Volume-Expandable Additive for Thermal Runaway Prevention
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Solution Overview
Problem
Conventional lithium secondary batteries face safety concerns due to high energy density, which can lead to ignition and explosion risks from temperature increases, and existing safety measures either require additional assembly space or compromise battery performance.
Innovation Solution
An additive comprising an inner core of volume-expandable material fused at a certain temperature, combined with an outer coating layer of high conductivity material, which rapidly increases internal resistance to prevent ignition and explosion without degrading battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high energy density is increased to improve battery performance, then battery capacity and voltage are improved, but ignition and explosion risks increase due to temperature rise
Solution Approach 1:
The invention changes the electrical resistance parameter of the battery by incorporating a temperature-dependent resistive material. This material's resistance increases with temperature, automatically adjusting the electrical parameters to prevent thermal runaway while maintaining high energy density operation
Solution Approach 2:
A resistive material acts as an intermediary component between the high-energy battery materials and the thermal environment. This intermediary material absorbs excess thermal energy through resistance increase, preventing direct thermal runaway of the battery while allowing high energy density operation
2Reliability
If conventional safety measures (such as cooling systems or protective circuits) are added to prevent ignition, then safety is improved, but device complexity and assembly space requirements increase
Solution Approach 1:
The resistive material provides self-regulating safety functionality without requiring external control systems. As temperature increases, the material's resistance automatically increases, creating a self-regulating mechanism that prevents thermal runaway without needing complex monitoring or control circuits
Solution Approach 2:
The safety function is merged with the existing battery structure by incorporating the temperature-dependent resistive material directly into the battery components (electrode, separator, or electrolyte). This integration eliminates the need for separate safety systems while maintaining safety functionality
3Reliability
If conventional safety measures (such as cooling systems or protective circuits) are added to prevent ignition, then safety is improved, but manufacturing cost increases
Solution Approach 1:
The resistive material serves as a low-cost, consumable safety component that can be easily incorporated during battery manufacturing. Rather than requiring expensive, complex safety systems, this approach uses inexpensive temperature-dependent resistive materials that provide effective safety functionality
Solution Approach 2:
By merging the safety function with existing battery components through the resistive material, the invention eliminates the need for separate safety system manufacturing processes. This integration reduces manufacturing steps and costs while achieving the same safety objectives
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 additive effectively prevents ignition and explosion by rapidly increasing internal resistance at abnormal temperatures, ensuring safety without compromising the electrochemical device's performance at normal conditions.
Implementation Method 1
the inner core is formed using a volume-expandable material fused at a certain temperature or more
Implementation Method 2
the inner core is formed using a volume-expandable material fused at a certain temperature or more
Implementation Method 3
the outer coating layer is formed using a conductive material with higher conductivity than that of the inner core
Implementation Method 4
Increase in temperature of a battery promotes reaction between an electrolyte and an electrode. Then, heat of reaction is radiated, and the temperature of the battery is further increased
Data Source
Figure 1~2
Figure 3
AI summary
Disclosed herein is an additive for improvement in safety of an electrochemical device, including an inner core and an outer coating layer, wherein the inner core is formed using a volume-expandable material fused at more than a predetermined temperature while the outer coating layer is formed using a conductive material with higher conductivity than that of the inner core and covers an outer face of the inner core. The disclosed additive rapidly increases resistance of the electrochemical device before ignition/explosion of the device caused by temperature rise, thereby effectively preventing ignition/explosion of the electrochemical device without deterioration in performance of the electrochemical device.