Electrode Assembly Polymers for Battery Cycle Stability
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Solution Overview
Problem
The internal resistance of battery cells causes polarization, affecting the cycle performance of batteries, and the use of fluorinated polymers in the negative electrode film layer generates hydrogen ions that reduce the stability of the positive electrode, limiting the effectiveness of improving battery cycle performance.
Innovation Solution
Incorporating a fluorinated polymer in the negative electrode film layer and a nitrile-based polymer material in the positive electrode film layer to form a fluoride-rich SEI film and enhance ion transport, respectively, mitigating the adverse effects of hydrogen ions on the positive electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorinated polymer is used in the negative electrode film layer to form SEI film and reduce polarization, then cycle performance is improved, but hydrogen ions are generated that reduce positive electrode stability
Solution Approach 1:
A nitrile-based polymer material is introduced as an intermediary substance in the positive electrode film layer. This material acts as a mediator that captures hydrogen ions generated by the fluorinated polymer in the negative electrode, preventing them from damaging the positive electrode active material. The nitrile-based polymer serves as a buffer that neutralizes the harmful hydrogen ions while allowing beneficial ion transport to continue.
Solution Approach 2:
The hydrogen ions generated by the fluorinated polymer, which are initially harmful to the positive electrode, are converted into a beneficial effect. The nitrile-based polymer material captures these hydrogen ions, and through synergistic interaction with the fluorinated polymer, transforms this harmful byproduct into a mechanism that enhances overall battery stability and cycle performance.
2Stability of the object's composition
If nitrile-based polymer material is added to the positive electrode film layer to capture hydrogen ions, then positive electrode stability is improved, but device complexity increases
Solution Approach 1:
The nitrile-based polymer material is applied locally and specifically in the positive electrode film layer, where it is most needed to capture hydrogen ions. This localized application targets the specific problem area without requiring comprehensive modification of the entire battery structure, thereby minimizing the increase in overall device complexity while achieving the desired stability improvement.
3Reliability
If fluorinated polymer is used to enhance ionic conductivity, then polarization is reduced, but hydrogen ions are generated that adversely affect the positive electrode interface
Solution Approach 1:
The nitrile-based polymer material serves as an intermediary layer at the positive electrode interface that captures hydrogen ions before they can cause adverse effects. This mediator substance allows the fluorinated polymer to continue enhancing ionic conductivity in the negative electrode while protecting the positive electrode interface from hydrogen ion damage.
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 synergistic effect improves ion transport performance at both electrode interfaces, stabilizes the positive electrode active material, and enhances the overall cycle performance of the battery.
Implementation Method 1
the fluorinated polymer in the negative electrode film layer can form a fluoride-rich negative electrode solid electrolyte interphase film (SEI film), which is structurally stable and can enhance ionic conductivity
Implementation Method 2
the nitrile-based polymer material in the positive electrode film layer can, on one hand, enhance the ion transport performance of the positive electrode plate and, on the other hand, capture hydrogen ions to prevent their adverse effects on the positive electrode interface
Implementation Method 3
Through their synergistic effect, the battery containing the above electrode assembly can exhibit good cycle performance
Data Source
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AI summary
This application provides an electrode assembly, a battery cell, a battery, and an electric device. The electrode assembly includes a negative electrode plate, a positive electrode plate, and a separator, where the negative electrode plate includes a negative electrode film layer, the negative electrode film layer including a fluorinated polymer; and the positive electrode plate includes a positive electrode film layer, the positive electrode film layer including a nitrile-based polymer material. Using this electrode assembly can significantly improve the cycle performance of batteries.