Lithium Battery Coating Layer Uniformity and Swelling Control
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Solution Overview
Problem
Lithium secondary batteries face issues with uneven coating layers on lithium metal composite oxides, leading to uncoated regions that can cause electrolyte decomposition and battery swelling due to gas generation.
Innovation Solution
A positive electrode active material with a uniformly formed coating layer containing lithium and aluminum or zirconium, ensuring uniform distribution and high lithium ion conductivity, which reduces uncoated regions and prevents electrolyte decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer is provided on the surface of lithium metal composite oxide, then weatherability is improved, but coating uniformity deteriorates leading to uncoated regions
Solution Approach 1:
The patent applies preliminary action by forming the coating layer on the surface of the lithium metal composite oxide before battery assembly. The coating process is performed in advance on the positive electrode active material particles, ensuring that the protective layer is already in place before the material is incorporated into the battery structure. This preliminary coating prevents subsequent exposure of uncoated regions to electrolyte decomposition
Solution Approach 2:
The patent utilizes parameter changes by controlling the coating thickness to be within a specific range (0.1-10 μm) and adjusting the atomic ratio of aluminum to nickel (Al/Ni) to be 0.01-1.0. By optimizing these parameters, the coating achieves sufficient protective coverage while maintaining manufacturing feasibility and preventing uncoated regions from forming
2Ease of manufacture
If coating layer thickness varies, then application ease is improved, but gas generation increases due to uncoated regions
Solution Approach 1:
The patent implements feedback control by establishing specific quantitative criteria for coating quality: the coating thickness is controlled within 0.1-10 μm, and the Al/Ni atomic ratio is maintained at 0.01-1.0. These feedback parameters ensure that the coating provides adequate protection against electrolyte decomposition and gas generation while remaining feasible to manufacture
Solution Approach 2:
The patent changes critical parameters including coating thickness (0.1-10 μm) and compositional ratios (Al/Ni = 0.01-1.0) to optimize the balance between manufacturing ease and gas suppression. By adjusting these parameters, the coating achieves sufficient coverage to prevent electrolyte contact while maintaining practical manufacturability
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 effectively suppresses battery swelling by ensuring a uniform coating layer on lithium secondary battery electrodes, reducing gas generation and enhancing the battery's stability and performance.
Implementation Method 1
such a coating layer is provided for suppressing contact of moisture or carbon dioxide in the air with the central portion of the lithium metal composite oxide
Implementation Method 2
high lithium ion conductivity
Data Source
Figure 1A~1B
Figure 2~3
Figure 4
AI summary
A positive electrode active material for a lithium secondary battery, which includes a lithium-containing composite metal compound in the form of secondary particles that are aggregates of primary particles capable of being doped and undoped with lithium ions, each of the secondary particles having on its surface a coating layer including a metal composite oxide including lithium and aluminum, wherein the positive electrode active material includes at least nickel and aluminum as non-lithium metals, and satisfies all of the requirements (1) to (2).