Battery System Engineer

Battery Systems Engineer

We're ALSO, an electric mobility company originally conceived as a part of Rivian. We're a passionate team of builders, dreamers, doers and innovators, focused on creating entirely new (not to mention, innovative and delightful) vertically integrated, small EVs designed to meet the global mobility challenges of today and tomorrow. Our mission is to inspire everyone to ride ALSO—replacing many local car, truck and SUV miles with ones on vehicles that are more affordable, more enjoyable and 10-50x more efficient.

We're looking for a Battery Systems Engineer (all levels) to own the battery system architecture and analytical foundation behind our battery systems. You will help define not just the battery pack, but the broader energy strategy and operating philosophy of the vehicle platform.

You will drive the key technical decisions across cell selection, charging strategy, pack architecture, thermal behavior, controls integration, performance, degradation, and operating strategy. Your work will directly shape product direction, vehicle capability, user experience, range, cycle life, cost, and the long-term energy strategy of the platform.

This is a highly cross-functional systems role spanning battery engineering, vehicle architecture, controls, thermal systems, and product definition. You should be equally comfortable building models, defining operating concepts, debating architecture tradeoffs, and helping teams converge on the right technical decisions.

What You Will Do

• Own the analytical foundation behind the battery system. Lead trade studies across chemistry, pack topology, SOC window, cell selection, and operating limits — translating engineering decisions into cost, range, performance, and cycle life tradeoffs that drive product and business direction
• Build and advance cell- and pack-level electrical, thermal, and degradation models. Develop battery duty cycles from real-world usage data and mission profiles, correlate models against measured data, and use them to set architecture decisions, design targets, and operating limits.
• Define how the battery operates — charging strategy, operational use cases, user-facing behavior, degradation management, and end-of-life operating strategy. Ensure these are reflected in system requirements, controls logic, and vehicle integration.
• Own cell evaluation and down-selection. Define characterization test plans, interpret performance and degradation data, and translate cell behavior into pack-level model inputs, design constraints, and BMS operating envelopes.
• Define battery system requirements: protection thresholds, thermal limits, charge/discharge constraints, contactor and fuse sizing, fault detection, and end-of-life criteria. Partner with BMS hardware, firmware, and controls teams to ensure what gets implemented reflects real-world operating realities — you bring the use case context and cell behavior constraints they need to succeed.
• Close the loop between analysis and hardware. Define test cases, support bench and vehicle-level bring-up, and drive model-to-measurement correlation across electrical, thermal, and degradation domains.
• You'll be an early member of a growing battery engineering team. How you work — your rigor, your speed, your standards — sets the bar for the engineers who come after you.

What You Will Bring

• 8+ years in battery systems engineering with demonstrated ownership of battery architecture and requirements on a shipped product — not program support, not analysis in isolation
• Deep understanding of lithium-ion cell behavior: electrochemical operating principles, thermal characteristics, degradation mechanisms, and how these translate into real-world duty cycle and pack design constraints
• Hands-on modeling expertise (Python, MATLAB, Simulink): equivalent circuit models, thermal networks, degradation behavior, pack-level simulation. You have built these from scratch, not just run them
• Experience developing or validating duty cycles for EV or electrified powertrain applications and translating mission profiles into battery requirements and operating limits
• Proven ability to translate cell and pack behavior into BMS…