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Battery thermal management plays a central role in the performance, safety and service life of electric buses, trucks and other commercial vehicles.
High-voltage battery packs operate under demanding conditions, including long duty cycles, high charging power, variable passenger or cargo loads and significant changes in ambient temperature. To maintain stable performance, battery cells must be kept within a controlled temperature range and protected from excessive heat or cold.
Lithium-ion battery cells generate heat during charging and discharging. If this heat is not managed effectively, it can contribute to faster degradation, reduced usable capacity and lower charging performance.
Extreme temperatures can also create operational and safety risks. Excessive heat may increase the likelihood of cell damage or thermal runaway, while low temperatures can reduce available power and limit charging speed.
A Battery Thermal Management System, or BTMS, regulates battery temperature by cooling or heating the battery pack according to operating conditions.
Battery cooling systems can generally be divided into passive and active solutions.
Passive systems rely on natural heat dissipation through the battery enclosure, heat sinks or phase-change materials. They are relatively simple and require little additional energy, but their cooling capacity and temperature control are limited.
Active systems use components such as fans, pumps, compressors and heat exchangers to manage battery temperature more precisely. These systems are better suited to large commercial-vehicle battery packs operating under high loads or fast-charging conditions.
Several cooling architectures are used in electric vehicles.
Air-cooled systems use forced airflow to remove heat from the battery pack. They are comparatively simple and cost-effective, but their cooling performance and temperature uniformity can be limited, particularly in high ambient temperatures.
Liquid-cooled systems circulate coolant through cooling plates positioned close to the battery modules. Heat is transferred from the cells to the coolant and then removed through a chiller or heat exchanger.
This approach provides stronger heat-transfer performance and more uniform temperature control, making it widely used in electric buses and other high-capacity commercial vehicles.
Immersion cooling places battery cells or modules in direct contact with a dielectric fluid. The method can provide high cooling performance and temperature uniformity, but it also introduces additional cost, sealing requirements and maintenance complexity.
Its use in mass-produced commercial vehicles remains relatively limited.
A typical liquid-cooled battery thermal management system operates through a closed coolant circuit.
When the battery management system detects that the pack temperature has exceeded a defined threshold, a pump circulates coolant through cooling plates located beneath or alongside the battery modules.
The coolant absorbs heat from the cells and carries it to a chiller, where the temperature is reduced. The cooled fluid then returns to the battery pack and the cycle continues.
In cold conditions, a PTC heater or another heating element can warm the coolant before it reaches the battery modules. This allows the same system to support both cooling and heating.
The BTMS usually communicates with the vehicle control unit and battery management system through the CAN network. Cooling or heating output can then be adjusted according to battery temperature, vehicle load and operating conditions.
Cooling plates are heat-transfer components installed in close contact with battery modules.
They are often made from aluminium and contain internal channels through which coolant flows. Their design influences how evenly heat is removed across the battery pack.
For commercial vehicles, temperature uniformity is particularly important. Large differences between battery modules can contribute to uneven ageing, reduced performance and lower pack efficiency.
Cooling-plate design must therefore consider channel geometry, coolant flow, pressure drop, material selection, sealing and integration with the battery enclosure.
A BTMS for commercial vehicles must meet more than thermal-performance targets.
Important engineering considerations include:
Product certification can support the validation process, but OEMs and operators should also assess application-specific testing, vehicle integration and field performance.
TKT offers a modular BTMS range for electric buses, trucks and other commercial vehicles.
The product family includes cooling capacities from 3 kW to 10 kW, with optional PTC heating. The units use CAN 2.0 communication and are designed to interface directly with the vehicle control unit and battery management system.
The platform includes a compressor, water pump, cooling fan, temperature sensors and pressure-protection components. Different capacity variants use a common electrical architecture, allowing the system to be adapted to different vehicle platforms.
The company also reports EMC testing covering radiated emissions, immunity and transient electrical conditions. Vehicle manufacturers should review the detailed test methods, standards and application conditions when evaluating the system for a specific project.
When evaluating a battery thermal management system, operators and vehicle manufacturers should look beyond nominal cooling capacity.
The selected system should match the battery size, charging strategy, route profile, ambient conditions and expected daily duty cycle.
For electric buses, additional considerations include stop-and-go operation, repeated fast charging, high passenger loads, depot conditions and seasonal temperature variation.
A properly integrated BTMS can support more stable battery performance, consistent charging behaviour and longer battery service life. Its effectiveness, however, depends on the complete system design, including the battery pack, cooling plates, controls, sensors and vehicle operating strategy.
