Battery Copper Foil Composition for Curl and Tear Resistance
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Solution Overview
Problem
Copper foils used in secondary batteries are prone to curling, wrinkling, or tearing during manufacturing due to their thin thickness, which affects the production of high-capacity and high-efficiency batteries.
Innovation Solution
A copper foil with an R value of 2.0 to 3.5, a room temperature loss factor of 0.05 or less, and a high-temperature loss factor of 0.2 or less, manufactured using a specific electrolytic process with controlled additives, prevents curling, wrinkling, and tearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If copper foil thickness is reduced to increase battery capacity, then the amount of active materials that can be included increases and battery capacity increases, but curling occurs and defects such as tears or wrinkles occur during manufacturing
Solution Approach 1:
The patent applies parameter changes by controlling the R-value (a measure of work hardening) within a specific range of 2.0 to 3.5, and controlling the thickness uniformity within ±1 μm. These parameter optimizations allow the copper foil to maintain structural integrity and prevent curling even at reduced thicknesses, thereby enabling increased battery capacity without sacrificing manufacturing precision
2Productivity
If copper foil thickness is reduced to increase battery capacity, then the number of current collectors that can be increased, but curling occurs making manufacturing difficult
Solution Approach 1:
The patent optimizes the R-value parameter to a range of 2.0 to 3.5 and controls thickness uniformity within ±1 μm. These parameter changes fundamentally alter the mechanical properties of the copper foil, reducing curling tendency and making thin-film manufacturing significantly easier, thereby enabling increased productivity through higher numbers of current collectors
3Volume of moving object
If copper foil is made thinner to increase energy density, then space utilization improves, but defects such as tears or wrinkles occur during winding
Solution Approach 1:
The patent implements parameter changes by precisely controlling the R-value within 2.0 to 3.5 and thickness uniformity within ±1 μm. These parameter optimizations enhance the copper foil's resistance to curling and deformation, ensuring reliability and preventing defects such as tears or wrinkles during the winding process while maintaining high space utilization
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 copper foil ensures stable production of secondary batteries by preventing defects, enhancing productivity and maintaining the integrity of the manufacturing process.
Implementation Method 1
a method for manufacturing the copper foil
Data Source
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AI summary
One embodiment of the present invention relates to a copper foil comprising a copper film, which contains 99.9 wt% or more of copper, and having an R value of 2.0-3.5. R is calculated by relation 1, [relation 1] R = log (WA / WB) / log (tA / tB). WA in relation 1 is calculated by relation 2, [relation 2] WA = [XA0 + (XA45) X 2 + XA90] / 4. WB in relation 1 is calculated by relation 3, [relation 3] WB = [XB0 + (XB45) X 2 + XB90] / 4. tA in relation 1 means the thickness of a specimen before a tensile test, tB in relation 1 means the thickness of the specimen after a tensile test, XA0, XA45, and XA90 in relation 2 mean respective widths of the central part, in the direction of tension before applying tension, of specimens collected in 0°, 45°, and 90° directions, and XB0, XB45, and XB90 in relation 3 mean respective widths of the central part, in the direction of tension after applying tension, of the specimens collected in 0°, 45°, and 90° directions. One embodiment of the present invention relates to the copper foil comprising a copper film, which contains 99.9 wt% or more of copper, the copper film having a room-temperature loss coefficient of 0.05 or less, wherein the room-temperature loss coefficient is calculated by relation 4. [relation 4] room-temperature loss coefficient=room-temperature loss modulus/room-temperature storage modulus.