Li-Ion Battery Anode Composition for Fast Charging Without Lithium Plating
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Solution Overview
Problem
Current lithium-ion batteries with graphite, soft carbon, hard carbon, or Si-C negative materials have limited fast charging ability and safety concerns due to lithium plating, necessitating the development of a more efficient fast charging solution.
Innovation Solution
A fast charging lithium-ion battery design featuring a positive electrode plate, a negative electrode plate with titanium niobium oxide or lithium titanate as negative active material, and a separator, where the negative active material layer's effective area to thickness ratio is greater than 2×10^5 mm, enhancing electron/ion transmission and conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If graphite, soft carbon, hard carbon, or Si-C composite material is used as negative electrode material, then the battery can be manufactured with conventional materials and processes, but the fast charging ability is limited to 3C to 5C and lithium plating occurs causing safety concerns
Solution Approach 1:
The patent changes the material parameter of the negative electrode from conventional graphite/carbon materials to lithium titanate (Li4Ti5O12) or titanium niobium oxide, which fundamentally alters the charging rate capability from 3-5C to 10C or higher while maintaining manufacturability through established battery assembly processes
Solution Approach 2:
The patent employs composite negative electrode materials combining lithium titanate and titanium niobium oxide in specific weight ratios (70:30 to 30:70), creating a material system that leverages the complementary properties of both materials to achieve enhanced fast charging performance and structural stability
2Device complexity
If conventional negative electrode materials are used, then the battery structure can be kept simple and manufacturing processes remain straightforward, but lithium plating occurs causing safety concerns and reduced reliability
Solution Approach 1:
The patent changes the electrochemical potential parameter of the negative electrode material to a higher level (lithium titanate and titanium niobium oxide have higher potentials than graphite), which prevents lithium plating by maintaining a more favorable potential difference during charging, thereby improving safety without increasing structural complexity
Solution Approach 2:
The patent converts the typically harmful effect of low potential in graphite electrodes (which causes lithium plating) into a benefit by selecting materials with higher potentials, thereby eliminating the safety hazard of lithium plating while maintaining the simple battery structure and conventional manufacturing approach
3Quantity of substance
If the negative active material layer thickness is increased to maintain capacity, then the battery capacity is improved, but the fast charging ability deteriorates due to longer ion transport paths
Solution Approach 1:
The patent changes the material composition parameter to lithium titanate and titanium niobium oxide, which have superior ionic conductivity and electrochemical activity, allowing the negative electrode to achieve both high capacity and fast charging capability simultaneously by reducing the effective ion transport resistance even at optimal thicknesses
Solution Approach 2:
The patent employs porous or granular structures of lithium titanate and titanium niobium oxide in the negative electrode layer, which provide extensive surface area and shortened ion transport paths, enabling both high capacity (through increased active material content) and fast charging (through reduced diffusion distances) to coexist
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
This design enables faster charging and discharging rates while maintaining high capacity retention, addressing the limitations of existing batteries and enhancing market competitiveness.
Implementation Method 1
The material of the negative active material layer includes titanium niobium oxide, lithium titanate or a combination thereof
Implementation Method 2
the negative active material layer's effective area to thickness ratio is greater than 2×10^5 mm, enhancing electron/ion transmission and conduction
Data Source
Figure 1A~1B
Figure 1C
Figure 2A~2B
AI summary
A fast charging lithium-ion battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. The positive electrode plate includes a positive current collector and a positive active material layers. The negative electrode plate includes a negative current collector and negative active material layers. The negative active material layers include titanium niobium oxide, lithium titanate, or a combination thereof. The separator is disposed between the positive electrode plate and the negative electrode plate. The electrolyte contacts the positive electrode plate and the negative electrode plate. The negative active material layers have an effective area corresponding to the positive electrode plate. The negative active material layers have a thickness on one surface of the negative current collector. A ratio of the effective area to the thickness is greater than 2×105mm.