The battery in an electric vehicle affects not only range, but also safety, weight, service life and total operating costs. It is therefore not merely an energy storage device, but one of the vehicle’s most important systems.
For OEMs, Tier 1 suppliers and R&D teams, the key question is not only “What is the battery capacity?” but also “How will the entire battery system perform under real operating conditions?” What should be considered to ensure that the battery design supports both the vehicle’s technical performance and the profitability of the entire programme?
Battery capacity expressed in kWh affects the potential range of an electric vehicle, but it is not sufficient on its own to assess the efficiency of the entire system. In eMobility projects, batteries are often evaluated primarily in terms of energy capacity because range remains one of the vehicle’s most important commercial parameters.
Real-world range is also affected by battery pack weight, power electronics efficiency, the energy management strategy, rolling resistance, aerodynamics, route profile, ambient temperature and the way the vehicle is used. The same battery pack may deliver different results in a city bus, commercial vehicle, off-highway machine, train or passenger car. Each of these segments has a different duty cycle, load profile, charging windows and availability requirements.
The battery affects the vehicle architecture through its location, geometry and weight. These parameters influence the load-bearing structure, crash safety, passenger or cargo space, ground clearance, centre of gravity and service access. As a result, decisions concerning the battery system quickly translate into production costs, homologation, logistics, maintenance and the potential for future vehicle upgrades.
An electric vehicle battery system is not a single component, but an integrated system. It includes cells, modules, the enclosure, electrical connections, cooling or heating systems, protection devices, sensors, controllers, wiring harnesses, high-voltage connectors, communications and software. Each of these layers affects the others.
Battery design requires multiple teams to work in parallel because mechanical, electrical, thermal and software-related decisions are closely interconnected. The mechanical design must account for electrical and thermal requirements. The high-voltage architecture should support functional and service safety. The BMS must receive reliable sensor data while communicating with other vehicle systems. The battery enclosure must protect against environmental exposure, mechanical damage and the consequences of road incidents without adding unnecessary weight.
Battery design should therefore be treated as an interdisciplinary task. It requires the integration of mechanics, electronics, software, simulation, prototyping, testing and validation. The interfaces between these disciplines are where the greatest risks arise, but also where the greatest opportunities exist to optimise vehicle performance and operating costs.
Temperature directly affects battery efficiency, lifespan and safety. Cells operating outside their optimal temperature range lose efficiency, degrade faster and may require charging or discharging power to be limited. Low temperatures reduce the available energy and extend charging time, while high temperatures accelerate ageing and increase the risk of hazardous events.
The thermal management system should be designed around the vehicle’s actual duty cycle. A bus charged several times a day has different requirements from a delivery vehicle covering long distances or an off-highway machine operating in dusty conditions, under vibration and at high loads. The choice of liquid or air cooling, cooling plates, thermally conductive materials and pre-conditioning strategies should be based on an analysis of real use cases, rather than solely on the cells’ nominal parameters.
A BMS (battery management system) monitors voltage, temperature, current, state of charge, state of health and differences between individual cells. Although users do not normally see it, key operating parameters depend on how it performs. Based on the data collected, the BMS manages power limits, charging, cell balancing, diagnostics and emergency responses. BMS data can also support predictive maintenance, charging strategy optimisation, software updates and more effective fleet availability planning.
Electric vehicle battery design should begin with the definition of system requirements, including the vehicle application, duty cycle, range targets, weight and cost assumptions, as well as safety, manufacturing and service requirements. Decisions concerning cell chemistry, module architecture, system voltage, cooling method, enclosure and control strategy should be made only after these requirements have been established.
Battery system development requires an iterative approach. CAE simulations help assess structural strength, thermal behaviour, the impact of weight and potential risk areas. Prototypes make it possible to verify assembly, sealing, vibration resistance, serviceability and integration with the vehicle. Environmental and functional tests show how the battery performs outside nominal conditions.
Validation should not be treated solely as the final confirmation of a completed design. It is a tool for reducing technical and business risk. The earlier a team identifies an issue involving cooling, mounting, communications, the charging strategy or service access, the lower the cost of implementing a change. In the later stages of a programme, even a seemingly minor modification may affect the vehicle structure, wiring harnesses, homologation or the manufacturing process.
An engineering partner can reduce the risks associated with implementing a battery system by combining technical, cost and operational perspectives. This is why OEMs and Tier 1 suppliers increasingly seek support covering the entire product development process. Endego supports product development for the automotive, bus, rail, off-highway machinery and new mobility sectors—from requirements definition, design, simulation and prototyping to testing, validation and preparation for further implementation. This approach helps reduce the number of late-stage changes, improve the management of dependencies between teams and accelerate the transition from initial assumptions to a proven solution.
Endego, a portfolio company of Abris Capital Partners, has completed the sale of its Siemens and Altair software distribution business to Volupe Group. The transaction allows Endego to sharpen its focus on engineering and digitalization services for customers in the mobility and industrial sectors.
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