Battery thermal runaway suppression and directional flow exhaust system for replaceable battery manned multicopter

Abstract

The application relates to the technical field of power battery safety protection, and discloses a battery thermal runaway suppression and directional flow exhaust system of a replaceable manned multi-rotor aircraft, which comprises a modular battery accommodating cabin, a pluggable power battery module and a directional flow exhaust system. A plurality of cell matrix intervals are arranged in a high-strength explosion-proof shell of the power battery module, ceramicized silicone rubber thermal barrier layers are arranged between adjacent intervals, and a multistage explosion-proof membrane group with different opening pressure differences is arranged on the side wall of the shell. After the power battery module is installed in place, the multistage explosion-proof membrane group is in sealed communication with a drainage air inlet, and the gas and ejection material generated by thermal runaway are discharged to a predetermined discharge area below the aircraft body through a drainage pipeline. A plurality of physical isolation barriers are arranged between the modular battery accommodating cabin and a passenger cabin, so that the risk of heat and smoke transmission to the passenger cabin is reduced.

Description

Technical Field

[0001] This invention relates to the field of power battery safety protection technology, and more specifically, to a battery thermal runaway suppression and directional exhaust system for a swappable manned multi-rotor aircraft. Background Technology

[0002] With the development of urban air mobility and electric vertical takeoff and landing (eVTOL) aircraft, power batteries have become the main energy source for manned multirotor aircraft. To shorten the ground refueling time of aircraft, modular power batteries and standardized docking interfaces can be used, allowing the power battery modules to be replaced from the bottom of the aircraft fuselage.

[0003] Swappable power battery modules need to withstand high-rate discharge, flight vibration, ambient temperature changes, and repeated insertion and removal during operation. When a cell experiences an internal short circuit, overcharging, or abnormal temperature rise, it may generate high-temperature gas, flammable gas, and ejected material, causing a rapid increase in internal pressure of the power battery module.

[0004] Existing power battery protection structures typically focus on battery module installation, conventional heat dissipation, or mechanical protection. When a power battery module experiences thermal runaway, some structures lack sealed pressure relief interfaces that mate with the pluggable battery module, making it difficult to expel gases and ejected materials generated by thermal runaway along a predetermined path. Furthermore, the thermal and smoke isolation capabilities between the power battery module and the crew cabin still have room for improvement. Therefore, there is a need for a battery thermal runaway suppression and directional exhaust system suitable for swappable battery manned multirotor aircraft. Summary of the Invention

[0005] This invention addresses the technical problems existing in the prior art by providing a battery thermal runaway suppression and directional exhaust system for a swappable manned multi-rotor aircraft. This system solves the technical problems in the prior art, such as lack of pressure management, uncontrolled diffusion of high-temperature ejected materials, lack of active suppression methods, and inadequate crew cabin isolation under thermal runaway conditions.

[0006] This invention provides a battery thermal runaway suppression and directional exhaust system for a swappable manned multirotor aircraft, comprising a modular battery housing located at the bottom of the aircraft fuselage, a power battery module detachably mounted within the modular battery housing via a sliding rail guide mechanism, and a directional exhaust system located on the outer edge of the modular battery housing; the power battery module includes a high-strength explosion-proof outer shell, the internal space of which is divided into multiple cell matrix sections, with a ceramicized silicone rubber thermal barrier layer between adjacent cell matrix sections; the high-strength explosion-proof outer shell... The sidewall of the shell is provided with at least one set of multi-level explosion-proof membrane groups, each set of multi-level explosion-proof membrane groups including at least two pressure relief units with different opening pressure differences; the inner wall of the modular battery housing is provided with a drainage air inlet corresponding to the multi-level explosion-proof membrane group; when the power battery module is inserted into the locking position along the slide rail guide mechanism, the multi-level explosion-proof membrane group is aligned with the corresponding drainage air inlet and sealed and connected; the directional flow exhaust system is connected to the drainage air inlet through a drainage pipe, and is used to guide the gas and ejected material generated by the thermal runaway of the power battery module to a predetermined emission area under the aircraft body.

[0007] In one embodiment of the present invention, the high-strength explosion-proof shell of the power battery module is made of polyphenylene sulfide combined with 30% carbon fiber reinforcement material, and its tensile strength is not less than 150 MPa. An aerosol fire extinguishing medium release unit is provided inside the cell matrix section. The aerosol fire extinguishing medium release unit includes a solid aerosol generator, a temperature sensing self-triggering mechanism, and a release outlet. When the fusible alloy locking part melts, the temperature sensing self-triggering mechanism triggers the solid aerosol generator to produce potassium salt-based fire extinguishing aerosol, which enters the cell matrix section through the release outlet.

[0008] Furthermore, the multi-stage explosion-proof membrane assembly includes a first-stage low-pressure relief membrane and a second-stage high-pressure rupture disc. The opening pressure differential of the first-stage low-pressure relief membrane is set to 0.05 MPa to 0.08 MPa to discharge small amounts of gas generated by the battery module during overcharging or early high-temperature conditions. The opening pressure differential of the second-stage high-pressure rupture disc is set to 0.3 MPa to 0.5 MPa to rapidly release a high-pressure shock wave at the moment of thermal runaway. The second-stage high-pressure rupture disc adopts a stainless steel indented sheet structure to ensure instantaneous full-section opening when the preset pressure is reached.

