Battery Pack Fire-Fighting Tank for Thermal Runaway Containment
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Solution Overview
Problem
Lithium secondary battery packs face safety challenges due to thermal events, which can lead to ignition or explosion, posing risks to human life and property, especially in densely packed configurations where thermal propagation between cells is not effectively controlled.
Innovation Solution
A battery pack design incorporating a cell module assembly housed in a pack case with a fire-fighting tank located above, storing a fire extinguishing agent that is discharged when heat is applied, using fragile parts that melt to release the agent and prevent thermal runaway between battery cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If battery cells are disposed densely to increase energy density, then energy density is improved, but thermal safety deteriorates due to increased risk of thermal propagation between cells
Solution Approach 1:
A fire-fighting tank containing fire extinguishing agents is introduced as an intermediary component between battery cells. The tank is positioned to receive heat from thermal events and automatically discharge extinguishing agents to suppress thermal propagation, thereby maintaining high energy density while improving thermal safety through the mediating fire suppression system.
Solution Approach 2:
Fire extinguishing agents are pre-stored in the fire-fighting tank before thermal events occur. When heat is applied from battery cells during thermal runaway, the tank automatically discharges the pre-positioned agents to suppress the thermal event, preventing propagation to adjacent cells while maintaining the dense battery configuration.
2Reliability
If fire-fighting tank is added to prevent thermal runaway, then thermal safety is improved, but device complexity increases
Solution Approach 1:
The fire-fighting tank is designed with fragile parts that automatically break when exposed to heat from thermal events. This self-activating mechanism eliminates the need for external sensors, control systems, or power sources, allowing the system to improve thermal safety while adding minimal structural complexity.
Solution Approach 2:
The fragile parts of the fire-fighting tank are designed to undergo phase transition or structural failure at specific temperature thresholds. When heat from thermal runaway reaches the tank, the fragile parts melt or break, triggering automatic discharge of fire extinguishing agents without requiring complex control mechanisms.
3Ease of operation
If fragile parts are designed to melt for agent discharge, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The fragile parts are designed with specific thickness parameters that determine their melting temperature and discharge timing. By controlling the thickness parameter during manufacturing, the system achieves automatic discharge at appropriate temperature thresholds while maintaining ease of operation without requiring complex control systems.
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 controls thermal events within the battery pack, preventing the propagation of thermal runaway and potential ignitions, enhancing safety and manufacturability while maintaining economic efficiency and simplicity in design.
Implementation Method 1
the fire-fighting tank may be configured such that at least a portion thereof is melted by heat applied from the cell module assembly
Data Source
AI summary
A battery pack includes a cell module assembly including a battery cell stack in which a plurality of battery cells are stacked; a pack case configured so as to house the cell module assembly and opened at its upper surface; and a fire-fighting tank located above the cell module assembly and covering the pack case, wherein the fire-fighting tank comprises: an internal space that houses the fire extinguishing agent; and a plurality of fragile parts that are parts where the thickness of the base plate of the fire-fighting tank is relatively thin, and are melted and opened by a thermal event of the battery cell.