Assembly Process Engineer/ Senior Engineer - 3C Battery

Who We Are

Factorial Energy is a pioneering U.S.-based solid-state battery company driving the future of energy storage and electrification. Partnered with global leaders including Mercedes-Benz, Stellantis, Hyundai, and Kia, Factorial is at the forefront of developing next-generation e-mobility platforms for commercial, defense, and consumer applications—spanning electric vehicles (EVs), drones, eVTOL aircraft, power tools, marine systems, robotics, and more. The company has achieved multiple industry firsts, including being the first to power a demonstration vehicle with a global OEM (Mercedes- Benz) which achieved over 1,200 km (749 mi) of range, and the first to earn UN 38.3 certification for automotive-sized lithium-metal solid-state cells, the first to deliver B-samples of automotive-sized solid-state batteries to major OEMs. 

The Opportunity:

Factorial Energy is seeking an Assembly Process Engineer/ Senior 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. 

In this role, you will:

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 

We are looking for people who:

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) 

Work Location:

Cheonan, South Korea

Factorial Energy is an equal opportunity employer that values diversity at all levels. All qualified applicants, regardless of personal characteristics, are encouraged to apply.

To request a reasonable accommodation to complete an application, job interview, and/or to otherwise participate in the hiring process, please contact ([email protected])