Mechanical Engineer III - Battery Systems
About The Position
Proper Voltage is unlocking the next generation of battery technology across robotics, data centers, and defense. We're building intelligent battery systems that make advanced chemistries (sodium-ion, lithium-titanate, lithium-silicon) work in products that were never designed for them. Humanoid robots can upgrade power systems without redesigning their entire platform. Data centers get safer, cheaper backup power. Drones and autonomous vehicles get higher energy density without lengthy integration cycles. If you want to work on hard engineering problems that matter — this is the place. We are seeking a mechanical engineer with hands-on battery pack experience to contribute to the design, testing, and validation of battery modules and packs. This role is well-suited for an engineer who has worked on battery systems through the prototype and early production phases and is looking to grow their depth in thermal management, certification compliance, and systems integration. Thermal analysis experience is a strong plus — we work on demanding discharge profiles and actively developing TIM selection processes, SimScale simulation workflows, and in-house thermal test campaigns.
Requirements
- Bachelor's degree in Mechanical Engineering or related discipline
- 3–5 years of experience in a mechanical engineering role, with meaningful exposure to battery pack or energy storage product development
- Experience with CAD tools (Onshape, SolidWorks, or equivalent)
- Working knowledge of structural and mechanical design principles (stack-ups, tolerances, enclosures)
- Working knowledge of thermal management fundamentals in high-density electronics or battery systems
- Working knowledge of basic FEA or simulation concepts (structural or thermal)
- Familiarity with battery safety and compliance frameworks (UN 38.3, UL 1973, or similar)
- Ability to interpret and act on test data — you close the loop between simulation and hardware
Nice To Haves
- Hands-on thermal simulation experience (SimScale, ANSYS Icepak, Fluent, or equivalent)
- Experience characterizing or selecting TIM materials (thermal resistance, bond line, adhesion)
- Exposure to UN 38.3 or UL 1973 test preparation or documentation
- Experience with sodium-ion, lithium-ion, or LTO cell formats in pack-level applications
- Familiarity with IEC 62619 or other international battery standards
- Experience supporting DFM discussions with contract manufacturers
Responsibilities
- Support mechanical design of battery modules and packs, including cell integration (prismatic, cylindrical, or pouch formats), structural stack-ups and compression/retention systems, industrial and rack-mounted enclosure design, and busbar and high-current interconnect geometry.
- Assist in defining mechanical strategies for shock, vibration, and environmental durability.
- Contribute to thermal management solutions, including passive heat plates, TIM selection, airflow layout, and fan integration.
- Run and interpret thermal simulations (SimScale, ANSYS, or equivalent CFD/FEA tools).
- Support TIM and interface material evaluation — compare materials across thermal resistance, adhesion, and manufacturability criteria.
- Analyze thermal test data from discharge campaigns (2C, high-watt scenarios) and identify hotspot patterns.
- Correlate simulation results to physical test data and iterate on design accordingly.
- Support mechanical preparation for UN 38.3 transport testing, UL 1973 battery system certification, and UL 9540 / 9540A (as applicable).
- Translate certification requirements into design constraints — creepage/clearance, enclosure integrity, protection strategies.
- Assist in documentation and test preparation for third-party lab submissions.
- Contribute to mechanical validation plans covering vibration, drop, thermal cycling, and abuse scenarios.
- Support root cause analysis during environmental and safety testing.
- Apply test findings to iterate on design robustness.
- Apply DFM principles during early design — tolerance stack-ups, assembly sequence, fixture considerations.
- Collaborate with cross-functional teams during prototype builds and controlled production releases.
Benefits
- Equity participation as part of total compensation
- Comprehensive healthcare benefits (medical, dental, vision)
- Paid time off and company holidays
- Opportunity to grow into a senior technical role on a platform that is shaping next-generation energy storage
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What This Job Offers
Job Type
Full-time
Career Level
Senior