[0009] Furthermore, the directional exhaust system includes a composite material exhaust manifold integrated inside the aircraft landing gear struts. The inner surface of the composite material exhaust manifold is coated with an ultra-high temperature ceramic heat-insulating coating with a thickness of 1.5 mm to 2.5 mm. This coating can protect the manifold structure from melting and breaking down under the impact of a momentary eruption flame at 1200 degrees Celsius. The outlet end of the composite material exhaust manifold is equipped with a Venturi effect nozzle, which utilizes the relative negative pressure formed at the nozzle outlet by the high-speed airflow during flight to accelerate the extraction efficiency of gases generated by high-temperature thermal runaway in the battery compartment.

[0010] In one embodiment of the present invention, an automatic docking interface is provided between the modular battery housing and the power battery module. The automatic docking interface includes a high-voltage power transmission interface and a fire extinguishing medium supply interface. The high-voltage power transmission interface adopts a detachable floating blind-plug structure and is configured to disconnect after the high-voltage bus circuit is cut off, following the removal of the power battery module. The fire extinguishing medium supply interface adopts a detachable interface structure and is equipped with a self-sealing valve. When the fire extinguishing medium supply interface is connected, the self-sealing valve opens, connecting the fire extinguishing pipeline inside the power battery module with the fire extinguishing medium supply pipeline inside the aircraft fuselage. When the fire extinguishing medium supply interface is disconnected, the self-sealing valve automatically closes to reduce fire extinguishing medium leakage.

[0011] The aircraft fuselage is equipped with a clean gas fire extinguishing medium storage tank, which is connected to the fire extinguishing pipeline inside the power battery module via a supply solenoid valve and the fire extinguishing medium replenishment interface. When the system detects a thermal runaway signal from the power battery module, the flight control system controls the supply solenoid valve to open, thereby delivering fire extinguishing medium into the power battery module.

[0012] Furthermore, the top of the modular battery housing, i.e., the side closest to the passenger compartment, is equipped with a multi-layered physical barrier consisting of a nanoporous heat insulation plate and a titanium alloy sheet. The nanoporous heat insulation plate has a thermal conductivity of less than 0.02 watts per meter Kelvin at room temperature. This multi-layered physical barrier design ensures that even in the event of a sustained and intense combustion of the battery module, the temperature increase conducted to the passenger compartment floor will not exceed 40 degrees Celsius within 30 minutes, providing the occupants with sufficient time for emergency evacuation.

[0013] Furthermore, a pressure monitoring sensor array is installed in the pressure relief channel between the air intake and the drainage pipe. The pressure monitoring sensor array includes at least four pressure sensors, the response time of which is less than the sampling period of the pressure monitoring sensor array, and the sampling frequency of the pressure monitoring sensor array is 1000Hz. The flight control system calculates the pressure rise gradient based on the pressure data collected by the pressure monitoring sensor array; when the pressure rise gradient exceeds a preset gradient threshold for at least three consecutive sampling periods, the flight control system determines that the power battery module has entered the thermal runaway stage and disconnects the high-voltage bus circuit.

[0014] As one embodiment of the present invention, each cell matrix section of the power battery module is embedded with a phase change material heat absorption layer. The latent heat of phase change of the phase change material is not less than 200 kJ per kilogram, and the phase change temperature is set to 65 degrees Celsius to 75 degrees Celsius. The phase change material heat absorption layer assists in heat dissipation under normal high-rate discharge conditions and absorbs a large amount of heat dissipation energy in the early stage of thermal runaway, thus delaying the heat diffusion process.

[0015] Furthermore, the aerodynamic layout of the end outlet of the directional exhaust system has been optimized. The angle between the exhaust vector direction of the end outlet and the downwash airflow of the aircraft's main rotor is set to 15 to 30 degrees. Through the strong dilution effect of the downwash airflow, the concentration of toxic fumes emitted is rapidly reduced, preventing the fumes from drifting upwards to the air inlet or the sensor's field of view, thus ensuring the normal operation of the aircraft's sensing system.

[0016] Furthermore, the opening of the modular battery compartment is equipped with an electromagnetic engagement locking mechanism and a resilient ejector. When the flight control system determines that the thermal runaway severity of the power battery module has reached a preset critical level and the high-voltage bus circuit has been disconnected, the flight control system controls the electromagnetic engagement locking mechanism to perform a controlled power-off release action; after the lock is released, the resilient ejector applies an outward pushing force along the slide rail guide mechanism to the power battery module, causing the power battery module to detach from the modular battery compartment along the slide rail guide mechanism.

[0017] In one embodiment of the present invention, the bottom of the outer casing of the power battery module is provided with an energy-absorbing honeycomb structure. When the battery module is urgently thrown to the landing site, the energy-absorbing honeycomb structure absorbs the impact kinetic energy through its own plastic deformation, reducing the risk of casing damage and preventing secondary pollution or fire spread.

[0018] Furthermore, the system also includes an air quality safety monitoring unit located inside the crew cabin. This unit includes a carbon dioxide sensor, a carbon monoxide sensor, and a volatile organic compound detector. The air quality safety monitoring unit is communicatively connected to the flight control system via a controller area network bus. When the concentration of at least one monitored gas reaches a corresponding preset alarm threshold, or when the flight control system determines that the power battery module has entered the thermal runaway phase, the flight control system activates the crew cabin positive pressure maintenance system, introducing filtered clean air into the crew cabin through an independent positive pressure air supply device to reduce the probability of harmful gases entering the crew's breathing area.

[0019] Furthermore, the composite material exhaust manifold of the directional flow exhaust system is equipped with an acoustic monitoring probe. This probe collects the acoustic signals generated when the depressurized gas flows through the composite material exhaust manifold after the first-stage low-pressure relief diaphragm opens. The flight control system identifies changes in exhaust intensity based on the spectral characteristics of the acoustic signals and outputs an escalation warning signal when it detects abnormal spectral characteristics corresponding to the risk of the second-stage high-pressure rupture disc opening.

