EP-4737323-A1 - WING COOLING SYSTEM FOR FUEL CELL

EP4737323A1EP 4737323 A1EP4737323 A1EP 4737323A1EP-4737323-A1

Abstract

An aircraft, including a wing (240) having an exterior with an exterior surface, a first power supply structure (102A) disposed in the wing (240), an electric motor electrically connected to the first power supply structure (102A), a first heat exchanger (110A) disposed in the wing (200), where the first heat exchanger (110A) is disposed adjacent to, and in thermal contact with, at least a portion of the exterior of the wing (240), where the first heat exchanger (110A) is configured to transfer heat to the exterior surface, and a first coolant pump (104) in fluid communication with the first heat exchanger (110A) and the first power supply structure (102A).

Inventors

TAVCAR, GREGOR
Mocan, Blaz

Assignees

Pipistrel D.O.O.

Dates

Publication Date: 20260506
Application Date: 20241128

Claims (15)

An aircraft, comprising: a wing having an exterior with an exterior surface; a first power supply structure disposed in the wing; an electric motor electrically connected to the first power supply structure; a first heat exchanger disposed in the wing, wherein the first heat exchanger is disposed adjacent to, and in thermal contact with, at least a portion of the exterior of the wing, wherein the first heat exchanger is configured to transfer heat to the exterior surface; and a first coolant pump in fluid communication with the first heat exchanger and the first power supply structure.
The aircraft of Claim 1, wherein the first heat exchanger extends, along an inner surface of the exterior, from an upper side of the wing, around a leading edge of the wing, to a lower side of the wing.
The aircraft of Claim 1 or Claim 2, wherein the first heat exchanger forms a first heat exchanger cavity, and wherein the first power supply structure is at least partially disposed in the first heat exchanger cavity.
The aircraft of any preceding Claim, wherein the wing comprises a support structure extending from at least an interior side of the exterior at a lower side of the wing to an interior side of the exterior at an upper side of the wing; and wherein the first power supply structure and the first heat exchanger are disposed between a leading edge of the wing and the support structure.
The aircraft of Claim 4, further comprising: a second power supply structure disposed in the wing between the support structure and a trailing edge of the wing; a second heat exchanger disposed in the wing, wherein the second heat exchanger is disposed adjacent to, and in thermal contact with, at least a portion of the exterior of the wing, wherein the second heat exchanger is configured to transfer heat to the exterior surface; and a second coolant pump in fluid communication with the second heat exchanger and the second power supply structure.
The aircraft of Claim 5, wherein the first heat exchanger is separate from the second heat exchanger; and/or wherein the second heat exchanger comprises a first portion disposed at an upper side of the wing, and further comprises a second portion that is disposed at a lower side of the wing, and that is separate from the first portion of the second heat exchanger.
The aircraft of any preceding Claim, wherein the first power supply structure is a fuel cell.
A cooling system structure, comprising: a first power supply structure; a first heat exchanger having a first inner portion configured to be disposed adjacent to a first portion of a wing exterior of a wing configured for use in flight of an aircraft, the wing having a wing exterior with an exterior surface, wherein the first inner portion at least partially bounds a first fluid cavity, and wherein the first power supply structure is in fluid communication with the first fluid cavity; and a first coolant pump configured to pump first coolant through the first fluid cavity to the first power supply structure, wherein pumping first coolant through the first fluid cavity causes the first heat exchanger to cool the first coolant.
The cooling system structure of Claim 8, further comprising: a second power supply structure; a second heat exchanger having a second inner portion configured to be disposed adjacent to a second portion of the wing exterior, wherein the second inner portion at least partially bounds a second fluid cavity, and wherein the second power supply structure is in fluid communication with the second fluid cavity; and a second coolant pump configured to pump second coolant through the second fluid cavity to the second power supply structure, wherein pumping second coolant through the second fluid cavity causes the second heat exchanger to cool the second coolant.
The cooling system structure of Claim 9, wherein the first heat exchanger is separate from the second heat exchanger.
The cooling system structure of Claim 9 or Claim 10, wherein the second heat exchanger comprises an upper second inner portion configured to be disposed at an inner surface of an upper side of the wing, and further comprises a lower second inner portion that is configured to be disposed at an inner surface of a lower side of the wing, and that is separate from the first inner portion of the second heat exchanger; and optionally wherein the first power supply structure has a prismatic shape that roughly conforms to, and is spaced apart from, an interior surface of the first inner portion
The cooling system structure of any of Claims 8 to 11, wherein the first heat exchanger has a shape conforming to an inner surface of the wing exterior from an upper side of the wing, around a leading edge of the wing, to a lower side of the wing; and/or wherein the first heat exchanger forms a first heat exchanger cavity, and wherein the first power supply structure is configured to be at least partially disposed in the first heat exchanger cavity.
The cooling system structure of any of Claims 8 to 12, further comprising: input piping connecting the first fluid cavity to a first end of the first power supply structure, wherein the first coolant pump is connected to a second end of the first power supply structure; and output piping connecting the first fluid cavity the first coolant pump.
A method, comprising: providing cooling for an aircraft power system of an aircraft by causing a coolant pump to pump coolant along a coolant flow path; wherein pumping coolant along the coolant flow path comprises: moving, using the coolant pump, the coolant from a power supply structure to a heat exchanger, wherein the heat exchanger is disposed in a wing of the aircraft, and is in thermal contact with an exterior of the wing, moving the coolant through the heat exchanger, wherein moving the coolant through the heat exchanger cools the coolant and transfers heat in the coolant to the exterior surface for removal by airflow over the wing; and moving the coolant, after cooling the coolant, to the power supply structure.
The method of Claim 14, wherein the heat exchanger extends, along an inner surface of the exterior, from an upper side of the wing, around a leading edge of the wing, to a lower side of the wing; and optionally wherein: (i) moving coolant through the heat exchanger comprises moving coolant into the heat exchanger near the leading edge and moving coolant in the heat exchanger toward the trailing edge along both the upper side and lower side first heat exchanger; and/or (ii) the heat exchanger forms a heat exchanger cavity, and wherein the power supply structure is at least partially disposed in the heat exchanger cavity.

