Negative Electrode Plate Binder Gradient for Lower DC Resistance
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Solution Overview
Problem
Existing negative electrode plates in secondary batteries suffer from uneven binder distribution and aggregation, leading to increased direct current resistance and impaired electrical performance, which are not suitable for the demands of new generation electrochemical systems.
Innovation Solution
A negative electrode plate design with a controlled mass ratio of binder in specific regions, combined with electromagnetic induction heating to reduce binder aggregation, thereby improving intercalation and deintercalation of metal ions and reducing direct current resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the binder distribution in the negative electrode film layer is uniform, then the binding performance is improved, but the direct current resistance increases and electrical performance deteriorates
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 (closer to the current collector) has a binder mass ratio of 5-15%, while the second region (farther from the current collector) has a binder mass ratio of 3-10%. This regional differentiation allows the binder to provide adequate binding performance where needed while reducing aggregation and direct current resistance in other areas, thus resolving the technical contradiction between binding performance and electrical performance.
2Object-generated harmful factors
If the binder aggregation is reduced, then the direct current resistance decreases and electrical performance improves, but the binding performance may be compromised
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through spatially varying binder distribution. The first region near the current collector maintains a higher binder mass ratio (5-15%) to ensure adequate binding performance, while the second region farther away has a lower binder mass ratio (3-10%) to reduce aggregation and direct current resistance. This localized optimization allows the electrode to achieve both good binding performance and low direct current resistance simultaneously.
3Productivity
If the mass ratio of binder in the first region to the second region is controlled within 0.6-1.0, then the binder aggregation is effectively reduced and kinetic performance is improved
Solution Approach 1:
The patent applies parameter changes by precisely controlling the binder mass ratio parameter in different regions. The first region has a binder mass ratio of 5-15% and the second region has 3-10%, resulting in a mass ratio between 0.6-1.0. This parameter optimization effectively reduces binder aggregation and improves kinetic performance while maintaining manufacturability through controlled distribution.
4Object-generated harmful factors
If electromagnetic induction heating is applied to remove binder from the first region, then the binder aggregation is reduced and direct current resistance decreases, but the process complexity increases
Solution Approach 1:
The patent replaces traditional mechanical or chemical binder removal methods with electromagnetic induction heating. This thermal field approach selectively removes binder from the first region through controlled heating, effectively reducing binder aggregation and direct current resistance. The electromagnetic induction heating provides a more precise and controllable method compared to conventional approaches, though it does increase process complexity.
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
The controlled binder ratio and electromagnetic induction heating effectively reduce binder aggregation, enhancing kinetic performance, cycling performance, and lowering direct current resistance in secondary batteries.
Implementation Method 1
The electromagnetic induction heating can effectively remove part of the binder in the first region, which can not only reduce the aggregation of the binder in the first region to thus reduce the direct current resistance of the battery
Data Source
AI summary
A 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. The negative electrode film layer comprises a binder. The negative electrode film layer comprises a first region and a second region. 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 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, and the second region 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. h represents a thickness of the negative electrode film layer.