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Technical
Issue
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Major
Battery Chemistry
Lead acid batteries have
low energy density and pose significant environmental
problems. They are the oldest chemistry and are
on its decline.
Nickel (NiCd) batteries do not have enough
energy density for the latest portable electronics
and communication devices. The environmental problems
associated with NiCd batteries are also significant,
and disposal is highly regulated in most countries.
Nickel-metal hydride (NIMH) batteries, while
superior to NiCd in a number of areas, also with
a limited energy density, are relatively heavy,
and pose serious environmental concerns. They suffer
from a high self-discharge rate and limited cycle
life. (Number of charges)
Liquid Lithium-ion (LLI) uses a lithiated
cobalt oxide cathode and liquid electrolyte. This
system offers high energy density, longer cycle
life and a lower discharge rate. However, cobalt
is expensive and toxic in a way that it may release
oxygen under certain conditions. In addition, to
contain the liquid electrolyte, LLI cells must have
a rigid metal housing, which adds considerably weight
to multiple-cell packs. The liquid electrolyte is
flammable; is a cell's internal pressure is increased
(under abuse conditions); the cell may release some
of its liquid electrolyte and could cause a fire.
Lithium Polymer batteries use a Lithium metal
anode and a solid polymer electrolyte, but are plagued
by safety issues related to Lithium metal and has
low cycle life (usually less than 30)
Polymer Lithium-ion battery -the most advance
technology development, pioneered by Bell Communications
Research ("Bellcore"). PLI batteries offer
better safety, longer cycle of life, better energy
density and much more flexible cell design and configuration
compared to NiMH or LLI technologies.
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Product
Development
With our advanced aluminum
foil packaging technology and our duplex cells of
about 1 mm thickness, we can now offer greater flexibility
in cell sizes and shapes. Our cells can have any rectangular
dimensions to suit specific application, while thickness
can also vary from 2mm to 10mm or more. (Please
click to view size and shaping efficiency diagram)
In order to speed up product development, we work closely
with various electronics IC providers and a leading European
design firm specializing in charging technology. As a
result, we can provide: -
(i) Pack monitoring and balancing circuits:
Whenever the appliance require two or more cells in
series (cellular phone or laptop computer), we have
available a very compact control unit which provides
cell balancing as well as cell protection (over/under
voltage, over current) for increased performance. We
design very impact fast charge circuits adapted to particular
PLI battery. Our charging circuit provides a 90% charge
within the first hour. (Click
to view discharge characteristics graph) We can
also integrate this circuit into a charger / cradle
designed for a particular device.
(ii) Smart Battery System:
We can develop complete smart battery and smart charger
solutions complying with SMBus, Smart Battery Data specifications.
According to our experience and laboratory expertise,
we have completed prototyping and validation of new
cell or complete power solution. An initial prototype
of replacement Li-ion batteries and demonstration units
for new laptop and cellular phone batteries has become
available since the end of year 1998.
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