Lithium Battery Anode Composite for High Output and Cycle Life
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Solution Overview
Problem
Conventional lithium secondary batteries, particularly those used in electric vehicles and hybrid electric vehicles, face challenges in achieving high-output characteristics and energy density while maintaining low-temperature stability, as they often rely on graphite anode materials with poor output properties and amorphous carbon with low energy density.
Innovation Solution
A high-output lithium secondary battery design incorporating a cathode active material with a layered structure and specific particle diameter, combining crystalline graphite and amorphous carbon as anode active materials, along with a high-ion permeability separator, to enhance energy density and output characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional graphite is used as anode active material, then excellent cycle lifespan is achieved, but poor output properties result
Solution Approach 1:
The patent combines crystalline graphite and amorphous carbon as anode active materials in a composite structure. The crystalline graphite provides excellent cycle lifespan through uniaxial orientation of graphene layers, while amorphous carbon contributes high output properties and energy density. This merging of two different carbon structures resolves the contradiction between cycle lifespan and output properties.
2Quantity of substance
If amorphous carbon is used as anode active material, then high energy density is achieved, but energy density remains less than 300 mAh/g
Solution Approach 1:
The patent employs a composite anode material consisting of crystalline graphite and amorphous carbon. The amorphous carbon component provides high energy density capacity, while the crystalline graphite component ensures reliable output characteristics and structural stability. This composite material approach allows the anode to achieve both high energy density and reliable output characteristics simultaneously.
3Power
If high-output characteristics are pursued for EVs and HEVs, then high output within short period is achieved, but energy density and low-temperature stability are compromised
Solution Approach 1:
The patent applies local quality by using different cathode active materials with specific particle diameter ranges (0.03 to 0.1 μm/mAh) optimized for different functions. The layered structure cathode material provides high output characteristics, while the specific particle size distribution maintains energy density. Additionally, the composite anode with crystalline graphite and amorphous carbon in specific ratios ensures both high-output characteristics and energy density.
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 high energy density and output characteristics suitable for electric vehicles and hybrid electric vehicles, with improved cycle life and stability, while maintaining energy density comparable to conventional lithium secondary batteries.
Implementation Method 1
a cathode including a cathode active material having an average particle diameter (with respect to capacity) of 0.03 to 0.1 μm/mAh... represented by Formula 1... Li x (Ni v Mn w Co y M z )O 2-t A t
Implementation Method 2
a separator
Implementation Method 3
an anode including crystalline graphite and amorphous carbon as anode active materials... exhibits very reversible charge/discharge behavior due to uniaxial orientation of a graphene layer
Data Source
Figure 1(a)~1(b)
AI summary
Disclosed is a high-output lithium secondary battery including: a cathode including a cathode active material having an average particle diameter (with respect to capacity) of 0.03 to 0.1 µm/mAh and a layered structure; an anode including crystalline graphite and amorphous carbon as anode active materials, wherein the amount of the amorphous carbon is between 40 and 100 wt% based on the total weight of the anode active materials; and a separator.