Battery Module Expansion Member for Thermal Propagation Blocking
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Solution Overview
Problem
Lithium secondary batteries are vulnerable to thermal events, which can lead to fires or explosions when multiple cells are densely packed, posing safety risks, especially in large battery packs for electric vehicles where thermal propagation can cause significant property damage and risk to life.
Innovation Solution
A battery module design incorporating an expansion member and a fire extinguishing member, where the expansion member fills empty spaces upon heat activation, potentially blocking flames and releasing extinguishing materials to suppress fires, while also managing venting and oxygen introduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple battery cells are densely packed to increase capacity, then energy density is improved, but thermal safety deteriorates due to increased vulnerability to thermal events and thermal propagation
Solution Approach 1:
The battery pack is divided into multiple independent battery modules, each surrounded by protective structures and fire-resistant materials. This segmentation isolates thermal events to specific modules, preventing propagation to other modules while maintaining high overall capacity through dense arrangement of segmented units.
Solution Approach 2:
Fire-resistant barriers and thermal insulation materials are introduced as intermediary elements between densely packed battery cells and modules. These intermediaries act as thermal shields that block heat transfer and flame propagation, enabling safe dense packing by mediating the thermal interaction between adjacent battery units.
2Stability of the object's composition
If empty spaces in the module case are left unfilled to accommodate thermal expansion, then thermal management flexibility is improved, but fire safety deteriorates due to oxygen availability and flame propagation paths
Solution Approach 1:
Empty spaces in the module case are filled with fire-resistant materials that create an inert or low-oxygen environment. These materials prevent oxygen availability for combustion and block flame propagation paths, while still allowing accommodation of thermal expansion through their compressible or expandable nature.
Solution Approach 2:
The empty spaces that could potentially facilitate fire propagation are converted into beneficial fire-blocking zones by filling them with fire-resistant materials. These filled spaces actively contribute to safety by creating thermal barriers and oxygen-deprived zones, transforming what was a safety hazard into a protective feature.
3Reliability
If fire-resistant materials are introduced to block flame propagation, then thermal safety is improved, but device complexity increases due to additional components and structural modifications
Solution Approach 1:
Fire-resistant materials are selected and positioned to perform multiple functions simultaneously: blocking flame propagation, providing thermal insulation, filling empty spaces, and accommodating thermal expansion. This multi-functionality reduces the need for separate components for each function, thereby limiting the increase in device complexity while maintaining improved fire safety.
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 design effectively suppresses fires and prevents thermal runaway propagation by filling empty spaces, blocking oxygen entry, and releasing extinguishing materials, enhancing safety in battery modules and packs.
Implementation Method 1
an expansion member located in the module case, and configured to fill at least a part of an empty space in the module case by being expanded in volume when heat is supplied
Data Source
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AI summary
Provided is a battery module or the like with an improved structure to improve safety when a thermal event occurs in the battery module. A battery module according to an aspect of the present disclosure includes a cell assembly including one or more battery cells, a module case having an inner space in which the cell assembly is accommodated, and an expansion member located in the module case, and configured to fill at least a part of an empty space in the module case by being expanded in volume when heat is supplied.