Why are chillers needed for battery cooling?

Battery thermal requirements differ significantly from the water‑cooling solutions used for marine power electronics, where conventional low-temperature (LT) cooling water circuit is typically cold enough and suitable for the intended operating range. Batteries, however, demand even lower and far more accurately controlled coolant temperatures to maintain performance, safety and service life. For this reason, marine battery systems are integrated into the similar closed‑loop liquid‑cooling circuits used for power electronics, with dedicated chillers added to reduce the coolant temperature to the level required by the batteries. The closed-loop system also ensures that flow rate and pressure remain within safe, well‑defined limits.

At the same time, battery technology is developing rapidly. Energy density continues to increase, charge and discharge rates are rising, and heat generation varies more dynamically with operating profiles. As hybrid and fully electric vessels become more common, the size of onboard battery installations is growing significantly. This evolution is not limited to vessels: as shore power solutions expand, ports are deploying large stationary battery energy storage systems to stabilise the grid and enable fast charging. All of this increases demand for reliable, scalable cooling solutions suitable for both maritime and shore‑based applications.

Requirements for an optimal marine battery cooling system

Marine environments impose unique demands on cooling systems. Battery cooling is part of a critical energy system, and its performance directly affects vessel availability and operational safety. The system must be engineered to withstand continuous vibration, dynamic loads and varying ambient conditions. The complete cooling system must meet classification society requirements and provide long service life under challenging conditions.

Because the size and cooling demand of battery systems vary widely between vessels and applications, modularity and scalability are key. A modular design allows cooling capacity to be tailored precisely to the need and expanded later without major system redesigns. This benefits both newbuilds and retrofit projects, where available space and installation options may be limited.

Ease of installation and delivery is equally important for project success. A standardised, productised cooling system with integrated chillers reduces project risk, speeds up installation and shortens commissioning time. A compact design with a small footprint and low installation height simplifies integration into technical spaces where every centimetre matters.

Energy efficiency and accurate temperature control are essential for battery performance and lifetime. The cooling system must deliver stable and precise temperature control with minimal energy consumption. Variable‑speed drives enable cooling power to adapt to real operating loads, improving system efficiency and reducing component wear. At the same time, noise levels remain low, which is an increasingly important requirement, particularly on passenger vessels.

Battery thermal management requires not only the correct temperature but also controlled coolant flow and pressure. Closed‑loop cooling systems used for marine power electronics offer an ideal basis for this, as they are engineered to keep flow and pressure stable under all operating conditions. Battery cooling plates function correctly only within a specific flow range, and excessive pressure can damage modules or connectors. Integrating the batteries into the similar closed‑loop system ensures stable operating conditions, while the chiller lowers the coolant to the precise temperature required by the batteries. This combination ensures safe, uniform and optimal cooling performance and leverages the vessel’s existing, proven cooling infrastructure.

Reliability and redundancy – the true value of modularity

Battery cooling systems must provide exceptional reliability. A modular cooling architecture with multiple independent units offers a significant advantage: if one unit fails, cooling capacity is maintained by the remaining modules, ensuring continued safe battery operation. This inherent redundancy increases overall system availability and reduces the risk of unplanned downtime.

Equally important is the ability to replace or service a chiller or another component quickly and easily without shutting down the entire system. Downtime is costly in marine operations, making easy serviceability and fast replacement essential characteristics of a modern cooling solution.

Applications

Liquid cooling with chillers is widely used in the energy storage systems of hybrid vessels and fully electric ships, including ferries and various workboats. It is also a key element in shore power installations and stationary port‑side battery systems that require continuous cooling availability and precise temperature control at high power levels. These include cruise vessels undergoing hybridisation, offshore support vessels with peak‑shaving systems, and ferry operators transitioning to fully electric propulsion.

Adwatec’s extensive expertise in Marine Liquid Cooling

For more than two decades, Adwatec has specialised in advanced liquid‑cooling solutions for demanding marine and industrial applications. Adwatec systems are widely used to cool propulsion drives, shore power equipment, high‑power converters, battery cooling and other mission‑critical electrical systems, where reliability, precise temperature control and long‑term durability are essential.

Adwatec’s cooling units are built on marine‑proven closed‑loop liquid‑cooling technology designed to maintain stable flow, pressure and temperature under all operating conditions. The same principles that ensure trouble‑free operation of propulsion and power‑conversion systems translate directly to the needs of modern marine battery installations. Adwatec’s modular system architecture supports scalable cooling capacity, easy redundancy, flexible installation and fast serviceability.

As battery systems grow larger and more tightly integrated with vessel energy systems, the demand for dedicated low‑temperature cooling solutions continues to rise. Adwatec is actively developing new capabilities that complement its existing liquid‑cooling product family, providing shipyards, integrators and operators with a seamless and future‑ready platform for battery thermal management.

With a deep understanding of marine electrical systems, proven product reliability and a strong focus on modularity and lifecycle support, Adwatec is well positioned to help customers meet the increasing performance and safety demands of large‑scale battery installations—both at sea and shoreside.

Conclusion

As maritime electrification advances, cooling systems must evolve as well. Battery liquid‑cooling systems with integrated chillers are no longer auxiliary equipment but a fundamental part of the vessel’s and port’s energy infrastructure. Future‑ready solutions must deliver marine‑grade durability, modularity and true redundancy, combined with energy efficiency, precise control and easy installation and maintenance. Cooling systems that meet these demands provide the foundation for safe, efficient and long‑lasting battery operation in modern marine applications.

As battery capacities grow and electrification accelerates, high‑quality thermal management becomes a key contributor to the vessel’s overall operational reliability.