eVTOL Battery Vent Flap Assembly for Thermal Runaway Pressure Relief
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Solution Overview
Problem
Electric vertical take-off and landing (eVTOL) aircraft face challenges in safely managing thermal runaway in battery cells, which can lead to uncontrolled heat and gas release, posing risks to the aircraft and its occupants.
Innovation Solution
A mechanical support layer with integrated vent flaps is attached to the battery assembly, allowing the vent flaps to deform and safely release gas from battery cells, thereby preventing pressure buildup and protecting adjacent cells from heat and ejecta during thermal runaway events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery cells are sealed to prevent heat and gas release, then thermal runaway propagation is reduced, but pressure buildup occurs causing cell damage
Solution Approach 1:
The vent flap layer is divided into multiple individual vent flaps, each corresponding to a specific battery cell. This segmentation allows controlled venting for individual cells experiencing thermal runaway while maintaining sealing for other cells, resolving the contradiction between preventing thermal runaway propagation and releasing pressure.
Solution Approach 2:
The vent flap acts as an intermediary component between the sealed battery cell and the external environment. It provides a controlled interface that allows selective gas and heat release while maintaining overall system sealing, preventing both uncontrolled thermal runaway propagation and dangerous pressure buildup.
2Strength
If vent flaps are made rigid to maintain structural integrity, then mechanical strength is improved, but controlled deformation for gas release is reduced
Solution Approach 1:
The vent flap layer combines regions of different rigidity: the overall layer structure maintains structural integrity through the support layer attachment, while local regions (the vent flaps themselves) are designed with controlled flexibility to deform under thermal runaway pressure. This local quality differentiation resolves the contradiction between structural strength and deformation capability.
Solution Approach 2:
The vent flap transitions from a static rigid structure to a dynamic component that changes its state based on thermal conditions. Under normal operation, the vent flap remains rigid and sealed; during thermal runaway, it deforms to allow controlled venting, providing adaptability while maintaining structural integrity.
3Reliability
If battery assembly is tightly sealed to protect adjacent cells, then thermal runaway propagation is prevented, but pressure buildup damages cells
Solution Approach 1:
The vent flap converts the harmful effect of pressure buildup during thermal runaway into a beneficial controlled release mechanism. By allowing controlled deformation and venting, the system transforms the dangerous pressure that would otherwise damage cells into a protective function that releases harmful gases and heat while preventing thermal runaway propagation to adjacent cells.
4Stress or pressure
If vent flaps are made flexible to allow gas release, then pressure relief is improved, but mechanical support and structural stability are reduced
Solution Approach 1:
The vent flap layer is merged with the mechanical support layer through attachment at specific regions. This combination allows the vent flap to provide flexibility for pressure relief where needed while the mechanical support layer provides overall structural stability. The merging of these two functional layers resolves the contradiction between pressure relief and mechanical support.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively manages thermal runaway by allowing controlled gas release, reducing the risk of cell damage and ensuring the safety of the aircraft and its occupants by preventing pressure buildup and heat transfer between cells.
Implementation Method 1
Each vent flap includes one or more portions configured to deform to permit flow of gas from the battery cell corresponding to the vent flap
Data Source
AI summary
This disclosure relates generally to high voltage power supply (HVPS) systems and battery assemblies for aircraft that use electrical propulsion systems. In one embodiment, an apparatus for safely venting battery cells in thermal runaway is provided. The apparatus includes: a mechanical support layer, the mechanical support layer configured to be attached to a battery assembly; and a vent flap layer attached to the mechanical support layer, the vent flap layer including vent flaps corresponding to battery cells in the battery assembly. Each vent flap includes one or more portions configured to deform to permit flow of gas from the battery cell corresponding to the vent flap.