Battery Cell Engineer (R&D) — Prototyping & Testing

PolyJoule, Inc.; Billerica (MA); On-site; USD 120,000 - 160,000; Full time

Benefits offered by this job

Competitive compensation

Job summary

PolyJoule, Inc. is seeking a Battery Cell Engineer to lead development and testing of prototype battery cells at our R&D site in Billerica, MA.

You will assemble pouch and prismatic cells, optimize electrode formulations, and perform electrochemical testing to accelerate material and product development. The role requires hands‑on lab work, data analysis, and close collaboration with chemists and engineers to ensure safe, manufacturable designs.

Qualifications

• B.S. or M.S. in Chemical Engineering, Materials Science, Electrochemistry, or related field.
• Hands‑on experience with battery cell assembly and electrochemical testing.
• Familiarity with non‑aqueous and aqueous electrochemistry and battery characterization techniques.
• Strong analytical skills and proficiency with data analysis tools (Excel required).
• Ability to work independently and collaboratively in a fast‑paced R&D environment.
• Excellent organizational, documentation, and communication skills.
• Passion for innovation and sustainability in energy storage technologies.

Responsibilities

• Assemble prototype battery cells (pouch and prismatic) using automated and manual techniques for electrode fabrication, cell stacking, tab welding, enclosure sealing, and electrolyte filling.
• Design and optimize electrode formulations, including slurry preparation and coating processes such as slot‑die, doctor blade, and dip coating; oversee subsequent steps including calendaring, precision cutting for electrode geometry, and controlled drying to ensure uniformity and performance.
• Contribute to defining lab‑scale assembly workflows for novel chemistries to enable rapid prototyping and process optimization.
• Conduct electrochemical performance testing, including charge/discharge cycling, rate capability, cyclic voltammetry, and impedance spectroscopy.
• Perform stress testing and accelerated aging protocols to evaluate durability under various conditions; analyze failure modes through post‑mortem techniques to identify root causes and inform design improvements.
• Collaborate with chemists and engineers to integrate new materials into functional cells; evaluate compatibility of electrodes, electrolytes, separators, and other components to ensure optimal performance, safety, and manufacturability in prototype and lab‑scale assemblies.
• Maintain accurate documentation of fabrication parameters and test results, including detailed bills of materials (BOMs), comprehensive experiment records, and version‑controlled files to ensure traceability, reproducibility, and alignment with quality standards.
• Support scale‑up efforts and assist in transitioning successful designs to pilot production.
• Communicate technical results and milestones to leadership and cross‑functional teams for decision‑making.
• Participate in vendor and material sourcing, qualification, and technical due diligence for battery components.

Skills

Battery cell assembly

Electrochemical testing

Data analysis

Independent & collaborative work

Documentation & communication

Education

B.S./M.S. in Chemical Engineering / Materials Science / Electrochemistry

Tools

Excel

Python

MATLAB

Git / version control

CSV/Excel data tools

Job description

PolyJoule, Inc. is seeking a Battery Cell Engineer to lead development and testing of prototype battery cells at our R&D site in Billerica, MA.

You will assemble pouch and prismatic cells, optimize electrode formulations, and perform electrochemical testing to accelerate material and product development. The role requires hands‑on lab work, data analysis, and close collaboration with chemists and engineers to ensure safe, manufacturable designs.