Recent events in Florida where a man had his e-cig mod blow up in has face has been all over the news, and this has quite rightly raised concern within the vaping community. At present all reported explosions of ‘e cigs’ have involved ones that are metal tube ‘mods’ and had two batteries stacked on top of each other.
Single battery mods and regular electronic cigarettes – e.g. the 510 are not implicated – the reasons for this are listed below.The explosion in Florida – it appears – was from a modified metal tube e-cig that had paired/stacked RC123 size battery cells – which are 16340 size batteries.
So why did the mod explode because it was a metal tube mod and had paired/stacked batteries? Aren’t all e-cigs metal tubes? Yes, but the explosion occurred probably because the design was not good enough, and it did not have enough safety features incorporated into it, plus smaller stacked batteries may not be ‘up to the job’ and hence fail.
All lithium batteries can suffer from what is called ‘thermal runaway’ where they become very hot and vent off gas; this following explanation is taken from the web, the link is provided after the excerpt, and bracketed words are mine: (Over heating or a fire within the electronic cigarette) is usually caused by an internal short in the battery. Lithium-ion cells contain a separator sheet that keeps the positive and negative electrodes apart. If that sheet gets punctured and the electrodes touch, the battery heats up very quickly. You may have experienced the kind of heat a battery can produce if you have ever put a normal 9-volt battery in your pocket. If a coin shorts across the two terminals, the battery gets quite hot. In a separator failure, that same kind of short happens inside the lithium-ion battery. Since lithium-ion batteries are so energetic, they get very hot. The heat causes the battery to vent the organic solvent used as an electrolyte, and the heat (or a nearby spark) can light it. Once that happens inside one of the cells, the heat of the fire cascades to the other cells and the whole pack goes up in flames
The following stage on from the thermal runaway would be an explosion. If there is insufficient escape routes for the gas and possible flames to escape, i.e. vent holes, then the law of physics states that the tube containing the batteries will explode. Design and engineering are crucial with all things electrical, and electronic cigarettes are no different.
The electronic cigarettes that Totally Wicked sell have safety features incorporated within the design and batteries. The 510 have built in protection and a battery end blow out plug (the LED). Thermal runaway may occur, but there have been no reports of explosions.
The eGo series of electronic cigarettes again have built in circuit protection, vent holes, though no blow out plug. Thermal runaway may occur, but there have been no reports of explosions.
To put this into perspective. Anything that has a lithium battery carries a risk. Below are a few newspaper articles where mobile phones have exploded – including an iPhone 4.
Much of the information in this post was taken from the ECF, (link provided below) this is well worth a read as it goes into far more detail, and gives great advice regarding battery care.