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Brelle

Software-defined, modular EV battery systems

Staff Mechanical Design Engineer

Full-Time
$160k - $185k+ Equity participation
Senior, Expert
Bachelor's, Master's
Los Alamitos, CA, USA
In Person
Mechanical EngineeringDesign Engineering

About the job

Requirements
  • A bachelor's or master's degree in mechanical engineering, or equivalent experience demonstrating depth.
  • 7–8+ years of mechanical design experience in automotive or motorcycle battery or powertrain development.
  • Advanced proficiency with CATIA V5/V6 (3DX), NX, or SolidWorks for complex assemblies, geometric dimensioning and tolerancing, and production drawings.
  • Robust understanding of lithium-ion cells and their electromechanical and safety design constraints.
  • Understanding of battery system architectures and high-voltage safety requirements for 400V+ systems.
  • Hands-on structural finite element analysis experience, including defining load cases and boundary conditions and interpreting results to inform design decisions.
  • Experience with design for manufacturing for multiple processes, including injection molding, stamping, casting, composites, machining, and fabrication.
  • Experience with design failure mode and effects analysis, design verification plan and report cycles, and design release processes.
  • Battery module or pack design experience involving cell-level constraints and thermal management complexity.
Responsibilities
  • Own the design and development of battery module components from concept through production.
  • Own the design of a new module architecture, including cell retention systems, thermal management strategies, safety systems, housing integration, and electromechanical interfaces.
  • Work with cylindrical and pouch cell formats in 400–1000V systems, optimizing weight, thermal performance, cost, and manufacturing feasibility.
  • Collaborate with electrical, thermal, simulation, and software teams to optimize the complete battery pack package.
  • Coordinate design work with pack team members to converge on functional, manufacturing, and reliability feasibility for modules in the pack and vehicle.
  • Develop a robust cell venting strategy and propagation protection while meeting manufacturing and cost targets.
  • Identify missing requirements and drive completion of released requirements.
Desired Qualifications
  • Practical hands-on experience in professional or personal projects, with interest in working directly on parts or products in the lab.
  • Thermal simulation experience, including computational fluid dynamics or equivalent; understanding heat transfer and material selection implications and developing solutions that meet system-level requirements.
  • Experience integrating designs into vehicle platforms, including understanding powertrain architecture and integration challenges.
  • Experience working at or with automotive original equipment manufacturers or Tier 1 suppliers on electrified platforms.
  • A track record of releasing components to production, participating in design reviews, and understanding how designs progress from concept to production-level parts.

About the company

Brelle designs and builds advanced battery systems for electric vehicles, including lightweight, modular packs and software-defined powertrains optimized for ultra-fast charging. Its products run on Brelle OS, a software layer that handles safety-critical functions, diagnostics, and over-the-air updates, with AI-based software that optimizes performance and safety. The modular architecture fits multiple vehicle platforms and can achieve high cell-to-pack efficiency, including a recent collaboration with Enevate to enable about 4C charging. The goal is to improve drivetrain efficiency and performance by delivering scalable, software-managed battery systems and powertrains that support rapid charging across EV platforms.

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Total Funding

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Headquarters

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Founded

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Simplify Jobs

Simplify's Take

What believers are saying

  • Automotive Ventures backed Brelle in 2025, validating early investor confidence.
  • June 2026 engineering hiring shows active execution across firmware, mechanical, and programs.
  • Brelle.tech and Ashby postings indicate ongoing development, not a dormant prototype shop.

What critics are saying

  • Brelle still lacks a public production customer, shipment, or revenue announcement.
  • Enevate can license elsewhere, leaving Brelle without proprietary cell advantages by 2027.
  • Heavy Los Alamitos hiring signals burn; a missed 2026 raise risks shutdown.

What makes Brelle unique

  • Brelle pairs software-defined battery packs with Brelle OS and OTA diagnostics.
  • The April 2025 Enevate collaboration validated 4C charging and 85% cell-to-pack efficiency.
  • It targets supercars and superbikes, where extreme fast-charging beats commodity EV suppliers.

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Benefits

  • Health Insurance
  • Dental Insurance
  • Vision Insurance
  • Unlimited Paid Time Off
  • Company Equity

Company News

Refactor Capital
Oct 9th, 2026
Brelle: the energy platform for the world's most demanding machines.

