Aiming at the battery pack of chassis power exchange for electric vehicles, a locking device for rapid power change is designed to realize the rapid locking and unlocking of the battery. In order to verify the structural safety of the device, the static and modal characteristics of the device under two typical limit conditions were analyzed by finite element ANSYS software. The results show that the maximum stress of the device under the two working conditions is located at the lock body, and its maximum stress values are 207.63 MPa and 264.18 MPa, respectively, which meet the strength design requirements of the selected materials, and the natural frequencies of the first six modes of the device are greater than the excitation frequencies of the electric vehicle, so the car will not resonate with the device during driving.