In the field of new-energy vehicles, the screw-tightening quality of the PACK battery cover is critical for the overall performance and safety of the battery module. However, during mass production, torque decay has always been a key factor that undermines tightening reliability.

Torque decay refers to the phenomenon in which, after a screw is tightened, the residual torque actually retained becomes lower than the target torque that was set during tightening. This drop is caused by the elastic deformation of the materials involved, friction effects, and structural stresses. Such decay may loosen the battery cover, impair the sealing of the pack, destabilize electrical connections, and introduce safety hazards.

To solve this problem, a multi-step tightening strategy has proved effective. After an initial tightening step, the controller pauses for a short dwell time. This gives the materials time to accommodate the initial deformation. The screw is then driven again at low speed until the final target torque is reached. This sequence allows the elastic deformation of the screw to adjust itself and releases part of the transient stress that was built up. Consequently, the residual torque meets specification and the risk of torque decay is greatly reduced.

In addition, when many screws are involved, an advanced multi-spindle synchronous-tightening strategy plays an important role. By synchronizing the program nodes for every screw, simultaneous dwell and simultaneous stress relief are achieved. This avoids torque scatter caused by different tightening sequences. Such synchronized tightening equalizes the load on every screw, minimizes mutual stress interference, and raises both the assembly quality and the long-term stability of the whole battery cover.

Danikor intelligent electric screwdrivers provide strong support during this process. They offer high-precision torque control and intelligent program-setting functions, so the multi-step strategy can be executed accurately, with exact torque and angle parameters for every stage. Moreover, Danikor’s multi-spindle synchronous-control technology can tighten many screws at once while keeping the whole process perfectly synchronized and uniform. This capability further suppresses torque decay, improves the assembly quality of the PACK battery cover, and guarantees safe and reliable operation of new-energy vehicle battery modules.

In short, by adopting multi-step tightening and advanced multi-spindle synchronous-tightening strategies, and by employing state-of-the-art equipment such as Danikor intelligent electric screwdrivers, manufacturers can effectively overcome torque-decay difficulties when tightening PACK battery covers. These measures meet the stringent assembly-quality requirements of the new-energy vehicle industry and continue to advance the manufacturing technology of new-energy vehicles.