Staff Mechanical Engineer — Thermals, BESS

DescriptionEnphase Energy is a global energy technology company and a leading provider of solar, battery, and electric vehicle charging products. Founded in 2006, our innovative microinverter technology revolutionized solar power, making it a safer, more reliable, and scalable energy source. Today, the Enphase Energy System enables users to make, use, save, and sell their own power. Enphase is also one of the most successful and innovative clean energy companies in the world, with more than 80 million products shipped across 160 countries. Join our dynamic teams designing and developing next-gen energy technologies and help drive a sustainable future!About the RoleAs 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 DoDrive 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 BringBachelor's or Master's 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 (45–55 C), high-altitude, corrosive environments, and long-duration (2–8+ hour) energy storage systems.Experience with reliability-driven thermal design, including 15–25-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 LocationThis role requires being on-site at our Austin, Texas office 5 days per week.The base pay range for this position is $100,000 to $135,000 per year. This salary range may be modified in the future. The successful candidate’s 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.