The average lifespan of a car is around 14 years. A recent study reveals that a Nissan Leaf with the original 24 kWh battery pack loses about 20 per cent of its capacity on average over five years so it's not inconceivable that many will outlast a typical petrol or diesel car without needing a replacement battery. If you do want to replace the battery in an EV, it will cost around £5000 depending on the model.