Foil-type strain gauges integrated into PBF-LB/M components: signal validation and case study on battery cell caps

This study investigated and validated the integration of non-weldable foil-type strain gauges (SGs) into components fabricated via powder bed fusion of metals using a laser beam (PBF-LB/M), with a particular focus on signal quality, robustness, and reproducibility. Key factors influencing the interaction between the SG integration, the PBF-LB/M process, and the SG measurement behavior were examined. These included the effects of differences in build plate heating temperatures, SG positioning misalignment, and variations in the adhesive amount. Measurements of the SG signal consistently demonstrated precise and reliable signal quality across multiple integration attempts, emphasizing the industrial potential of this approach. The capability of the integrated SGs was further evaluated in a case study involving lithium-ion batteries (LIBs), where a SG was embedded within a cell cap. To improve temperature compensation of the strain measurement, a second cell cap was fabricated, integrating both a SG and a resistance thermometer to enable simultaneous measurement of strain and temperature. This configuration allowed for the acquisition of strain signals with minimal influence from temperature-induced strain variations. Overall, this study confirmed the feasibility of integrating non-weldable SGs into PBF-LB/M components, providing valuable insights into strain measurement signals and their reliability for industrial applications.