Reinforcement frame for a battery pack of an electric or hybrid vehicle, reinforced battery pack and process for assembling said battery pack

A reinforcement frame () for a battery pack () of an electric or hybrid vehicle (), the battery pack including a plurality of battery cells lying on and secured to a shield element, the reinforcement frame including at least: a reinforcement frame fastening portion () provided to be secured to both the battery pack and the body of the vehicle, and a reinforcement frame hollow portion () provided to surround at least the battery cells.