Market Overview:
This polymer electrolyte for lithium-ion batteries can be used to inhibit thermal hazards associated with large-format and high-power lithium-ion batteries. Batteries and energy storage is an expanding market that is worth tens of billions of dollars annually, with the market for Lithium-Ion batteries expected to hit $30 billion by 2020. Due to this market growth, many research efforts aim to either make lithium-ion batteries larger or designing cells that discharge at faster rates to increase power output. Both these endeavors, however, lead to increased thermal hazards such as fires or explosions. Clemson researchers have developed a polymer electrolyte for lithium-ion batteries with temperature responsive properties that can be used to inhibit thermal hazards associated with large-format and high-power lithium-ion batteries. This is achieved by a phase transition that is based on the separation of a polymer from the electrolyte solution. The phase separation results in a decrease in conductivity, preventing battery operation and avoiding destructive safety measures. When the battery cools down, the polymer re-mixes into the solution and the battery regains function. This reversibility allows for prolonged battery life and avoids wasted devices, saving costs for purchases of new batteries and equipment.
Application Stage of Development
Large format Li-ion batteries, vehicle applications; energy storage Validated Prototype
Advantages
• Incorporates intrinsic safety mechanism that prevents the battery from overcharging or discharging,
reducing the thermal hazards associated with lithium ion batteries
• Can be processed in current manufacturing settings, resulting in no additional need for new equipment
• Capable of responding to local hotspots within the battery cell itself
Technical Summary
The electrolyte is comprised of a polymer and lithium salt dissolved in an ionic liquid mixture. At relatively low temperatures, the battery operates with good electrochemical properties. As the temperature increases beyond a specific value, the polymer phase separates from the ionic liquid – resulting in a solution that has low ionic conductivity. The decrease in battery performance is caused by the low conductivity of the phase separated suspension and the polymer aggregates adsorbing to the battery electrode surface. When the battery cools down, the polymer re-mixes into solution and the battery regains function. This approach provides an intrinsic safety mechanism that prevents the battery from overcharging or discharging when local temperatures get too high.
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Inventors: Mark Roberts, Jesse Kelly
Application Type: Utility
Serial Number: 14/926,213
CURF Reference: 2014-073