Thin Solid Electrolyte Sheet Layout for Uniform All-Solid-State Charging

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Solution Overview

Problem

Existing all-solid-state batteries face issues with poor charging properties when produced in large quantities, leading to decreased productivity due to non-uniform charge and discharge reactions and potential metal deposition during charging.

Innovation Solution

The battery design includes a solid electrolyte sheet with a porous substrate biased towards the positive electrode, where both surfaces of the substrate are covered with solid electrolyte, and the thickness is 50 µm or less, ensuring uniform ion movement and reducing internal resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a liquid electrolyte is used in the all-solid-state battery, then ionic conductivity is improved, but safety deteriorates due to flammability and leakage risks

Engineering Contradiction:
Improveionic conductivityVSAvoidflammability and leakage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical state parameter of the electrolyte from liquid to solid, transforming it into a solid electrolyte. This parameter change eliminates the flammability and leakage issues inherent in liquid electrolytes while maintaining ionic conductivity through the solid material's crystal structure or amorphous network

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a gel polymer electrolyte that combines the advantages of liquid electrolytes (high ionic conductivity) with the safety benefits of solid electrolytes (no leakage, non-flammable). The gel structure traps the liquid electrolyte within a polymer matrix, effectively eliminating leakage risks while maintaining the liquid's ionic transport properties

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If a solid electrolyte is used to replace liquid electrolyte, then safety is improved, but manufacturing complexity increases due to sensitivity to moisture and oxygen

Engineering Contradiction:
ImprovesafetyVSAvoidmanufacturing process complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs preliminary protective actions by coating the solid electrolyte layers with protective films before assembly, and by pre-drying all components in vacuum or inert atmosphere. These preliminary actions prevent moisture and oxygen contamination during the manufacturing process, reducing the complexity of real-time environmental control

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes inert atmosphere (nitrogen or argon) during the manufacturing and assembly processes to protect the solid electrolyte from moisture and oxygen. This creates a controlled environment that prevents degradation reactions, simplifying the manufacturing process by eliminating the need for extremely rigorous exclusion measures

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Quantity of substance

If solid electrolyte layers are used, then battery density is improved, but manufacturing precision requirements increase due to sensitivity to defects

Engineering Contradiction:
Improvebattery densityVSAvoiddefect sensitivity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent employs beforehand cushioning by introducing buffer layers and protective coatings around the solid electrolyte components. These cushioning elements accommodate minor dimensional variations and prevent defect propagation, allowing for higher battery density without requiring extremely tight manufacturing tolerances

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent utilizes flexible thin film electrolytes that can accommodate minor manufacturing variations and defects without compromising overall performance. The flexibility of these thin films allows for slight misalignments and defects to be tolerated, reducing the stringency of manufacturing precision requirements while maintaining high battery density

Inventive Principle:
Principle #30Flexible shells and thin films

4Use of energy by moving object

If all components are solidified to achieve all-solid-state battery, then energy density is improved, but contact resistance increases due to poor interfacial contact

Engineering Contradiction:
Improveenergy densityVSAvoidinterfacial contact
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces dynamic elements into the solid-state battery structure, such as compressible interfaces and flexible electrode materials that can adapt to volume changes during cycling. This dynamic design maintains good interfacial contact despite the solid state, preventing contact resistance from increasing while preserving high energy density

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs composite material structures at the interfaces between solid electrolyte and electrodes, combining materials with different mechanical and electrical properties. These composite interface layers improve contact quality by accommodating thermal expansion differences and maintaining electrical connectivity, thereby reducing contact resistance while preserving the high energy density benefits of the all-solid-state configuration

Inventive Principle:
Principle #40Composite materials

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

This configuration enhances battery productivity by minimizing charging abnormalities and metal deposition, allowing for high-volume production of reliable all-solid-state batteries.

Implementation Method 1

solid electrolyte that has come into prominence as a result of developments in recent years in the field of all-solid-state batteries

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

gel polymer electrolyte

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP4369454B1All-solid-state battery
Publication Date: 2026.04.08 MAXELL LTD
  • EP4369454B1 patent drawingFigure 1~2
  • EP4369454B1 patent drawingFigure 3~4

AI summary

Provided is an all-solid-state battery with high productivity. An all-solid-state battery according to the present invention relates to Goals 3, 7, 11, and 12 of SDGs. An all-solid-state battery according to the present invention includes a stacked body provided with a positive electrode, a negative electrode, and a solid electrolyte sheet interposed between the positive electrode and the negative electrode, in which the solid electrolyte sheet contains a porous substrate and a solid electrolyte, the solid electrolyte is retained in pores of the porous substrate, both surfaces of the porous substrate are covered with the solid electrolyte, and in the solid electrolyte sheet, the porous substrate is located biased toward the positive electrode in a thickness direction of the solid electrolyte sheet, and the solid electrolyte sheet has a thickness of 50 µm or less.