The electoral college is made of of presidential electors, each representing one electoral vote for each state. Although I don't think they are legally bound to vote for the electoral votes that represent their state, the electors always do.

There has never been a case where a large number of electors voted against the way their state's election apportioned electoral votes. I believe there may be a few cases where one or two electors (out of 538) voted differently than their state's election results, and there was discussion of something like that happening with all the fraudulent stuff in Florida in 2000, but nothing came of it, and as Bill said, nothing ever will.