Wirebook › Glossary › Lithium-ion battery
What is a lithium-ion battery?
In one sentence: The rechargeable battery in phones, tablets, laptops and electric cars, where lithium ions swim from one side to the other through a jelly as it works.
A little more
A lithium-ion battery has two sides separated by a thin layer soaked in a jelly or liquid called the electrolyte. Charging pushes lithium ions across to the negative side, where they tuck in between layers of carbon. Using the battery lets them swim back to the positive side, and that movement is what lets electric current flow through the gadget.
They hold a lot of energy for their weight, which is why almost every phone, tablet, laptop and electric car uses them. They are happiest at roughly room temperature: in the cold the ions move slowly and the battery can't deliver big bursts, and when hot they wear out faster. Charging one below freezing can damage it, so devices block it.
See it in action
- BonusWhy does a full battery die in the cold?Your tablet said 45% and switched off on a snowy hill, then came back indoors.7 min · interactive
- BonusWhy do phones and computers get hot?Heat up a pretend phone with games, charging, a duvet or a sunny car, tug a pretend blanket to feel how insulation traps heat, and watch it slow down to protect itself.9 min · interactive
Do it for real
Free grown-up tools and guides on Tooltern, our sister site. They work in your browser and nothing is uploaded.