Lithium-Ion Cell Recessed Anode Structure for Faster Charging
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Solution Overview
Problem
Lithium-ion secondary batteries face issues of low charging rate and short battery life due to increased polarization during charging and low electrolyte content, which affects mobility of lithium ions and energy density.
Innovation Solution
A cell design with a negative electrode plate featuring a first recess on its surface, optimized dimensions and spacing, and a separator with a ceramic layer, enhancing electrolyte flow and contact area, reducing polarization, and incorporating specific material compositions to improve charging efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the compaction density of the active material layer is increased to increase energy density, then the energy density is improved, but polarization during charging increases resulting in decreased mobility of lithium ions and reduced charging rate
Solution Approach 1:
The negative electrode plate is segmented by forming recesses that divide the active material layer into multiple regions. This segmentation creates multiple electrolyte penetration paths, allowing lithium ions to reach different areas of the active material more efficiently, thereby improving charging rate while maintaining high compaction density
Solution Approach 2:
The recesses formed in the negative electrode plate create a porous structure that facilitates electrolyte penetration. This porous architecture allows better ion transport throughout the electrode, resolving the contradiction between high compaction density and lithium ion mobility by providing channels for ion flow within the dense structure
2Duration of action of stationary object
If the content of electrolyte is increased to improve battery life, then the mobility of lithium ions is improved, but the energy density decreases due to increased volume occupied by electrolyte
Solution Approach 1:
Instead of increasing electrolyte content uniformly throughout the battery volume, the invention introduces electrolyte access in the depth dimension by forming recesses in the electrode plate. This dimensional approach allows better electrolyte distribution and ion mobility without proportionally increasing the overall electrolyte volume, thus maintaining energy density while improving battery life
Data Source
AI summary
The disclosure provides a cell and a lithium-ion secondary battery. The cell includes a positive electrode plate, a separator, and a negative electrode plate. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer, wherein a surface of the negative electrode active material layer is provided with a first recess, the first recess has a depth H in μm, the cell has a length L in mm, and the cell has a width W in mm; and H, L and W satisfy: 0.05H≤L/W≤0.5H.