Secondary Battery Vent Member for Lead-Side Gas Release Control
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Solution Overview
Problem
Conventional secondary batteries face challenges in directing gas discharge during thermal propagation, which can lead to increased fire risk due to uncontrolled gas release.
Innovation Solution
A secondary battery design incorporating a vent member with a vent resin having a lower melting point than the sealant resin, positioned to facilitate controlled gas discharge in a specific direction, minimizing direct contact with electrode leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wound type diaphragm is used to accommodate volume changes of the battery, then the battery can expand and contract, but the diaphragm may be damaged due to repeated expansion and contraction
Solution Approach 1:
The diaphragm is divided into a fixed portion and a movable portion that can slide relative to each other. The movable portion accommodates volume changes through linear displacement rather than elastic deformation, reducing stress concentration and preventing damage from repeated expansion and contraction cycles.
Solution Approach 2:
Instead of using an elastic diaphragm that expands and contracts, the invention uses an inelastic movable portion that slides linearly. This inverts the traditional approach by using rigid components with relative motion rather than flexible components with elastic deformation, thereby improving durability.
2Adaptability or versatility
If the battery case is divided into multiple cases to accommodate volume changes, then the battery can expand and contract, but the number of parts increases making the structure complicated
Solution Approach 1:
The fixed and movable portions are integrated into a single battery case structure that works together with the diaphragm assembly. This merging reduces the number of separate components compared to using multiple independent battery cases, simplifying the overall structure while still accommodating volume changes.
Solution Approach 2:
Volume accommodation is achieved through linear displacement of the movable portion in one dimension rather than requiring multiple three-dimensional cases. This dimensional approach simplifies the structure by using sliding motion instead of complex multi-case assemblies.
3Adaptability or versatility
If a loose fit between the diaphragm and battery case is used to accommodate volume changes, then the battery can expand and contract, but electrolyte may leak through the gap
Solution Approach 1:
The diaphragm is designed as a flexible thin film with a movable portion that maintains contact with the battery case wall through friction. This flexible film structure accommodates volume changes while the frictional contact prevents gaps that could allow electrolyte leakage, solving both adaptability and sealing requirements.
4Object-generated harmful factors
If a tight fit between the diaphragm and battery case is used to prevent electrolyte leakage, then sealing is improved, but volume changes cannot be accommodated
Solution Approach 1:
The diaphragm assembly is designed with a movable portion that can dynamically adjust its position to accommodate volume changes. The friction between the movable portion and battery case wall provides a dynamic seal that maintains tight contact during operation while allowing controlled movement, simultaneously achieving both sealing and volume accommodation.
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 improves safety by directing gas discharge away from electrode leads, reducing the risk of fire and enhancing overall battery safety.
Implementation Method 1
a movable portion (152) that is in contact with an inner wall of the battery case and is movable along the inner wall
Implementation Method 2
a separator membrane that is in contact with the electrodes and that surrounds at least a portion of the movable portion
Data Source
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AI summary
Disclosed herein is a secondary battery having a vent member. The secondary battery may include an electrode assembly to which an electrode lead is attached, a battery case including an accommodation portion to receive the electrode assembly therein such that a portion of the electrode lead may extend outside the battery case, a lead film disposed around an outer surface of the electrode lead, and a vent member. The battery case may include a sealing portion containing a sealant resin to form a seal at least partially around the electrode assembly. The lead film may be interposed between the electrode lead and the sealing portion. The vent member may contain a vent resin having a lower melting point than the sealant resin. The vent member may at least partially overlap or contact the lead film.