Quell literally means "well" or "wellspring". It's a poetic spelling of Quelle It's cognate with Swedish källa and with Swedish names like Kville.
They always pronounce the u as a Swedish u - semi-illiterates never know that the Swedish pronounciation is the most uncommon pronunciation of that letter and, for some reason, with the stress on the last syllable.
If I buy something with a foreign name, I check what it means and how to correctly pronounce it, of course.