Many years ago, the Samsung Galaxy Note 7 rose to prominence when its batteries caught fire in a series of incidents. Since then there has been a steady stream of similar, if isolated, incidents. However, despite the high-profile reporting on battery failures, the vast majority of Li-ion batteries are safe.
The chemical reaction that takes place in a lithium-ion cell is complex, but as with any battery there is a negative and a positive electrode. In lithium batteries, the negative side is a lithium-carbon compound and the positive side is cobalt oxide (although many battery manufacturers are moving away from cobalt). These two compounds cause a safe reaction when controlled and provide energy to your devices. However, when the reaction gets out of hand, you end up with earplugs that melt in your ears. What turns a safe reaction into an uncontrolled reaction can be anything: excessive heat, physical damage during use, physical damage during production or using the wrong charger.
The three basic rules that have kept me safe (so far) through testing dozens and dozens of batteries are:
- Avoid cheap cords, chargers, and wall adapters.
- Make sure batteries are not exposed to excessive heat (over 110 degrees).
- Inspect the batteries regularly for signs of damage.
Avoiding cheap wall socket adapters, cords and chargers is the most important thing. These are the most likely causes of problems. Those chargers you see on Amazon for $20 cheaper than the competition? Not worth it. They probably lowered the price by skimping on insulation, forgoing energy management tools, and ignoring the basics of electrical safety. Price alone is also no guarantee of safety. Buy from reputable companies and brands.
Then there is heat. Too much of it can cause all kinds of problems, both in terms of drainage and safety. Avoid heat and pay attention to your batteries when they are charging. If your device gets very hot while charging, it could be a sign of trouble. Also watch out for swollen, bulging, or otherwise misshapen batteries.