How Do Lithium-Ion Batteries Work?

How Do Lithium-Ion Batteries Work?

October 10, 2019 91 By Stanley Isaacs


So you’re outside chasing around that rare
Squirtle, when BAM–your phone dies! We can’t help you catch Pokémon, but we
can give you three hacks for keeping your phone battery juiced. [Splash] Alright before we get into the hacks–here’s
how your phone battery works. Smartphones, laptops, and Teslas get their
power from rechargeable lithium-ion batteries. All batteries have the same three basic parts:
a positive electrode called a cathode, a negative electrode called an anode, and a chemical
layer called an electrolyte that lets electrical charge flow between the electrodes. In lithium-ion batteries, the electrode combo
is usually a lithium cobalt oxide cathode and a graphite anode. When you plug in your phone, electrons enter
your phone’s battery and cause lithium ions to meet up with them at the anode. Once at the anode, the lithium atoms nestle
in sites between the graphite’s carbon layers. When you unplug your phone, the process reverses:
lithium atoms at the anode start losing their electrons. The electrons zip through the circuit, providing
the current to run your phone. Meanwhile, lithium ions journey through the
electrolyte. They reunite with the electrons at the cathode. These processes keep going until all ions
reach the cathode, causing that dreaded flashing battery symbol. Every time you burn through 100% of the battery’s
charge, which is called its capacity, you take the battery through one charge cycle. Each cycle inches the battery closer to death
by shaving off some of its total capacity. So here’s how to keep your phone’s battery
charge and life lasting longer with science. Hack #1: Avoid heat! Heat does nasty things to lithium-ion batteries. And we’re not talking thermonuclear-level
heat: we’re talking about when you forgot your phone in a hot car or left it in the
sun at the beach. As your phone gets warm, the heat speeds up
the chemical reactions that cause a battery to go kaput. These reactions break down the electrolyte
and form products on the anode. This blocks lithium ions from nestling into
the graphite. Fewer site means less capacity and you’ll
have to charge your phone more often. Even worse, heat can start a “thermal runaway”. Once the cobalt oxide gets hot enough, it
starts a cycle of reactions that throw out more and more heat. All this heat starts to boil the liquids in
your phone’s battery building pressure until the battery EXPLODES!!! Hack #2: Don’t Let Your Phone Die. Lithium-ion batteries don’t need to be fully
discharged before recharging, unlike nickel batteries. Nickel batteries suffer from the “memory
effect”—meaning that unless they’re at 0%, they’ll “forget” part of their
capacity when recharged. But lithium-ions never forget, and they loathe
a full discharge. When you drained your phone to zero, your
phone lost more capacity so your charges won’t last as long. So make sure your phone doesn’t die. If it’s on the verge of death just turn
it off. You can tweet us thanks later. Hack #3: Store at 50% charge. We weren’t kidding about lithium-ions hating
it when you let your phone die. If you’re leaving a fully discharged battery
alone for a while, it could get unstable. Like, the thermal-runaway-and possibly-blow-up
kind of unstable. Fortunately for us, modern batteries trip
a self-destruct circuit before destabilizing. Unfortunately for us, self-destructed batteries
never work again. So if you’re going on vacation to a foreign
country where you won’t be using your phone, make sure the battery is around 50% before
turning it off. And if you’re letting it sit for a longer
period of time, turn it on about every six months to make sure it’s charged to 50%. This way you avoid both self-destruction and
capacity loss. With our simple hacks, you can keep your current
battery in top shape for the next time you go hunting Squirtle. What features do you want to see in your next
smartphone? Let us know in the comments and hey, thanks
for watching.