All-solid-state battery current collector with resistive layer openings

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Solution Overview

Problem

All-solid-state batteries face challenges in balancing short circuit resistance during nail penetration tests and normal usage resistance due to resistive layers, which increase battery resistance during normal operation.

Innovation Solution

An electrode current collector structure comprising a current collecting layer, a resistive layer with openings, and a coating layer, where the current collecting layer contacts the coating layer in the openings, enhancing short circuit resistance while reducing normal usage resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a resistive layer with high electron resistance is formed on the current collector surface, then short circuit resistance increases and Joule heat generation is suppressed, but battery resistance during normal usage increases

Engineering Contradiction:
Improveshort circuit resistanceVSAvoidbattery resistance during normal usage
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by creating a resistive layer with non-uniform structure - specifically with openings or voids at specific locations. This allows different regions of the current collector surface to have different electrical resistance characteristics: areas with resistive layer material provide high resistance for safety, while openings maintain low resistance pathways for normal current flow during battery operation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes porous materials by forming a resistive layer containing openings, voids, or porous structures. This porous configuration allows the layer to simultaneously provide electrical resistance in certain pathways (for safety during short circuits) while maintaining conductive pathways through the openings (for normal operation), thus resolving the contradiction between safety and performance.

Inventive Principle:
Principle #31Porous materials

2Object-affected harmful factors

If a resistive layer is formed to prevent internal short circuit, then safety during nail penetration test improves, but battery performance during normal operation deteriorates

Engineering Contradiction:
Improveinternal short circuit preventionVSAvoidbattery performance
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The resistive layer is designed with spatially varying properties through openings and voids, creating local differences in electrical resistance. This local quality variation enables the layer to provide strong resistance where needed for short circuit prevention while maintaining low resistance pathways in opening regions for normal battery performance, thus resolving the contradiction between safety and productivity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The current collector structure becomes a composite system combining conductive base material with a resistive layer containing openings. This composite structure integrates two opposing electrical resistance characteristics into a single functional element, allowing simultaneous achievement of short circuit prevention and maintained battery performance.

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

The proposed electrode current collector structure increases short circuit resistance during nail penetration tests and maintains low battery resistance during normal use by optimizing the contact resistance through the specific layer configuration and material properties.

Implementation Method 1

a coating layer, the electron conductivity of which is 2×10^-2 to 2×10^3 S/m

Methodology Applied
Scientific EffectElectron conduction: Conduction (electrical)

Implementation Method 2

Joule heat is generated since short circuit part resistance (short circuit resistance) is small, and there is a risk that the battery temperature may rise

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3407406B1Electrode current collector and all-solid-state battery
Publication Date: 2020.02.26 TOYOTA JIDOSHA KK
  • EP3407406B1 patent drawingFigure 1A~2B
  • EP3407406B1 patent drawingFigure 3A~4
  • EP3407406B1 patent drawingFigure 5A~5E

AI summary

A main object of the present disclosure is to provide an electrode current collector that allows the short circuit resistance of an all-solid-state battery to increase and also allows the resistance upon normal use of a battery to be reduced. The present disclosure achieve the object by providing an electrode current collector to be used in an all-solid-state battery, the electrode current collector comprising: a current collecting layer, a resistive layer, and a coating layer in this order; an electron conductivity of the coating layer is 2 × 10-2 S/cm or more; the resistive layer includes an opening; and the current collecting layer contacts with the coating layer in the opening.