Semi-Solid Electrode Coating for Higher-Density Electrochemical Cells
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Solution Overview
Problem
Conventional electrochemical cell manufacturing methods result in batteries with lower energy density, higher inactive material content, and increased complexity due to the need to coat electrodes on both sides of current collectors, leading to longer assembly times and exposure to temperature fluctuations, which degrades electrode materials.
Innovation Solution
The use of semi-solid electrodes coated on only one side of current collectors, with a separator in between, allows for thicker electrodes (up to 2000 μm), higher active material loading, and a simplified manufacturing process, reducing inactive component volume and enhancing electronic conductivity and charge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrodes are coated on both sides of current collectors to increase active material ratio, then the active material to inactive material ratio increases, but the manufacturing complexity and assembly time increase significantly
Solution Approach 1:
The patent applies asymmetry by coating electrodes on only one side of the current collector instead of both sides. This asymmetric configuration simplifies the manufacturing process while maintaining high active material content, as the current collector provides sufficient structural support on one side alone, eliminating the need for symmetric double-sided coating and subsequent complex assembly operations.
Solution Approach 2:
The patent extracts the separator from between individual electrode layers and replaces it with a single protective coating on the current collector. This removal of the separator simplifies the overall structure, reduces the number of components, and eliminates the complex stacking and alignment operations required in conventional multi-layer assemblies.
2Manufacturing precision
If conventional coating methods are used to achieve thin electrodes, then manufacturing precision is maintained, but energy density and capacity are limited
Solution Approach 1:
The patent changes the electrode thickness parameter from conventional thin electrodes (<100 μm) to thick electrodes (≥250 μm, up to 2000 μm). This parameter change is enabled by the one-sided coating configuration and protective coating approach, which maintain manufacturing precision while allowing significantly increased active material volume and energy density.
Solution Approach 2:
The patent transitions from two-dimensional thin electrode surfaces to three-dimensional thick electrode structures. By coating on only one side and allowing substantial thickness buildup, the design exploits the third dimension (depth/thickness) to increase active material volume without proportionally increasing the footprint area, thereby enhancing energy density.
3Loss of time
If assembly time is reduced by simplifying the process, then exposure to temperature fluctuations decreases, but manufacturing precision may be compromised
Solution Approach 1:
The patent applies preliminary action by forming a protective coating on the current collector before electrode assembly. This pre-formed protective layer is applied during the coating process itself, protecting the electrode from environmental degradation during subsequent handling and assembly operations, thereby maintaining manufacturing precision even with reduced assembly time.
Solution Approach 2:
The patent skips the intermediate step of using separators between electrodes by directly assembling coated current collectors. This eliminates the time-consuming separator insertion and alignment steps while the protective coating continues to provide environmental protection, thus reducing assembly time without compromising electrode quality.
Data Source
AI summary
Embodiments described herein relate generally to electrochemical cells having semi-solid electrodes that are coated on only one side of a current collector. In some embodiments, an electrochemical cell includes a semi-solid positive electrode coated on only one side of a positive current collector and a semi-solid negative electrode coated on only one side of a negative current collector. A separator is disposed between the semi-solid positive electrode and the semi-solid negative electrode. At least one of the semi-solid positive electrode and the semi-solid negative electrode can have a thickness of at least about 250 μm.