While crating your dog at night may help you get more sleep, depending on how long he's crated throughout the day, it could be an unhealthy solution. Dogs need time outside of the crate, or else they suffer emotionally and socially. Even a dog who normally loves his crate may not want to be forced to stay in it all night, especially if he's locked up during the daylight hours.
If your dog doesn't behave at night -- he always wants to play, or has accidents, for example -- crating him may force him to get the sleep he needs. Your dog may resist sleeping in his crate, but with training, he will get used to it. He may even come to love spending time in his crate -- he has a natural instinct to sleep in a den, and this gives him just that opportunity. Your dog may misbehave at night because he isn't getting the attention or exercise that he needs, though, and this may be because he's spending too much time in the crate as it is. If you crate your dog while you're away from home throughout the day, he comes out well-rested and ready to play. Dogs are social, physically active creatures, and he needs your attention before you turn in for the night. Letting him out of the crate and giving him more exercise opportunities during the day makes it more ethical to crate him at night, and may even eliminate the need to do so.