Secondary Battery Electrode Depression Formation
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Solution Overview
Problem
Conventional methods for forming high-aspect-ratio depressions in secondary battery electrode active material layers face challenges in maintaining capacity while facilitating charge carrier diffusion to the electrode current collector, as the electrode active material is compressed and densified during relief pattern transfer, making it difficult to achieve high-aspect-ratio features.
Innovation Solution
A method involving the preparation of a moisture powder with a pendular or funicular state, forming a coating film on an electrode current collector, and using a die with varying elevations to create and deepen depressions, allowing for the production of secondary battery electrodes with high-aspect-ratio depressions without significant densification, thereby enhancing charge carrier diffusion while minimizing capacity decline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If relief pattern transfer is performed using conventional methods, then the electrode active material layer is compressed and densified, but it becomes difficult to form high-aspect-ratio depressions
Solution Approach 1:
The patent applies preliminary action by forming a depression with a first die having a prescribed elevation height before performing relief pattern transfer. This pre-formed depression serves as a foundation that allows the relief pattern to be transferred without requiring excessive compression that would otherwise be needed, thereby enabling high-aspect-ratio depression formation while simplifying the overall manufacturing process
Solution Approach 2:
The patent segments the depression formation process into two distinct steps: first forming a depression using a die with prescribed elevation, then performing relief pattern transfer. This segmentation allows each step to be optimized independently, achieving high-aspect-ratio depressions without the need for excessive compression that would complicate the manufacturing process
2Reliability
If a depression is placed in the electrode active material layer, then charge carrier diffusion to the current collector is facilitated, but the capacity declines due to absence of electrode active material
Solution Approach 1:
The patent applies parameter changes by controlling the depth and aspect ratio of the depression to be less than or equal to 0.5 times the coating film thickness. This parameter control ensures that the depression is sufficient to facilitate charge carrier diffusion to the current collector, while simultaneously maintaining enough electrode active material in the region to preserve capacity
3Stability of the object's composition
If the electrode active material layer is compressed and densified during relief pattern transfer, then the structure is stabilized, but high-aspect-ratio depressions cannot be formed
Solution Approach 1:
The patent performs preliminary depression formation before relief pattern transfer, creating a stable structural foundation first. This allows the subsequent relief pattern transfer to occur on an already-stabilized structure, preventing the need for excessive compression that would otherwise be required to create deep depressions, thereby preserving both structural stability and depression geometry
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 method enables the production of secondary battery electrodes with high-aspect-ratio depressions, facilitating charge carrier diffusion to the electrode current collector while maintaining or improving capacity, allowing for efficient energy storage and transfer.
Implementation Method 1
a step of forming, using this moisture powder, a coating film composed of the moisture powder, on an electrode current collector, while the gas phase remains present
Implementation Method 2
a step of forming a depression in the coating film by carrying out, using a die having an elevation of prescribed height, depression/elevation transfer into a surface region of the coating film
Implementation Method 3
a step of carrying out depression/elevation transfer, using a die having an elevation higher than the elevation of prescribed height, by pressing the higher elevation into the depression that has been formed
Implementation Method 4
a step of forming an electrode active material layer by removing the solvent
Data Source
AI summary
A method for producing secondary battery electrodes includes a step of preparing a moisture powder formed of aggregated particles that contain a plurality of electrode active material particles, a binder resin, and solvent, wherein the solid phase, liquid phase, and gas phase in at least 50 number % or more of the aggregated particles in the moisture powder form a pendular state or a funicular state; a step of forming a coating film composed of the moisture powder on an electrode current collector, while the gas phase remains present; a step of forming a depression in the coating film by carrying out, using a die having an elevation of prescribed height, depression/elevation transfer into the coating film; and a step of carrying out depression/elevation transfer, using a die having an elevation higher than the elevation of prescribed height, by pressing the higher elevation into the depression that has been formed.