The Galaxy Note 7 which was expected to lead the Samsung’s sales in the festive period has turned into a disaster after the innumerable issues of its batteries overheating and exploding.

Following its many phones bursting into flames, Samsung was forced to issue a global recall and the debacle has also got it banned from planes with regulators strongly advising its customers to not use it further. Not only that, the devices are also being blamed for fires that destroyed a Jeep and did serious damage to a garage. Meanwhile, sales in India have also been suspended following the fiasco.

What is the reason that the phone has turned into such a fire hazard? Here's what experts say:

  • The Note 7 has a 3,500 mAh lithium-ion battery. Lithium, as many of you might not know, is a metal that can catch fire when exposed to oxygen or water. So, the companies use such batteries with additional safety measures, but faulty ones with poorly made electric circuitry can meet with fiery ends, Lloyd Gordon, the chief electrical safety officer told Live Science.
  • These faulty batteries when overcharged and if left plugged in for too long can cause accumulation of lithium ions which get deposited as metallic lithium within the battery and react with oxygen. Defective lithium-ion batteries can also be over-discharged, meaning they don't shut off when the power is too low, which can also lead to fires, Gordon said.

Talking to Forbes, Donal Finegan, a chemical engineer at University College London said,
  • Lithium-ion cells are great at powering gadgets which makes them vulnerable to catching fire. “They are so energy-dense and can operate under such high power that they can combust in a particularly catastrophic way.”
  • He further explains that one cause of combustion can be with the battery management system that monitors the electrical current and tells a chip inside the phone to stop the current once a battery is fully charged. If either the system or chip is faulty, a battery can enter a state of “overcharge. In such a situation, the battery can continue to charge and can become even more unstable and eventually just burst into flames itself, without any kind of external heating.

Dr. Donald R. Sadoway, the John F. Elliott Professor of Materials Chemistry at the Massachusetts Institute of Technology had another theory. He explained to Time,

  • ''It’s either a statistical fluke in the manufacturing process where there are some local hotspots or there are perhaps some metal shavings, some kind of a shorting. But it seems as though, the fires occurred when the owners are charging the phone. That means that while they’re forcing current through it, somehow there is a side reaction that is very different from just recharging the battery. And that starts charging the battery, and then the thing goes into thermal runaway.''

What's next?

The company said it would temporarily halt sales of the device, and that it would replace current Galaxy Note7 smartphones with newer, safer models in the coming weeks.