When a lithium-ion battery is being charged, the ions move from the positive to the negative electrode at a fairly high voltage of 3.7 volts – much higher than the 1.5 volts in a typical alkaline battery. These ions move through a liquid electrolyte which is highly flammable – and that is why when one overcharges a lithium-ion battery, it overheats and can even explode.
To demonstrate, Dr Balaya overcharged a single battery cell, applying more than 5 volts instead of the recommended 4.3 volts. The cell was observed slowly bulging, and then it began to emit smoke before abruptly exploding in a spectacular orange burst.
“If this explosion happened at the pack level, it would be a very massive one,” he pointed out.
Palani Balaya of the National University of Singapore, Centre for Energy Research & Technology (CERT), was featured in Talking point to demonstrate how ans why Lithium Ion batteries explodes.