Pouch Battery Seal Moisture Adsorbent Barrier
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Solution Overview
Problem
Traditional pouch-type secondary batteries face challenges in achieving a perfect seal, leading to moisture permeation, which damages the batteries, reduces safety, and causes performance degradation and potential explosions due to hydrolysis reactions with fluoride-based electrolytes.
Innovation Solution
Incorporating a moisture adsorbent material, such as an oxazolidine-based compound, calcium chloride, or zeolite, into the inner insulating layer of the pouch packaging, and using a finishing tape with a moisture adsorbent material to prevent moisture permeation through the sealing interfaces and exposed cut surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive polymer such as polypropylene is used in the inner insulating layer to achieve good adhesion by heat fusion, then ease of manufacture is improved, but moisture permeation resistance deteriorates
Solution Approach 1:
The patent applies composite materials by combining polypropylene adhesive polymer with moisture-permeation-resistant materials (such as polyethylene terephthalate or nylon) in the inner insulating layer. This composite structure maintains the adhesion benefits of polypropylene while incorporating materials that resist moisture permeation, thereby resolving the contradiction between ease of manufacture and moisture protection.
Solution Approach 2:
The patent implements local quality by creating regions with different material properties within the inner insulating layer. Specifically, certain areas are designed with enhanced moisture resistance while maintaining overall adhesion capability. This allows the sealing part to achieve both good heat fusion adhesion and localized moisture permeation resistance where most needed.
2Reliability
If the sealing parts are adhered together to seal the internal space, then reliability is improved, but moisture permeation between layers occurs
Solution Approach 1:
The patent uses composite materials in the inner insulating layer comprising both adhesive polymer (polypropylene) and moisture-resistant materials (polyethylene terephthalate or nylon). This composite structure maintains reliable heat fusion adhesion while the moisture-resistant components prevent moisture permeation through the sealed layers, resolving the contradiction between sealability and moisture protection.
Solution Approach 2:
The patent introduces an intermediary moisture-resistant material layer between the adhesive polymer layers. This intermediary layer acts as a barrier to moisture permeation while allowing the adhesive polymer to maintain its sealing function, thereby achieving both reliable adhesion and moisture protection at the sealing interface.
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
Effectively prevents moisture from entering the battery, reducing performance degradation and enhancing safety by maintaining a dry environment within the battery, thus extending its lifespan and preventing potential explosions.
Implementation Method 1
Incorporating a moisture adsorbent material, such as an oxazolidine-based compound, calcium chloride, or zeolite, into the inner insulating layer of the pouch packaging
Data Source
AI summary
The present invention relates to a pouch exterior which can effectively block moisture penetration, and a pouch-type secondary battery comprising the same. In particular, according to the present invention, it is possible to effectively block moisture penetration between bonding interfaces at a sealing part of an upper pouch and a lower pouch. Therefore, according to the present invention it is possible to prevent the deterioration and degradation of performance of a secondary battery due to moisture penetration, and to increase stability of a secondary battery.