Effect of Surface Stripes on Electrical-Thermal–Mechanical Behaviors and Interfacial Bonding Formation in Parallel Gap Resistance Welding of Ag Interconnectors

This work focuses on investigating the effects of surface stripes of materials on parallel gap resistance welding (PGRW) of Ag interconnectors. Two configurations were compared: (1) surface strips on two interconnectors to be joined are crossed, (2) surface strips on the two interconnectors are parallel. Effects of surface stripes on the electrical-thermal–mechanical behaviors in PGRW of Al interconnectors were investigated by a combination of micro-scale and macro-scale modeling. Effects of the surface stripes on the mechanical properties of welds were evaluated. The interfacial bonding formations in welding were further revealed by micro-scale modeling. The simulation results indicate the contact electrical conductance of the interface with crossed surface stripes is almost half of that with parallel surface stripes and needs higher pressure to become stable. The interface with crossed surface stripes has much lower contact thermal conductance than that with parallel surface stripes. In comparison to the parallel surface stripes, the crossed surface stripes promote the Joule heat generation in the weld, in particular the upper Ag interconnector, by increasing the contact resistance between the Ag–Ag interconnectors. Meanwhile, the increased contact thermal resistance inhibits the thermal dissipation from the upper Ag to the lower one. These factors result in the relatively high temperature in the weld with crossed surface stripes. The welds with parallel surface stripes always have higher tensile-peel properties than those with crossed stripes due to the greater bonded area and less thermal damage on the HAZ. Welding with parallel surface stripes tends to create a greater contact area than that with crossed surface stripes at the same temperature.