Electric Vehicle Batteries Explained

Electric vehicles are rapidly transforming the automotive industry and at the heart of this revolution lies their battery technology. EV batteries are essential for powering electric motors, determining range and influencing the overall performance and cost of an electric car.

Types of EV Batteries

Most modern EVs use lithium-ion (Li-ion) batteries, the same technology found in smartphones and laptops. These batteries are preferred due to their high energy density, relatively long lifespan and ability to recharge quickly. Other types of EV batteries include nickel-metal hydride (NiMH) batteries, commonly found in hybrid vehicles and solid-state batteries, an emerging technology promising greater energy density and faster charging times.

How EV Batteries Work

EV batteries store electricity in chemical form and release it as electrical energy when needed. A lithium-ion battery consists of cells grouped into modules, which together form a battery pack. Each cell contains a cathode (positive electrode), anode (negative electrode) and an electrolyte that encourages ion movement. When charging, lithium ions move from the cathode to the anode, storing energy. When discharging (powering the vehicle), the process reverses and the stored energy is converted into electricity.

Battery Capacity and Range

The capacity of an EV battery is measured in kilowatt-hours (kWh), which indicates how much energy the battery can store. Higher kWh ratings generally mean longer driving ranges. For instance, a 40 kWh battery may provide a range of around 150 miles, whereas a 100 kWh battery can exceed 300 miles. However, factors like driving habits, temperature and terrain impact the actual range.

Charging and Lifespan

EV batteries can be charged at home chargers, public charging stations, or high-speed DC fast chargers. Charging times vary based on the power source, with Level 1 chargers taking several hours, Level 2 chargers reducing that to a few hours and DC fast chargers providing up to 80% charge in under an hour.

Battery longevity is a key concern, with most EV manufacturers offering warranties of 8–10 years or 100,000 miles. Over time, battery capacity declines due to charge cycles and environmental factors, but advances in battery management systems (BMS) help optimise performance and extend lifespan.

Researchers are developing next-generation batteries, such as solid-state batteries and lithium-sulfur batteries, which could offer even greater efficiency, safety and durability. As technology advances, EVs will continue to improve, making electric mobility more sustainable and practical for everyday use.