All solid state battery
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Solution Overview
Problem
Current all solid state batteries face challenges in achieving excellent cycle characteristics due to anisotropic tensile strength in nonwoven fabrics used for solid electrolytes, leading to internal short circuits and degraded performance.
Innovation Solution
The battery design incorporates a nonwoven fabric with a specific angle between the fabric direction and the facing part, ensuring a rectangular shape with a longer side to shorter side ratio of 1.5 or more, and a void rate of 70% to 90%, using an inorganic solid electrolyte like sulfide, oxide, or hydride, which moderates tensile strength anisotropy and maintains uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nonwoven fabric is used for the solid electrolyte layer, then the battery structure is simplified and manufacturing is easier, but the anisotropic tensile strength causes internal short circuits and degraded cycle characteristics
Solution Approach 1:
The patent applies asymmetry by intentionally aligning the fabric direction of the nonwoven fabric with the longer direction of the rectangular facing part. This asymmetric alignment (where the fabric's inherent anisotropic strength direction matches the geometric asymmetry of the rectangular structure) ensures that the maximum tensile strength direction coincides with the direction experiencing greater dimensional changes during battery operation, preventing internal short circuits while maintaining manufacturing simplicity.
2Reliability
If the nonwoven fabric has high void rate for ion conductivity, then ion transport is improved, but the structural integrity and insulation properties are reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the void rate of the nonwoven fabric to a specific range (70-90%). This parameter optimization balances the competing requirements: sufficient void space for ion transport while maintaining enough solid material for structural integrity and insulation. The specific void rate range represents a critical threshold that simultaneously satisfies both ion conductivity and mechanical strength requirements.
3Device complexity
If the facing part has a rectangular shape with specific aspect ratio, then the battery design is simplified, but the alignment with nonwoven fabric direction becomes critical for performance
Solution Approach 1:
The patent applies asymmetry by designing the facing part with a rectangular shape where the longer direction is specifically aligned with the fabric direction of the nonwoven fabric. This asymmetric geometric design (aspect ratio ≥ 1.5) simplifies the overall device structure while creating a clear alignment rule that guides manufacturing. The rectangular asymmetry transforms the anisotropic weakness into a directional strength by matching it with the geometric asymmetry of the battery design.
Data Source
AI summary
An all solid state battery includes an electrode structure body including a cathode layer, an anode layer, and a solid electrolyte layer arranged between the cathode layer and the anode layer, wherein: the electrode structure body includes a facing part where the cathode layer and the anode layer face to each other; in a plan view along a thickness direction, a shape of the facing part is a rectangular shape including a longer side and a shorter side; a rate of a length of the longer side with respect to a length of the shorter side is 1.5 or more; the solid electrolyte layer contains a nonwoven fabric, and a solid electrolyte arranged inside the nonwoven fabric; and in the plan view, an angle formed by a longer direction in the facing part and a fabric direction in the nonwoven fabric is 0° or more and 30° or less.