iCloud Drive is not designed to do what you're looking for. iCloud is a syncing solution and not a backup solution. It's designed to provide you with access to all your files from all your devices, keeping them all in sync. It doesn't allow selective file downloads (specifically for what you need).
The only option you have (apart from storing the largest files on a different cloud-enabled provider, like Dropbox), is turn on
Optimize Mac Storage from
System Preferences -> iCloud -> iCloud Drive -> Options. You didn't mention the OS you have so I'm assuming it's Sierra.
See this Apple Support page for other ways of turning on optimized storage using iCloud Drive. From that page:
Optimized Storage in macOS Sierra can save space by storing your content in the cloud and making it available on demand. When storage space is needed, files, photos, movies, email attachments, and other files that you seldom use are stored in the cloud automatically. Each file stays right where you last saved it, and downloads when you open it. Files that you’ve used recently remain on your Mac, along with optimized versions of your photos.