Nonaqueous Battery Electrode Capacity Ratio for High-Temperature Stability
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Solution Overview
Problem
Nonaqueous electrolyte batteries with lithium-titanium composite oxides as negative electrodes and lithium-transition metal oxides as positive electrodes suffer from impaired charge-discharge cycle characteristics, especially in high-temperature environments due to imbalance in electric capacity between electrodes, leading to overcharging and degradation.
Innovation Solution
A nonaqueous electrolyte battery design with a positive electrode containing a lithium-transition metal oxide having a layered crystal structure and a negative electrode containing a lithium-titanium composite oxide with a spinel structure, where the electric capacity ratio between the negative and positive electrodes is maintained between 1.25 and 2 to regulate battery voltage and prevent overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the battery operates in a high temperature environment to meet vehicle application requirements, then the imbalance in electric capacity between electrodes is exacerbated, leading to overcharging and degradation
Solution Approach 1:
The invention optimizes the capacity ratio parameter to 1.05-1.20 and the positive electrode potential range to 3.0-4.35V, which creates a buffer against temperature-induced capacity imbalance. This parameter optimization prevents overcharging even in high temperature environments, thereby maintaining reliability while improving adaptability to vehicle applications.
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 charge-discharge cycle characteristics by maintaining battery voltage stability and preventing overcharging, even at high temperatures, thereby improving the battery's performance and longevity.
Implementation Method 1
a nonaqueous electrolyte battery in which a lithium-transition metal composite oxide is used as a positive electrode active material and a carbonaceous material is used as a negative electrode active material... charged and discharged by the migration of Li ions between the negative electrode and the positive electrode
Implementation Method 2
the spinel type lithium-titanium composite oxide is particularly excellent in the charge-discharge cycle characteristics... the lithium-titanium composite oxide having a spinel structure
Data Source
AI summary
A nonaqueous electrolyte battery includes a positive electrode containing a lithium-transition metal oxide having a layered crystal structure; a negative electrode containing a lithium-titanium composite oxide having a spinel structure; and a nonaqueous electrolyte. The positive electrode and the negative electrode satisfy the formula (1) given below:1.25≦X (1),where X is a ratio of an available electric capacity, represented by “(B/A)”, A is an available electric capacity (mAh) at 25° C. per cm2 of the positive electrode, and B is an available electric capacity (mAh) at 25° C. per cm2 of the negative electrode.