Pouch Battery Venting Structure With Ball-Sealed Pressure Relief
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Solution Overview
Problem
Pouch-type secondary batteries lack effective pressure regulation mechanisms, leading to potential damage and safety issues due to internal gas buildup, as they do not have sufficient protection members to manage increased internal pressure.
Innovation Solution
A venting device is inserted into the sealing part of the pouch battery, comprising a metal sheet with a chamfered passage, a surface treatment layer, a polymer layer, and a plate spring, which opens to discharge excess gas when internal pressure exceeds a certain threshold, ensuring safe pressure adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a venting device with metal sheet and polymer layer is used, then the sealability and safety are improved, but the device complexity increases
Solution Approach 1:
The venting device uses a composite structure consisting of a metal sheet with a passage, a surface treatment layer on the metal sheet, and a polymer layer fused to the surface treatment layer. This composite material approach provides both mechanical strength from the metal and sealing properties from the polymer, resolving the contradiction between safety and device complexity by integrating multiple functions into a single composite component.
Solution Approach 2:
The venting device is segmented into distinct functional layers: the metal sheet provides structural support and defines the passage geometry, the surface treatment layer enhances adhesion and corrosion resistance, and the polymer layer provides sealing. This segmentation allows each layer to be optimized independently while working together to achieve safe and effective pressure relief.
2Reliability
If the passage edge is chamfered or filleted with surface treatment and polymer layer, then the ball contact and sealing are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The passage edge is constructed as a composite structure with the metal sheet base, surface treatment layer for adhesion enhancement, and polymer layer for sealing. This composite approach compensates for minor dimensional variations in the metal sheet by providing compliant sealing layers, thereby improving sealability without requiring extremely tight manufacturing tolerances on the base metal component.
Solution Approach 2:
The chamfer or fillet geometry at the passage edge is optimized to work with the polymer layer, creating a tapered or rounded contact surface that facilitates ball seating and sealing. This geometric parameter optimization, combined with the polymer layer's compliance, achieves reliable sealing while accommodating reasonable manufacturing tolerances.
3Adaptability or versatility
If a plate spring is added to open and close the passage, then the pressure regulation capability is improved, but the device complexity increases
Solution Approach 1:
The plate spring introduces dynamic functionality to the venting device, allowing the passage to automatically open when internal pressure exceeds a threshold and close when pressure returns to normal levels. This dynamic pressure regulation capability is achieved through the elastic deformation of the plate spring, which mechanically responds to pressure changes without requiring external control systems.
Solution Approach 2:
The plate spring enables the venting device to self-regulate pressure through its elastic properties. When pressure builds up, the spring deflects to open the passage; when pressure normalizes, the spring returns to its original position, closing the passage. This self-service mechanism provides adaptive pressure control without external intervention, improving pressure regulation capability while adding only a single spring component.
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 regulates internal pressure by discharging excess gas, enhancing the sealability and safety of pouch-type secondary batteries by preventing damage and potential explosions.
Implementation Method 1
a polymer layer made of a polymer and fused to the surface treatment layer
Implementation Method 2
a plate spring formed to surround the ball and the sheet and having elasticity to open and close the passage together with the ball according to an internal pressure of the pouch
Implementation Method 3
an edge of an inner circumference of a surface of the outlet-side of the passage is chamfered or filleted, and the sheet includes: a surface treatment layer formed on the chamfered or filleted one surface to face the ball
Data Source
Figure 1
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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.