Meaning
Practice of inserting thin spacers of varying thicknesses into an assembly compensates for dimensional stack-up tolerances in mechanical structures. Manufacturing technicians employ selective shimming when building battery modules to ensure uniform contact pressure across all cells in the pack. This method corrects for minor variations in cell thickness arising from the manufacturing process.
Assembly Optimization
Precision measurement stations calculate the accumulated thickness of a cell stack before the endplates are permanently secured. Based on this measurement, the assembly system selects the optimal shim thickness to achieve the targeted compression. Using selective shimming reduces the reliance on extremely tight tolerances during individual cell manufacturing.
Pressure Distribution
Even distribution of compressive forces prevents localized stress concentrations that could damage the delicate internal layers of the cells. Implementing selective shimming prevents the formation of dead zones where low compression would allow the electrodes to separate. Consistent pressure across the cell faces ensures uniform electrochemical activity and heat generation.
Production Efficiency
Automated shim dispensers integrate directly into the robotic assembly line to maintain high throughput. The implementation of selective shimming minimizes the scrap rate of expensive housing components by compensating for dimensional deviations on the fly. Digital records of the shim thickness selected for each module are stored for quality traceability.
