At the heart of an electric vehicle is a crucial component – the battery. Although it looks like a single unit under the floor of most electric cars, it’s actually a carefully engineered pack containing hundreds, sometimes thousands, of individual battery cells all working together to store and deliver power. Understanding how this system works reveals just how much technical ingenuity is packed into the average EV.
The most common batteries used today are lithium-ion, chosen for their high energy density – the amount of energy they can store in a relatively small space – and their ability to retain that energy over thousands of charging cycles. Each cell contains a positive electrode (cathode), a negative electrode (anode), and a liquid electrolyte that allows lithium ions to move between them. When the battery is charging, lithium ions travel from cathode to anode, storing energy. When the car is driving, the ions flow back to the cathode, releasing energy that powers the electric motor and turns the wheels.
A key area of development lies in the anode. Traditionally made from graphite, anodes are now being re-engineered using materials like silicon, which can store far more energy. The challenge is that silicon expands as it charges, which risks damaging the battery. But with newer technologies and materials, manufacturers are getting closer to making high-capacity silicon anodes safe and commercially viable – a change that could dramatically extend the range of electric vehicles.
Batteries aren’t just a power source – a network of sensors and electronics continuously monitors the battery’s temperature, voltage, and charge level. This helps maintain safe and efficient operation across all driving conditions, and many batteries are liquid-cooled to prevent overheating, ensuring longevity and consistent performance.
Charging an electric car works in reverse. When you plug into a charger electricity flows back into the battery, moving the lithium ions back to their charged state. Although fast chargers can significantly speed up the process by delivering higher voltage, with some models reaching 80% charge in as little as 30 to 45 minutes, charging times vary depending on the size of the battery, the power of the charger, and the ambient temperature.
Battery capacity – measured in kilowatt-hours (kWh) – determines how much energy a battery can store, and in turn, how far the car can travel on a single charge. A typical EV might have a battery capacity of 40 to 100 kWh, offering a real-world range of 150 to over 300 miles. Larger batteries can take longer to charge and add to the cost of the vehicle, but they provide peace of mind for longer journeys.
Over time, all batteries degrade slightly, meaning they hold a little less charge each year. But modern EVs are engineered to retain most of their capacity for at least a decade. Even after their useful life in a car ends, batteries can be repurposed for energy storage in homes or businesses.
Behind the scenes, progress continues. Solid-state batteries – a new generation of battery technology – could soon replace the liquid electrolyte with a solid one. This change promises to make batteries smaller, safer, and faster to charge, opening the door to electric vehicles with even greater range and performance. Although not yet ready for mass production, they represent one of the most promising frontiers in the evolution of EV technology.