Cool, but I don’t see the real benefit. Electronic trucks already work quite well, start at around 150k (vs. 150k for a retrofitted e trailer), and are afaik mostly limited by the charging infrastructure. If you now add a an electronic trailer to your diesel truck, you now also have to care about charging.
Yes, in Europe the legally required rest periods can already be used for efficient charging, but this is not an benefiting exclusiv to the trailers, but for general electronic trucking.
I suppose the trailer has a lot of space for solar panels on top, which the tractor does not. But those could be connected to the tractor rather than the trailer. Of course
Charging time. A truck/driver doesnt remain stopped. It drops a trailer and picks up another. And a truck needs charging on the open road where there just are not any charging stations. But a trailer remains parked at a loading bay for hours, a commercial facility where installing chargers makes sense. A trailer therefore has more oppertunity to charge than a truck.
And if a company wanted to, parking a trailer to let it charge is far cheaper than paying a truck/driver to sit around.