Battery Pack Fireproof Layer for Vent Heat and Flame Isolation
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Solution Overview
Problem
Lithium battery packs are prone to overheating and potential fires or explosions due to thermal runaway events, with existing heat dissipation structures like urethane foam being insufficient to handle high temperatures above 500 °C, risking heat propagation to neighboring cells.
Innovation Solution
A battery pack design incorporating a fireproof fire-extinguishing layer made of fireproof paint, which expands at high temperatures to block air introduction and absorb heat, combined with a thermal-insulating member, effectively preventing heat and flame propagation to nearby cells by forming a carbonized layer and creating a heat dissipation path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If urethane foam potting structure is employed as heat dissipation structure, then heat dissipation is improved, but heat resistance is insufficient at temperatures above 500 °C
Solution Approach 1:
The patent changes the material parameter from conventional urethane foam to fireproof material that can withstand temperatures above 500°C. The fireproof material undergoes parameter transformation by forming a carbonized layer when exposed to high temperature, which maintains structural integrity and provides thermal insulation during fire events, thereby resolving the contradiction between heat dissipation and heat resistance.
Solution Approach 2:
The patent employs a composite structure combining fireproof material with the battery cell assembly. The fireproof material serves as a multi-functional composite that provides both thermal insulation during normal operation and fire resistance during thermal runaway events, achieving both heat dissipation and fire safety requirements simultaneously.
2Temperature
If vent portion is provided for discharging heat and gas, then heat discharge is improved, but fire propagation risk to neighboring cells increases
Solution Approach 1:
The fireproof material acts as an intermediary substance positioned between the vent portion and the surrounding environment. When fire occurs, this intermediary material forms a protective barrier that allows heat and gas to be discharged through the vent while preventing flame propagation to neighboring cells, thus resolving the contradiction between heat discharge effectiveness and fire safety.
Solution Approach 2:
The patent converts the harmful effect of high-temperature gas discharge into a beneficial protective mechanism. The fireproof material is designed to undergo controlled carbonization when exposed to fire, forming a stable carbonized layer that actually protects the battery pack by containing the fire within the vent area and preventing it from spreading to other cells.
3Reliability
If fireproof material is used to block heat propagation, then fire safety is improved, but thermal insulation capability at high temperatures needs enhancement
Solution Approach 1:
The fireproof material utilizes phase transition mechanisms to enhance thermal insulation. When exposed to high temperatures above 500°C, the material undergoes transformation forming a carbonized layer with different thermal properties. This phase transition creates a more effective thermal barrier that maintains fire safety while providing superior thermal insulation capability at elevated temperatures.
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 fireproof fire-extinguishing layer effectively blocks heat propagation and supports the battery cell structure, maintaining thermal insulation and preventing cell collapse, even at temperatures above 1000 °C, thereby reducing the risk of large-scale fires or explosions within the battery pack.
Implementation Method 1
The fireproof fire-extinguishing layer may be configured to foam in (e.g. expand) when exposed to high temperatures to block introduction of air from an ignition point.
Implementation Method 2
a fireproof fire-extinguishing layer between the battery cell and the gas outlet
Data Source
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AI summary
A battery pack includes: a case; a battery cell accommodated at an upper position in the case in a gravity direction; a gas outlet between the battery cell and the case at a lower position of the case and facing a vent portion of the battery cell; and a fireproof fire-extinguishing layer between the battery cell and the gas outlet.