Grid-Pattern Pouch Sealing for Controlled Battery Venting
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Solution Overview
Problem
Pouch-type lithium secondary batteries are prone to internal pressure buildup due to electrolyte decomposition and gas generation, lacking a vent system, which increases the risk of chain explosions and electrolyte leakage.
Innovation Solution
A grid-like pattern sealing device with alternating convex and concave portions on pressure surfaces induces early venting by creating non-sealing areas that open under increased pressure, combined with temperature control and symmetrical sealing tools to maintain adhesive strength and prevent moisture and oxygen ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing methods are used to completely seal the pouch, then sealing integrity is improved, but the risk of chain explosion increases due to inability to vent internal pressure
Solution Approach 1:
The sealing surface is segmented into multiple convex portions and concave portions, creating a grid-like pattern. The concave portions form non-sealing areas that can open under pressure to allow venting, while the convex portions maintain sealing integrity in other areas. This segmentation resolves the contradiction by dividing the sealing function into selective sealing and selective venting regions.
Solution Approach 2:
Different regions of the sealing surface have different properties: convex portions provide complete sealing with high adhesive strength, while concave portions provide controlled non-sealing areas for pressure relief. This local differentiation allows the pouch to simultaneously maintain sealing integrity and enable safe venting under excessive internal pressure.
2Object-affected harmful factors
If non-sealing areas are created to enable venting, then chain explosion risk is reduced, but adhesive strength and sealing integrity deteriorate
Solution Approach 1:
The sealing surface is divided into discrete convex and concave portions, allowing non-sealing areas to be created without compromising the overall sealing structure. The convex portions maintain strong adhesive bonding, while the concave portions provide controlled openings for venting, thus resolving the contradiction between venting capability and sealing strength.
Solution Approach 2:
Instead of creating large non-sealing areas that would significantly weaken the seal, the invention uses multiple small concave portions distributed across the sealing surface. This partial action approach provides sufficient venting capability through numerous small openings while maintaining overall sealing integrity and adhesive strength through the surrounding convex portions.
3Reliability
If a vent system is added to pouch-type batteries, then safety is improved, but device complexity increases
Solution Approach 1:
The venting function is merged with the sealing structure itself. The concave portions in the sealing surface serve dual purposes: they are integral to the sealing geometry and simultaneously function as pressure relief openings. This merging eliminates the need for separate vent systems, maintaining safety while avoiding additional structural complexity.
Solution Approach 2:
The sealing surface is designed with multi-functionality: it provides sealing integrity through convex portions, enables pressure venting through concave portions, and maintains structural integrity. This universal design allows a single component to perform multiple functions, improving safety without increasing device complexity.
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 device effectively prevents chain explosions and electrolyte leakage by allowing controlled venting, while maintaining sealing integrity and blocking external moisture and oxygen, thus enhancing safety and longevity of pouch-type batteries.
Implementation Method 1
at least one of the first sealing tool and the second sealing tool may include a heating element inside
Implementation Method 2
a first sealing tool including a first pressure surface that is in close contact with a first sheet of the pouch; and a second sealing tool including a second pressure surface that is in close contact with a second sheet of the pouch
Data Source
AI summary
A grid-like pattern sealing device for sealing an electrode assembly by applying pressure to a pouch of a pouch-type battery according to an embodiment includes: a first sealing tool including a first pressure surface that is in close contact with a first sheet of the pouch; and a second sealing tool including a second pressure surface that is in close contact with a second sheet of the pouch, wherein the first pressure surface has a plurality of first convex portions, a plurality of second convex portions, and a plurality of first concave portions formed between the plurality of first convex portions and the plurality of second convex portions, the second pressure surface has a plurality of third convex portions, a plurality of fourth convex portions, and a plurality of second concave portions formed between the plurality of third convex portions and the plurality of fourth convex portions.