Samsung is warning consumers to stop using its flagship Galaxy Note 7 smartphone after a spate of battery explosions.
It was the latest in a string of lithium-ion battery fires on products ranging from laptops to hoverboards to airliners -- and a reminder that pushing the technology envelope can sometimes be problematic.
Here are some things to know about the recall and why batteries can be a fire hazard.
How do these batteries work and why do they catch fire?
A lithium-ion battery is a kind of rechargeable battery that uses different materials, one holding positive ions -- the cathode -- and the other holding negative ions -- the anode.
These ions move one way when charging, and back again when discharging -- being used.
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These two layers -- or conductors -- are never supposed to touch, so manufacturers insert separators to keep them apart.
Unfortunately, the chemical reaction that makes batteries work also creates heat. Overcharging the packs -- or charging them too fast -- can lead to fires.
What is the issue with Samsung's batteries?
We don't know exactly, but Samsung has given some clues. It said parts of the battery that should never touch came together due to a "very rare manufacturing process error".
Gadget makers weigh all sorts of factors like performance, cost and safety when rolling out their next-generation technology.
And the race to push more battery life into their latest phone or tablet can lead to unexpected results.
"Smartphone makers are trying to squeeze these batteries into a small, thin package," said Hideki Yasuda, an analyst at Ace Research Institute in Tokyo.
"Since batteries generate energy through a chemical reaction, it's really hard to reduce the risk (of fire) to zero.
"Sometimes convenience comes with a price."
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