Pouch Battery Notch Venting to Redirect Flame From Leads
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Solution Overview
Problem
Pouch-type secondary batteries are prone to rapid flame engulfment due to uncontrolled gas venting at the electrode lead, posing a risk of explosion when internal pressure increases.
Innovation Solution
The secondary battery design incorporates a notch portion in the pouch casing, recessed inward with a curvature, to guide gas and flame venting away from the electrode leads, thereby controlling the direction of venting and delaying heat propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the sealing part is formed uniformly over the entire edge in a symmetric shape, then the battery structure is simple and easy to manufacture, but the entire battery may be rapidly surrounded by flame when internal pressure increases
Solution Approach 1:
The sealing part is designed with an asymmetric configuration where the sealing width varies at different portions. Specifically, the first sealing width at the first edge is different from the second sealing width at the second edge, creating an intentional asymmetric structure that controls venting behavior while maintaining manufacturing simplicity
Solution Approach 2:
Different portions of the sealing part are given different sealing widths to achieve localized control over gas venting. The first portion has a first sealing width and the second portion has a second sealing width, allowing specific areas to vent preferentially while other areas maintain stronger sealing to control flame propagation
2Object-generated harmful factors
If venting occurs at the lead part, then gas can be discharged, but the entire battery is more rapidly surrounded by flame
Solution Approach 1:
The sealing part is designed with different sealing widths at different locations to control where venting occurs. By making the sealing width smaller at specific portions away from the lead part, the design directs gas venting to safer locations while maintaining adequate sealing elsewhere to prevent rapid flame spread to the lead part
3Adaptability or versatility
If the pouch-type battery is designed to be flexible in shape and size, then it is suitable for manufacturing with small thickness and easy assembly, but it lacks the protective structure of angular batteries
Solution Approach 1:
The battery uses a pouch-type flexible casing instead of rigid angular housing. This flexible shell structure allows the battery to be manufactured with small thickness and easily assembled through thermal bonding, while the sealing part design provides controlled protection without requiring rigid external structures
Data Source
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AI summary
A secondary battery according to an embodiment of the present invention includes: an electrode assembly; and a pouch-type casing in which the electrode assembly is embedded, the pouch-type casing including 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 and formed by thermally bonding the upper and lower casings, in which electrode leads connected to the electrode assembly protrude from sides of the pouch-type casing, in which the sealing part includes a notch portion formed at any one end of the side from which the electrode leads protrude, and in which the notch portion has a curvature which is recessed toward the inside of the pouch-type casing.