---
title: 'Junior Product Design Engineer at Stealth-mode Battery Startup'
canonical: 'https://feeny.ai/job/junior-product-design-engineer-stealth-mode-battery-startup-san-jose-w90m818snnpr'
type: 'job'
last_seen: '2026-09-10'
---

# Junior Product Design Engineer at Stealth-mode Battery Startup

- **Company:** Stealth-mode Battery Startup
- **Location:** San Jose, CA
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-07-01
- **Last confirmed live:** 2026-09-10
- **Apply:** https://jobs.ashbyhq.com/company/8e03652d-79fe-4669-b859-67a0efa4c94b

## Job description

## About the Company

We are a stealth-mode battery startup developing cutting-edge battery technology. Our mission is to revolutionize battery technology to accelerate the global transition to clean energy. By leveraging innovative materials and advanced manufacturing techniques, we are building the future of sustainable energy.

Can’t find the company name? It’s not you, it’s us! We’re really excited about the potential of our technology, product, and mission, and have chosen to remain in stealth mode. If the job description piques your interest, please apply. If your skillset is aligned with what we’re looking for, the team will reach out to schedule your interview and tell you a bit more about us (e.g. who we are).

## Role

We are seeking a Mechanical Design Engineer to support the design and development of structural battery hardware (e.g., enclosures, trays, lids/covers) and/or provide engineering support equipment (fixtures, test-bucks, test setups, and prototype/demo manufacturing equipment).

You’ll work closely with senior engineers and cross-functional partners (analysis, test, manufacturing) to translate concepts into hardware that meets performance, reliability, and manufacturability needs.

## Responsibilities

Mechanical Design & Product Development

- Support design of structural components for HV battery packs such as enclosures, trays, covers, and related brackets/interfaces under thermal, mechanical, and environmental constraints
- Create and iterate 3D CAD models and assemblies; contribute to design trades (weight, stiffness, cost, manufacturability) with guidance from senior engineers.
- Apply DFM/DFA fundamentals in part and assembly design (fasteners, sealing concepts, stack-ups, serviceability).
- Produce 2D drawings with clear notes, basic GD&T, and manufacturing intent; support tolerance studies as needed.
- Provide directional guidance through simulations to steer the design and architecture when dedicated CAE resources are limited.
- Develop comprehensive 2D drawing packages applying appropriate GD&T and conduct tolerance analyses to ensure assembly integrity and performance.

Fixtures, Bucks, and Prototype/Test Equipment

- Design and develop fixtures, bucks, test setups, and prototype/demo pack manufacturing equipment to support proof-of-concept builds and validation.
- Help maintain and improve existing fixture designs (updates, repairability, usability, documentation).
- Work with standard fixturing components and vendor catalogs; select appropriate hardware and mechanisms.

Hands-On Build Support & Collaboration

- Partner with manufacturing/shop resources during fabrication, prototype builds, and assembly debug—bringing a “design it, build it, improve it” mindset.
- Coordinate with suppliers for quotes, DFM feedback, and part delivery; assist with incoming inspection and fit/function checks.
- Support test activities (vibration/structural/environmental) and document findings; assist in root-cause investigations and corrective actions.

Validation & Testing

- Support component and system-level validation, including vibration, structural, and environmental testing.
- Support in validation, durability, and abuse testing activities to ensure performance and reliability.
- Drive root-cause analysis and corrective actions for mechanical performance issues.

## Qualifications

- B.S. in Mechanical Engineering (or related), or a technical diploma in Mechanical Technology/CAD with equivalent hands-on experience.
- 3+ years of mechanical design experience (product, structures, automation equipment, fixtures, or custom machinery).
- Proficiency in 3D CAD (SolidWorks, Inventor, NX, CATIA, or similar).
- Experience producing 2D drawing packages; familiarity with GD&T concepts and tolerance stack-up basics.
- Working knowledge of fabrication/manufacturing methods (machining, sheet metal, welding, fastening, bonding) and how they influence design decisions.
- Comfortable in fast-paced, iterative development environments; strong communication and documentation habits.

## Preferred Qualifications

- Experience with HV battery systems and structural designs (or adjacent structural systems like automotive body/chassis).
- Familiarity with manufacturing processes such as machining, injection molding, 3D printing, and extrusions.
- Exposure to FEA/structural analysis tools (ANSYS, Abaqus, LS-DYNA, etc.) at a basic level (interpretation/collaboration vs. ownership).
- Knowledge of design release workflows for mechanical parts and assemblies.
- Comfort working with electro-mechanical designs.

Why Join?

- Innovative Technology: Work on cutting-edge energy storage solutions that power the future.
- Career Growth: Opportunities to work on high-impact projects and advance in a growing industry.
- Competitive Benefits: Comprehensive health, wellness, and professional development programs.
- Mission-Driven Culture: Be part of a team that is shaping the future of sustainable energy through innovation and excellence.

## About Stealth-mode Battery Startup

## Company Overview
- **One-liner**: A stealth-mode startup developing next-generation battery technology to accelerate the global transition to clean energy.
- **Entity Type**: Private (Stealth-mode startup)
- **Headquarters**: San Francisco Bay Area, California, United States
- **Founded**: Not publicly available
- **Founders**: Not publicly available

## Core Business
- Primary industry/industries: Battery Manufacturing, Energy Technology, Clean Energy
- Target customers: B2B (likely automotive, energy storage, or consumer electronics manufacturers)
- Mission or purpose statement: "Revolutionize battery technology to accelerate the global transition to clean energy."

