Roll Pressing Buffer Structure for Solid-State Battery Interfaces
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Solution Overview
Problem
Existing techniques face challenges in reducing interfacial resistance between the solid electrolyte layer and the electrode in all-solid-state battery manufacturing, particularly in efficiently transferring fine recesses and projections onto the roll surface during roll pressing.
Innovation Solution
A pressing apparatus and method utilizing buffer members with recesses or projections to compress the laminate, ensuring uniform compressive force and transferring these features onto the electrodes, thereby increasing the contact area between the electrodes and the solid electrolyte layer, enhancing adhesion and bondability while reducing DCR resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a buffer film is interposed on the contact surface during roll pressing, then the pressing intensity becomes appropriate and the pressing becomes uniform in the in-plane direction, but it is difficult to further lower interfacial resistance between the solid electrolyte layer and the electrode
Solution Approach 1:
The buffer member is designed with an asymmetric surface structure where one surface has recesses and projections (first surface) while the other surface is flat (second surface). This local quality differentiation allows the recesses and projections to concentrate pressing force at specific contact points, increasing contact area and reducing interfacial resistance, while the flat surface ensures uniform pressing distribution across the electrode.
Solution Approach 2:
The buffer member with pre-formed recesses and projections is positioned between the roll and the electrode before pressing begins. This preliminary configuration ensures that the pressing force is immediately distributed through the asymmetric surface structure, creating optimal contact conditions from the start of the pressing process and effectively reducing interfacial resistance.
2Quantity of substance
If fine recesses and projections are provided on the roll surface to improve filling density, then the filling density of active material increases, but it is difficult to provide fine recesses and projections on the roll surface
Solution Approach 1:
Instead of directly forming fine recesses and projections on the roll surface, a buffer member with pre-formed asymmetric recesses and projections is introduced as an intermediary between the roll and the electrode. This buffer member transfers the pressing force with enhanced contact area while avoiding the manufacturing complexity of creating fine surface features directly on the roll.
Solution Approach 2:
The pressing system is segmented into three distinct components: the roll, the buffer member with asymmetric surface structure, and the electrode. This segmentation allows the buffer member to specialize in providing the recesses and projections for improved contact, while the roll maintains its simple cylindrical structure for easy manufacturing.
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 solution enables the production of high-performance batteries with low DCR resistance and high charge/discharge efficiency by uniformly transferring recesses and projections onto the electrodes, improving the interface contact area and manufacturing efficiency.
Implementation Method 1
a compression unit that compresses the laminate, the compression unit being configured to compress the laminate with buffer members interposed, the buffer members having recesses or projections on surfaces adjacent to the laminate
Data Source
AI summary
Provided are a pressing apparatus and a pressing method capable of lowering interfacial resistance between solid electrolyte layers and electrodes with a simple configuration. A pressing apparatus presses a laminate including electrodes (a positive current collecting electrode and a negative current collecting electrode) and solid electrolyte layers, the pressing apparatus including a compression unit (a roll pressing machine) that compresses the laminate, the compression unit being configured to compress the laminate with buffer members interposed having recesses or projections on surfaces adjacent to the laminate. In an aspect, the compression unit compresses the laminate including the negative electrode (the negative current collecting electrode) containing lithium. In an aspect, the compression unit is a roll pressing machine.