High-Heat CID Gasket for Cylindrical Battery Stability
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Solution Overview
Problem
Lithium secondary batteries, particularly cylindrical types, suffer from low stability due to decomposition reactions and dendrite growth during overcharging, leading to potential ignition and explosion, as the current interrupt device (CID) gasket melts during external short circuits, reconnecting current and increasing internal temperature.
Innovation Solution
A cap assembly for cylindrical secondary batteries incorporating a CID gasket made of a polymer resin with a melting point of 250°C or more and a heat deflection temperature (HDT) of 200°C or more, or a composite with ceramic, to prevent melting and maintain stability during external short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional CID gasket made of polymer resin with low melting point is used, then the battery structure is simple and easy to manufacture, but the gasket melts during external short circuits causing current reconnection and thermal runaway
Solution Approach 1:
The patent changes the key parameter of the gasket material by specifying a polymer resin with a melting point of 250°C or more and heat deflection temperature of 200°C or more. This parameter change ensures the gasket maintains structural integrity during external short circuits, preventing current reconnection and thermal runaway while maintaining manufacturing simplicity
Solution Approach 2:
The patent employs composite material construction by combining polymer resin with ceramic particles (5-50 wt%). This composite structure provides both the high-temperature resistance needed for safety and the sealing properties required for the CID function, resolving the contradiction between reliability and material complexity
2Reliability
If the gasket material has high heat resistance, then current reconnection is prevented during external short circuits, but manufacturing precision requirements increase
Solution Approach 1:
The patent establishes specific parameter ranges for the polymer resin (melting point ≥250°C, heat deflection temperature ≥200°C) that balance high-temperature performance with manufacturability. These parameter specifications ensure current blocking stability while remaining achievable through conventional manufacturing processes
Solution Approach 2:
The patent applies local quality by incorporating ceramic particles (5-50 wt%) specifically into the gasket material composition. This localized enhancement of heat resistance through composite materials provides the necessary current blocking stability without requiring precision control across the entire battery manufacturing process
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 high-heat-resistant CID gasket prevents current reconnection and internal temperature increase, enhancing the stability and safety of cylindrical secondary batteries by suppressing structural deformation and maintaining air tightness even under severe conditions.
Implementation Method 1
a gasket for the current interrupt device surrounding an outer circumferential surface of the current interrupt device, wherein the gasket for the current interrupt device comprises a polymer resin having a melting point of 250° C. or more and a heat deflection temperature (HDT) of 200° C. or more
Implementation Method 2
the gasket for the current interrupt device comprises a polymer resin having a melting point of 250° C. or more and a heat deflection temperature (HDT) of 200° C. or more
Data Source
AI summary
The present invention relates to a cap assembly formed of a composite of cap assembly ceramic for the cylindrical battery and mounted on a top end portion of the cylindrical secondary battery in which an electrode assembly is placed in a cylindrical can, which includes a safety vent having a predetermined notch configured to be ruptured by high pressure gas generated in the battery, a current interrupt device coupled to a lower end of the safety vent and blocking a current when an internal pressure of the battery rises, and a gasket for the current interrupt device surrounding an outer circumferential surface of the current interrupt device, wherein the gasket for the current interrupt device comprises a polymer resin having a melting point of 250° C. or more and a heat deflection temperature (HDT) of 200° C. or more, and a cylindrical secondary battery including the same.