I actually assumed that was part of the impetus for creating their own ship – standard cargo ships probably aren't well-suited to the job and simultaneously are a bit concerned about transporting such cargo.

Specialized car carriers are fairly common. Maybe they added some changes to make this one especially well suited for EVs, like modified fire suppression systems. But it may well be a standard ro-ro ship with an LNG engine.

It would be cool to pull charge off the batteries to power the ship.

I estimate that all those batteries would get that ship at most 20% of the way across the Pacific.

The ship runs on LNG, which is probably cleaner than charging the cars in China and using that for energy, given China's grid mix.

It seems to already use some batteries, but not sure for what:

“the new ship includes BYD box-type battery packs and shaft-belt generators for the first time”

Salt water spray is not great for vehicles in general, even ignoring batteries. Wonder what the heck they were thinking.

You could say the same thing about a refined fuel tanker.

Realistically, what is the concern for EV batteries? They already make up a pretty substantial amount of market chair in the US, and yet I don’t hear stories about EV’s being more dangerous or more prone to fires or anything. The only time you ever really see an EV burning is one that was in an accident, and guess what, gas cars also blow up when they’re in an accident sometimes

In terms of fire risk, ten thousand gasoline cars are worse. And they have to be fueled because the cars are driven in and out of the carrier.

EV fires are harder to put out, but in every other way this isn't different from any other car carrier