[0020] Furthermore, the communication cables and sensor cables inside the power battery module are fire-resistant cables to reduce the risk of premature circuit failure under high-temperature conditions of thermal runaway.

[0021] Furthermore, the outlet end of the composite material exhaust manifold is provided with a protective grid, which is used to reduce the risk of external sparks being transmitted back to the power battery module along the composite material exhaust manifold.

[0022] Furthermore, the nozzle material of the directional exhaust system is made of carbon fiber reinforced carbon matrix composite material, which has high temperature resistance and ablation resistance, reducing structural damage caused by high temperature erosion.

[0023] The present invention provides a battery thermal runaway suppression and directional exhaust system for a swappable manned multirotor aircraft, which has the following advantages compared with the prior art: (1) The multi-level explosion-proof membrane of the power battery module is sealed and connected to the air inlet after the power battery module is installed in place, so that the gas and ejected material generated by thermal runaway can be discharged to the lower part of the aircraft body through the drainage pipe, reducing the risk of the pressure relief medium spreading to the crew cabin.

[0024] (2) A ceramicized silicone rubber thermal barrier layer is installed between adjacent cell matrix sections, and a fire extinguishing medium release unit is installed in the power battery module, which helps to slow down the spread of heat between adjacent cell matrix sections. Multiple physical barriers are installed between the modular battery housing and the passenger compartment to slow down the transfer of heat to the passenger compartment floor.

[0025] (3) The pressure monitoring sensor array is used to collect pressure changes in the pressure relief channel. The flight control system performs high-voltage bus disconnection, active fire suppression, positive pressure maintenance of the crew cabin, and power battery module disconnection control under extremely dangerous conditions according to the pressure rise gradient, thereby improving the orderliness of the thermal runaway emergency response process. Attached Figure Description

[0026] Figure 1 This is a schematic diagram showing the main components and functional relationships of the battery thermal runaway suppression and directional exhaust system for the swappable manned multi-rotor aircraft proposed in this invention. Figure 2 This is a schematic diagram illustrating the functional relationship between the high-strength explosion-proof shell, the battery cell matrix area, the multi-stage explosion-proof membrane group, the air inlet, and the directional airflow exhaust system of the present invention. Figure 3 This is a schematic diagram of the control process of the present invention, including pressure monitoring, thermal runaway determination, high-voltage bus disconnection, active suppression, positive pressure maintenance of the passenger compartment, and emergency disconnection of the power battery module.

[0027] It should be noted that, Figure 1 and Figure 2 The arrows in the diagram are used to indicate inclusion, connectivity, or functional relationships between components, and are not used to define the actual dimensions, spatial proportions, or specific installation directions of the components. The pressure relief medium generated after the opening of the first-stage low-pressure relief diaphragm and the second-stage high-pressure rupture disc both enter the composite material exhaust manifold through the inlet and are discharged through the Venturi effect nozzle. Figure 2 The different branches do not indicate that the first-stage low-pressure relief diaphragm and the second-stage high-pressure rupture disc are connected separately to different exhaust components.

[0028] Figure 3 In the process, when the pressure rise gradient does not reach the preset gradient threshold, the pressure monitoring sensor array continues to sample pressure data; Figure 3 The phrase "triggering the release of aerosol extinguishing medium" indicates that the system has entered the active suppression phase. The aerosol extinguishing medium release unit inside the power battery module is triggered by a temperature-sensing self-triggering mechanism, while the flight control system controls the external extinguishing medium replenishment process. Figure 3 The phrase "emergency detachment of power battery module" corresponds to the emergency detachment process of power battery module described in this manual. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In addition, the technical features of the various embodiments or individual embodiments provided by the present invention can be arbitrarily combined with each other to form feasible technical solutions. Such combinations are not constrained by the order of steps and / or structural composition patterns, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0030] Example 1: Please refer to the attached document. Figure 1 This embodiment provides a battery thermal runaway suppression and directional decompression system for a swappable manned multirotor aircraft. Its core design addresses the extreme safety requirements of manned multirotor aircraft in high-energy-density power battery application scenarios. It constructs a thermal runaway safety handling structure encompassing microscopic cell thermal isolation, macroscopic module pressure management, and active protection of the fuselage structure. Integrated into the aircraft's chassis load-bearing structure, this system aims to minimize the impact on the crew cabin and flight control in the event of uncontrollable thermal runaway through coordinated action of multiple dimensions, including physical isolation, active suppression, directional decompression, and emergency disengagement. This maximizes the survival environment of the crew cabin and the emergency control capabilities of the aircraft.

[0031] The physical carrier of the system includes a modular battery compartment located at the bottom of the aircraft fuselage. This modular battery compartment uses a lightweight, high-strength aluminum-lithium alloy frame as its main skeleton, with reinforcing ribs integrated into its side walls to cope with structural stresses during high-load flight. The internal space of the modular battery compartment is connected via a sliding rail guide mechanism for quick plug-and-play connection with the power battery module. The power battery module, as the core energy unit of the aircraft, is encased in a high-strength explosion-proof shell. This high-strength explosion-proof shell is made of polyphenylene sulfide combined with 30% carbon fiber reinforcement through high-pressure injection molding. This material selection ensures that the shell has a tensile strength of no less than 150 MPa at room temperature and maintains more than 85% structural rigidity even at 200 degrees Celsius, preventing tearing of the shell due to sudden increases in internal pressure.

