Battery, electrical woes complicate Boeing 787 investigation
WASHINGTON (AP) - The battery that caught fire in a Japan Airlines Boeing 787 in Boston earlier this month was not overcharged, but government investigators said there could still be problems with wiring or other charging components.
An examination of the flight data recorder indicated that the battery didn't exceed its designed voltage of 32 volts, the National Transportation Safety Board said in a statement.
NTSB investigators are continuing to look at the battery system. They plan to meet Tuesday with officials from Securaplane Technologies Inc., manufacturer of the charger for the 787s lithium ion batteries, at the company's headquarters in Tucson, Ariz., said Kelly Nantel, a spokeswoman for the board.
"Potentially there could be some other charging issue," Nantel said. "We're not prepared to say there was no charging issue."
Even though it appears the voltage limit wasn't exceeded in the case of the Japan Airlines 787 battery that caught fire on Jan. 7 in Boston, it's possible that the battery failures in that plane and in an All Nippon Airways plane that made an emergency landing in Japan last week may be due to a charging problem, according to John Goglia, a former NTSB board member and aviation safety expert.
Too much current flowing too fast into a battery can overwhelm the battery, causing it to short-circuit and overheat even if the battery's voltage remains within its design limit, he said.
"The battery is like a big sponge," Goglia said. "You can feed it with an eye dropper or you can feed it with a garden hose. If allowed, it will soak up everything it can from the garden hose until it destroys itself."
There are so many redundancies and safeguards in aviation that when an accident or mishap occurs, it almost always is the result of a chain of events rather than a single failure, he said.
The Japan Airlines plane caught fire Jan. 7 while it was sitting on the tarmac at Boston's Logan Airport. In a separate incident on Jan. 16, an ANA flight made an emergency landing in western Japan after a cockpit message warned of battery problems and a burning smell was detected in the cockpit and cabin. An investigator in Japan said Friday that the burned insides of the plane's lithium ion battery show the battery received voltage in excess of its design limits.
Since then, all 50 787s that Boeing has delivered to airlines' fleets have been grounded, and the manufacturer has halted deliveries of new planes until it can address the electrical problems.
The batteries in two incidents "had a thermal overrun because they short-circuited," Goglia said. "The question is whether it was a manufacturing flaw in the battery or whether it was induced by battery charging."
An examination of the flight data recorder indicated that the battery didn't exceed its designed voltage of 32 volts, the National Transportation Safety Board said in a statement.
NTSB investigators are continuing to look at the battery system. They plan to meet Tuesday with officials from Securaplane Technologies Inc., manufacturer of the charger for the 787s lithium ion batteries, at the company's headquarters in Tucson, Ariz., said Kelly Nantel, a spokeswoman for the board.
"Potentially there could be some other charging issue," Nantel said. "We're not prepared to say there was no charging issue."
Even though it appears the voltage limit wasn't exceeded in the case of the Japan Airlines 787 battery that caught fire on Jan. 7 in Boston, it's possible that the battery failures in that plane and in an All Nippon Airways plane that made an emergency landing in Japan last week may be due to a charging problem, according to John Goglia, a former NTSB board member and aviation safety expert.
Too much current flowing too fast into a battery can overwhelm the battery, causing it to short-circuit and overheat even if the battery's voltage remains within its design limit, he said.
"The battery is like a big sponge," Goglia said. "You can feed it with an eye dropper or you can feed it with a garden hose. If allowed, it will soak up everything it can from the garden hose until it destroys itself."
There are so many redundancies and safeguards in aviation that when an accident or mishap occurs, it almost always is the result of a chain of events rather than a single failure, he said.
The Japan Airlines plane caught fire Jan. 7 while it was sitting on the tarmac at Boston's Logan Airport. In a separate incident on Jan. 16, an ANA flight made an emergency landing in western Japan after a cockpit message warned of battery problems and a burning smell was detected in the cockpit and cabin. An investigator in Japan said Friday that the burned insides of the plane's lithium ion battery show the battery received voltage in excess of its design limits.
Since then, all 50 787s that Boeing has delivered to airlines' fleets have been grounded, and the manufacturer has halted deliveries of new planes until it can address the electrical problems.
The batteries in two incidents "had a thermal overrun because they short-circuited," Goglia said. "The question is whether it was a manufacturing flaw in the battery or whether it was induced by battery charging."
The NiCad battery pack for my Sears Craftsman drill is relatively simply, just a temperature sensing thermostatic switch deep inside that opens the output terminals if the battery pack temperatrue rises too high, charge or discharge cycle.
Open up the Li-ION one and wow, surprise at the complexity. A multi-layer circuit board with lots of surface mount electronic componets and 2 major power transistors.
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I have noted that with the Li-ION under heavy use the circuit will open as if the Li-ION is suddenly fully discharged. I can set the drill aside for few moments (to cool?) and then it will again work just fine.
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So I would imagine that Boeing problem has more to do with the charge or discharge RATE rather than actual terminal voltage. But how do you control the charge rate, or discharge rate, of Li-ION batteries when they're HARD-WIRED to the planes 28 volt bus?
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They may have to think, "Out of the Box" in order to get this fixed. al_wa seems to have a good approach. It could take some time to get to the Root cause....
Scrap that ill conceived heap before someone gets hurt.
 @T_BONE_WALKER Troll!
Based on your logic the Model T never would have come to be.
 @T_BONE_WALKER 848 orders for the 787 is hardly ill conceived. A very large part of those sales end up in the pockets of employees in the the Seattle area and the businesses they patronize.
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@T_BONE_WALKER It is far from an "ill conceived heap". The problems are more than likely from a vendor part...the battery or battery charger. You can't fault the entire plane for one bad part.
The cells in a lithium battery over time become more and more unbalanced, meaning some will charge faster than others. Charging a Lithium cell beyond 4.20 volts creates heat and potential thermal runaway resulting in self sustaining fire (generates it's own Oxygen from the breakdown of the Lithium Cobalt Oxide.) Charging a multicell lithium battery requires the charger monitor each cell voltage and if it is different then other cells it will shunt the cell (discharge) until the cell falls within the charge voltage of the other cells. Insufficient authority (shunt current) can allow that cell to charge beyond 4.2 volts. The failure of a single cell can propagate through the battery. The charger is a software driven machine, so lots of things to go wrong with the charging process, hardware, software, design requirement, design implementation.  Boeing and all of it's helpers will figure this out.
 @al_wa Beautiful description.
 @TheLogicOne Thank you.