Resin-Coated Silicon Negative Electrode for Battery Swelling Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Non-aqueous electrolyte secondary batteries using alloy-formable active materials, such as silicon and tin, experience performance deterioration over time due to electrode degradation and battery deformation caused by lithium absorption and desorption cycles, leading to reduced cycle characteristics and battery swelling.

Innovation Solution

A negative electrode with a resin layer containing a lithium ion-conductive resin component and additives is formed on the surface of the alloy-formable active material layer, preventing contact between newly-created surfaces and the electrolyte and maintaining additive concentration, thereby enhancing battery life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If alloy-formable active material is used as negative electrode active material, then discharge capacity is improved, but battery performance deteriorates over time due to electrode degradation and battery deformation

Engineering Contradiction:

Improvedischarge capacityVSAvoidbattery performance stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A resin layer is formed on the surface of the alloy-formable active material particles to create a protective flexible film. This resin layer acts as a shell that accommodates volume changes during lithium absorption and desorption cycles, preventing electrode degradation and battery deformation while maintaining high discharge capacity.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The negative electrode is constructed as a composite material system combining alloy-formable active material particles with a resin matrix. This composite structure integrates the high capacity benefits of alloy materials with the stability and protection provided by the resin component, resolving the contradiction between capacity and reliability.

Inventive Principle:

Principle #40Composite materials

2Productivity

If alloy-formable active material absorbs and desorbs lithium repeatedly, then high capacity is achieved, but electrode degradation and battery deformation occur

Engineering Contradiction:

Improvecharge/discharge capacityVSAvoidelectrode structural stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The resin layer is formed beforehand on the surface of the alloy-formable active material particles to provide cushioning protection. This pre-formed protective layer absorbs and mitigates the mechanical stress and volume changes that occur during repeated lithium absorption and desorption, preventing electrode degradation and maintaining structural stability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The resin layer forms a flexible protective shell around the active material particles. This flexible film accommodates the expansion and contraction of the alloy material during charge/discharge cycles, cushioning the mechanical stresses and preventing structural degradation while allowing high capacity operation.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If resin layer is formed on negative electrode active material layer, then electrode deterioration is prevented, but device complexity increases

Engineering Contradiction:

Improveelectrode durabilityVSAvoidelectrode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A single resin layer is formed on the surface of the alloy-formable active material particles to provide protection. This simple yet effective approach uses a thin film structure that prevents electrode deterioration without significantly increasing device complexity, as the resin layer can be applied as a coating rather than adding complex multi-component structures.

Inventive Principle:

Principle #30Flexible shells and thin films

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 resin layer effectively prevents electrode deterioration and maintains high cycle characteristics and reduces battery swelling, ensuring the non-aqueous electrolyte secondary battery retains performance over repeated charge/discharge cycles.

Implementation Method 1

the resin layer including a resin component with lithium ion conductivity

Methodology Applied

Scientific EffectLithium ion conductivity: Conduction (electrical)

Implementation Method 2

an alloy-formable active material capable of absorbing and desorbing lithium ions

Methodology Applied

Scientific EffectAlloying: Absorption (physical)

Data Source

PatentUS8247096B2Negative electrode for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery

Publication Date: 2012.08.21 PANASONIC HOLDINGS CORP

AI summary

In a non-aqueous electrolyte secondary battery 1 including a positive electrode 11, a negative electrode 12, a separator 14, a positive electrode lead 15, a negative electrode lead 16, a gasket 17, and a housing case 18, the negative electrode 12 including a negative electrode active material layer 12b including an alloy-formable active material, a resin layer 13 is formed on the surface of the negative electrode active material layer 12b. The resin layer 13 includes a resin component with lithium ion conductivity and an additive for non-aqueous electrolyte. This configuration enables the battery performance to be maintained at a high level and the battery swelling to be suppressed, even when the number of charge/discharge cycles is increased, providing the non-aqueous electrolyte secondary battery 1 with a high level of safety.