For any electrified system, from road vehicles to off-highway equipment, range and runtime are often the ultimate measures of success. While increasing battery capacity may seem like the obvious solution, it comes with disadvantages: added weight, higher costs, and integration challenges.
The smarter route lies not in adding more cells, but in maximising the usable energy of the existing pack via smart thermal management.
The temperature–range relationship
Lithium-ion batteries operate efficiently only within a narrow temperature band (typically 20°C–40°C). Deviations in either direction compromise both immediate performance and long-term health:
- High temperatures (>40°C) lead to accelerated degradation, electrolyte breakdown, and safety risks.
- Low temperatures (<10°C) reduce conductivity, increase impedance, lead to power loss, and the risk of lithium plating during charging.
- Temperature gradients (>5°C delta between cells) cause uneven ageing and capacity loss, reducing the effective range of the pack.
In real-world use, uncontrolled temperature excursions force the system to limit power or shut down, robbing end-users of the range or operational reliability they expect.
Heat is the hidden range killer
Thermal stress is most prominent under heavy-duty conditions:
- Fast charging (1.5C and above, meaning charging at a current 1.5 times the battery’s rated capacity, e.g. 150 A for a 100 Ah cell) can drive cell temperatures up by more than 2 °C per minute.
(Note: “Ah” or ampere-hours describes how much charge a battery can store, while “A” or amperes refers to the rate of current flow during charging or discharging.)
- High loads such as acceleration, towing, or steep gradients push pack heat beyond safe thresholds.
- Harsh climates (sub-zero or desert environments) amplify both ends of the challenge.
Without robust thermal management, the system is forced into protective derating modes or suffers accelerated ageing — both leading to significant reductions in range and cycle life.
Cooling strategies: Air vs Liquid
Thermal management systems (TMS) are the linchpin of effective range optimisation. The choice of cooling method plays a critical role:
| Parameter | Air Cooling | Liquid Cooling |
| Heat transfer efficiency | Low | High |
| Temperature uniformity | Poor | Excellent |
| System complexity | Low | High |
| Maintenance | Low | Moderate |
| Energy consumption | Very low (passive) | Medium (active) |
For low-cost or low-power applications, forced-air systems may suffice. But for high-density packs where range and fast charging are priorities, liquid cooling (often glycol-water loops or cold plates) is increasingly the default, offering superior uniformity and tighter thermal control.
Smarter tools for maximising range
Today, advanced TMS solutions extend beyond simple cooling and heating. Key enablers include:
- Preconditioning algorithms – warming cells before charging in cold climates prevents range loss and irreversible plating damage.
- Predictive thermal control – model-based systems anticipate thermal loads (e.g., before fast charging or steep climbs) to optimise coolant flow and minimise wasted energy.
- System integration – reclaiming waste heat from other systems to provide cab heating or battery usage, reducing electrical loads.
- Phase change materials (PCMs) – absorb peak loads during transient spikes, buffering cells against localised heating.
- Immersion cooling – emerging solutions using dielectric fluids deliver near-uniform temperatures, even under ultra-fast charge conditions.
Each of these approaches reduces parasitic losses, improves usable capacity, and ultimately extends range.
Cold climate: the silent range reducer
In sub-zero environments, batteries suffer reduced ionic conductivity and energy output. Cold packs can see range losses of up to 40% if left unconditioned. Smart thermal management mitigates this by:
- Using waste heat recovery from motors and electronics.
- Employing thermal insulation for retention during idle periods.
- Applying active heating loops to bring cells into the optimal zone before use.
Effective preconditioning ensures maximum capacity is available from the very first mile.
Range as a system-level problem
Thermal management must be considered holistically, not just at the battery level. Motors, power electronics, and even cabin comfort systems contribute to the overall thermal picture. Integrated architectures with centralised controllers and multi-valve coolant loops allow dynamic routing of thermal energy, reducing waste and ensuring every subsystem contributes to the goal of extending range.
Go further with smarter thermal management
Maximising range is less about the size of your battery and more about how effectively you control its temperature.
By investing in advanced thermal management strategies, from liquid-cooled packs to predictive algorithms and integrated loops, engineers can unlock longer runtimes, faster charging, and improved reliability without adding unnecessary mass or cost.
At Calatherm, we view thermal management not as an auxiliary function, but as a core enabler of range, safety, and lifecycle performance. Our portfolio, spanning Battery Thermal Management Systems (BTMS), cooling packs, HVAC modules, and control strategies, empowers OEMs to push beyond conventional limits and deliver applications that go further, last longer, and perform more efficiently.