Batteries play a wide, critical and growing role in all of our lives. Applications like electric vehicles and airplanes are pushing performance demands for lithium-ion batteries to their limits. To make sure that these and future applications are safe, reliable and energy efficient, we need to boost research into technologies that advance battery safety while maintaining performance.
Lithium-ion battery safety is of national concern and demands national leadership and support. In the wake of this month’s National Transportation Safety Board’s report on how shortcomings in design and certification led to a 2013 fire in a lithium-ion battery on a Boeing 787 Dreamliner, it is crucial that we focus on developing safer lithium-ion batteries.
Batteries used in mobile phones and laptop computers, which can spontaneously combust, will destroy an average of one U.S.-registered cargo jet every other year, one government analysis concluded.
The NTSB report underscores the imperative to act. The lithium-ion battery that provided electricity to the auxiliary power unit of the Dreamliner parked at Boston’s Logan Airport ignited on January 7, 2013. Maintenance crews found heavy smoke and a small 3-inch flame coming from the battery housing. Nine days later, the main battery on an All Nippon Airways Dreamliner failed during a flight over Japan. No fire was observed, and damage was confined to the battery housing.
"This type of failure was not expected based on the testing and analysis .... that Boeing performed as part of the 787 certification process," the NTSB wrote at the time. The NTSB said that, in seeking certification for using lithium-ion batteries, Boeing successfully passed all nine testing requirements. The outcome was that they estimated that a “smoke” event would occur “less than once in 10 million flight hours.” But after less than 52,000 hours of commercial flight, two batteries failed, one culminating in a fire, the NTSB noted.
Clearly current testing protocols are inadequate. The risks associated with internal short circuits and thermal “runaway” need to be addressed.
In its report, the NSTB recommended that the Federal Aviation Administration develop more oversight to ensure manufacturing standards are adhered and work with aviation industry experts to develop or modify design safety standards for large-format lithium-ion batteries to assure that sources of excessive heat be identified, minimized, and documented. They also urged the FAA to work with lithium-ion industry experts to conduct research into battery monitoring system technologies that could improve the recognition of conditions leading to thermal runaway, among other things.
The early issues with the Dreamliner batteries (which have since been reengineered to meet new safety standards) point to the need for additional research into technologies that can increase safety and prevent small faults from cascading into dangerous chain reactions.
Some research has begun. For example, Battelle and Concurrent Technologies Corporation (CTC) are collaborating to find ways to increase battery safety while minimizing weight concerns for the next generation of high-performance battery-operated applications.
We believe that there are four critical areas needed in order to advance safety as we continue to seek higher levels of battery performance -- sensors for local fault detection, diagnostics for local fault detection, enhanced local safety features and intrinsically safer materials.
Developments in these areas are underway and some are already starting to appear in the newest high-performance batteries. However, to meet the increased performance demands we expect from tomorrow’s personal devices, vehicles, and power grid applications, we need to continue to make battery safety research a priority.
Promising new innovations, such as internal fault sensors, advanced controls, and thermal isolation methods, are pointing the way to safer, more reliable batteries that balance the need for lower weight and higher energy density with safety concerns. To power the future, we need to make sure that battery safety research gets even more emphasis.