Lithium Battery Positive Electrode Single Particles Thermal Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face challenges in achieving thermal stability and safety as they increase in volume, leading to potential ignition or explosion due to heat and gas generation, especially during quick charging, as the existing electrode tab design concentrates electric current and increases resistance.
Innovation Solution
Incorporating single particles or quasi-single particles with an average particle diameter of 5 μm or less as the positive electrode active material, along with a tab-less structure where uncoated portions of the electrode plates serve as electrode tabs, to minimize resistance and gas generation, and using a silicon-containing negative electrode active material for higher energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the battery volume is increased to achieve high capacity, then the energy storage increases, but the heat generation and gas production increase leading to safety risks
Solution Approach 1:
The patent changes the particle size parameter of the positive electrode active material to D50 of 5 μm or less, which fundamentally alters the electrochemical reaction characteristics. This parameter change reduces internal resistance and heat generation during charging/discharging, enabling high capacity batteries to maintain safety even at large volumes.
Solution Approach 2:
The patent applies surface coating treatments to the positive electrode active material particles before electrode fabrication. This beforehand cushioning protects particles from breakage during manufacturing and operation, preventing internal crack formation that would otherwise lead to gas generation and safety issues in large-capacity batteries.
2Ease of manufacture
If electrode tabs with strip shape are used for current collection, then the manufacturing is simple, but the electric current concentration increases resistance and heat generation
Solution Approach 1:
The patent transitions from traditional strip-shaped electrode tabs to uncoated portion-based tabs where the current collection area extends in multiple dimensions along the electrode plate. This dimensional change increases the effective current collection area without complicating manufacturing, reducing current density and associated heat generation.
3Quantity of substance
If secondary particles are used as positive electrode active material, then the volumetric energy density increases, but particle breakage and internal cracks occur during manufacturing and operation
Solution Approach 1:
The patent changes the particle size parameter to D50 of 5 μm or less, which fundamentally alters the mechanical strength-to-volume ratio. Smaller particles maintain structural integrity during manufacturing and operation while still achieving high volumetric energy density through optimized packing and surface area utilization.
4Volume of stationary object
If the cross-sectional area for heat discharge is increased proportionally with battery volume, then the heat dissipation improves, but the cross-sectional area increment is less than volume increment leading to insufficient heat management
Solution Approach 1:
The patent changes the intrinsic heat generation parameter by reducing particle size to D50 of 5 μm or less. This reduces the total heat generation rate within the battery, allowing the existing cross-sectional area for heat discharge to remain sufficient even as battery volume increases, eliminating the scaling problem.
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 safety and capacity characteristics by reducing particle breakage and internal cracks, minimizing heat generation, and improving thermal stability, even in large batteries, while maintaining high energy density.
Implementation Method 1
the positive electrode active material layer includes a positive electrode active material which has an average particle diameter D50 of 5 μm or less and contains single particles, quasi-single particles, or a combination thereof
Implementation Method 2
electric current is concentrated on the electrode tab having a strip shape, and thus, resistance increases, a large amount of heat is generated
Implementation Method 3
using a silicon-containing negative electrode active material for higher energy density
Data Source
AI summary
Disclosed is a lithium secondary battery including: an electrode assembly in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are wound in one direction; a battery can in which the electrode assembly is accommodated; and a sealing body which seals an open end of the battery can. The positive electrode plate includes a positive electrode active material, and the positive electrode active material includes single particles or quasi-single particles, having an average particle diameter D50 of 5 μm or less.