Scientists claim to have solved the mystery of flammable laptop and cell phone batteries, by finding that "dendrites" are responsible for short circuits that cause the lithium batteries to overheat and catch fire.

There have been several high-profile stories in recent years of iPods, laptops and mobile phones spontaneously combusting, sometimes when they're in the owner's pocket or handbag, or when left unattended at home.

Now, a team at Cambridge University has claimed that the growth of metal fibres, called dendrites, is the main reason why the lithium batteries in mobiles, laptops and other devices overheat and catch light.

According to the scientists, batteries in laptops and mobile phones are designed to charge quickly, but this can cause dendrites to form on the battery's carbon anodes -- and these fibres are one of the main causes of short circuits that cause batteries to overheat and even catch fire.

"These fibres can cause short circuits causing battery to rapidly overheat and catch fire," the 'BBC News' quoted the lead scientist, Prof Clare Grey, as saying. .

The scientists are now hoping to get a better understanding of how dendrites form, and how their development can be halted, using nuclear magnetic resonance spectroscopy to trace their development.

In fact, this would in turn help consumer electronics manufacturers improve the safety of lithium batteries, they have claimed.

Prof Grey said: "These dead lithium fibres have been a significant impediment to commercialisation of new generations of higher capacity batteries.

"Fire safety must be solved before we can get to the next generation of lithium-ion batteries and before we can safely use these batteries in a wider range of transport applications.

"Now that we can monitor dendrite formation inside batteries, we can identify when they are formed and under what conditions. Our new method should allow researchers to identify which conditions lead to dendrite formation and to screen potential fixes to prevent the problem.