Staff Mechanical Engineer

Expand Power Technologies, Inc.•Berkeley, CA

6d•$150,000 - $190,000•Onsite

About The Position

Expand Power is building solid-state transformers and modular power electronics for a decentralized, resilient grid. We're a small team doing hard, meaningful engineering, and we're just getting started. We’re backed by several Department of Energy programs, Berkeley National Laboratory, the Activate Fellowship, and world-class pre-seed investors and VCs. Our advisory network includes prominent leaders in power electronics, high frequency magnetics, the electric utility industry, and deep tech commercialization. We’re at a critical inflection point in the grid, where we have new sources and loads at a capacity that we couldn’t have dreamed of. Traditional grid electronics, with their lack of control and DC based capabilities, just can’t keep up. With real customer demand, we’re closing the gap between the grid of today and the grid of the future by building innovative smart transformers and modular power electronics. We’re excited to commercialize and deploy our technology across multiple customers for real world impact. We are growing the team and are looking for passionate, dedicated, ambitious hires who are excited by ownership and the modernization of our grid. This role is critical to Expand’s success– you will be working closely with the founders and first EE hires in the lab and in the field with real customers, reporting to the CEO. As our first ME hire, you will lead technical development of the mechanical design of our proprietary power electronics technology for immediate deployment. You will own the mechanical development of Expand’s DC-DC module– architecture, design, testing, and customer pilots. You will have a critical role in shaping the core technology, product direction, and culture of a cross-functional and rapidly growing early stage company. You’ll be one of the most valuable founding members of a company shaping the future of the electric grid. In doing so, you will push the limits of what’s achievable with renewable technology. The successful candidate can drive their own projects today and grow with the company into senior leadership roles.

Requirements

Highly experienced mechanical engineer, a master of your craft.
Enclosure design, thermal management, and packaging for power electronics is your bread and butter.
Proven track record of taking hardware from concept through production.
Hands-on experience with multi-physics simulation tools (CFD, thermal, structural) with a track record of using them alongside cost analysis to navigate trade offs, optimize, and inform system architecture decisions.
Deep expertise in mechanical engineering fundamentals, such as GD&T, finite element analysis, and designing for long-term reliability.
Mechanical and thermal design for high-power electronics (heat sink design, airflow management, cold plates, and/or liquid cooling).
Designing enclosures and housings for harsh or outdoor environments, including sealing, gasketing, corrosion resistance, and ingress protection.
Experience in startups or fast-paced, early stage company environments.
Bringing a hardware product from concept to market through design, test, deployment, and manufacturing while meeting certification standards and regulations (UL, IEC, etc.).
Fluency in typical mechanical engineering design tools, such as SolidWorks, Fusion 360, or Onshape, and simulation tools such as ANSYS, SimScale, or similar CFD/FEA packages.
Extensive hands-on time in the lab and shop — prototyping, instrumenting thermal tests, and iterating quickly on what the hardware tells you.

Nice To Haves

Packaging for medium-voltage power electronics
Busbar, laminated bus, and high-current interconnect design
Experience with EMI/EMC-driven mechanical design and shielding
DER, inverter, EV charging, or utility equipment product development
Knowledge of relevant industry standards (UL 1741, UL 50E, NEMA 250, IEC 60529, etc.)
Managing fabricators and contract manufacturers, including quoting, DFM feedback loops, and quality processes
Interacting and communicating with customers for development and deployment

Responsibilities

Leading the mechanical design and development of Expand's power electronics products, from the cabinet down to the board level, and in doing so, defining how next-generation power conversion hardware is packaged, cooled, and protected in the real world.
Owning the mechanical development cycle, including requirements definition, thermal and structural modeling, CAD design, prototyping, testing, and design for manufacturing.
Shaping the company's mechanical roadmap while navigating environmental, safety, and regulatory requirements.
Designing and developing enclosures, housings, and structural systems for medium-voltage power electronics, from first principles to test and validation to deployment for manufacturability and serviceability.
Conducting multi-physics simulations and optimizations to iterate on designs and validate them against demanding thermal, fluid, environmental, structural, and performance targets.
Building cost models and analyses to evaluate trade-offs and optimize manufacturability, from concept to production.
Owning the design, modeling, and analysis of electro-mechanical hardware, including heat sinks, insulation, magnetics, and mechanical enclosures for custom PCBAs.
Solving packaging challenges, like thermal management, vibration, and EMI.
Owning thermal management architecture, such as heat sinks, forced air, cold plates, and liquid cooling, for high-power-density converters and magnetics.
Simulating and modeling thermal, structural, and airflow behavior to maximize performance and reliability.
Designing for ingress protection, outdoor deployment, vibration, seismic, and transport requirements.
Conducting lab testing, validation, and debugging of prototype hardware, including thermal characterization under load.
Collaborating closely with power electronics engineers on component placement, busbar and interconnect design, creepage/clearance, and EMI shielding.
Documenting technical specifications, architecture decisions, and validation reports.
Driving design for manufacturing and assembly, working with external vendors.
Mentoring and guiding more junior engineers.
Collaborating on IP generation.