Joint Formation in Multi-Layered Ultrasonic Welding of Ni-Coated Cu and the Effect of Preheating
Joint Formation in Multi-Layered Ultrasonic Welding of Ni-Coated Cu and the Effect of Preheating
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DOI：
10.1115/msec2018-6328
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发表时间：
2018-06
期刊：
影响因子：
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通讯作者：
Ying Luo;S. Hu;E. Kannatey-Asibu;Haseung Chung;W. Cai;Teresa Rinker;Jeffrey Abell
中科院分区：
文献类型：
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作者：
Ying Luo;S. Hu;E. Kannatey-Asibu;Haseung Chung;W. Cai;Teresa Rinker;Jeffrey Abell
多层超声波焊接（USW）广泛用于锂离子电池中电极或极耳的连接。为了获得高质量的接头并增强焊接工艺的鲁棒性，非常需要改进对接头形成的理解。本文研究了4层镍包铜超声波焊接在室温和预热条件下的单界面接头形成和接头从界面到界面的扩展。结果表明，接头的形成主要有三种机制：Ni-Ni键合与最小机械互锁、Ni-Ni键合与中等机械互锁以及Ni-Ni键合、Cu-Cu键合与严重机械互锁的组合。结果还表明，接头从靠近超声极侧的界面扩展到靠近砧侧的界面。进一步观察到，通过工艺预热，尤其是在最靠近砧的界面处，可以加速接头形成并且可以提高接头强度。预热的影响在工艺的早期阶段最为显著，并随着工艺的进行而减小。预热的良好效果提高了多层超声波的鲁棒性。
Multi-layered ultrasonic welding (USW) is widely used in joining of electrodes or tabs in lithium-ion batteries. To achieve quality joints and enhance the welding process robustness, an improved understanding of the joint formation is highly desirable. In this paper, USW of 4-layered Ni-coated Cu is studied to investigate the joint formation at a single interface and joint propagation from interface to interface under both ambient and preheated conditions. The results indicate that joint formation involves three major mechanisms: Ni-Ni bonding with minimal mechanical interlocking, Ni-Ni bonding with moderate mechanical interlocking, and a combination of Ni-Ni bonding, Cu-Cu bonding, and severe mechanical interlocking. Results also show that joints propagate from the interface close to the sonotrode side to that close to the anvil side. It is further observed that the joint formation can be accelerated and the joint strength can be improved with process preheating, especially at the interface closest to the anvil. The effect of preheating is most significant during the early stage of the process, and diminishes as process progresses. The favorable effects of preheating improve the robustness of multi-layered USW.