Pouch Battery Sealing Structure With Insulation Coating Layers
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Solution Overview
Problem
Pouch type secondary batteries face issues with incomplete sealing due to contamination and dielectric breakdown, leading to moisture permeation and electrolyte leakage, which existing solutions like PET labels and sealing aids fail to adequately address, especially in mass production.
Innovation Solution
A pouch type secondary battery design featuring a bent sealing portion with an insulation coating layer containing heat-dissipating particles and a binder, bonded to both inner and outer surfaces, and a joint portion without heat-dissipating particles, enhancing sealability and heat-dissipation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PET label or tape is used to insulate the outside of the heat-sealing portion, then insulation is improved, but the label and tape may peel off and defects such as air bubbles and wrinkles may occur
Solution Approach 1:
The patent combines the insulation function and sealing function into a single integrated structure. The sealing portion itself is configured to provide insulation by extending outward and covering the heat-sealing portion, eliminating the need for separate PET labels or tapes. This integration resolves the contradiction by achieving both reliable insulation and ease of application in one component.
Solution Approach 2:
The sealing portion is designed to serve multiple functions simultaneously: it provides sealing, insulation, and structural support. By making the sealing portion multi-functional, the patent eliminates the need for additional insulating components that would be difficult to apply, thus resolving the contradiction between insulation reliability and application ease.
2Manufacturing precision
If a sealing aid is applied to the outside of the heat-sealing portion, then sealability is improved, but it is not easy to apply with predetermined viscosity and fluidity on a thin vertical cross section and it flows down during curing
Solution Approach 1:
The patent divides the sealing structure into distinct functional zones: the sealing portion with specific thickness and the insulation portion extending outward. This segmentation allows each zone to be optimized independently - the sealing portion for sealability and the insulation portion for providing a stable surface that prevents sealing aid flow, resolving the contradiction between sealability and application ease.
Solution Approach 2:
The patent extends the sealing portion outward in a direction perpendicular to the main battery body, creating an additional dimensional space. This extension provides a larger surface area for applying sealing aid with controlled viscosity, preventing it from flowing down during curing, thus resolving the contradiction between achieving proper sealability and ease of manufacture.
3Productivity
If the sealing portion is made thin for mass production, then productivity is improved, but it is difficult to apply sealing aid with predetermined viscosity and fluidity
Solution Approach 1:
The patent extends the sealing portion outward to create an insulation portion that provides additional surface area. This dimensional extension allows sealing aid to be applied effectively even when the main sealing portion remains thin for mass production, resolving the contradiction between productivity and ease of sealing aid application.
Solution Approach 2:
The patent applies different properties to different parts of the sealing structure: the main sealing portion remains thin for productivity, while the extended insulation portion provides the necessary surface area and structural support for easy sealing aid application. This local differentiation resolves the contradiction between mass production efficiency and application ease.
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 provides improved sealability, insulation, and heat-dissipation, significantly enhancing the safety and reliability of the battery by maintaining adhesive strength and preventing defects like air bubbles and wrinkles.
Implementation Method 1
an insulation coating layer which is bonded to an inner surface and an outer surface of the bent portion... the insulation coating layer includes a binder and heat-dissipating particles having a thermal conductivity of 0.2 w/(mk) or more
Data Source
AI summary
A pouch type secondary battery includes a pouch type battery case including an electrode assembly housing portion and a sealing portion. An electrode assembly is housed in the housing portion, and an insulation coating layer is laminated on the sealing portion. The insulation coating layer includes a binder and heat-dissipating particles having a thermal conductivity of 0.2 W/(mk) or more.