RCIPL
Repositório Institucional do Politécnico de Lisboa
Entradas recentes
Thermo-electrical performance of hybrid busbars: an experimental and numerical investigation
Publication . Sampaio, Rui F. V.; Pragana, João P. M.; Bragança, Ivo M. F.; Silva, Carlos M. A.; Martins, Paulo A. F.
This paper is focused on hybrid busbars made from aluminum and copper with the purpose of analyzing the influence of temperature on the electric performance of the joints. The methodology involves the fabrication of fastened, friction stir spot welded, sheet-bulk compressed, and injection lap riveted unit cells that are representative of the different types of hybrid busbars joints, the development of a special purpose laboratory apparatus for thermo-electrical measurements, and numerical simulation with a finite element computer program developed by the authors. Results are a step forward in understanding the variation of the electrical resistance of hybrid busbars with temperature and allow concluding that an increase above 30% is expected when the temperature in service reaches the limiting value defined by the IEEE standard for metal-clad switchgear.
Electricity as a Commodity: Liberalisation Outcomes, Market Concentration and Switching Dynamics
Publication . Domingues, Nuno Soares
Development of a decision support system in oncology for prostate adenocarcinoma
Publication . Costa, João Pedro; Moura, Filipe; Domingues, Nuno
On the utilization of radial extrusion to characterize fracture forming limits. Part II: testing and modelling
Publication . Sampaio, Rui F. V.; Pragana; João P. M.; Bragança, Ivo M. F.; Silva, Carlos M. A.; Nielsen, Chris V.; Martins, Paulo A.F.
Thermal-electrical analysis of a novel interconnection for hybrid busbars in electric vehicle batteries
Publication . Costa, D. P. M. da; Kasaei, M. M.; Carbas, R. J. C.; Marques, E. A. S.; Sampaio, R. F. V.; Bragança, I. M. F.; Silva, L. F. M. da; Bragança, Ivo; Elsevier
Reliable and efficient busbar connections are critical for electric vehicle battery performance, yet conventional
joining methods struggle with joining dissimilar materials such as copper and aluminum. This paper investigates
a novel solution for joining hybrid copper-aluminum busbars using a technique called hole hemming, which
eliminates the need for heating or additional elements. The focus is placed on the thermal-electrical performance
of hole-hemming joints. Two configurations are studied: joints with and without branches. Numerical models
analyse how sheet thickness affects temperature, electric current density, electric potential, and resistance,
including models with cantered holes to study hole inclusion effects. Experimental tests are conducted on ma
terial strips and unit cells to assess electrical resistance changes with temperature and the effect of Joule heating
on joint configurations. Compression using a hydraulic press is applied to improve contact, leading to significant
electrical resistance improvements (78 % reduction for branched joints and 36 % for branchless ones). Me
chanical shear tests before and after compression show a peak shear load of 4.54 kN and 13.84 mm displacement
for branched joints, with slightly lower values for branchless joints. Despite a minor decrease in mechanical
performance after compression, the improved thermal-electrical performance of the joints outweighs this. The
findings highlight the promising potential of hole-hemmed joints for enhancing hybrid busbar connections.