Pouch Cell Sealing Rollers for Low-Pressure Venting
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Solution Overview
Problem
Pouch-shaped battery cells lack effective venting mechanisms, leading to potential swelling and explosion due to increased internal pressure, especially when the sealing pressure is non-uniform and venting is difficult.
Innovation Solution
A pair of sealing rollers that press and roll the sealed portion of a pouch-shaped battery cell, with each roller rotating in opposite directions to melt and move the inner adhesive layer outward, forming a larger outer polyball to facilitate venting and reduce internal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the inner adhesive layer is melted and pushed inward to form a large inner polyball during sealing, then the sealing strength is improved, but the venting capability deteriorates because the large inner polyball blocks gas discharge paths
Solution Approach 1:
The patent applies different qualities to different regions of the adhesive layer. The adhesive layer is configured with varying thickness or composition: thicker or higher melting point adhesive near the sealed portion to maintain sealing strength, and thinner or lower melting point adhesive near the outer periphery to facilitate venting. This local differentiation allows the sealed portion to have strong sealing while the outer periphery provides effective venting paths.
Solution Approach 2:
Instead of forming a large inner polyball that blocks venting, the patent inverts the approach by controlling the adhesive layer to form a smaller inner polyball and directing more adhesive material outward to form a larger outer polyball. This inversion of the polyball size relationship (inner polyball smaller than outer polyball) reverses the harmful effect and creates effective venting channels through the outer polyball structure.
2Device complexity
If the sealing pressure is applied uniformly across the entire sealed portion, then the sealing process is simple, but the venting capability deteriorates due to non-uniform pressure distribution and gas concentration at specific points
Solution Approach 1:
The patent segments the sealing process into distinct zones: a sealed portion where strong sealing is required and an outer periphery region where venting is prioritized. By dividing the sealing area into these functional segments with different adhesive layer characteristics, the patent achieves both effective sealing and effective venting without requiring complex multi-stage sealing equipment.
Solution Approach 2:
The patent implements local quality by creating spatial variation in the adhesive layer properties across the sealed portion. The adhesive layer has different thickness, composition, or melting characteristics at different locations: stronger adhesive properties near the sealed portion for sealing integrity, and weaker or thinner adhesive properties at the outer periphery for easy venting. This local differentiation resolves the contradiction between uniform sealing and localized venting needs.
3Device complexity
If the pouch-shaped battery cell includes no separate venting structure to simplify design, then the device complexity is reduced, but the reliability deteriorates because venting can only occur at weak points leading to uncontrolled swelling
Solution Approach 1:
The patent makes the adhesive layer multi-functional: it serves both as a sealing material to bond the laminate sheets together and as a venting mechanism through its controlled melting and polyball formation. By integrating the venting function into the existing adhesive layer rather than adding a separate venting structure, the patent achieves reliable pressure control while maintaining simple device design.
Solution Approach 2:
The adhesive layer performs self-service by automatically providing venting functionality through its inherent melting and flow characteristics when exposed to internal pressure. The controlled formation of the outer polyball creates self-opening venting paths without requiring external activation or additional components. The system uses its own material properties (adhesive melting behavior) to provide the safety function.
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 allows for rapid venting even at low pressure, preventing swelling and explosion by ensuring the outer polyball is larger than the inner polyball, thus enhancing safety.
Implementation Method 1
an outer periphery of the pouch-shaped battery case is pressed using a heating block configured to provide heat and pressure. As a result, the inner adhesive layer is melted, whereby inner adhesive layers of an upper case and a lower case, which are stacked on top of each other, are thermally fused to form a seal.
Implementation Method 2
the inner adhesive layer is melted, whereby inner adhesive layers of an upper case and a lower case, which are stacked on top of each other, are thermally fused to form a seal.
Implementation Method 3
an outer periphery of the pouch-shaped battery case is pressed using a heating block configured to provide heat and pressure.
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a pouch-shaped battery cell sealing apparatus including a pair of sealing rollers configured to press and roll an upper part and a lower part of a sealed portion of a pouch-shaped battery cell, respectively, wherein the pair of sealing rollers includes a first sealing roller and a second sealing roller, and the pair of sealing rollers are configured to seal the sealed portion while moving in a direction from an inside to an outside of the sealed portion, a sealing method using the same, and a pouch-shaped battery cell manufactured using the same. The pouch-shaped battery cell may be easily vented under low internal pressure.