Investigation of ReBCO Conductor Tape Joints for Superconducting Applications

Electric joints are an essential part of every current carrying device. In the field of high temperature superconducting applications, quality of a contact between superconducting tapes and electric terminations is crucial for the device performance. When connecting tapes to each other, soldered contacts are commonly used. Recent reports have demonstrated that the resistance of this contact depends on the pressure applied during a soldering process, and the soldering temperature. When superconducting tapes are used in cables or in other applications, they have to be connected to copper terminations, e.g., to a current lead. Thus, tape-to-copper contacts are important. In superconducting cables, tapes are stacked together having a resistive electrical contact from tape to tape. The resistance of this contact depends on the pressure applied on the stack due to, for example, jacketing of the cable or during cool down. In this paper, the dependence of resistance between tapes on the applied pressure is reported. In this contribution two kinds of contacts, soldered ones and mechanical pressed, are presented and discussed. They are realized, respectively, between two superconducting ReBCO tapes from SuperPower, Inc. (SPI) and SuNAM, which were used for manufacturing HTS cable, and between superconducting tapes and copper.