Staff Mechanical Engineer — Thermals, BESS

About the Role

As a Staff Mechanical Engineer Thermals you will drive thermal architecture cooling strategy and safety design for utility-scale Battery Energy Storage Systems (BESS) spanning outdoor cabinets and containerized platforms. You will design Chiller-based liquid-cooled air-cooled and hybrid thermal systems that support multi-MWh energy storage installations operating in demanding outdoor environments.

This role requires hands-on expertise in thermal system design advanced simulation and BESS safety compliance. You will work closely with inverter mechanical electrical controls systems safety and manufacturing teams to ensure thermal solutions meet performance reliability manufacturability serviceability compliance and cost targets delivering production-ready designs from concept through deployment while optimizing CAPEX and long-term OPEX.

What You Will Do

• Drive thermal architecture cooling strategy and safety design for cabinet-level and containerized BESS platforms from concept through production and field deployment.
• Design Chiller-based liquid-cooled air-cooled and hybrid thermal systems for power electronics including heat exchangers chillers cooling plates pumps valves manifolds fans ducting and venting devices.
• Apply first-principles thermal engineering to design efficient reliable and cost-effective cooling solutions.
• Perform system-level and detailed thermal and CFD analysis and translate results into production-ready compliant designs.
• Lead arcing analysis containment design with sensors venting pressure-relief mechanisms and propagation-mitigation strategies.
• Drive DFMEA root-cause analysis and corrective actions based on test data and field feedback.
• Support supplier selection and technical design reviews balancing performance reliability manufacturability and cost (CAPEX/OPEX).
• Support certification efforts and AHJ interactions across global safety and compliance standards.
• Provide technical guidance and mentor junior engineers.

Who You Are and What you Bring

• Bachelors or Masters in Mechanical or Thermal Engineering with 8 years of hands-on experience including experience with utility-scale BESS thermal architectures.
• Strong proficiency in thermal and CFD simulations system-level and detailed analysis including airflow and system-flow simulations and transient and steady-state thermal analysis using tools such as Icepak Fluent COMSOL and FLACS.
• Experience translating simulation results into production-ready compliant designs including analyses supporting NFPA 68 (deflagration venting) and NFPA 69 (explosion prevention).
• Experience with arcing analysis containment design with sensors venting pressure-relief mechanisms and propagation-mitigation strategies.
• Strong system-level understanding of PCS architectures battery rooms DC- vs. AC-coupled systems and thermal coordination with BMS EMS and PCS derating logic.
• Demonstrated capability designing for high-ambient (4555 C) high-altitude corrosive environments and long-duration (28 hour) energy storage systems.
• Experience with reliability-driven thermal design including 1525-year system-life targets redundancy fail-safe and degraded-mode operation and OPEX-optimized cooling strategies.
• Experience driving DFMEA root-cause analysis and corrective actions based on test data and field feedback.
• Experience supporting supplier selection and technical design reviews balancing performance reliability manufacturability and cost (CAPEX/OPEX).
• Working knowledge of global safety and compliance standards including UL 9540/9540A NFPA 855/68/69 and IEC standards with experience supporting certification and AHJ interactions.
• Technical leadership skills with the ability to lead projects influence design decisions and mentor junior engineers.

Work Location

This role requires being on-site at our Austin Texas office 5 days per week.

The base pay range for this position is $100000 to $151000 per year. This salary range may be modified in the future. The successful candidates starting pay will be determined based on job-related skills experience education or training work location and market conditions. This position is also eligible for bonus equity and benefits.