Sealed Battery Sealing Assembly with Inverting Vent
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Solution Overview
Problem
Existing sealed batteries face challenges in securely disconnecting the current path during abnormal conditions, such as overpressure, which can lead to safety issues and potential reconnection of the current path.
Innovation Solution
A sealed battery design featuring a sealing assembly with a metal plate having a thin, annular shape and a vent part that inverts outward when internal pressure exceeds a predetermined threshold, accompanied by an elastic deformation gasket that assists the vent part in separating from the annular part, ensuring secure disconnection of the current path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing assembly with a metal plate is used to seal the battery opening, then the battery can be sealed effectively, but the current path may not be securely disconnected upon abnormality occurrence
Solution Approach 1:
The metal plate is segmented into functionally distinct regions: a vent part with downward convexity that inverts under pressure, a thin part that fractures to disconnect current, and an annular part for electrical connection. This segmentation allows each region to perform its specific function optimally while contributing to secure current path disconnection during abnormalities.
Solution Approach 2:
The vent part is designed with specific geometric parameters (downward convexity, thin part thickness, area ratios) that change its mechanical behavior under pressure. When internal pressure reaches a threshold, these parameter changes cause the vent part to invert and the thin part to fracture, reliably disconnecting the current path.
2Reliability
If the vent part inverts outward when internal pressure exceeds threshold, then the current path can be disconnected, but the disconnection state may not be maintained securely with potential reconnection
Solution Approach 1:
The thin part is pre-designed with reduced thickness and specific geometry to ensure it fractures at a controlled location before the welding portions can be compromised by reverse inversion. This preliminary design ensures that current disconnection occurs first, preventing any potential reconnection even if the vent part later inverts back.
Solution Approach 2:
Different regions of the metal plate have different local qualities: the thin part has reduced thickness for easy fracture, while the welding portions have sufficient strength for secure connection during normal operation. This local quality differentiation ensures that fracture occurs only where intended, maintaining reliable disconnection.
3Reliability
If an elastic deformation part is added to the gasket to assist vent part separation, then current path disconnection is enhanced, but the device complexity increases
Solution Approach 1:
An elastic deformation part is introduced as an intermediary between the vent part and the gasket body. This elastic component assists the vent part in separating from the annular part during inversion by providing additional elastic force, thereby enhancing current path disconnection security while maintaining a relatively simple overall structure.
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 and securely disconnects the current path during abnormal conditions and inhibits reconnection, enhancing safety by maintaining the disconnection state.
Implementation Method 1
An elastic deformation part that comes into contact with an inner surface of the vent part and urges the vent part toward the outside of the battery case is provided in the gasket
Data Source
Figure 1
Figure 2~3
Figure 4(a)~4(b)
AI summary
The purpose of the present disclosure is to more reliably interrupt the current path of a battery when an abnormality occurs in the battery and the internal pressure of the battery case rises. A sealed battery, which is an exemplary embodiment, comprises a battery case including a bottomed cylindrical outer can and a sealing body that closes an opening of the outer can, a gasket disposed between the outer can and the sealing body, and an electrode body including an electrode and housed in the battery case. The sealing body includes a metal plate, and the metal plate has a thin portion formed in an annular shape, a valve portion having a convex shape inside the battery case, and an annular portion to which the electrode lead is connected. The gasket is provided with an elastically deformable portion that abuts against the inner surface of the valve portion and urges the valve portion to the outside of the battery case.