In EV battery packs, the screws that clamp the top cover define both sealing integrity and electrical reliability. Yet these joints often suffer torque decay: the residual torque after tightening is lower than the value originally applied. Elastic recovery of materials, friction relaxation, and structural stress redistribution are the main causes. If torque drops too far, the cover loosens, risking leaks, connection failures, and safety hazards.

Proven countermeasures

1. Multi-step tightening strategy
   • Step 1: Initial torque to seat the screw.
   • Dwell pause: allow gasket and metal to settle.
   • Step 2: Final low-speed rundown to target torque.
   The pause releases instantaneous stress, so the retained torque meets specification.

2. Multi-axis synchronous tightening
   All cover screws are tightened in parallel with identical torque/angle curves. Synchronized waiting and stress-relief phases eliminate the uneven clamping that occurs with sequential tightening.

Danikor support

• High-precision smart drivers execute any multi-step profile (torque, angle, time).
• Multi-axis controller keeps up to 32 spindles perfectly synchronized.
• Real-time data logging proves every joint meets the residual-torque spec.

Using these strategies with Danikor equipment reliably defeats torque decay, ensuring every battery top cover remains secure for the life of the vehicle.