Layered Battery Electrode Structure for Low Interfacial Resistance
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Solution Overview
Problem
The existing manufacturing method of electrodes for batteries, particularly those using the dry method with polytetrafluoroethylene (PTFE) as a binder, results in high interfacial resistance and poor electron conductivity at the interface between the electrode layer and the current collector.
Innovation Solution
A manufacturing method that involves forming a first electrode layer on a current collector using electrostatic film formation, wet film formation, or rolled film formation, and a second electrode layer using rolled film formation. The first electrode layer includes active material particles coated with a resin different from PTFE, while the second electrode layer contains active material particles and fibrous PTFE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polytetrafluoroethylene (PTFE) is used as a binder in the dry method, then the electrode can be manufactured without solvent, but the interfacial resistance at the interface between electrode layer and current collector becomes high and electron conductivity deteriorates
Solution Approach 1:
The electrode layer is divided into multiple layers with different functions. The first layer (near current collector) uses resin different from PTFE to ensure good adhesion and electron conductivity at the interface. The second layer (outer layer) uses PTFE to provide the desired binder properties. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
Different regions of the electrode layer are assigned different material compositions. The region adjacent to the current collector uses resin different from PTFE to achieve low interfacial resistance and high electron conductivity. The outer region uses PTFE to maintain the overall binder functionality. This local differentiation resolves the contradiction by optimizing material properties at each specific location.
2Device complexity
If PTFE is used as binder in rolled film formation, then the electrode structure is simplified, but the adhesion at the interface between electrode layer and current collector deteriorates
Solution Approach 1:
The electrode layer is segmented into multiple layers with different material compositions. The first layer uses resin different from PTFE to ensure strong adhesion to the current collector. The second layer uses PTFE to maintain the desired binder properties. This segmentation allows the structure to remain relatively simple while achieving both good adhesion and proper binder functionality.
Solution Approach 2:
The adhesion property is optimized locally at the interface region by using resin different from PTFE in the first layer. The bulk of the electrode layer maintains PTFE for binder functionality. This local quality differentiation resolves the contradiction between structural simplicity and adhesion strength.
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 method significantly reduces the interfacial resistance and enhances electron conductivity between the electrode and the current collector, leading to improved battery performance.
Implementation Method 1
The first electrode layer is fabricated by electrostatic film formation, wet film formation, or rolled film formation.
Implementation Method 2
the rolled film formation includes fibrillation of polytetrafluoroethylene in a mixture containing active material particles and polytetrafluoroethylene
Data Source
AI summary
A method of fabricating an electrode includes: fabricating a first electrode layer disposed on a current collector; and fabricating a second electrode layer disposed on the first electrode layer. The first electrode layer is formed by electrostatic deposition, wet deposition, or rolled film formation. The second electrode layer is formed by rolled film formation. When the first electrode layer is fabricated by rolled film formation, at least part of a surface of active material particles used in the rolled film formation is coated with a resin that is different from polytetrafluoroethylene.