Study on the electrical performances of soldered joints between HTS coated-conductors

High performance and reliable joints between 2G HTS coated conductors play a necessary and extremely important role in fabricating superconducting devices. Therefore, developing stable joints and achieving low joint resistance have become an important issue. Long overlap length and low resistivity solder were effective ways to achieve low resistance. In this paper, we fabricate several soldered joints at different temperature and in different lengths, and test their electrical performances at 77 K, self-field. According to experimental and simulation results, we found that quality of soldered joint is influenced not only by solder resistivity, but also by interfacial resistance. In addition, the internal resistance test shows an unusual distribution. The analysis of the overlap area shows that current sharing inside the joint is highly non-uniform along the length and width direction between two connected HTS tapes due to the influence of interfacial resistance and self-field, which is special as “U”-shaped.