadmium or nickel-metal hydride cells connected
in series.
C. Pollution-free
The lithium ion battery does not contain any polluting
substances such as cadmium, lead, mercury, etc.
D. Non-metal Lithium
The lithium ion battery does not employ any lithium
metal. It is not governed by aircraft transportation
rules relating to carrying lithium batteries in
passenger airplanes.
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E. Long Cycle Life
Under normal conditions, the lithium ion battery
has a life of more than 500 charge/discharge cycles.
F.
No Memory Effect
The lithium ion battery is free from the so-called
memory effect, a phenomenon seen in nickel-cadmium
in which the apparent battery capacity decreases
when shallow charge and discharge cycles are repeated.
G. Fast Charge Capacity
The lithium ion battery can be fully charged in
1 to 2 hours, using a constant-current / constant-voltage
(CC/CV) type dedicated charger with a rated voltage
of 4.2V per cell.
Applications
The rechargeable lithium ion battery shows great
promise as a battery to meet such requirement.
This new battery technology has excellent features,
such as: high energy density, high voltage, good
storage and cycle life characteristics. These
batteries are widely used for 3C applications
such as: Personal Computers, Cellular Phones,
and for personal cordless electronic applications
i.e. Portable CD Players, PDA etc |
