When your phone becomes a bomb
A burnt Samsung phone that exploded.
A Jeep ablaze in St Petersburg, Florida after a Note7 phone exploded in it. Picture: US ABC
The damage to the Jeep. Picture: US ABC
How safe are lithium-ion batteries? Consumers are asking this question in the wake of all the cases of batteries overheating and exploding that led to this month’s recall of Samsung Note7 handsets.
On September 2 Samsung announced a recall of more than 2.5 million Note7 handsets including 51,060 Note7s in Australia. At that time the South Korean manufacturer cited 35 incidents of explosions, burns and overheating handsets worldwide. Two cases were confirmed in Australia, including a Note7 belonging to a Melbourne businessman exploding in a hotel room in Perth.
Yet Samsung is not alone in this problem. While the incidence is low, iPhones occasionally explode and heat up too, as do other manufacturers’ phones. In July a Sydney cyclist needed a skin graft after an iPhone exploded in his pocket when he fell off his bike. The melted iPhone stuck to his leg. A student in Maine, in northeast US, suffered burns when she sat on an iPhone 5C in her back pocket, causing it to puncture.
In the case of the iPhones, they appear freak accidents that ruptured the structure of otherwise good batteries.
Despite the volatility of lithium and its chemical derivatives, we trust lithium-ion batteries implicitly not to blow up. With 500,000 to one million people flying at any one time, most with phones, that’s an awful lot of batteries we trust not to cause a single airline incident.
A lithium-ion cell broadly consists of two electrodes, a lithium compound positive electrode (cathode) and a graphite-based negative electrode (anode), and an electrolyte substance. During charging, ions move through an electrolyte substance to the anode. During discharging, they go the opposite way.
But if the electrodes somehow touch, for example if a separator breaks down, there’s a short circuit and a spiralling cycle begins. Electrolyte reacts with chemicals, releasing gas and heat. This accelerates the chemical reaction, releasing more gas and heat. Puncturing an iPhone battery as occurred in the two iPhone examples can unleash this phenomenon, known as thermal runaway.
So a battery that’s safe for ages can suddenly turn into an explosive device.
In the case of Note7, it was due to manufacturer defects. According to reports, battery cells were packed together in a way that put pressure on isolation plates within a cell, allowing electrodes to touch. That led to the thermal runaway incident.
Samsung didn’t name the battery maker but
The Wall Street Journal reported that affiliate company Samsung SDI had named itself. That’s consistent with a teardown review of the Note7 by iFixit.com, which specialises in getting new gadgets and pulling them apart and reporting their component pieces. Their teardown revealed a Samsung SDI battery.
Samsung SDI is the firm that Tesla founder Elon Musk decided not to use in favour of Panasonic for Tesla Model 3 car batteries. Musk’s tweet in June signifying this sent Samsung SDI’s share price down 8 per cent.
The Wall Street Journal reported that Samsung SDI made about 65 per cent of Note7 batteries, while the rest came from Hong Kong-based Amperex Technology, a unit of Japan’s TDK. The Amperex batteries were installed in Note7 phones sent to China, which wasn’t part of Samsung’s 10 country recall.
But 1858 pre-release Note7’s with Samsung SDI batteries made it into China and are being recalled. This week there were reports of two Note7s catching fire in China, and the IMEI (phone identity number) of one wasn’t among the China handsets being recalled. (Update: Samsung says one of these was the result of an external fire.)
How did this overall problem happen? We know that Samsung was super keen to gazump Apple and get a new Note into market before the iPhone 7 launch on September 7. Samsung also was using a bigger battery than for the previous Note5 model. There is pressure on battery makers to cram as much charging capacity into the smallest space and work quickly.
Some suggest that Samsung was rushing manufacturing, but if all the Note7s with Amperex batteries are fine, it may be just a Samsung SDI manufacturing defect. We’ll have to see.
Samsung still faces hurdles before the Note7 issue goes away. First, there are more reports not only of Note7s exploding but fires and explosions of other models.
Last week the
New York Post reported a six-year-old boy sustained burns when a Galaxy Core Prime handset exploded in his hands. The boy reportedly was watching videos on the phone when the battery exploded. There was no indication it was charging.
In Denmark last week Anders Leby, an employee at subscription station TV 2 Play in Odense, noticed the battery inside his older Note4 was warm and smelling “a bit strange” when in a conference room. He immediately sought to remove the battery, which had swollen to twice its size.
“I threw it down on the table and ran away. I reached about 2m away before I heard a loud noise.” That explosion also happened spontaneously without any charging taking place.
Samsung has yet to say what the proportion of defective Note7s have been returned in Australia. But in the US, it was reported that only 130,000 or 13 per cent of one million Note7 devices sold in the US had been returned.
That means there is a continued public safety risk. As of last week, in the US there were 92 reports of overheating batteries, including 26 reports of burns and 55 of property damage.
The poor public response has seen individual US agencies take matters into their own hands. Stockton University in New Jersey announced a ban on students using Note7s on campus. The same applies to New York’s MTA, which operates the city’s vast subway and bus system. And FedEx has refused to transport Note7s back to Samsung.
Australia’s Civil Aviation Safety Authority says individual airlines in Australia have applied their own ban on passengers taking the defective Note7s on to aircraft.
There’s a suggestion that Samsung may force through a system update that will slash Note7 battery capacity by 40 per cent, apparently reducing the safety risk.
The company has begun a rollout of replacement Note7s with different batteries. To distinguish them from defective ones, their packaging has a small black square on the white barcode label along with a white sticker with a blue letter S. Users can check the phone’s IMEI number against Samsung’s database.
With old and new units in circulation together, imposing a ban only on defective ones could prove hard work.
Samsung has paid a huge penalty already. It had $US26bn wiped off its value in the days after the recall and faces a bill of up to $US1bn bill for the recall.
Instead of getting the jump on Apple, it is in a state of paralysis as Apple rallies with the release of iPhone 7/7 Plus products. And it already faces a lawsuit from a Florida man who sustained burns from a Note7 explosion. More are likely. Then there’s its reputation.
But Samsung is a vast multidimensional company producing all types of electronics and will survive. This year, reviewers such as I have rated its S7, S7 edge and, before this issue, Note7, as among the best smartphones around.
It now faces a challenge to overcome public wariness of its phones after this problem.
As for lithium-ion batteries, they will be with us until someone finds a better alternative for efficient mobile battery storage.
http://www.theaustralian.com.au/lif...b/news-story/ad0470a9c715f3195c96c0fe7f4b30a1
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