Mechanical Engineer - Cell Stack

Electroflow is unlocking domestic production of lithium iron phosphate (LFP), the battery material that will power an energy-abundant future. Using our proprietary electrochemical process, we collapse an incumbent 10-step brine-to-LFP supply chain into just three, making us on track to produce the lowest-cost LFP on the planet. After raising a $10 million Seed round backed by Union Square Ventures and Voyager Ventures, and being featured in The Wall Street Journal (twice!) and TechCrunch, we’re scaling fast to build America’s largest fully domestic LFP supply chain!

As a Mechanical Engineer - Cell Stack, you’ll lead the design, build, and deployment of Electroflow’s modular electrochemical stack. The core hardware that drives our lithium extraction technology. You’ll take ownership of stack architecture, sealing systems, and manufacturability, collaborating closely with our electrochemistry, process, and manufacturing teams. This is a hands-on, full-ownership role for a builder who thrives on turning complex mechanical systems into robust, field-ready hardware.

• Own the stack. Lead design of our electrochemical cell stack (frames, manifolds, compression systems, and sealing interfaces) from concept through field deployment.
• Drive development. Partner with internal teams and external suppliers to balance performance, manufacturability, cost, and reliability.
• Prototype and test. Design and build prototypes; run flow, pressure, and sealing tests; iterate fast based on data and field feedback.
• Scale and transfer. Work with manufacturing and technical operations to transition from prototype to pilot to production, including DFM/DFMA, tolerance analysis, and documentation.
• Integrate and deploy. Support system integration, installation, and commissioning of containerized or modular field systems.
• Ensure quality and reliability. Set specifications, define test plans, and feed lessons learned from field data back into next-generation designs.

Requirements

We’re looking for a mechanical engineer who’s taken complex fluid or electrochemical hardware from prototype to production. Someone who can own design decisions and ship real systems that work.

You’ll do great here if you have:

• A Bachelor’s or Master’s degree in Mechanical, Manufacturing, or Electrochemical Engineering (or equivalent experience).
• 5 years of experience designing and deploying high-reliability mechanical or electrochemical systems (battery, fuel-cell, electrolyzer, or process hardware).
• Expertise in sealing systems: O-rings, gaskets, compression hardware, and frame stiffness management.
• Manufacturing fluency: CNC machining, polymers/elastomers, coatings, corrosion selection, and GD&T.
• Familiarity with process piping, manifolds, and packaging for industrial or containerized systems.
• Hands-on prototyping skills: you’re comfortable with tools, test setups, and getting data fast.
• Strong fundamentals in mechanical design, tolerance analysis, and structural integrity.
• Clear communication, organized documentation, and cross-disciplinary collaboration skills.

Bonus points if you:

• Have experience with large electrochemical stacks or flow batteries.
• Bring familiarity with electrochemistry, ion-exchange, or membrane-based systems.
• Have led field installs or commissioning for process or mobile hardware.
• Know your way around SolidWorks or similar CAD/PDM tools, and basic FEA/CFD analysis.

You'll fit right in if you:

• Love building new hardware from the ground up and making it reliable at scale.
• Thrive in a fast-moving, collaborative, startup environment.
• Care deeply about sustainability, reshoring, and American clean-tech manufacturing.
• Take full ownership, from CAD to commissioning.

Benefits

• Build and support cutting-edge technology with a driven, mission-oriented team.
• Health Care Plan (Medical, Dental & Vision)
• Retirement Plan (401k, IRA)
• Life Insurance (Basic, Voluntary & AD&D)
• Paid Time Off (Vacation, Sick & Public Holidays)
• Stock Option Plan