Secondary Battery Electrode Grooving With Wet Coating Film Release
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for forming grooves of different depths and extending in two directions in the electrode active material layer of secondary battery electrodes often result in defects due to die release issues.
Innovation Solution
A method involving the use of a moisture powder with a pendular or funicular state, formed by aggregated particles containing electrode active material, binder resin, and solvent, is applied to an electrode current collector. This method includes forming a coating film, creating first and second grooves using roll dies, and removing the solvent to form the electrode active material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If grooves of different depths and extending in two directions are formed in the electrode active material layer using a relief pattern-bearing die, then the electrode structure is improved for stress relaxation, but die release defects occur readily
Solution Approach 1:
The patent applies preliminary action by forming grooves in the coating film before the electrode active material layer is fully dried. The coating film is formed with grooves while still containing solvent, which acts as a release agent preventing die attachment, and then the layer is dried to form the final electrode structure with grooves
Solution Approach 2:
The patent uses the solvent in the coating film as an intermediary substance that prevents direct attachment between the electrode active material layer and the relief pattern-bearing die. The solvent acts as a temporary release agent during the groove formation process, allowing the die to be removed without causing defects
2Stability of the object's composition
If the electrode active material layer is formed by coating and drying, then a uniform layer is obtained, but grooves cannot be formed to relax expansion stresses
Solution Approach 1:
The patent segments the process into two distinct stages: first forming a uniform coating film with solvent, then forming grooves in this film before final drying. This segmentation allows the coating to maintain uniformity while acquiring the groove structure for stress relaxation in the final dried state
Solution Approach 2:
The groove formation is performed as a preliminary action on the wet coating film before the electrode active material layer is fully dried. This timing allows the grooves to be formed when the material is still pliable and contains solvent, preventing die attachment while ensuring the grooves are present in the final dried structure
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 method effectively produces secondary battery electrodes with grooves of varying depths and orientations while minimizing die release defects, enhancing the electrode's performance and manufacturing efficiency.
Implementation Method 1
a 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
Implementation Method 2
a 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
Implementation Method 3
a 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
Implementation Method 4
forming, in the coating film, a first groove that extends in a first direction, by transferring depressions and elevations, using a first roll die, into a surface region of the coating film
Implementation Method 5
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 electrode active material particles, a binder resin, and solvent, wherein the solid phase, liquid phase, and gas phase in at least 50 number % of the aggregated particles form a pendular state or a funicular state; a step of forming, using the moisture powder, a coating film while the gas phase remains present; a step of forming a first groove that extends in a first direction, by transferring depressions and elevations, using a first roll die, into the coating film; and a step of forming a second groove that extends in a different direction, by transferring depressions and elevations, using a second roll die, into the coating film. Depression/elevation transfer is carried out in such a manner that the second groove is made deeper than the first groove.