Li-Ion Battery Electrode Insulating Layer with Electrolyte Buffer Holes
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Solution Overview
Problem
The formation of an insulating layer on the mixture layer in lithium ion secondary batteries decreases electrolyte liquid permeability, leading to decreased battery responsiveness and output due to inconsistent Li-ion concentration and increased resistance.
Innovation Solution
Incorporating holes (puddles) in the interface between the insulating layer and the mixture layer, specifically with ceramic particles, to maintain electrolyte replaceability and concentration near the active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer is formed on the mixture layer to prevent internal short-circuit spread, then safety is improved, but liquid permeability decreases and battery responsiveness deteriorates
Solution Approach 1:
The insulating layer is designed with a porous structure containing holes having diameters of 2.5 μm or more. These pores allow electrolyte to penetrate through the insulating layer while maintaining its insulating function, thus resolving the contradiction between safety and liquid permeability.
Solution Approach 2:
The insulating layer is formed as a composite structure combining insulating resin material with ceramic particles. This composite structure provides both the insulating properties for safety and controlled porosity for electrolyte permeability, addressing the contradiction between reliability and productivity.
2Reliability
If an insulating layer is formed on the mixture layer to prevent internal short-circuit spread, then safety is improved, but electrolyte replaceability decreases due to reduced liquid permeability
Solution Approach 1:
The insulating layer incorporates pores with diameters of 2.5 μm or more that enable electrolyte to flow through and replace itself effectively. This porous structure maintains electrolyte replaceability while the insulating material ensures safety against internal short-circuit spread.
Solution Approach 2:
The porous insulating layer acts as an intermediary structure that allows electrolyte molecules to pass through while blocking the spread of internal short-circuits. The pores serve as channels for electrolyte replacement without compromising the insulating barrier function.
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
Ensures constant Li-ion concentration, enhancing battery output and responsiveness by acting as a buffer for fresh electrolyte, thereby improving battery performance.
Implementation Method 1
providing holes (puddles) in an interface between an insulating layer and a mixture layer... the holes (puddles) provided in the surface of the mixture layer play a role of a buffer that stores the fresh (before reaction) electrolyte
Data Source
AI summary
It is an object to provide a lithium ion secondary battery that ensures a replaceability of an electrolyte in a proximity of an active material and is excellent in output and responsiveness. The lithium ion secondary battery includes an electrode that includes a negative electrode foil, a negative electrode mixture layer disposed on a surface of the negative electrode foil, and an insulating layer disposed on a surface of the negative electrode mixture layer. The insulating layer contains ceramic particles. On the surface of the negative electrode mixture layer facing a border between the insulating layer and the negative electrode mixture layer, a plurality of holes (puddles) having diameters of 2.5 μm or more are provided.