Thermoregulating Separators Based on Phase-Change Materials for Safe Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium-ion batteries (LIBs) are crucial for modern electronics and energy storage.
• Battery safety, particularly preventing thermal runaway, is a significant concern due to their widespread application.
• Current separators in LIBs primarily ensure ion transport and prevent short circuits but lack active thermal management.

Purpose of the Study:

• To design and evaluate a novel thermoregulating separator for enhanced lithium-ion battery safety.
• To investigate the performance of a phase-change material (PCM) integrated into a separator for thermal management.
• To demonstrate the effectiveness of the PCM-based separator in mitigating temperature rise during battery abuse conditions.

Main Methods:

• Development of a thermoregulating separator using paraffin wax encapsulated in hollow polyacrylonitrile nanofibers.
• Characterization of the phase-change material's enthalpy and thermal properties.
• Experimental simulation of internal short circuits using nail penetration tests on prototype pouch cells.

Main Results:

• The developed separator exhibits a wide enthalpy range (0-135.3 J g⁻¹), effectively absorbing heat.
• During nail penetration tests, the PCM-based separator significantly suppressed internal temperature rise compared to conventional separators.
• Battery cells with the PCM separator rapidly cooled down to room temperature within 35 seconds post-penetration.

Conclusions:

• The novel PCM-encapsulated nanofiber separator offers effective latent heat-storage capabilities.
• This design provides a promising strategy for overheat protection and significantly enhances the safety of lithium-ion batteries.
• The thermoregulating separator demonstrates potential for improving the reliability and safety of energy storage systems.