Mechanical Engineer

Expand Power is building solid-state transformers and modular power electronics for a decentralized, 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.

You will be 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. You'll own the mechanical development cycle, including requirements definition, thermal and structural modeling, CAD design, prototyping, testing, and design for manufacturing.

You'll shape the company's mechanical roadmap while navigating environmental, safety, and regulatory requirements.

You'll also use creativity and innovation to:

• Design and develop enclosures, housings, and structural systems for medium‑voltage power electronics, from first principles to test and validation to deployment for manufacturability and serviceability
• Conduct multi‑physics simulations and optimizations to iterate on designs and validate them against demanding thermal, fluid, environmental, structural, and performance targets
• Build cost models and analyses to evaluate trade‑offs and optimize manufacturability, from concept to production
• Own the design, modeling, and analysis of electro‑mechanical hardware, including heat sinks, insulation, magnetics, and mechanical enclosures for custom PCBAs
• Solve packaging challenges, like thermal management, vibration, and EMI
• Own thermal management architecture, such as heat sinks, forced air, cold plates, and liquid cooling, for high‑power‑density converters and magnetics
• Simulate and model thermal, structural, and airflow behavior to maximize performance and…