Welding doi: 10.3390/welding1010003

Authors: Andreas Walter Jilg Michał Jerzy Szulc Jochen Schein

This study presents an optical reconstruction method for the quantitative evaluation of arc position in stud welding. Knowledge of the instantaneous arc position is essential for understanding arc dynamics and enabling process monitoring and control. The relative spatial position of the arc is determined from the geometric centroid of an intensity distribution recorded by eight directionally arranged photodiodes. Calculated using area-weighted polygon decomposition, the centroid provides a consistent two-dimensional representation of arc motion and enables the derivation of angular and amplitude-related quantities. The method is not intended to deliver absolute metric arc positions but to provide a reliable relative description of arc movement. Whereas laser-based stereoscopic systems require an additional illumination arrangement and high-speed camera systems rely on the acquisition and processing of image sequences, the proposed method evaluates photodiode signals acquired directly within the welding hardware. This enables a compact, process-integrated implementation suitable for real-time arc monitoring. The proposed reconstruction method is evaluated under conventional direct-current, magnetically influenced direct-current, and alternating-current welding conditions. Validation against stereoscopic high-speed camera measurements showed good agreement in trajectory shape and dynamic behaviour, with mean Pearson correlation coefficients above 0.97 and a mean Euclidean deviation of 0.59 mm, corresponding to 10.4%, for rotational arc motion. The approach thus enables reliable analysis of arc movement and spatial energy distribution over the entire welding duration. Overall, the proposed methodology provides a robust and efficient tool for quantitative arc motion analysis in stud welding.

Welding doi: 10.3390/welding1010002

Authors: Gonçalo F. S. Ferreira Mohammad Mehdi Kasaei Alireza Akhavan-Safar Ricardo J. C. Carbas Hossein Malekinejad Eduardo A. S. Marques Lucas F. M. da Silva

Busbars are key components in electric vehicle (EV) battery packs, providing electrical connections between individual cells to form modules and between modules to form the full battery pack while operating under demanding environmental conditions. In this context, busbar-to-busbar and busbar-to-cell terminal interconnections are critical to overall system performance, making their design and reliability of paramount importance. Any failure occurring in these interconnections, including thermal fatigue, vibration-induced cracking, corrosion, and interfacial degradation, can compromise joint integrity and result in a progressive increase in electrical resistance. In this review paper, to support the selection and development of suitable joining solutions for busbar interconnections, a detailed analysis of joining technologies is presented, including mechanical fastening, welding, and joining by forming techniques. Their performance is compared in terms of electrical resistance, mechanical strength, fatigue behavior, and suitability for busbar interconnections. This work outlines current limitations in the understanding and characterization of mechanical, electrical, and fatigue behavior and identifies key research gaps, particularly the lack of fatigue data under coupled electro-thermo-mechanical loading that is representative of real EV operation. The review thus provides a comprehensive foundation for the design and optimization of reliable interconnections, supporting improved durability, safety, and sustainability in next-generation EV battery systems.

Welding doi: 10.3390/welding1010001

Authors: Lucas F. M. da Silva

Joining technologies are fundamental to modern society [...]