Nonaqueous Secondary Battery Electrode Layout for Electrolyte Permeation
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Solution Overview
Problem
Existing nonaqueous electrolyte secondary batteries face challenges in achieving balanced capacity ratios between positive and negative electrodes, leading to poor electrolyte permeation and potential precipitation of charge carriers, which deteriorates battery performance.
Innovation Solution
The battery design includes a configuration where the negative electrode active material layer has a smaller basis weight and thickness at the area opposed to the positive electrode, with a gradual reduction towards the end, forming an inclined gap and enhancing electrolyte permeation, while maintaining a balanced capacity ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the density of active material layer is increased to achieve higher capacity, then the capacity is improved, but the electrolyte permeation is deteriorated
Solution Approach 1:
The patent applies local quality by creating a gradient in the active material layer density, where the end portion has a lower density than the central portion. This allows the end portion to facilitate electrolyte permeation while the central portion maintains high capacity, resolving the contradiction between overall capacity and local electrolyte injection properties.
Solution Approach 2:
The patent changes the density parameter of the active material layer along the length direction, creating a gradient structure where density decreases from the central portion to the end portion. This parameter variation enables both high capacity retention and improved electrolyte permeation at the injection site.
2Quantity of substance
If the capacity of negative electrode is increased to match positive electrode, then the capacity balance is improved, but the risk of charge carrier precipitation increases
Solution Approach 1:
The patent applies local quality by creating a gradient in the active material layer density, where the end portion has a lower density than the central portion. This allows the end portion to facilitate electrolyte permeation while the central portion maintains high capacity, resolving the contradiction between overall capacity and local electrolyte injection properties.
Solution Approach 2:
The patent changes the density parameter of the active material layer along the length direction, creating a gradient structure where density decreases from the central portion to the end portion. This parameter variation enables both high capacity retention and improved electrolyte permeation at the injection site.
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 facilitates improved electrolyte injection properties and prevents charge carrier precipitation, ensuring better battery performance by optimizing the capacity ratio and liquid injection efficiency.
Implementation Method 1
it is facilitated to make the nonaqueous electrolyte permeate from the first area side to the inside of the electrode assembly
Implementation Method 2
the thickness of the negative electrode active material layer being gradually smaller toward the end side... forming an inclined gap and enhancing electrolyte permeation
Data Source
AI summary
The herein disclosed nonaqueous electrolyte secondary battery includes an electrode assembly in which a positive electrode including positive electrode active layers, a negative electrode including negative electrode active layers, and a separator are provided. The negative electrode active material layer includes a first area between an end side and a position 5 mm away from the end side in the width direction. An end part of the positive electrode is opposed to at least a part of the first area. A thickness T1 at a central part of the positive electrode and a thickness T2 at the end part of the positive electrode satisfy 0.95<T2/T1<1.05. Regarding the negative electrode active material layer, a basis weight M1 at a central part of the negative electrode and a basis weight M2 of an area opposed to the positive electrode active material layer of the first area satisfy 0.95<M2/M1<1.