Bats in dreams often reflect fear tied to the unknown -- and, at the same time, an instinct for navigating situations you can't fully see or understand yet. A bat's reliance on senses other than sight can point to trusting intuition when logic runs out. If the bat frightens you, the dream may be asking what exactly you're afraid to look at directly.
The lord of the second house hath the same strength in hurting, as the lord of the eighth; the lord of the sixth, the same with the lord of the twelfth. - William Lilly (1602.-1681.)