One of the biggest concerns for car owners as the world turns to electric vehicles (EVs) is what happens to batteries. According to Autocar , various studies have been conducted in this field that can be helpful.

 For example, during a taxi test at Gatwick Airport, five Tesla S 90D electric vehicles were able to cover 1.5 million miles, each traveling about 300,000 kilometers over a three-year period. 

After that, the batteries were in the healthy state (SoH) of about 82%, which seems very impressive. 

The Tesla Model S was initially offered with an eight-year warranty and unlimited mileage; But the warranty of the Model S in 2017 was reduced to 150,000 miles (240,000 kilometers) or eight years of operation, and with a health condition of 70%.

 If the battery of an electric car becomes so weak that the car’s mileage reaches less than 405 km in less than 150,000 miles or eight years, Tesla will replace the battery of the Model S or Model X customers.

Mercedes-Benz, on the other hand, offers electric car batteries with a 100,000-mile or eight-year warranty, and so does the Jaguar I-Pace. So it is clear that owners of second-hand electric vehicles will have problems with long-term battery life.

Electric car batteries are known to break down faster in the first year or two.

 Battery health decreased by about 8% in 100,000 miles (160,000 km) in the first year of the Gatwick test program; But then the devastation was accompanied by an increase of almost 5% per year (driving 100,000 miles per year).

 At this speed, electric vehicles could easily cover 500,000 miles before reaching 70% health. This amount is more than three times the guaranteed performance.

How to prevent an electric car battery from being damaged

First, let’s define a technical term: knee point. This is the point at which the battery (after that) is rapidly damaged; Which is exactly what every battery and vehicle manufacturer is trying to prevent. 

This phenomenon has been extensively studied in recent years. Assuming that the car battery is well made (without defects), if more pressure is applied to the battery during operation, more knee points are created.

Elbow points in battery health occur through overcharging (which raises the temperature of the battery too much) and overcharging and overcharging. 

Charging the battery from 10% or more to a charge state (SoC) of less than 90% most of the time and using low-charge fast charging will help ensure longer battery life. Resting the battery once a week for a few hours in relatively low SoC conditions will also help extend its life. 

Battery health status (SoH) is an absolute measure and will become an important factor in battery sales in the future. 

Electric vehicle drivers focus on SoC; But the real measure that is economically important is the SoH; Because it tells the driver if he has enough charge to reach his destination or not.

What happens to the battery after the SoH drops below 70%?

A battery with a SoH of about 70% may no longer be suitable for use in an electric vehicle; But in a power storage system equipped with a second-hand battery (BESS) it will be very useful for a few years (at least five years) to reach the SoH of about 50%. 

Of course, the battery is no longer commercially useful at that time, because it has reached the industrial kneeling point.

The market for energy storage systems is on the verge of dramatic change and is growing just like other technologies such as computing power, network capacity and data storage. 

Australia’s Hornsdale power storage complex, for example, was completed with a capacity of 150 MW / 194 MW and became the world’s largest BESS in three years. 

Last year, the Gateway Energy Storage Complex in California surpassed the Hornsdale Complex with a massive 230 MWh storage capacity.

However, the capacity of Tesla’s new plant in Moss Landing, California, at 730 MWh, is almost double that of previous complexes. Vistra Energy plans to open a very large energy storage complex in Moss Landing with plans to reach a capacity of 1,500 MW / 6,000 MWh, which was approved in October. 

It is BESS that is revolutionizing the energy market and allowing energy to be stored by renewable sources of wind, solar and water. The dramatic increase in the size and number of large energy storage complexes reflects the growth of the small BESS home-based business, the most important of which are Tesla Power and Powervault in the UK.

Most energy storage complexes are built using new batteries; But more use second-hand batteries in electric vehicles. 

Tesla has reported that its batteries will last a mile or more (probably up to about 70% SoH); But it has not yet mentioned the use of second-hand batteries in BESS or anything else.

Second-hand batteries cost much less than new batteries; Despite the shorter life of second-hand batteries, their return on investment will be higher economically and they are economically attractive to investors and companies.

A battery with a SoH of about 75% will last half the life of a new battery, but it costs far less than half the purchase price of a new battery. 

This will be exactly the missing point of Tesla batteries; Because they are not yet fully recycled and can no longer be used in electric road vehicles.