Positive Electrode Material Density Optimization
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in achieving high energy density and high output characteristics due to insufficient electrode density.
Innovation Solution
A positive electrode material with a specific ratio of oil absorption amount to void volume and adjusted powder density is developed, improving wettability and allowing for uniform electrode paste preparation, which enhances electrode density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the electrode density is increased to improve energy density and high output characteristics, then the energy density and output characteristics are improved, but the coating properties and uniformity of electrode paste preparation deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the oil absorption amount to be within a specific range (30-50 mL/100g) and controlling the void volume to achieve a specific ratio relationship. This parameter optimization enables the powder to have both good wettability for uniform coating and sufficient density for high energy density, resolving the contradiction between coating properties and electrode density
Solution Approach 2:
The patent utilizes the void volume within the positive electrode material particles as a controlled porous structure. By maintaining an appropriate void volume and optimizing its ratio to oil absorption amount, the material achieves good solvent penetration and uniform paste preparation while maintaining high density, thus improving both coating properties and electrode density simultaneously
2Ease of manufacture
If the oil absorption amount is increased to improve wettability and coating properties, then the coating properties are improved, but the electrode density deteriorates
Solution Approach 1:
The patent optimizes the oil absorption amount to a specific range (30-50 mL/100g) and controls the void volume to achieve an optimal ratio (0.30-0.85). This parameter optimization ensures that the material has sufficient wettability for good coating properties while avoiding excessive oil absorption that would reduce electrode density, thus resolving the contradiction between these two parameters
3Volume of stationary object
If the powder density is increased to improve electrode density, then the electrode density is improved, but the wettability and uniformity of paste preparation deteriorate
Solution Approach 1:
The patent utilizes controlled void volumes within the powder particles to maintain wettability. By optimizing the void volume and its ratio to oil absorption amount, the material allows sufficient solvent penetration and binder distribution while maintaining high powder density, thus achieving both good wettability and high electrode density
Solution Approach 2:
The patent optimizes the ratio of oil absorption amount to void volume within a specific range (0.30-0.85) to achieve the best balance between wettability and density. This parameter optimization ensures that high powder density does not compromise wettability, as the controlled void structure allows proper paste preparation uniformity
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 results in improved energy density and high output characteristics for lithium ion secondary batteries by ensuring a sufficient electrode density during pressing.
Implementation Method 1
since a ratio between an oil absorption amount per unit mass and a void volume per unit mass correlates to wettability of powder
Data Source
Figure 1~2
AI summary
A positive electrode material for lithium ion secondary batteries is provided, wherein a ratio (A/B) of an oil absorption amount (A) of powder per unit mass of the material, which is measured using N-methyl-2-pyrrolidone, to a void volume (B) of powder per unit mass of the material is 0.30 or more and 0.85 or less, and a ratio (C/D) of a powder density (C) of the material, which is measured in a powder pressure test at a pressure of 4.5 MPa, to an initial powder density (D) of the material is 1.3 or more and 1.7 or less.