Stacked Electrode Assembly With Low-Curl Outer Negative Electrode
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Solution Overview
Problem
The curling phenomenon of electrodes with active material layers on one surface during manufacturing poses challenges in transportation and alignment, reducing the manufacturing yield of stacked electrode assemblies in rechargeable batteries.
Innovation Solution
The electrode assembly design includes a second negative electrode with a higher silicon-based active material content and thinner active material layer on the inner surface, paired with a substrate of equal or slightly greater thickness, reducing the elongation rate difference and minimizing curling, while maintaining or enhancing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an active material layer is disposed on only one surface of the substrate in the outermost electrode, then the capacity within limited size and thickness is maximized, but a curling phenomenon occurs due to difference in elongation rate between substrate and active material layer
Solution Approach 1:
The patent changes the material composition parameter of the active material layer by incorporating silicon-based active material (5-50 wt%) in addition to carbon-based active material. This compositional change modifies the elongation characteristics of the active material layer, reducing the elongation rate difference between the substrate and active material layer, thereby suppressing the curling phenomenon while maintaining high capacity
Solution Approach 2:
The patent uses a composite active material layer consisting of carbon-based active material and silicon-based active material. The silicon-based active material has different mechanical properties compared to carbon-based materials, and its incorporation creates a composite structure that balances the elongation characteristics between the substrate and active material layer, preventing curling while enhancing capacity
2Ease of manufacture
If an active material layer is disposed on only one surface of the substrate, then the electrode structure is simplified for manufacturing, but the electrode becomes challenging to transport and align
Solution Approach 1:
By changing the material composition parameter to include silicon-based active material, the patent modifies the mechanical properties of the active material layer, specifically reducing the elongation rate difference with the substrate. This parameter change suppresses curling during manufacturing, resulting in flat electrodes that are easier to transport and align, thereby improving ease of operation without complicating the manufacturing process
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 design effectively suppresses curling, facilitates easier transportation and alignment, and increases manufacturing yield, while maintaining or improving capacity and volume stability through the use of a high-strength can.
Implementation Method 1
a curling phenomenon may occur in which the electrode bends due to a difference in elongation rate between the substrate and the active material layer
Data Source
AI summary
An electrode assembly includes a plurality of positive electrodes and a plurality of negative electrodes alternately stacked. The plurality of negative electrodes include a plurality of first negative electrodes and at least one second negative electrode located outside of the plurality of first negative electrodes. At least one of the plurality of first negative electrodes includes a first substrate and first active material layers on both surfaces of the first substrate. The second negative electrode includes a second substrate and a second active material layer on one surface of the second substrate. A content of a silicon-based active material in the second active material layer is higher than a content of a silicon-based active material in the first active material layer.