Non-aqueous Electrolyte Battery Anode with Columnar Segmentation

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Solution Overview

Problem

Non-aqueous electrolyte secondary batteries using metal anode active materials like tin or silicon face reactivity issues with lithium salts and solvents, leading to deterioration and reduced charge-discharge cycle performance.

Innovation Solution

Incorporating a compound represented by the formula A-N=C=O in the non-aqueous electrolyte, where the anode active material is shaped into columns with gaps, preventing reaction between the anode and electrolyte and enhancing cycle performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If metal anode active materials like tin or silicon are used to enhance charge-discharge capacity, then the charge-discharge capacity per unit mass or unit volume is improved, but the reactivity towards lithium salts or non-aqueous solvent increases leading to deterioration and expanding of the anode active material

Engineering Contradiction:

Improvecharge-discharge capacityVSAvoidcharge-discharge cycle performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces a protective layer formed from decomposition products of the non-aqueous solvent as an intermediary between the metal anode active material and the electrolyte. This protective layer mediates the interaction by preventing direct contact and reaction between the reactive metal surface and the electrolyte components, thereby resolving the contradiction between high capacity and cycle stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs preliminary action by forming a protective layer on the surface of the metal anode active material before it undergoes significant deterioration. This is achieved through initial charge-discharge cycles or by adding protective agents to the electrolyte that decompose first to form a stable surface layer, preventing subsequent harmful reactions during normal operation

Inventive Principle:

Principle #10Preliminary action

2Productivity

If a thin layer of anode active material is formed to improve charge-discharge capacity, then the capacity per unit volume is enhanced, but stress from expanding/shrinkage during charge-discharge cycle can disconnect the thin layer from the current collector

Engineering Contradiction:

Improvecharge-discharge capacity per unit volumeVSAvoidadhesion to current collector

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent applies segmentation by dividing the thin layer of anode active material into columns through gaps formed in the thickness direction. This segmentation allows each column to independently expand and shrink during charge-discharge cycles without generating sufficient stress to disconnect the layer from the current collector, while maintaining high capacity density

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses local quality by creating regions of different mechanical properties within the anode structure. The columnar structure with gaps provides local flexibility to accommodate volume changes, while the base layer maintains strong adhesion to the current collector, allowing the structure to handle stress locally without overall detachment

Inventive Principle:

Principle #3Local quality

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 configuration effectively prevents anode material deterioration and improves charge-discharge cycle characteristics by reducing reactivity and stress on the anode, leading to enhanced battery performance.

Implementation Method 1

a compound having a structure represented by the following formula (I) is contained in the non-aqueous electrolyte: A-N=C=O (I) (wherein A represents an element or a group other than hydrogen)

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

a non-aqueous electrolyte containing lithium salt dissolved in a non-aqueous solvent

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 3

anode active material containing a metal which absorbs and discharges lithium

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 4

making use of oxidation and reduction of lithium

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentUS8673504B2Non-aqueous electrolyte secondary battery and non-aqueous electrolyte

Publication Date: 2014.03.18 PANASONIC ENERGY CO LTD

AI summary

The objective of the present invention is to prevent deterioration and expanding of anode active material and to improve charge-discharge cycle characteristics in a non-aqueous electrolyte secondary battery comprising an anode of which current collector has thereon a thin layer of an anode active material containing a metal. To solve this problem, in a non-aqueous electrolyte secondary battery wherein a thin layer of anode active material containing a metal which absorbs and discharges lithium is formed on a current collector and the thin layer of the anode active material is divided into columns by a gap formed along the thickness thereof, a compound represented by the following formula is contained in the non-aqueous electrolyte.A-N═C═OIn the above formula, A represents an element or a group other than hydrogen.