Copper Foil Vacancy Profile for Curl-Resistant Battery Electrodes
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Solution Overview
Problem
Copper foils used in secondary batteries experience curling, wrinkles, and tears due to thickness reduction, which complicates manufacturing and affects the stability and capacity of the batteries.
Innovation Solution
Control the hydrogen vacancy density within specific ranges at defined depths from the matte and shiny surfaces of the copper foil to stabilize surface characteristics, preventing curling and tears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If copper foil thickness is reduced to increase active material capacity, then battery capacity increases, but curling and tears occur during manufacturing
Solution Approach 1:
The patent applies parameter changes by controlling hydrogen vacancy density at specific depth ranges from the copper foil surface (80-250 counts at 30-45 nm depth, 3-20 counts at 30-45 nm depth from opposite surface). This modifies the physical and chemical properties of the copper foil to suppress curling while maintaining thin thickness, thereby resolving the contradiction between increasing battery capacity through thickness reduction and preventing manufacturing defects
Solution Approach 2:
The patent implements local quality by creating non-uniform hydrogen vacancy distribution at different depths from the copper foil surfaces. The matte surface side has higher hydrogen vacancy density (80-250 counts) compared to the shiny surface side (3-20 counts), providing localized structural characteristics that prevent curling on the matte surface while maintaining overall foil integrity during manufacturing
2Quantity of substance
If copper foil thickness is reduced to increase active material density, then battery energy density increases, but wrinkles and tears occur during winding
Solution Approach 1:
The patent modifies the hydrogen vacancy density parameter within specific ranges (80-250 counts at 30-45 nm from matte surface, 3-20 counts at 30-45 nm from shiny surface) to change the mechanical properties of the copper foil. This parameter control suppresses wrinkle formation and maintains foil stability during the winding process, enabling thinner foils with higher active material density without compromising reliability
Solution Approach 2:
The patent applies preliminary action by pre-controlling the hydrogen vacancy distribution in the copper foil structure before the winding process. This preliminary structural optimization prevents wrinkles and tears from occurring during subsequent manufacturing steps, ensuring foil stability is established in advance rather than attempting to correct defects after they form
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
Prevents curling and tears during manufacturing, enhancing the stability and capacity of secondary batteries by using copper foils with controlled hydrogen vacancy densities.
Implementation Method 1
forming a copper film by electroplating on a cathode plate and a rotating anode drum which are disposed to be spaced apart from each other in an electrolytic cell
Data Source
AI summary
One embodiment of the present disclosure provides a copper foil including a copper film including a matte surface and a shiny surface, wherein a hydrogen vacancy density at a depth of 30 nm to 45 nm from the matte surface ranges from 80 to 250 counts, a hydrogen vacancy density at a depth of 30 nm to 45 nm from the shiny surface ranges from 3 to 20 counts. The hydrogen vacancy density refers to the number of hydrogen ions measured at a certain sputter depth from each of the matte surface and the shiny surface using time of flight-secondary ion mass spectrometry (TOF-SIMS).