Every post has a hidden timeline to it, which has detailed info regarding the votes a post has aggregated each day, with links in the form of http://[sitename].stackexchange.com/posts/[postID]/timeline. (But obviously not the info about who voted)
For instance, the timeline link for this question is http://meta.stackexchange.com/posts/290708/timelinehttps://meta.stackexchange.com/posts/290708/timeline.
You need the established userestablished user privilege to see the breakdown of votes though, and without it, you will only see the total score (upvotes−downvotes) for each day.
As animuson points out in a commentpoints out in a comment, it's only a sum of votes a post has gained each day, but it's the analysis with the most details about votes that you can get.