Positive Electrode Plate With Al Gradient for High-Temperature Cycling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing demand for higher energy density in lithium-ion batteries leads to a decrease in structural stability of lithium cobalt oxide in positive electrode plates, resulting in deterioration of high-temperature cycling performance.
Innovation Solution
A positive electrode plate design with varying aluminum content in lithium cobalt oxide particles across different thickness layers, where the content is higher in the top layer and lower in the bottom layer, improving stability and high-temperature performance by optimizing the distribution of aluminum in the active material layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the specific capacity per gram of the positive electrode active material is increased to improve energy density, then the energy density of the lithium-ion battery is improved, but the structural stability of lithium cobalt oxide decreases, resulting in deterioration of high temperature cycling performance
Solution Approach 1:
The patent applies local quality by creating a positive electrode plate with non-uniform aluminum content distribution. The aluminum content is higher in regions where lithium cobalt oxide is present and lower or absent in regions without lithium cobalt oxide. This localized modification stabilizes the lithium cobalt oxide structure in specific areas without compromising the overall energy density of the electrode, thereby resolving the contradiction between energy density and structural stability.
Solution Approach 2:
The patent changes the chemical composition parameter by introducing aluminum elements into the lithium cobalt oxide structure. This parameter change (adding aluminum doping) modifies the crystal structure stability of lithium cobalt oxide, allowing it to maintain structural integrity even at higher specific capacities. The aluminum content is carefully controlled to balance structural stabilization with energy density requirements.
2Quantity of substance
If more lithium is deintercalated from lithium cobalt oxide to increase specific capacity, then the energy density is improved, but the structural stability of lithium cobalt oxide decreases, causing deterioration of high temperature cycling
Solution Approach 1:
The patent applies local quality by concentrating aluminum stabilization in specific regions of the positive electrode where lithium cobalt oxide is located. The aluminum content is locally optimized to prevent structural degradation during lithium deintercalation cycles at high temperatures, while other regions of the electrode can maintain higher lithium content to preserve energy density.
Solution Approach 2:
The patent applies beforehand cushioning by pre-introducing aluminum elements into the lithium cobalt oxide structure before battery operation. This aluminum doping acts as a preventive measure that cushions against structural degradation that would otherwise occur during repeated lithium deintercalation and reintercalation cycles, particularly at elevated temperatures. The aluminum framework is established in advance to protect the lithium cobalt oxide structure during cycling.
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 design enhances the structural stability and cycling performance of lithium-ion batteries by balancing lithium deintercalation and intercalation, maintaining high energy density and long cycle life.
Implementation Method 1
making more lithium deintercalated from lithium cobalt oxide in the positive electrode plate
Implementation Method 2
balancing lithium deintercalation and intercalation
Data Source
AI summary
Disclosed are a positive electrode plate and a battery. A relationship is established between a thickness of an electrode plate, distribution of lithium cobalt oxide with a structure of different contents of element aluminum, and full battery cycling performance. That is, based on a thickness of the electrode plate, lithium cobalt oxide with an appropriate content of the element aluminum is selected, and distribution in a thickness direction of the positive electrode plate is changed, so that the content of Al in the thickness direction of the electrode plate generally presents a distribution trend of less content of Al in a bottom layer and more content of Al in a top layer. In this way, a problem of deterioration of high temperature cycling of a lithium-ion battery due to decreased structural stability of existing lithium cobalt oxide may be solved.