Positive Electrode Protective Layer for Abuse-Resistant Li-Ion Cells
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Solution Overview
Problem
Lithium-ion batteries face high failure probabilities due to mechanical abuse, such as nail penetration or extrusion, leading to potential short circuits and thermal runaway, as conventional protective layers with low conductive agent content fail to balance safety and cycling performance effectively.
Innovation Solution
A positive electrode plate with a protective layer comprising inorganic filler conductive particles coated with materials like ATO, FTO, or ITO, and a binder, providing a wide conductive network for enhanced safety and cycling performance by preventing short circuits and maintaining battery impedance within optimal ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer with low conductive agent content is used, then safety performance is improved by preventing short circuits, but cycling performance deteriorates due to insufficient conductivity
Solution Approach 1:
The patent changes the parameters of conductive particles by coating inorganic filler surfaces with conductive materials (carbon black, graphite, or metal particles). This transformation converts non-conductive filler into conductive particles, achieving both mechanical protection and electrical conductivity without increasing layer thickness or conductive agent content
Solution Approach 2:
The patent creates composite conductive particles by combining inorganic filler (providing mechanical strength and stability) with conductive coating materials (providing electrical conductivity). This composite structure integrates the advantages of both materials, enabling the protective layer to simultaneously offer mechanical protection and electrical conductivity
2Productivity
If conductive agent content is increased to improve cycling performance, then conductivity is improved, but the protective layer becomes less effective at preventing short circuits
Solution Approach 1:
The patent transforms the fundamental parameter of conductive particles by coating inorganic filler with conductive materials. This allows the protective layer to achieve sufficient conductivity with lower overall conductive agent content, maintaining both cycling performance and short circuit prevention capabilities
3Productivity
If conventional conductive agents are used, then conductivity is provided, but the agents agglomerate and disperse poorly in the protective layer
Solution Approach 1:
The patent segments the conductive function into separate conductive particles (inorganic filler with conductive coating) that can be uniformly distributed throughout the protective layer. This segmentation prevents agglomeration by providing discrete, stable conductive units rather than large conductive agent aggregates
Solution Approach 2:
The patent uses composite particles combining inorganic filler (providing dispersion stability) with conductive coating (providing conductivity). The inorganic filler core provides structural stability and prevents agglomeration, while the conductive coating ensures electrical connectivity
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 significantly improves safety and cycling performance of lithium-ion batteries by reducing the likelihood of short circuits and maintaining energy density, while ensuring good conductivity and stability, even under mechanical abuse.
Implementation Method 1
the conductive particles have good dispersion performance, and therefore there is a wide conductive network in the positive electrode protective layer
Data Source
AI summary
A positive electrode plate includes a positive electrode active layer, and a protective electrode protective layer arranged between a positive electrode current collector and the positive electrode active layer; the positive electrode protective layer includes conductive particles and a binder; and the conductive particles are an inorganic filler with a conductive coating layer on a surface. The positive electrode protective layer is arranged to avoid a contact-type short circuit between the positive electrode current collector and a negative electrode active layer when a lithium-ion battery is mechanically abused. In addition, there is a wide conductive network in the positive electrode protective layer, so the lithium-ion battery has excellent safety performance and cycling performance.