Silicon-Copper Oxide Anode for Battery Volume Expansion

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Solution Overview

Problem

Conventional nonaqueous electrolyte secondary batteries face limitations in increasing charge/discharge capacity and stability due to the low material density of carbonaceous anode materials, which leads to volume expansion issues and potential internal short-circuiting, especially when using single metals like silicon as anode materials.

Innovation Solution

The use of a nonaqueous electrolyte secondary battery design incorporating a cathode active material layer with lithium-copper oxide and copper oxide, where the peak intensity ratio of X-ray diffraction peaks from lithium-copper oxide to copper oxide is between 0.1 and 0.5, and an anode active material layer with a combination of silicon and copper oxide, optimized to maintain lithium supply and reduce volume expansion, is proposed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If single metal (Si, Al, Ge, Sn, or Sb) is used as anode material to achieve higher capacity than carbonaceous material, then charge/discharge capacity is improved, but microscopic pulverization occurs and charge-discharge cycling characteristics deteriorate

Engineering Contradiction:

Improvecharge/discharge capacityVSAvoidcharge-discharge cycling characteristics

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies composite materials by combining single metal particles (Si, Al, Ge, Sn, or Sb) with conductive carbon material and binder to form an anode active material layer. This composite structure allows the single metal to provide high capacity while the carbon matrix and binder prevent pulverization during cycling, resolving the contradiction between achieving high capacity and maintaining cycling stability.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If improved high-capacity tin oxide or silicon oxide is used, then capacity and cycling characteristics are improved, but volume expansion during charge causes copper foil deformation and internal short-circuiting

Engineering Contradiction:

ImprovecapacityVSAvoidinternal short-circuiting

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent uses a flexible carbonaceous material matrix as a shell or coating around the tin oxide or silicon oxide particles. This carbon shell accommodates the volume expansion during charge by deforming elastically, preventing direct transmission of expansion stress to the copper foil collector. This resolves the contradiction between achieving high capacity through oxide materials and preventing internal short-circuiting caused by foil deformation.

Inventive Principle:

Principle #30Flexible shells and thin films

3Stability of the object's composition

If conventional carbonaceous material is used as anode, then structural stability is maintained, but charge/discharge capacity per unit volume is limited due to low material density

Engineering Contradiction:

Improvestructural stabilityVSAvoidcharge/discharge capacity per unit volume

Core Design Contradiction:

Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent creates a composite anode structure where high-capacity single metal particles or oxide particles are dispersed within a carbonaceous material matrix. The carbon matrix provides structural stability and conductivity, while the high-capacity particles contribute to increased capacity per unit volume. This composite approach resolves the contradiction between maintaining structural stability and increasing volumetric capacity.

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

This configuration enhances charge-discharge cycle performance, increases capacity retention, and reduces the risk of internal short-circuiting, achieving higher capacity and stability compared to conventional batteries.

Implementation Method 1

an anode that includes an anode active material housed in the exterior member, the anode active material being spatially separated from the cathode via a separator

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

A peak intensity ratio d(002)/d(010) between a plane index d(010) derived from the lithium-copper oxide and a plane index d(002) derived from the copper oxide is not lower than 0.1 and not higher than 0.5 at an X-ray diffraction peak

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentUS9831492B2Nonaqueous electrolyte secondary battery and battery pack

Publication Date: 2017.11.28 KK TOSHIBA

AI summary

A nonaqueous electrolyte secondary battery of an embodiment includes an exterior member, a cathode including a cathode active material layer housed in the exterior member, an anode including an anode active material layer housed in the exterior member and spatially separated from the cathode by a separator, and a nonaqueous electrolyte filled in the exterior member. The cathode active material layer contains lithium-copper oxide and copper oxide. A peak intensity ratio d(002)/d(010) between a plane index d(010) derived from the lithium-copper oxide and a plane index d(002) derived from the copper oxide is not lower than 0.1 and not higher than 0.5 at an X-ray diffraction peak.