Whether beans need to be blanched before freezing them can be debated.
I have tried three ways, and here is my experience:
1) Freeze without blanching
2) Blanch lightly and freeze
3) Freeze when fully cooked.
1) Freeze without blanching
I washed the beans well and dried them on a towel before freezing them.
This worked out pretty well, but I noticed that I had to cook the beans for a very long time. It wasn't the same amount of time as when you cook them fresh. I'd say they had to be cooked almost twice as long, otherwise they became a bit tough to eat.
2) Blanch lightly and freeze
This appears to be the best method, in my honest opinon.
Here too, I noticed I had to still cook them for quite a long time.
3) Freeze when fully cooked.
This works well when you're usually in a hurry to make dinner, or when you like your vegetables cooked very well.
I've been using the second method for a few years now, after trying all three methods.