US-12617542-B2 - Battery storage system for an aircraft

US12617542B2US 12617542 B2US12617542 B2US 12617542B2US-12617542-B2

Abstract

In accordance with one embodiment of the present invention, an aircraft comprises a battery pack mounted external to the aircraft structure. The batteries are configured to vent directly to the environment during battery thermal runaway. In one embodiment, an aerodynamic fairing provides an aerodynamically efficient surface and weather protection during nominal flight conditions. During battery thermal runaway however, the aerodynamic fairing is configured to expose the battery to the environment.

Inventors

Alan BUEHNE
Benjamin Tigner
Bernard AHYOW

Assignees

Archer Aviation Inc.

Dates

Publication Date: 20260505
Application Date: 20220204
Priority Date: 20210205

Claims (9)

1 . An aircraft comprising a nacelle coupled to a structural airframe, the aircraft comprising; a first propulsion battery module mounted between a body of the nacelle and a non-structural fairing of the nacelle, wherein the first propulsion battery module is mounted outside the body of the nacelle; a first thermal barrier interposed between the body of the nacelle and the first propulsion battery module, wherein the first thermal barrier also laterally envelops the first propulsion battery module; and an opening in the first thermal barrier on a side opposite the body of the nacelle, the opening configured to vent gas away from the body and toward the non-structural fairing during a thermal runaway event of the first propulsion battery.
2 . The aircraft of claim 1 wherein the non-structural fairing comprises a material that melts during the battery thermal event.
3 . The aircraft of claim 1 wherein the first propulsion battery module is integrated with the first thermal barrier.
4 . The aircraft of claim 1 further comprising a second thermal barrier interposed between the body of the nacelle and a second propulsion battery module different from the first propulsion battery module.
5 . The aircraft of claim 1 , further comprising a second propulsion battery module mounted between the body of the nacelle and the non-structural fairing of the nacelle, and a second thermal barrier divider interposed between the first and second propulsion battery modules.
6 . The aircraft of claim 1 , wherein the structural airframe comprises a hollow structure.
7 . The aircraft of claim 6 , additionally comprising at least a second propulsion battery module, wherein the first and second propulsion battery modules are disposed external to the hollow structure.
8 . An aircraft for shielding from a propulsion battery thermal runaway event, the aircraft comprising: an airframe structure; at least first and second propulsion battery modules disposed on an outside of the airframe structure; a first thermal barrier configured between the (a) first and second propulsion battery modules and (b) the outside of the airframe structure; and a second thermal barrier configured between the first and second propulsion battery modules, wherein the second thermal barrier laterally envelops each of the first and second propulsion battery modules, wherein the second thermal barrier is configured to vent gas from at least one of the first and second propulsion battery modules, directly to the outside during the propulsion battery thermal runaway event.
9 . The aircraft of claim 8 , wherein at least a portion of the first propulsion battery module is positioned toward a non-structural fairing during aircraft flight.

Description

PRIORITY CLAIM This application claims priority to PCT application having serial number PCT/US22/15208 (filed Feb. 4, 2022), which claims priority to U.S. provisional application having Ser. No. 63/146,407 (filed Feb. 5, 2021). These and all other extrinsic material discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. FIELD OF THE INVENTION The field of the invention is electric energy storage for aircraft. BACKGROUND Lithium batteries can become unstable and enter battery thermal runaway, a condition that can result in fire or explosion. When multiple battery cells are close together, thermal runaway can propagate from one battery cell to the next, a state known as thermal runaway propagation. The condition can be catastrophic if not designed for properly. Lithium batteries undergoing thermal runaway also emit dangerous high-volume hot gas streams (“outgassing”). Outgassing can contribute to thermal runaway propagation as well as present a hazard for the surroundings, the gas is typically very hot and contaminated with particles. To address the above concerns, conventional vehicle propulsion battery systems use a containment structure with dedicated vent passages and access passages for manufacturing and maintenance. The containment structure is often surrounded by vehicle structural elements or is incorporated into the vehicle structure itself. However, such containment structures, with dedicated venting passages, can be very heavy and space consuming. SUMMARY In accordance with one embodiment of the present invention, an aircraft comprises batteries mounted external to the aircraft structure. The batteries are configured to vent directly to the environment during battery thermal runaway. In one embodiment, an aerodynamic fairing provides streamlined aerodynamics and weather protection. During battery thermal runaway however, the aerodynamic fairing is configured to expose the battery to the environment. In one embodiment, an aircraft energy storage system comprises a thermal barrier interposed between the battery pack and the outside of the airframe. The thermal barrier shields the airframe from the batteries and can direct any fire or combustion away from the aircraft structure. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective partially exploded view of an embodiment of a battery storage system for an aircraft. FIG. 2 is a cross-sectional view of an embodiment of a battery storage system. FIG. 3 is a perspective view of an aircraft having a battery storage system as described herein. FIG. 4 is a vertical cross section of an embodiment of a battery storage system. FIG. 5 is a perspective view of a portion of the battery storage system of FIG. 4. FIG. 6 is a cutaway view of an embodiment of an aircraft battery module comprising battery cells. FIG. 7 is a perspective view of an embodiment of an aircraft battery module. FIG. 8 is a perspective view of a portion of an alternative embodiment of a battery storage system. DETAILED DESCRIPTION In accordance with the embodiment of FIG. 1, the aircraft comprises a battery pack mounted external to the aircraft structure. The batteries are configured to vent directly to the environment during battery thermal runaway. In the embodiment of FIG. 1, an aerodynamic fairing provides an aerodynamically efficient surface and weather protection during nominal flight conditions. During battery thermal runaway however, the aerodynamic fairing is configured to expose the battery to the environment. In the embodiment of FIG. 2, an aircraft energy storage system comprises a thermal barrier that shields the airframe, or components inside of the airframe from the batteries and directs heat and hot gas away from the aircraft airframe. The thermal barrier is interposed between the batteries and the outside of the airframe. The thermal barrier protects the aircraft structure from fire or combustion, while diverting the fire or combustion away from the aircraft structure. By placing the battery outside of a nacelle, the nacelle can be more rigid and lighter. This is a result of fewer interruptions to the airframe structure. For example, a composite nacelle with the battery housed internal to the nacelle structure would need holes through the composite structure for installing and servicing the battery and related systems. By placing the batteries external to the airframe structure, the need for passages through the airframe structure are minimized. The weight of the resulting structure can be significantly minimized for a desired rigidity. In one aspect, the subject matter herein describes a battery storage system configured to use airflow to prevent battery thermal propagation. For example, if a first battery