Description

TECHNICAL FIELD The present invention relates generally to a system and method for providing a cooling system for a power supply device, and in particular, for an in-wing heat exchanger system for cooling fuel cells in the wing of an aircraft. BACKGROUND Recent aircraft development has focused on providing more efficient power systems to power lightweight drones, passenger aircraft, and the like. Many of these developments have focused on alternative power systems using fuel cell technology, electric drive trains, and the like. Similar to internal combustion engines (ICEs), alternative power systems produce not only useful work but also waste heat. However, the challenges of removing this waste heat from alternative power systems are significantly different and often more complex than those faced by ICEs. For instance, although fuel cell systems typically produce less waste heat per unit of useful work due to their higher efficiency, they require larger cooling systems than ICEs. This is because ICEs expel most of their waste heat as hot exhaust gases. In contrast, fuel cell systems operate at much lower temperatures (typically below 100°C), resulting in exhaust gases that do not exceed this temperature. Consequently, the amount of waste heat expelled by fuel cell systems as hot exhaust gases is minimal. Additionally, since fuel cell systems operate at lower temperatures, all heat transfer occurs at smaller temperature differences from the ambient environment, necessitating larger surface areas for heat exchange. Another example is batteries. While they operate at even higher efficiencies than fuel cells and produce even less waste heat per unit of useful work, they must function at even lower temperatures (typically below 40°C). This results in even smaller or almost negligible temperature differences to the ambient environment, requiring even larger surface areas for heat exchange. Rejecting heat to the ambient through large surface areas may, in some instances, require incorporating large radiators, which may add significant drag to an aircraft. Since minimizing drag is a crucial aspect of aircraft design, reducing the additional drag caused by the cooling requirements of alternative power systems is a topic of great interest. Alternative power systems tend to require support features that more traditional internal combustion engines (ICEs) do not require, or require these support features on a smaller scale. Additionally, the alternative power systems tend to have a lower power-to-weight and lower power-to-volume ratio than ICE powered vehicles with similar performance. Thus, alternative power systems tend to be heavier, and bulkier, than traditional vehicle power systems. However, as development of alternative power systems improves, the weight and range of those systems improves, improving the attractiveness of alternative power systems. In particular, fuel cell and battery-powered electric aircraft become more cost effective when the weight of the power systems is improved while keeping or improving range. Notably, the power required for fuel cell or battery-powered electric aircraft results in high current draws that frequently need active cooling. This active cooling tends to be directed to cooling of both, the sources of electric power such as fuel cells or battery systems and the sinks of electric power, such as electric drive motors. Therefore, improvements to cooling of fuel cell or battery power systems of aircraft reduce the weight of the power systems or reduce the drag of a cooling system, improving the range and efficiency of aircraft powered by fuel cell or battery based electric propulsion systems. Fuel cells or batteries tend to generate heat when used. Fuel cells generate heat as a byproduct of generating electricity from the catalyzation of fuel, while batteries tend to heat up when charged or discharged, with more heat being generated when more current is drawn. Providing sufficient current to electric propulsion motors, and to providing a useful travel range requires the use of a fairly large number of fuel cells or batteries, and running a large number of fuel cells or batteries in an enclosed area, such as a vehicle, requires substantial cooling for the batteries in order for the batteries to operate efficiently and safely. Additionally, cooling the batteries extends the lifetime of the fuel cells or batteries. Thus, cooling fuel cells or batteries during use is a critical feature of electric powered vehicles. SUMMARY An embodiment aircraft includes a wing having an exterior with an exterior surface, a first power supply structure disposed in the wing, an electric motor electrically connected to the first power supply structure, a first heat exchanger disposed in the wing, where the first heat exchanger is disposed adjacent to, and in thermal contact with, at least a portion of the exterior of the wing, where the first heat exchanger is configured to transfer heat to the exterior