Battery Heat-Resistant Electrode Layer for Low Resistance Short Control
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Solution Overview
Problem
Existing non-aqueous electrolyte secondary batteries face challenges in simultaneously suppressing internal resistance increases and temperature rises during internal shorts, as heat-resistant layers either enhance internal resistance or fail to control temperature effectively.
Innovation Solution
A non-aqueous electrolyte secondary battery design featuring a heat-resistant layer with specific characteristics, including a thickness of 0.5 μm to 5 μm, porosity of 25% to 55%, and surface roughness of 0.35 μm or less, using heat-resistant particles with metal compounds having electronegativity of 13.5 or more, which are less attracted by the non-aqueous electrolyte, thereby maintaining high ion permeability and preventing both internal resistance and temperature rise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the heat-resistant layer is compressed to increase adhesion, then the adhesion is improved, but the internal resistance of the battery increases
Solution Approach 1:
The patent changes the physical and chemical parameters of the heat-resistant layer, specifically controlling the particle size (0.3-2.0 μm), porosity (30-50%), and surface roughness (Ra 0.20 μm or less) to achieve optimal balance between adhesion and ion permeability. This parameter optimization allows the layer to maintain good adhesion without excessive compression that would block ion transport.
Solution Approach 2:
The patent uses composite materials consisting of heat-resistant particles (such as alumina, silica, or boehmite) combined with specific binders in controlled ratios. This composite structure provides both mechanical adhesion strength and sufficient porosity for ion permeability, resolving the contradiction between strong bonding and ion transport.
2Reliability
If the heat-resistant layer is not compressed, then the ion permeability is improved, but the adhesion is insufficient and temperature rise upon internal short cannot be suppressed
Solution Approach 1:
The patent optimizes the porosity parameter to 30-50% and surface roughness to Ra 0.20 μm or less, which maintains high ion permeability while providing sufficient mechanical adhesion. The controlled particle size distribution (0.3-2.0 μm) also contributes to both adhesion and permeability.
Solution Approach 2:
The patent employs a porous heat-resistant layer with controlled porosity (30-50%) that allows efficient ion transport while the porous structure itself provides mechanical interlocking for adhesion. The porosity is optimized to balance ion permeability requirements with structural integrity and adhesion needs.
3Temperature
If the heat-resistant layer is formed to suppress temperature rise upon internal short, then the temperature control is improved, but the internal resistance increases due to reduced ion permeability
Solution Approach 1:
The patent carefully controls the thickness (5-20 μm), porosity (30-50%), and particle size (0.3-2.0 μm) parameters to achieve the right balance. These parameter optimizations ensure the layer is thin enough and porous enough to maintain ion permeability and low internal resistance, while still providing sufficient thermal barrier function.
Solution Approach 2:
The patent applies local quality by creating a heat-resistant layer with specific regional characteristics - the layer has controlled porosity and particle distribution that provides thermal protection where needed while maintaining ion transport pathways. The surface roughness control (Ra 0.20 μm or less) ensures good interface quality for ion transport.
4Strength
If a thicker heat-resistant layer is used to improve adhesion and thermal protection, then the adhesion and temperature suppression are improved, but the ion permeability decreases and internal resistance increases
Solution Approach 1:
The patent optimizes the thickness parameter to a specific range (5-20 μm) that provides sufficient adhesion and thermal protection without being so thick as to block ion transport. This parameter control, combined with optimized porosity (30-50%), ensures the layer is thin enough to maintain ion permeability while providing adequate mechanical and thermal functions.
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 battery effectively suppresses both internal resistance increases and temperature rises during internal shorts, demonstrating improved performance by maintaining ion permeability and controlling temperature effectively.
Implementation Method 1
the heat-resistant layer includes heat-resistant particles having at least a surface including a metal compound... suppression of the temperature rise of a battery upon internal short
Implementation Method 2
the heat-resistant layer has a porosity of 25% to 55%... ion permeability to thereby suppress an increase in internal resistance
Data Source
AI summary
A non-aqueous electrolyte secondary battery according to one aspect of the present application comprises: a positive electrode; a negative electrode; a heat-resistant layer that is formed on at least one of the positive electrode and the negative electrode; and a non-aqueous electrolyte, wherein the heat-resistant layer includes heat-resistant particles, at least the surface of said heat-resistant particles comprising a metal compound, the average thickness of the heat-resistant layer is within the range 0.5 μm-5 μm, the porosity of the heat-resistant layer is 25%-55%, the average surface roughness (Ra) of the heat-resistant layer is 0.35 μm or less, and the electronegativity of metal ions of the metal compound is 13.5 or greater.