Rubber-Clad All-Solid Secondary Cell for Vibration Stability

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Solution Overview

Problem

All-solid state secondary batteries face challenges in maintaining voltage stability and cycle characteristics when subjected to continuous vibrations, such as those experienced in vehicles, due to the low modulus of elasticity in existing elastic layers and lack of vibration performance degradation studies in previous battery systems.

Innovation Solution

The implementation of a rubber-coating layer with a gas transmission coefficient of less than 40 cc·20 µm/m²·24 h atm on the exterior of the battery, which absorbs vibrations and prevents gas intrusion from the lamination interface, thereby maintaining discharge capacity density and cycle characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an elastic layer with low modulus of elasticity is used in all-solid state secondary batteries, then the battery shows flexibility and water resistance, but the battery performance degrades when continuously receiving vibrations

Engineering Contradiction:

ImproveflexibilityVSAvoidbattery performance stability under vibration

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the key parameter of the exterior material from low modulus of elasticity to high modulus of elasticity (specifically 0.1 to 10 GPa). This parameter change allows the material to maintain flexibility and protection while resisting vibration-induced deformation, thereby preventing battery performance degradation under continuous vibration conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures in the exterior material layer, combining materials with specific mechanical properties to achieve both flexibility and vibration resistance. The composite structure allows the exterior material to maintain adaptability while providing sufficient structural support to prevent performance degradation under vibration.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the exterior material layer does not prevent gas intrusion at the lamination interface, then manufacturing is simpler, but discharge capacity density and cycle characteristics degrade under vibration

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddischarge capacity density and cycle characteristic

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a flexible exterior material layer (thin film structure) that conforms to the battery laminate shape while providing gas barrier protection. This flexible shell approach prevents gas intrusion at the lamination interface without significantly complicating the manufacturing process, maintaining both ease of manufacture and reliable battery performance.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The exterior material layer serves as a protective barrier that prevents gas intrusion and protects the battery interface. By providing this protective function, the patent prevents performance degradation without requiring complex sealing structures, thus maintaining manufacturing simplicity while ensuring reliable discharge capacity density and cycle characteristics.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 solution effectively suppresses the impact of vibrations on the battery, maintaining high discharge capacity density and voltage stability, and enhancing cycle characteristics, even under conditions of continuous vibration.

Implementation Method 1

the rubber-coating layer having a gas transmission coefficient of less than 40 cc·20 µm/m²·24 h atm and a modulus of elasticity at 25° C. of 0.01 to 100 MPa

Methodology Applied

Scientific EffectVibration absorption: Damping

Implementation Method 2

the rubber-coating layer having a gas transmission coefficient of less than 40 cc·20 µm/m²·24 h atm

Methodology Applied

Scientific EffectGas transmission barrier: Permeation

Data Source

PatentEP3683884B1All-solid secondary cell, outer cladding material for all-solid secondary cell, and method for manufacturing said all-solid secondary cell

Publication Date: 2024.02.28 FUJIFILM CORP

Figure 1~2

AI summary

Provided are an all-solid state secondary battery including a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer and being coated with an exterior material layer, in which at least a part of the exterior material layer is a rubber-coating layer having a gas transmission coefficient of less than 40 cc·20 µm/m2·24 h·atm, an exterior material for an all-solid state secondary battery, and an all-solid state secondary battery.