Python Test Engineer Jobs in Fremont, CA (NOW HIRING)

Coreshell's metallurgical Silicon anode technology delivers high capacity, fast-charging, and superior safety. Our low-cost Silicon-dominant batteries have higher energy density, superior intrinsic thermal safety, and significantly lower cost/kWh compared to current LIBs. Coreshell's Si anode material is lower than the cost of graphite and utilizes the largest abundant critical mineral supply in the US and Europe. We strive to transform the global energy and transportation market by enabling cost effective and secure domestic battery supply. 

Position:

This Battery Test Engineer role owns the battery testing infrastructure that underpins Coreshell’s cell development and manufacturing operations. You will be responsible for the installation, commissioning, calibration, and ongoing maintenance of all electrochemical test equipment and will serve as the primary point of contact for hardware vendors. Because this role sits at the critical junction between manufacturing and electrochemical testing, you will also take on key data responsibilities: ensuring that test data is accurately captured, traceable, and structured for downstream analysis by the data science and cell engineering teams. The ideal candidate has hands-on experience managing battery test labs at scale, a meticulous approach to calibration and data integrity, and the ability to keep a growing test infrastructure running reliably in a fast-paced development environment.

Core Responsibilities:

• Own the installation, commissioning, calibration, maintenance, and continuous improvement of battery test infrastructure, including cyclers, environmental chambers, incubators, and other analytical and electrochemical characterization equipment, ensuring high uptime and reliable operation.
• Serve as the primary point of contact for test equipment vendors: managing procurement, service contracts, updates, and technical support.
• Develop and maintain calibration and preventive maintenance programs for all testing equipment.
• Design, build, and validate experimental test setups such as instrumented cell fixtures or specialized electrochemical test apparatus.
• Develop and maintain standardized test protocols for cell formation, characterization, aging, reliability, and qualification, collaborating closely with cell engineers, manufacturing, and data science teams.
• Manage test data integrity and traceability by ensuring accurate data capture, metadata tagging, database integration, and alignment between manufacturing records and electrochemical test results.
• Lead troubleshooting and root-cause investigations of test hardware, sensors, environmental controls, data acquisition systems, and measurement anomalies to improve test accuracy, reproducibility, and operational efficiency.
• Support investigations of cell performance and quality variation, identifying and differentiating true cell-related issues from testing, equipment, instrumentation, or data-system anomalies.
• Support the definition and implementation of data schemas, naming conventions, and quality checks for battery test data, working with the database engineering team to ensure clean, structured, and ML-ready datasets.
• Manage the flow of test data from equipment to database systems, ensuring data completeness, proper metadata tagging (cell IDs, batch numbers, manufacturing lot traceability), and timely availability for analysis. Serve as the primary link between manufacturing records and electrochemical test results.
• Collaborate cross-functionally with Cell Development, R&D, Manufacturing, and Quality teams to ensure testing infrastructure and workflows meet evolving development needs.

Required Experience:

• Demonstrated experience installing, commissioning, and maintaining battery test equipment at scale, including cyclers, thermal chambers, and environmental test equipment.
• Hands-on expertise in calibration and metrology for electrochemical test systems, including voltage/current accuracy verification, thermocouple calibration, and environmental chamber qualification.
• Experience designing and building custom test fixtures and setups, including controlled-pressure, controlled-temperature, or instrumented cycling configurations with in-situ sensors for temperature, thickness, or pressure measurement.
• Strong understanding of battery test protocols, including formation, characterization (C-rate testing, HPPC, EIS), cycle life, and calendar aging procedures for lithium-ion cells.
• Experience managing test data pipelines: ensuring proper data capture from cyclers and auxiliary instruments, implementing metadata standards, and maintaining traceability between manufacturing records and test results.
• Proficiency with test equipment software and scripting environments for programming complex cycling protocols. Experience with data management tools (SQL, Python, or similar) for test data extraction and quality auditing.
• Experience managing vendor relationships for technical laboratory equipment, including procurement, installation oversight, service level agreements, and technical issue resolution.
• Strong troubleshooting and diagnostic skills: ability to identify and resolve issues in test hardware, sensing, data acquisition, and environmental control systems.
• Knowledge of chemical laboratory and battery testing safety practices, including safe handling and disposal of lithium-ion and lithium-metal cells.
• Excellent organizational skills with the ability to manage multiple testing programs, prioritize channel allocation, and maintain clear documentation in a high-throughput testing environment.
• Ability to excel in highly dynamic, early-stage environments; comfortable with evolving requirements, making progress despite incomplete information, and balancing immediate testing needs with longer-term infrastructure improvements.
• A high degree of professionalism, excellent communication, and presentation skills are essential. Must be comfortable working across experimental, manufacturing, and data science teams.

Requirements:

• A Bachelor’s or Master’s degree in engineering or the physical sciences, with 3+ years of hands-on experience in battery test engineering or a closely related role
• Candidates with an Associate’s degree or technical certification and extensive industry experience in battery test lab operations will also be considered.

Location & Benefits: San Leandro, CA. Full-time. $80,000-130,000. Salary and equity options dependent on experience. Dental, vision, healthcare and 401(k) benefits are included. Applications will be screened as received. 

Coreshell Technologies is an equal opportunity employer and does not discriminate on the basis of race, color, religion, sex (including pregnancy, gender identity, and sexual orientation), national origin, ancestry, age, disability, genetic information, military or veteran status, marital status, or any other protected status under California law.  

Applicants requiring reasonable accommodation during the application or interview process should notify the recruiting team.

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