Battery Cell Blocking Layers for Delayed Thermal Propagation
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Solution Overview
Problem
Lithium-ion battery cells are prone to thermal runaway, which can lead to rapid heat propagation and pose safety risks, especially in high-energy density cells like those containing silicon or lithium metal, due to their lower heat capacity and potential for uncontrolled fires.
Innovation Solution
Implementing a blocking device (BLD) with a thermally insulating layer composed of ceramic fibers and phase change materials to prevent heat transfer between cells, using materials that maintain thermal stability up to 1800°C and activate before thermal runaway conditions, thereby delaying heat propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high energy density cell materials (silicon, lithium metal) are used to increase energy capacity, then the energy capacity is improved, but the heat capacity decreases and thermal runaway risk increases
Solution Approach 1:
A blocking device is introduced as an intermediary component between adjacent battery cells. This device includes a thermally insulating layer that acts as a mediator to prevent direct heat transfer between cells, and a blocking layer containing fire suppressant materials that actively inhibit thermal runaway propagation. The intermediary device allows high energy density materials to be used while providing a protective barrier against thermal hazards.
Solution Approach 2:
The blocking device is segmented into distinct functional layers: a thermally insulating layer for heat blocking and a blocking layer with fire suppressant materials for active thermal runaway inhibition. This segmentation allows each layer to specialize in a specific protective function, optimizing both thermal insulation and fire suppression capabilities while maintaining compatibility with high energy density cell materials.
2Reliability
If thermally insulating blocking devices are added between cells to prevent heat propagation, then thermal safety is improved, but device complexity increases
Solution Approach 1:
Multiple protective functions are merged into a single integrated blocking device structure. The thermally insulating layer and the blocking layer with fire suppressant materials are combined in one device that fits between adjacent cells. This merging approach provides both thermal insulation and active fire suppression without requiring separate independent systems, thereby limiting the increase in device complexity.
Solution Approach 2:
The blocking device is designed as a multi-functional component that simultaneously provides thermal insulation, fire suppression, and structural support between cells. By consolidating multiple safety functions into a single universal device, the patent avoids the need for multiple separate components, thus improving thermal safety while minimizing the increase in overall device complexity.
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 BLD significantly increases the time required for heat propagation, reducing maximum temperatures by over 400°C and enhancing safety by preventing fire spread between cells.
Implementation Method 1
a blocking device (BLD) with a thermally insulating layer composed of ceramic fibers
Implementation Method 2
phase change materials to prevent heat transfer between cells
Implementation Method 3
using materials that maintain thermal stability up to 1800°C and activate before thermal runaway conditions
Data Source
AI summary
This disclosure describes a battery device with one or more battery cells and an insulation layer that reduces and/or delays thermal propagation. The insulating layer may be hermetically sealed into the cell. The insulating layer may be thermally stable up to 1800° C. The insulating layer may have a thermal conductivity less than 1 W/(m·K). The insulating layer may comprise a ceramic material. For example, the insulating layer may comprise a porous ceramic paper that is saturated or coated with another material.