Getting robotics battery design right

WHEN A robot stops, everything around it tends to stop too. The battery pack isn’t usually the first thing people think about, yet it’s often the part that determines whether the machine performs as it should. When it’s designed around the real duty cycle and tested properly, it works quietly in the background, keeping operations running as planned. When it isn’t, problems appear quickly - shorter run times, heat build-up or premature wear that can halt operations altogether. Consistent performance and reliable operation are the result of design decisions made early, based on how the robot will actually operate day to day.

The first step is to define how the robot will really work in service: how long it runs for, how often it charges and the environment it operates in. A unit working in a clean warehouse faces very different demands to one that spends its days on a loading dock or outdoors. Those early decisions shape everything that follows – from electrical design to how the pack is assembled and validated. Leaving these details open too long is one of the most common causes of redesigns, delivery slips and added cost.

Avoid the freeze

Without clear checkpoints, assumptions multiply and time disappears. To avoid drift and late redesigns, development needs to follow defined stages. The first, Scope Freeze, is where the technical requirements, compliance planning and project timelines are agreed so that everyone is working to the same expectations. The second is working towards Design Freeze, when the detailed design has been reviewed and validated – drawings, test plans and documentation are finalised, so the pack is ready for a prototype build. The final stage is to validate costs, including the bill of materials, 3rd party supplier quotes, tooling, and commercial plan in order to reach Cost Freeze before moving to production. Taking this step-by-step approach keeps teams aligned, prevents scope creep and gives customers confidence that progress is controlled and measurable.

Once the application of the end-product is fully understood, chemistry choice becomes the next key decision. Lithium-iron-phosphate (LFP) cells are stable and long-lasting, making them a reliable option for robots that operate continuously. Nickel-manganese-cobalt (NMC) offers higher energy density where space is limited, which suits compact autonomous mobile robots (AMRs) and drones. Lithium-titanate (LTO) performs well for fleets that need very fast charging or work in colder environments. There’s no universal answer; the right chemistry is the one that balances energy, cost and weight in line with the duty cycle. An experienced battery design and manufacturing partner will help an OEM’s project team to weigh up the pros and cons for different chemistries and will guide the right decision based on each product’s specific requirements.

It’s also worth deciding early how much usable capacity the pack should retain after a shift. Too little and the robot may fail to complete its route; too much adds unnecessary cost and weight. A good rule of thumb is to design for around 80% of original capacity at end-of-life, as this aligns with common industry definitions of usable battery life and keeps performance consistent over time. Having these realistic conversations early prevents costly field issues and builds shared understanding across the project team.

One-off engineering

Developing a custom pack always involves an element of one-off engineering. Drawings, simulations, prototypes, test engineering and certification, together known as non-recurring engineering (NRE), are what turn an idea into a manufacturable product. Planning for this work up front shortens development overall and helps avoid costly redesigns. It also means cost, safety and performance targets can be validated together, rather than discovered late in the project. It’s what turns a one-off prototype into a product that can be built consistently and safely at scale.

Regulation is now an equally important consideration. From 18 February 2027, industrial, EV and light-transport batteries above 2 kWh must carry a digital passport accessible via a QR code. Larger robot packs will fall within scope first, while smaller systems may follow as the rules develop. Building traceability into the design - linking cell batches, process data, firmware versions and serial numbers - means the information needed for the passport already exists, rather than having to be recreated later.

Although it may sound bureaucratic, the benefit goes beyond compliance. A clear data record allows maintenance teams to trace faults quickly, gives customers the evidence they need during audits and simplifies recycling at the end of service life. It also protects OEMs if safety or performance questions arise years down the line, because the details are already documented.

Battery design rarely gets the spotlight, but it’s what underpins reliability. Getting the fundamentals agreed early, planning the engineering work properly and thinking ahead to new regulations makes the difference between a programme that runs smoothly and one that constantly needs attention. Reliability isn’t luck, it’s the result of disciplined design. With that groundwork in place, the battery becomes the most dependable part of the robot - the one nobody has to think about at all.

Will your next robot battery be built that way from the start?

Mark Rutherford is CEO of Alexand Battery Technologies

www.alexandertechnologies.com