Numerical analysis of temperature distribution during ultrasonic welding process for dissimilar automotive alloys

Ultrasonic welding is attracting increasing attentions in lithium battery joining in the field of battery electric vehicle manufacturing. A three-dimensional finite element model was constructed to study the temperature distribution and heat generation in ultrasonic welding process. Numerical analysis showed that heat generation from plastic deformation accounts for nearly a quarter of the whole heat generation (material plastic deformation and interface friction). The fraction changes little with different sequence of specimens. The highest temperature locates at the contact interface of specimens and it is much lower than the melting point of the joining materials. Temperature distribution of the structure is not symmetric, and there are abnormal points under the effect of serrated ridges of sonotrode tip. Welding process can be divided in to three periods based on temperature evolution on the contact interface of lower specimen. The proposed model is validated by comparing simulated temperature evolution with experimental result.