Positive Electrode Safety Coating for Thermal Runaway Blocking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lithium-ion batteries face safety issues such as liquid leakage, fire, and explosion due to high resistance, poor thermal barrier properties, and poor compatibility with solvents, limiting the effectiveness of PTC coatings.
Innovation Solution
A positive electrode plate coated with a safety coating layer containing functional microspheres, conductive agents, and binders, which maintains conductivity at room temperature and forms electron-blocking layers at high temperatures to prevent thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PTC coating is applied to improve safety, then thermal barrier properties are improved, but electronic conductivity deteriorates
Solution Approach 1:
The patent applies parameter changes by using a core-shell structure where the shell layer thickness is controlled at 1-100 nm scale, and the phase change temperature of the shell material is specifically selected to match the thermal runaway temperature of the battery. This nanoscale thickness control allows the coating to provide thermal barrier function while minimizing impact on electronic conductivity.
Solution Approach 2:
The patent uses composite materials by combining a conductive core material (such as metal particles or conductive oxides) with a phase-change shell material. This composite structure ensures that the coating maintains electronic conductivity through the conductive core while the shell provides thermal barrier properties through phase change at elevated temperatures.
2Reliability
If PTC coating thickness is increased to improve thermal barrier properties, then safety is improved, but internal resistance increases
Solution Approach 1:
The patent applies parameter changes by controlling the shell layer thickness within the nanoscale range of 1-100 nm. This precise thickness control provides sufficient thermal barrier properties to prevent thermal runaway while keeping the layer thin enough to minimize electron transport resistance and maintain low internal resistance.
3Reliability
If conventional PTC coating is applied, then thermal barrier properties are improved, but compatibility with solvents deteriorates
Solution Approach 1:
The patent applies parameter changes by selecting phase change materials with specific melting points (80-200°C) and controlling the shell layer thickness at nanoscale. These parameter optimizations ensure the coating remains stable and compatible with common battery solvents at operating temperatures while providing effective thermal barrier properties when temperature rises.
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 enhances battery safety by reducing internal resistance, increasing energy density, and preventing thermal runaway, while maintaining electrical conductivity and improving cycle life.
Implementation Method 1
the functional microsphere has conductivity, so that the safety coating layer has electrical conductivity at room temperature, and effectively reduce the internal resistance of the battery; when the use temperature of the positive electrode plate reaches up to the heat-sensitive temperature and above, the functional microsphere may melt to form a plurality of continuous electron blocking layers
Implementation Method 2
The functional microsphere has conductivity, so that the safety coating layer has electrical conductivity at room temperature, and effectively reduce the internal resistance of the battery
Data Source
AI summary
Disclosed are a positive electrode plate and a lithium-ion battery including the positive electrode plate. The positive electrode plate includes a positive current collector, a safety coating layer, a composite fusion layer, and a positive active material layer; the safety coating layer comprises a first conductive agent, a first binder, a functional microsphere, and an auxiliary agent. The safety coating layer has conductive performance at normal temperature, and has the advantages of increasing a contact area between an active material and the current collector, improving the electrical conductivity, and effectively reducing polarization of the battery; when the use temperature of the positive electrode plate reaches 120° C. or above, the functional microsphere will be melted to form a plurality of continuous electron blocking layers, the coating layer blocks current, internal blocking is formed inside the battery, and the occurrence of further thermal runaway of the battery is prevented.