Lithium Nickel Cathode Powder Composition for Lower Battery Resistance
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Solution Overview
Problem
Lithium ion batteries face increased resistance due to the generation of new surfaces when positive electrode active materials are crushed, which counteracts the intended reduction in resistance from increased reaction area.
Innovation Solution
A positive electrode active material with lithium nickel composite oxide powder is developed, where the D50 is 2.7 μm or less and the dR2 ratio is between 0.1 and 0.4, and the Ni ratio is 0.5 or more, with specific composition and crushing in an inert gas atmosphere to minimize resistance component generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the positive electrode active material is crushed to increase specific surface area, then the reaction area is increased, but new surfaces are generated that create resistance components
Solution Approach 1:
The patent applies parameter changes by precisely controlling particle size (D50 ≤ 2.7 μm) and the dR2 ratio (0.1 ≤ dR2 ≤ 0.4) to optimize the balance between reaction area and resistance component generation. This quantitative parameter control resolves the contradiction by finding the optimal range where increased surface area does not proportionally increase resistance.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel composite oxide with specific ratios of Ni (0.5 or more), Co, Mn, and doping elements (Al, Ti, Zr, Mo, W, Mg, Ca, Na, Fe, Cr, Zn, Si, Sn, B, Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu, Hf, Ta, Re, Pt, Pd, Ag, In, Ga, Ge, Se, Te). This composite structure modifies surface properties to reduce resistance component generation while maintaining high reaction area.
2Quantity of substance
If high nickel material is used to achieve high capacity, then the capacity is improved, but resistance component generation increases when crushed
Solution Approach 1:
The patent applies local quality by using doping elements (Al, Ti, Zr, Mo, W, Mg, Ca, Na, Fe, Cr, Zn, Si, Sn, B, Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu, Hf, Ta, Re, Pt, Pd, Ag, In, Ga, Ge, Se, Te) at specific sites within the lithium nickel composite oxide structure. These dopants locally modify the material properties at particle surfaces and interfaces, reducing resistance component generation in high nickel materials while preserving bulk capacity.
Solution Approach 2:
The patent combines high nickel content (0.5 or more) with multiple other elements (Co, Mn, and doping elements) to create a composite material structure. This composite approach allows the material to achieve high capacity from the nickel content while the other elements suppress resistance component generation, particularly at particle surfaces generated during crushing.
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 reduces battery resistance by balancing the increased reaction area with minimized resistance component generation, enhancing battery performance.
Implementation Method 1
R represents a ratio of a height of a second peak with respect to a height of a first peak in an absorption spectrum of oxygen by X-ray absorption fine structure spectroscopy
Data Source
AI summary
The positive electrode active material includes a lithium nickel composite oxide powder. The positive electrode active material has a relationship of the formula (1) “0.1≤d×R×≤0.4” and the formula (2) “d≤2.7”. In formulae (1) and (2), d has units of μm. d represents D50 of the lithium nickel composite oxide powder. R is a dimensionless quantity. R represents a ratio of a height of a second peak with respect to a height of a first peak in an absorption spectrum of oxygen by X-ray absorption fine structure spectroscopy. The first peak has a peak top within 529 eV to 530 eV. The second peak has a peak top within 533 eV to 534 eV.