Don’t Do This at Home: Watch Electric Vehicle Battery Abuse

(Al-Bail 24): It’s just a matter of preparation. China will dominate parts of the auto market in the future, although we are nowhere near that yet.

But China already has more influence today than most people realise. The reason lies in the raw materials and in the production of batteries for our electric cars.

BYD is the largest auto manufacturer in China, and when we talk about batteries only, BYD and CATL are among the dominant companies.

On a broader assignment in China, Elbil24 made the trip to Chongqin, among other things, to take a closer look at one of BYD’s battery factories. There we also got to see the famous penetration test, which is part of making electric cars safer. To put a city like Chongqing into perspective, this is a city with a population three times the size of Norway. However, Chinese automakers are sitting back and watching what happens in the electric vehicle market in Norway.

divided into two parts

The battery factory in Chongqin is divided into two factories, called Phase I and Phase II. Strictly speaking, one plant was built before the other in 2020 and 2021 respectively, and together these two plants have a capacity of 20 GWh and 15 GWh respectively, 35 GWh in total. The batteries in question are of course the new Blade battery for which BYD has gradually become known.

Tesla and Toyota are among the companies that have signed an agreement to buy such batteries from BYD, and it is expected that, among other things, the upcoming bZ3X will get them – also here in Europe.

The defining characteristic of the Blade Battery is that – aside from the form factor – the batteries are LFP batteries. As of today, there are a few models of electric vehicles that use LFP batteries, while the most prevalent are still typical NMC batteries, the stock being nickel (N), magnesium (M) and cobalt (C).

Among other things, LFP (Lithium Iron Phosphate) batteries don’t contain cobalt at all, which is one of the main reasons they’re interesting, but another point that makes them very interesting is safety.

So BYD published tests showing the difference between a typical NMC battery cell and its blade cells in what is called a penetration test, and we were able to participate in such a test.

The new Tesla battery is very impressive

Simply put, an electric car battery consists of several batteries called cells. Each of these battery cells, which is actually a separate standalone battery, is connected with many similar cells to form a larger battery pack.

Safety is important

Since they are installed in the vehicle that will travel at high speeds, it is very important to ensure the safety of these batteries, which after all contain large amounts of energy.

In order to test the fire and explosion risk of batteries, BYD has what’s called a penetration test, in which a thick needle is passed through a fully charged battery cell. Testing is done with an ordinary NMC battery, and on one of its LFP batteries. The difference is surprising to say the least.

During testing, what happens to the two batteries is also measured, primarily the short circuit current which is hardly present with the Blade battery.

See the physical exam here:

When an NMC battery is punctured, an explosion officially occurs. The battery explodes, catches fire and burns for a long time after that. This is the typical risk you want to avoid with electric cars, which contain not just one cell, but several hundred. When the same drill is performed on a Blade Cell, almost nothing happens, which is the outcome sought for safety reasons.

Technically, the voltage in the NMC battery drops to 0 volts within three seconds, and the temperature rises almost instantly to about 600 degrees Celsius.

In a Blade Battery, the voltage drops to 0.03V in five minutes, while the temperature never exceeds 60°C.

This means a huge difference in risk in the event of an accident. When we then ask BYD if this is a result of LFP battery technology in general, or the Blade battery in particular, they are so honest they say both. LFP batteries should be much easier to handle, but the way BYD packaged them is an added factor.

SEE MORE PHOTOS FROM BATTERY FACTORY:

The actual way to make an NMC battery and an LFP battery is basically not much different. On the other hand, the BYD Blade cell has a special form factor, being almost a meter long. BYD therefore places the cells across the entire width of the vehicle, and in the new platform it has developed, the cells are packed in what is called a cell-to-body structure, without packing the cells into a battery pack first (cell-to-pack), which is then stacked at the bottom from the car.

During production – before it becomes a ready cell – the method is very similar. They are chips that are drawn on the anode or cathode material, then added with a separator, which is actually an insulating material, and in the blade cell there are 17 of these layers in the final cell.

This brings the capacity to 138.5 Ah, converted to 0.44 kWh. The NMC cell used in the test has a similar capacity of 130 amps, which equals 0.48 kWh.

And when we then know that there are a few hundred of these cells in a well-equipped electric vehicle, that also tells us something about the potential energy that will be released in an accident.

For BYD, it may seem that they have now found the formula for what they want to put in their cars in the future.

The batteries are also called 3C batteries, which determine the charging and discharging speed of the batteries. It remains uncertain whether the vehicle manufacturer would allow the software to use that speed, even if the cells were capable of performing at that level. They can be reduced by the battery software, both in terms of performance in use and while charging.

As is well known, lower energy input and output increases the life of these batteries, which in turn can have an impact on how long the manufacturer chooses to give the final battery in the vehicle. The standard today is which comes first after 8 years or 160,000 km.

Some manufacturers offer a longer warranty, for example, for frequent visits to one of their service points.

But development is proceeding at a furious pace. We’ve already seen examples of cars that can be recharged with a new 400 kilometers in ten minutes. Then it smells burnt, and it certainly doesn’t stop there, so stay tuned.

Travel and accommodation costs for preparing this report were fully or partially covered by the importer. Read more here.