03.1 What is a lithium-ion battery?
Lithium-ion batteries power electric vehicles (& lots of other items we use daily)
Lithium-ion batteries power our world & are being increasingly used to decarbonise our lives, transport & energy storage.
A lithium-ion battery is a rechargeable battery cell, containing the following parts:
Depending on the application, lithium-ion batteries come in a range of form types. A cylindrical cell may be used in an electric power tool, a pouch cell in your mobile phone, a prismatic cell in a battery storage system & blade cell in an electric car.
All form types are used in electric vehicles.
How do lithium ion battery cells work?
Like all batteries, lithium ion battery cells contain two electrodes; the cathode (positive) & anode (negative). The anode is made from carbon, primarily graphite, & the cathode from metal oxides, including lithium.
Lithium ions move between the electrodes through an electrolyte, creating an electric current through the conversion of chemical energy to electrical energy. A very thin porous separator sits between the cathode & anode.
They can be repeatedly charged and discharged through many hundreds or thousands of cycles, and are 'energy dense', meaning they can hold an 'enormous amount of power in a very small space' (thanks to our friend Professor Paul Christensen for that quote!). This makes them perfect for use in a huge range of applications &, to quote Professor Paul again, 'you're never more than four feet away from a lithium-ion battery'.
Later, we look at thermal runaway, which may happen due to a short circuit in a battery cell & is how electric vehicle lithium-ion traction battery fires start.
What's the difference between a lithium-ion battery & a lithium battery?
There's some confusion online about lithium-ION batteries vs lithium batteries, especially around whether water can be used on a lithium-ion battery to extinguish a fire. So what's the difference?
Lithium-ION battery: Rechargeable, known as a secondary battery. Does not contain lithium metal, just lithium in ionic form, therefore is perfectly safe to use water.
Lithium battery: Not rechargeable, single use only, known as a primary battery. Contains lithium metal which can react violently upon contact with water.