The Samsung Galaxy Note 7 gained notoriety many years ago when its batteries caught fire in a series of incidents. Since then, there has been a steady stream of similar, albeit isolated, incidents. However, despite the high level coverage of batteries gone bad, the vast majority of Li-ion batteries are safe.
The chemical reaction that takes place inside a lithium-ion cell is complex, but like any battery, there is a negative electrode and a positive electrode. In lithium batteries, the negative is a lithium carbon compound and the positive 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 headphones melting in your ears.
What changes a safe reaction to an uncontrolled reaction can be any number of things: excessive heat, physical damage during use, physical damage during manufacture, or using the wrong charger.
The three basic rules that have kept me safe (so far) when testing dozens and dozens of batteries are:
- Avoid cheap cords, chargers, and outlet adapters.
- Make sure the batteries are not exposed to excessive heat (over 110 degrees).
- Regularly inspect the batteries for any signs of damage.
Most importantly, avoiding inexpensive wall outlet adapters, cords, and chargers. These are your most likely sources of trouble. Those chargers you see on Amazon for $ 20 less than the competition? It’s not worth the shot. They probably lowered the price by skimping on insulation, leaving out power management tools, and ignoring the basics of electrical safety. The price alone is not a guarantee of safety either. Buy from reputable companies and brands.
Then there is the heat. Too much can cause all kinds of problems, both in terms of discharge and in terms of safety. Avoid heat and be careful of your batteries when charging them. If your device gets too hot while charging, it could be a sign of problems.
Likewise, beware of swollen, bulging, or deformed batteries.