how much will the hybrid battery cost?

Hello, the dealership is the only real source for a hybrid battery for this vehicle. As such, they would have the latest pricing. Pricing also depends on if you have a "Energi" model or a Hybrid model -- they are different batteries. Some batteries are available in the aftermarket, however, your experience with them may vary. I would stay in touch with your local Ford dealership in the event you have a battery failure; even after the warranty period, especially if you are loyal client, they may offer you financial assistance if one fails.