WARNING: THIS IS NOT FACT. I AM UNABLE TO PHYSICALLY TEST IT.
Dark energy doen't exist. It is an illusion caused by relitivity. Objects aren't just moving farther apart, spacetime is expanding. When time expands it runs faster (as observed by an observer in contracted time, say on a planet). The expansion continues so, to us, the time of an observer in space with minimal gravity is always going faster. To the said observer, the expansion of the universe is slowing down due to gravity. To us, it is speeding up because we live in "slower time" and thiers is always speeding up. If you were a few kilometers from a black hole's event horizon, then the expansion would seem infinite.