Lithium-ion battery operation
The principle behind lithium-ion batteries is to cycle electrons by creating a potential difference between two electrodes, one negative and the other positive, which are immersed in a conductive ionic liquid called an electrolyte. When the battery powers the device, the electrons accumulated in the negative electrode are released to the positive electrode through an external circuit: this is the discharge phase. Instead, when the battery charges, the energy provided by the charger sends electrons from the positive terminal back to the negative terminal.
Different battery types vary by ion type, electrode material and associated electrolyte. For example, the 12-volt lead-acid battery traditionally used to power the starter of an internal combustion engine vehicle relies on an electrolyte containing lead ions and lead-based electrodes. As for the lithium-ion battery, it uses lithium ions (Li+): hence the name of the technology.
Lithium-ion batteries, such as those found in cars such as the ZOE, are designed as an assembly of individual battery cells (batteries) that are interconnected and monitored by dedicated electronic circuits. The number of cells, the size of each cell, and how they are arranged determine the voltage the cell provides and its capacity, the amount of charge it can store. This is usually expressed in watt-hours (Wh) or kilowatt-hours (kWh) in the automotive industry.
