Toward Solving the Dreamliner's Battery Problem
Senior electrochemical engineer and former battery R&D executive who consulted on the Panasonic NiMH batteries used by Toyota in the Prius, suggests Boeing consider this safer battery chemistry for its troubled 787 Dreamliner.
An open letter to Boeing and to the FAA from a battery professional:
A workable path to resolve the Dreamliner crisis
While the ten-billion dollar Dreamliner fleet remains grounded and airline losses mount with no end in sight, the crisis has reached a stand-off. Boeing insists their battery choice was right and is not considering an alternative, while the FAA needs hard proof regarding the battery’s safety. Hardly a good recipe for crisis resolution.
After three weeks of intensive investigation, the NTSB still hasn’t found a cause for the failures. The charging system has been cleared, and the charred remains of the battery show the location of a fire-initiating short, but not its cause. Something unexpected happened inside the battery and we may never know for sure what and why. Most fires of laptop lithium-ion batteries were caused by hard-to-detect, minute manufacturing defects.
Boeing’s position could be a legal strategy, but it must be most distressing news to the airlines with their 200-million dollar planes sitting idle. Ditto for the pilots who were never too happy about the Dreamliner battery choice, Boeing’s shareholders and the news-following public remember lithium-ion battery recalls after laptop fires.
Both the Thales Group who supplied Dreamliner’s power system and their battery supplier, GS Yuasa, must be worried that they could be hit by lawsuits which will be inevitable if the crisis continues.
The FAA is on the hot seat. Five years ago, they accepted Boeing’s arguments and granted permission to use lithium-ion batteries on the Dreamliner, “if potential fire is contained and fumes vented”. They now have a dilemma – hurting an important domestic industry by doing their job, or becoming discredited if another problem occurs. Traditional methodology for evaluating safety does not seem to work well with lithium-batteries. Boeing reported they accumulated 1.3 million cell-hours of in-flight battery tests, and yet the fires occurred after the 50 planes in service accumulated more than twice as many in-flight cell-hours. The fires also occurred months after the batteries were put in service and on batteries manufactured 10 months apart. How long do you need to test batteries to verify safety of their design and of the manufacturing process? Did hidden manufacturing defects cause the fires? Microscopic particle inclusions too small to be visible on the QA x-ray of the very large cell? The revelation that 10 batteries had performance problems and were replaced by the ANA during their first year of service point to something unexpected happening in Dreamliner’s batteries.
While a solution appears difficult, it needn’t be. Lithium-ion batteries may be the necessary choice for an electric car – where they save the weight of two passengers – but not for an airliner where weight savings equivalent to single suitcase on board a 200-ton plane should not be a real issue.
Following is the logical and possibly fastest path out of the crisis:
• Boeing needs to accept that the lithium-ion battery – while perfectly good for ground vehicles which can be abandoned in case of an accidental fire – is not good enough for an airliner flying between continents with hundreds of passengers aboard. The unfortunate decision resulting in the current crisis was made nearly a decade ago with far less information available. The real mistake is continuing to stick to it. The future of your magnificent plane doesn’t depend on whether the two small battery systems aboard are using lithium-ion technology or a 30-kg heavier, safe and mature nickel-metal-hydride (NiMH) technology. Announcing your decision to change the battery will show real leadership and generate new confidence for the pilots, flying public, airlines and the FAA. This is not accepting blame, just taking a pro-active approach to solve the crisis for good and restore confidence in the Dreamliner and Boeing.
• Develop a temporary compromise fix using existing, airplane-qualified batteries. A temporary fix rigged from battery systems currently used on other Boeing aircraft should be acceptable to the FAA and to all other stakeholders as an interim solution needed to get the planes flying again as soon as possible.
• Start qualifying a NiMH battery system [Editor: Panasonic NiMH used in latest generation Toyota Prius pictured above] whose safety has been demonstrated in 6.5 million hybrid cars produced over the last decade. The NiMH battery is just as maintenance-free as the lithium-ion one. It is reliable and certainly more durable than the batteries used on the Dreamliner. The FAA will be relieved by your decision and should be far more accommodating and quicker than with any fix involving a lithium-ion system. Changing the type of two small, car-size batteries and their chargers is not affecting anything else on the airplane and certainly not the safety. The 95-Ah battery modules and chargers used in the 1997-2002 Toyota electric car RAEV4 were well-tested in over 1200 cars produced, and would be one possible example of a permanent fix. The NiMH packs could still be produced by GS Yuasa, who has long experience with manufacturing this battery type.
The path outlined above should be welcomed by all stakeholders currently held hostage by two small, auxiliary-function batteries that do not have to use lithium-ion chemistry. The sooner Boeing makes the decision, the better for everybody.
Dr. Victor A. Ettel is a consultant who has worked with most producers of rechargeable batteries, including GS Yuasa and Panasonic EV Energy, the supplier of NiMH batteries for Toyota and Honda hybrid vehicles. He writes...
This op-ed, written originally for the New York Times, suggests a ‘path forward’ to resolve the Boeing 787 battery crisis. My background as an electrochemical engineer and former R&D executive, who worked for decades with the global rechargeable battery industry – including GS Yuasa and Panasonic EV (producer of NiMH batteries for Toyota and Honda hybrids) – gives me unique insight into the current issue.
Printed by permission of the author.
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