<h3>About Mainspring</h3><p>Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more.</p><p>The <a href="https://www.mainspringenergy.com/company"><span style="color:#3598db;"><span style="text-decoration:underline;">core values</span></span></a> that ground our work, guide our decisions, and connect us together:</p><ul><li>Pragmatic Optimism</li><li>Excellence without Ego</li><li>Proactive Collaboration</li></ul><div><br></div><h2>About the Role</h2><p>Mainspring Energy is seeking a Staff Mechanical Engineer – Battery Design to lead battery pack and module development for current and future energy platforms.</p><p>As Mainspring's internal battery technical authority, you will help define next-generation battery architectures for future products while improving systems already in production. You'll partner closely with battery suppliers to influence pack and module designs and drive solutions that balance safety, reliability, manufacturability, performance, and cost. You'll influence key decisions across cell integration, thermal management, safety, and system architecture while working at the intersection of mechanical, electrical, and battery engineering.</p><p>Our battery systems do far more than just store energy. They are the dynamic core of our linear generator platform. Tightly integrated into every sub-system, they act as the ultimate performance driver—sparking to life during grid-islanded startups, taming dynamic transient loads, and delivering resilient long-duration standby. This role is your chance to tackle complex battery engineering challenges head-on, drive our supplier strategy, and ensure our systems deliver rock-solid, scalable reliability in the real world. </p><p>The ideal candidate combines deep lithium-ion battery pack expertise with strong supplier-management experience and the ability to translate system requirements into robust production-ready designs.</p><br><br><h3>Key Responsibilities</h3><ul><div><li>Serve as Mainspring’s technical lead for battery pack and module design.</li><li>Partner with battery suppliers to review, improve, and influence pack and module architectures.</li><li>Own battery hardware from requirements definition through production launch and sustaining engineering.</li><li>Evaluate battery designs for safety, reliability, manufacturability, thermal performance, lifecycle, and cost.</li><li>Lead technical reviews of cell integration, interconnect systems, thermal solutions, and safety features.</li><li>Support supplier selection, design reviews, validation activities, and manufacturing readiness.</li><li>Develop battery architectures for future generator platforms.</li><li>Collaborate with Electrical Engineering, BMS, Reliability, Manufacturing, Test, NPI, and Supply Chain teams.</li><li>Lead root-cause investigations and corrective actions for production, test, and field issues.</li><li>Provide technical leadership on complex battery-related challenges.</li><li>Travel to supplier sites as needed to support development and issue resolution.</li></div></ul><h3>Qualifications</h3><ul><div><li>BS or MS in Mechanical Engineering or a related discipline.</li><li>10+ years of engineering experience with significant focus on lithium-ion battery pack or module design.</li><li>Deep understanding of battery pack and module architecture.</li><li>Experience working directly with battery suppliers and contract manufacturers.</li><li>Strong knowledge of cell integration and interconnect design, including bus bars, current collectors, voltage sensing, harnessing, and cell terminal joining methods.</li><li>Experience designing series and parallel battery architectures.</li><li>Working knowledge of cell construction, dielectrics, fusing, compression systems, and thermal interface materials.</li><li>Experience with battery thermal management and thermal runaway propagation mitigation.</li><li>Understanding of battery aging, lifecycle performance, and charge/discharge behavior.</li><li>Knowledge of environmental durability, vibration, grounding, creepage/clearance, and EMI-related packaging requirements.</li><li>Experience supporting validation testing, manufacturing launch, and sustaining engineering.</li><li>Experience with UL certification of battery systems.</li><li>Proficiency with SolidWorks and PLM systems.</li></div></ul><h3>Preferred Qualifications</h3><ul><div><li>Experience with prismatic-cell battery systems.</li><li>Knowledge of BMS integration, contactors, relays, and protection systems.</li><li>Experience with high-voltage battery or power systems.</li><li>Experience with battery thermal protection materials and thermal interface design.</li><li>Familiarity with FEA tools such as Ansys.</li><li>Experience with products deployed in harsh outdoor environments.</li><li>Background in EVs, energy storage systems, industrial electrification, power electronics, or other ruggedized energy platforms.</li></div></ul><br><p>Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.</p><p>In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.</p><p>This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.</p>

<p class="text-steel f-b1 md-max:mb-d">At Mainspring we believe the fastest path to the net-zero carbon grid is vastly increasing the amount of solar and wind power while building a supporting clean energy system that ensures affordability and multi-day, cross-season resilience. Getting there requires flexible, scalable, local technologies that can adapt to the shifting grid landscape &ndash; including the transition from natural gas to renewable fuels like biogas, green ammonia, and green hydrogen.</p>
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<p class="text-steel f-b1">The Mainspring Linear Generator delivers an unmatched level of flexibility for the transition ahead. It&rsquo;s local so you can site where power is needed, it&rsquo;s dispatchable so you can ramp up and down to complement renewables, and it&rsquo;s fuel-flexible so you can operate on the cleanest fuels available today and in the future. Our products are already at work at Fortune 500 customer sites, accelerating the arrival of the net-zero carbon grid.</p>
</div>

