The cat is out of the bag so to speak when it comes to the dangers of lithium-ion batteries. 

Samsung’s ill-fated Galaxy Note 7 has brought the issue right into the public spotlight. 

But, according to Duncan Geere, science writer for online magazine TechRadar, the Samsung is “only the latest in a long line of gadgets spontaneously catching fire.” 

And Duncan explains just why this happens. 

He said: “To understand why those batteries keep catching fire, first you need to understand how a lithium-ion battery works. On each end there's an electrode - one is positive (the anode) and the other is negative (the cathode). In between is a liquid called an electrolyte. When charging, the lithium ions move to the anode and when discharging they move to the cathode. Pretty simple. 

“The problem comes when they move too fast. The rate at which lithium-ion batteries charge is carefully limited so the lithium doesn't move too quickly  which, incidentally, is why batteries take time to charge. 

“If it moves too fast, lithium plates begin to form around the anode, creating a short circuit and generating heat. That heat, if it builds up, can ignite the flammable electrolyte and you've got a battery fire.

“That's not the only thing that can cause a short circuit. If, during the manufacturing process, small holes are created or fragments of metal are left behind in the casing, then the same thing can happen.”

So now you know!

* People take e-cigarettes and their lithium-ion batteries on board aircraft. A pioneering invention called an AvSax ( can minimise the fire danger on board aircraft in seconds with its unique use of water.

Simply pour at least two litres of water into an AvSax and then drop the burning device into the bag. The water activates a polymer gel inside the bag’s lining causing it to expand around the device. Should the device keep on burning then the AvSax is tough enough to absorb the force.