When to replace the expensive battery pack?

The short answer: There will be no need for that! The car batteries are designed to last years longer than the average life of an electric car.

The first question I often get as an EV salesperson is; “How much does it cost to replace the battery pack?” Often triggered by the high prices shown in the (social) media, but also by the experience the customer has with their mobile phone battery or laptop battery which are losing capacity rather quick.
The answer I give to the customer is simple: “There will be no need to replace the battery pack during the lifetime of the car.”

The car batteries are designed to last years longer than the average life of an electric car. Electric car batteries are expected to last between 15-20 years before needing replacement, provided that you treat your battery with care. Since the average car lasts about 12 years, your electric car’s battery will likely last longer than the car itself.

Degradation of an Electric Car Battery

Overtime the batteries will degrade, but they will still hold enough power. To put it more precise, after 10 years of use the battery pack will still have an estimated remaining capacity of at least 93%. (… after ten years! …)
So, if you have a car with a range of 501 km, then after 10 years that range will be degraded to 465 km. That difference is hardly noticeable on your daily commutes.

I will not bore you with technical data. (I have added some weblinks for you to read the details.) However, it is worth mentioning that Electrical Cars have a Battery Management System (BMS) while your mobile phone or laptop does not. That system will control how to charge and discharge the battery to prolong its lifetime.

Also, a new EV car has a kind of ‘overcapacity’ in the battery that will not be used (often) at the start of the battery lifespan. Initially, the BMS will not use the full battery capacity. At the time the battery degrades over the years, the BMS will use more and more of the full capacity. Therefore, you will not notice degradation for many years.
This is the so-called grace capacity. For detailed information please read this link.

In case of malfunctioning

As with all technical machines, a malfunction can occur. This will most probably be noticeable within the warranty period, so repairing costs will not be an issue for the customer.

Most people think that the entire battery pack needs to be replaced in case of a malfunctioning. But that is not true in all cases. Specialized technicians can localize which part of the battery pack is not functioning correctly, and then only that part is replaced. For example, a malfunctioning battery-cell.

I always like to compare it with a gasoline car. If you have a gasoline car and the sparkplug is defect, you do not replace the entire engine but only the sparkplug. It is the same with battery packs. You just replace the faulty part, not the entire battery pack. However, in these rare cases, the repair costs can be substantial.

You can help to prolong the battery life

As you will notice, all text and weblinks will give you estimates. Battery lifespan expectation is very dependable on how the battery is used (or mis-used). If you take good care for the battery, it will last a lot longer. I have written an article <Sustain EV car battery health> with tips to prolong the battery lifespan.

Battery End-Of-Life

As stated before, the battery pack will most likely outlive the lifespan of the car. So, what happens to the battery?
If the EV battery pack eventually needs to be taken out, due to replacement or recycling of the car, the battery can have a second life.

When an EV battery completes its service life on the road, it can still retain approximately 80% of its storage capacity. That is not good enough for Electric Car, but more than sufficient for other purposes.

An EV battery can embark on a second life as a stationary power source, serving as grid-connected storage. For example, after remanufacturing, the battery pack can perfectly be re-used as a storage battery in combination with solar panels.

After it’s second life, it is possible to recycle 95% of the materials used in the battery. This recycling process is in the early stages, but the industry will soon pick this up on a large scale. On Curacao, this recycling process is not available (yet) but I suspect that in the future it will be profitable to export used batteries for recycling.