It seems he associates you putting him in the crate, with you leaving - he surely knows when it's bedtime. He needs to begin to learn that he can go in the crate and actually have fun in there. Begin very slowly with him, take him for a good walk, have a play session, make sure he's tired, give him a good chew, put him in the crate with his chew - and close the door. Leave him only for a minute, then open the door again - session over. Good boy. Repeat this many times, slowly increasing the time that door is closed - while you're home. He'll soon learn how to go into his crate and actually relax when he's in there. One thing you don't want to do, is let him out when he's barking or crying. Wait til he's quiet - then let him out. Barking and crying gets nothing. Quiet gets you lots of good things.
Do give him entertainment while he's in there, tho, when you're leaving. Maybe get a kong, stuff it with peanut butter and a few small treats and freeze it. Frozen, stuffed kongs will keep dogs occupied for a long time - they can lay there and lick and lick and just be in their own little world. It gives them something to concentrate on besides wanting out!!! Frozen kongs take a long time for them to work on, and they're usually ready for a nap when they're finished. You can also stuff a kong with things like applesauce, a little canned food, bananas, kibble, broth, make up your own 'stuffing' - then freeze it. Mine LOVE peanut butter - and I always freeze them, it's a huge treat, they get so excited when they see me get them out of the freezer! He'll soon see his crate as a great place, not just as someplace boring that always means that mom is going away. Right now, it probably just feels like jail. Make it feel like his own little retreat place, someplace where he's gonna always love to go, someplace where good stuff happens, someplace where he can get away from it all, and just relax.