Samsung has released the results of the Galaxy Note7 battery investigation via a press conference held in South Korea.
The results show that both batteries, the Samsung SDI used in the initial batch and the Amperex used in the second batch suffered from manufacturing defects.
In Battery A (Samsung SDI) the problem was that the negative electrode was deflected in the upper-right corner of the battery, as well as the negative electrode tip incorrectly located in the curve instead of the planar area.
Battery B (Amperex) had high welding burrs on the positive electrode which resulted in the penetration tape of the insulation tape and separator. In addition to that the batteries were also missing insulation tape.
Samsung worked with UL, Exponent and TUV Rheinland to help with the investigation and they all concluded that the problems lie within the batteries, not the hardware or software.
To prevent this from happening again, Samsung has created an Eight-Point Safety Check as well as a Battery Advisory Group that involves X-ray, durability and OCV testing.