Positive Electrode Flame-Retardant Layer for Low-Resistance Battery Safety
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Solution Overview
Problem
Existing non-aqueous electrolyte rechargeable batteries, such as lithium ion batteries, face challenges in safely managing internal temperature rises due to oxidative decomposition reactions, which can lead to short circuits and instability, despite the use of flame retardant layers, as these measures often increase electrical resistance and deteriorate cycle characteristics.
Innovation Solution
A positive electrode with a flame retardant layer comprising composite particles made of metal hydroxides and flame retardants, specifically designed to capture radicals and absorb heat through endothermic reactions, is implemented, with optimized particle size, surface area, and composition to suppress internal temperature increases while maintaining battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flame retardant layer is formed on the surface of the positive electrode to suppress internal temperature rise, then safety is improved, but electrical resistance increases and cycle characteristics deteriorate
Solution Approach 1:
The patent uses composite particles comprising metal hydroxide and flame retardant materials to create a flame retardant layer that combines heat absorption capabilities with radical trapping functionality. This composite structure allows the layer to suppress internal temperature rise while maintaining better electrical properties compared to conventional single-material flame retardant layers
Solution Approach 2:
The patent optimizes specific parameters including the particle size distribution (D50 and D90 values), specific surface area (BET), and thermal desorption characteristics (P2 amount from 80°C to 1400°C) of the composite particles to achieve the desired balance between safety and electrical performance
2Reliability
If a flame retardant layer is formed on the surface of the positive electrode to suppress internal temperature rise, then safety is improved, but cycle characteristics deteriorate
Solution Approach 1:
The composite particle structure combines metal hydroxide with flame retardant materials to create a multi-functional layer that provides both thermal management and radical trapping capabilities, thereby improving cycle stability while maintaining safety
Solution Approach 2:
The patent specifies optimal ranges for particle size parameters (D50 ≥ 0.05 μm and ≤ 3 μm, D90 ≤ 5 μm) and specific surface area (BET ≥ 8 m²/g) to ensure the flame retardant layer maintains good cycle characteristics while providing sufficient safety protection
3Object-generated harmful factors
If conventional flame retardant materials are used to suppress oxidative decomposition, then radical capture ability is improved, but internal temperature cannot be sufficiently suppressed
Solution Approach 1:
The patent creates composite particles that combine metal hydroxide (which provides endothermic heat absorption through decomposition) with flame retardant materials (which provide radical trapping capability). This composite structure enables simultaneous suppression of both temperature rise and oxidative decomposition
Solution Approach 2:
The patent merges two distinct functional materials - metal hydroxide for heat absorption and flame retardant for radical capture - into a single composite particle system, allowing both functions to work synergistically in the flame retardant layer
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 suppresses internal temperature rises, reduces electrical resistance, and improves cycle characteristics of non-aqueous electrolyte rechargeable batteries, ensuring safer and more efficient battery operation.
Implementation Method 1
an endothermic reaction occurs in the composite particles. This causes radical capture by the flame retardant and suppresses an electrolyte decomposition reaction
Implementation Method 2
This causes radical capture by the flame retardant and suppresses an electrolyte decomposition reaction
Data Source
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AI summary
A positive electrode for a non-aqueous electrolyte rechargeable battery is provided that can sufficiently suppress a rise in an internal temperature of the battery to improve safety, while also improving battery performance such as electrical resistance and cycle characteristics. A positive electrode for a non-aqueous electrolyte rechargeable battery includes a positive electrode current collector, a positive electrode mixture layer on the positive electrode current collector, and a flame retardant layer on a surface of the positive electrode mixture layer opposite to the current collector, wherein the flame retardant layer includes composite particles including a metal hydroxide and a flame retardant, an amount of desorbed P2 (MS1) of the composite particles from about 80 °C to about 1400 °C as determined by thermal desorption gas mass spectrometry (TDS-MS) is greater than or equal to about 200×10-6 mol/g and less than or equal to about 2500×10-6 mol/g, and an amount of desorbed H2O (MS2) from about 80 °C to about 200 °C by TDS-MS is greater than or equal to about 50×10-6 mol/g and less than or equal to about 1000×10-6 mol/g.