Dual-Conductive Material Positive Electrode for Battery Resistance
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries experience increased resistance during high-rate charging and discharging due to variations in electrolyte distribution within the positive electrode composite material layer, caused by conductive materials with high DBP oil absorption numbers, which either retain too much electrolyte or allow it to flow out excessively.
Innovation Solution
A dual-conductive material approach is employed, where a first conductive material with a high DBP oil absorption number is used within the composite particle to retain electrolyte and a second conductive material with a lower DBP oil absorption number is applied on the surface to facilitate electrolyte flow, maintaining adequate electrolyte quantity and uniform distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a conductive material with a large DBP oil absorption number is used in the positive electrode composite material layer, then the electrolyte is easily retained near the positive electrode active material, but variations occur in distribution of the electrolyte in the in-plane direction
Solution Approach 1:
The patent applies local quality by using two types of conductive materials with different DBP oil absorption numbers in different locations within the positive electrode composite material layer. Specifically, a first conductive material with a larger DBP oil absorption number is used in certain regions to enhance electrolyte retention, while a second conductive material with a smaller DBP oil absorption number is used in other regions to maintain electrolyte distribution uniformity. This spatial differentiation of material properties resolves the contradiction between electrolyte retention and distribution uniformity.
Solution Approach 2:
The patent employs composite materials by combining two different conductive materials (with different DBP oil absorption numbers) within the same positive electrode composite material layer. This composite approach allows the system to simultaneously achieve both electrolyte retention enhancement and distribution uniformity maintenance, as each material type contributes its specific property to the overall performance of the electrode layer.
2Quantity of substance
If a conductive material with a large DBP oil absorption number is used, then the electrolyte is easily absorbed by the conductive material, but the electrolyte flows out excessively from the positive electrode composite material layer
Solution Approach 1:
The patent uses local quality by positioning conductive materials with different DBP oil absorption numbers in specific regions of the positive electrode composite material layer. The first conductive material with larger DBP oil absorption number is placed in regions where electrolyte absorption is needed, while the second conductive material with smaller DBP oil absorption number is placed in regions where electrolyte loss prevention is critical. This spatial arrangement allows simultaneous achievement of electrolyte absorption and loss prevention.
Solution Approach 2:
The patent applies composite materials by integrating two different conductive materials with contrasting DBP oil absorption characteristics into the same positive electrode composite material layer. This composite structure enables the system to balance electrolyte absorption and retention, where one material type provides absorption capability while the other provides retention capability, thereby resolving the contradiction between electrolyte absorption and loss prevention.
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 configuration effectively suppresses the increase in resistance during high-rate cycles by ensuring sufficient electrolyte retention and preventing excessive loss, thereby maintaining battery performance.
Implementation Method 1
the electrolyte is easily retained near the positive electrode active material adjacent to the conductive material because the conductive material absorbs the electrolyte easily
Implementation Method 2
a second conductive material arranged on a surface of the composite particle and having a DBP oil absorption number smaller than that of the first conductive material
Data Source
AI summary
A non-aqueous electrolyte secondary battery includes a positive electrode composite material layer, the positive electrode composite material layer including: a composite particle including a positive electrode active material, a first conductive material and a binder; and a second conductive material arranged on a surface of the composite particle and having a DBP oil absorption number smaller than that of the first conductive material.