[0032] Inside the high-strength explosion-proof enclosure, the internal space is divided into multiple cell matrix sections. Each cell matrix section contains an array of several high-energy-density lithium-ion cells. To cut off the heat conduction path between the cells and prevent a chain reaction caused by local short circuits, a ceramicized silicone rubber thermal barrier layer is filled between adjacent cell matrix sections. Under normal conditions, this ceramicized silicone rubber thermal barrier layer exhibits flexible damping characteristics, but when subjected to flame erosion at temperatures above 500 degrees Celsius, its surface rapidly undergoes a ceramicization reaction, forming an inorganic ceramic layer, thereby slowing the diffusion of heat to adjacent cell matrices.

[0033] Combined with appendix Figure 2 As shown, to cope with the large amount of high-temperature and high-pressure gas generated during battery thermal runaway, this embodiment designs a multi-stage explosion-proof membrane assembly on the side wall of the high-strength explosion-proof shell. The multi-stage explosion-proof membrane assembly consists of at least two pressure relief units with different pressure relief thresholds, specifically including a first-stage low-pressure relief membrane and a second-stage high-pressure rupture disc. The first-stage low-pressure relief membrane is made of polyimide composite material, with its opening pressure differential preset between 0.05 MPa and 0.08 MPa. This stage is mainly designed to address the small amount of volatile gas generated by the battery under overcharging, over-discharging, or extreme high-temperature environments, preventing potential hazards caused by pressure buildup inside the shell through timely venting. The second-stage high-pressure rupture disc is made of stainless steel and has undergone precision laser engraving, with its rupture opening pressure differential set between 0.3 MPa and 0.5 MPa. When severe thermal runaway occurs inside the cell and the internal pressure rises at an extremely high gradient, the second-stage high-pressure rupture disc will achieve instantaneous full-section opening, allowing high-pressure gas and ejected materials to be discharged along a preset path.

[0034] The inner wall of the modular battery housing is provided with an air inlet, which is aligned with the multi-stage explosion-proof membrane assembly on the power battery module. When the power battery module is pushed into the preset locking position along the slide rail guide mechanism, the alignment deviation between the multi-stage explosion-proof membrane assembly and the central axis of the air inlet is no more than 1.0 mm. The high-temperature resistant flexible sealing ring located around the air inlet is compressed and undergoes a compression deformation of about 2 mm, forming a sealed pressure relief channel between the multi-stage explosion-proof membrane assembly and the air inlet. Preferably, the sealing contact part of the high-temperature resistant flexible sealing ring is located on the periphery of the main channel of the pressure relief medium to reduce the direct impact of high-temperature gas and ejected materials generated by thermal runaway on the high-temperature resistant flexible sealing ring.

[0035] The directed exhaust system is connected to the intake port via a drainage pipe, and is used to guide the gas, smoke, and ejecta generated by the thermal runaway of the power battery module to a predetermined emission area under the aircraft fuselage. The drainage pipe is integrated inside the aircraft landing gear strut to utilize the internal space of the landing gear strut to form an exhaust path.

[0036] The drainage pipe is a composite material exhaust manifold, the inner surface of which is coated with a ceramic thermal insulation coating with a thickness of 1.5 mm to 2.5 mm. This ceramic thermal insulation coating is formed from yttrium-stabilized zirconium oxide using a plasma spraying process, and is used to reduce the thermal shock and erosion of the composite material exhaust manifold substrate by the high-temperature gases and ejected materials generated during thermal runaway. The outlet end of the composite material exhaust manifold is equipped with a Venturi effect nozzle. When the aircraft is in flight with forward velocity, the external airflow flowing through the landing gear area creates a relatively low pressure at the outlet of the Venturi effect nozzle, promoting the discharge of gases and ejected materials generated during thermal runaway along the composite material exhaust manifold.

[0037] In this core technology, the system calculates the pressure rise gradient within the pressure relief channel in real time. A pressure monitoring sensor array, comprising at least four pressure sensors, is installed within the pressure relief channel between the air intake and the drainage pipe. The response time of each pressure sensor is less than the sampling period, and the sampling frequency is set to 1000Hz. The flight control system calculates the pressure rise gradient using the following algorithm:

[0038] In the formula, This represents the pressure gradient, measured in megapascals per second. This represents the pressure value collected at the current moment; This represents the pressure value from the previous sampling period; This represents the sampling time interval. When... When the preset gradient threshold is exceeded for at least three consecutive sampling cycles, the flight control system determines that the power battery module has entered the thermal runaway stage and executes the high-voltage bus disconnection logic, thus entering the active suppression and thermal runaway risk level assessment process.

[0039] For active suppression, each cell matrix section is embedded with an aerosol extinguishing medium release unit. This aerosol extinguishing medium release unit integrates a temperature-sensing self-triggered mechanism, which can operate independently without electronic signal intervention. When the local ambient temperature rises to the range of 170 to 190 degrees Celsius, the fusible alloy within the temperature-sensing self-triggered mechanism melts, releasing a high concentration of potassium-based aerosol. The extinguishing aerosol reduces the flame chain reaction rate through chemical inhibition, thereby suppressing visible flames and slowing the propagation of thermal runaway.

[0040] Furthermore, the power battery module is also designed with a heat-absorbing layer based on a phase change material. The phase change material is a microencapsulated paraffin composite material with a phase change temperature set between 65 and 75 degrees Celsius and a latent heat of phase change of no less than 200 kilojoules per kilogram. Under normal flight conditions with high-rate current output, this heat-absorbing layer can absorb excess heat generated by the battery cell, maintaining the battery within its optimal operating temperature range. In the early stages of thermal runaway, the phase change material absorbs a large amount of latent heat through solid-liquid phase change, providing valuable response time for system early warning and active suppression.

