Composite Current Collector Layout for Stacked Lithium Battery Cells
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Solution Overview
Problem
There is a growing demand for rechargeable lithium batteries with high energy density and capacity to power devices such as mobile phones and electric vehicles, but existing technologies have limitations in achieving optimal performance.
Innovation Solution
The use of a composite current collector in rechargeable lithium batteries, comprising a support layer and metal layers, with active material layers on either side, allows for improved electrical connectivity and mechanical stability, enabling higher energy density and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a composite current collector with multiple metal layers is used, then mechanical stability and electrical connectivity are improved, but device complexity increases
Solution Approach 1:
The current collector uses a composite structure comprising a copper foil base layer with aluminum foil surface layers, where each layer has specific thickness ratios (Cu:Al = 1:0.5 to 1:2). This composite material design provides both mechanical strength from the copper base and electrochemical stability from the aluminum surface, resolving the contradiction between strength and complexity by using a standardized multi-layer composite rather than a single complex material.
Solution Approach 2:
The composite current collector structure serves multiple functions simultaneously: the copper foil provides mechanical support and electrical conductivity, while the aluminum foil layers provide electrochemical stability and prevent dendrite formation. This multi-functionality integrated into a single component reduces overall device complexity while maintaining high mechanical stability.
2Quantity of substance
If active material layers are coated on both sides of the current collector, then energy density is improved, but manufacturing precision requirements increase
Solution Approach 1:
The battery structure is segmented into multiple unit cells, each with its own current collector having active material layers on both sides. This segmentation allows independent coating processes for each side, making it easier to control coating uniformity and thickness while maximizing the use of active material to improve energy density.
Solution Approach 2:
The patent specifies precise thickness parameters for each layer (copper foil 5-20 μm, aluminum foil 2-10 μm each side) to optimize both energy density and manufacturing feasibility. By controlling these parameters within specific ranges, the patent achieves high energy density while maintaining manufacturability through standardized thickness specifications.
3Volume of moving object
If composite current collectors with controlled thickness ratios are used, then spatial utilization is improved, but manufacturing complexity increases
Solution Approach 1:
The patent defines specific thickness ratio parameters (Cu:Al = 1:0.5 to 1:2) that optimize spatial utilization by maximizing active material volume while maintaining structural integrity. These parameter specifications enable standardized manufacturing processes, reducing complexity despite the multi-layer structure by providing clear target values for production control.
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 current collector design enhances the mechanical stability and spatial utilization of lithium batteries, leading to improved performance and efficiency.
Implementation Method 1
the rechargeable lithium battery generates electrical energy caused by oxidation and reduction reactions when lithium ions are intercalated and deintercalated
Data Source
AI summary
Disclosed are rechargeable lithium batteries and fabrication methods thereof. The rechargeable lithium battery includes unit cells that are stacked, and a separator between the unit cells. At least one of the unit cells includes a composite current collector that has a top surface and a bottom surface that are opposite to each other, a first active material layer on the top surface of the composite current collector, and a second active material layer on the bottom surface of the composite current collector. The composite current collectors of neighboring unit cells are in contact with each other.