Electrolytic Copper Foil Composition for Stable Battery Elongation
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Solution Overview
Problem
The existing electrolytic copper foils for secondary batteries experience changes in physical properties due to variations in crosshead speed during tensile strength and elongation percentage measurements, leading to degradation of charging/discharging characteristics and cracking or exfoliation of active materials, which shortens battery life.
Innovation Solution
Incorporating Total Organic Carbon (TOC) and cobalt and iron as metallic additives in the copper electrolyte, with a specific ratio of TOC to cobalt and iron, and controlling the crosshead speed differences to maintain consistent tensile strength and elongation percentage, ensuring the electrolytic copper foil's physical properties remain stable across different measurement speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrolytic copper foil is produced by conventional electrolysis method, then copper foil can be continuously produced, but the physical properties change when crosshead speed varies during tensile testing
Solution Approach 1:
The patent modifies the electrolyte composition parameters by adding specific organic additives (carboxylic acid and its derivative) to control the crystal structure transformation during electroplating. This chemical parameter change ensures that the copper foil's physical properties remain consistent regardless of crosshead speed variations during tensile testing, while maintaining continuous production capability
Solution Approach 2:
The patent creates a composite electrolyte system combining traditional electrolyte components with organic additives (carboxylic acid and derivative). This composite approach modifies the deposition process to produce copper foil with stable physical properties that are insensitive to testing conditions, resolving the contradiction between continuous production and property consistency
2Loss of time
If crosshead speed difference is large during tensile testing, then testing can be completed quickly, but charging/discharging characteristics of battery degrade
Solution Approach 1:
By changing the electrolyte composition to include carboxylic acid and its derivative, the patent produces copper foil with a stabilized crystal structure. This structural stability ensures that charging/discharging characteristics remain excellent regardless of crosshead speed variations during tensile testing, effectively decoupling testing time from battery performance
3Device complexity
If conventional electrolytic copper foil is used, then production process is simple, but crystal structure transforms during electroplating causing physical property changes
Solution Approach 1:
The patent introduces organic additives (carboxylic acid and derivative) into the electrolyte at specific concentrations (0.01-5 g/L). This compositional parameter change prevents unwanted crystal structure transformation during electroplating, maintaining crystal structure stability without significantly complicating the production process
Solution Approach 2:
The carboxylic acid and its derivative act as intermediary substances in the electrolyte that mediate between the electric field and copper ion deposition. These intermediaries control the electroplating process to produce a stable crystal structure, preventing transformation while keeping the process relatively simple
4Quantity of substance
If electrolytic copper foil lacks stable physical properties, then production cost is low, but active material cracks or exfoliates shortening battery life
Solution Approach 1:
The patent modifies electrolyte composition parameters by adding small amounts of carboxylic acid and its derivative (0.01-5 g/L). This cost-effective parameter change produces copper foil with stable physical properties that prevent active material cracking and exfoliation, significantly extending battery life without substantially increasing production cost
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
This approach prevents crystal structure transformation and maintains excellent charging/discharging characteristics, reducing the likelihood of battery cracking and active material exfoliation, thereby extending battery life and ensuring consistent performance.
Implementation Method 1
the electrolytic copper foil is generated by an electrolysis method
Implementation Method 2
copper is electrodeposited in the negative electrode, thereby continuously producing the electrolytic copper foil
Data Source
AI summary
The present invention relates to an electrolytic copper foil for a secondary battery, and a method of producing the same. The electrolytic copper foil for a secondary battery exhibits a little change in a physical property caused by a difference in a crosshead speed when tensile strength and an elongation percentage of the electrolytic copper foil are measured, thereby achieving excellent charging and discharging characteristics of a battery and preventing exfoliation of an active material. The electrolytic copper foil for a secondary battery is produced from a plating solution containing Total Organic Carbon (TOC), cobalt, and iron by using a drum, in which a ratio of the TOC to the cobalt and the iron contained in the electrolytic copper foil follows Formula 1 below.TOC/(cobalt+iron)=1.3 to 1.5 [Formula 1]