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 is seeking an experienced Formation Process Engineer/ Senior Engineer to lead the development, optimization, and mass-production support of lithium-ion battery formation (Formation) and grading (Capacity Sorting) processes for consumer electronics applications. This role covers the full process lifecycle — from R&D validation through pilot scale-up to high-volume manufacturing — with a focus on maximizing initial Coulombic efficiency (ICE), capacity consistency, and cycle life. The ideal candidate will bring a strong electrochemical engineering background, cross-functional collaboration skills, and a data-driven approach to process improvement and equipment innovation. 

In this role, you will:

• Lead the development and parameter optimization of formation protocols for consumer lithium-ion cells (cylindrical, pouch, and prismatic), including pre-formation, standard formation, and step-charge strategies. 
• Design and validate optimal formation recipes (charge/discharge C-rates, temperature windows, cutoff conditions) to maximize initial Coulombic efficiency (ICE) and SEI film uniformity. 
• Establish capacity grading (sorting) specifications, defining key binning parameters including capacity, DC internal resistance (DCIR), and self-discharge rate. 
• Develop product-specific formation programs tailored to varying cell chemistries and consumer device requirements (high energy density, high rate, or long cycle life). 
• Identify root causes of formation and grading anomalies — including low capacity, high impedance, abnormal voltage plateaus, and lithium plating — and implement effective corrective and preventive actions (CAPA). 
• Apply SPC, DOE, and FMEA methodologies to reduce batch-to-batch variation and continuously improve process capability (Cpk). 
• Partner with QA/QE to define inspection standards (IQC/IPQC/OQC) for the formation segment, ensuring outgoing quality meets customer requirements. 
• Analyze field return failure modes and author 8D reports to support technical customer response.
• Optimize formation line takt time and equipment overall equipment effectiveness (OEE), reducing energy consumption per cell and WIP inventory. 
• Drive process transfers across all development stages: lab bench → pilot line → mass production, including process reviews, first article inspections, and Measurement System Analysis (MSA). 
• Develop and maintain preventive maintenance (PM) plans for formation equipment to minimize unplanned downtime and ensure line continuity. 
• Advance automation of cell loading/unloading, in-line voltage/temperature monitoring, and MES data integration to improve smart manufacturing capabilities.
• Collaborate with formation cycler suppliers to define next-generation equipment specifications, covering high-precision current control, independent multi-channel testing, and temperature regulation accuracy. 
• Lead FAT/SAT acceptance testing for formation equipment and establish OQ/PQ qualification protocols. 
• Evaluate and introduce advanced in-situ measurement technologies (e.g., online EIS, gas evolution detection) to enhance process visibility and control. 

We are looking for people who:

• 3+ years of hands-on experience in lithium-ion battery formation and capacity grading processes; background in consumer battery (TWS, mobile, wearable) mass production lines strongly preferred. 
• Deep understanding of formation fundamentals: SEI layer formation, gas evolution behavior, lithium deposition suppression, and electrolyte decomposition reactions. 
• Proficiency in DOE, SPC, FMEA, and Six Sigma methodologies; Green Belt or Black Belt certification is a plus. 
• Demonstrated experience in process transfer from R&D to high-volume manufacturing; familiarity with PPAP/APQP workflows. 
• Familiarity with major formation cycler platforms (e.g., Neware, Landt, Arbin, Basytec) and their programming logic; ability to independently troubleshoot equipment faults. 
• Proficiency in electrochemical testing techniques: EIS, DCIR, self-discharge, and battery analysis software (BTS, Arbin, etc.). 
• Skilled in JMP, Minitab, Python, or Excel for large-scale data analysis and visualization; ability to extract actionable process insights from manufacturing data. 
• Bachelor's degree or above in Chemical Engineering, Materials Science, Electrochemistry, or a related field (Master's preferred). 
• Strong cross-functional communication skills; ability to author technical reports and engage in technical discussions with domestic and international customers. 

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 (recruitment@factorialenergy.com)