Thin Sn Si Anode for Rapid Charging
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Solution Overview
Problem
Lithium secondary batteries, particularly those intended for automotive use, face challenges in enabling rapid charging due to the low Li storage capacity of conventional anode active materials like carbon graphite, and existing Sn or Sn alloy-based solutions do not effectively support high-rate charging.
Innovation Solution
An anode active material with a metallic part comprising Sn or Si, having a film thickness of 0.05 μm or less, which facilitates rapid Li ion diffusion and is preferably in a flaky form with a carbon coat to enhance electrical conductivity and reduce internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional carbon materials (graphite) are used as anode active materials, then the battery structure is simple and manufacturing is easy, but the Li storage capacity is low and rapid charging is not enabled
Solution Approach 1:
The patent changes the film thickness parameter of the metallic coating to 0.05 μm or less, which is a critical threshold that enables rapid Li ion diffusion while maintaining structural integrity. This parameter change transforms the charging rate from limited to high, resolving the contradiction between storage capacity and charging speed.
Solution Approach 2:
The patent creates a composite structure with a current collector substrate and a thin metallic coating layer (Sn, Si, or their alloys). This composite design combines the mechanical strength of the substrate with the high Li storage capacity and rapid diffusion properties of the thin metallic layer, achieving both high capacity and fast charging.
2Quantity of substance
If Sn or Sn alloy films with larger thickness (2-30 μm) are formed to increase Li storage capacity, then the Li storage capacity improves, but the charging rate decreases and rapid charging becomes infeasible
Solution Approach 1:
The patent identifies and applies a critical threshold parameter change by reducing the metallic coating thickness to 0.05 μm or less. This specific thickness range allows Li ions to diffuse rapidly through the coating while still providing sufficient Li storage capacity, thereby achieving both high capacity and fast charging simultaneously.
3Speed
If the metallic part film thickness is reduced to 0.05 μm or less to enable rapid charging, then the Li ion diffusion speed increases, but the manufacturing precision requirement increases
Solution Approach 1:
The patent establishes a specific parameter range (0.05 μm or less) that balances manufacturing feasibility with performance requirements. By defining this clear threshold, the patent makes it possible to control film thickness within achievable manufacturing tolerances while ensuring rapid Li ion diffusion and high charging rates.
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 anode active material enables high-rate charging and increased Li storage capacity, making lithium secondary batteries suitable for rapid charging applications while reducing internal resistance and enhancing output.
Implementation Method 1
By sufficiently reducing the film thickness of the anode active material, Li ions can easily spread
Data Source
AI summary
The principal object of the present invention is to provide an anode active material suitable for rapid charging. The present invention provides an anode active material comprising a metallic part which comprises Sn or Si and has a film thickness of 0.05 μm or less, and thereby solving the problem.