PTC-Coated Battery Electrode Tabs for Thermal Runaway Blocking
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Solution Overview
Problem
Secondary batteries face safety issues due to thermal runaway caused by internal short circuits, which can lead to ignition or explosion, especially as their capacity and energy density increase.
Innovation Solution
An electrode with a conductive coating layer made from a conducting polymer whose resistance increases with temperature, applied to both the main body and electrode tab of the current collector, to prevent thermal runaway by blocking electric current when the battery temperature rises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacity and energy density of secondary batteries are increased, then the energy storage capability is improved, but the risk of thermal runaway and safety accidents increases
Solution Approach 1:
A conductive coating layer is introduced as an intermediary between the electrode mixture layer and the current collector. This coating layer includes a conducting polymer that acts as a mediator to block electron movement at the electrode tab when temperature rises, preventing thermal runaway while maintaining the high energy density of the battery
Solution Approach 2:
The conducting polymer in the conductive coating layer undergoes parameter changes in its electrical conductivity based on temperature. At normal operating temperatures, the polymer maintains good conductivity for electron transport. When temperature rises due to short circuit or overheating, the polymer's resistance increases dramatically, blocking electron flow and preventing thermal runaway
2Reliability
If a conductive coating layer including a conducting polymer is formed on the current collector, then thermal runaway is suppressed when temperature rises, but the manufacturing complexity increases
Solution Approach 1:
The conductive coating layer is applied selectively to specific regions of the current collector, particularly focusing on the electrode tab area where short circuits are most likely to occur. This localized approach provides safety benefits where most needed while minimizing the addition of complex structures across the entire electrode
Solution Approach 2:
The electrode structure is enhanced by incorporating a composite conductive coating layer made of conducting polymer on the current collector. This composite structure combines the electrical conductivity of the polymer with the mechanical strength of the current collector, providing both safety and structural integrity without excessive complexity
3Reliability
If a conductive coating layer is formed on the current collector, then an additional manufacturing process is required, but the safety is improved
Solution Approach 1:
The conductive coating layer is formed on the current collector during the electrode manufacturing process, before the electrode assembly is completed and before the battery is assembled. This preliminary action ensures that the safety feature is already in place during normal manufacturing operations, and the coating can be applied using standard coating equipment and processes
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 solution effectively minimizes the risk of thermal runaway and improves battery safety by blocking electric connections between electrode tabs during internal short circuits, allowing for safer operation even at elevated temperatures.
Implementation Method 1
a conductive coating layer which is formed on at least one surface of the current collector and includes a conducting polymer of which resistance increases when a temperature rises
Data Source
AI summary
A an electrode having an improved safety,including: a current collector including a main body and an electrode tab formed at one side of the main body; a conductive coating layer which is formed on at least one surface of the current collector and includes a conducting polymer of which resistance increases when a temperature rises; and an electrode mixture layer which is formed on the conductive coating layer. Herein, the conductive coating layer is formed on a region including both the main body and the electrode tab.