Degradation of Batteries in Electric Cars: Duration and Factors

If you are thinking of buying an electric car, there are many questions that will be around your head before doing so or deciding on one of these models or another. For example, your battery. One of the main unknowns that we must reveal is why degradation of batteries in electric cars occurs , what are the most common factors, how we can avoid it or how it will affect us.



If you have an electric car or plan to have it, you should consider how long the battery will last since it is a primary issue before deciding. In general, the battery coverage of an electric car by the warranty is usually eight years but this varies depending on the model, the manufacturer or the country. Be that as it may, let’s assume that there are reasons that make it degrade. But the question is: why does an electric car battery break down and how would it affect us when choosing?

electric-cars-battery

Battery degradation

The degradation of the battery of an electric car is a process that is being carried out little by little and that, as its own name indicates, makes the amount of energy that it can store less and less. Contrary to what you may think at first, the degradation of the battery in a vehicle of this type is not the same as its range. In the first case, it is about how much energy we can get with that battery (in kWh) and in the second case it would be about how much distance we can travel with those kWhs that offers us autonomy but in which there are also all kinds of factors that We already know how the load on the vehicle, the temperature, the topography of the road or even how we are accustomed to driving regularly.

The battery is usually one of the main elements that “suffers” more in a car of this type and is usually reduced as we use it. The autonomy of the batteries usually lasts, approximately, for about eight years in an optimal state. Or, at least, it is what most manufacturers guarantee: eight years of optimal autonomy and about fifteen or twenty years of average life although this may depend on countless factors or how we “treat” the battery of our electric car. Generally, a battery is considered to be in good condition when it maintains 80% of the original capacity.

recargar coche electrico

The degradation of the batteries is not linear throughout the lifetime, nor is it proportional to the use we make of cars. That is to say, by using an electric car more, the battery of the car will not be damaged before in one with less use. Nor is it maintained over time: it is normally stable in the first three or four years and from the fifth the degradation of the batteries begins to accelerate. It is estimated that at six and a half or seven years, batteries tend to be around 90% of their initial capacity, losing faster in successive years.

The batteries of electric cars are degraded, yes, but the best way to avoid it or extend its useful life is to follow a series of tips and care quite simple such as taking care of charging cycles, avoiding exposure to excessive heat, not leaving the vehicle charging more time than necessary in case of very hot or avoid driving in reserve so that this useful life is extended a little more than usual.

Differences between models

Although we can analyze why the battery of an electric car degrades, the motives do not always apply in the same percentage to all vehicles on the market. In 2019, the Geotab company carried out a study with information on 6,300 electric vehicles of more than 20 different models and it is interesting to check the great differences between some of the models analyzed.

The average degradation of the batteries is 2.3% capacity each year although the first years remain much more stable and the loss soars from the fourth or fifth. But there are not only differences between years (or the use we give) but between concrete models, for example.

In the case of the Geotab study, we can verify that a Tesla Model S suffers a degradation of the batteries of 5.7% in three years while a Nissan LEAF reaches a degradation of its battery of 11.6% in the same period . In the case of the LEAF model, it would do so much faster, as we can see in the following graphic. For its part, a KIA Soul EV vehicle would only lose 2% in thirty months,

Tesla vs Nissan - Degradacion de las baterias

The study also emphasizes the difference in electric cars with respect to plug-in hybrid cars. The latter see how the degradation of the batteries is much lower since they have a lower charging power although it also influences that these are vehicles that can be charged less frequently than the previous ones. Following the analysis, an Audi A3 e-tron would not lose even 1% of its battery capacity in two and a half years. A Toyota Prius Prime, for example, would only lose 3.3% of the battery in this period. Figures far from more than 10% of the model mentioned above in a similar time.

Toyota

Factors that influence degradation

Although it is inevitable, in most cases, there are factors that influence.

Fast charging

One of the main factors that most “damage” do a battery is the rapid charge of it. According to the mentioned study, the frequent load of the vehicle does not affect the loss of capacity but it can be accentuated in the case of using fast chargers that use direct current for the load. With fast charging we would lose 10% in five years and without them the battery would lose less than 2% of its capacity in the same period of time. If the fast charges are made once, twice or three times a month we would achieve a degradation of the batteries greater than 8%.

carga rápida coche eléctrico

Battery level

Beyond how to charge it, it is also important when to load the vehicle. According to experts, it is considered optimal that the battery is always maintained between 20% of the charge and 80% and that we do not wait for a complete discharge. At the ends of the battery, the car could not deliver maximum power and could change the way in which we drive or in which the vehicle responds so this is not only important for the health of the battery but for the “safety “Of the car itself.

cargar coche electrico baterías

Mileage

Far from what one might think, mileage has little to do with the degradation of the battery of an electric car. It will not influence you to do more or less kilometers. According to the Geotab study, there are no significant differences between vehicles that exceed 25,000 kilometers per year and vehicles that travel less than 8,000. Of course, it should be borne in mind that greater use or heavy use can lead to a greater number of fast charges and this would affect the degradation of the battery.

Degradación de las baterías: uso

High temperatures

One of the main problems of batteries in electric cars are especially hot climates. In the case of exposure to excessive heat for several days a year we will have a much greater degradation than in vehicles that are in much warmer climates.

Tips to avoid it

If you have decided to buy an electric car or you already have one, we can summarize all the previous points in a few tips that you should follow and whose fulfillment will not entail any extraordinary effort. The battery will end up degrading, yes, but it will be much better if we slow down the process.

  • Maintain, as we say, the battery always between 20% and 80% of the total maximum capacity. Only charge it in full in case you need it for a very long trip but do not keep it parked with loads below 20% or with a total load.
  • Avoid fast charging. If you avoid this type of load, you will see that the degradation is much slower. Try to plan ahead or use apps for electric cars where you will have the charging points located on your journey.
  • Beware of extreme temperatures … You cannot avoid it getting very hot at certain times but you can choose where you park, leave the vehicle in covered parking lots or in the shade and not in the sun.

Reused batteries

Once the vehicle has lowered its battery capacity more than 80%, it is not interesting that we continue to use it to give it life. But that battery is not dead at all, it still has a large capacity and can be used in other uses. Some manufacturers are already investigating how to use batteries once they are not useful for cars and thus prevent them from becoming waste, for example.

Currently, car companies such as Toyota, Nissan, Renault or BMW are already collaborating with companies and suppliers to contribute to the energy sector with these batteries that are no longer going to be used. For example, some of the new uses for reused batteries is to provide energy to buildings and homes. A battery that is not suitable for a car can be used to give light in an apartment for a whole day in Spain. They are also being planned as options for supplying energy for public lighting, such as recycling for new uses in electric vehicles or even for lighting stadiums : The Johan Cruyff Arena in the Netherlands uses reused Nissan Leaf batteries together with 4,200 solar panels that make it supplied enough energy

Other breakdowns and care

Beyond why batteries are degraded in an electric car, you should consider some keys or issues in the maintenance of an electric car if you are thinking of buying a new one. It will be more affordable if you are worried about continuous visits to the workshop but that does not mean that it requires care and maintenance:

  • The coolant of the batteries will be specific for this type of vehicles and should be changed when indicated, according to the model or the manufacturer, although it is normal that around 80,000 kilometers for the first change.
  • The brakes will suffer less in a vehicle of these conditions. Why? Electric cars take advantage of a regenerative braking system that will make the pads wear less and have to be replaced less frequently than in a normal car. Of course, you must change them.
  • The tires will need the same maintenance.