Focus on the Boeing 787′s mishap last Monday comes, naturally, on the fire involving the lithium-ion battery. The battery, or Li-ion for short, is considered hazardous in many applications and in air cargo shipping.
Two Boeing 747-400 cargo planes were carrying a large shipment of Li-ions. One for sure–UPS in Doha–crashed after these batteries caught fire. Another, a Korean Air Cargo flight, was carrying a large shipment. The airplane crashed into the ocean and if the cause was traced to these, we haven’t seen it–but the suspicious arose early.
While the 787′s use of Li-ion has attracted headlines, the use in airplane applications is more common than has been recognized.
The Airbus A380 uses lithium batteries to power its emergency lighting system. The US FAA set special conditions when certifying the aircraft. Airbus says “the batteries are small, limited, and are not in a frequently-active charging/discharging function.”
Airbus also has looked at new ways to generate electricity aboard the aircraft itself. The A350 XWB features a new lithium-ion battery that marks a significant improvement on the Cd-Ni unit used in other models.
The battery contains less hazardous material, which makes it safer to handle. Adding to the benefits, it has a higher power and energy density, and low maintenance requirements, all while lasting up to three times longer than the Cd-Ni.
Aviation International News looked at issues surrounding Lit-Ion batteries last October. Acting upon the recommendation of Cessna, the FAA ordered removal of Lit-ion batteries from the CJ4 corporate jet. A couple of other corporate jets have these batteries.
AIN had this story about stricter rules transporting Li-ion batteries, in which the hazards are discussed.
One of our regular readers and commenters notes that “the A350 architecture… has four 28v Li-ion batteries, meaning there are 28 Li-ion cells on-board…, compared with only 14 on the 787…. Clearly a huge cause for concern… unless Airbus designs the A350 to properly manage this known failure mode, which I am sure they have done.”
The cause for concern involving Li-ion is a condition called thermal runaway. The same reader immediately above, a Boeing employee, also wrote, “Thermal runaway is a known failure mode for Lithium-ion batteries, as it is for Ni-Cad. The 787 is designed to manage this exact failure. The evident lack of damage to the JAL airplane (plainly visible in the NTSB photo) is a testament to this fact.”
The electronics bay doesn’t have a fire suppression system. A Boeing employee told us that the bay has relatively few flammables and they are all known (i.e. the battery), so it is an easy problem to design the compartment to handle that fire event. He adds that the reason cargo holds need suppression is because they contain flammables which are an unquantified variable and cannot be reasonably contained as a part of the design, outside of a suppression system.
An aside: Readers know we have a warped sense of humor. We found the following in the Comment section on The Seattle Times and thought it a pretty funny quip. Boeing, as we all know, says the issues with the 787 are teething problems. Says a Times reader:
“The Boeing Dental Plan will cover these teething problems will 787 is going to be toothless soon.”