Why smartphone batteries explode, and why they may get worse

Samsung has officially recalled the Galaxy Note 7 worldwide, after more than 90 of the large smartphones in the US overheated due to defective batteries. Overheating is, in this case, an understatement, as some owners have claimed their smartphones outright exploded. Exploding lithium-ion batteries actually aren’t so uncommon. As my colleagues Angela Chen and Lauren Goode noted earlier this month, there are many ways for a lithium-ion battery to become dangerous, and they aren’t limi