Lithium-Ion Battery Packaging Composite Without Aluminum Foil
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Solution Overview
Problem
Existing lithium ion battery packaging technologies face safety issues due to the reaction between aluminum foil and hydrofluoric acid, short-circuit risks from thermal bonding with metal terminals, and high construction costs associated with complex machining and chromium processing.
Innovation Solution
A multilayer composite structure replaces metal aluminum foil with a water-blocking additive, enhancing compatibility between the outer and inner layers to reduce construction processes and costs, while maintaining safety performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum foil is used as the middle water-blocking layer, then good water-blocking effect is achieved, but safety problem is introduced due to reaction with hydrofluoric acid
Solution Approach 1:
The patent removes the aluminum foil layer from the packaging structure entirely. Instead of modifying the aluminum foil to resist hydrofluoric acid, the invention extracts this problematic component and replaces it with alternative water-blocking materials such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) films that provide equivalent water-blocking performance without chemical reactivity issues.
Solution Approach 2:
The patent employs disposable polymer films (PET or PEN) as replacement for the aluminum foil layer. These films are designed to be consumed or replaced if needed, providing a cost-effective and safe alternative that eliminates the safety hazards associated with aluminum foil while maintaining the essential water-blocking function.
2Strength
If thermal bonding resin is added between outer layer and metal water-blocking layer, then combination strength is improved, but device complexity and construction cost increase
Solution Approach 1:
The patent combines the water-blocking function and the bonding function into a single polymer film layer. The PET or PEN film serves both as the water-blocking barrier and as the adhesive layer that bonds the outer and inner layers together, eliminating the need for separate thermal bonding resin and simplifying the overall structure and construction process.
Solution Approach 2:
The polymer film (PET or PEN) is designed to perform multiple functions simultaneously: it provides water-blocking protection, serves as an adhesive bonding layer between the outer and inner layers, and contributes to the mechanical strength of the packaging structure. This multi-functionality reduces the number of components and simplifies the construction process.
3Strength
If chromium processing is applied to improve bonding strength, then combination strength is improved, but manufacturing cost and environmental impact increase
Solution Approach 1:
The patent removes the chromium processing step from the manufacturing process by eliminating the aluminum foil layer that requires such treatment. The polymer films (PET or PEN) used as replacements do not require chromium processing or any special surface treatment to achieve adequate bonding, significantly simplifying the manufacturing process and reducing costs.
Solution Approach 2:
The patent employs polymer films that can be directly bonded without expensive chromium processing. These disposable or replaceable films provide adequate bonding strength through their inherent adhesive properties or simple thermal bonding, eliminating the need for costly and environmentally harmful chromium conversion coatings.
4Reliability
If metal connection terminal is thermally bonded, then sealing is achieved, but short-circuit risk is introduced
Solution Approach 1:
The patent introduces a polymer film (PET or PEN) as an intermediary material between the metal connection terminals and the packaging structure. This film acts as an electrical insulator that prevents direct thermal contact and potential short-circuits between metal terminals, while still allowing effective sealing and bonding to be achieved through the film medium.
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 solution improves safety by eliminating the risk of hydrofluoric acid reaction, reduces short-circuit risks, and lowers construction costs, while maintaining effective water vapor blocking and mechanical strength.
Implementation Method 1
both layers contain a water-blocking additive
Implementation Method 2
the outer layer and the inner layer have good compatibility, and thus the outer layer and the inner layer can be combined without the need for a transition layer
Data Source
AI summary
A multilayer composite structure for packaging a lithium ion battery and a preparation method thereof and a lithium ion battery are provided. The multilayer composite structure includes mutually-attached inner-layer connection layer film and outer-layer framework structure layer film, which both contain a water-blocking additive. In the existing external layered products, a composite structure of three or more layers is usually adopted, which includes an outer layer with high mechanical strength, a middle layer capable of preventing water vapor invasion, an inner layer having good thermal bonding performance, and a transition layer therebetween. The multilayer composite structure simplifies this structure, where a water-blocking additive is used to replace a metal aluminum foil to prevent invasion of the water vapor, and by using the characteristics of good compatibility of the outer layer and inner layer, the construction processes and costs are reduced, so as to increase to the safety performance.