Negative Electrode Fiber Layout for Electrolyte Distribution in Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Non-aqueous electrolyte secondary batteries face issues with ununiformed electrolyte liquid distribution due to expansion and contraction during charge and discharge, leading to deteriorated battery capacity and charge-discharge cycle characteristics.
Innovation Solution
A non-aqueous electrolyte secondary battery design featuring band-shaped electrodes with a negative electrode mixture layer containing fibrous carbon, where the average fiber length of fibrous carbon in the middle portion is larger than at the edges, improving electrolyte liquid retention and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fibrous carbon is uniformly dispersed in the mixture slurry using two kinds of fibrous carbon having different diameter sizes, then the conductive agent dispersion is improved, but the charge-discharge cycle characteristics are not sufficiently improved due to ununiformed electrolyte liquid distribution
Solution Approach 1:
The patent applies local quality by creating different fibrous carbon fiber length distributions in different regions of the negative electrode mixture layer. Specifically, the middle portion contains fibrous carbon with a first average fiber length, while the edge portions contain fibrous carbon with a second average fiber length that is different from the first. This regional differentiation addresses the uniformity problem by tailoring the conductive network and electrolyte retention properties to the specific functional requirements of different electrode regions, thereby improving charge-discharge cycle characteristics.
Solution Approach 2:
The patent employs asymmetry by intentionally creating an asymmetric distribution of fibrous carbon fiber lengths across the electrode width. The edge portions have a different fibrous carbon configuration compared to the middle portion, breaking the symmetric uniformity. This asymmetric design allows the edge portions to better retain electrolyte liquid during charge-discharge cycles, preventing ununiformed distribution and improving overall battery reliability and cycle life.
2Duration of action of moving object
If the electrode assembly expands and contracts during charge and discharge, then the battery operates normally, but the electrolyte liquid distribution becomes ununiformed and battery capacity deteriorates
Solution Approach 1:
The patent applies beforehand cushioning by pre-configuring the fibrous carbon distribution in the negative electrode mixture layer to anticipate and compensate for the effects of electrode expansion and contraction during charge-discharge cycles. The specific arrangement of fibrous carbon with different average fiber lengths in different regions creates a structure that beforehand prevents electrolyte liquid from becoming ununiformed during operation, thus cushioning against capacity deterioration before it occurs.
Solution Approach 2:
The patent uses local quality by designing region-specific fibrous carbon properties in the negative electrode. The middle portion and edge portions have different fibrous carbon average fiber lengths, creating localized properties that address the specific stress and electrolyte distribution challenges each region faces during expansion and contraction. This localized optimization maintains battery capacity and prevents deterioration over multiple cycles.
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
This design enhances charge-discharge cycle characteristics by inhibiting electrolyte outflow during charge and facilitating its return during discharge, resulting in improved battery performance.
Implementation Method 1
the negative electrode mixture layer contains a negative electrode active material and fibrous carbon
Implementation Method 2
an average fiber length of the fibrous carbon contained in a middle portion in a width direction of the negative electrode mixture layer is larger than an average fiber length of the fibrous carbon contained in both edge portions in the width direction of the negative electrode mixture layer
Data Source
AI summary
A non-aqueous electrolyte secondary battery according to an aspect of the present disclosure comprises: an electrode body obtained by winding a positive electrode and a negative electrode with a separator therebetween; an electrolytic solution; and an exterior body that houses the electrode body and the electrolytic solution. The negative electrode has: a negative electrode current collector; and a negative electrode mixture layer formed on the surface of the negative electrode current collector, wherein the negative electrode mixture layer contains a negative electrode active material and fibrous carbon, and the average fiber length of the fibrous carbon contained in the central part of the negative electrode mixture layer in the width direction is greater than the average fiber length of the fibrous carbon contained in both end parts of the negative electrode mixture layer in the width direction.