A French battery manufacturer, WATTALPS, has recently announced its development of electric vehicle (EV) batteries utilizing immersion cooling technology. These batteries, boasting specifications ranging from 48-800V and 10-500 kWh or more, are designed for demanding commercial EV applications and incorporate native IP67 and IP69K designs. But what exactly is immersion cooling, and why is it generating so much buzz in the EV world?
Decoding Immersion Cooling Technology
Immersion cooling involves submerging battery cells and other heating elements, like busbars and electrodes, directly in a dielectric fluid. This fluid is electrically isolating, non-flammable, non-toxic, and biodegradable. This method offers significantly better thermal performance—up to 20 times higher—than traditional cold plate technologies.
How It Works
The concept is straightforward: by immersing the battery module in a dielectric fluid, direct contact between the heat source and the cooling medium is achieved. Heat is then uniformly absorbed and transferred to a dissipation system, typically a heat exchanger, maintaining the cells within their optimal temperature range.
Single-Phase vs. Two-Phase Immersion Cooling
There are two primary configurations for immersion cooling systems:
- Single-phase immersion cooling: The fluid remains in liquid form and is circulated in a closed loop.
- Two-phase immersion cooling: The fluid evaporates as it absorbs heat and then condenses, providing even higher thermal performance.
The Benefits of Immersion Cooling for EV Batteries
Immersion cooling offers several advantages for EV batteries, including:
- Improved Thermal Management: It keeps battery cells within a tighter temperature range, optimizing performance and extending battery life.
- Faster Charging: It enables repeated fast charges and high current peaks, even in harsh conditions. Some sources claim full charges in under 10 minutes are possible.
- Enhanced Safety: It prevents the propagation of cell thermal runaway, a major safety concern in EV batteries.
- Increased Battery Lifespan: By minimizing thermal stress, immersion cooling can prolong battery life by up to 20%.
- Higher Power Density: It allows battery cells to be packaged more closely together, improving volumetric power density.
WATTALPS’s Innovative Approach
WATTALPS’s immersion-cooled batteries stand out due to several key features:
- Passive and Active Safety: The batteries incorporate technology that prevents the spread of cell thermal runaway, along with an active safety system managed by the battery management system (BMS).
- Robust Design: They feature a native IP67 and IP69K design, making them resistant to dust, shock, water, and vibrations.
- Harsh Condition Performance: They maintain performance in temperatures ranging from -20°C to +50°C.
- Compact Form Factor: WATTALPS states its rectangular block shape modules have the smallest form factor on the market, enabling compact battery packs with quick integration.
- Customizable Solutions: WATTALPS is an IEC 62619 and ISO 26262 up to ASIL C-certified provider and works with customers to design battery packs to meet their specific needs.
Challenges and Future Outlook
Despite its numerous benefits, immersion cooling faces some challenges:
- Fluid Cost: The cost of dielectric fluids can be a significant factor.
- System Complexity: Implementing immersion cooling systems can add complexity to battery pack design.
- Component Aging: The long-term effects of dielectric fluids on battery components need further investigation.
However, the future of immersion cooling for lithium batteries looks promising. Market forecasts predict significant growth in the use of immersion cooling in energy storage systems, with some estimates suggesting an annual growth rate of over 22% through 2030. As the EV market continues to expand, the demand for more efficient, safer, and longer-lasting batteries will likely drive further adoption of immersion cooling technology.
Immersion Cooling: Not Just for EVs
While currently making waves in the EV sector, immersion cooling isn’t limited to just automotive applications. Its superior thermal management capabilities make it suitable for:
- Energy Storage Systems (ESS): Improving the performance and lifespan of batteries used in grid-scale energy storage.
- Data Centers: Originally developed for cooling high-performance computing systems, immersion cooling is finding increased use in data centers to manage the heat generated by powerful processors.
- Marine Applications: Providing efficient cooling for batteries used in electric boats and other marine vehicles.
- Industrial Applications: Cooling batteries used in heavy-duty equipment, construction machinery, and mining equipment.
Other Advancements in EV Battery Technology
While immersion cooling is a notable advancement, it’s essential to recognize other innovations shaping the future of EV batteries:
- Solid-State Batteries: These batteries use a solid electrolyte instead of the liquid or gel electrolyte found in traditional lithium-ion batteries, offering faster charging, longer lifespans, lighter weight, and improved safety. Toyota is aiming to launch EVs with solid-state batteries as early as 2027.
- Silicon Anodes: Silicon anodes can store significantly more energy than traditional graphite anodes, increasing vehicle range and improving efficiency.
- Lithium-Iron-Phosphate (LFP) Batteries: LFP batteries are gaining popularity due to their safety and cost-effectiveness.
- Sodium-Ion Batteries: Using more abundant materials, sodium-ion batteries are a sustainable alternative to lithium-ion, especially for affordable, short-range EVs. CATL, a major battery manufacturer, has announced mass production of its sodium-ion batteries.
- Aluminum-Ion Batteries: While still in early stages of development, aluminum-ion batteries promise to be cheaper, longer-lasting, and faster-charging than lithium-ion batteries.
Conclusion
WATTALPS’s development of a 500 kWh EV battery with immersive cooling tech represents a significant step forward in battery technology. Immersion cooling offers a compelling solution to the challenges of thermal management in EV batteries, promising improved performance, safety, and longevity. As the EV industry continues to evolve, innovations like immersion cooling will play a crucial role in driving the widespread adoption of electric vehicles.
