All-solid lithium battery metallic lithium absorption layer

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Solution Overview

Problem

Lithium secondary batteries face challenges in detecting deterioration before internal short circuiting occurs due to metallic lithium dendrite growth, as existing methods fail to effectively restrict dendrite growth and detect battery degradation until short circuiting happens.

Innovation Solution

An all-solid lithium secondary battery design incorporating a metallic lithium absorption layer with a reactive substance that generates a stable electron conductor, along with a solid electrolyte layer, which restricts dendrite growth and allows for detection of battery deterioration by measuring charging and discharging capacities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separator is used to restrict internal short circuiting, then reliability is improved, but the ability to detect deterioration before short circuiting occurs is insufficient

Engineering Contradiction:
Improverestriction of internal short circuitingVSAvoiddetection of battery deterioration
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces a metallic lithium absorption layer that reacts with dendrites before they can cause internal short circuiting. This preliminary reaction generates an irreversible capacity signal that serves as an early warning of dendrite growth and battery deterioration, enabling detection before catastrophic failure occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a feedback mechanism where the reaction between the metallic lithium absorption layer and dendrites generates an irreversible capacity signal. This signal provides continuous feedback about the battery's internal state, allowing monitoring of dendrite growth and early detection of deterioration through capacity measurements.

Inventive Principle:
Principle #23Feedback

2Use of energy by moving object

If multiple solid electrolyte layers are disposed to reduce internal resistance and improve ionic conductivity, then energy density is improved, but the complexity of the battery structure increases

Engineering Contradiction:
Improveionic conductivity and energy densityVSAvoidbattery structure complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent combines the functions of dendrite restriction and capacity monitoring into a single metallic lithium absorption layer. This layer simultaneously restricts internal short circuiting and generates detectable irreversible capacity signals, eliminating the need for separate monitoring components and reducing overall structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metallic lithium absorption layer serves multiple functions: it restricts internal short circuiting by reacting with dendrites, generates irreversible capacity signals for deterioration detection, and maintains ionic conductivity. This multi-functionality reduces the number of separate components needed, simplifying the battery structure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Difficulty of detecting and measuring

If a metallic lithium absorption layer is introduced to detect dendrite growth, then deterioration detection capability is improved, but the battery structure becomes more complex

Engineering Contradiction:
Improvedetection of battery deteriorationVSAvoidbattery structure complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent combines the functions of dendrite restriction and capacity monitoring into a single metallic lithium absorption layer. This layer simultaneously restricts internal short circuiting and generates detectable irreversible capacity signals, eliminating the need for separate monitoring components and reducing overall structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The metallic lithium absorption layer serves itself by reacting with dendrites to generate the very signal needed for detection. The layer's chemical reaction with dendrites automatically produces irreversible capacity changes that can be measured, eliminating the need for external sensing mechanisms.

Inventive Principle:
Principle #25Self-service

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 effectively restricts internal short circuiting and allows for early detection of deterioration by generating an irreversible capacity when dendrites reach the absorption layer, enabling timely replacement or adjustment of the battery.

Implementation Method 1

a metallic lithium absorption layer containing a metallic lithium reactive substance that reacts with metallic lithium to generate an electron conductor which is stable under battery charging and discharging conditions

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

The solid electrolyte contained in the first solid electrolyte layer is a crystalline or amorphous sulfide solid electrolyte or a crystalline or amorphous oxide solid electrolyte

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP3654435B1All-solid lithium secondary battery, and deterioration determination method of all-solid lithium secondary battery
Publication Date: 2022.06.22 TOYOTA JIDOSHA KK
  • EP3654435B1 patent drawingFigure 1A~1C
  • EP3654435B1 patent drawingFigure 2A~2C
  • EP3654435B1 patent drawingFigure 3A~3C

AI summary

An all-solid lithium secondary battery (10c) includes a positive electrode active material layer (2), a metallic lithium absorption layer (7), a solid electrolyte layer (3), and a negative electrode active material layer (4) in this order. The solid electrolyte layer (3) is in contact with the negative electrode active material layer (4). The metallic lithium absorption layer (7) contains a metallic lithium reactive substance. The metallic lithium reactive substance reacts with metallic lithium to generate an electron conductor which is stable under charging and discharging conditions of the all-solid lithium secondary battery.