Mechanical Engineer II

Proper Voltage•Carlsbad, CA

1d•Onsite

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 looking for an early-career mechanical engineer who is eager to grow in battery pack design and wants to develop hands-on skills in a fast-moving hardware environment. You'll work alongside senior engineers on real battery systems — contributing to CAD, testing, analysis, and manufacturing support from day one. An interest or academic background in thermal analysis is a strong plus. We run active thermal test campaigns and simulation workflows, and this role is a great entry point for someone who wants to build depth in that area.

Requirements

Bachelor's degree in Mechanical Engineering or closely related discipline
0–3 years of professional mechanical engineering experience (internships and co-ops count)
Proficiency in 3D CAD (Onshape, SolidWorks, or equivalent) — coursework projects are fine
Understanding of engineering fundamentals: materials, statics, GD&T basics, tolerancing
Ability to read and produce engineering drawings
Strong attention to detail and willingness to learn in a hands-on environment

Nice To Haves

Coursework or project experience in heat transfer, thermodynamics, or thermal systems
Any exposure to FEA or CFD tools — even academic (SimScale, ANSYS, SolidWorks Simulation)
Experience with battery-powered devices, EV systems, or energy storage in any context
Exposure to manufacturing processes — machining, sheet metal, plastics, assembly
Familiarity with UN 38.3 or UL safety standards (awareness, not expertise)
Experience supporting a physical prototype build from CAD to assembled hardware

Responsibilities

Support mechanical design of battery modules and packs under direction of senior engineers, including: Cell integration concepts (prismatic, cylindrical, or pouch formats), Structural components, brackets, and enclosure details, Busbar and interconnect geometry
Create and maintain CAD models and drawings to support design reviews and prototype builds
Assist with tolerance stack-up analysis and DFM reviews
Help define and document mechanical interfaces across the assembly
Support thermal simulation setup and post-processing under guidance (SimScale, ANSYS, or equivalent)
Assist in evaluating TIM and interface materials — compile data sheets, summarize properties, and support comparison analyses
Help log and organize thermal test data from discharge campaigns and flag trends for senior review
Learn to correlate simulation outputs to physical test results
Support execution of mechanical validation tests — vibration, drop, thermal cycling
Assist with data collection, documentation, and test reports
Help track open issues from test findings and follow up on corrective actions
Support prototype builds — attend build sessions, document assembly steps, flag fit/finish issues
Assist with fixture and tooling documentation
Communicate with vendors and CMs under direction to gather quotes, lead times, and capability data
Maintain clean CAD revision history and BOM entries
Write and update engineering documentation, test procedures, and work instructions
Contribute to design review materials and action item tracking