Senior Cell Validation & Reliability Engineer

Job Title: Senior Cell Validation & Reliability Engineer

Department: Cell Engineering

Reports To: Cell Applications Engineering Manager

Position Type: Full-time

About the Company

Peak Energy is the first American venture to advance globally proven sodium-ion battery systems as the storage standard for the new era of renewable energy on a resilient grid.

Sodium-ion is cheap, readily available, and safe — making it the leading contender in a rapidly evolving market.

Our leadership team is powered by decades of expertise in scaling gigawatt-level innovation at world‑class companies such as Tesla, Northvolt, Apple, Powin, Enovix, Zipline, Solid Power, Sun Power, and Fluence. We are backed by strategic investment and product partners including TDK Ventures, Eclipse Ventures, and GM Ventures.

We recently announced America's first sodium‑ion grid storage factory in Sacramento with production starting Q1 2027, and over $1B in signed customer commitments including Jupiter Power and Energy Vault.

About the Role – Senior Cell Validation & Reliability Engineer

Peak Energy is seeking a Senior Cell Validation & Reliability Engineer to own the validation and reliability foundation for the cells integrated into our energy storage systems. This role will move beyond cell specification verification to quantify how cell-to-cell and batch-to-batch variation impacts system‑level performance and reliability.

You will design the studies, own the statistical analysis, and deliver cell‑level validation verdicts and reliability inputs that inform Peak Energy's system design and 20‑year calendar life expectations. You will work closely with cell test engineering, cell modeling, ESS engineering, supplier quality, and other cross‑functional teams to translate cell performance and variation into actionable system requirements.

Test execution will be carried out by the cell test engineering team, predictive modeling by the cell modeling function, and system design and system‑level reliability evaluation by ESS engineering. This role owns the cell‑side validation and reliability inputs that connect those functions.

The ideal candidate combines strong battery validation experience with applied reliability statistics and is comfortable turning complex test data into clear engineering decisions.

What You'll Do (Responsibilities)

Cell‑to‑System Integration Validation

• Validate the electrical and mechanical integration of supplier cells into Peak Energy ESS platforms; own the cell‑side validation verdict at each integration point.
• Move validation from spec verification to population statistics: design cell‑to‑cell and batch‑to‑batch variation studies and quantify how variance propagates to system‑level performance — balancing burden, thermal gradients, mechanical preload windows, and energy/power delivery.
• Mechanical: validate cell behavior under system‑representative compression; characterize force versus state of charge and swell over life; deliver force–displacement–life datasets that inform foam/pad selection and preload design by systems engineering.
• Electrical & BMS:
  Assist in analysis with measured variation accounted for of OCV characterization, equivalent‑circuit parameters; quantify cell‑in‑system versus bench performance deltas.
• Establish the statistical foundation: measurement system analysis (MSA / Gauge R&R) across cell test equipment, capability analysis against specification, and statistically justified sample sizes, acceptance criteria, and validation exit criteria.

Cell Reliability Ownership

• Own the cell reliability test roadmap: inform sample size requirements for calendar life, cycle life, and accelerated aging test plans designed explicitly to inform reliability analysis — not only to characterize performance.
• Deliver…