The main factor constraining the size and
portability of ultrabooks
- in fact, of mobile devices in general - is the size of the battery. In
previous years, huge gains have been made in the battery technology sphere -
but what form do those take, and what do they suggest for battery technology in
the future?
Nickel-cadmium
(NiCd) batteries were invented by Waldemar Jungner, a Swedish scientist, way
back in 1899. Since then, they’ve been used as the second most prominent kind
of rechargeable battery in laptops up until the ban on cadmium use by the
European Union in 2004 (cadmium is highly toxic). They’ve been almost entirely
superseded by a slight variation on materials: nickel-metal hydride (NiMH)
batteries.
Using a hydrogen-absorbing alloy for the
negative electrode in place of the toxic cadmium, NiMH batteries have been
around since 1989. They grew to dominate the laptop market throughout the
nineties, and are still widely available today.
Some mobile device manufacturers opt instead for
the more modern - and as yet not fully tapped - Lithium-ion (Li-ion) battery.
Boasting improvements of up to 50% on NiMH battery capacity, Li-ion batteries -
or their mould-able cousins, Lithium-ion polymer batteries - look to be the way
of the future.
Apple have been using Li-ion polymer batteries
for years - sensible, given that they custom-design their notebook interiors -
and current ultrabook manufacturers are looking to follow suit. Battery size
and weight is one burning issue for them, but the ability to custom-shape your
battery is equally important. In a slimline housing, any space is at a premium.
One emergent technology that could - in future
years - threaten to override the growing battery market is that of ultracapacitors. Offering faster charge-up and longer discharge times, higher
energy density and lower weight to boot, ultracapacitors rely on separating
charge across a dielectric. They’re becoming increasingly common in hybrid
motor vehicles, particularly in Japan.
The disadvantage to using ultracapacitors lies in their stored voltage - put simply, they’re pretty dangerous. What is more, the mathematics behind their discharge cycle suggests that their stored energy decreases as the square of their stored voltage - meaning they’re high-voltage right up to the last squeeze of juice. So, they’re a little way off being used in notebook computers (particularly if the current aluminium-shell trend takes off).
So, for now, it seems that ultrabook
manufacturers are going to have to make the move towards lithium-ion polymer
battery technology. However, there’s a downside; that market is super-saturated
with buyers. The battery technology is not easy to make, and it’s not easily
scalable (given that batteries have to be made to custom shapes). At the
moment, a handful of manufacturers control the global supply, and it’s
difficult for anyone else to get a look in. It might be that component scarcity
winds up as the determining factor in the ultrabook world.
Article Author: Louis Miller
Article Author: Louis Miller
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