Speaker
Description
High-temperature superconducting (HTS) rare-earth barium copper oxide (REBCO) magnets are typically fabricated in a stacked configuration of pancake coils. Conventionally, the electrical connections between pancake coils is achieved by joining the REBCO splice with soldering process. In this process, solder flux is applied to remove oxide layer on the REBCO tape surface and to enhance solder adhesion. However, the solder flux penetrates into the inside of the coil around the joint section, leading to oxidation and corrosion of the conductors and degrading the magnet performance.
In this study, we adopted a method of connecting pancake coils solely through contact without using a soldering process, so called solderless joint, and proposed a mechanical structure applying radial pressure for this purpose. A solenoid magnet system was designed and constructed based on this proposed concept, followed by 77 K liquid-nitrogen and 20 K conduction cooling tests. Experimental results confirmed that the solderless joint could achieve resistances in the tens to hundreds of nano-Ohms range and preserve magnet performance during repetitive tests. These results demonstrated the feasibility and reliability of solderless mechanical joints as an alternative to conventional soldered joints while offering advantages in terms of ease of assembly and maintenance.
Acknowledgement
This research was supported in part by National R&D Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT (2022M3I9A1072846), and in part by the Applied Superconductivity Center, Electric Power Research Institute of Seoul National University.