[0041] In one embodiment, the exhaust outlet of the directional flow exhaust system is angled relative to the downwash airflow direction of the aircraft's main rotor. The vector direction of the exhaust pipe's final outlet forms an angle of 15 to 30 degrees with the downwash airflow direction of the aircraft's main rotor. This angle allows the gas exhausted from the Venturi effect nozzle to enter the main rotor's downwash flow field, promoting the dilution and downward transport of the exhaust gas and reducing the probability of toxic or combustible gases flowing back into the crew cabin air intake or the area where flight sensing sensors are located.

[0042] For manned aircraft, it is necessary to reduce the risk of heat and smoke transfer to the crew compartment. Therefore, a multi-layered physical barrier consisting of a nanoporous heat insulation panel and a titanium alloy sheet is installed between the modular battery housing and the bottom of the crew compartment. The nanoporous heat insulation panel has an extremely low thermal conductivity at room temperature, only 0.018 watts per meter Kelvin. This composite structure ensures that even if the power battery module undergoes continuous and intense combustion at the bottom, the rate at which heat is conducted to the crew compartment floor through radiation and convection is significantly reduced.

[0043] The system also integrates an air quality safety monitoring unit located inside the crew cabin. This unit is equipped with highly sensitive carbon monoxide sensors, carbon dioxide sensors, and total volatile organic compound (TVOC) detectors. These detectors are connected to the flight control system via a highly reliable controller area network (CLAN) bus. Once the concentration of at least one monitored gas reaches the corresponding preset alarm threshold, or if the flight control system determines that the power battery module has entered a thermal runaway phase, the flight control system activates the crew cabin positive pressure maintenance system. This system introduces filtered clean air into the crew cabin through an independent positive pressure air supply device to establish a slightly positive pressure environment relative to the outside environment, reducing the probability of harmful gases entering the crew's breathing zone.

[0044] When the risk of thermal runaway continues to rise, and the flight control system determines that the severity of thermal runaway of the power battery module has reached a preset critical level that may affect the structural safety of the aircraft, the flight control system executes emergency disengagement control in the following order: high-voltage circuit disconnection, cessation of fire extinguishing medium supply, release of locking mechanism, separation of automatic docking interface, and removal of power battery module.

[0045] First, the flight control system disconnects the high-voltage bus circuit, placing the high-voltage power transmission interface in an unloaded state. Then, the flight control system closes the supply solenoid valve located between the clean gas extinguishing medium storage tank and the extinguishing medium replenishment interface, stopping the supply of extinguishing medium to the power battery module. After completing the high-voltage circuit disconnection and the extinguishing medium supply cessation, the flight control system issues an emergency release command to the electromagnetic engagement locking mechanism located at the opening of the modular battery compartment. The electromagnetic engagement locking mechanism then performs a controlled power-off to release the lock on the power battery module.

[0046] The modular battery compartment is equipped with a resilient ejector. After the electromagnetic locking mechanism is released, the resilient ejector applies an outward pushing force along the slide rail guide mechanism to the power battery module. During the initial stage of the power battery module's outward movement along the slide rail guide mechanism, the high-voltage power transmission interface and the fire extinguishing medium supply interface disconnect as the power battery module moves; specifically, the high-voltage power transmission interface disconnects under no-load conditions, and the self-sealing valve of the fire extinguishing medium supply interface automatically closes upon interface separation. After the automatic docking interface separation is completed, the power battery module continues to move out of the modular battery compartment along the slide rail guide mechanism.

[0047] The bottom of the power battery module's outer casing is provided with an aluminum energy-absorbing honeycomb structure. When the power battery module lands, the energy-absorbing honeycomb structure absorbs part of the impact energy through plastic deformation, thereby reducing the risk of damage to the power battery module's outer casing and leakage of high-temperature internal materials.

[0048] In one optional implementation, the flight control system employs a redundant configuration of a primary control node and a backup control node. When the primary control node fails, the backup control node takes over the thermal runaway safety control functions to maintain the continuous execution of high-voltage bus disconnection, fire extinguishing medium supply, and emergency disconnection control of the power battery module. The communication cables and sensor cables inside the power battery module are fire-resistant to reduce the risk of signal transmission interruption under the high-temperature environment of thermal runaway.

[0049] Example 2: Based on Example 1, this example further illustrates the optional implementation structure of exhaust acoustic monitoring, heat-resistant exhaust manifold, and floating automatic docking interface.

[0050] To monitor the exhaust status after the first-stage low-pressure relief membrane opens, this embodiment installs an acoustic monitoring probe inside the composite material exhaust manifold of the directional flow exhaust system. The acoustic monitoring probe is used to collect the acoustic signal generated when the depressurized gas flows through the composite material exhaust manifold after the first-stage low-pressure relief membrane opens. The flight control system extracts the spectral features of the acoustic signal and determines whether the exhaust intensity continues to increase based on the extracted spectral features.

[0051] When an abnormal spectral feature corresponding to a continuous increase in exhaust intensity appears in the acoustic signal, and the abnormal spectral feature persists for a preset time, the flight control system outputs an upgrade warning signal and uses the upgrade warning signal as an auxiliary basis for judging the risk of the second-stage high-pressure rupture disc opening.

