Pouch Battery Venting Structure for Pressure Relief and Sealability
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Solution Overview
Problem
Pouch-type secondary batteries lack sufficient protection against increased internal pressure due to gas generation, which can lead to component separation, case damage, and potential explosion.
Innovation Solution
A venting device is inserted into the sealing part of the pouch battery, featuring a sheet with a surface treatment layer and a polymer layer, a metal ball, and a plate spring that opens and closes a passage to discharge internal gas when pressure increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a venting device is added to a pouch-type secondary battery to discharge internal gas when pressure increases, then safety and reliability are improved, but device complexity increases
Solution Approach 1:
The venting device is divided into separate functional components: a housing structure, a venting passage with outlet, a plate spring for pressure sensing, and a ball for sealing. This segmentation allows each component to perform its specific function efficiently while keeping the overall design manageable and reliable for preventing battery explosions.
2Object-generated harmful factors
If a venting passage with moving parts (ball and plate spring) is created in the sealing part, then gas discharge capability is improved, but sealability deteriorates
Solution Approach 1:
The ball and plate spring form a self-regulating pressure relief mechanism. When internal pressure exceeds a threshold, the ball is automatically pushed off the outlet by the pressure differential, allowing gas discharge. When pressure normalizes, the plate spring restores the ball to its sealed position. This self-service mechanism maintains sealability under normal conditions while providing automatic gas discharge capability when needed, without requiring external control systems.
3Ease of manufacture
If the plate spring is designed with cap shape and insertion space for the sheet, then ease of manufacture is improved, but device complexity increases
Solution Approach 1:
The plate spring is designed with an integrated cap shape that forms an insertion space directly accommodating the sheet (ball). This merging of the retaining function into the plate spring structure itself eliminates the need for separate retaining components, simplifying the assembly process and reducing part count while maintaining the necessary mechanical functionality for pressure sensing and ball retention.
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 venting device effectively adjusts internal pressure by discharging excess gas, improving sealability and preventing damage to the battery case, while ensuring reliable operation and safety.
Implementation Method 1
a plate spring (153) formed to surround the ball (155) and the sheet (152) and having elasticity to open and close the passage (154) together with the ball (155) according to an internal pressure of the pouch
Implementation Method 2
a sheet (152) which is made of a metal and formed in the housing (151) and through which a passage (154) passes, and a surface treatment layer (1522) formed on one surface (1521) of the sheet (152)
Data Source
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AI summary
To solve the above problem, a venting device inserted into a sealing part of a pouch of a secondary battery according to the present invention includes: a housing inserted between both surfaces of the sealing part and sealed together with the sealing part; a sheet which made of a metal and formed in the housing and through which a passage allowing the inside and outside of the pouch to communicate with each other passes; and a ball contacting or spaced apart from the sheet at an outlet-side of the passage to open and close the passage, wherein, in the sheet, an edge of an inner circumference of a surface of the outlet-side of the passage is chamfered or filleted so as to face the ball, and the sheet includes: a surface treatment layer formed on the chamfered or filleted one surface; and a polymer layer made of a polymer and fused to the surface treatment layer.