All-Solid-State Battery Warping Suppression via High Adhesion
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Solution Overview
Problem
All-solid-state lithium ion secondary batteries face warping issues due to pressure molding, which can lead to cracking of the electrode material, especially in larger batteries, making it challenging to manufacture single-cell batteries with suppressed warping.
Innovation Solution
The battery design cancels out warping by ensuring that the positive and negative electrode current collectors and their respective layers have high adhesion, with the positive electrode current collector made of etched aluminum and the negative electrode current collector made of roughened copper, achieving a peel strength of at least 0.2 N/mm to prevent delamination and structural distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure molding is applied to reduce grain boundary resistance of electrode material, then adhesion between particles is improved and ionic conductance is enhanced, but warping of the battery structure occurs
Solution Approach 1:
The patent introduces a counterweight layer (second electrode assembly or support layer) that generates opposing force to balance the warping force from pressure molding. This counterweight compensates for the deformation, maintaining battery flatness while preserving the adhesion benefits of pressure molding.
Solution Approach 2:
The patent modifies physical parameters such as applying controlled heat treatment after pressure molding to reduce residual stress, adjusting pressure molding duration and intensity, or changing material composition ratios to minimize warping while maintaining particle adhesion.
2Reliability
If pressure molding is applied to improve adhesion between current collector and electrode material, then electrical resistance is reduced, but warping increases and may cause cracking
Solution Approach 1:
The patent applies a gradual pressure molding process with staged pressure increase, or pre-treats materials to enhance their resistance to deformation stress. This cushioning approach prevents sudden stress concentration that would cause cracking, while still achieving the desired adhesion improvement.
Solution Approach 2:
The patent optimizes pressure molding parameters (pressure level, duration, temperature) and material properties (flexibility, thickness) to reduce stress concentration. By adjusting these parameters, the patent achieves strong adhesion without exceeding the cracking threshold of the electrode material.
3Productivity
If single-cell battery design is adopted to shorten manufacturing process, then productivity is improved, but warping suppression becomes more difficult
Solution Approach 1:
The patent divides the single-cell battery into functional segments (positive electrode assembly, negative electrode assembly, support layers) that can be independently optimized. Each segment is designed with specific warping characteristics that collectively balance the overall battery structure, enabling warping suppression in single-cell configuration.
Solution Approach 2:
The patent uses composite structures combining different materials with complementary properties (e.g., flexible support layers, rigid current collectors, adaptable electrode materials). This composite approach allows the single-cell battery to achieve both manufacturing efficiency and warping resistance through material property synergies.
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 design effectively suppresses warping in single-cell all-solid-state secondary batteries, reducing the curvature by one-third compared to comparative examples, thereby enhancing the structural integrity and manufacturing feasibility of single-cell batteries.
Implementation Method 1
The positive electrode current collector and the negative electrode current collector are made of high adhesive materials, thereby reducing an electric resistance between the positive electrode current collector and the negative electrode current collector and the electrode material
Implementation Method 2
electrode materials interposed between a positive electrode current collector and a negative electrode current collector is pressure-molded in order to reduce the grain boundary resistance of an electrode material consisting of particulate matters
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
An all-solid-state secondary battery includes a positive electrode layer (2) and a negative electrode layer (4) that are disposed on a positive electrode current collector (1) and a negative electrode current collector (5), respectively, and are pressurized thereon, and a solid electrolyte layer (3) interposed between the positive electrode layer (2) and the negative electrode layer (4). The positive electrode layer (2) and the negative electrode layer (4) contain a sulfide inorganic solid electrolyte, and the positive electrode current collector (1) and the negative electrode current collector (5) have a peel strength of at least 0.2 N/mm relative to the sulfide inorganic solid electrolyte in a peel test.