Avionics News March 2015 - 20

batteries for cellphones, notebook computers - and aircraft.
Nonetheless, the Federal Aviation Administration and
other air-safety-regulatory agencies approved some lithiumion batteries for use as the primary aircraft battery - Airbus,
Boeing, Cessna and others - while some battery makers
signaled their faith in the future by breaking with their own
past and eliminating from their production lines old-style
lead-acid batteries.
And despite their known issues, the one thing they seem to
deliver well is a high ratio in power-to-weight-and-volume.

'CELL'-ULAR CHANGES
Continued from page 19

Similar to NiCad and lead-acid before them, lithium-ion
technologies bring their own issues and limitations. But
memory, power density and inflexibility of design are not
among them.
They are, as a class, susceptible to mistreatment, heat and
fire. Witness the 2013 fire aboard Boeing Dreamliners for
one hint. Or, check out the numerous instances lithium-ion
batteries catch fire because of poor packaging or shipping
issues.
More new technologies in the future ... The
The problem with so many lithium-ion designs stemmed
trick is in the design ... and managing use
from their susceptibility to thermal runaway - a problem
Boeing's 787 fleet suffered a lengthy grounding after
as old as flooded lead-acid batteries.
two incidents in which one of each
The heat of a short or other problem
aircraft's two lithium-ion main-ship
contributes to an increase in heatbatteries overheated and caught
BATTERY MAKERS
producing reaction by the battery, itself
fire, suffering thermal runaway. The
feeding the flames until no fuel exists.
National Transportation Safety Board's
AND USERS HAVE
All these technologies seem to
final report on an incident in Boston
LOOKED AHEAD WITH
share the potential for overcharging
grew out of faulty battery design and
EXPECTATION OF
or charging too rapidly to initiate a
production; while neither of the two
thermal runaway.
battery failures involved overvoltage
The worst element of most lithiumduring charging, both batteries suffered
ion batteries stemmed from their
with significant heat prior to the
reaction to heat - a byproduct of shorts
thermal-runaway event.
in or of the batteries or between more
Accurate, appropriate charging
FOR YEARS, A
than one battery. It's again that old
control takes on a higher level of
nemesis, thermal runaway.
importance with the new lithium-ion
SEARCH THAT'S
The problem carries serious
chemistries employed today.
TAKEN AVIATION
implications in cellphones, notebook
Back in 2013, Popular Science noted
THROUGH SEVERAL
and tablet computers; the burns can be
the approach of embedded healthsavage, with a very real threat of a fire
electronics technology in new batteries
ALTERNATIVE BATTERY
spreading.
to help them manage their own health
CHEMISTRIES.
Imagine a thermal-runaway fire on
and improve their lifespan.
an aircraft ... particularly an aluminum
That prediction came in perfect
aircraft ... now add that it's in flight.
timing with the emergence of new
The structure of an aluminum aircraft
battery technology of the lithium- the aluminum itself - can, in fact, burn and feed such a
ion bent on eliminating that thermal-runaway problem. The
fire, limiting their appeal in aircraft and raising the stakes for
higher-power versions of these systems are designed for
certification and acceptance.
turbine-engine aircraft with their own internal charging and
Any in-flight fire instantly poses a major crisis for any
monitoring electronics, electronics which can communicate
occupants until the aircraft lands and the humans vacate.
with cockpit systems that keep the crew aware of the battery's
An in-flight fire fed by the burning part's own fuel
health and status.
exacerbates the major. So when shipments of lithium-ion
Companies like Concorde that eliminate lead-acids
batteries caught fire in-transit, well, that kicked up the issue
from their lines aren't missing out on much, their insiders
several notches, leading to bans on air-shipping lithium-ion
confide. Even without demand shrinking, costs of handling

BE T T E R , L I G H T E R
A ND E CO NO M I C A L
A LT E R NAT I V E S

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Avionics News March 2015

Table of Contents for the Digital Edition of Avionics News March 2015