Pouch Battery Case Venting With Hydrophobic Gas Discharge Layer
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Solution Overview
Problem
Pouch type secondary batteries lack effective mechanisms to discharge internal gas and adjust pressure when internal pressure increases, leading to potential damage and safety risks such as deformation, short-circuit, and explosion.
Innovation Solution
A battery case with a gas discharge part that includes a gas discharge layer and an outer functional layer with hydrophobic properties, allowing gas to escape while preventing moisture and electrolyte leakage, and a coating part to protect the metal barrier layer from corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a pouch type secondary battery is used to achieve flexibility and miniaturization, then the battery can be applied to small-sized products and portable devices, but the battery lacks sufficient protection members to discharge internal gas when pressure increases, leading to safety risks
Solution Approach 1:
The battery case is segmented into multiple functional layers: a cup part for accommodation, a sealing part for closure, and a gas discharge part with layered structure (gas discharge layer and outer functional layer) for selective gas release. This segmentation allows each part to perform its specific function while maintaining overall battery safety and flexibility.
Solution Approach 2:
The gas discharge part acts as an intermediary mechanism between the internal battery environment and external atmosphere. It selectively allows gas to pass through while blocking electrolyte and moisture, serving as a mediator that resolves the conflict between pressure relief and sealing requirements.
2Reliability
If protection members such as CID filter and safety vent are provided in can type secondary battery to prevent pressure-related damage, then explosion and short-circuit risks are reduced, but the structure becomes more complex and less suitable for miniaturized applications
Solution Approach 1:
The gas discharge part integrates multiple functions into a single component: gas discharge, electrolyte blocking, and moisture prevention are combined in one layered structure attached to the battery case. This merging reduces the number of separate protection members needed while maintaining comprehensive safety functionality.
Solution Approach 2:
The gas discharge part uses thin film structures with hydrophobic properties that provide effective protection while maintaining flexibility and minimizing added complexity. The thin film approach allows the protection mechanism to be integrated into the pouch structure without significant bulk or rigidity.
3Reliability
If a gas discharge part with hydrophobic outer functional layer is attached to the battery case to selectively discharge gas while preventing electrolyte leakage, then safety is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The gas discharge part with its hydrophobic outer functional layer is prepared in advance as a pre-assembled unit before attachment to the battery case. This preliminary preparation allows the complex layered structure to be manufactured and tested separately, simplifying the final assembly process and reducing manufacturing complexity.
Solution Approach 2:
The hydrophobic outer functional layer provides self-selective functionality based on the physical properties of different substances (gas versus electrolyte). The material inherently distinguishes between gas molecules and liquid electrolyte, allowing selective discharge without complex mechanical valves or control mechanisms.
4Ease of manufacture
If the battery case structure is simplified to improve ease of manufacture, then production efficiency increases, but the ability to discharge internal gas and adjust pressure is compromised
Solution Approach 1:
The gas discharge part serves multiple functions simultaneously: it acts as a pressure relief valve, an electrolyte barrier, and a moisture prevention layer. This multi-functionality allows a single added component to provide comprehensive pressure management without significantly complicating the overall structure or manufacturing process.
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 internal gas to adjust pressure, prevents moisture and electrolyte leakage, and enhances user convenience by simplifying the structure and improving durability.
Implementation Method 1
an outer functional layer formed on an outer surface of the gas discharge layer and having a hydrophobic property
Implementation Method 2
a gas discharge layer through which the gas passes
Implementation Method 3
a coating part applied to an inner circumferential surface of the hole and having electrolyte resistance
Data Source
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AI summary
A battery case for a secondary battery according to an embodiment of the present invention for solving the above problems includes: 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; a gas discharge part attached to a hole which is formed to be punched in at least one of the cup part or the sealing part from the outside and through which a gas passes; and a coating part applied to an inner circumferential surface of the hole and having electrolyte resistance, wherein the gas discharge part includes: a gas discharge layer through which the gas passes; and an outer functional layer formed on an outer surface of the gas discharge layer and having a hydrophobic property.