Lithium-Ion Cell Electrode Layout for Energy Density and Safety
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Solution Overview
Problem
Existing lithium-ion batteries face challenges in achieving high energy density, safety, and cost-effectiveness due to the mismatch between positive and negative electrode materials, particularly with phosphate and ternary materials, which affect the total energy density and capacity performance.
Innovation Solution
The solution involves alternating positive and negative electrode plates in a lithium-ion battery, with each plate having distinct formulations: the positive electrode plates comprising phosphate and high-energy density materials, and the negative electrode plates having different orientations (OI values) to optimize energy density and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphate and ternary materials are mixed internally in a slurry to create a mixed positive electrode, then the energy density can be improved, but the proportion of main material in the electrode plate decreases due to increased requirements for conductive agent and binder
Solution Approach 1:
The patent divides the positive electrode into two separate positive electrode plates instead of mixing phosphate and ternary materials in one electrode. This segmentation allows each electrode plate to use its own optimized material composition without the need for additional conductive agents and binders required for mixed materials, thereby increasing the proportion of main material in each electrode plate while maintaining high energy density through the combination of both electrode types in the battery pack.
2Use of energy by moving object
If phosphate and ternary materials are mixed internally in a slurry to create a mixed positive electrode, then the energy density can be improved, but phosphate materials may adsorb on the surface of ternary materials affecting capacity performance
Solution Approach 1:
The patent separates phosphate and ternary materials into different positive electrode plates, eliminating direct contact between the two material types. This prevents phosphate materials from adsorbing on the surface of ternary materials, thereby preserving the capacity performance of ternary materials while still achieving high energy density through the synergistic combination of both electrode types in the battery pack.
3Use of energy by moving object
If mixed positive electrode materials are used, then the energy density can be improved, but it poses new challenges to the selection of graphite negative electrode materials
Solution Approach 1:
The patent uses two separate positive electrode plates (phosphate and ternary) that can be paired with a single type of graphite negative electrode material. This segmentation approach simplifies the material selection process compared to mixed electrodes, as the graphite material only needs to be compatible with both electrode types rather than requiring complex mixed-material formulations, thereby reducing device complexity while maintaining high energy density.
Data Source
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AI summary
In a cell and an electronic device, a first positive electrode film (5) and a second positive electrode film (4) are respectively arranged on two opposite surfaces of a positive electrode current collector (2). A gram capacity of a second positive electrode active substance is greater than a gram capacity of a first positive electrode active substance. A first negative electrode film (7) and a second negative electrode film (6) are arranged on two opposite surfaces of a negative electrode current collector (1). OI2-OI1>5, where OI2 is an OI value of the second negative electrode film (6), and OI1 is an OI value of the first negative electrode film (7). The positive electrode and the negative electrode in the cell are reasonably matched, which can maximize total energy density and capacity of the cell while also taking safety into account.