Cylindrical Battery Venting Structure for Rapid Gas Discharge
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Solution Overview
Problem
Conventional cylindrical sealed batteries face challenges in effectively discharging gases during abnormalities due to the limited area of the gas release opening, which can lead to insufficient gas release and increased risk of thermal runaway and safety hazards.
Innovation Solution
A cylindrical sealed battery design featuring a sealing member with a thin, fragile lid and terminal plate, where the lid is exposed to the outside and forms a large hole upon breakage, allowing rapid gas discharge and preventing clogging by melts, and a holder with a deformation suppressing portion to facilitate breakage and enhance safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the area of the opening in the cap is increased to improve gas discharge efficiency, then gas discharge capability is improved, but the region available for electrical connection is reduced
Solution Approach 1:
The sealing member is divided into functionally independent parts: the lid with fragile portion for gas discharge, the insulating ring for electrical isolation, and the terminal plate for electrical connection. This segmentation allows each component to optimize its specific function without compromising others.
Solution Approach 2:
The gas discharge function is moved from the horizontal plane (cap opening) to the vertical dimension (exposed lid surface), allowing gas to escape upward through the fragile portion of the lid without interfering with the electrical connection area on the cap.
2Productivity
If a conventional cap with opening is used for gas discharge, then gas can be discharged, but the opening area is limited and may be clogged by melts
Solution Approach 1:
The lid is designed with a localized fragile portion that has different mechanical properties (thinner, more brittle) compared to the rest of the lid structure. This local quality change ensures the fragile portion breaks first under pressure to create a large gas discharge opening, while the rest of the lid maintains structural integrity.
Solution Approach 2:
The fragile portion is pre-designed to break at a specific pressure threshold before thermal runaway occurs. This preliminary action of controlled breakage creates a large opening in advance, preventing clogging by melts and ensuring reliable gas discharge when needed.
3Strength
If the lid is fully enclosed for safety, then structural integrity is maintained, but gas cannot be discharged effectively
Solution Approach 1:
The fragile portion is designed to fail in a controlled manner at a predetermined pressure level, preventing the buildup of excessive pressure that would compromise structural integrity. This preliminary failure mode protects the overall structure from catastrophic failure while enabling effective gas discharge.
Solution Approach 2:
The lid with its fragile portion acts as a flexible safety mechanism that can deform and break under excessive pressure, unlike rigid enclosed structures. This thin, fragile design allows the lid to transition from a protective enclosure to a gas discharge pathway when needed.
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 design ensures quicker and more effective gas discharge, reducing the risk of thermal runaway and enhancing safety by preventing sidewall damage and clogging, thereby improving the safety of the battery pack.
Implementation Method 1
the lid having a thin and fragile portion... forms a large hole upon breakage
Implementation Method 2
in the event of pressure increase in the battery... gas generated inside the battery in the event of an abnormality in the battery opens the safety valve and is discharged to the outside
Data Source
AI summary
A nonaqueous electrolyte secondary battery representing an embodiment of a sealed battery of the present invention includes a bottomed cylindrical exterior case, a sealing member, a cylindrical wound electrode assembly and an electrolyte. An open end of the exterior case is crimped together with the sealing member via an insulating gasket so as to form a seal. The sealing member includes a lid having a thin and fragile portion, an insulating ring, and a terminal plate having a thin and fragile portion. The terminal plate is electrically connected to a positive electrode current collector leading out from the cylindrical wound electrode assembly. The lid and the terminal plate are electrically connected within an opening of the insulating ring. The lid is disposed so as to expose an outer side of at least a portion of the lid opposed to the opening of the insulating ring directly to an outside environment.