Senior Mechanical Design Engineer

ABOUT BRELLE   ENERGY FOR WHAT MOVES US. Brelle is a venture-backed technology company building the next generation of energy and powertrain systems for the world’s most demanding machines. Our team comes from companies like Rivian, SpaceX, and McLaren, bringing deep expertise in high-performance engineering, electrification, and advanced manufacturing. Brelle develops frontier technology that pushes what’s possible in electrified performance. Based in California, we develop next-generation energy and powertrain technology for supercars and superbikes, working alongside leading high-performance brands across the U.S. and Europe. Our innovations are built on a novel pack architecture, a full-stack software platform, and an advanced approach to automated production. Joining Brelle means working on technology that makes the world’s most demanding vehicles and aircraft lighter, safer, more engaging, and capable of charging in minutes. Our engineering teams operate like small Skunkworks teams: nimble, cross-functional, and highly technical. Engineers are encouraged to explore new concepts and materials, move quickly from concept to prototype, and have significant autonomy to develop, validate, and release their work across programs. We’re building something ambitious in a highly competitive market, and the bar is high. We need people who are exceptional at what they do, take real ownership, and are willing to do what the moment requires. ABOUT THE ROLE As a Senior Mechanical Design Engineer, you'll own the design and development of battery module components from concept through production. You'll work across cell retention, thermal management, safety systems, housing integration, and electromechanical interfaces, partnering closely with electrical, thermal, simulation, and software teams to optimize the complete battery pack and vehicle package. This is a hands-on, high-ownership role where you'll be expected to make sound design decisions, solve complex problems, and drive your work forward with a high degree of autonomy. WHAT YOU'LL DO - Own the design for a new module architecture— cell retention systems, thermal management strategies, safety systems, housing integration, and electromechanical interfaces - Work with cylinder and pouch cell formats in 400-1000V systems, optimizing weight, thermal performance, cost, and manufacturing feasibility - Collaborate cross-functionally with Brelle’s electrical, thermal, simulation, and software teams to optimize the complete battery pack package - Coordinate design work with pack team members to converge on feasibility for function, manufacturing, and reliability of modules in pack and vehicle - Develop a robust cell venting strategy and propagation protection while meeting manufacturing and cost targets - Identify and suggest missing requirements needed and drive completion of released requirements WHAT WE'RE LOOKING FOR - Bachelor's or master's degree in mechanical engineering (or equivalent with demonstrated depth) - 5+ years of mechanical design experience in automotive or motorcycle battery/powertrain development - Advanced CAD proficiency in CATIA V5/V6 (3DX), NX, or SolidWorks: complex assemblies, GD&T, production drawings - Robust understanding of lithium-ion cell as it relates to electromechanical and safety design constraints - Understanding of battery system architectures and HV safety requirements (400V+ systems) - Hands-on structural FEA experience: defining load cases, boundary conditions, interpreting results for design decisions - Experience with DFM for multiple processes: injection molding, stamping, casting, composites, machining, fabricating - Experience with DFMEA/DVP&R cycles and design release processes - Battery module or pack design experience—you've navigated cell-level constraints and thermal management complexity PREFERRED QUALIFICATIONS - Practical hands-on experience in professional or personal projects – interest in working directly on the parts/products in the lab - Thermal simulation experience (CFD or equivalent)—you understand heat transfer, material selection implications and can develop solutions to meet system-level requirements - Design experience integrating into vehicle platforms—you understand powertrain architecture and integration challenges - Experience working at or with automotive OEMs or Tier-1 Suppliers on electrified platforms. - Proven track record releasing components to production: you've worked in a high-pace environment, participated in design reviews, and understand how designs move from concept to production level parts YOU ARE... Exceptional at what you do — You have a track record of doing excellent work, solving difficult problems, and raising the bar for the people around you. We're a small team, and we need people who can operate at a very high level without needing a lot of direction. An Owner — You take responsibility for outcomes, not just tasks. You see what needs to happen, make decisions, and drive problems through to completion. Curious and Rigorous — You dig into hard problems, reason from first principles, and care about getting to the right answer—not just the fastest answer. High Standards, Low Ego — You care deeply about technical excellence while being collaborative, direct, humble, and good to the people around you. You make the team better, not just yourself. Willing to Lean In — We're building a company in a highly competitive market, and we're still proving ourselves. Most weeks should be sustainable, but there will be moments when the company needs us to sprint. When the moment matters, we expect people to step up, take ownership, and show up for the team. COMPENSATION & BENEFITS Base Salary: $140,000 - $175,000 Meaningful equity participation through Brelle's Employee Incentive Plan. - Medical, dental, and vision (HMO/PPO) - 401(k) - Flexible PTO - Team meals twice a week - Monthly team events Build something exceptional. Own your work. See it move.