Samsung detailed its findings in a press conference in Seoul today. Led by DJ Koh, Samsung’s President of its Mobile Communications Business, the event opened with a formal apology for the disastrous issues with the Galaxy Note 7.
Samsung said it examined every part of the Note 7 to ascertain the root cause of the battery fires. It looked at the phone’s hardware components, firmware, operating system and other attributes before reaching its conclusion. Three independent industry organisations, UL, Exponent and TUV Rheinland, have verified the company’s results.
Negative electrode deflection
The explosions were enabled by two manufacturing problems that allowed the positive and negative battery electrodes to meet, causing a short circuit. As previously rumoured, the Note 7’s battery was marginally too large for its casing, causing the negative electrode to be pinched inwards at the upper-right corner of the battery. This deflection of the electrode allowed plates to touch, short circuiting the connection.
The placement of the negative electrode’s tip proved to be another factor. Ordinarily, the electrode’s tip should be located within the flat, planar area of the battery coil. The Galaxy Note 7’s electrode tip was incorrectly placed within the curve of the coil.
Welding burrs
Samsung admitted that the supposedly “safe” batteries in its replacement devices could also short circuit, due to a different issue. High welding burrs on the positive electrode penetrated the insulating tape and separator between the positive and negative electrodes. This enabled direct contact, causing an immediate short circuit.
Samsung also found that some replacement devices lacked insulation tape altogether. It hasn’t explained how this occurred. The company appears to have rushed the production of the replacement handsets, causing more critical errors to be introduced. Samsung executives apologised to customers, mobile operators and retail distribution staff who have been affected by the oversights.
“For the last several months, together with independent industry expert organisations, we conducted thorough investigation to find cause to the Galaxy Note7 incidents,” said Koh. “Today, more than ever, we are committed to earning the trust of our customers through innovation that redefines what is possible in safety, and as a gateway to unlimited possibilities and incredible new experiences.”
Future safety measures
In the wake of the disaster, Samsung has introduced new quality assurance stages to prevent similar problems occurring in the future. It now runs an 8-Point Battery Safety Check that assesses batteries for a range of manufacturing defects. It visually inspects batteries, x-rays them to look inside and runs a test suite that includes charging, discharging, overcharging, puncturing and extreme temperature stresses.
The company has also implemented additional safety protocols that enforce safety standards on every element of new phones. Finally, it has formed a battery advisory group of external advisors to help it continue to innovate in battery safety “with a clear and objective perspective.”
Samsung appears to be committed to preventing its future handsets from becoming repeats of the Galaxy Note 7. It concludes its investigation after several months of work, putting an end to previous speculation and allowing it to move on from the incidents. The company has also confirmed it will continue to use its Galaxy Note brand going forward, opening the door to a less fire-prone Galaxy Note 8 later this year.
Samsung has created an infographic explaining its findings from the Note 7 investigation. It can be found at the Samsung Newsroom.
