Secondary Battery Anode Particle Structure for Energy Density and Rate
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Solution Overview
Problem
Secondary batteries face challenges in achieving high energy density while maintaining good rate performance, as increasing energy density often compromises rate performance.
Innovation Solution
A secondary battery design incorporating a negative electrode plate with a carbon-based material and a silicon-based material, both featuring secondary particles formed by aggregation of primary particles, which increases ion intercalation channels and reduces impedance at the negative electrode-electrolyte interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the energy density of secondary batteries is increased, then the energy storage capacity is improved, but the rate performance deteriorates
Solution Approach 1:
The negative electrode active material is segmented into primary particles that aggregate to form secondary particles with controlled size distribution (Dv10, Dv50, Dv90). This segmentation creates multiple ion intercalation channels within each secondary particle, allowing simultaneous achievement of high energy density through compact packing and good rate performance through enhanced ion transport pathways.
Solution Approach 2:
The patent applies local quality by creating a heterogeneous particle size distribution within the secondary particles, where different regions have different characteristics. The Dv10, Dv50, and Dv90 parameters define specific size ranges that create local variations in ion diffusion paths, enabling optimized performance at different locations within the electrode structure.
2Quantity of substance
If the particle size of silicon-based material is increased, then the energy density is improved, but the rate performance deteriorates due to longer ion diffusion paths
Solution Approach 1:
The silicon-based material is divided into primary particles that aggregate into secondary particles with controlled size distribution. The Dv50 is specifically controlled to be 5 μm to 15 μm, creating an optimal balance where the secondary particles are large enough for high energy density but contain internal structures that provide short ion diffusion paths through their aggregated primary particle composition.
Solution Approach 2:
The negative electrode uses a composite structure of carbon-based material and silicon-based material, both forming secondary particles through aggregation of primary particles. This composite approach combines the high capacity of silicon with the stable structure of carbon, while the secondary particle morphology optimizes both energy density and rate performance.
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 both high energy density and improved rate performance by optimizing the particle structure and proportion of secondary particles in the carbon-based and silicon-based materials.
Implementation Method 1
increasing ion intercalation channels and reducing impedance of a negative electrode-electrolyte interface
Data Source
AI summary
This application provides a secondary battery and an electric apparatus. The secondary battery includes a negative electrode plate. The negative electrode plate includes a negative electrode current collector, and a negative electrode film layer that is provided on at least one surface of the negative electrode current collector and includes a negative electrode active material. The negative electrode active material includes a carbon-based material and a silicon-based material. The carbon-based material includes secondary particles formed by aggregation of primary particles. The silicon-based material includes secondary particles formed by aggregation of primary particles.