Thermally Responsive Composite Electrolyte for Battery Shutdown
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Solution Overview
Problem
Lithium ion batteries face safety risks due to flammable components that can lead to thermal runaway and catastrophic failures, even with the use of solid-state electrolytes, which can still conduct ions and generate heat upon short circuiting.
Innovation Solution
A solid-state electrolyte composition with a thermally responsive composite that includes ionically conductive inorganic particles and polymers with a positive coefficient of thermal expansion, which significantly reduces ionic conductivity above a cutoff temperature (Tc) between 60° C. and 180° C., thereby inhibiting thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If solid-state electrolyte is used to replace flammable liquid electrolyte, then flammability is reduced, but ionic conductivity increases with temperature leading to potential thermal runaway
Solution Approach 1:
The patent applies parameter changes by utilizing the temperature-dependent ionic conductivity characteristic of solid electrolytes. The system is designed to operate normally at low temperatures where ionic conductivity is high, but automatically shuts down at elevated temperatures where ionic conductivity increases excessively, preventing thermal runaway. This transforms the potentially harmful temperature-conductivity relationship into a safety mechanism.
Solution Approach 2:
The patent converts the harmful effect of increased ionic conductivity at high temperatures into a beneficial safety feature. Instead of trying to prevent the conductivity increase, the system harnesses it to automatically stop ion transport when temperature exceeds safe operating limits, thereby preventing catastrophic thermal runaway while maintaining excellent safety performance.
2Productivity
If ionic conductivity is maintained at high temperatures, then battery performance is preserved, but thermal runaway risk increases
Solution Approach 1:
The patent applies dynamics by creating a temperature-responsive system where ionic conductivity dynamically adjusts based on operating conditions. At normal operating temperatures, the solid electrolyte maintains high ionic conductivity for optimal battery performance. When temperature rises above a threshold, the increased ionic conductivity automatically triggers shutdown, dynamically switching from performance mode to safety mode.
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 thermally responsive electrolyte composition provides a built-in safety mechanism by substantially reducing ion flow and heat generation at high temperatures, enhancing the safety and reliability of lithium ion batteries.
Implementation Method 1
one or more polymers that have a positive coefficient of thermal expansion
Implementation Method 2
a plurality of inorganic particles that are ionically conductive between the anode and the cathode
Data Source
AI summary
Provided herein are compositions of solid-state ionically conductive composite materials that include particles of an inorganic phase in a matrix of an organic phase having a positive thermal coefficient of expansion. When the temperature of the composition is below a cutoff temperature Tc, the composition is ionically conductive and may be used as an electrolyte. As the temperature increases above Tc, the organic phase expands and reduces the ionic conductivity of the composition.