The Problem with the Batteries
The reason for the problem was a short circuit. The lithium battery has layers. The center is a Pouch; the next layer is the negative electrode followed by the separator and positive electrode. Damage to the separator between positive and negative electrodes caused the short circuit.
Two examples show the damage. One example shows a battery where the right corner bends the layers over. This bend causes damage to the separator. The solution is to keep the layers out of the curve.
The second example shows high welding burrs on the positive electrode. These high welding burrs penetrated the separator and insulation tape. The positive electrode would then meet the negative electrode and short circuit. Some batters were also missing insulation tape.
Samsung Announce New Safety Procedures
Following the findings, Samsung has announced new measures to make sure this doesn’t happen again. The result is an 8-Point Battery Safety Check. Batteries will go through a durability test, visual inspection, x-ray, charge and discharge test, TVOC test (Total Volatile Organic Compound), disassembling test, accelerated usage test; and an OCV test (Delta Open Circuit Voltage).
Other safety measures include improved battery design; improved hardware design, like new brackets for battery protection; improved software algorithms to track temperature, battery charging, current charge and charging duration.
Samsung phones are still selling, but maybe not as well as they could be.
“For the last several months, together with independent industry expert organizations, we conducted the thorough investigation to find cause to the Galaxy Note7 incidents.” DJ Koh, President of Mobile Communications Business at Samsung Electronics said, “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.”