Thermal Design Engineer

Position: Staff Thermal Design Engineer
About Rivian Rivian is on a mission to keep the world adventurous forever. This goes for the emissions-free Electric Adventure Vehicles we build, and the curious, courageous souls we seek to attract. As a company, we constantly challenge what's possible, never simply accepting what has always been done. We reframe old problems, seek new solutions and operate comfortably in areas that are unknown.

Our backgrounds are diverse, but our team shares a love of the outdoors and a desire to protect it for future generations. Role Summary Thermal design and validation of low-voltage electrical hardware is a mission-critical function at Rivian, ensuring the long-term reliability and performance of our core electronic control units (ECUs) in the most demanding vehicle environments. In this role, you will lead the development of high-fidelity thermal strategies for our in-house ECU portfolio-bridging the gap between silicon-level performance and vehicle-level environmental integration.

You will be responsible for owning the "digital-to-physical" loop, from chip/package-level modeling to system-wide steady-state and transient simulations. By establishing the "gold standard" for simulation-to-test correlation, you will ensure our hardware survives rigorous thermal cycling and AEC-Q reliability standards. This role involves pushing the boundaries of electronic packaging-optimizing thermal stack-ups, TIM interfaces, and PCB-to-chassis heat pathways-to ensure our vehicle electronics achieve industry-leading efficiency, minimal mass, and mission-critical thermal reliability.

Responsibilities Lead thermal strategy, conceptualize designs, and perform numerical simulations to address complex thermal challenges for leading-edge vehicle electrical hardware. Develop electronic cooling and packaging solutions for next-generation vehicle architectures and electronic systems. Define and support CFD workflows. Perform detailed steady-state and transient simulations-ranging from chip/package-level and PCB-level to full-system integration-as well as Board Level Reliability (BLR) analysis to drive design optimization for high-power thermal requirements.

Establish simulation-to-test correlation methodologies. Build physical mockups, manage thermocouple instrumentation, and execute extensive chamber testing to validate and refine digital models. Define and execute board-mounting and heat-sinking strategies for LV systems. Optimize PCB layout, via density, and thermal pathways to the chassis to ensure component junction temperatures remain within derating limits. Provide detailed, actionable design feedback-including thermal stack-ups, cooling layouts, and material selections-to engineering teams responsible for vehicle electronics design.

Analyze the impact of the under-hood vehicle environment on low-voltage electronics and define design requirements that account for real-world environmental stressors. Develop strategies for optimizing thermal and mechanical components by minimizing mass, cost, and material usage. Drive the characterization and selection of thermal hardware, including blowers, fans, heat pipes and heat sinks, utilizing advanced airflow measurement techniques to verify system performance.

Author detailed technical documentation, present simulation results to cross-functional stakeholders, lead trade-off studies, and provide expert support for reliability qualification and product readiness milestones. Provide actionable design suggestions regarding thermal stack-ups, Thermal Interface Material (TIM) selection, assembly tolerances, and stack preload to identify and mitigate long-term thermal reliability risks. Coordinate and work with cross-functional analysts to align on analysis methodologies and design constraints.

Own and drive thermal methodologies, deliverables, and test specifications to support modeling efforts. Work in multidisciplinary teams to drive product and engineering excellence. Qualifications

Education & Experience:

Master's degree in Mechanical or Thermal Engineering (or equivalent) with 6-8+ years or PhD in Mechanical or Thermal Engineering (or equivalent) 4-6+ years of relevant industry experience in providing electronic cooling solutions, including thermal layout, heat sink design, fan/blower development, and characterization of Thermal Interface Materials (TIMs). Advanced Simulation Suite:
Expert-level proficiency in industry-standard CFD and thermal analysis tools, including Ansys Icepak (Classic & EDT), Fluent, Flotherm, and Star-CCM+. Advanced competency in pre-and post-processing software-specifically ANSA and META-for geometry simplification, high-fidelity meshing, and data visualization. Component-to-System Modeling:

Experience with chip and IC package-level thermal modeling is highly preferred, demonstrating an understanding of heat transfer from the silicon junction through the board stack-up. Hands-On Validation:
Proven experience with thermal prototype builds, thermocouple instrumentation, data…