Job Description

About us

Rimac Energy is the energy storage division of Rimac Group, the Croatian technology company behind the world's fastest electric hypercar and industry-leading EV powertrain technology. Rimac Energy applies that same performance engineering to grid-scale battery storage, developing the SineStack Battery Energy Storage System (BESS) alongside an in-house Battery Management System and Battery Intelligence software platform. Headquartered in Zagreb with a manufacturing and innovation site in Witney, UK, the team is scaling fast as it moves from pilot deployments into full-scale European manufacturing.

The Role

We're looking for a Battery Intelligence Engineer to own how we understand our cells, from selecting and testing them, to analysing how they perform and age in the field. You'll be a hands-on engineer, just as comfortable with the physical testing of cells as you are when delving into the data.

The role requires knowledge of the technical performance aspects of lithium-ion batteries, from understanding the requirements around selecting appropriate cells for a product, to knowing how to validate our advanced SoC and SoH algorithms on a real system.

Key Responsibilities

Cell Testing & Selection

• Engage with cell suppliers on their latest offerings and future cell roadmaps, shortlisting candidate cells for testing.
• Plan and run cell testing, covering all different aspects of performance from electrical, mechanical, thermal, ageing, and safety.
• Recommendations of which cell to select for each product, backed by the test data and the needs of the project.

Data Analysis

• Analysis of cell test data and the generation of test reports to highlight a cell’s performance characteristics.
• Tracking selected cells through module and rack build, reviewing the build and test data at each stage to ensure consistent and predictable performance.
• Follow the cell's operation in the field, using fleet data to spot trends in performance, safety and ageing.

Algorithm Validation

• Create test plans to validate our algorithms and models, across embedded, edge, and cloud.
• Design test rigs to validate our cells and modules in unique ways to mimic the real-world environment and not just a static lab.
• Lead data generation and analysis, comparing results against model outputs and flagging where they diverge.
• Support degradation assessments and lifetime optimisation.

Technical Expertise

• Act as a technical expert on current and future lithium-ion battery technology.
• Consult with stakeholders on the impact of the BESS design on the performance of the cell.

What We're Looking For

• Engineering or STEM degree (Bachelor's or Master's), or equivalent experience.
• Strong knowledge of lithium-ion cell behaviour, including performance, safety and ageing.
• Hands-on battery testing experience, including test equipment and data acquisition.
• Experience designing and building test rigs.
• Python and/or MATLAB for analysing test and field data.
• Understanding of how SoC and SoH estimation works and how to validate it on real products.
• Clear communication and a collaborative, cross-functional working style.

Nice to have

• Experience working directly with cell suppliers on cell selection.
• Exposure to module or rack build and integration.
• Knowledge of battery safety standards and regulations.
• Python data engineering experience.
• PhD or research-level background in electrochemistry or battery physics.

What Rimac Energy Offers

• The chance to shape the battery intelligence behind SineStack as it scales into full European manufacturing.
• A fast-paced, engineering-driven culture where practical problem-solving and initiative are genuinely valued.
• An educational budget and continuous development, with exposure to rapidly evolving energy and power electronics technology.
• 26 days' annual leave plus 8 public holidays.
• 10 days' fully paid sick leave and 5 days' paid marriage leave.
• 4 months' paid maternity leave and 2 weeks' paternity leave.
• Company pension scheme with auto-enrolment.
• AXA and Medicash private medical insurance for you and your immediate family.
• Service awards, a remote working day by agreement, and a pet-friendly office with relaxation zones and daily fresh fruit.

How to Apply

Submit a CV and a brief cover note outlining relevant battery testing, model validation or analytics experience.

Rimac Energy is an equal opportunity employer and welcomes applications from all qualified candidates.