All-solid battery cross-linked polymer layer sealing

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Solution Overview

Problem

The manufacturing of solid-state lithium-ion batteries faces challenges due to the large volume variations of lithium anodes during charging and discharging, which complicates encapsulation and can lead to sealing issues, and the implementation of ion-conductive glasses with low glass transition temperatures that may crystallize during battery assembly, affecting ion conduction properties.

Innovation Solution

A method for manufacturing all-solid thin-film batteries involving the deposition of anode, cathode, and solid electrolyte layers using techniques like electrophoresis, followed by heat treatment and mechanical compression, with a crosslinked polymer layer of ionic groups to enhance stability and conductivity, allowing for a multilayer structure assembly at relatively low temperatures without organic solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium anodes are used in solid-state batteries, then high energy density is achieved, but large volume variations during charging and discharging occur, making encapsulation difficult and risking sealing failure

Engineering Contradiction:
Improveenergy densityVSAvoidsealing reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent employs a flexible encapsulation layer that can accommodate the volume variations of the lithium anode during charging and discharging cycles. This flexible film structure maintains sealing integrity while allowing the anode to expand and contract, thus preserving both high energy density and reliable sealing.

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If ion-conductive glasses with low glass transition temperature are used as solid electrolyte, then good ion conduction properties are achieved, but the electrolyte may partially crystallize during battery assembly, degrading ion conduction

Engineering Contradiction:
Improveion conductionVSAvoidelectrolyte composition stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent modifies the glass transition temperature parameter of the solid electrolyte by selecting specific glass compositions with sufficiently high Tg values. This ensures that the electrolyte remains in the glassy state during battery assembly and operation, preventing crystallization while maintaining good ion conduction properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite solid electrolyte materials that combine glass matrices with specific additives or modifiers. This composite structure enhances both the glass transition temperature and ion conduction properties, preventing crystallization during assembly while maintaining electrochemical performance.

Inventive Principle:
Principle #40Composite materials

3Reliability

If two formulations of electrolytes based on lithium phosphates are deposited on each face of the electrodes, then optimal performance is achieved, but the risk of interdiffusion and formation of non-conductive phases increases

Engineering Contradiction:
Improveelectrolyte performanceVSAvoidinterdiffusion of electrolytes
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a buffer layer or interface modification between the two different electrolyte formulations. This intermediary structure prevents direct contact and interdiffusion between the electrolytes, avoiding the formation of non-conductive phases while allowing each electrolyte to maintain its optimal performance characteristics.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method enables the production of batteries with improved energy and power density, reliable behavior, and extended lifespan by maintaining surface capacities and preventing cracking or defects, while avoiding the risks of solvent ignition and short-circuits.

Implementation Method 1

The electrophoresis process, which makes it possible to deposit, in thin layers, nanoparticles respectively of anode, cathode and electrolyte materials

Methodology Applied
Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 2

heat treatment and/or mechanical compression of the stack obtained in step e) is carried out to obtain an entirely solid thin-film battery

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP3164904B1All-solid battery including a solid electrolyte and a layer of polymer material
Publication Date: 2021.03.31 I TEN
  • EP3164904B1 patent drawingFigure 1
  • EP3164904B1 patent drawingFigure 2

AI summary

The invention relates to a method for manufacturing an all-solid thin-film battery including the following consecutive steps: a) depositing a layer including at least one anode material on the conductive substrate thereof; b) depositing a layer including at least one cathode material on the conductive substrate thereof; c) depositing a layer including at least one solid electrolyte material on at least one layer obtained in step a) and/or b); d) depositing a layer of a cross-linked polymer material comprising ion groupings with a thickness of less than 10 µm, preferably less than 5 µm, and more preferably less than 2 µm: either on the layer of anode material coated with a layer of solid electrolyte material and/or on the layer of cathode material optionally coated with a layer of solid electrolyte material, or on the layer of cathode material coated with a layer of solid electrolyte material and/or on the layer of anode material optionally coated with a layer of solid electrolyte material; e) consecutively stacking, face-to-face, a layer of anode material obtained in steps a), c) or d) with a layer of cathode material obtained in steps b), c) or d), with the understanding that the stack includes at least one layer of solid electrolyte material obtained in step c) and at least one layer of cross-linked polymer material obtained in step d); f) thermally treating and/or a mechanically compressing of the stack obtained in step e) in order to obtain an all-solid thin-film battery.