## Market Standing
- **Valuation**: Not publicly available (stealth-mode startup)
- **Key Metric**: Total Funding — Not disclosed; company is currently hiring for multiple roles, suggesting active fundraising or prior funding.
- **Notable Investors/Partners**: Not publicly available
- **Growth Signals**: The company is actively hiring across engineering, project management, and IT roles. Job postings have appeared regularly in recent months. LinkedIn followers have grown at +3.4% monthly, indicating growing interest.

## Competitive Advantages
- **Stealth Mode as a Moat**: By operating in stealth, the company can protect proprietary technology, manufacturing processes, and material science breakthroughs from competitors during critical R&D stages.
- **Advanced Manufacturing Focus**: Emphasis on "advanced manufacturing techniques" and "next-generation energy storage architectures" suggests a manufacturing-centric approach that is harder to replicate than purely chemical innovations.
- **Talent Pipeline from Tesla**: LinkedIn data shows talent sources include Tesla, indicating potential knowledge transfer from the leading EV battery manufacturer.

## Strategic Focus
- **Building the Engineering & Operations Team**: Current hiring priorities focus heavily on engineering, program management, and operations — roles critical to scaling from R&D to pilot production.
- **Manufacturing Readiness**: Job descriptions emphasize procurement, vendor coordination, logistics, and equipment delivery — suggesting the company is moving toward prototype or pilot manufacturing scale.
- **San Jose Operations**: Listing roles in San Jose points to establishing physical lab and manufacturing facilities in a key clean-tech hub.

## Why Work Here
- **Mission-Driven**: Direct impact on clean energy transition and climate change through battery innovation.
- **Early-Stage Equity Potential**: As a stealth startup, early employees likely receive significant equity upside.
- **Compensation**: Competitive base salaries — for example, the Engineering Project Specialist role lists a base salary range of $145,000–$190,000.
- **Hands-On Ownership**: Job descriptions emphasize real ownership and cross-functional collaboration — not just supporting roles.
- **Growth Opportunity**: Roles are designed to scale with the company, offering clear career progression from operations into broader procurement, vendor management, and supply chain leadership.
- **On-Site Culture**: All roles are on-site (San Jose/San Francisco Bay Area), suggesting a collaborative, lab-intensive environment typical of hardware startups.
- **Tech Stack Exposure**: Current tech stack includes tools like Rippling, Python, Jira, SolidWorks, CATIA, Altium, ANSYS, and Linux — indicating a sophisticated engineering environment.
- **Equal Opportunity Employer**: Company explicitly states equal opportunity employment practices.

## Sources
1. [batterystartup.careers](https://www.batterystartup.careers/)
2. [LinkedIn - Stealth Battery Startup](https://www.linkedin.com/company/stealth-battery-startup)
3. [Rise Open Jobs - Engineering Project Specialist](https://joinrise.co/stealth-mode-battery-startup/engineering-project-specialist-eps-t4hp)
4. [Jobsearcher - Stealth Battery Startup](https://jobsearcher.com/companies/stealth-battery-startup)
5. [Ashby - Stealth-mode Battery Startup Careers](https://jobs.ashbyhq.com/company)

## Other roles at Stealth-mode Battery Startup

- [OT Engineer](https://feeny.ai/job/ot-engineer-stealth-mode-battery-startup-san-jose-283exp9y5m0n) — San Jose, CA
- [Capital Projects Program Manager](https://feeny.ai/job/capital-projects-program-manager-stealth-mode-battery-startup-san-jose-4p3j6wvqxbzp) — San Jose, CA
- [Global Supply Manager](https://feeny.ai/job/global-supply-manager-stealth-mode-battery-startup-san-jose-snwe21g2fbjr) — San Jose, CA
- [Quality Control Technician](https://feeny.ai/job/quality-control-technician-stealth-mode-battery-startup-san-jose-23bxe0knfah6) — San Jose, CA
- [Engineering Technician - Battery Test](https://feeny.ai/job/engineering-technician-battery-test-stealth-mode-battery-startup-san-jose-9ttrfnd5rrh9) — San Jose, CA
- [Facilities Engineering Specialist](https://feeny.ai/job/facilities-engineering-specialist-stealth-mode-battery-startup-fremont-5j7eq94fh4t5) — Fremont, CA
- [Engineering Technician, Cell](https://feeny.ai/job/engineering-technician-cell-stealth-mode-battery-startup-san-jose-t9swyaxwsrg5) — San Jose, CA
- [Equipment Engineer, Manufacturing](https://feeny.ai/job/equipment-engineer-manufacturing-stealth-mode-battery-startup-san-jose-68dyfjf7bwym) — San Jose, CA
- [Equipment Technician, Manufacturing](https://feeny.ai/job/equipment-technician-manufacturing-stealth-mode-battery-startup-san-jose-91e6s81ft4hd) — San Jose, CA
- [Manufacturing Operations Manager](https://feeny.ai/job/manufacturing-operations-manager-stealth-mode-battery-startup-san-jose-4kd1mpk9z6tg) — San Jose, CA