A battery includes a positive plate, a negative plate and an insulative separator disposed between the positive plate and the negative plate. Each of the positive plate and the negative plate has a collector and an electrode layer disposed on a surface of the collector. The electrode layer contains an active material. At least one of the positive plate and the negative plate has cracks in a whole area of the electrode layer thereof or at a part of the electrode layer thereof, the part being away from a connector of the one to be coupled to an electrode at least by a predetermined distance. For example, the cracks are formed by drying the electrode layer at a predetermined drying rate.