Temperature-Responsive Battery Layer for Thermal Runaway Prevention
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Solution Overview
Problem
Rechargeable batteries face overheating and thermal runaway issues due to direct contact between positive and negative electrodes, especially when subjected to external thermal causes or manufacturing defects, leading to potential ignition or explosion.
Innovation Solution
Incorporating a shape variable layer that changes its resistance characteristics with temperature, separating the positive or negative electrode active material from the substrate, thereby regulating current flow and preventing overheating by blocking electron flow at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the separator shrinks at high temperature, then the positive and negative electrodes come into direct contact, but this causes thermal runaway and overheating
Solution Approach 1:
A shape variable layer is introduced as an intermediary component between the electrode active material and the current collector. This layer normally allows good electrical contact but transforms its shape at high temperature to create separation, acting as a temperature-dependent mediator that prevents direct electrode contact when the separator fails
Solution Approach 2:
The shape variable layer undergoes a temperature-induced parameter change in its physical shape. At normal operating temperatures, the layer maintains a flat configuration ensuring good electrical contact. When temperature exceeds a threshold, the layer transforms to a curved or buckled shape, increasing the distance between positive and negative electrodes and preventing thermal runaway
2Use of energy by moving object
If current flows through contact resistance portions, then heat is generated, but this localized heating can lead to ignition
Solution Approach 1:
The shape variable layer serves as a temperature-responsive intermediary that monitors and responds to localized heating conditions. When excessive heat is generated at contact resistance portions, the layer detects the temperature rise and transforms its shape to increase electrode separation, thereby interrupting the harmful current flow before ignition can occur
3Reliability
If metal foreign matter is incorporated, then insulation between electrodes is compromised, but this causes internal short circuit and localized heating
Solution Approach 1:
The shape variable layer provides self-service safety protection by automatically responding to the presence of metal foreign matter. When conductive contaminants cause localized heating or partial short circuits, the temperature-sensitive layer autonomously transforms its shape to increase electrode separation, eliminating the need for external detection or intervention systems
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
Effectively prevents thermal runaway and ignition by ensuring that the shape variable layer transitions to a high resistance state at elevated temperatures, thereby protecting the battery from overheating and maintaining safe operation.
Implementation Method 1
When a temperature of the rechargeable battery increases to be greater than or equal to a threshold... the shape variable layer, which has been in contact with the positive electrode active material layer or the negative electrode active material layer, changes in shape
Implementation Method 2
The shape variable layer is configured to regulate current between the positive or negative electrode substrate layer and the positive or negative electrode active material layer at a temperature greater than or equal to a pre-determined temperature
Data Source
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Figure 3
Figure 4AA
AI summary
A rechargeable battery is provided. The rechargeable battery includes a positive electrode substrate layer; a positive electrode active material layer disposed adjacent to the positive electrode substrate layer; a negative electrode substrate layer; a negative electrode active material layer disposed adjacent to the negative electrode substrate layer; a separator disposed between the positive electrode active material layer and the negative electrode active material layer; and a shape variable layer disposed between the positive electrode substrate and the positive electrode active material layer or between the negative electrode substrate and the negative electrode active material layer.