Lithium-ion batteries are currently the most common type of cells powering electric cars. While the name is familiar, the technology behind it is not. If you're wondering what powers electric cars, here are all the answers. We explain what lithium-ion batteries for electric cars are, how long they last and how to make sure they last as long as possible.
Lithium-ion batteries for electric cars - types
Electric-powered vehicles use cells called batteries or rechargeable batteries. Although these terms are used interchangeably, the differences between them should first be clarified.
Electric car battery - what is it?
Batteries, like rechargeable batteries, are galvanic cells that store and release electrical energy. The difference between the two is that they can be recharged repeatedly - energy replenishment is only possible with the latter. Consequently, the cells used in cars are actually batteries. However, the common use of the term 'electric car battery' makes it interchangeable with the words 'battery' and 'cell' in this article.
Lithium-ion battery types
Lithium-ion batteries for electric cars, on the other hand, is an umbrella term for five sub-types of cells that use different elements to operate. What they all have in common is the structure and the current conductor used. Lithium-ion batteries for cars or electronic equipment have two electrodes - an anode and a cathode. The former stores the current, while the latter is used to release it.
In order for the stored electrical energy to flow between them, a conductor is required. This is the electrolyte, a substance that is a mixture of lithium with one of five elements - cobalt, manganese, nickel, titanium or vanadium. The electrical conductivity itself takes place via ions.
How do lithium-ion batteries work in electric cars?
Batteries for electric cars are designed to provide enough capacity to power vehicles that sometimes weigh several tonnes. As a single cell would not be able to do this, many of them are fitted, usually more than 20, and what is more, each of them is capable of storing a greater charge than other battery types. As a result, it is possible to construct a battery for an electric car with sufficient capacity and, at the same time, less weight and volume than would be the case with other types of cells.
The battery for the electric car is also easy to use. One advantage is that it can be recharged when a certain amount of energy has been stored. It works best when the charge fluctuates between 20-80%. Unlike nickel-hydride or nickel-cadmium cells, it does not need to be fully discharged so that it does not lose capacity.
This does not mean, of course, that lithium-ion electric batteries do not degrade over time. They too experience a gradual decrease in capacity, known as the memory effect. However, it can be reduced by charging the battery properly and not overheating it.
Factors that affect the service life of lithium-ion batteries
The lithium-ion battery must be charged at the correct rate. Batteries for "electrics" are degraded by, among other things, topping up too quickly. If this is not necessary, it is better to avoid using fast chargers. The condition of the battery is also negatively affected by leading it to full discharge and charging it to 100%.
The lower capacity of electric car batteries is also affected by temperature. It is therefore worth ensuring that the cell is adequately cooled. This can be done in actively cooled batteries. The coolant distributed between the cells must therefore be replenished regularly.
This is worth bearing in mind when considering how much an electric car battery costs. In this way, people who have a second-hand electric car or one that no longer has a warranty replacement can extend the life of an expensive cell.
There are also factors that cannot be influenced. The battery of an electric vehicle degrades through use. There is a simple rule of thumb: the more intensive the use, the more frequent the charging, and thus the faster the capacity drops. What is more, even new batteries for electric cars lose capacity if they are not used for a long time.
How long does a lithium-ion battery charge in an electric car?
The charging time for an electric car battery depends on the charging speed provided by the manufacturer, the capacity of the battery and the power source used. A fast charger can top up a cell in as little as half an hour. Public chargers, depending on their power, usually need between three and six hours to do so.
A similar charging time to that at a filling station can be achieved using a home charger, which can be purchased for many models of 'electrics'. The car can also be charged from a standard socket. In this case, however, the charging time may be several hours.
Types of charging stations for lithium-ion batteries
Lithium-ion batteries for electric cars can be charged at stations of varying power. Slow charging stations typically have a power output of 3-11 kW and can take up to around six hours to charge. Charging stations with a power output of 11-22 kW are places with an average top-up time. A car can typically spend 3 or 4 hours at such a location. The fastest chargers have a power output of more than 50 kW, allowing the car to leave the station after just 30 minutes.
Lithium-ion batteries for the car are an example of how technology that has been known for years can be used in a completely new way. Efficient and long-lasting cells now account for the lion's share of electric cars' energy sources. However, their pain point remains the long charging time. If this problem is solved, it is possible that in future, topping up a car's power supply will be as quick as pouring in fuel.
