Experts are right to be skeptical that it's possible with current gen tech. As usual, Musk is probably extrapolating charge speeds to when the truck will be finally delivered, which is in what, 2020?
No, the two have nothing to do with each other. The Tesla Semi charges slower than the model S does already- it takes roughly the same time to charge a battery regardless of how large it is. That Bloomberg article is not talking about the battery itself, its talking about the charger- the wires hooking up to the battery.
Before Tesla and Panasonic joined forces to mass produce the batteries, there were many many rumors that samsung was in negotiation with tesla to supply the batteries. I wonder of Tesla will look into working with samsung.