There’s Finally An Explanation As To Why Samsung Note 7s Kept Kaboomin’

The Samsung Galaxy Note7 shitstorm has more or less passed now that the company has abandoned ship and ended production of the phone, but the question still lingers: why the hell were they exploding in the first place?

We may have a somewhat credible answer – and it’s actually not the battery chemistry or design, according to the fine folk at consumer tech engineering firm Instrumental. As they state: if it was just the battery that cooked itself, why didn’t Samsung just respin the battery part, slot it into the new phone and go on their merry way?

Basically, the Note7 was victim of the endless smartphone arms race for the thinnest device imaginable. The device is very thin and Samsung is generally less willing to compromise on long battery life than, say, Apple. 

So you’ve got a big-ass battery operating within exactingly thin manufacturing standards – and the guys at Instrumental reckon that’s a recipe for disaster. The technical explanation is here, if you’re willing to wrap your noggin ’round it:

The Note 7’s lithium-polymer battery is a flattened “jelly-roll” consisting of a positive layer made of lithium cobalt oxide, a negative layer made of graphite, and two electrolyte-soaked separator layers made of polymer.  The separator layers allow ions (and energy) to flow between the positive and negative layers, without allowing those layers to touch.  If the positive and negative layers ever do touch, the energy flowing goes directly into the electrolyte, heating it, which causes more energy to flow and more heat — it typically results in an explosion. Compressing the battery puts pressure on those critical polymer separator layers that keep the battery safe.  Samsung stated that these separator layers may have been thin to start with due to aggressive manufacturing parameters.  Add some pressure due to normal mechanical swell from the battery or accumulated stress through the back cover (e.g. from being sat on in a back pocket), and that pressure could be enough to squeeze the thin polymer separator to a point where the positive and negative layers can touch, causing the battery to explode.

Long story short? There’s really not much room in the phone to accommodate a very normal battery swell. Which means that for Samsung to actually solve the damn problem, they’d either have to invent a battery which doesn’t swell even minutely (not gonna happen) or redesign the phone altogether (very spenno).