The union-closed sets conjecture, also known as Frankl's conjecture, is a well-studied problem with various formulations. In terms of lattices, the conjecture states that every finite lattice $L$ with more than one element contains a join-irreducible element that is less than or equal to at most half of the elements in $L$. In this work, we obtain several necessary conditions for any counterexample $\tilde{L}$ of minimum size.