Is there a difference between the two words for yes?
According to my very limited research, "はい" is used as a more formal way of saying yes where "ええ" is used in less formal situations.
Pretty much. It's like comparing "yes" to "yeah" or "uh-huh."
https://forum.duolingo.com/comment/27499061 => Different points between ええ , はい, and うん