Lithium Microbattery Asymmetric Electrolyte Design

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Solution Overview

Problem

Lithium microbatteries face challenges with mechanical masking methods that are ineffective for small sizes, prone to contamination, and complex microfabrication processes that deteriorate functional interfaces, leading to performance issues and incompatibility with future microelectronics dimensions.

Innovation Solution

A lithium microbattery design where the solid electrolyte's dimensions are asymmetrical, with a smaller first face and a larger second face, ensuring the electrolyte is not in contact with the substrate, and using a manufacturing process involving full wafer deposition and selective wet etching to maintain interface quality and avoid contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mechanical masking is used to define patterns, then the masking process can be implemented, but it induces particulate contamination and deterioration of thin layers, and is ineffective for millimetric dimensions

Engineering Contradiction:
Improvepattern definition precisionVSAvoidparticulate contamination
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical masking with a chemical etching process using aqueous solutions. Instead of physically blocking deposition with mechanical masks, the invention uses selective chemical etching to define patterns after full wafer deposition, eliminating mechanical contact and associated contamination risks.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs aqueous etching solutions (hydraulic/liquid-based process) to selectively remove materials and define patterns. The liquid etchant flows over the deposited layers, chemically etching specific areas to create the desired microbattery structure without mechanical intervention.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Manufacturing precision

If photolithography and multiple masking levels are used to increase pattern resolution, then dimensional limits can be pushed back, but the process becomes complex and uses non-aqueous solutions incompatible with active materials, deteriorating functional interfaces

Engineering Contradiction:
Improvepattern resolutionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex photolithography and multiple masking steps from the manufacturing process. By using full wafer deposition followed by selective chemical etching, the invention removes the need for sequential masking operations, simplifying the overall process while maintaining pattern definition capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical parameters of the etching process by using aqueous solutions instead of non-aqueous etchants. This parameter change makes the process compatible with active materials like lithium phosphos oxynitride, preventing interface deterioration while achieving the desired pattern resolution.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the solid electrolyte entirely covers the first electrode including side faces, then complete coverage is achieved, but contact with the substrate or current collector causes performance reduction due to unwanted reactions

Engineering Contradiction:
Improveelectrolyte coverage completenessVSAvoidunwanted reactions with substrate
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces asymmetry in the electrolyte coverage: the electrolyte covers the top face and partial side faces of the first electrode, but deliberately stops before contacting the substrate or current collector. This asymmetric design prevents unwanted reactions at the substrate interface while maintaining sufficient coverage for functional performance.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent extracts the electrolyte coverage from complete envelopment to selective coverage. By removing the electrolyte's contact with the substrate and current collector, the invention eliminates the source of unwanted reactions while retaining the necessary coverage over the electrode for reliable operation.

Inventive Principle:
Principle #2Taking out (Extraction)

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 design enhances energy storage efficiency, reduces electrical resistance, and extends the microbattery's service life while being compatible with microelectronics technologies, offering a simpler and cost-effective manufacturing process.

Implementation Method 1

The solid electrolyte is disposed between the first electrode and the second electrode. The main faces, respectively, face each other

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

Microbatteries are in the form of a stack of solid thin layers, successively deposited on a substrate by conventional techniques of the microelectronics industry, in particular by physical vapor deposition ('physical vapor deposition', PVD)

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 3

Microbatteries are in the form of a stack of solid thin layers, successively deposited on a substrate by conventional techniques of the microelectronics industry, in particular by physical vapor deposition ('physical vapor deposition', PVD), chemical vapor deposition (CVD)

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentEP2409352B1Lithium microbattery and method for the production thereof
Publication Date: 2014.11.05 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2409352B1 patent drawingFigure 1~2
  • EP2409352B1 patent drawingFigure 3~4
  • EP2409352B1 patent drawingFigure 5~6

AI summary

The invention relates to a microbattery consisting of a pile (10) of solid thin layers on a substrate (11), successively comprising, from the substrate (11) up, a first electrode (14), a solid electrolyte (15) and a second electrode (16)/current collector (17) set. A first face and a second face of the electrolyte (18, 20) are respectively in contact with a main face (19) of the first electrode (14) and a main face (21) of the second electrode (16)/current collector (17) set. The dimensions of the main face (19) of the first electrode (14) are smaller than the dimensions of the main face (21) of said set, and the dimensions of the first face (20) of the solid electrolyte (15) are smaller than the dimensions of the second face (20) of the solid electrolyte (15). Furthermore, the solid electrolyte (15) is not in contact with the substrate (11).