How do you label

Time = energy • power

First of all, that equation is not correct, which may be the reason

that you're having trouble assigning units to the quantities.

Power is defined as [energy / time], so [Energy] = [ power x time ],

and

[Time] = [ energy / power ].

Unit-wise, these equations are correct just as they appear here,

with no proportionality constants or conversion factors, when ...

[ Power ] = watts

[ Energy ] = joules

[ Time ] = seconds.