Solid-State Battery Electrolyte Layer Area Mismatch

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Solution Overview

Problem

Solid-state batteries face yield and durability issues due to differences in expansion and contraction coefficients between positive and negative electrode layers, leading to delamination and breakage of the solid electrolyte, which is not adequately addressed by a single-layer solid electrolyte structure.

Innovation Solution

A solid-state battery design featuring a multi-layer solid electrolyte with varying contact areas between the positive and negative electrode layers, where the negative electrode-side electrolyte layer has a larger area and thinner thickness than the positive electrode-side electrolyte layer, and optionally includes an intermediate electrolyte layer and chamfered ends to reduce stress and prevent delamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single-layer solid electrolyte structure is used, then the device complexity is reduced, but delamination and breakage occur due to differences in expansion and contraction coefficients between electrode layers

Engineering Contradiction:

Improvesolid electrolyte structureVSAvoidlayer adhesion and electrolyte integrity

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The solid electrolyte is divided into multiple layers (first solid electrolyte layer and second solid electrolyte layer) with different contact areas with the electrode layers. This segmentation allows each layer to accommodate the expansion and contraction of different electrode layers independently, preventing delamination and breakage while maintaining structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the solid electrolyte are designed with different properties: the first solid electrolyte layer has a smaller contact area with the positive electrode layer, while the second solid electrolyte layer has a larger contact area with the negative electrode layer. This local differentiation in contact areas allows each region to adapt to the specific expansion and contraction characteristics of the adjacent electrode layer.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If the solid electrolyte layer thickness is reduced to increase capacity, then the energy density is improved, but short circuits may occur and yield decreases due to mechanical stress

Engineering Contradiction:

Improvebattery capacityVSAvoidshort circuit prevention and manufacturing yield

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The solid electrolyte is segmented into multiple layers with different thicknesses and contact areas. This allows the overall electrolyte structure to be thinner for high capacity while maintaining sufficient mechanical strength through the distributed multi-layer design, preventing short circuits and improving manufacturing yield.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The contact areas and thicknesses of different solid electrolyte layers are optimized to different parameters. The first layer has smaller contact area and appropriate thickness for the positive electrode, while the second layer has larger contact area and appropriate thickness for the negative electrode, allowing thin overall design without compromising reliability.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If integrated press process and aging process are applied, then the battery assembly is completed, but electrode layers expand and contract causing delamination and electrolyte breakage

Engineering Contradiction:

Improvemanufacturing process completionVSAvoidlayer adhesion and electrolyte integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The solid electrolyte is divided into multiple layers that can independently accommodate the expansion and contraction of different electrode layers during the integrated press process and aging process. This segmentation prevents the mechanical stress from causing delamination or breakage, ensuring reliability while maintaining manufacturing efficiency.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11652242B2Solid-state battery electrolyte layers

Publication Date: 2023.05.16 HONDA MOTOR CO LTD

AI summary

To provide a solid-state battery allowing the yield of the solid-state battery to be improved and further the durability of the solid-state battery to be improved. A solid-state battery (10) includes a positive electrode layer (3) containing a positive electrode active material, a negative electrode layer (2) containing a negative electrode active material, and a solid electrolyte (1) interposed between the positive electrode layer (3) and the negative electrode layer (2). The solid electrolyte (1) includes a positive electrode-side electrode layer (1a) in contact with the positive electrode layer (3) and a negative electrode-side electrolyte layer (1b) in contact with the negative electrode layer (2). In the solid electrolyte (1), an area SSE2 of the positive electrode side of the positive electrode-side electrolyte layer (1a) differs from an area SSE1 off the negative electrode side of the negative electrode-side electrolyte layer (1b).