Composite Battery Substrate Balancing Elongation and Dimensional Stability
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in maintaining structural integrity and safety during the fabrication process, particularly due to deformation and elongation issues.
Innovation Solution
A composite substrate for lithium batteries is designed with a support layer and metal layers on either surface, utilizing polymers with varying tensile strengths and elongations to enhance structural stability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single polymer material is used in the support layer, then the fabrication process is simple, but the battery undergoes deformation and elongation during fabrication
Solution Approach 1:
The support layer is constructed as a composite material consisting of two different polymers with complementary properties. The first polymer provides high elongation to accommodate fabrication processes, while the second polymer provides high tensile strength to maintain dimensional stability. This composite structure resolves the contradiction by combining materials that individually excel at different functions.
Solution Approach 2:
Different regions of the support layer have different polymer compositions tailored to specific functional requirements. The first polymer dominates in regions requiring flexibility and elongation, while the second polymer dominates in regions requiring structural strength and dimensional stability. This local differentiation allows the support layer to simultaneously achieve ease of manufacture and manufacturing precision.
2Strength
If a support layer with high tensile strength is used, then deformation is reduced, but battery safety during fabrication is compromised
Solution Approach 1:
The composite polymer structure allows the first polymer to provide high elongation capacity that enhances battery safety by accommodating expansion and stress during fabrication, while the second polymer provides the necessary tensile strength to prevent deformation. Together, they resolve the contradiction between strength and safety.
Solution Approach 2:
The invention changes the material parameters by selecting polymers with specific tensile strength and elongation characteristics. The first polymer is selected for high elongation (greater than the second polymer), while the second polymer is selected for high tensile strength (greater than the first polymer). This parameter optimization allows the support layer to simultaneously achieve strength and safety.
3Reliability
If a support layer with high elongation is used, then battery safety is improved, but deformation during fabrication increases
Solution Approach 1:
The composite structure combines the first polymer with high elongation (for safety) and the second polymer with high tensile strength (for dimensional stability). The synergistic interaction between these two polymers resolves the contradiction by allowing the support layer to both elongate safely and maintain dimensional precision during fabrication.
Data Source
AI summary
Disclosed are composite substrates, and rechargeable lithium batteries including the composite substrates. A composite substrate includes a support layer, a first metal layer on a top surface of the support layer, and a second metal layer on a bottom surface of the support layer. The support layer includes a first polymer and a second polymer that are different from each other. A tensile strength of the second polymer is greater than a tensile strength of the first polymer. An elongation of the first polymer is greater than an elongation of the second polymer.