How electric car batteries work: cost, composition and lifespan

The electric mobility revolution has meant that there are more and more electric cars on the market and that we have many options to choose from. But one of the important things we need to consider when making this selection is the type of battery used by the car we have chosen. Not all of them are the same or offer the same characteristics. And, above all, they do not cost the same, so it is one of the main things we need to look at.

Types of electric car batteries

There are several types of batteries for electric cars on the market today. Several battery types have been discarded and are no longer offered in current electric cars. These technologies have ceased to be efficient and have been replaced by more effective batteries that offer better performance.

The most common today are lithium-ion batteries. These offer good energy density and are made up of lithium, cobalt and oxide diodes and a lithium salt electrolyte. They usually have a service life ranging from 400 to 1,200 charge cycles. The range they offer depends on their size, but today they can offer between 400 and 600 kilometres. Obviously, each model uses energy in a different way, so these figures may vary.

Another type of battery now in use is lithium iron phosphate, also known as LFP. These are used in cars that do not need as much range, since they do not have such a high energy density. They have a higher charging capacity, with up to 2,000 charge cycles.

In the case of hybrid and plug-in hybrid cars, other types of batteries can be used, since the demands of use are different and not as high. One of the most common uses nickel-metal hydride cells, which have a lower energy density than lithium-ion ones.

It is smaller and has a service life of between 300 and 500 charge cycles, which makes it very suitable for traditional hybrid cars. Plug-in hybrids usually use more efficient lithium-ion batteries.

Battery placement

Electric cars use large batteries, so they need to be placed where they do not get in the way or take up interior space. The best place to put them is the floor, where they do not get in the way and their weight helps keep the centre of gravity low. Hybrid cars, having a smaller battery, can carry it in the boot, although this reduces the space there a little.

Battery weight

The weight of the batteries varies considerably depending on their size. In compact electric cars, the battery can weigh between 200 and 500 kg, while high-end cars, which use batteries of around 75 kWh, can have batteries weighing more than 500 kg.

This means that they are heavy cars and need specific suspension elements and tyres.

When the battery of an electric car needs to be replaced

Batteries cost around 30% of the price of the vehicle, so we can say that it is the most expensive element of the car. As for battery life, in Europe a warranty of 8 years or 160,000 kilometres is offered. This means that this is the minimum time the battery will last at full performance. Normally they remain above 70% of their capacity until that point, and the loss occurs after that time.

Replacing a battery can be very costly, as we have seen, but there are manufacturers who can repair the battery, replacing the cells that have deteriorated and bringing it back to life.