Staff Mechanical Engineer - Battery Design

<h3>About Mainspring</h3><p>Mainspring Energy manufactures and delivers fuel-flexible, low-emissions local power solutions that rapidly add new capacity and deliver reliable, affordable, and sustainable electric power. The company began commercial shipments of its Mainspring Linear Generators in 2020 and today has hundreds of megawatts in advanced development and field operations for leading Fortune 500 companies, data centers, and utilities. Mainspring also partners with global energy leaders including AEP, NextEra Energy Resources, Schneider Electric, and more.</p><p>The <a href="https://www.mainspringenergy.com/company"><span><span>core values</span></span></a> that ground our work, guide our decisions, and connect us together:</p><ul><li>Pragmatic Optimism</li><li>Excellence without Ego</li><li>Proactive Collaboration</li></ul><div><br /></div><h2>About the Role</h2><p>Mainspring Energy is seeking a Staff Mechanical Engineer – Battery Design to lead battery pack and module development for current and future energy platforms.</p><p>As Mainspring's internal battery technical authority, you will help define next-generation battery architectures for future products while improving systems already in production. You'll partner closely with battery suppliers to influence pack and module designs and drive solutions that balance safety, reliability, manufacturability, performance, and cost. You'll influence key decisions across cell integration, thermal management, safety, and system architecture while working at the intersection of mechanical, electrical, and battery engineering.</p><p>Our battery systems do far more than just store energy. They are the dynamic core of our linear generator platform. Tightly integrated into every sub-system, they act as the ultimate performance driver—sparking to life during grid-islanded startups, taming dynamic transient loads, and delivering resilient long-duration standby. This role is your chance to tackle complex battery engineering challenges head-on, drive our supplier strategy, and ensure our systems deliver rock-solid, scalable reliability in the real world. </p><p>The ideal candidate combines deep lithium-ion battery pack expertise with strong supplier-management experience and the ability to translate system requirements into robust production-ready designs.</p><br /><br /><h3>Key Responsibilities</h3><ul><div><li>Serve as Mainspring’s technical lead for battery pack and module design.</li><li>Partner with battery suppliers to review, improve, and influence pack and module architectures.</li><li>Own battery hardware from requirements definition through production launch and sustaining engineering.</li><li>Evaluate battery designs for safety, reliability, manufacturability, thermal performance, lifecycle, and cost.</li><li>Lead technical reviews of cell integration, interconnect systems, thermal solutions, and safety features.</li><li>Support supplier selection, design reviews, validation activities, and manufacturing readiness.</li><li>Develop battery architectures for future generator platforms.</li><li>Collaborate with Electrical Engineering, BMS, Reliability, Manufacturing, Test, NPI, and Supply Chain teams.</li><li>Lead root-cause investigations and corrective actions for production, test, and field issues.</li><li>Provide technical leadership on complex battery-related challenges.</li><li>Travel to supplier sites as needed to support development and issue resolution.</li></div></ul><h3>Qualifications</h3><ul><div><li>BS or MS in Mechanical Engineering or a related discipline.</li><li>10+ years of engineering experience with significant focus on lithium-ion battery pack or module design.</li><li>Deep understanding of battery pack and module architecture.</li><li>Experience working directly with battery suppliers and contract manufacturers.</li><li>Strong knowledge of cell integration and interconnect design, including bus bars, current collectors, voltage sensing, harnessing, and cell terminal joining methods.</li><li>Experience designing series and parallel battery architectures.</li><li>Working knowledge of cell construction, dielectrics, fusing, compression systems, and thermal interface materials.</li><li>Experience with battery thermal management and thermal runaway propagation mitigation.</li><li>Understanding of battery aging, lifecycle performance, and charge/discharge behavior.</li><li>Knowledge of environmental durability, vibration, grounding, creepage/clearance, and EMI-related packaging requirements.</li><li>Experience supporting validation testing, manufacturing launch, and sustaining engineering.</li><li>Experience with UL certification of battery systems.</li><li>Proficiency with SolidWorks and PLM systems.</li></div></ul><h3>Preferred Qualifications</h3><ul><div><li>Experience with prismatic-cell battery systems.</li><li>Knowledge of BMS integration, contactors, relays, and protection systems.</li><li>Experience with high-voltage battery or power systems.</li><li>Experience with battery thermal protection materials and thermal interface design.</li><li>Familiarity with FEA tools such as Ansys.</li><li>Experience with products deployed in harsh outdoor environments.</li><li>Background in EVs, energy storage systems, industrial electrification, power electronics, or other ruggedized energy platforms.</li></div></ul><br /><p>Does your experience not meet all of our posted requirements? Studies have shown that some people are less likely to apply to positions unless they meet every listed requirement. At Mainspring, we are committed to building a diverse, inclusive, flexible, and collaborative environment, so if you want to help us transition the world to clean and affordable electricity, and don’t meet all posted requirements for a particular role, we’d still love to hear from you. Mainspring can sometimes be flexible enough to shift responsibilities for the right person, or otherwise identify open or upcoming roles that may better fit your professional background.</p><p>In more traditional words, Mainspring Energy, Inc is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, or protected veteran status and will not be discriminated against on the basis of disability.</p><p>This compensation and benefits information is based on Mainspring Energy's estimate as of the date of publication and may be modified in the future. We generally do not negotiate on salary once we have made an offer. The level of pay within the range will depend on a variety of job-related factors that may include location, relevant prior experience and/or education, or particular skills and expertise. New hires joining the company tend to be paid within the starting base pay range noted above, with opportunities to increase pay over time based on development of additional skills, competencies, and company-specific knowledge.</p>

Staff Mechanical Engineer - Battery Design

About the Job

About the Company

Mainspring Energy

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