All-solid-state battery multi-layer resin sealing

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Solution Overview

Problem

All-solid-state batteries with resin layers face cracking issues due to volume changes during charging and discharging, as the resin layer is prone to deformation and cracking when in close contact with the battery laminate.

Innovation Solution

A multi-layer resin structure is implemented, where the first resin layer has a lower elastic modulus than the second resin layer, allowing the first resin layer to absorb stresses from volume changes while the second resin layer provides protection, preventing cracking and maintaining the balance between flexibility and rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a resin layer is used to cover the all-solid-state battery laminate, then sealing and protection are improved, but cracking occurs due to volume changes during charging and discharging

Engineering Contradiction:

Improvesealing protectionVSAvoidcrack resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The resin layer is divided into multiple resin layers with different elastic moduli. The first resin layer has a lower elastic modulus to absorb expansion stress, while the second resin layer has a higher elastic modulus to provide structural support. This segmentation allows each layer to perform its specific function, preventing cracking while maintaining sealing protection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the resin layer structure are assigned different mechanical properties. The first resin layer directly contacting the battery laminate has lower rigidity to accommodate local volume changes, while the outer second resin layer has higher rigidity for overall protection. This local quality differentiation resolves the contradiction between flexibility and strength.

Inventive Principle:

Principle #3Local quality

2Strength

If the resin layer has high rigidity to maintain structural integrity, then protection is improved, but cracking occurs due to inability to accommodate volume changes

Engineering Contradiction:

Improvestructural integrityVSAvoidcrack prevention

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The resin layer is segmented into multiple layers with different rigidity characteristics. The first resin layer has lower rigidity to accommodate volume changes, while the second resin layer has higher rigidity to maintain structural integrity. This segmentation allows the system to simultaneously achieve both flexibility and strength.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The resin layer is constructed as a composite structure with multiple resin layers having different elastic moduli. This composite material approach combines the benefits of flexible materials (for stress absorption) and rigid materials (for structural support), resolving the contradiction between rigidity and crack resistance.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If a single-layer resin structure is used, then manufacturing is simplified, but cracking occurs due to uniform stress distribution

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidstress resistance

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The resin layer is divided into multiple resin layers with different elastic moduli. The first resin layer has lower elastic modulus to absorb expansion stress, while the second resin layer has higher elastic modulus to provide structural support. This segmentation allows each layer to perform its specific function, preventing cracking while maintaining sealing protection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

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 multi-layer resin structure effectively prevents cracking of the resin layer, ensuring the integrity of the all-solid-state battery laminate and enhancing the energy density by eliminating the need for an outer casing.

Implementation Method 1

the elastic modulus of the first resin layer is lower than the elastic modulus of the second resin layer

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS11217819B2All-solid-state battery

Publication Date: 2022.01.04 TOYOTA JIDOSHA KK

AI summary

An all-solid-state battery includes an all-solid-state battery laminate including at least one all-solid-state unit cell in which a positive electrode current collector layer, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a negative electrode current collector layer are laminated in this order, and a resin layer covering a side surface of the all-solid-state battery laminate, wherein the resin layer has a multi-layer structure including a first resin layer and a second resin layer in this order from the side in the vicinity of the side surface of the all-solid-state battery laminate, and wherein the elastic modulus of the first resin layer is lower than the elastic modulus of the second resin layer.