Lithium Ion Battery and e-Cigarette Fires and Explosions

Failures (fires and explosions) of Lithium ion batteries in e-Cigarettes, roller boards, computers or cell phones are most commonly caused by shoulder wear and shorting at the positive end of the battery.  As for e-Cigarettes, the defectively thin wrapper wears through at the positive end shoulder exposing the negative terminal to the positive end as shown below in Figure 1:

Figure 1.  Exemplar 18650 lithium ion battery (left), CT scanned (right).

The negative terminal consists of the bottom end of the battery, as shown above, the side walls and top edge or shoulder at the positive end of the battery.  If the thin polyester plastic wrap material (typically 3.5 mils thick, approximately the thickness of a human hair) on the outside of the battery is worn away at the positive end shoulder, the negative and positive terminals are only 1 mm (0.039 inches) apart.  Coupled with a metallic ignition source, e.g. coins, keys, etc., this makes the deceptively small batteries very volatile, indeed, and can cause severe and debilitating injuries. 

            Engineers working with us have determined five inexpensive and available “fixes” the battery manufacturers could and should have employed to prevent these accidents: (1) fusing, (2) fixing and/or gluing in place the existing insulation ring on the positive end, (3) increasing the wrapper thickness, (4) installing a wear resistant ring at the positive end and/or (5) using a built-in protective circuit (PCB) at the positive end.

            We support ongoing research and testing of lithium ion batteries to determine modifications to make them safer, see Figure 2 below:

Figure 2.  Pictures of lithium ion battery shoulder short tests in the ongoing.

            If you have been injured in an accident involving batteries, whether it’s an e-Cig, roller board, computer or cell phone, give us a call at 713-302-1286, we can help!