Multi-Layer Battery Electrode Binders for High-Temperature Storage
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Solution Overview
Problem
Lithium ion battery electrodes experience capacity degradation and increased resistance when stored at high temperatures due to binder swelling, which affects adhesiveness and electron conductivity.
Innovation Solution
A multi-layered electrode structure is implemented, with a first layer containing a binder that swells less than 25% in a liquid electrolyte and a second layer with a binder that swells more than 25%, both including active and conductive materials, to reduce battery resistance and improve high-temperature storage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a binder with high swelling ratio is used to improve electron conductivity, then battery resistance increases, but adhesiveness degradation occurs during high-temperature storage
Solution Approach 1:
The electrode layer is divided into multiple layers, each containing binders with different swelling characteristics. The first layer contains a binder with low swelling ratio to maintain adhesiveness, while the second layer contains a binder with high swelling ratio to improve electron conductivity. This segmentation allows simultaneous optimization of both adhesiveness and conductivity without compromise.
Solution Approach 2:
Different regions of the electrode layer are assigned different binder properties tailored to local functional requirements. The first layer near the current collector uses low-swelling binder for strong adhesion, while the second layer uses high-swelling binder for enhanced conductivity. This local quality differentiation resolves the contradiction by optimizing each region for its specific function.
2Object-affected harmful factors
If binder swelling is increased to reduce battery resistance, then electron conductivity improves, but capacity degradation occurs during high-temperature storage
Solution Approach 1:
The electrode is segmented into layers with different binder swelling characteristics. The first layer's low-swelling binder prevents capacity degradation during storage, while the second layer's high-swelling binder reduces battery resistance. This segmentation enables both capacity durability and low resistance to be achieved simultaneously.
Solution Approach 2:
The electrode layer employs a composite structure with multiple binder types having complementary properties. The combination of low-swelling and high-swelling binders in different layers creates a composite material system that simultaneously provides storage stability and low resistance, overcoming the limitations of single-binder systems.
3Ease of manufacture
If a single-layer electrode structure is used to simplify manufacturing, then production complexity decreases, but both adhesiveness and conductivity cannot be optimized simultaneously
Solution Approach 1:
The electrode layer is segmented into multiple layers, each optimized for specific functions. This segmentation enables simultaneous optimization of adhesiveness and conductivity, achieving better performance balance despite increased manufacturing steps. The segmented structure is applied consistently across large areas through standardized processes.
Solution Approach 2:
Different layers are assigned different binder compositions tailored to local functional needs. This local quality optimization achieves superior overall performance by ensuring each region contributes its specialized function, with the multi-layer structure being manufactured using scalable techniques.
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 electrode structure effectively inhibits adhesiveness degradation and electron conductivity loss, maintaining capacity durability and reducing battery resistance while enhancing resistance to high-temperature storage.
Implementation Method 1
a degree of swelling of the first binder to a liquid electrolyte is lower than a degree of swelling of the second binder to the liquid electrolyte
Data Source
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AI summary
A main object of the present disclosure is to provide an electrode capable of reducing the resistance of a battery and also capable of improving resistance to high temperature storage. The present disclosure achieves the object by providing an electrode to be used for a battery, the electrode including a current collector and an electrode layer, wherein the electrode layer includes layers in the order of a first layer and a second layer; the first layer contains a first binder, the second layer contains a second binder, and a degree of swelling of the first binder is lower than a degree of swelling of the second binder.