PTC Polymer-Layer Electrode for Battery Thermal Runaway Blocking
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Solution Overview
Problem
Secondary batteries are prone to ignition or explosion due to short circuits caused by direct contact between positive and negative electrodes, especially under abnormal conditions such as overcharging, high temperatures, or external shocks, leading to increased risk of heat generation and volume expansion.
Innovation Solution
An electrode with a polymer layer that exhibits a Positive Temperature Coefficient (PTC) effect, controlling charge movement based on temperature to maintain low resistance in normal conditions and high resistance in abnormal conditions, thereby stabilizing the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer layer with PTC effect is applied to control resistance at high temperatures, then safety under abnormal conditions is improved, but device complexity increases
Solution Approach 1:
The polymer layer is integrated within the existing electrode structure, nested between the current collector and the electrode active material layer, rather than adding a separate external component. This nesting approach incorporates the PTC protection function directly into the electrode itself, maintaining safety while minimizing additional structural complexity
Solution Approach 2:
The polymer layer's resistance parameter dynamically changes with temperature through the PTC effect. At normal operating temperatures, the polymer maintains low resistance to allow efficient charge transfer. When abnormal temperature rise occurs, the polymer's resistance sharply increases, automatically blocking current flow and preventing thermal runaway, thus improving safety without requiring external control systems
2Stability of the object's composition
If polymer layer is added to exhibit PTC effect, then stability under high temperature is improved, but manufacturing complexity increases
Solution Approach 1:
The polymer layer is applied locally only where needed - specifically between the current collector and the electrode active material layer - rather than requiring treatment of the entire battery assembly. This localized application maintains manufacturing efficiency while providing targeted thermal stability protection at the critical interface
Solution Approach 2:
The electrode is designed as a composite structure integrating the polymer layer with the current collector and electrode active material layer. This composite approach combines the electrical conductivity of the traditional electrode materials with the temperature-responsive properties of the polymer, achieving enhanced thermal stability through material composition rather than complex manufacturing processes
3Reliability
If polymer layer with suitable oxidation potential is used, then electrochemical stability is improved, but device complexity increases
Solution Approach 1:
The polymer layer serves multiple functions simultaneously: it provides PTC effect for thermal protection, maintains appropriate oxidation potential for electrochemical stability, and acts as an integral part of the electrode structure. This multi-functionality achieves electrochemical stability without requiring separate components for each function, thereby avoiding increased device 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 polymer layer ensures stable battery operation in normal conditions while preventing energization and ensuring safety in abnormal conditions by rapidly increasing resistance to prevent ignition or explosion.
Implementation Method 1
a polymer layer, between the current collector and the electrode active material layer, the polymer layer exhibits a so-called PTC (Positive Temperature Coefficient) effect
Data Source
Figure 1~2
AI summary
The present specification discloses an electrode and a use thereof. The electrode comprises a polymer layer exhibiting a so-called PTC (Positive Temperature Coefficient) effect at a required level at a required time, whereby it can be suitably applied in applications where stability problems due to abnormally high heat or flame are caused. The polymer layer can exhibit oxidation potential characteristics suitable for an electrode use, where such oxidation potential characteristics can be stably maintained even under harsh environments. In the polymer layer of the electrode, the PTC effect can rapidly appear at a required time. The present specification also discloses a use of the electrode.