Dual Encapsulation System for Lithium-Ion Battery Sealing
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Solution Overview
Problem
Lithium-ion batteries face challenges with short-circuiting due to leakage currents, moisture sensitivity, and premature aging, leading to reduced lifespan and capacity, as existing encapsulation methods are not fully impervious and flexible enough to accommodate dimensional changes during charge cycles.
Innovation Solution
A dual encapsulation system comprising a primary and additional encapsulation layer, where the primary layer is made from materials like parylene and polyimide, and the additional layer from glasses or ceramics, providing enhanced imperviousness and flexibility to prevent moisture and gas diffusion, while allowing for electrical contact and accommodating battery dimension changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single encapsulation layer is used to protect the battery, then the manufacturing process is simple, but the encapsulation is not sufficiently impervious to moisture and gas diffusion
Solution Approach 1:
The patent applies composite materials by combining multiple encapsulation layers with different properties: a primary encapsulation layer (polymer-based for flexibility) and a secondary encapsulation layer (glass or ceramic for superior barrier properties). This composite structure achieves both high imperviousness to moisture and gas diffusion while maintaining manufacturing feasibility through sequential deposition processes.
Solution Approach 2:
The encapsulation system is segmented into distinct functional layers: the primary encapsulation layer provides mechanical protection and flexibility, while the secondary encapsulation layer provides the barrier function. This segmentation allows each layer to be optimized for its specific function, with the secondary layer being selectively applied to areas requiring enhanced moisture and gas barrier properties.
2Reliability
If a rigid encapsulation material is used to provide impervious sealing, then moisture and gas diffusion is reduced, but the encapsulation cannot accommodate dimensional changes during charge cycles
Solution Approach 1:
The patent applies local quality by using different material properties in different regions of the encapsulation system. The primary encapsulation layer uses flexible polymer materials that can accommodate dimensional changes, while the secondary encapsulation layer uses rigid glass or ceramic materials for superior barrier properties. This local differentiation allows the system to simultaneously achieve both flexibility and imperviousness.
Solution Approach 2:
The composite encapsulation structure combines flexible polymer-based primary encapsulation with rigid glass or ceramic secondary encapsulation. The flexible primary layer absorbs dimensional changes during charge cycles, while the rigid secondary layer provides the impervious barrier, allowing both requirements to be satisfied simultaneously.
3Duration of action of stationary object
If the encapsulation is made completely impervious, then battery life is extended, but manufacturing precision requirements increase due to the need for perfect sealing
Solution Approach 1:
The patent applies preliminary action by first forming the primary encapsulation layer that provides a base level of protection and a relatively forgiving substrate. Then the secondary encapsulation layer is applied to provide the enhanced barrier properties. This sequential approach with the primary layer first reduces the precision requirements for the final sealing, as the primary layer already provides a foundation that compensates for minor manufacturing variations.
Solution Approach 2:
The composite encapsulation system distributes the sealing function across multiple layers, reducing the precision burden on any single layer. The primary encapsulation layer provides a tolerance buffer, while the secondary layer provides the final barrier, allowing for more relaxed manufacturing precision requirements compared to a single-layer system that would need to achieve perfect sealing in one step.
4Reliability
If thick encapsulation layers are used to prevent moisture permeation, then WVTR is reduced, but the battery device volume increases
Solution Approach 1:
The patent uses composite materials where the secondary encapsulation layer (glass or ceramic) provides exceptional barrier properties with very thin thickness (nanometer to micrometer scale). This allows achieving ultra-low WVTR values without requiring thick encapsulation layers, thus maintaining compact battery volume while providing superior moisture protection.
Solution Approach 2:
The patent changes the material parameter of the encapsulation layer by using glass or ceramic materials with inherently superior barrier properties compared to conventional polymers. This material parameter change enables achieving the same or better WVTR performance with significantly reduced thickness, thereby preventing battery volume increase.
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 dual encapsulation system significantly extends the battery's lifespan by reducing self-discharge and preventing short-circuits, ensuring a long life and high reliability of lithium-ion batteries by maintaining a low water vapor transmission rate and protecting against environmental factors.
Implementation Method 1
providing enhanced imperviousness and flexibility to prevent moisture and gas diffusion
Implementation Method 2
allowing for electrical contact and accommodating battery dimension changes
Data Source
AI summary
A battery including a stack alternating between at least one anode and at least one cathode, a primary encapsulation system covering some of the faces of the stack, at least one anode contact member operable to make electrical contact between the stack and an external conductive element, and at least one cathode contact member operable to make an electrical contact between the stack and an external conductive element. An additional encapsulation system includes two frontal regions respectively covering a respective frontal region of the primary encapsulation system and two lateral regions which cover a respective lateral region devoid of any contact member of the primary encapsulation system. Each of the two frontal regions of the additional encapsulation system further cover the frontal ends respectively of the anode contact members and the cathode contact members. The frontal regions of the additional encapsulation system form a surface continuity with the lateral regions of the additional encapsulation system.