So what caused the battery explosion?
The exploding battery was caused by a few contributing factors but the main issue was a short in the battery. Small devices like the Note 7 and many other if not all phones are powered by lithium ion batteries which consist of highly reactive and flammable elements such as lithium and carbon. These elements are able to store energy in the form of positive and negative electrodes which are separated only by an extremely thin piece of micro-perforated plastic. In the first batch of defective batteries, the positive and negative layers were squished at the top right of the battery, and part of the negative layer was pushed into the positive layer which caused a short and resulted in a phone on fire. After a few reported cases of this, Samsung recalled all the phones and soon issued replacement phones and shortly after even those phones began to explode. Due to constant competition between the companies that manufacture cell phone batteries, these batteries are packed as tightly as possible. The more layers packed into the battery, the more powerful it will be. Different from the last defect, these batteries were said to be packed too tight and the layers separating the positive and negative poles were punctured. The defect in the second batch of batteries was once again, poor manufacturing of the batteries. The manufacturer did a poor job welding the positive layer with the rest of the battery, and left a small piece of material loose inside the battery. With the battery being pressed so tightly together, it was basically a ticking time bomb. With some of them worse than others, it was only a matter of time before the poor construction gave and the extremely flammable chemicals inside caught fire. There is also a process called “plating” in which the lithium ions inside the batteries start to coat the surface of the negative contact. In some extreme cases such as in some the Note 7 explosions (second defect), the lithium metal that coats the contacts forms tiny spikes (called “dendrites”) that can puncture the separator creating a short circuit. In some of the batteries, the insulation tape that insulates the two layers (positive and negative) was completely missing which leads to a defective battery.
The second production of defective batteries is what really hit the nail on the head for Samsung. How will customers react when the Note 8 arrives? Fearful of another explosive phone? Hopefully not, Samsung has big plans to perfect their devices from now on. They will do so by implementing a new battery testing protocol that should make phones safer and prevent any unseen issues along with upgrading their staff and be more cautious of design flaws. Profits suffered for Samsung, it is said the recall ran the company about $5 billion in all. Samsung hopes the Note 8 will help buyers forget about the Note 7 woes.
Links:
https://www.cnet.com/news/why-is-samsung-galaxy-note-7-exploding-overheating/
https://www.cnet.com/news/samsung-galaxy-note-7-return-exchange-faq/