OK, I did some calculations based on:

* a 5,000 km electric range. * 40MW continuous power requirement for a 21.5 knot cruise speed[1] for a 14000 teu container vessel: * the size and weight capacity for the batteries being the same as the fuel capacity for a 14000 teu container vessel (taking the upper figure from [2]) * the battery pack having similar gravimetric (weight) and volumetric(size) energy density as this a modern Chinese NMC EV pack[3]

The short version is that the battery vessel would require about 25,000 tonnes of batteries for a 5,000km range under those assumptions, which compares to the current fuel capacity of approximately 13,000 tonnes. Volumetrically, it's even closer - about 17,000 cubic metres, compared to about 13,000 for the bunker fuel.

Furthermore, it's worth considering just how much cargo the ship carries. One teu corresponds to about 33 cubic metres of cargo space (not counting the space taken up by the walls of the container), so the ship can carry about 462,000 cubic metres of cargo. So the additional space required to carry an additional 3,500-odd cubic metres of batteries corresponds to only about 0.8% of the ship's total cargo-carrying capacity.

I was surprised at just how doable this is, to be honest. What threw me is just how much bunker fuel ships can carry; if I'm doing the sums right, a ship like this can carry enough fuel to circumnavigate the globe a couple of times over. It may well make economic sense but it's not really necessary to have that kind of range to operate the ship safely.

[1]https://www.man-es.com/docs/default-source/marine/tools/prop... [2]https://www.freightwaves.com/news/how-many-gallons-of-fuel-d... [3]https://www.batterydesign.net/zeekr-140kwh-catl-qilin/