Functional Electrode Assembly for Safer High-Capacity Li-Ion Batteries
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Solution Overview
Problem
Rechargeable lithium batteries used in vehicles face safety concerns due to heat dissipation issues when increased in thickness or size to achieve higher capacity, necessitating a solution that enhances safety while maintaining high energy density and cycle-life characteristics.
Innovation Solution
The electrode assembly incorporates a functional unit cell structure with a first and second functional layer, each with active materials having lower reference potentials than the positive active material, strategically positioned to prevent side reactions and heat generation, thereby improving safety and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness and size of the rechargeable lithium battery are increased to achieve high capacity, then the energy density is improved, but the safety deteriorates due to heat dissipation difference inside/outside of the battery
Solution Approach 1:
The battery is divided into multiple unit cells (first, second, and third unit cells) arranged in a segmented structure. The third unit cell is positioned at the center in the thickness direction, surrounded by the first and second unit cells. This segmentation allows for better heat distribution and dissipation throughout the battery structure, preventing localized overheating while maintaining high capacity through the increased number of cells.
Solution Approach 2:
Different unit cells are assigned different functions based on their positions. The third unit cell at the center serves as a heat dissipation core, while the first and second unit cells at the outer sides provide additional capacity. This local differentiation optimizes both safety (through centralized heat management) and capacity (through distributed energy storage).
2Quantity of substance
If the thickness of the rechargeable lithium battery is increased to achieve high capacity, then the energy density is improved, but the heat dissipation capability deteriorates
Solution Approach 1:
The battery structure is segmented into multiple unit cells with the third unit cell positioned at the center in the thickness direction. This segmentation creates multiple heat generation and dissipation zones, preventing heat accumulation in a single location and improving overall thermal management while maintaining high capacity through the combined energy storage of all cells.
Solution Approach 2:
The unit cells are arranged in a multi-dimensional configuration rather than a simple linear stack. By positioning the third unit cell at the center in the thickness direction and surrounding it with first and second unit cells, the structure creates a three-dimensional heat distribution network that enhances heat dissipation efficiency while preserving capacity.
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 electrode assembly effectively enhances safety and cycle-life characteristics of rechargeable batteries by reducing side reactions and heat generation, ensuring reliable performance and capacity retention, as demonstrated in experimental examples.
Implementation Method 1
a functional layer, and a third unit cell. The first unit cell includes a positive electrode and a negative electrode. The positive electrode includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector and including a positive active material
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
Disclosed is that an electrode assembly and a rechargeable battery including the same, and the electrode assembly includes a plurality of unit cells overlapping in a thickness direction, a first functional unit cell disposed at an outermost first surface of the plurality of unit cells and a second functional unit cell at an outermost second surface that is opposed to the first surface, wherein each of the first functional unit cell and the second functional unit cell include an outer unit cell including a negative electrode, a positive electrode and a separator disposed between the negative electrode and the positive electrode, the positive electrode includes a positive current collector, a positive active material layer disposed on at least one surface of the positive current collector and including a positive active material having a first reference potential, and a first functional layer disposed on the positive active material layer and including a first active material having a lower second reference potential than the first reference potential.