Composite Electrode Particles for Crack-Resistant Dry Battery Forming
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Solution Overview
Problem
Conventional composite particles used in dry forming of electrodes for secondary batteries face issues with flexibility, leading to cracking of electrode active material and deterioration of battery characteristics such as initial capacity and preservation stability, especially during the winding process.
Innovation Solution
The use of composite particles with specific area circularity and porosity ranges, optionally including a conductive additive, to enhance electrode flexibility and improve battery characteristics through dry forming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional composite particles are used in dry forming of electrodes, then the electrode can be formed, but the electrode flexibility deteriorates and cracking occurs during winding
Solution Approach 1:
The patent applies parameter changes by precisely controlling the area circularity (0.70-0.95) and porosity (60-80%) of composite particles. These parameter optimizations enable the particles to deform appropriately during pressure forming without causing cracking, thereby improving both electrode flexibility and cracking resistance simultaneously.
Solution Approach 2:
The patent uses composite particles composed of electrode active material and binder in specific proportions (binder content 1-10 mass%). This composite structure provides both the necessary mechanical flexibility and structural integrity to prevent cracking during electrode formation and winding processes.
2Ease of manufacture
If excessive pressing pressure is applied during pressure forming, then the electrode mixed material layer is formed, but cracking of electrode active material occurs and battery characteristics deteriorate
Solution Approach 1:
The patent changes the physical parameters of composite particles (area circularity and porosity) to enable effective pressure forming at moderate pressures. The optimized porosity (60-80%) allows particles to rearrange and densify under pressure without causing internal stress concentrations that lead to cracking.
Solution Approach 2:
The patent performs preliminary optimization of composite particle properties before pressure forming. By pre-controlling the area circularity and porosity of particles, the electrode mixed material layer can be formed with reduced pressing pressure, preventing cracking before it occurs during the forming process.
3Strength
If composite particles with high porosity are used, then electrode flexibility improves, but manufacturing precision may be affected
Solution Approach 1:
The patent simultaneously optimizes multiple parameters (area circularity: 0.70-0.95 and porosity: 60-80%) to achieve a balance between electrode flexibility and manufacturing precision. This multi-parameter control ensures particles maintain uniformity for precise manufacturing while providing sufficient flexibility for electrode deformation during winding.
Data Source
Figure 1
AI summary
Provided are composite particles that can improve flexibility of an electrode and can cause a secondary battery to display excellent battery characteristics. The composite particles are used in dry forming of an electrode for a secondary battery and contain an electrode active material and a binder. The composite particles have an area circularity of not less than 0.50 and not more than 0.93 and have a porosity of not less than 65% and not more than 80%.