Battery Binder Structure for Compression-Resistant Pouch Cells
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Solution Overview
Problem
Lithium-ion batteries face safety concerns due to structural disruption, short circuits, and thermal runaway when subjected to external forces or foreign object impacts, which compromise their safety performance.
Innovation Solution
An electrochemical device with a packaging bag, electrode assembly, and a binder comprising a first and second bonding layer, and a substrate layer, where the peel strengths and tensile strength are controlled to ensure consistent mechanical properties, enhancing resistance-to-compression and safety performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a binder with high peel strength is used to bond the electrode assembly to the packaging bag, then the bonding reliability is improved, but the mechanical property consistency between components deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the peel strength of the binder within a specific range (50-1000 N/m) and the tensile strength of the substrate layer (100-2000 MPa). This quantitative parameter optimization ensures that the binder provides sufficient bonding reliability while maintaining mechanical property consistency across all components, resolving the contradiction between strong bonding and mechanical consistency.
Solution Approach 2:
The binder is designed as a composite structure comprising a first bonding layer, a substrate layer, and a second bonding layer. This composite material approach allows each layer to contribute different properties: the bonding layers provide adhesion to electrode and packaging bag surfaces, while the substrate layer provides mechanical strength. The composite structure enables simultaneous achievement of high bonding reliability and mechanical property consistency.
2Strength
If the packaging bag, electrode assembly, and binder form a unified structure with consistent mechanical properties, then the resistance-to-compression is improved, but the complexity of the binder structure increases
Solution Approach 1:
The binder is segmented into three functional layers: a first bonding layer for adhering to the electrode assembly, a substrate layer for providing mechanical strength, and a second bonding layer for adhering to the packaging bag. This segmentation allows each layer to be optimized for its specific function while collectively achieving high resistance-to-compression. The modular segmented structure manages complexity by assigning specific roles to each layer.
Solution Approach 2:
The binder structure serves multiple functions simultaneously: the bonding layers provide adhesion functionality, the substrate layer provides mechanical reinforcement, and together they create a unified structure that improves resistance-to-compression. This multi-functionality approach consolidates multiple requirements (bonding, strength, compression resistance) into a single integrated component, managing overall device complexity.
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 controlled peel strengths and tensile strength of the binder and substrate layer improve the mechanical integrity of the electrochemical device, reducing the risk of short circuits and thermal runaway, thereby enhancing the safety performance of lithium-ion batteries.
Implementation Method 1
The binder is configured to bond the electrode assembly to the packaging bag. The binder includes a first bonding layer, a substrate layer, and a second bonding layer that are stacked in sequence. The first bonding layer adheres to a surface of the electrode assembly. The second bonding layer adheres to a surface that is of the packaging bag and that is close to the electrode assembly.
Data Source
AI summary
An electrochemical device includes a packaging bag, an electrode assembly, and a binder. The electrode assembly is disposed in the packaging bag. The binder is configured to bond the electrode assembly to the packaging bag. The binder includes a first bonding layer, a substrate layer, and a second bonding layer that are stacked in sequence. The first bonding layer adheres to a surface of the electrode assembly. The second bonding layer adheres to a surface that is of the packaging bag and that is close to the electrode assembly. A peel strength between the first bonding layer and the electrode assembly is F1, a peel strength between the second bonding layer and the packaging bag is F2, and the peel strengths satisfy 50 N/m≤F1≤1000 N/m and 1≤F1/F2≤10. A tensile strength of the substrate layer is 100 MPa to 2000 MPa.