An EV battery is typically made up of thousands of rechargeable lithium-ion cells connected together to form the battery pack. Lithium-ion cells are the most popular because of their cost efficiency, offering the most optimal trade-off between energy storage capacity and price.
In general, a battery cell is made up of an anode, cathode, separator and electrolyte which are packaged into an aluminium case. The positive anode tends to be made up of graphite which is then coated in copper foil giving the distinctive reddish-brown color.
EV batteries are made from a combination of raw materials. ‘Base’ metals such as aluminium, copper and iron are important ingredients, but the most expensive materials are ‘precious’ metals such as cobalt, nickel and manganese, along with elements such as graphite and lithium.
There are three basic types of battery cells used in electric vehicles: cylindrical cells, prismatic cells, and pouch cells. Coin cells also exist, although these are currently restricted to research and development for testing purposes and haven’t been used in EVs commercially. 1. Cylindrical cells
Each cell consists of the active electrode materials – the anode and the cathode – which perform the electrochemical energy storage function of the battery.
The main container typically uses a mix of aluminium or steel, and also plastic. The individual battery cells within the module need protection from heat and vibration, so a number of resins are used to provide mechanical reinforcement to the cells within the module: Demounted battery from electric car Nissan Leaf.