Non-Aqueous Secondary Battery Electrode Insulation for Short-Circuit Control
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Solution Overview
Problem
The existing non-aqueous electrolyte secondary batteries face challenges in reliably suppressing short circuits between the positive and negative electrodes, leading to increased costs and manufacturing time, while also risking battery resistance and volumetric capacity decreases due to excessive insulating layer usage.
Innovation Solution
A non-aqueous electrolyte secondary battery configuration featuring a positive electrode with a current collector, active material layer, and insulating layers, where the insulating layer is strategically positioned along the end portion of the positive electrode active material layer and separated from the negative electrode active material layer, ensuring effective short circuit prevention without excessive layer thickness or binder content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer is provided to overlap an end portion of a positive electrode active material layer from a surface of a current collector to suppress short circuit, then short circuit prevention is improved, but manufacturing cost and manufacturing time increase
Solution Approach 1:
The insulating layer is applied selectively only at the end portion of the positive electrode active material layer where short circuit risk is highest, rather than covering the entire electrode surface. This localized application reduces binder content and manufacturing complexity while maintaining effective short circuit prevention at the critical area.
Solution Approach 2:
The insulating layer is applied with partial coverage rather than complete coverage of the electrode. By applying the insulating layer only where needed (at the end portion), the patent achieves sufficient short circuit prevention without the excessive binder content and manufacturing burden that would result from full-surface application.
2Reliability
If an insulating layer is provided to suppress short circuit between positive and negative electrodes, then reliability is improved, but battery resistance increases
Solution Approach 1:
The insulating layer is positioned only at the end portion of the positive electrode active material layer, avoiding coverage of the main active material area. This localized placement prevents short circuits at the vulnerable end region while minimizing the insulating barrier effect on ion transport in the active material region, thus reducing overall battery resistance.
3Reliability
If an insulating layer is provided to suppress short circuit, then safety is improved, but volumetric capacity ratio decreases
Solution Approach 1:
The insulating layer is applied selectively at the end portion of the positive electrode active material layer rather than across the entire electrode surface. This localized application provides safety against short circuits at the critical end region while minimizing the volume occupied by non-active insulating material, thus preserving the volumetric capacity ratio.
4Reliability
If an insulating layer with fine crack is used to suppress desorption and short circuit, then reliability is improved, but the insulating layer requires large amount of binder and specific thickness
Solution Approach 1:
The insulating layer is applied only at the end portion of the positive electrode active material layer where short circuit and desorption risks are concentrated. This localized application reduces the total quantity of binder and insulating material required while maintaining effective protection at the critical region.
Solution Approach 2:
The insulating layer is applied with partial coverage at the end portion rather than complete coverage. This partial application reduces the total binder content and layer thickness requirements while providing sufficient protection against desorption and short circuit at the vulnerable end region.
Data Source
AI summary
A non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and a non-aqueous electrolyte. The positive electrode includes a positive electrode current collector, a positive electrode active material layer on a part of a surface of the positive electrode current collector containing a positive electrode active material, and an insulating layer on other parts of the surface of the positive electrode current collector containing an inorganic filler. The negative electrode includes a negative electrode current collector, and a negative electrode active material layer on a part of a surface of the negative electrode current collector containing a negative electrode active material. The insulating layer includes a first insulating layer disposed along an end portion of the positive electrode active material layer, and a second insulating layer formed at a position separated from the first insulating layer and facing an end portion of the negative electrode active material layer.