Laser welding overlapped Al/Cu metal sheets has developed into a key technology in the manufacturing industry of power battery modules for electric vehicles both domestically and internationally. This article reviews the current application status of multi-scaled material characterization techniques in Al/Cu laser welding from the perspectives of conventional methods (optical microscopy, hardness test and tensile test) and advanced techniques (electron microscopy, X-ray diffraction analysis and x-ray microtomography). The unified international, national or industry standards and specifications are required to be rigorously considered for implementation in this industry. In addition, more advanced characterization techniques should be complementally introduced to enlighten future development direction of Al/Cu laser welding processes for greater achievements. Application and development of real-time online artificial intelligence testing systems are prospected.