Electrode Stack Assembly with Surface-Treated Separators
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Solution Overview
Problem
Current energy storage device manufacturing processes face challenges in achieving strong and durable electrode stacks with efficient binding between electrodes and current collector films, often resulting in poor adhesion and increased resistance.
Innovation Solution
The method involves surface treating the cell separator and electrodes to create binding sites, followed by cold press lamination, and depositing electrode slurry on a sacrificial film with a current collector film attachment, ensuring higher binding strength to the current collector than to the sacrificial film, allowing for delamination while maintaining attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional manufacturing processes are used for electrode stacks, then production is simpler, but adhesion between electrodes and current collector films is poor and resistance is increased
Solution Approach 1:
The patent applies preliminary surface treatment to the cell separator before assembly to create binding sites that will enhance adhesion during cold press lamination. This preliminary action ensures strong binding between electrodes and current collector films before the actual assembly process begins, resolving the adhesion problem without requiring complex post-processing steps.
Solution Approach 2:
The patent introduces a sacrificial film as an intermediary medium during the electrode deposition process. The electrode slurry is deposited on the sacrificial film first, then the current collector film is attached, and finally the sacrificial film is delaminated. This intermediary approach enables controlled binding strength differentiation, ensuring strong adhesion to the current collector while allowing easy removal of the sacrificial film.
2Reliability
If surface treatment is applied to create binding sites, then adhesion is improved, but manufacturing steps are increased
Solution Approach 1:
The patent combines multiple functions into the cold press lamination step: it simultaneously laminates the electrodes to the current collector films and activates the binding sites on the cell separator surface. This merging of operations improves binding strength without proportionally increasing manufacturing steps, as the surface treatment is performed separately but the lamination process achieves dual objectives.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the cell separator surface through surface treatment to create binding sites with enhanced electrostatic stabilization. By changing the surface properties (creating binding sites) rather than changing the bulk material properties, the patent achieves improved binding strength with minimal impact on manufacturing efficiency, as only the surface layer is modified.
3Strength
If cold press lamination is used with surface treated separators, then adhesion is enhanced, but process time is increased
Solution Approach 1:
The surface treatment of the cell separator is performed as a preliminary step before assembly, creating binding sites that will be activated during cold press lamination. This preliminary preparation ensures that the lamination process itself is more efficient and requires less time to achieve strong adhesion, as the binding sites are already in place and only need to be activated by the lamination pressure and temperature.
4Reliability
If electrode slurry is deposited on sacrificial film, then binding strength to current collector is improved, but delamination step is added
Solution Approach 1:
The sacrificial film serves as an intermediary substrate that enables controlled binding strength differentiation. The electrode slurry is deposited on the sacrificial film first, then the current collector film is attached, creating a hierarchy of binding strengths. The sacrificial film is designed to have weaker binding to the electrode than the current collector film does, allowing selective delamination. This intermediary approach adds only one delamination step while significantly improving binding strength reliability.
Solution Approach 2:
The sacrificial film is designed to be temporarily used and then discarded (delaminated and removed) after serving its purpose of enabling controlled binding strength development. This temporary use of a disposable component allows the main structure (electrode-current collector bond) to achieve optimal strength without requiring complex reversible bonding mechanisms.
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 approach results in flexible and durable electrode stacks with improved adhesion, reduced resistance, and enhanced performance in energy storage devices, particularly suitable for lithium-ion batteries with improved charging and discharging rates.
Implementation Method 1
surface treating is configured to form binding sites on the cell separator and enhance binding thereof to the at least one electrode by creating the binding sites
Implementation Method 2
attaching the at least one cell separator to the at least one electrode by cold press lamination
Implementation Method 3
depositing an electrode slurry on a sacrificial film to form an electrode thereupon
Data Source
AI summary
Methods, stacks and electrochemical cells are provided, in which the cell separator is surface-treated prior to attachment to the electrode(s) to form binding sites on the cell separator and enhance binding thereof to the electrode(s), e.g., electrostatically. The cell separator(s) may be attached to the electrode(s) by cold press lamination, wherein the created binding sites are configured to stabilize the cold press lamination electrostatically—forming flexible and durable electrode stacks. Electrode slurry may be deposited on a sacrificial film and then attached to current collector films, avoiding unwanted interactions between materials and in particular solvents involved in the respective slurries. Dried electrode slurry layers may be pressed or calendared against each other to yield thinner, smother and more controllably porous electrodes, as well as higher throughput. The produced stacks may be used in electrochemical cells and in any other type of energy storage device.