Solid Electrolyte Composition for All Solid State Battery Bonding

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Solution Overview

Problem

Current all solid state secondary batteries lack sufficient bonding properties and ion conductivity, necessitating improvements in solid electrolyte compositions and electrode structures to enhance performance.

Innovation Solution

An all solid state secondary battery design featuring an electrode layer with an inorganic solid electrolyte and a specific polymer containing acidic functional groups, where the volume ratio of active material to inorganic solid electrolyte increases from the electrolyte layer towards the collector, and a solid electrolyte composition with a particulate shape and specific functional groups, applied to form a gradient structure for improved bonding and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional solid electrolyte compositions are used in all solid state secondary batteries, then the battery structure can be simplified with direct electrode stacking, but the bonding properties and ion conductivity are insufficient

Engineering Contradiction:

Improvebonding properties and ion conductivityVSAvoidbattery structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a composite solid electrolyte composition comprising inorganic solid electrolyte particles (such as Li2SiO3, Li3PO4, or Li2SiO2N) combined with organic solid electrolyte components. This composite structure achieves both favorable bonding properties with electrode materials and sufficient ion conductivity, while maintaining the simplified direct-stacking battery architecture.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific parameters including the volume ratio of inorganic solid electrolyte particles (0.1-10 μm diameter) to organic solid electrolyte, the particle size distribution, and the compositional ratios of different inorganic electrolytes. These parameter adjustments enable simultaneous improvement of bonding strength and ion conductivity without increasing structural complexity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If electrolytic solutions with flammable carbonate-based solvents are used in lithium ion batteries, then good ion conductivity is achieved, but safety concerns arise during overcharging

Engineering Contradiction:

ImprovesafetyVSAvoidion conductivity

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces flammable carbonate-based electrolytic solutions with solid electrolytes comprising inorganic compounds (Li2SiO3, Li3PO4, Li2SiO2N) and organic solid electrolytes. This creates an inert, non-flammable environment that eliminates safety hazards during overcharging while maintaining sufficient ion conductivity through the solid electrolyte composition optimization.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Reliability

If metal packages and copper wires are provided for sealing and connecting battery cells, then reliable electrical connections are achieved, but energy density is reduced

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts and eliminates metal packages and copper wires from the battery structure by utilizing the direct stacking architecture enabled by solid electrolytes. The solid electrolyte composition provides both ionic conduction and sufficient mechanical bonding, allowing battery cells to be connected directly without traditional metal interconnectors, thereby significantly increasing energy density while maintaining electrical connection reliability.

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

The battery achieves favorable bonding properties and ion conductivity, leading to enhanced performance and manufacturing feasibility of all solid state secondary batteries with improved energy density and safety.

Implementation Method 1

the electrode layer contains an inorganic solid electrolyte having a conductivity of ions of metals belonging to Group I or II of the periodic table

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

the electrode layer contains an inorganic solid electrolyte having a conductivity of ions of metals belonging to Group I or II of the periodic table, an active material, and a specific polymer... a polymer having at least one specific functional group selected from acidic functional groups, amide groups, or hydroxyl groups

Methodology Applied

Scientific EffectChemical bonding: Chemical Bonding

Data Source

PatentUS10868329B2All solid state secondary battery, solid electrolyte composition used therefor, electrode sheet for battery using the same, and method for manufacturing electrode sheet for battery and all solid state secondary battery

Publication Date: 2020.12.15 FUJIFILM CORP

AI summary

To provide an all solid state secondary battery capable of realizing favorable bonding properties and a favorable ion conductivity.Provided is an all solid state secondary battery having a structure in which an electrode layer is located between a collector and an inorganic solid electrolyte layer, in which the electrode layer contains an inorganic solid electrolyte having a conductivity of ions of metals belonging to Group I or II of the periodic table, an active material, and a specific polymer described below,specific polymer: a polymer having at least one specific functional group selected from acidic functional groups, amide groups, or hydroxyl groups.