Pouch Battery Sealing Notch for Controlled Gas and Flame Venting
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Solution Overview
Problem
Pouch-type secondary batteries face safety issues due to rapid flame propagation and pressure increase from internal gas generation, particularly at electrode lead protrusions, which can lead to explosions.
Innovation Solution
A pouch-type secondary battery design featuring a sealing part with a notch portion on one side, recessed inward with a curvature, to safely direct gas discharge and delay heat propagation, preventing rapid flame spread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a symmetric sealing part is formed uniformly over the entire edge of the pouch-type casing, then the sealing strength is improved, but the flame propagation speed increases when venting occurs at the lead part
Solution Approach 1:
The sealing part is designed with asymmetric geometry, featuring a first sealing region and a second sealing region with different structures. The second sealing region includes a recessed portion that creates an asymmetric configuration relative to the first sealing region, disrupting symmetric flame propagation patterns and reducing overall flame spread speed.
Solution Approach 2:
Different regions of the sealing part are given different structural qualities. The second sealing region incorporates a recessed portion with specific geometric features that differ from the first sealing region, creating localized structural variations that affect flame propagation characteristics in different areas of the casing.
2Strength
If the pouch-type battery is designed with fixed angular shape, then the electrode assembly is protected from external impact, but the volume reduction capability is limited
Solution Approach 1:
The pouch-type casing is designed with dynamic shape adaptability, allowing the battery to transition between different configurations. The flexible pouch structure enables volume reduction when needed while maintaining protective capabilities, replacing the fixed angular shape with a dynamically adaptable form factor.
Solution Approach 2:
The angular protective structure is replaced with a flexible pouch-type casing that can deform and adapt its shape. This flexible shell structure provides both protection and volume adaptability, allowing the battery to be compressed or reshaped as needed while still protecting the electrode assembly.
3Object-generated harmful factors
If venting occurs at the lead part of the pouch-type battery, then gas discharge is achieved, but the entire battery is rapidly surrounded by flame
Solution Approach 1:
The recessed portion in the second sealing region acts as an intermediary structure that modifies the venting process. It creates a controlled discharge path that separates the direct connection between the interior and exterior at the lead part, thereby reducing the intensity and spread rate of flame during gas discharge events.
Solution Approach 2:
The design converts the potentially harmful direct venting at the lead part into a beneficial controlled discharge mechanism. The recessed portion structure transforms the harmful rapid flame propagation into a controlled gas discharge process that reduces flame spread rate while still achieving necessary pressure relief.
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 notch portion effectively guides gas and flame discharge in a controlled direction, enhancing safety by preventing explosions and reducing the risk of rapid heat propagation.
Implementation Method 1
the pouch-type casing including upper and lower casings thermally bonded to each other
Implementation Method 2
the notch portion has a curvature and is recessed toward the inside of the pouch-type casing... delaying heat propagation
Data Source
AI summary
A secondary battery includes: an electrode assembly; and a pouch-type casing in which the electrode assembly is disposed. The pouch-type casing includes upper and lower casings thermally bonded to each other, in which the pouch-type casing includes a sealing part formed along at least a part of an edge of the pouch-type casing. Electrode leads are connected to the electrode assembly and protrude from sides of the pouch-type casing. The sealing part may include a notch portion formed at an end of any one of the sides from which the electrode leads protrude, and the notch portion may have a curvature that is recessed toward the inside of the pouch-type casing.