All-Solid Battery Electrode Tip Structure for Crack-Free Interfaces

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Solution Overview

Problem

Existing all solid batteries face issues with interfacial cracks and misalignment between the solid electrolyte layer and internal electrode layer due to volume expansion and contraction during charging and discharging, leading to decreased battery characteristics and reliability.

Innovation Solution

The battery design incorporates a specific configuration where the internal electrode layers have a thin tip that gradually thickens inward, with a defined overlapping portion and margin structure that satisfies the relationship 0°<θ<90° and 0.1×t1/tan θ≤d≤2.0×t1/tan θ, and a curved outer shape to enhance contact area, reducing misalignment and deformation risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the internal electrode layer is made thick to ensure sufficient active material, then the battery capacity is improved, but interfacial cracks occur between the solid electrolyte layer and internal electrode layer during charging and discharging

Engineering Contradiction:

Improvebattery capacityVSAvoidinterface stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The internal electrode layer is divided into a body portion and a tip portion with different thicknesses. The body portion has a larger thickness to provide sufficient active material and battery capacity, while the tip portion has a smaller thickness to reduce volume change and prevent interfacial cracks during charging and discharging.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the internal electrode layer have different local properties: the body portion is thick for high capacity, while the tip portion is thin for stability. This local differentiation allows the electrode to simultaneously achieve high capacity and interface stability.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If the internal electrode layer is made thick to increase capacity, then the battery characteristics are improved, but misalignment between the solid electrolyte layer and internal electrode layer occurs

Engineering Contradiction:

Improvebattery capacityVSAvoidalignment precision

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The internal electrode layer is segmented into a body portion and a tip portion, where the tip portion extends beyond the solid electrolyte layer in the stacking direction. This segmentation allows the thick body to provide capacity while the thinner tip accommodates alignment tolerances without causing misalignment issues.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tip portion of the internal electrode layer protrudes from the solid electrolyte layer in advance, creating a buffer zone that compensates for potential misalignment during assembly. This beforehand cushioning prevents misalignment between the solid electrolyte layer and the main body of the internal electrode layer.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Duration of action of moving object

If the internal electrode layer undergoes volume expansion and contraction during charging and discharging, then the battery functionality is maintained, but interfacial cracks and deformation occur

Engineering Contradiction:

Improvebattery cycle lifeVSAvoidinterface strength

Core Design Contradiction:

Duration of action of moving objectVSStrength

Solution Approach 1:

The internal electrode layer is divided into a body portion and a tip portion with different thicknesses. The tip portion's smaller thickness reduces its volume change during charging and discharging, thereby minimizing the generation of interfacial cracks and maintaining interface strength while preserving battery functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250300158A1All solid battery

Publication Date: 2025.09.25 TAIYO YUDEN KK

AI summary

An all solid battery includes a first overlapping portion in which a tip of a first internal electrode layer and a part of a first margin overlap each other, viewed along a stacking direction. 0°<θ<90° and 0.1×t1/tan θ≤d<2.0×t1/tan θ are satisfied when in the first overlapping portion, an angle formed by a straight line connecting a tip point E1 of the first internal electrode layer on the first margin side and a tip point E2 of the first margin on the first internal electrode layer side and a straight line connecting both ends of the first internal electrode layer is “θ”, a thickness of the first margin is “t1”, and a length between the tip point E1 and the tip point E2 in the third direction is “d”.