You are right it isn't going to be a contest putting a 10 lb toy dachshund up against against a monster 30+ plus pound Badger.
But then the Dachshund Germans used for weren't toys either. Standard dachshunds go 16-32 lb.
http://www.akc.org/breeds/recbreeds/dach.cfmFrom everything I have read about European badgers they are not quite as nasty as the American badger. European badgers will get as big as 30 lbs but that would be a monster badger there as well as in the U.S.
I have hunted badgers in Oregon, California, New Mexico, Colorado, Texas, Wyoming and Montana over the past 40 years. I have seen quite a few badgers and killed some also. In all those years I have only seen one that went over 30 lbs, 34 lbs to be exact and I had him life sized mounted.

When I was a kid back in the olden days when TV was B&W, I hunted with a hound man who had a standard dachshund that he took along coon hunting. In Southern Oregon there are blackberry bushes all over. It never failed that's where a coon would run to get away from the dogs. The hounds didn't like going into the blackberries and getting all stuck up. That little dachshund would go in and it usually meant one dead coon.
Don't ever doubt the tenacity of the dachshund.
One thing I have noticed about badgers and dogs. Big dogs, other than airedales don't do as well with badgers. Badgers seem to latch onto the long legs and break them. The smaller dog are closer to the ground and quicker and seem better able to control; the badger. Airedales, its chomp and it's done.
My little rat trerriers would intercept badgers every once in a while when l were hunting and they seem to be able to keep the badger busy. I didn't really like them go after a badgers but some tme you just happen on them. I always ended that very quickly.