Lithium Battery Negative Electrode Composite Material
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Solution Overview
Problem
Lithium secondary batteries face limitations in achieving high-current input characteristics, high-temperature storage efficiency, and long-term lifespan due to the low theoretical capacity of graphite used as a negative electrode active material, which hinders the rapid charging and discharging and commercialization of electric vehicles.
Innovation Solution
A lithium secondary battery with a negative electrode active material layer comprising a mixture of graphite particles and low crystalline carbon-based particles, optimized for exothermic peak properties and particle size distribution, allowing for rapid ion adsorption and release, improved high-temperature storage, and extended lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If graphite is used as negative electrode active material, then the battery structure is simple and easy to manufacture, but the charge/discharge rate is slow and high-current input characteristics cannot be realized
Solution Approach 1:
The patent uses a composite negative electrode active material consisting of graphite particles and low crystalline carbon-based particles. The graphite provides structural stability and ease of manufacture, while the low crystalline carbon-based particles enable rapid lithium ion insertion/extraction, achieving high charge/discharge rates and high-current input characteristics.
Solution Approach 2:
The patent optimizes the particle size distribution of both graphite and low crystalline carbon-based particles, controlling their diameter ratios and size ranges to improve lithium ion diffusion kinetics and enable rapid charging/discharging while maintaining manufacturing simplicity.
2Ease of manufacture
If graphite is used as negative electrode active material, then the manufacturing process is simple, but high-temperature storage efficiency deteriorates and lifespan is reduced
Solution Approach 1:
The composite structure combines graphite's structural stability with low crystalline carbon-based particles' superior high-temperature performance. This combination maintains manufacturing simplicity while significantly improving high-temperature storage efficiency and extending battery lifespan.
Solution Approach 2:
The patent creates different local environments within the negative electrode by distributing low crystalline carbon-based particles among graphite particles. This local modification allows different regions to perform different functions: graphite provides structural framework while low crystalline carbon regions provide high-temperature stability and rapid ion transport.
3Device complexity
If graphite is used as negative electrode active material, then the battery structure is simple, but rapid charging and discharging cannot be achieved
Solution Approach 1:
The patent maintains relatively simple battery structure by using a composite negative electrode active material rather than completely redesigning the battery architecture. The low crystalline carbon-based particles enable rapid lithium ion insertion/extraction, achieving fast charging speeds while keeping the overall structure comparable to conventional graphite-based batteries.
4Quantity of substance
If high-capacity negative electrode active material is used, then the driving range increases, but the commercialization time is extended and reliability is reduced
Solution Approach 1:
The patent optimizes particle size parameters and composition ratios of the composite negative electrode active material to achieve a balance between capacity and reliability. The controlled particle size distribution and mixing ratios enable sufficient driving range while maintaining excellent high-temperature storage efficiency and lifespan performance for commercialization.
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 achieves rapid charging and discharging capabilities, maintains capacity at high temperatures, and exhibits excellent lifespan characteristics without compromising energy density, making it suitable for electric vehicles and advancing their commercialization.
Implementation Method 1
the low crystalline carbon-based particles may be capable of adsorbing and releasing Li ions
Implementation Method 2
the negative electrode active material layer has an apex of an exothermic peak in a temperature range of no less than 370° C. and no more than 390° C., as measured by differential scanning calorimetry (DSC)
Data Source
AI summary
Provided is a lithium secondary battery. The lithium secondary battery includes a negative electrode including a negative electrode active material layer, wherein the negative electrode active material layer includes a mixed negative electrode active material including graphite particles and low crystalline carbon-based particles, and the negative electrode active material layer has an apex of an exothermic peak in a temperature range of no less than 370° C. and no more than 390° C., as measured by differential scanning calorimetry (DSC).