US engineering consultancy firm Instrumental believes it has found why Samsung’s now defunct Note7 phablet was catching fire. It says there was too much battery packed into too small a caseThe Note 7 battery was made up of a positive layer of
lithium cobalt oxide, a negative layer of graphite and a layer to separate the
two materials.

The middle layer allowed energy to flow between the positive and negative
layers. But if those layers touched. it would cause the battery to overheat and
explode.

Instrumental said that adding pressure on the battery, such as a user sitting
on the phone, could be enough to squeeze the layers together causing them to
touch, overheat and catch fire. Samsung has declined to comment.