how come cellphone/external batteries explode but regular double A/triple A batteries don’t?

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Like cell phone batteries, Tesla batteries, electric bikes and so on have potential battery issues but not your triple/double A batteries?

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Anonymous 0 Comments

Alkaline batteries, which include AA batteries, have way lower energy and power density.

Alkaline batteries can contain about 0.5 MJ per kg. Li Ion batteries are about 1.0 MJ per kg. So they contain about twice the energy, and are typically larger than AA batteries too.

The power density is the main thing though. Alkaline batteries have a high internal resistance, and only deliver the total rated energy if it is done at 0.1C, or over 10 hours.

Meanwhile, while it varies a lot, there are plenty of lithium ion batteries that will happily deliver at up to 50C or more, meaning a complete discharge in less than *one minute*. That’s 500 times the discharge rate of an alkaline battery. They can deliver massive amounts of power.

If Li Ion batteries are abused, they can form internal “dendrites”. That’s basically growths of metal. These can act as a wire, short circuiting the battery internally. That lets **all** the power out almost instantly. Meanwhile, the alkaline battery simply can’t deliver energy that fast so there’s less drama.

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