Battery Cap Assembly Venting Through an Exposed Safety Notch
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Solution Overview
Problem
Secondary batteries face safety concerns due to the inability to easily discharge internal gas, which can lead to pressure buildup and potential explosions.
Innovation Solution
A secondary battery design featuring a cap assembly with a safety vent that includes a notch exposed through an opening, allowing rapid venting of internal gas, comprising a cap-up, a safety vent, and a cap-down with a gas vent hole, and a gasket for secure assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional cap assembly without an exposed notch is used, then the structural integrity and sealing are maintained, but internal gas cannot be easily discharged leading to pressure buildup and safety risks
Solution Approach 1:
The cap-up is divided into functional zones: a sealing portion that contacts the case, a terminal portion for electrical connection, and a connecting portion with an opening that exposes the notch. This segmentation allows the same component to provide both sealing integrity and gas discharge functionality without requiring additional parts.
Solution Approach 2:
The safety vent mechanism is integrated directly into the cap-up structure by forming the notch within the cap-up material itself and exposing it through the opening. This merging eliminates the need for separate safety vent components while maintaining both structural integrity and gas discharge capability.
2Speed
If a safety vent with a covered notch is used, then structural integrity is maintained, but gas venting speed is insufficient to prevent pressure buildup
Solution Approach 1:
The notch is extracted from the interior of the cap-up and exposed to the exterior environment through the opening in the connecting portion. This extraction allows gas to escape directly from the battery interior through the notch without being blocked by cap-up material, dramatically increasing venting speed while the notch geometry maintains pressure control.
3Productivity
If the opening area is small, then the cap-up maintains structural strength, but gas discharge capability is insufficient
Solution Approach 1:
The opening is positioned in the connecting portion where the cap-up transitions between the terminal and sealing portions. This location provides optimal local quality characteristics: sufficient structural support from the adjacent terminal and sealing portions, while the opening itself allows high-rate gas discharge. The notch geometry further optimizes this by providing a controlled escape path.
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 effectively vents internal gas, enhancing safety by preventing pressure buildup and reducing the risk of explosions, as demonstrated by thermal diffusion tests showing improved safety with a notch area proportion of 55% or more.
Implementation Method 1
a safety vent provided under the cap-up and having a notch to be ruptured at a predetermined pressure or higher
Data Source
AI summary
The present invention relates to a secondary battery which can easily vent internal gas, thereby enhancing safety. Disclosed as an example is a secondary battery comprising: an electrode assembly; a case in which the electrode assembly is accommodated; and a cap assembly which is coupled to the top of the case and comprises a cap-up having opening, a safety vent provided under the cap-up and having a notch to be ruptured at a predetermined pressure or higher, and a cap-down provided under the safety vent and electrically connected to the electrode assembly, wherein the notch is exposed through the opening.