Li-Ion Battery Heat Suppression via Particle Diameter Control
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in suppressing heat generation during short-circuiting while maintaining high output characteristics, particularly in vehicle applications where low electric resistance materials are used.
Innovation Solution
A lithium ion secondary battery design incorporating a negative electrode with a mixture of graphite and amorphous carbon particles and a positive electrode with a lithium composite oxide (LixNiyMnzCo(1-y-z)O2) having a specific layer crystal structure and controlled particle diameter, which helps in maintaining internal resistance and output characteristics, thereby effectively suppressing heat generation during short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a material with low electric resistance is used to improve output characteristic, then the output characteristic is improved, but heat generation during short-circuiting increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle diameter of lithium composite oxide within 3.0 μm to 6.0 μm and adjusting the stoichiometric ratios (y+z≤0.5) in the chemical formula LixNiyMnzCo(1-y-z)O2. These parameter optimizations enable the material to achieve low electric resistance for high output while simultaneously suppressing heat generation during short-circuiting through controlled internal resistance
Solution Approach 2:
The patent uses composite materials by combining lithium composite oxide (LixNiyMnzCo(1-y-z)O2) with specific negative electrode materials. This composite approach allows the battery to achieve both low internal resistance for high output characteristics and controlled heat generation during short-circuiting, as the composite structure balances conductivity and thermal management
2Power
If graphite material is used to maintain higher battery voltage, then the lower output at the end stage of discharge is suppressed, but the device complexity increases due to material mixing requirements
Solution Approach 1:
The patent applies parameter changes by optimizing the particle diameter of lithium composite oxide to 3.0 μm to 6.0 μm, which enables effective utilization of the material's electrochemical properties. This parameter control ensures high battery voltage maintenance during discharge while simplifying the mixing process through standardized particle size specifications
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 heat generation during short-circuiting while maintaining high output characteristics, enhancing safety and durability through controlled internal resistance and chemical reaction rates.
Implementation Method 1
a positive electrode including a lithium composite oxide... while the output characteristic of the battery is maintained
Implementation Method 2
In the occurrence of short-circuiting in the battery including the material with low electric resistance, the large current can flow in the battery to generate heat
Data Source
AI summary
A lithium ion secondary battery includes: a negative electrode having a carbon-based negative electrode material containing graphite particles and amorphous carbon particles; and a positive electrode including a lithium composite oxide. The lithium composite oxide is represented by a general formula: LixNiyMnzCo(1-y-z)O2, where x is a numeral of 1 or more and 1.2 or less, and y and z are positive numerals satisfying the relation of y+z<1. The lithium composite oxide has a layer crystal structure and has a median particle diameter (D50) of 4.0 μm or more and less than 6.0 μm.