Negative Electrode Fire-Retardant Layer for High-Energy Secondary Batteries

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Solution Overview

Problem

High energy density non-aqueous electrolyte secondary batteries face challenges in maintaining safety during abnormal situations, such as excessive heat generation, which is not adequately addressed by existing technologies.

Innovation Solution

Incorporating a fire retardant with a halogen atom in the negative electrode layer of the battery, specifically a layer containing silicon-based active materials, to suppress temperature increases and prevent short circuits during abnormal conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the energy density of the non-aqueous electrolyte secondary battery is increased, then the battery capacity and output are improved, but the safety in abnormal situations deteriorates due to excessive heat generation

Engineering Contradiction:

Improveenergy densityVSAvoidsafety in abnormal situations

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A fire retardant layer containing a halogen atom is introduced as an intermediary between the negative electrode active material layer and the separator. This intermediate layer suppresses heat generation and prevents short circuits during abnormal situations, resolving the safety issues that arise from high energy density battery design.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The negative electrode is designed as a composite structure with multiple layers: a negative electrode active material layer containing silicon-based materials for high capacity, and a fire retardant layer containing halogen atoms for safety. This composite structure enables the battery to achieve both high energy density and improved safety in abnormal situations.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a fire retardant layer is added to suppress heat generation, then the safety is improved, but the device complexity increases

Engineering Contradiction:

ImprovesafetyVSAvoidbattery structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The negative electrode is segmented into functionally distinct layers: a negative electrode active material layer for high capacity and a fire retardant layer for safety. This segmentation allows each layer to perform its specific function optimally while maintaining overall battery performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fire retardant layer is strategically positioned only where needed - between the negative electrode active material layer and the separator - to provide localized heat suppression and short circuit prevention. This localized approach improves safety without unnecessarily complicating the entire battery structure.

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

The solution effectively enhances the safety and charge/discharge performance of the battery by reducing heat generation and maintaining high capacity without compromising battery characteristics.

Implementation Method 1

the fire retardant has a function of releasing a halogen radical when a temperature rises

Methodology Applied

Scientific EffectHalogen radical release:

Implementation Method 2

the halogen radical has a function of interrupting a radical chain reaction

Methodology Applied

Scientific EffectRadical chain reaction interruption:

Implementation Method 3

the fire retardant layer has a function of preventing a short circuit between the positive electrode and the negative electrode

Methodology Applied

Scientific EffectPhysical barrier effect:

Data Source

PatentUS20230369592A1Secondary battery

Publication Date: 2023.11.16 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

The disclosed secondary battery includes a positive electrode and a negative electrode, wherein the negative electrode includes a first layer including at least a negative electrode active material layer, and the first layer further includes a fire retardant including a halogen atom.