Solid-State Battery Tab Stress Relaxation
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Solution Overview
Problem
Solid-state batteries face issues with cracking of electrode active material and delamination within or between layers due to bending stress generated during the convergence of current collector tabs during manufacturing.
Innovation Solution
Incorporating a stress relaxation section with a wave shape, such as triangular, saw, rectangular, or sinusoidal, in the current collector tab at the bending region to alleviate bending stress, which can be thinner than other portions to facilitate bending and stress relief.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current collector tabs are converged and bound together during manufacturing, then electrical connection is established, but bending stress causes cracks in electrode active material and delamination
Solution Approach 1:
The current collector tab is designed with a curved bending region instead of a straight shape. This curvature allows the tab to flex and absorb bending stress during convergence, preventing stress concentration that would cause cracks in the electrode active material and delamination, while still maintaining effective electrical connection.
Solution Approach 2:
The thickness of the current collector tab is varied along its length, with the bending region having a different thickness parameter than the straight portions. This parameter change enables the bending region to be more flexible and stress-resistant, allowing safe convergence of multiple tabs without compromising electrode integrity.
2Strength
If current collector tabs are made thicker for strength, then structural integrity improves, but bending stress during convergence increases causing cracks and delamination
Solution Approach 1:
The current collector tab exhibits non-uniform thickness distribution, with thicker straight portions providing structural strength and a thinner curved bending region reducing bending stress. This local quality variation allows the tab to maintain overall strength while minimizing stress during convergence operations.
Solution Approach 2:
The curved bending region geometry inherently reduces bending stress compared to a straight configuration. The curvature distributes stress more evenly throughout the material, preventing concentration at specific points and reducing the overall bending moment during tab convergence.
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 effectively suppresses cracks and delamination, improving input/output characteristics and durability while reducing the battery's volume, thereby enhancing energy density.
Implementation Method 1
a stress relaxation section in a bending region formed when binding a plurality of the current collector tabs in a solid-state battery cell
Data Source
AI summary
Provided are: a current collector tab for solid-state batteries that minimizes the occurrence of cracks in an electrode active material and that makes it possible to minimize peeling within an electrode sheet or interlayer peeling in a layered body of an electrode and a solid electrolyte; a current collector; and an electrode sheet.A stress relaxation section is provided to a current collector tab for a positive electrode sheet or a negative electrode sheet.Specifically, the current collector tab for solid-state batteries comprises a stress relaxation section in a bent area occurring when a plurality of the current collector tabs are bundled in a solid-state battery cell.