Brelle: the energy platform for the world's most demanding machines. Brelle is a Los Angeles hard tech company building integrated battery systems and embedded software for automotive, motorcycles, and aerial and defense platforms. Founder Martin Hermez spent seven years at Rivian leading energy systems and software teams. I'm proud that Refactor Capital is backing Brelle, alongside Timescale, with a board that includes Charles Sanderson, former Chief Engineer at Rivian and CTO of McLaren Automotive. A founder who has seen the whole arc. Martin was born in Iraq, into a Chaldean family. After the 2003 Iraq War, his family fled the warzones of Baghdad and resettled in Detroit. He learned English there, adapted to a new country, and fell for technology, cars, and software. That path led him to Rivian, where he was one of the earliest engineers. Over seven years he led energy systems and software teams through the full arc, from prototype to mass production of Rivian's launch products. Very few people get to live through that, and fewer still come out the other side knowing exactly what they would do differently. Brelle is what Martin would do differently. The scale-up lessons are baked in from day one instead of bolted on at Series C. One platform, many machines. Most battery companies design a pack for a product. Brelle designs a flexible battery architecture and then deploys it across segments at the same time. Today that means three starting points. * Automotive. High-density battery systems for next-generation performance vehicles, built for strong power-to-weight efficiency and fast charging. * Motorcycles. A lightweight, compact energy architecture for machines where agility matters, tuned for power density and thermal resilience under sustained load. * Air and defense. Battery platforms for high-output, weight-sensitive aerial applications, including drones and advanced air mobility, where reliability is the whole job. These machines look different, but they ask the same thing of their energy system: a lot of power, very little weight, and no surprises. One architecture that serves all of them is a stronger bet than three separate pack programs. Hardware and software built as one system. The part of Brelle I find most interesting is that the battery and the software are designed together. Brelle's flexible battery hardware is tightly coupled with Brelle OS, an embedded software platform, plus the tooling around it. The result is a system that is adaptive, extensible, and performant, and one that is low friction for the customers who build on it. This is the deep tech version of owning the stack. When the team controls the cells, the pack, the firmware, and the tools, they can tune the whole system instead of negotiating between vendors. Brelle also builds safety in as layers, from materials through software, rather than treating it as a final test. US-first supply chain, designed for dark-factory automation. Brelle is planning its manufacturing strategy before it needs it. The supply chain is US-first, and the product is designed from the start for dark-factory automation, meaning factories that run with minimal human intervention. The goal is globally competitive scale economics from an American supply chain. That is a hard problem and an important one for frontier tech and critical industries. Batteries are the energy backbone of electrified vehicles, drones, and defense systems, and the country needs more than one credible domestic answer. Designing for automation up front is how a seed-stage company gets a shot at competing on cost with the best manufacturers in the world. Martin has watched what happens when manufacturing is an afterthought, and he is not repeating it. A team from the places that set the bar. Brelle's team includes alumni from Rivian, Tesla, Koenigsegg, Apple, and McLaren, among others. That mix of automotive, hypercar, consumer hardware, and motorsport experience shows in how the company talks about performance. The company tests at the HiMaC facilities at UC Irvine, and the work is hands-on, in the lab and on the line. Charles Sanderson's involvement on the board matters to me as well. He has taken vehicles from engineering concept to customer hands at both Rivian and McLaren, and he knows what it takes to ship hardware at that level. Why I backed brelle. At Refactor, I look for founders who have earned the right to take on a hard problem. Martin has. He learned his craft at one of the few American companies to take a new vehicle platform from prototype to mass production, and he left with a clear view of where the energy system becomes the bottleneck. I like the platform approach because it respects how hard tech actually works. You do not get unlimited shots, so you build one architecture that can serve several markets. I like the integrated stack because the best battery in the world is only useful if the software around it is excellent. And I like the manufacturing plan because it was written by someone who has watched a factory ramp. If you are building a machine that asks a lot of its battery, whether that is a vehicle, a motorcycle, or an aircraft, Brelle would like to hear from you. You can learn more and start a project at brelle.tech. Congratulations to Martin and the whole Brelle team. A long way from Baghdad to Detroit to Los Angeles, and they are just getting started. #BetterCallZal