Thin Battery Resin Heat-Sealing for Leakage Prevention
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Solution Overview
Problem
Existing thin-type batteries using laminate films for exterior bodies face issues with incomplete heat-sealing due to resilience, leading to potential liquid leakage and damage to the aluminum laminate sheet.
Innovation Solution
Incorporating resin-interposed heat-sealing portions made from hot-melt synthetic resin, such as polypropylene, to ensure hermetic sealing of the folded regions in the laminate film exterior body, reducing the need for excessive force and minimizing the risk of leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the aluminum laminate sheet is folded with greater force to overcome resilience, then the heat-sealing completeness is improved, but the aluminum element may be damaged causing electrolytic solution leakage
Solution Approach 1:
A resin layer is introduced as an intermediary material between the folded portions of the aluminum laminate sheet. This resin layer acts as a mediator that fills the gap caused by sheet resilience, enabling effective heat-sealing without requiring excessive folding force that would damage the aluminum elements.
Solution Approach 2:
The exterior body is constructed as a composite structure combining the aluminum laminate sheet with a resin layer. This composite material approach allows the resin to compensate for the aluminum sheet's resilience, achieving both complete heat-sealing and protection of the aluminum elements from damage.
2Shape
If the aluminum laminate sheet is folded to create the tubular body, then the exterior body shape is formed, but a gap between folded portions spreads due to resilience preventing full heat-sealing
Solution Approach 1:
The resin layer serves as a filler material that occupies the gap between folded portions of the aluminum laminate sheet. This intermediary substance allows the folded structure to maintain its shape while eliminating the spacing that would prevent complete heat-sealing contact.
Solution Approach 2:
By combining the aluminum laminate sheet with the resin layer to form a composite exterior body, the structure achieves both the required tubular shape and the dimensional precision needed for effective heat-sealing, as the resin compensates for the aluminum's elastic deformation.
3Manufacturing precision
If excessive force is applied to fold the aluminum laminate sheet, then the heat-sealing gap is reduced, but the aluminum element is damaged potentially causing electrolytic solution leakage
Solution Approach 1:
The resin layer acts as a space-filling intermediary that allows precise control of the heat-sealing gap without requiring high folding forces. The resin material itself fills any remaining gaps, enabling accurate sealing while protecting the aluminum elements from mechanical damage.
Solution Approach 2:
The composite structure of aluminum laminate sheet combined with resin layer provides both the mechanical strength needed for folding and the gap-filling capability for precise heat-sealing, eliminating the need to apply excessive force that would compromise aluminum element integrity.
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 solution effectively prevents liquid leakage and maintains the integrity of the laminate film, allowing for a more reliable hermetic seal and increased energy density by reducing the heat-sealing area, thus enhancing the battery's performance and capacity.
Implementation Method 1
heat-sealing portions located in regions in two ends in a direction along the edge of the electrode body and outside the electrode body where portions of the exterior body are opposed to each other. Each resin-interposed heat-sealing portion being heat-sealed by interposing a heat-sealing piece made from a hot-melt synthetic resin.
Data Source
AI summary
A thin-type battery includes: a flat shaped electrode body formed by stacking a positive electrode and a negative electrode while interposing a separator in between; an electrolyte; and an exterior body made from a laminate film, the exterior body enclosing the electrode body and the electrolyte with ends of the exterior body being hermetically sealed by heat-sealing, wherein the exterior body includes a folded part to be folded from one surface side to another surface side of the electrode body and to extend along an edge of the electrode body, and the folded part includes resin-interposed heat-sealing portions located in regions in two ends in a direction along the edge of the electrode body and outside the electrode body, where portions of the exterior body are opposed to each other, each resin-interposed heat-sealing portion being heat-sealed by interposing a piece made from a resin.