The invention discloses a storage battery heavy rail car. The storage battery heavy rail car is characterized by comprising a frame, a shaft box, wheelsets and braking devices, wherein a wheel is arranged at each of two ends of each wheelset; a braking device is arranged on each wheel; each braking device comprises a first connection plate, a second connection plate and an air cylinder; each air cylinder comprises a braking cylinder body, a first connection shaft, a second connection shaft, a piston and a spring; when a pneumatic system on the frame has a fault and is powered off, the springsdrive the first connection shafts and the second connection shafts to move to get close to one end of an inflation cavity under the action of an elastic restoring force, and the first connection plates and the second connection plates are driven to rotate in opposite directions, so that the included angle between the first connection plates and the second connection plates is reduced, and furthermore, the wheels between the first connection plates and the second connection plates are clamped to realize braking; and a safety accident caused by a power failure is avoided.