[0052] In one optional implementation, the abnormal spectral features are identified using an anomaly identification model, which may employ a one-dimensional convolutional neural network. The input features may include the Mel-frequency cepstral coefficients of the acoustic signal. The confidence threshold and duration threshold of the anomaly identification model are determined experimentally based on the power battery module type, exhaust manifold structure, and background noise conditions.

[0053] In the design of the exhaust manifold of the directional exhaust system, this embodiment uses a carbon fiber reinforced carbon-based composite material that is resistant to thermal shock. The end of the exhaust manifold is provided with a protective grid made of refractory alloy, which is used to reduce the risk of external sparks being transmitted back to the power battery module along the exhaust manifold.

[0054] This embodiment also describes the assembly compensation structure of the automatic docking interface. The automatic docking interface adopts a floating blind-fit structure, wherein the high-voltage power transmission socket is set within the modular battery housing via a multi-degree-of-freedom flexible bracket. This multi-degree-of-freedom flexible bracket can provide an assembly floating compensation of 2mm to 3mm to absorb assembly deviations during the initial insertion of the power battery module. This assembly floating compensation does not represent the alignment deviation of the pressure relief interface after the power battery module is locked in place; after the power battery module is locked in place, the deviation between the multi-stage explosion-proof membrane assembly and the central axis of the air intake is still no greater than 1.0mm.

[0055] The automatic docking interface also includes a fire extinguishing medium replenishment interface. A clean gas fire extinguishing medium storage tank inside the aircraft fuselage is connected to the fire extinguishing pipeline inside the power battery module via this interface. When the flight control system detects a thermal runaway signal from the power battery module, it controls the fire extinguishing medium supply solenoid valve to open, thereby supplying fire extinguishing medium into the power battery module.

[0056] Furthermore, this embodiment further refines the heat exchange model during thermal runaway. A multilayer radiative heat transfer correction formula is introduced when calculating the thermal insulation performance of the physical barrier:

[0057] Where q represents the radiative heat flux density per unit area; σ is the Stefan-Boltzmann constant, which has a value of 5.67 times 10 to the power of negative 8 watts per square meter in Kelvin 4. and These represent the surface temperature of the battery casing and the absolute temperature of the outer surface of the physical barrier, respectively. and The emissivity of the corresponding material is given. The net radiative heat flux density between the battery casing surface and the opposing surface of the physical barrier can be estimated using the formula, and this net radiative heat flux density is used as one of the input parameters for assessing the heat load of the physical barrier.

[0058] Example 3: Based on Embodiment 1 and Embodiment 2, this embodiment further illustrates optional implementation methods for emergency disconnection guidance of the power battery module, confirmation of battery swapping lock status, and recording of operation logs.

[0059] A disengagement guide structure is provided at the bottom of the modular battery compartment. When an emergency disengagement action is performed, the flight control system controls the electromagnetic engagement locking mechanism to release the lock on the power battery module, and the elastic push-out component located in the modular battery compartment applies a pushing force to the power battery module along the slide rail guide mechanism, causing the power battery module to move out of the modular battery compartment in the direction defined by the disengagement guide structure and the slide rail guide mechanism.

[0060] For swappable battery architectures, checking the integrity of the interfaces after each battery swap is crucial. In this embodiment, a displacement sensor is integrated into each locking claw of the modular battery housing, and the locking status is fed back to the cockpit display system in real time. Only when all locking mechanisms have reached the preset depth of locking and the air quality monitoring unit has passed its self-test can the high-voltage power distribution unit be allowed to close the main circuit.

[0061] The entire system's operational log is recorded by the onboard black box for post-flight fault analysis and maintenance assessment. The threshold for the thermal runaway detection algorithm is preset based on the test calibration results of the power battery module.

[0062] In summary, this invention utilizes a modular battery housing, a high-strength explosion-proof shell, a multi-level explosion-proof membrane assembly, a directional airflow exhaust system, and multiple layers of physical barriers to classify and handle the pressure, heat, gas, and ejected materials generated by thermal runaway of the power battery module, thereby reducing the risk of thermal runaway spreading to adjacent cell matrix areas and the passenger compartment.

[0063] During the system's manufacturing and assembly process, the mounting base for the multi-stage explosion-proof diaphragm assembly is fixed to the high-strength explosion-proof housing via a connection structure adapted to the high-strength explosion-proof housing material, and the sealing status and structural integrity of the connection points are checked. The composite material exhaust manifold can be prepared using a vacuum-assisted resin transfer molding process to reduce the impact of molding pores on the exhaust manifold's structural performance.

[0064] The system employs electromagnetic compatibility (EMC) design for the sensor signal links. The connecting cables between the pressure monitoring sensor array and the air quality safety monitoring unit can utilize shielded structures, and the relevant signal processing circuits can employ isolated power supply, filtering, and grounding measures to reduce the impact of electromagnetic interference generated by the aircraft's motor drive system on the pressure and air quality monitoring signals.

[0065] To ensure reliability during long-term use, the integrity of the multi-stage explosion-proof membrane assembly and the condition of the heat insulation coating of the directional exhaust system can be checked according to proven maintenance procedures based on the number of flight missions, battery swapping cycles, and component status.

[0066] After the power battery module is assembled, the airtightness of the high-strength explosion-proof shell and the airtightness of the multi-stage explosion-proof membrane assembly and the air inlet are tested after the power battery module is locked in place. A ceramicized silicone rubber thermal barrier layer is continuously installed between adjacent cell matrix sections, and its molding integrity is checked to reduce the impact of through-holes on the thermal barrier effect. The outer surface of the high-strength explosion-proof shell may be coated with a polytetrafluoroethylene protective coating to reduce the risk of oil and moisture contaminating or corroding the pressure relief port and the multi-stage explosion-proof membrane assembly.

