Can you elaborate on this? My guess would be, that because of their status as a government backed research institute, they invent a lot, but let others do the commercialisation. So patent fees seem like a natural choice for them, to recover their investments.

Fraunhofer has a ton of top of the line innovations. I'm glad it exists. If the only way to exist is for them to collect on patents they've produced, I don't see the issue.