eVTOL aircraft face extreme battery stress during vertical takeoffs, landings, and rapid recharges. These operations produce intense heat, putting lithium-ion batteries at risk of failure or even thermal runaway. Without effective thermal control, battery degradation accelerates, flight range shrinks, and safety becomes questionable — all critical concerns in the aviation field. Liquid cooling has emerged as a game-changing solution, offering superior heat management and paving the way for high-performance, safe, and certifiable eVTOL aircraft.
So how exactly does liquid cooling solve the heat problem in eVTOLs? What technologies are being developed to support this system? In the sections below, we’ll explore the mechanisms, innovations, and integration strategies behind this indispensable thermal solution — and why it’s critical to the success of urban air mobility.
Liquid cooling for eVTOLs involves circulating coolant through engineered channels directly in contact with battery cells. This system dissipates heat efficiently during high-stress phases like takeoff and landing.
Coolant flows through wavy or microchannel designs bonded to cells, extracting heat to a compact heat exchanger. These systems maintain cell temperatures within ±3°C of optimal, avoiding thermal damage.
The most common designs use water-glycol mixtures, channeled through cold plates or serpentine paths that increase surface contact and turbulence, improving thermal exchange. Some eVTOLs, like those from Joby Aviation, employ modular packs with laser-welded plates for even distribution. Compared to air cooling, these systems reduce thermal gradients significantly and require less space for airflow ducts, minimising aerodynamic drag.(source)
Air cooling may work for electric vehicles, but eVTOLs demand more intense and rapid heat removal, especially during vertical flight and fast charging.
Liquid cooling reduces capacity fade to just 0.8% per 100 cycles and supports battery lifespans exceeding 2,000 charge-discharge cycles. It also enables fast-charging times under 10 minutes without risking lithium plating.
At high altitudes or during prolonged hover, air-cooled systems struggle with thermal inertia. Liquid systems, on the other hand, respond quickly to temperature spikes. They also provide better insulation against external temperature swings, making them more reliable in diverse climates. Joby’s cold plate-integrated modules and Beta Technologies’ dual-mode systems illustrate these advantages clearly.
As battery power and density increase, engineers are developing more advanced architectures to optimise liquid cooling without adding excessive weight or complexity.
Technologies like tab cooling, two-phase cooling, and PCM integration improve thermal performance by up to 40% while reducing system mass by over 30%. These designs target heat at the source and adjust cooling capacity dynamically.
Qdot’s tab cooling system, adapted from nuclear fusion research, cools current collectors directly, resulting in a temperature rise of under 5°C during ultra-fast recharges. Two-phase cooling, like Intergalactic’s Eagle5, uses microtubes and phase-change materials to absorb heat at peak load, reducing pump power. PCMs provide latent heat absorption, buffering sudden spikes. These innovations are crucial for missions with unpredictable thermal loads.
In aviation, every gram matters. Cooling systems must balance thermal efficiency with strict weight and space constraints.
Aluminium alloys, carbon fibre composites, and 3D-printed microchannel plates are revolutionising eVTOL cooling systems, cutting weight by up to 22% without compromising strength or conductivity.
NASA-backed research on laser-sintered cold plates with 200 µm channels has demonstrated superior thermal uniformity and durability. Additive manufacturing allows complex geometries for optimal flow, which traditional machining cannot achieve. These structures also withstand over 10,000 pressure cycles — critical for aviation certification. Companies like AddComposites are already commercialising such components.(source)
Cooling systems must work seamlessly with avionics, battery management, and flight controls — often within very tight spaces.
Structural integration of BTMS components into the aircraft’s airframe reduces space and weight usage while enhancing overall system reliability and safety.
Modern BMS units incorporate real-time thermal monitoring and control of coolant flow. Some designs embed coolant channels into wing spars or battery housing, reducing clutter and improving thermal efficiency. Structural batteries — where cells also act as part of the fuselage — represent a promising future trend. Integration also improves redundancy and safety in emergency scenarios.
Despite their advantages, liquid cooling systems are not without trade-offs, particularly in cost, complexity, and regulation.
Challenges include additional mass (target limit: <20% of battery weight), high component costs, vibration durability, and the lack of established airworthiness certification standards.
Pumps, radiators, and sensors all add to the system’s bill of materials. Additionally, complex integration with other onboard systems introduces failure points that require robust engineering and validation. Regulatory bodies like EASA and FAA are still drafting certification pathways for such systems, slowing down mass adoption. Cold-weather performance also demands preheating features, validated in Arctic trials by Beta Technologies.
The next decade will see major shifts in battery technologies and thermal management strategies, aiming for higher energy densities and safer operation.
Emerging trends include solid-state batteries, AI-optimised cooling layouts, cryogenic hydrogen systems, and sustainable materials—all aiming to meet the 500 Wh/kg threshold.
Solid-state batteries eliminate flammable liquid electrolytes, reducing cooling needs while boosting energy storage. AI algorithms such as NSGA-II are already used to optimise coolant channel routing and flow rates in simulation. GKN Aerospace’s cryogenic systems and Boeing’s carbon fibre recycling initiatives show how cooling systems are evolving toward sustainability. Inter-industry collaboration will be crucial in shaping standards and scalability.
Liquid cooling is no longer optional—it is essential for the safe and reliable operation of eVTOL aircraft. From extending battery life and enabling fast charging to managing thermal spikes during vertical flight, these systems address the most pressing technical barriers in urban air mobility. As material science, manufacturing, and design tools advance, liquid cooling will evolve into a lighter, smarter, and more integrated backbone of next-generation electric flight. For innovators, investors, and regulators alike, understanding and investing in this critical system is a necessary step toward airborne electrification.
KO 
EN 
DE 
ES 