Lithium Battery Gasket Adhesive Layer Sealing
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Solution Overview
Problem
Lithium secondary batteries face issues with electrolyte leakage due to inadequate sealing between the cap assembly and the gasket or between the gasket and the cylindrical can, leading to reduced sealing capacity and potential battery failure.
Innovation Solution
A cylinder type lithium secondary battery design incorporates a gasket with an adhesive layer formed by the reaction of the electrolyte and the gasket material, specifically using oriented polystyrene (OPS) for the portion in contact with the electrolyte and polypropylene for the non-contacting portion, providing a sealing pressure of 23.00 kgf/cm2 or higher to enhance sealing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional gasket is used between the cap assembly and cylindrical can, then the battery assembly is simple, but electrolyte leakage occurs due to insufficient sealing capacity
Solution Approach 1:
The gasket material undergoes a chemical parameter change when exposed to electrolyte, transforming from a non-adhesive state to an adhesive state through reaction with the electrolyte components. This parameter change enables the gasket to develop sealing capacity dynamically without requiring complex pre-adhesive structures.
Solution Approach 2:
The gasket serves itself by using the electrolyte present in the battery to activate its adhesive properties. The electrolyte that would otherwise be a simple functional component becomes the activating agent that enables the gasket's sealing function, eliminating the need for separate adhesive layers or complex activation mechanisms.
2Reliability
If the gasket material is made adhesive through electrolyte reaction, then sealing capacity improves, but the gasket material selection becomes more restricted
Solution Approach 1:
The gasket material undergoes a chemical parameter change when exposed to electrolyte, transforming from a non-adhesive state to an adhesive state through reaction with the electrolyte components. This parameter change enables the gasket to develop sealing capacity dynamically without requiring complex pre-adhesive structures.
3Reliability
If higher sealing pressure is required to prevent leakage, then sealing capacity improves, but the stress on the gasket and battery components increases
Solution Approach 1:
The gasket is designed as a single-use, non-recoverable component that is discarded after battery assembly. This allows the use of materials optimized for chemical reaction with electrolyte rather than mechanical recovery, and eliminates the need for expensive, high-strength materials that could withstand repeated assembly cycles.
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 enhanced sealing capacity significantly reduces electrolyte leakage and maintains a sealed state until higher pressures are reached, improving the battery's performance and longevity.
Implementation Method 1
The gasket may include an adhesive layer having a reaction product of the electrolyte and a material of the gasket
Data Source
AI summary
A cylinder type lithium secondary battery may include an electrode assembly, a cylindrical can configured to retain the electrode assembly, a cap assembly coupled to a top opening of the cylindrical can, an electrolyte disposed in the cylindrical can, and a gasket between the cap assembly and the cylindrical can, the gasket including an adhesive layer having a reaction product of the electrolyte and a material of the gasket.