To achieve the approriate trade-off between the low charing delay and enough self-protection ability in the NI REBCO coil, the controllable Cu layer structure in REBCO tape is essential, which can cause required electrical and thermal properties in both the radial and circumferential direction. In this paper, the correlation between the material characteristics of the copper layer on the electrical and thermal properties of REBCO was explored by investigating the REBCO tape with different Cu layer thicknesses. The influence of charging decay, self-protection, and cold shrinkage stress on the REBCO coil performance was also evaluated based on three tapes. Three new findings showed the possible dominant factor on electrical and thermal properties in either radial or circumferential direction. Unlike the traditional electroplated layer, the Cu layer in the SP3 sample has piecemeal Cu grains, which may be the primary factor in significantly increasing the electrical resistivity and decreasing the thermal conductivity significantly. In the radial direction, the nonuniform top, bottom, and even side thickness of the Cu layer could increase the electrical resistivity and thermal conductivity. And the bad corner contact quality between the Cu and Ag/REBCO could be an important factor. Furthermore, the Cu layer purity may be significantly lower than previously thought. Using the electrical resistivity and thermal conductivity values of pure Cu as the Cu layer in the simulation could result in significant errors. This study provides possible directions for finding a method to control the properties of the Cu layer of REBCO commercial tape, which can better fit different application scenarios.

为了在 NI REBCO 线圈中实现低炭化延迟和足够的自我保护能力之间的适当权衡，REBCO 胶带中可控的 Cu 层结构是必不可少的，这可以在径向和圆周方向上产生所需的电和热性能. 本文通过研究不同铜层厚度的REBCO胶带，探讨了铜层材料特性对REBCO电学和热学性能的相关性。还基于三个胶带评估了充电衰减、自我保护和冷缩应力对 REBCO 线圈性能的影响。三项新发现显示了径向或圆周方向上电气和热性能的可能主导因素。不同于传统的电镀层，SP3 样品中的 Cu 层具有零碎的 Cu 晶粒，这可能是显着增加电阻率和显着降低热导率的主要因素。在径向上，Cu 层的顶部、底部和均匀的侧面厚度不均匀会增加电阻率和热导率。Cu 和 Ag/REBCO 之间不良的角接触质量可能是一个重要因素。此外，Cu 层的纯度可能比以前认为的要低得多。在模拟中使用纯铜的电阻率和热导率值作为铜层可能会导致重大错误。本研究为寻找控制 REBCO 商用胶带铜层特性的方法提供了可能的方向，