Non-aqueous Electrolyte Battery with Optimized Particle Packing
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Solution Overview
Problem
Nonaqueous electrolyte secondary batteries face challenges in ion migration and load characteristics, particularly during high-rate discharge, due to side reactions and gas generation, which are not adequately addressed by existing technologies.
Innovation Solution
Incorporating a positive electrode mixture layer with a lithium-containing composite oxide and inactive particles, where the average particle size of the active material is larger than that of the inactive particles, and maintaining a nonaqueous electrolyte viscosity less than 2 mPa·s at 30°C, to enhance lithium ion migration paths and suppress side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium nickel composite oxide is used as positive electrode active material, then discharge capacity is improved, but gas generation occurs due to side reactions with nonaqueous electrolyte at high temperature
Solution Approach 1:
An alumina coating layer is applied to the surface of the lithium nickel composite oxide particles, serving as an intermediary barrier between the active material and the nonaqueous electrolyte. This coating suppresses side reactions that cause gas generation while preserving the high discharge capacity of the lithium nickel composite oxide.
Solution Approach 2:
The positive electrode active material is designed as a composite structure combining lithium nickel composite oxide core with alumina shell coating. This composite material approach maintains the high capacity benefits of the lithium nickel composite oxide while the alumina coating provides chemical stability and prevents harmful side reactions with the electrolyte.
2Productivity
If ion migration in electrodes is enhanced, then load characteristics are improved, but side reactions increase
Solution Approach 1:
The alumina coating is applied locally on the surface of each lithium nickel composite oxide particle, creating a localized protective layer that prevents side reactions at the particle-electrolyte interface while maintaining bulk material properties that enable fast ion migration and good load characteristics.
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 configuration improves high-rate discharge performance by reducing the travel distance of lithium ions, minimizing side reactions, and preventing gas generation, resulting in enhanced load characteristics and discharge capacity.
Implementation Method 1
more ion migration in electrodes and improvement in load characteristics are demanded
Implementation Method 2
an average particle size D1 of the positive electrode active material and an average particle size D2 of the inactive particles satisfy D1>D2
Data Source
AI summary
A nonaqueous electrolyte secondary battery includes a positive electrode having a positive electrode mixture layer, a negative electrode, and a nonaqueous electrolyte, wherein the positive electrode mixture layer includes a positive electrode active material and inactive particles, the positive electrode active material includes a lithium-containing composite oxide, an average particle size D1 of the positive electrode active material and an average particle size D2 of the inactive particles satisfy D1>D2, and a viscosity at 30° C. of the nonaqueous electrolyte is less than 2 mPa·s.