“A battery is a device that is able to store electrical energy in the form of chemical energy, and convert that energy into electricity,” says Antoine Allanore, a postdoctoral associate at MIT’s Department of Materials Science and Engineering.
Batteries can be used to power portable devices. They let devices use electricity without the need to be plugged into main electricity sources, such as wall sockets. Mobile phones, tablets, the TV remote and torches all use batteries. Some batteries are rechargeable so they can be used again and again.
Batteries are used to store chemical energy. Placing a battery in a circuit allows this chemical energy to generate electricity which can power device like mobile phones, TV remotes and even cars. Generally, batteries only store small amounts of energy. More and more mobile devices like tablets, phones and laptops use rechargeable batteries.
Once charged, the battery can be disconnected from the circuit to store the chemical potential energy for later use as electricity. Batteries were invented in 1800, but their chemical processes are complex.
Batteries —handy, convenient power supplies as small as a fingernail or as big as a trunk—give us a sure and steady supply of electrical energy whenever and wherever we need it. Although we get through billions of them every year and they have a big environmental impact, we couldn't live our modern lives without them.
When you unplug the power and use your laptop or phone, the battery switches into reverse: the ions move the opposite way and the battery gradually loses its charge. Read more in our main article on how lithium-ion batteries work.
OverviewHistoryChemistry and principlesTypesPerformance, capacity and dischargeLifespan and enduranceHazardsLegislation and regulation
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons. When a battery is connected to an external electric load, those neg…