score:18
Yes, there is.
The deliberations took a while and the participants were all literate, letter-writing folk, so there is actually a lot more documentation about the deliberations than many people think.
I have a book in my library, Slavery and the Founders, that goes over this in its first chapter. It relies primarily on records of the deliberations for its arguments. Prominent are Max Farrand's Records of the Federal Convention of 1787, along with numerous personal correspondence about the deliberations. All the information below is derived from that book, with footnotes pointing back to Farrand.
What he found was that the actual voting for and against the Senate wasn't a small-state vs. large-state split, but rather a Slave state vs Free state split. His thesis is that the design of the Senate, including what powers it was given, was specifically to prevent a Federal government from being able to outlaw slavery based on popular votes from the more populous northern states. This is also why states were allowed to count 3/5ths of their slaves toward their state's representation in The House (which also impacted the Electoral College). A straight-up popular vote would have given slaveholders much less voice in the selection of the POTUS. When next it came to debate that office itself:
On July 17, the Convention considered, and rejected by wide margins, election by the Congress, direct election by the people, and election by the state legislatures. Significantly, the most vocal opposition to election by the people came from three southerners: Charles Pinckney, George Mason, and High Williamson. While Pinckney and Mason argued against the competence of the "people," Williamson was more open about the reasons for southern opposition. He noted that Virginia -- and by extension the rest of the South -- would not be able to elect her leaders president because "her slaves will have no suffrage"
James Madison claimed in his correspondence to be particularly supportive of direct popular election, but saw that Southern states would be faced with a choice of having much less voice that way, or giving their slaves actual votes, neither of which they would ever agree to. So he eventually (on July 20th) came out in support of the Electoral College as a way to give the states weighted voices in the Presidential decision, on the basis that had already been negotiated for Congress (specifically the 3/5ths compromise).