Battery Cell Fire-Retardant Assembly for Thermal Runaway Containment
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Solution Overview
Problem
Lithium secondary batteries are prone to thermal runaway, leading to fires and explosions, with flames spreading through empty spaces between battery cells, posing a significant safety risk, especially in electric vehicles.
Innovation Solution
Incorporating a fire-retardant assembly with a fire-retardant material into the empty spaces between battery cells and busbar assemblies to prevent the spread of hot gas and increase thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If empty spaces are left between battery cells for assembly flexibility, then ease of manufacture is improved, but fire spread risk increases due to flame propagation through empty spaces
Solution Approach 1:
A fire-retardant member is introduced as an intermediary substance filled into the empty spaces between battery cells. This member acts as a barrier that prevents flame propagation while maintaining the structural empty space for assembly flexibility. The fire-retardant material (e.g., silicon dioxide) is contained within an exterior material that can melt at a lower temperature to allow flame passage when necessary, creating a smart responsive barrier system.
Solution Approach 2:
The fire-retardant member creates an inert or non-combustible environment within the empty spaces between battery cells. By filling these spaces with fire-retardant material, the patent transforms the empty combustible space into a protected zone that inhibits flame propagation and thermal runaway spread, effectively creating a safety barrier without compromising assembly flexibility.
2Reliability
If fire-retardant material is directly exposed to prevent flame spread, then fire resistance is improved, but hot gas may be discharged toward the tab causing damage
Solution Approach 1:
The exterior material is designed with different properties at different locations and times. It has a lower melting point than the fire-retardant member, allowing it to selectively melt and open pathways for hot gas venting while the fire-retardant member maintains its integrity to block flame propagation. This local differentiation of material properties solves the contradiction between fire resistance and hot gas management.
Solution Approach 2:
The patent converts the potentially harmful effect of hot gas accumulation into a beneficial controlled venting mechanism. The exterior material's lower melting point is intentionally designed to allow controlled melting and hot gas discharge away from the tab, transforming what could be a damaging pressure buildup into a safety release mechanism that protects critical components.
3Reliability
If exterior material melts at lower temperature to vent hot gas, then thermal runaway mitigation is improved, but structural integrity may be compromised
Solution Approach 1:
The fire-retardant assembly is segmented into two distinct functional components: the exterior material and the fire-retardant member. This segmentation allows each component to perform its specific function independently - the exterior material provides structural support and controlled venting, while the fire-retardant member provides flame barrier protection. The segmentation resolves the contradiction by distributing functions across separate elements.
Solution Approach 2:
The patent utilizes parameter changes in material properties, specifically the melting point difference between the exterior material and fire-retardant member. The exterior material is selected with a lower melting point to enable thermal response and controlled venting during thermal runaway, while the fire-retardant member maintains higher temperature resistance for flame blocking. This parameter differentiation allows the system to adapt its behavior based on thermal conditions.
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 fire-retardant assembly effectively contains and mitigates the spread of hot gas, enhancing the safety and stability of battery assemblies by preventing thermal runaway and reducing fire risk.
Implementation Method 1
The exterior material may start to melt when a preset temperature is reached. The temperature may be lower than a melting point of the fire-retardant member.
Data Source
AI summary
Embodiment of the present disclosure relates to a battery assembly including a plurality of battery cells stacked in a preset stacking direction, an accommodation case configured to accommodate the plurality of battery cells, an insertion space formed between the plurality of battery cells and the accommodation case, and a fire-retardant assembly disposed in the insertion space, wherein the fire-retardant assembly includes a fire-retardant member including a fire-retardant material, and a pillar-shaped exterior material configured to accommodate the fire-retardant member therein and extending in a height direction of the accommodation case.