Pouch Battery Case Venting Structure for Internal Gas Pressure Relief
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Solution Overview
Problem
Pouch type secondary batteries lack sufficient protection mechanisms to manage increased internal pressure due to gas generation, which can lead to component damage, early activation of protection circuits, deformation, internal short-circuits, and potential explosions.
Innovation Solution
A battery case with a gas discharge part that includes a melted layer of thermoplastic resin and a thermosetting layer, attached to a hole in the case, allowing gases to escape and adjust internal pressure. The gas discharge part is designed to prevent external moisture ingress and fusion with the sealing block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas discharge part is added to the pouch type secondary battery, then the ability to discharge inner gas and adjust pressure is improved, but the device complexity increases
Solution Approach 1:
The gas discharge part is divided into two distinct layers: a melted layer made of thermoplastic resin and a thermosetting layer made of thermosetting resin. This segmentation allows each layer to perform its specific function - the melted layer provides gas permeability when heated, while the thermosetting layer maintains structural integrity and prevents fusion with the sealing block.
Solution Approach 2:
The gas discharge part uses a composite structure combining thermoplastic resin and thermosetting resin layers. This composite material approach enables the simultaneous achievement of gas discharge functionality (through the thermoplastic layer's melting and permeability) and structural stability (through the thermosetting layer's heat resistance and non-fusion properties).
2Ease of operation
If the gas discharge part is made entirely of thermoplastic resin, then gas discharge functionality is improved, but the risk of fusion with sealing block during thermal processing increases
Solution Approach 1:
The thermosetting layer is placed on the outer surface of the thermoplastic resin layer before thermal processing occurs. This layer acts as a protective barrier that prevents the thermoplastic resin from directly contacting and fusing with the sealing block during subsequent heating operations, thus cushioning against the harmful effect of fusion.
Solution Approach 2:
The thermosetting layer serves as an intermediary between the thermoplastic resin layer and the sealing block. It allows the thermoplastic layer to perform its gas discharge function while being heated, but prevents direct thermal contact and fusion with the sealing block, thus mediating the thermal interaction.
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 discharges inner gases to the outside when internal pressure increases, preventing damage to the battery components and maintaining the integrity of the sealing mechanism, while also preventing the gas discharge part from being melted and fused to the sealing block.
Implementation Method 1
a melted layer including a thermoplastic resin that is melted when heat is applied; and a thermosetting layer laminated on one surface of the melted layer and including a thermosetting resin that is not melted by heat
Data Source
AI summary
A battery case for a secondary battery according to an embodiment of the present invention can include a cup part having an accommodation space configured to accommodate an electrode assembly in which electrodes and separators are stacked, a sealing part extending to the outside of the cup part, and a gas discharge part which is attached to a hole formed to be punched in at least one of the cup part or the sealing part and through which a gas passes. The gas discharge part can include a melted layer comprising a thermoplastic resin that is melted when heat is applied, and a thermosetting layer laminated on one surface of the melted layer and comprising a thermosetting resin that is not melted by heat.