Assembly Process Engineer - 3C Battery

Factorial Energy is seeking an Assembly Process Engineer to join our team in our Cheonan, South Korea location. This person will be responsible for the development, optimization, and scale-up of pouch cell assembly processes for our Silicon Power Cell line, covering the full assembly chain from post-stacking through final sealing. The ideal candidate brings deep hands-on expertise in pouch stacking cell assembly, is comfortable driving yield improvement and process standardization, and thrives in an early-stage, fast-moving manufacturing environment. • Lead development and optimization of pouch stacking cell assembly processes covering electrode alignment, stacking compaction, tab forming, pre-sealing, and final sealing • Define and maintain process windows for all key assembly parameters, establishing CTQs and process standards • Establish and maintain SOPs, PFMEA, and Control Plans for all assembly process steps • Adapt assembly structures and processes to accommodate silicon anode volume expansion characteristics, minimizing stacking flatness deviation and sealing reliability risks • Collaborate with R&D and electrode teams to evaluate silicon anode impact on stacking flatness, electrode slippage, and sealing integrity • Develop and validate process parameters to mitigate assembly and reliability risks caused by Si anode volume changes during cycling • Lead assembly process transfer from lab/pilot scale through EVT/DVT/PVT/MP stages • Identify yield and cycle time bottlenecks and develop ramp-up plans targeting 2–5% yield improvement • Support FAT/SAT and equipment qualification (IQ/OQ/PQ) for assembly equipment • Partner with equipment vendors on assembly fixture, tooling, and automation solution design and validation • Apply DOE, SPC, 5-Why, and fishbone analysis to identify root causes of assembly defects (tab misalignment, sealing defects, stacking wrinkles) • Drive cross-functional (R&D/Quality/Equipment) issue resolution and CAPA closure • Document assembly process experience to build replicable technical solutions

• Have 3+ years of hands-on experience in lithium-ion pouch cell assembly process development or manufacturing • Have at least 2 years of experience in pouch stacking cell assembly processes • Have led or substantially contributed to at least one full NPI or mass production ramp-up project • Have deep understanding of pouch stacking cell structures and key assembly control points • Have experience with silicon anode pouch cell assembly or high-expansion electrode systems preferred • Are familiar with process qualification frameworks (DFMEA → PFMEA → CP → SOP) • Have basic mechanical assembly knowledge; ability to interpret mechanical drawings and understand assembly tolerances • Are proficient in DOE, SPC, and data analysis tools • Have experience with defect analysis methodologies (5-Why, fishbone, 8D) • Hold a Bachelor's degree or higher in Mechanical Engineering, Materials Science, Chemical Engineering, or related field • Have experience in pilot line or new production line setup from 0 to 1 (preferred) • Are familiar with IATF 16949 and APQP systems (preferred)