Conductive Polymer Electrode Layer for Short-Circuit Resistance
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Solution Overview
Problem
Electrochemical devices, such as batteries, are prone to ignition or explosion due to short circuits caused by overcharge, high temperatures, or external impacts, leading to thermal runaway and increased risk of volume expansion and ignition.
Innovation Solution
An electrode for electrochemical devices is designed with a conductive polymer layer between the electrode current collector and the active material layer, enhancing adhesive strength and interface resistance to prevent direct contact between collectors during short circuits, thereby acting as a resistance layer and ensuring safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive polymer layer is added between the current collector and active material layer, then short circuit resistance is improved and safety is enhanced, but device complexity and manufacturing complexity increase
Solution Approach 1:
A conductive polymer layer is introduced as an intermediary between the current collector and active material layer. This intermediate layer serves as a resistance barrier that prevents direct contact during short circuit conditions, while maintaining electrical conductivity during normal operation. The polymer layer acts as a mediator that resolves the contradiction by providing safety functionality without completely blocking the conductive path.
Solution Approach 2:
The electrode structure employs composite materials by combining the current collector, conductive polymer layer, and active material layer into an integrated multi-layer system. The conductive polymer layer is composed of specific polymers (polyaniline, polypyrrole, or polythiophene) that provide both conductivity and resistance properties, creating a composite structure that achieves enhanced safety while maintaining electrical functionality.
2Reliability
If a conductive polymer layer is added to prevent direct contact between collectors, then safety is improved, but manufacturing precision and production complexity increase
Solution Approach 1:
The patent specifies particular parameter ranges for the conductive polymer layer to optimize both safety and manufacturability. The thickness is controlled within 0.1-10 μm, the polymer content is limited to 1-50 wt% of the active material, and specific polymer types are selected. These parameter specifications make the manufacturing process controllable and reproducible, reducing the precision burden while ensuring safety performance.
3Reliability
If the conductive polymer layer thickness is increased to enhance resistance, then short circuit prevention is improved, but interface resistance during normal operation increases and performance deteriorates
Solution Approach 1:
The thickness of the conductive polymer layer is precisely controlled within the range of 0.1-10 μm. This optimized thickness parameter provides sufficient resistance during short circuit conditions while maintaining adequate electrical conductivity during normal operation. The parameter optimization resolves the contradiction by finding the optimal balance point where the layer is thick enough to provide safety but thin enough to maintain performance.
Solution Approach 2:
The conductive polymer layer exhibits different functional properties at different scales: at the micro-scale (0.1-10 μm thickness), it provides sufficient resistance for safety, while at the macro-scale of the entire electrode structure, it maintains adequate conductivity for normal operation. The local quality of the polymer layer is optimized to provide context-dependent functionality.
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 conductive polymer layer effectively increases short circuit resistance, preventing rapid current flow and ensuring safety by maintaining performance without interfering with the conductive path during normal operation, thus reducing the risk of ignition and improving battery lifespan.
Implementation Method 1
the conductive polymer layer effectively increases short circuit resistance, preventing rapid current flow
Implementation Method 2
enhancing adhesive strength and interface resistance to prevent direct contact between collectors during short circuits
Data Source
AI summary
The present disclosure provides an electrode for an electrochemical device comprising an electrode current collector, a conductive polymer layer that is located on at least one surface of the electrode current collector; and an electrode active material layer that is located on an upper surface of the conductive polymer layer and includes an electrode active material and a binder polymer, wherein the conductive polymer layer includes a poly(thiophene)-based polymer represented by Chemical Formula 1:wherein R1 to R4, m and n are describe herein.