Lithium-ion batteries are the most common kind of battery found in fully electric vehicle and for good reason – they have some of the best energy density(energy per square inch of battery) and only a slow loss of charge when not in use. They’re in your cell phones, laptops, and now in your cars, but many consumers don’t understand how a rechargeable battery works.
In this brief article, we’ll explain how a lithium-ion battery works and some of the cool scientific discoveries around this amazing kind of battery.
Batteries and the Electric Car
For the longest time, the limiting factor in electric car deployment was the battery. Storing energy is difficult and has only recently caught up to the power demands we have of technology.
Internal combustion engines are really good at creating energy through combustion. The small amount of electricity needed to light the spark was negligible on an electric battery – and let’s be honest, we all run our battery out leaving the lights on! Although batteries existed in the 1970s, the range for powering a car was less than 50 miles – not nearly enough to compete in any serious fashion with the electric car.
Enter the lithium-ion battery – small and compacy, powerful and quickly charged, and not one to discharge easily. Now we’ve got a game changer in the fully electric vehicle market!
Rechargeable and Reusable
Remember how electricity works – passing electrons along atoms to generate energy? A battery uses the same principle by storing electrons on atoms inside a cell.
Most batteries work using a chemical reaction – electrical energy is converted from two compounds mixing together at a very controlled rate. A battery has at least two half-cells – an anode (where the elctrons start) and a cathode (where the electrons end up). The chemical reaction forces the electrons from the anode to the cathode across a bridge.
In a lithium-ion battery, the chemical reaction happens in a gel polymer that holds a substance that’s rich with lithium ions (if you want to know the name of the electrolytes, take a look at this Wikipedia article). When you activate the battery, the lithium ions move from the anode to the cathode, letting go of their electrons, which create electricity!
How a lithium-ion battery discharges and powers your devices. Image from HowStuffWorks
To recharge, the battery moves the lithium ions back to the anode through another chemical reaction.
Lithium-ion batteries are very good for portable devices, like cell phones, laptops, and cameras. It’s estimated that nearly 70% of the rechargeable electronics produced in Japan are made with lithium-ion batteries
Advancements in Battery Technology
We posted recently about a 3D lithium-ion battery model out of the University of Illinois Urbana-Champaign. Instead of using a 2D model of diffusion, the reseachers’ batteries are in a 3D skeleton of styrafoam. This allows for more surface area for the chemical reaction to occur, meaning that batteries hold more power and charge siginificantly faster than current models.
There has also been research into making a solid-state lithium ion battery. Currently, lithium is stored as a liquid in batteries because of how easily it moves around the half-cell. Researchers, however, have begun experiments with lithium in solid form, meaning that we can draw as much as 95% of the battery’s potential power when in use, a significant improvement over the status quo.
Fancy physics and chemistry aside, the lithium-ion battery is one powerful piece of technology.
Shifting Currents 