Ingénieur Staff/Senior en Développement de Produits Cellulaires (H/F)

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 a Staff/Senior Product Development Engineer to join our team in our Cheonan, South Korea, location. This person will be responsible for leading the design and development of EV pouch and prismatic cells from concept through mass production, driving key technical decisions, and ensuring product competitiveness in performance, safety, and manufacturability. The ideal candidate will bring 8+ years of cell product development experience and a proven track record of taking products to mass production.

In this role, you will

• Lead product design and technology roadmap development.
• Develop and optimize cell design, including DOEs, production, validation, certification, use cases, DVP, and report templates.
• Coordinate with customers on testing standards, plans, and schedules.
• Serve as technical lead for projects - translate customer requirements into solutions, lead design reviews and risk assessments, and mentor engineers.
• Transfer R&D designs into scalable manufacturing, define process windows and control plans, and resolve critical manufacturing issues.
• Lead mass production readiness assessments and execute Design Verification (DV) evaluations in accordance with product development milestones.
• Evaluate key materials and drive adoption of advanced technologies.
• Follow up on cell testing - conduct tests, analyze results, resolve testing issues, and support the cell development team in failure analysis.
• Track and interpret international standards and regulations, and benchmark against industry-leading testing standards.

We are looking for people who

• Master's degree in a relevant field and at least 8 years of cell development experience, with a proven record of more than one mass-produced product.
• Familiarity with cell design and production, testing standards, and safety regulations.
• Experience with pouch and prismatic cells (electrode design and mechanical optimization); deep understanding of full process flow and ability to define key process windows.
• Proficient in electrochemical and safety testing.
• Strong understanding of Li-ion cell working principles, degradation mechanisms, and influencing factors.
• Strong failure analysis, problem-solving, and data analysis capabilities, with meticulous attention to data and a strong safety mindset.
• Able to quickly understand customer requirements and convert them into design and validation plans.
• Strong teamwork and cross-departmental communication skills.
• Fluent in English (written and spoken) - required for daily communication.
• Strong sense of responsibility and dedication; thorough in work with the ability to thrive in a fast-paced technology or manufacturing environment.
• Preferred: prior work experience at a battery company.
• Preferred: experience developing customer projects and successfully achieving mass production.