Pouch Battery Seal Indentations Prevent Resin Leakage
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Solution Overview
Problem
Pouch-type secondary batteries face issues with resin layers seeping out during sealing, leading to reduced seal reliability and potential short circuits due to the soft nature of the pouches, which limits their use with lithium ion batteries using liquid electrolytes.
Innovation Solution
The introduction of indentations on the lip and cover of the pouch, which fill with thermal adhesive resin during sealing, prevents resin layers from escaping and creates adhesive cores for a stronger seal, and the use of a sealing apparatus with pressure and heat application to ensure the resin stays within the pouch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the sealing area of the pouch is reduced to increase battery capacity, then the battery capacity increases, but the seal reliability decreases
Solution Approach 1:
The patent applies local quality by creating indentations specifically at the sealing area of the pouch while maintaining other structural properties. These localized structural modifications concentrate the adhesive resin at critical sealing points, enhancing seal reliability precisely where needed without requiring an increased overall sealing area, thus allowing battery capacity to increase while maintaining seal integrity.
Solution Approach 2:
The patent employs composite materials by combining the pouch structure with thermal adhesive layers that contain resin. The indentation structure works in conjunction with this composite material system, where the resin fills the indentations during sealing to create a reinforced seal. This composite approach allows the seal to achieve high reliability with reduced sealing area through the synergistic effect of the indentation structure and adhesive material.
2Ease of manufacture
If thermal adhesive layers are used to seal the pouch, then the sealing process is simplified, but the resin layers seep out during sealing reducing seal reliability
Solution Approach 1:
The patent converts the harmful effect of resin seeping out during sealing into a beneficial outcome. By providing indentations in the sealing area, the resin that would otherwise leak out is redirected to fill these indentations. This transforms the harmful resin flow into a useful adhesive core formation process, enhancing seal reliability while maintaining the simplicity of the thermal adhesive sealing process.
Solution Approach 2:
The patent applies preliminary anti-action by pre-forming indentations in the pouch structure before the sealing process. These indentations are strategically positioned to counteract the natural tendency of resin to seep out during sealing. The pre-existing structural features guide the resin flow in advance, preventing the harmful effect before it occurs and ensuring the resin remains contained within the sealing area.
3Adaptability or versatility
If the pouch structure is made softer to improve flexibility, then the adaptability increases, but the seal reliability decreases
Solution Approach 1:
The patent applies local quality by creating specific structural features (indentations) at the sealing area while maintaining the overall soft and flexible nature of the pouch. The indentation structure provides localized reinforcement precisely where seal reliability is needed, without compromising the global flexibility and adaptability of the pouch body. This allows the pouch to remain adaptable for various battery configurations while achieving reliable sealing at critical points.
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
This solution enhances the reliability of the pouch seal, prevents short circuits, and allows for increased battery capacity while maintaining a reduced sealing area, making pouch-type batteries more suitable for lithium ion batteries with liquid electrolytes.
Implementation Method 1
During thermal fusion of the thermal adhesive polyolefin layer of the cover (10) to the thermal adhesive polyolefin layer of the container (20)
Implementation Method 2
an aluminum metal layer 13 that serves as a material for maintaining mechanical strength, a water and oxygen barrier layer, a nylon layer 11, and a protective layer. The pouch is formed by sequentially laminating these layers. Cast polypropylene (CPP) is commonly used as the polyolefin layer.
Implementation Method 3
indentations formed on the lip and cover of the pouch, which fill with thermal adhesive resin during sealing
Data Source
AI summary
A pouch for a secondary battery comprising indentations on a sealing area of the pouch is disclosed. At least some of the indentations are filled with the resin layers of the pouch. A secondary battery comprising the pouch, and an apparatus for sealing the pouch are also provided. The indentations in the pouch can take the shape of dots or lines, and prevent the resin layers of the pouch from leaking out of the pouch during heating and pressing of the sealing area of the pouch. Also, when the resin layers collect in the indentations, forming adhesive cores, reliability of the pouch seal is improved despite a reduction in the sealing area of the pouch.