Three-Layer Battery Vent Member for Sealed Thermal Gas Release
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Solution Overview
Problem
Conventional secondary batteries face challenges in safely discharging gases generated during thermal propagation, leading to potential fires due to inadequate directional venting capabilities.
Innovation Solution
A secondary battery design incorporating a vent member with a three-layer structure, comprising a first resin with a lower melting point, a second resin with a higher melting point, and a third resin with an even higher melting point, strategically positioned to facilitate directional gas discharge while maintaining sealing properties during normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sealing structure is used to maintain battery integrity, then sealing property is improved, but directional gas discharge capability deteriorates
Solution Approach 1:
The vent member is divided into three distinct layers (first resin layer, second resin layer, third resin layer) with different melting points. This segmentation allows each layer to perform a specific function: the first layer seals at normal temperatures, while the second and third layers provide directional venting pathways at elevated temperatures, thus resolving the contradiction between maintaining sealing and enabling gas discharge.
Solution Approach 2:
The invention utilizes parameter changes in the form of temperature-dependent melting behavior of different resin layers. The vent member transitions from a sealed state (all layers solid) to a venting state (second and third layers melt) as temperature increases, allowing the same structure to provide both sealing and directional gas discharge capabilities under different operating conditions.
2Object-generated harmful factors
If a vent member with low melting point resin is used to enable gas discharge, then gas discharge capability is improved, but sealing property at elevated temperatures deteriorates
Solution Approach 1:
The vent member is divided into three distinct layers (first resin layer, second resin layer, third resin layer) with different melting points. This segmentation allows each layer to perform a specific function: the first layer seals at normal temperatures, while the second and third layers provide directional venting pathways at elevated temperatures, thus resolving the contradiction between maintaining sealing and enabling gas discharge.
Solution Approach 2:
The vent member is constructed as a composite structure combining three different resin materials with progressively higher melting points. This composite design enables the vent member to exhibit both sealing behavior (at temperatures below the second resin's melting point) and directional venting behavior (at temperatures above the second resin's melting point), resolving the contradiction between sealing and gas discharge requirements.
3Device complexity
If a single-layer vent member is used to simplify structure, then device complexity is reduced, but directional venting capability deteriorates
Solution Approach 1:
The vent member is divided into three distinct layers (first resin layer, second resin layer, third resin layer) with different melting points. This segmentation allows each layer to perform a specific function: the first layer seals at normal temperatures, while the second and third layers provide directional venting pathways at elevated temperatures, thus resolving the contradiction between maintaining sealing and enabling gas discharge.
Solution Approach 2:
Different regions of the vent member (different layers) are赋予 different properties: the first resin layer has a lower melting point for sealing, while the second and third resin layers have higher melting points to maintain structural integrity and provide directional venting. This local differentiation of material properties enables the vent member to achieve both simplicity and effective directional gas discharge.
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 enhances safety by ensuring directional gas discharge during abnormal conditions, improving the rigidity of the vent member to prevent early venting and maintain sealing integrity at elevated temperatures.
Implementation Method 1
a vent member inserted into the vent region and having a structure of three or more layers including a first resin in a lowermost layer, a second resin in an uppermost layer, and a third resin in a middle layer, wherein the second resin is a resin having a higher melting point than the first resin, and the third resin is a resin having a higher melting point than the second resin
Data Source
AI summary
Disclosed herein is a secondary battery. The secondary battery can include an electrode assembly, an electrode lead attached to the electrode assembly, a case configured to accommodate the electrode assembly, a lead film formed to surround a part of an outer surface of the electrode lead and interposed between the electrode lead and the case, a vent region formed in at least a part of the case, and a vent member inserted into the vent region and having a structure of three or more layers including a first resin in a lowermost layer, a second resin in an uppermost layer, and a third resin in a middle layer. The second resin can be a resin having a higher melting point than the first resin, and the third resin can be a resin having a higher melting point than the second resin.