Negative Electrode Plate Binder Distribution for Battery Resistance
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Solution Overview
Problem
Existing negative electrode plates in secondary batteries suffer from defects that hinder their performance in new generation electrochemical systems, particularly due to uneven binder distribution leading to increased direct current resistance and reduced kinetic performance.
Innovation Solution
A negative electrode plate design with a controlled mass ratio of binder in two distinct regions, where the ratio in the first region is 0.1-1.4, achieved through electromagnetic induction heating, to reduce binder aggregation and maintain binding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the binder is uniformly distributed in the negative electrode film layer, then the binding performance is improved, but the direct current resistance increases due to binder aggregation in the first region
Solution Approach 1:
The patent applies local quality by creating different binder mass ratios in different regions of the negative electrode film layer. Specifically, the first region (outer half) has a binder mass ratio of 0.1-1.4 times that of the second region (inner half), allowing the binder to be concentrated near the current collector for binding performance while reducing binder content at the outer surface to minimize direct current resistance and facilitate ion transport.
2Stability of the object's composition
If the binder content is increased to improve binding performance, then the structural stability is improved, but the kinetic performance deteriorates due to reduced ion intercalation and deintercalation efficiency
Solution Approach 1:
The patent implements local quality by spatially varying the binder distribution: the second region (inner half) maintains higher binder content to ensure structural stability and binding performance near the current collector, while the first region (outer half) has reduced binder content to minimize obstruction of ion transport pathways, thereby improving kinetic performance and ion intercalation/deintercalation efficiency.
3Object-affected harmful factors
If the binder is concentrated in the first region to reduce direct current resistance, then the electrical performance is improved, but the binding performance deteriorates
Solution Approach 1:
The patent applies local quality by creating a gradient binder distribution where the binder mass ratio in the first region is controlled at 0.1-1.4 times that of the second region. This ensures that sufficient binder remains in the first region to maintain basic binding performance while significantly reducing binder aggregation compared to uniform distribution, thereby lowering direct current resistance and improving electrical performance.
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 improves kinetic performance and reduces direct current resistance, enhancing the cycling performance of secondary batteries by facilitating better ion intercalation and deintercalation, particularly for lithium ions.
Implementation Method 1
The negative electrode plate is a negative electrode plate treated by electromagnetic induction heating
Implementation Method 2
electromagnetic induction heating can effectively remove part of the binder in the first region
Data Source
Figure 1(a)~2
Figure 3~5
Figure 6~7
AI summary
Provided are a negative electrode plate, a secondary battery, and an electrical apparatus. The negative electrode plate comprises a negative electrode current collector and a negative electrode film layer located on at least one side of the negative electrode current collector, and the negative electrode film layer comprises a binder, wherein the negative electrode film layer comprises a first region and a second region, and the mass ratio of the binder in the first region to the binder in the second region is 0.1-1.4. The first region is a region that extends from a surface on a side of the negative electrode film layer away from the negative electrode current collector towards the interior of the negative electrode film layer by a distance within h/2, the second region is a region that extends from a surface on a side of the negative electrode film layer close to the negative electrode current collector towards the first region by a distance within h/2, and h represents a thickness of the negative electrode film layer.