Note 7’s flaw ‘doesn’t fully answer burning question’
SEOUL, South Korea: Samsung’s recall of 2.5 million Galaxy Note 7 phones after several dozen caught fire and exploded may stem from a subtle manufacturing error, but it highlights the challenge electronics makers face in packing ever more battery power into ever-thinner phones, while rushing for faster release dates.
Announcing the recall on September 2, Samsung confirmed that dozens of Note 7 batteries had caught fire or exploded, most of them while being charged.
It is planning a software update that will cap battery recharging at 60 percent capacity to help minimise risks of overheating.
It is urging owners to keep the phones turned off until they can get them replaced in a campaign that begins on Monday.
When it was launched last month, the Note 7 received rave reviews for its speed, new software features and – not least – the estimated nine hours it would run between charges.
But then users began reporting the phones were catching fire or exploding, in one case incinerating the SUV in which it had been left.
Aviation authorities in the US, Australia and Europe have urged passengers not to use or charge Note 7s while flying and not to put them in checked baggage.
On Monday, Canada issued an official recall.
Koh Dong-jin, Samsung’s mobile president, said an investigation had found a “tiny error” in manufacturing was responsible. The end of the pouch-shaped battery cell had flaws that increased the chance of stress or overheating.
Park Chul Wan, a former direc- tor of the next-generation battery research centre at the state-owned Korea Electronics Technology Institute, said this kind of manufacturing error was unimaginable for topnotch battery makers with adequate quality controls.
He suggested Samsung search for factors outside the battery cells that could have led to overheating.
“It does not appear to be a simple battery problem.”
Before news of battery explosions emerged, supplies had not been keeping pace with demand for the Note 7.
Samsung has not recalled Note 7s sold in China.
It has refused to say which of its two battery suppliers made the faulty batteries and which batteries are used in which Note 7 smartphones.
CW Chung, an analyst at Nomura Securities in Seoul, cited Samsung SDI officials in estimating that 70 percent of the batteries were from their company.
The rest are thought to have been supplied by Amperex Technology, a manufacturer in China that is said to be a main supplier of batteries for the iPhone.
Problems with lithium batteries have affected everything from laptops to Tesla cars to Boeing’s 787 jetliner.
The batteries are lightweight and pack far more energy into a small space than other power cells. But if the separators fail, a chemical reaction could lead to disaster.
That’s what happened with the Note 7, Koh said.
“The flaw in the manufacturing process resulted in the negative electrodes and the positive electrodes coming together.”
South Korean experts have suggested Samsung might have been so ambitious with the Note 7’s design it compromised safety.
But Lee Sang-yong, a professor at Ulsan National Institute of Science and Technology who worked at LG Chem, a leading lithium battery maker, for more than 10 years, said thicker separators could improve safety, but would not necessarily prevent all overheating issues.
However, Doh Chil-Hoon, head of the state-run Korea Electrotechnology Research Institute’s battery research division, said if there had been enough elements to ensure safety, it would not explode.
A spokeswoman at iFixit, which publishes repair guides for electronic gadgets, said the problem was probably only a manufacturing defect. – AP