Note 7 may have been a victim of its design

Latest theory

The latest theory as to why the Note 7 had battery problems suggests that its rather cool thin design made it go bang.

The Note 7 had an absolutely “symmetrical” design as the glass backplate is sloping towards the metal frame with the same curvature as the display at the front.

But according to Phone Arena that design might have put pressure on the unorthodox battery plates.

The steep glass curve made the device the narrowest Note ever. Leaked docs from the Korean consumer protection agency showed that the battery packs made by Samsung’s own SDI subsidiary were slightly larger for their compartment by a hair, and the isolation plates that separate the anode and cathode inside were too close towards the edges.

This meant that it was prone to collapsing under pressure, short circuiting the battery, and causing a thermal runaway. The Koreans also found issues with the packaging of the battery cells, like the insulating tape, which was done by a separate company, as well as the coating of the negative electrode.

While separately these would not create the spontaneous combustion, together they were a dangerous mix. All it would take was a bit of pressure on the isolation plates which would have been provided by the design of the steepest edge curve.

The plates are apparently situated towards the edge of the battery, and, when sealing the waterproof phone tight, the pack might be subjected to a pressure that is higher than normal at the wrong end.

That particular matter does not explain the problems for the second recall. That is because the battery was smaller and fitted better. However, the abnormal pressure from the steeply curved sides remained and that could have been enough on its own to damage the battery.