Silicon Clathrate Electrode Material With Void-Controlled Swelling
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Solution Overview
Problem
The large volume change of silicon (Si) during charge and discharge degrades the electrode function in batteries, particularly in applications like battery electric vehicles (BEV), plug-in hybrid electric vehicles (PHEV), and hybrid electric vehicles (HEV).
Innovation Solution
An electrode active material comprising a silicon clathrate II type crystal phase with controlled voids, specifically a void amount of 0.015 cc/g to 0.05 cc/g for pore diameters of 5 nm or less, is introduced to mitigate volume change during charge and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If silicon is used as electrode active material to achieve high energy density, then battery energy density is improved, but volume change during charge and discharge increases causing electrode function degradation
Solution Approach 1:
The patent applies porous materials by introducing voids with specific pore diameters (5 nm or less, 10 nm or less, 100 nm or less) into the silicon clathrate II structure. These voids act as buffer spaces that accommodate volume expansion during lithiation, preventing structural collapse and maintaining electrode function stability while preserving high energy density
Solution Approach 2:
The patent changes physical parameters by precisely controlling void amounts at different pore diameter ranges. By optimizing void amount P1 (0.015-0.05 cc/g for 5 nm or less), P2 (0.03-0.08 cc/g for 10 nm or less), and P3 (0.1-0.5 cc/g for 100 nm or less), the invention achieves both high energy density and reduced volume change, resolving the contradiction between energy density and reliability
2Reliability
If void amount of small pore diameter (5 nm or less) is increased to reduce volume change, then electrode stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent transforms a qualitative control problem into a quantitative one by specifying precise parameter ranges for void amounts at different pore diameter scales. The multi-scale void amount parameters (P1, P2, P3) provide clear manufacturing targets that balance electrode stability with achievable manufacturing precision
Solution Approach 2:
The patent segments the void structure into three distinct pore diameter ranges (5 nm or less, 10 nm or less, 100 nm or less) with independently optimized void amounts. This segmentation allows precise control of each scale's contribution to volume change, making the overall void structure manufacturable while maintaining electrode stability
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 electrode active material with controlled voids reduces volume change, enhancing the stability and performance of batteries by inhibiting crashing and allowing for reduced restraining pressure, thus improving energy density and cycle life.
Implementation Method 1
a void is included inside a primary particle; and a void amount P1 of a void with a pore diameter of 5 nm or less is 0.015 cc/g or more and 0.05 cc/g or less
Data Source
AI summary
A main object of the present disclosure is to provide an electrode active material of which volume change due to charge and discharge is small. The present disclosure achieves the object by providing an electrode active material including a silicon clathrate II type crystal phase, wherein a void is included inside a primary particle; and a void amount P1 of a void with a pore diameter of 5 nm or less is 0.015 cc/g or more and 0.05 cc/g or less.