Fake iPhone battery explodes in Chinese customer's mouth  

This is the terrifying moment a 'fake' iPhone battery explodes in a man's mouth when he bites it to check whether it is real. 

The customer asked to inspect the used battery at a second-hand market somewhere in China, but for some reason he puts it to his mouth, the Daily Mail reports.

The lithium batteries found in some smartphones cannot be removed by users and the gadgets have to be carefully taken apart by technicians to reveal them.

Sellers of second-hand phones have also been known to swap out original batteries for cheaper quality variants.

Bizarrely the dubious customer, who was accompanied by a female, decided that biting it would prove whether it was real or fake.

The short clip shows him putting the battery between his teeth and chomping on it, causing the device to burst into flames in his mouth.