Battery Cell Thermal Barrier With Gas-Venting Insulation
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Solution Overview
Problem
Lithium ion batteries in electric vehicles are prone to thermal runaway events, leading to overheating and destruction, and existing solutions do not effectively prevent or slow down these events.
Innovation Solution
A thermal runaway barrier comprising a nonwoven fibrous thermal insulation with fumed silica particles and a binder, encapsulated in an organic and optional inorganic layer with vent holes to allow gas escape, is integrated between battery cells to mitigate overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal insulation material is used to slow down thermal runaway, then thermal protection is improved, but gas accumulation may compromise structural integrity
Solution Approach 1:
The encapsulation layer is designed with a porous structure containing multiple voids or channels that allow gas to escape during thermal runaway events. This porous architecture maintains the structural integrity of the encapsulation layer while providing a pathway for gas venting, thus resolving the contradiction between thermal protection and structural strength.
Solution Approach 2:
The barrier comprises a composite structure with an encapsulation layer made from thermally insulative material that incorporates gas-venting pathways. The composite nature allows simultaneous achievement of thermal insulation properties and structural integrity through integrated gas escape routes.
2Strength
If the encapsulation layer is made completely sealed to maintain structural integrity, then strength is improved, but gas accumulation occurs during thermal runaway
Solution Approach 1:
The encapsulation layer incorporates a porous structure with voids or channels that provide gas escape pathways while maintaining overall structural integrity. The porous architecture allows gas to vent during thermal runaway without compromising the strength of the encapsulation layer.
Solution Approach 2:
The porous structure acts as an intermediary mechanism within the encapsulation layer, providing a controlled pathway for gas to escape while the surrounding solid matrix maintains structural integrity. This intermediary structure resolves the conflict between sealing for strength and allowing gas escape.
3Object-generated harmful factors
If vent holes are added to allow gas escape, then gas venting is improved, but structural integrity may be compromised
Solution Approach 1:
Rather than adding discrete vent holes that compromise structural integrity, the encapsulation layer is designed with an integrated porous structure containing multiple voids or channels. This porous architecture provides gas escape pathways while the distributed nature of the voids maintains overall structural strength.
Solution Approach 2:
The gas venting function is segmented into multiple distributed voids or channels throughout the encapsulation layer rather than relying on a single large vent hole. This segmentation allows gas escape while distributing stress and maintaining structural integrity across the entire layer.
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 slows down thermal runaway events by providing thermal insulation and allowing gas escape, thereby maintaining structural integrity and preventing damage to battery cells.
Implementation Method 1
a layer of a nonwoven fibrous thermal insulation comprising a fiber matrix of inorganic fibers, thermally insulative inorganic particles comprising fumed silica dispersed within the fiber matrix
Implementation Method 2
The organic encapsulation layer has at least one vent hole formed therethrough that is located and sized to allow gas contained within the thermal runaway barrier to escape from the organic encapsulation
Data Source
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AI summary
A thermal runaway barrier for at least significantly slowing down a thermal runaway event within a battery assembly. The thermal runaway barrier includes a layer of a nonwoven fibrous thermal insulation comprising a fiber matrix of inorganic fibers, thermally insulative inorganic particles of fumed silica dispersed within the fiber matrix, and a binder dispersed within the fiber matrix so as to hold together the fiber matrix. An optional organic encapsulation layer may also be used to encapsulate the nonwoven fibrous thermal insulation.