Insulated Pouch Cell Encapsulation for Thermal Runaway Resistance
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Solution Overview
Problem
Lithium-ion batteries are susceptible to thermal runaway under abuse conditions, leading to safety hazards such as fire or explosion, and existing methods to mitigate this, like insulation between cells, limit energy density or are combustible.
Innovation Solution
Incorporating an insulation layer into the encapsulation material of pouch battery cells, comprising a laminate film with an inner polymer layer, an insulation layer, and an outer polymer layer, which can include a malleable layer for additional protection, to prevent heat transfer and propagation during thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulation material is added between cells to prevent thermal runaway propagation, then safety is improved, but energy density is reduced due to volume occupied by insulation
Solution Approach 1:
The patent merges the insulation function with the encapsulation layer by integrating an insulation layer into the laminate structure that already surrounds each cell. This combines thermal protection with mechanical encapsulation functions into a single integrated component, eliminating the need for separate insulation materials between cells and preserving energy density while maintaining safety.
Solution Approach 2:
The encapsulation layer is designed to serve multiple functions simultaneously: mechanical protection, sealing, and thermal insulation. By making the encapsulation layer multi-functional, the patent eliminates the need for additional dedicated insulation components, thereby maintaining high energy density while providing thermal runaway protection.
2Reliability
If phase change materials are used for cooling, then thermal runaway is mitigated, but the materials are combustible and cannot prevent fire propagation
Solution Approach 1:
The patent addresses the combustibility issue by selecting insulation materials with inherently low combustibility or non-combustible properties. Rather than trying to make combustible phase change materials safer, the invention uses materials like aerogels or intumescent coatings that provide thermal insulation while resisting combustion, effectively converting the thermal management challenge into a safety advantage.
Solution Approach 2:
The patent changes the material parameter of combustibility by selecting insulation materials with fire-resistant properties. Instead of using combustible phase change materials, the invention employs materials with high thermal stability and low flammability, fundamentally altering the fire safety parameters of the thermal management system.
3Reliability
If intumescent materials are used for insulation, then thermal protection is provided, but the expansion of material must be accounted for in design
Solution Approach 1:
The patent applies intumescent materials as thin coating layers on the encapsulation structure before cell assembly. By applying the insulation layer in advance during manufacturing, the design accounts for the material's final state rather than its expanded state, simplifying the overall design process while maintaining thermal protection benefits.
4Reliability
If aerogel thermal barriers are used, then heat propagation resistance is improved, but the light weight and low stiffness make installation difficult
Solution Approach 1:
The patent uses aerogel-based thin film coatings or flexible composite structures that maintain the excellent thermal insulation properties of aerogel while providing sufficient mechanical strength and stiffness for easy handling and installation. This approach retains the heat propagation resistance benefit while overcoming the mechanical weakness of pure aerogel.
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 insulation layer effectively minimizes thermal runaway propagation without significantly impacting energy density or increasing assembly costs, providing favorable thermal and mechanical properties for compressibility and resilience.
Implementation Method 1
the insulation layer effectively minimizes thermal runaway propagation without significantly impacting energy density or increasing assembly costs, providing favorable thermal and mechanical properties for compressibility and resilience
Data Source
AI summary
The present disclosure relates to materials and systems to manage thermal runaway issues in energy storage systems. Exemplary embodiments include an insulation layer that is placed in the encapsulation material used to encapsulate a pouch battery cell. The encapsulation layer for a pouch battery cell is made from a laminate film that comprises an insulation layer.