Electrolytic Copper Foil Flexural Endurance
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Solution Overview
Problem
Conventional electrolytic copper foils for secondary batteries face challenges in maintaining physical properties and flexural endurance due to the expansion and contraction of active material layers during charging and discharging, leading to peeling or breaking of the active material layer and degradation of charging and discharging cycle characteristics.
Innovation Solution
The production of electrolytic copper foils using a plating solution containing copper, total organic carbon (TOC), cobalt, and arsenic, with a specific ratio of TOC to cobalt and arsenic, ensures uniform physical properties and high flexural endurance, as evidenced by bending times greater than or equal to 110 in the MIT bending test, and a surface roughness of less than 2.0 μm, thereby enhancing battery lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional electrolytic copper foil is used for secondary batteries, then the production process is simple, but the flexural endurance is poor due to active material layer expansion and contraction during charging and discharging
Solution Approach 1:
The invention changes the chemical composition parameters of the electrolytic solution by adding specific amounts of boron (0.01-0.5 g/L), silicon (0.01-0.5 g/L), and phosphorus (0.01-0.5 g/L) to modify the crystal structure and physical properties of the deposited copper foil, thereby improving flexural endurance and cycle characteristics
Solution Approach 2:
The invention creates a composite electrolytic solution system combining copper sulfate, sulfuric acid, and multiple additives (boron, silicon, phosphorus) that work synergistically to produce copper foil with enhanced mechanical properties and resistance to flexural stress during battery cycling
2Duration of action of moving object
If the active material layer undergoes expansion and contraction during charging and discharging, then the battery can be repeatedly charged and discharged, but the active material layer peels from the collector or the current collector breaks
Solution Approach 1:
The invention modifies the surface properties and mechanical strength of the copper foil by controlling the electrolytic solution composition, particularly the addition of boron, silicon, and phosphorus, which enhance the foil's ability to withstand repeated expansion and contraction stresses without breaking or peeling
3Duration of action of stationary object
If electrolytic copper foil is produced with high flexural endurance, then the battery lifespan is extended, but the production process becomes more complex
Solution Approach 1:
The invention achieves high flexural endurance by optimizing the concentration ranges of additives in the electrolytic solution (boron: 0.01-0.5 g/L, silicon: 0.01-0.5 g/L, phosphorus: 0.01-0.5 g/L), which can be directly controlled during the existing electrolytic deposition process without adding complex production steps
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 solution results in electrolytic copper foils with improved flexural endurance and uniform physical properties, effectively withstanding stress from active material expansion and contraction, thereby extending battery lifespan and maintaining cycle characteristics.
Implementation Method 1
the process of reducing copper ions into metal by the electrolysis method is referred to the foil manufacturing process
Implementation Method 2
copper is electrodeposited on the cathode to enable continuous electrolytic copper foil production
Data Source
AI summary
The present invention relates to an electrolytic copper foil for a secondary battery, having excellent flexural resistance, and a method for producing the electrolytic copper foil. The electrolytic copper foil for a secondary battery has excellent flexural resistance even without the use of many additives in a copper electrolyte when producing a copper foil. The electrolytic copper foil for a secondary battery according to the present invention is an electrolytic copper foil for a secondary battery, which is produced from a plating solution, containing total organic carbon (TOC), cobalt and arsenic, by using a drum and is coated with a negative electrode active material, wherein the ratio between the TOC, cobalt and arsenic contained in the electrolytic copper foil follows the following formula 1:TOC/(cobalt+arsenic)=1.30-1.55. [Formula 1]