Lithium Battery Negative Electrode with Low-PCR Cu Collector Adhesion
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving improved battery characteristics such as lifecycle, high-rate performance, and efficiency due to insufficient adherence between the active material layer and the current collector, often resulting from inadequate surface roughness.
Innovation Solution
A negative electrode design featuring a Cu current collector with a specific X-ray diffraction peak at the (111) plane and a PCR value of 5.0 or less, combined with a carbon-based or Si-including active material, enhances adherence and reduces interface resistance, thereby improving cycle-life and high-rate characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth surface current collector is used, then manufacturing is easier, but adherence between active material layer and current collector is insufficient
Solution Approach 1:
The patent applies parameter changes by controlling the surface roughness of the current collector within a specific range (Ra: 0.3 μm to 3.0 μm) to optimize both manufacturing ease and adherence. This quantitative parameter control resolves the contradiction by finding the optimal roughness level that provides sufficient adherence while maintaining manufacturability.
Solution Approach 2:
The patent applies local quality by creating specific surface characteristics (roughness) only at the interface between the current collector and active material layer, while maintaining smoothness in other areas. This localized surface treatment enhances adherence at the critical interface without compromising overall manufacturing ease.
2Reliability
If surface roughness is increased to improve adherence, then adherence improves, but manufacturing complexity increases
Solution Approach 1:
The patent resolves this contradiction by defining a specific surface roughness parameter range (Ra: 0.3 μm to 3.0 μm) that provides sufficient adherence while avoiding excessive complexity. This quantitative control ensures the surface is rough enough for good adherence but not so rough as to complicate manufacturing processes.
3Productivity
If interface resistance is reduced through better adherence, then high-rate performance improves, but achieving such adherence requires complex surface treatment
Solution Approach 1:
The patent achieves high-rate performance by controlling surface roughness within the optimal range (Ra: 0.3 μm to 3.0 μm), which reduces interface resistance without requiring complex surface treatments. This parameter optimization allows good electrical contact and ion transport while maintaining simple manufacturing processes.
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 proposed design achieves enhanced battery performance by ensuring strong adherence between the active material layer and the current collector, leading to improved cycle-life and high-rate characteristics.
Implementation Method 1
a PCR (Plane angle Change Ratio) value defined by Equation 1 below is about 5.0 or less. In Equation 1, the peak intensity is a value from an X-ray diffraction measurement by using a CuKα ray.
Implementation Method 2
a negative electrode for a rechargeable lithium battery, the negative electrode including a current collector and a negative active material layer including a negative active material on the current collector
Implementation Method 3
electrical energy is produced by oxidation and reduction reactions when lithium ions are intercalated/deintercalated at the positive and negative electrodes
Data Source
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AI summary
The current disclosure includes a negative electrode for a rechargeable lithium battery and a rechargeable lithium battery including the negative electrode. The negative electrode for the rechargeable lithium battery includes a current collector and a negative active material layer including a negative active material on the current collector, wherein a PCR (Plane angle Change Ratio) value is about 5.0 or less.