Immersion cooling battery: a review

Immersion cooling for battery systems represents one of the key emerging cooling technologies in recent years. 

As the importance of thermal management of batteries in EVs is more and more understood, a number of innovative strategies are being experimented with. The goal: to enhance battery reliability and efficiency and, consequently, the reliability and efficiency of electric vehicles, which are expected to grow annually at a rate of 36% in the coming decade, according to IEA figures.

The lithium ion battery cooling system and strategies stand at the center of this market’s advancement. Optimizing battery performance has a direct impact on vehicle range, longevity, and safety, as batteries operate optimally within specific temperature ranges. At the same time, overheating batteries pose important safety risks, with potential thermal runaways or even fires. These issues do nothing but confirm the importance of opting for the right cooling system.

Immersion cooling for battery technologies stands out for its heat dissipation capacities, as well as several advantages when compared to liquid cooling systems for batteries. 

These benefits have positioned immersion cooling solutions as a winning strategy for battery cooling. In fact, the global immersion cooling market size is expected to grow at a CAGR of 22.6% from 2023 to 2030, building on this approach’s benefits not only for batteries but also for data center cooling.

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What is immersion cooling battery technology

Immersion cooling battery technology is the process of submerging battery cells in a dielectric fluid in order to dissipate heat generated during operation. 

This method departs from other cooling strategies such as air-cooling methods (where air is circulated around the battery pack); or liquid cooling system for battery (where a liquid is circulated through channels or pipes within or around battery cells). In contrast, immersion cooling provides more efficient heat dissipation by directly immersing batteries in a thermally conductive fluid.

This dielectric fluid (which may include substances such as hydrofluoroethers, silicon oils or water/glycol), presents excellent thermal conductivity properties so that, as batteries generate heat, it can efficiently absorb heat away. The result is a stable and uniform temperature regulation technology.

Types of immersion cooling for battery systems

1. One-phase immersion cooling

Battery cells or modules are submerged in a single-phase dielectric fluid, meaning the fluid remains in a single phase (liquid state) throughout the cooling process.

Heat is then transferred from the battery cells to the surrounding cooling fluid through conduction and natural convection, and then dissipated into the surrounding environment.

The operation takes place at relatively low pressures and temperatures, with the cooling fluid remaining in its liquid form. This simplifies system designs and maintenance.

2. Two-phase immersion cooling

In two-phase immersion cooling, the battery cells or modules are submerged in a dielectric fluid that undergoes a phase change from liquid to vapor and back to liquid. As such, the dielectric fluid absorbs heat from battery cells, boiling and forming vapor bubbles, which carry heat away. At the surface, they condense back into liquid form, then flowing back to the battery cells.

This process enhances heat transfer efficiency compared to one-phase immersion cooling, although it requires a more complex design and operation.

Benefits of immersion cooling for battery technologies

Battery cooling options today include air cooling and the well-known  lithium ion battery cooling system. Compared to these alternatives, immersion cooling for batteries presents the following advantages:

Efficiency in heat dissipation

The main advantage of immersive cooling lies at its capacity to provide direct contact between the cooling medium and the components. In fact, this direct contact has shown to increase the rate of heat transfer by 10,000 times when compared to passive air cooling systems (Roe et al., 2022).

By eliminating the thermal resistance associated with air gaps or interfaces between the component and the cooling medium, immersive cooling minimizes thermal resistance, allowing heat to dissipate more efficiently. 

Uniform temperature distribution

Because immersion cooling completely surrounds the components with the cooling fluid, it facilitates homogeneous temperature distribution across all components. This translates into preventing potential issues such as hotspots, working to ensure consistent performance.

Increased cooling capacity

Immersive cooling systems not only are more efficient, but also are able to dissipate larger amounts of heat without the need for bulky heat sinks or fans. 

Space Optimization and simplified design

When compared to other cooling systems such as lithium ion battery cooling systems, immersive cooling eliminates the need for bulky and heavy equipment and parts. 

Improved reliability and safety

By maintaining components at lower operating temperatures, immersive cooling can help improve the reliability and lifespan of electronic systems. Cooler operating temperatures reduce risks such as fires or thermal runways, but that’s not all: some immersion fluids are active fire suppressants and/or flame-retardants.

All in all, immersive cooling stands out as an efficient solution for battery thermal management. As a technology that will continue to evolve in the coming years, it’s set to play an increasingly important role in battery cooling and the developing EVs industry.

Current challenges for the advancement of immersion cooling technologies include the cost of cooling fluids, and the systems’ perceived complexity when compared to conventional solutions such as air-cooling. 

immersion cooling battery

All things considered, immersion cooling for batteries will likely stand out in the coming years, with the potential to enhance heat transfer to unprecedented rates. However, important advancements must be made in understanding issues such as which working fluid is the most convenient, as well as comparing single phase and 2-phase systems when facing project specificities.

The choice of the right thermal management system for batteries is in fact expected to remain a crucial one in the future of EVs development. As such, it requires expert accompaniment that moves away from ‘one-size-fits-all” solutions. Briefly put, successful battery cooling systems must incorporate notions such as: 

  • Efficiency in heat transfer
  • The intended battery application
  • Batteries’ desired performance within the project, including changing rates
  • Space availability and compact design
  • Cost-effectiveness 
  • Safety and risk assessment
  • Reliability and durability
  • Compatibility with different battery components
  • Potential maintenance needs
  • Sustainability

As thermal engineering experts, at ARANER we are at the forefront of devising the cooling systems that will shape the future of battery thermal management. With efficiency and sustainability guiding our cooling solutions, we’ve developed a number of state-of-the-art cooling solutions across the globe, including our innovative district cooling line.

Personalization and tailor-made solutions are at the heart of our operations, as we strive to provide the best solution to each project’s needs. Guided by our expert thermal engineers and our decades-long experience in the cooling sector, our cutting-edge solutions involve the most advanced thermal management for batteries, including immersion cooling technologies. 

Want to learn more about immersion cooling and how to implement the best technology for your project? At ARANER, we work to become the key allies needed for the development of battery production systems, advancing the industry’s efficiency and reliability.  Get in touch with us and speak to our team about how we can help you achieve it.

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