Automated Assembly of Battery Modules in a Battery Pack

The customer required a fully automated assembly process for VDA355 and MEB battery modules installed in a battery pack frame.
From the early analysis phase, it was clear that standard automation solutions would not be sufficient due to wide range mechanical tolerances and strict quality requirements.

The key challenges included:

• Low manufacturing accuracy of the battery pack frame (tolerances up to ±1 mm)
• Mounting pins with deviations from verticality of up to 9 mm over a length of 350 mm
• Requirement to maintain correct polarity orientation of each module
• Assembly of up to three module levels within one battery pack
• Cycle time below 30 seconds per module

The customer’s objective was to achieve a damage-free, precise, and fully automated assembly process, without operator involvement.

We developed a customized automation concept tailored specifically to the project’s mechanical and process constraints.

The solution was based on:

• Two FANUC industrial robots, each assigned a dedicated role in the assembly process
• A proprietary pin positioning system implemented on the first robot, compensating for pin misalignment and frame tolerances
• A module gripper with an integrated Cognex vision system on the second robot, ensuring precise positioning and correct polarity orientation
• Tight integration of robotics and vision to enable adaptive, tolerance-compensating assembly

This approach provided full control over positioning accuracy while maintaining the required cycle time.

Process validation confirmed that the system:

• Reliably compensates for frame and pin tolerances
• Maintains correct module polarity orientation throughout the assembly process
• Enables precise, repeatable module placement across multiple assembly levels
• Meets the required cycle time of < 30 seconds per module
• Operates in a fully automated mode, without manual intervention

The implemented solution enabled:

• Safe, precise installation of battery modules
• Stable assembly of up to three module levels in one battery pack
• Repeatable process performance, independent of component tolerances

• Elimination of module damage risk during assembly
• Zero polarity orientation errors, ensured by vision guidance
• Significant increase in productivity
• Complete removal of manual operations, improving safety and repeatability
• Scalable automation concept, ready for future production expansion

This case study demonstrates how a custom automation approach, combining robotics, vision systems, and proprietary positioning solutions, enables reliable battery module assembly even under challenging tolerance conditions.

By addressing variability at the process level, we delivered a future-ready, fully automated solution aligned with the customer’s production goals.