Polymer separators based on polyolefins, like polyethylene and polypropylene, are widely used in commercial batteries. Application of Li-ion batteries as energy storage systems in HEVs and full EVs necessitates improvements to the separators currently being used to significantly increase safety.
Battery Separator Puncture Testing
Polyolefin producers are seeing increasing requirements for improved energy density and cycle life of the batteries. Issues with the selection of the cell separator materials can compromise battery integrity and increase the potential for internal short circuits, leading to thermal runaway, fire and even explosions. Puncture resistance to an impact event is a crucial mechanical property used to assess and select the material with the best performance, while reducing the thickness, number of layers and weight.
Conducting tests with Instron’s 9450 impact droptower per ASTM D3763, ISO 6603 or UL2591, provides information not only on the resistance to penetration but also the maximum load and deformation the material can withstand. Bluehill® Impact software, with smart defaults and intuitive workflow, fully controls the acquisition chain made up of Instron-proprietary accredited force sensors and strain gauge or piezoelectric load cards for real-time display of force/deformation curves and material properties. Additionally, the software can manage the thermostatic chamber for testing cell separator materials at sub-ambient conditions to simulate real life applications. If throughput and resources optimization is a concern, Instron offers smart solutions to test up to 30 specimens fully unmanned or up to 10 specimens with limited operator interface, and that can provide as much as 50% savings in terms of cycle time and liquid nitrogen consumption.