Composite Battery Substrate With Rough Porous Layers for Adhesion
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in achieving high energy density and capacity, with existing substrates lacking sufficient electrical conductivity and adhesion to active material layers, leading to issues like delamination and reduced performance.
Innovation Solution
A composite substrate comprising a fiber mat layer with a porosity of 30% to 70% and metal layers on either side, featuring an uneven surface roughness of 1 μm to 3 μm, enhances electrical conductivity and adhesion to active material layers through a manufacturing process involving electrospinning and rolling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional substrate is used, then the battery structure is simple, but the electrical conductivity and adhesion to active material layer are insufficient
Solution Approach 1:
The patent employs a composite substrate consisting of a fiber mat layer (made of polyolefin or ceramic fibers) combined with metal layers (aluminum or copper). This composite structure achieves both high electrical conductivity and strong adhesion to the active material layer, while maintaining structural simplicity and avoiding delamination issues.
2Weight of moving object
If the substrate porosity is increased to reduce weight, then the electrical conductivity may decrease
Solution Approach 1:
The fiber mat layer is designed with controlled porosity (30-70%) to reduce substrate weight while maintaining structural integrity. The porous fiber mat provides lightweight structure that still supports the metal layers and maintains adequate electrical conductivity through the metal pathways.
Solution Approach 2:
The combination of porous fiber mat with conductive metal layers creates a composite that achieves both weight reduction and maintained electrical conductivity. The fiber mat provides lightweight porous structure while the metal layers ensure electrical conductivity pathways.
3Reliability
If the surface roughness is increased to improve adhesion, then the manufacturing precision may be compromised
Solution Approach 1:
The fiber mat layer provides localized surface roughness at the micro-scale level, creating anchoring points for the active material layer without requiring overall surface irregularities. This local quality approach improves adhesion through mechanical interlocking while maintaining manageable manufacturing precision.
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 composite substrate improves adhesion and conductivity, reducing weight and thermal conduction while preventing defects like delamination, and provides enhanced safety by minimizing fire risks from short-circuits.
Implementation Method 1
a first metal layer, a second metal layer, and a fiber mat layer between the first metal layer and the second metal layer
Implementation Method 2
a desired or improved adhesion force to an active material layer
Data Source
AI summary
Disclosed are composite substrates and rechargeable lithium batteries. The composite substrate includes a first metal layer, a second metal layer, and a fiber mat layer between the first metal layer and the second metal layer. The fiber mat layer includes a plurality of fibers and a plurality of voids between the plurality of fibers. The composite substrate has a first surface on which the first metal layer is formed, and a second surface on which the second metal layer is formed. An average roughness (Sa) of the first surface is in a range of about 1 μm to about 3 μm.