Protective Copper Foil for Stable Electrode Adhesion in Batteries
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Solution Overview
Problem
Existing copper foils used in secondary batteries suffer from poor adhesion to active materials, leading to rapid capacity degradation and short lifespan, necessitating frequent replacement and resource waste.
Innovation Solution
A copper foil with a protective layer and specific thermal deformation indices, ranging from 15 to 50, ensuring excellent adhesion to active materials under varying environmental conditions, enhancing capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional copper foils are used as current collectors, then manufacturing cost is low and electrical conductivity is high, but adhesion to active materials is poor leading to rapid capacity degradation
Solution Approach 1:
The patent applies composite materials by combining copper with specific alloying elements (Sn, Ni, Zn, Pb, or Ag) to create a copper-based alloy foil. This composite structure provides both the electrical conductivity of copper and enhanced adhesion properties through the alloying elements, directly resolving the contradiction between good adhesion and high electrical conductivity.
Solution Approach 2:
The patent changes the chemical composition parameters of the copper foil by controlling the content of specific elements (Cu: 99.9-99.99%, Sn: 0.01-0.5%, Ni: 0.01-0.5%, Zn: 0.01-0.3%, Pb: 0.01-0.1%, Ag: 0.01-0.1%) to optimize both adhesion and electrical conductivity. This parameter optimization resolves the technical contradiction by finding the optimal composition range.
2Reliability
If copper foil with high adhesion is used, then capacity retention rate improves, but manufacturing complexity increases
Solution Approach 1:
The patent controls manufacturing parameters within specific ranges (alloying element contents, thickness: 6-12 μm, thermal deformation index: 15-50) to achieve high adhesion without requiring complex manufacturing processes. The electrorefining or electrolytic refining methods used are standard industrial processes, maintaining manufacturing simplicity while achieving the desired performance.
3Reliability
If copper foil with optimized thermal deformation index is used, then adhesion under thermal stress improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the thermal deformation index by controlling the alloying element composition and foil thickness. The specific parameter ranges (thermal deformation index: 15-50, thickness: 6-12 μm) are designed to achieve stable adhesion under thermal conditions while being manufacturable with standard precision levels.
Solution Approach 2:
The patent applies different alloying element distributions and surface treatments to specific regions or surfaces of the copper foil to enhance local adhesion properties under thermal stress, while maintaining overall manufacturing feasibility with standard precision requirements.
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 maintains high capacity retention rates, extending the lifespan of secondary batteries and reducing consumer inconvenience and resource waste.
Implementation Method 1
the copper foil has a room-temperature thermal deformation index ranging from 15 to 50
Data Source
AI summary
One embodiment of the present disclosure provides a copper foil including a copper film including 99.9 wt % or more of copper, and a protective layer disposed on the copper film, wherein the copper foil has a room-temperature thermal deformation index ranging from 15 to 50. The room-temperature thermal deformation index is expressed by Equation 1 below,room-temperature thermal deformation index=(room- temperature thermal expansion coefficient (ppm/° C.)+ room-temperature elongation (%))/surface area ratio.[Equation 1]