Nonaqueous Battery Electrode Capacity Ratio and Composition
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Solution Overview
Problem
Nonaqueous electrolyte batteries with an excessive positive electrode capacity relative to the negative electrode capacity experience structural deterioration of the positive electrode active material due to over-discharge and increased operating voltage, leading to decreased input and output characteristics.
Innovation Solution
The use of a nickel-cobalt-manganese composite oxide (Li1-aNixCoyMnzO2) as the positive electrode material, with a specific composition and surface treatment to maintain a lower valence state and prevent over-discharge, combined with a titanium oxide negative electrode, sets the capacity ratio of the positive to negative electrode within 1.2 to 2, reducing the average operating voltage and suppressing structural deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the positive electrode capacity is set to be excessive relative to the negative electrode capacity, then the battery can operate at higher voltage and deliver more power, but the positive electrode active material undergoes structural deterioration due to over-discharge
Solution Approach 1:
The patent applies parameter changes by precisely controlling the capacity ratio between positive and negative electrodes to fall within 1.05 to 1.30, and by controlling the content of nickel-cobalt-manganese composite oxide in the positive electrode active material within 80 to 95 mass%. These parameter optimizations allow the battery to achieve high power output while preventing structural deterioration of the positive electrode during over-discharge cycles
Solution Approach 2:
The patent uses composite materials by formulating the positive electrode active material as a composite of nickel-cobalt-manganese composite oxide combined with other lithium-containing compounds. This composite structure enhances the structural stability of the positive electrode while maintaining high capacity, allowing the battery to operate reliably at excessive capacity ratios without suffering from over-discharge damage
2Power
If the positive electrode capacity is set to be excessive relative to the negative electrode capacity, then the battery can deliver higher power, but the electrical resistance of the positive electrode increases
Solution Approach 1:
The patent applies parameter changes by optimizing the composition ratios of the nickel-cobalt-manganese composite oxide and controlling its content within 80 to 95 mass% of the total positive electrode active material. This parameter optimization ensures that the positive electrode maintains low electrical resistance even when operating at excessive capacity ratios, thereby preserving high power output characteristics
3Power
If the positive electrode capacity is set to be excessive relative to the negative electrode capacity, then the battery can operate at higher voltage, but the average operating voltage increases leading to reduced efficiency
Solution Approach 1:
The patent applies parameter changes by precisely controlling the capacity ratio between positive and negative electrodes to fall within 1.05 to 1.30, and by optimizing the composition and content of nickel-cobalt-manganese composite oxide in the positive electrode. These parameter optimizations enable the battery to achieve high voltage output while maintaining efficient energy utilization and minimizing energy losses during operation
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 enhances the cycle life and maintains low average operating voltage while preventing the increase in electrical resistance of the positive electrode, thereby improving the battery's input and output characteristics.
Implementation Method 1
a ratio AS/A Ni of an S atom abundance ratio AS to an Ni atom abundance ratio A Ni obtained by subjecting a surface of the positive electrode to a photoelectron spectroscopic measurement
Implementation Method 2
The negative electrode includes an oxide of titanium. The positive electrode includes a nickel-cobalt-manganese composite oxide
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
According to one embodiment, there is provided a nonaqueous electrolyte battery (100). The nonaqueous electrolyte battery (100) includes a negative electrode (2), a positive electrode (3), and a nonaqueous electrolyte. The positive electrode (3) includes a nickelcobalt-manganese composite oxide represented by a composition formula Li1-aNixCoyMnzO2. Subscripts x, y, and z satisfy an inequality 0.1 ≤ x/(y + z) ≤ 1.3, and subscript a satisfies 0 ≤ a ≤ 1. A ratio AS/ANi of an S atom abundance ratio As to an Ni atom abundance ratio ANi of a surface of the positive electrode (3) is 0.4 to 5. A ratio p/n of a capacity p of the positive electrode (3) to a capacity n of the negative electrode (2) is within a range of 1.2 to 2.