Battery Binder Layer Structure for Compression Safety
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Solution Overview
Problem
Lithium-ion batteries face safety issues when subjected to external forces or impacts, leading to structural disruption, short circuits, heating, and potential fires, which compromise their safety performance.
Innovation Solution
An electrochemical device design featuring a packaging bag, electrode assembly, and a binder with specific peel strengths and tensile strengths for the bonding layers, along with a substrate layer, to enhance mechanical consistency and resistance-to-compression, using materials like acrylic compounds and aluminum for improved safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a binder with specific peel strength and tensile strength is introduced to bond the electrode assembly to the packaging bag, then the resistance-to-compression and safety performance are improved, but the device complexity increases
Solution Approach 1:
The binder is divided into multiple functional layers (first bonding layer, substrate layer, second bonding layer) with distinct functions. Each layer is optimized for its specific role: the first bonding layer provides adhesion to the electrode assembly with controlled peel strength F1, the substrate layer provides mechanical strength with tensile strength 100-2000 MPa, and the second bonding layer provides adhesion to the packaging bag with peel strength F2. This segmentation allows each layer to be independently optimized while working together to improve overall safety performance.
Solution Approach 2:
The binder employs a composite structure combining different materials with complementary properties. The first bonding layer uses materials with peel strength F1 of 50-1000 N/m to bond to the electrode assembly, the substrate layer uses materials with tensile strength of 100-2000 MPa for mechanical reinforcement, and the second bonding layer uses materials with peel strength F2 for packaging bag adhesion. This composite approach enables the binder to simultaneously provide adhesion, mechanical strength, and controlled failure characteristics, improving safety without excessive complexity.
2Strength
If the peel strength F1 between the first bonding layer and the electrode assembly is increased to improve bonding, then the resistance-to-compression improves, but the risk of structural disruption under impact increases
Solution Approach 1:
The patent precisely controls the peel strength parameter F1 of the first bonding layer within the range of 50-1000 N/m, and the ratio F1/F2 within 1-10. This parameter optimization ensures sufficient bonding strength to prevent separation under compression while allowing controlled deformation and energy absorption during impact. The substrate layer's tensile strength is also controlled at 100-2000 MPa to provide mechanical reinforcement without being excessively rigid, thereby balancing bonding strength with impact resistance.
3Strength
If the tensile strength of the substrate layer is increased to enhance mechanical properties, then the resistance-to-compression improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The substrate layer's tensile strength is optimized within the range of 100-2000 MPa, providing sufficient mechanical reinforcement to improve resistance-to-compression while maintaining manufacturability. This parameter range ensures the substrate layer can withstand compression forces and maintain structural integrity without requiring excessively complex manufacturing processes or specialized materials that would significantly increase production difficulty.
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 design improves the electrochemical device's resistance to compression and mechanical integrity, enhancing safety performance by preventing structural failure and fire risks under external stress.
Implementation Method 1
The first bonding layer adheres to a surface of the electrode assembly. A peel strength between the first bonding layer and the electrode assembly is F1
Implementation Method 2
The second bonding layer adheres to a surface that is of the packaging bag and that is closer to the electrode assembly. a peel strength between the second bonding layer and the packaging bag is F2
Implementation Method 3
A tensile strength of the substrate layer is 100 MPa to 2000 MPa
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
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 closer to the electrode assembly. A peel strength between the first bonding layer and the electrode assembly is Fi, a peel strength between the second bonding layer and the packaging bag is F2, and the peel strengths satisfy 50 N/m ≤ Fi ≤ 1000 N/m and 1 ≤ F1/F2 ≤ 10. A tensile strength of the substrate layer is 100 MPa to 2000 MPa.