[0067] For different altitudes and ambient temperatures, the flight control system acquires the external atmospheric pressure and converts the absolute pressure collected by the pressure monitoring sensor into a pressure difference relative to the external atmospheric pressure. Based on this pressure difference and its rate of change, it performs thermal runaway early warning judgment. The mechanical opening pressure difference of the multi-stage explosion-proof membrane assembly is determined by its material, thickness, and grooved structure. The flight control system does not change the actual opening pressure difference of the multi-stage explosion-proof membrane assembly; the early warning threshold can be compensated for environmental factors based on the test calibration results of the power battery module.

[0068] In the structural connections of the modular battery housing, a combination of self-locking nuts and anti-loosening washers is widely used, and high-strength thread-locking adhesive is applied. Modal analysis and structural optimization of relevant structural components can be performed based on the aircraft's vibration spectrum to reduce the risk of resonant fatigue damage during aircraft operation. The exhaust manifold of the directional exhaust system is fixed to the landing gear by a specially designed heat-resistant rubber bushing. This design can absorb the impact vibration during exhaust and achieve thermal decoupling between the pipeline and the frame.

[0069] The air quality safety monitoring unit makes a comprehensive judgment based on the concentrations and trends of carbon monoxide, carbon dioxide, and volatile organic compounds. When the comprehensive judgment result reaches a preset anomaly criterion, the flight control system activates the crew cabin positive pressure maintenance system and outputs alarm information through the crew cabin display terminal and audible prompts. The preset anomaly criterion is calibrated based on normal flight environment data and thermal runaway test data of the power battery module.

[0070] For the Venturi effect nozzle at the outlet end of the directional flow exhaust system, the profiles of its contraction and diffusion sections can be analyzed and structurally designed based on a predetermined forward flight speed range, so that the external airflow forms a relatively low pressure at the nozzle outlet within the predetermined forward flight speed range. The Venturi effect nozzle is made of a heat-shock-resistant composite material to reduce the impact of profile deformation caused by temperature changes on exhaust performance.

[0071] The electromagnetic engagement locking mechanism employs a dual-redundant coil design, with each set of coils controlled by a corresponding drive branch. In non-emergency situations, if one set of coils or its drive branch fails, the other set of coils maintains the locked state of the power battery module. When the flight control system confirms that the thermal runaway severity of the power battery module has reached a preset critical level, and the high-voltage bus circuit has been disconnected, the flight control system controls both sets of coils to perform controlled power-off to release the lock on the power battery module. After the lock is released, the elastic ejector provides an outward pushing force along the guide rail mechanism to the power battery module.

[0072] This invention employs a modular battery housing and a pluggable power battery module. Through the combination of a multi-level explosion-proof membrane, a directional exhaust system, and multiple layers of physical isolation barriers, it achieves graded depressurization and directional emission of the power battery module in the event of thermal runaway, as well as heat and smoke isolation in the crew cabin. The related structures can be adapted to multi-rotor flight platforms of different specifications and layouts.

[0073] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0074] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0075] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A battery thermal runaway suppression and directional exhaust system for a swappable manned multirotor aircraft, characterized in that, include: The modular battery compartment is located at the bottom of the aircraft fuselage and has a sliding rail guidance mechanism inside; The power battery module is detachably mounted in the modular battery housing via the slide rail guide mechanism; the power battery module includes a high-strength explosion-proof shell, the internal space of which is divided into multiple cell matrix sections, and a ceramicized silicone rubber thermal barrier layer is provided between two adjacent cell matrix sections; the sidewall of the high-strength explosion-proof shell is provided with at least one set of multi-level explosion-proof membrane groups, and each set of multi-level explosion-proof membrane groups includes at least two pressure relief units with different opening pressure differences; A directional exhaust system is provided on the outer edge of the modular battery housing. The inner wall of the modular battery housing is provided with an air inlet corresponding to the multi-stage explosion-proof membrane assembly. When the power battery module is inserted into the locking position along the slide rail guide mechanism, the multi-stage explosion-proof membrane assembly is aligned with and sealed to the corresponding air inlet. The directional exhaust system is connected to the air inlet through a drainage pipe to guide the gas and ejected material generated by the thermal runaway of the power battery module to a predetermined emission area under the aircraft body.

2. The battery thermal runaway suppression and directional exhaust system according to claim 1, characterized in that, Each of the battery cell matrix sections is equipped with an aerosol extinguishing medium release unit. The aerosol extinguishing medium release unit includes a temperature sensing self-triggering mechanism, which includes a fusible alloy locking element. When the local temperature within the battery cell matrix section reaches 170°C to 190°C, the fusible alloy locking element melts to release the locking of the aerosol extinguishing medium release unit and release the chemical inhibitor. The multi-stage explosion-proof membrane assembly includes a first-stage low-pressure relief membrane and a second-stage high-pressure rupture disc; the opening pressure difference of the first-stage low-pressure relief membrane is 0.05 MPa to 0.08 MPa; the opening pressure difference of the second-stage high-pressure rupture disc is 0.3 MPa to 0.5 MPa, and the second-stage high-pressure rupture disc has a stainless steel serrated disc structure; the opening pressure difference refers to the difference between the internal pressure of the high-strength explosion-proof shell and the pressure on the side of the air inlet. The directional exhaust system's drainage pipe is a composite material exhaust manifold integrated inside the aircraft's landing gear struts, and the inner surface of the composite material exhaust manifold is coated with an ultra-high temperature ceramic heat insulation coating with a thickness of 1.5 mm to 2.5 mm; the outlet end of the composite material exhaust manifold is equipped with a Venturi effect nozzle, and when the aircraft is in forward flight, the Venturi effect nozzle uses the external airflow flowing through the nozzle outlet to form a relatively low pressure to promote the discharge of the pressure relief medium.

