Crystalline Silicon Anode Linked to Current Collector

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Solution Overview

Problem

The challenge is to improve the cycle characteristics and initial charge and discharge characteristics of lithium-ion secondary batteries, particularly when using silicon as the anode active material, as amorphous silicon films are prone to physical property changes and reduced contact strength with the current collector, leading to decreased battery performance.

Innovation Solution

The use of a crystalline anode active material layer linked to a copper current collector with a roughened surface, where the anode active material is alloyed with metal elements like copper, nickel, or iron, and contains oxygen, providing improved adhesion and stability to prevent expansion and shrinkage during electrode reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If evaporation method is used to deposit silicon anode active material layer, then the anode active material layer is linked to and united with anode current collector, but the silicon film becomes noncrystalline (amorphous) and physical property changes with time

Engineering Contradiction:

Improvecontact strength of anode active material layer to anode current collectorVSAvoidcrystalline structure stability of silicon film

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent changes the physical state parameter of silicon from amorphous to crystalline by controlling the deposition process. The evaporation method is optimized to produce crystalline silicon films with specific crystal orientations, fundamentally altering the structural parameter to prevent time-dependent physical property changes while maintaining strong adhesion to the current collector

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure where crystalline silicon forms a unified layer with the current collector through controlled evaporation. The crystalline silicon integrates with the substrate to form a stable composite material system that resists oxidation and maintains contact strength, combining the advantages of both the silicon active material and the current collector substrate

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If amorphous silicon is used as anode active material, then deposition is easier, but contact strength is easily lowered by oxidation and cycle characteristics are lowered

Engineering Contradiction:

Improveease of depositing silicon anode active materialVSAvoidcycle characteristics and charge and discharge characteristics of secondary battery

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the crystalline state parameter of silicon from amorphous to crystalline during the evaporation deposition process. By controlling evaporation conditions such as temperature, pressure, and deposition rate, crystalline silicon films are formed that maintain both ease of manufacture through evaporation and high reliability with improved cycle characteristics and oxidation resistance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating specific crystal orientations and structures in different regions of the deposited silicon film. The crystalline silicon is formed with preferred orientations that enhance both the manufacturing ease through evaporation and the reliability by reducing oxidation susceptibility in critical contact regions with the current collector

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 enhances the cycle characteristics and initial charge and discharge characteristics by maintaining the physical properties of the anode active material, reducing the likelihood of separation from the current collector and improving electron conductivity, resulting in higher energy density and battery performance.

Implementation Method 1

In the case where silicon is used as an anode active material, evaporation method is used as a method of forming an anode active material layer

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS10553855B2Method for forming anode having silicon active material linked to current collector

Publication Date: 2020.02.04 MURATA MFG CO LTD

AI summary

A secondary battery capable of improving the cycle characteristics and the initial charge and discharge characteristics is provided. The secondary battery includes a cathode, an anode, and an electrolytic solution. The anode has an anode active material layer on an anode current collector. The anode active material layer contains a crystalline anode active material having silicon as an element, and is linked to the anode current collector.