Hollow Particle Solid Electrolyte Buffering Expansion Stress
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Solution Overview
Problem
Conventional all-solid-state batteries face issues with expansion and shrinkage of active materials during charging and discharging, leading to gaps and cracks in the solid electrolyte layer, which can cause short circuits and deteriorate battery performance.
Innovation Solution
Incorporating insulating hollow inorganic filler particles, such as titanium oxide or aluminum oxide, into the solid electrolyte layer to buffer expansion stress and prevent cracks, with a specific particle size ratio and volume ratio to maintain stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If appropriate voids are provided in advance in the solid electrolyte layer to buffer expansion stress, then gaps and cracks can be prevented, but the voids can be crushed during pressing and it is difficult to stably maintain them
Solution Approach 1:
The patent introduces hollow particles (porous structure) into the solid electrolyte layer to create void spaces that can buffer expansion stress during charging. These hollow particles maintain structural stability while providing the necessary void volume to prevent cracks without being crushed during the pressing process.
Solution Approach 2:
The patent creates a composite solid electrolyte layer by combining solid electrolyte material with hollow particles. This composite structure provides both the mechanical strength needed to withstand pressing and the void volume needed to buffer expansion stress, resolving the contradiction between maintaining void stability and preventing cracks.
2Stability of the object's composition
If pressing is performed with relatively weak pressure to avoid crushing voids, then void stability is maintained, but sufficient bonding between solid electrolyte and electrode active materials cannot be ensured and battery resistance increases
Solution Approach 1:
The hollow particles provide a porous structure that allows for weak pressing to maintain void stability while still achieving sufficient bonding. The porous nature of the hollow particles enables mechanical interlocking with electrode materials without requiring high pressing pressure, thus maintaining both void stability and bonding strength.
Solution Approach 2:
The patent changes the physical parameters of the solid electrolyte layer by incorporating hollow particles with specific size ratios (Fs/Ns ≤ 0.25). This parameter change allows the system to achieve adequate bonding at lower pressing pressures while maintaining void stability, resolving the contradiction between bonding strength and void stability.
3Reliability
If Fs/Ns ratio of hollow particles to negative electrode active material is controlled to suppress expansion stress, then gaps and cracks are prevented, but the particle size ratio must be precisely controlled
Solution Approach 1:
The patent establishes a specific parameter range (Fs/Ns ≤ 0.25) for hollow particle size relative to negative electrode active material. By controlling this size ratio parameter, the system achieves effective expansion stress buffering while providing a clear manufacturing specification that simplifies quality control and reduces manufacturing precision requirements.
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 use of hollow particles effectively prevents large gaps and cracks in the solid electrolyte layer, ensuring stable battery performance and capacity retention without increasing internal resistance.
Implementation Method 1
the solid electrolyte layer includes insulating inorganic filler particles (hereinafter also referred to as 'hollow particles') having a hollow shape at least before the initial charging
Data Source
AI summary
The solid electrolyte layer of the all-solid-state battery disclosed herein includes insulating inorganic filler particles (hollow particles) having a hollow shape at least before the initial charging. Preferably, Fs/Ns which is the ratio of an average particle diameter (Fs) of the filler particles to an average particle diameter (Ns) of the negative electrode active material is 0.25 or less at least before the initial charging. Also, preferably, Fp/Nv which is the ratio of a hollow volume (Fp) created by the hollow particles included in the solid electrolyte layer per unit area before the initial charging to an expansion volume (Nv), which is a difference between a volume after full charging and a volume before the initial charging in the negative electrode active material layer per unit area, is at least 0.1.