3. The battery thermal runaway suppression and directional exhaust system according to claim 1, characterized in that, Each cell matrix section of the power battery module is embedded with a phase change material heat absorption layer; the phase change material heat absorption layer is made of microencapsulated paraffin composite material with a phase change latent heat of not less than 200 kJ per kilogram and a phase change temperature set at 65 degrees Celsius to 75 degrees Celsius; the phase change material heat absorption layer is used to absorb heat through solid-liquid phase change when the cell temperature reaches the phase change temperature, so as to slow down the temperature rise of the cell matrix section.

4. The battery thermal runaway suppression and directional exhaust system according to claim 2, characterized in that, The high-strength explosion-proof shell is made of carbon fiber reinforced polyphenylene sulfide composite material; the ceramicized silicone rubber thermal barrier layer undergoes a ceramicization reaction under high temperature to form an inorganic ceramic layer, thereby slowing down the transfer of heat to the adjacent cell matrix area; the ceramic heat insulation coating is formed by plasma spraying of yttrium oxide-stabilized zirconium oxide, which is used to reduce the thermal damage of the high-temperature pressure relief medium to the exhaust manifold of the composite material.

5. The battery thermal runaway suppression and directional exhaust system according to claim 1, characterized in that, An automatic docking interface is provided between the modular battery housing and the power battery module. The automatic docking interface includes a high-voltage power transmission interface and a fire extinguishing medium supply interface. A clean gas fire extinguishing medium storage tank is provided inside the aircraft fuselage. The clean gas fire extinguishing medium storage tank is connected to the fire extinguishing pipeline inside the power battery module through a supply solenoid valve and the fire extinguishing medium supply interface. The fire extinguishing medium supply interface is equipped with a self-sealing valve, which is configured to automatically close when the fire extinguishing medium supply interface is disconnected. When the airborne system detects a thermal runaway signal, the flight control system controls the solenoid valve to open to deliver fire extinguishing medium into the power battery module. The modular battery compartment is provided with a multi-layer physical barrier on the side near the passenger compartment, which consists of a nanoporous heat insulation plate and a titanium alloy thin plate. The multi-layer physical barrier is used to reduce the heat generated by the power battery module from being transferred to the passenger compartment floor.

6. The battery thermal runaway suppression and directional exhaust system according to claim 1, characterized in that, A pressure monitoring sensor array is provided in the pressure relief channel between the air intake and the drainage pipeline; the pressure monitoring sensor array includes at least 4 pressure sensors, the response time of the pressure sensors is less than the sampling period of the pressure monitoring sensor array, and the sampling frequency of the pressure monitoring sensor array is 1000Hz. The flight control system calculates the pressure rise gradient based on the pressure data collected by the pressure monitoring sensor array; when the pressure rise gradient exceeds the preset gradient threshold for at least three consecutive sampling cycles, the flight control system determines that the power battery module has entered the thermal runaway stage and cuts off the high-voltage bus circuit.

7. The battery thermal runaway suppression and directional exhaust system according to claim 1, characterized in that, The opening of the modular battery compartment is equipped with an electromagnetic attraction locking mechanism and an elastic ejector. When the flight control system determines that the thermal runaway severity of the power battery module has reached a preset critical level and the high-voltage bus circuit has been cut off, the flight control system controls the electromagnetic attraction locking mechanism to perform a controlled release action under an emergency release command. The elastic ejector applies an outward pushing force along the slide rail guide mechanism to the power battery module, causing the power battery module to detach from the modular battery compartment along the slide rail guide mechanism. The bottom of the outer shell of the power battery module is provided with an energy-absorbing honeycomb structure, which is used to absorb the impact energy when the power battery module lands through plastic deformation.

8. The battery thermal runaway suppression and directional exhaust system according to claim 2, characterized in that, The outlet axis of the Venturi effect nozzle forms an angle of 15° to 30° with the downwash airflow direction of the aircraft's main rotor, so that the gas discharged from the Venturi effect nozzle enters the downwash airflow, thereby reducing the probability of the discharged gas flowing back into the crew cabin air intake or the area where the flight sensing sensors are located.

9. The battery thermal runaway suppression and directional exhaust system according to claim 1, characterized in that, It also includes an air quality safety monitoring unit installed in the crew cabin, which includes a carbon monoxide sensor, a carbon dioxide sensor, and a volatile organic compound detector. The air quality safety monitoring unit is communicatively connected to the flight control system via a controller area network bus. When the air quality safety monitoring unit detects that the concentration of at least one monitored gas reaches the corresponding preset alarm threshold, or when the flight control system determines that the power battery module has entered the thermal runaway stage, the flight control system activates the crew cabin positive pressure maintenance system to introduce clean air into the crew cabin.

10. The battery thermal runaway suppression and directional exhaust system according to claim 2, characterized in that, An acoustic monitoring probe is installed inside the composite material exhaust manifold. The acoustic monitoring probe is used to collect the acoustic signal generated by the gas flowing through the composite material exhaust manifold after the first-stage low-pressure relief membrane is opened. The flight control system extracts the spectral characteristics of the acoustic signal and judges the change in exhaust intensity through an anomaly identification model. When an abnormal spectral characteristic corresponding to the risk of the second-stage high-pressure rupture disc being opened is identified, the flight control system outputs a warning signal.

Images