PP Compound First to Receive UL Certification for Thermal Runaway Protection of EV Batteries

Sabic’s Stamax 30YH570 resin for use in electric vehicle (EV) battery systems has earned the UL Verified Mark from Underwriters Laboratories. The compound is reportedly the first-ever polymer to pass the thermal runaway box test, according to UL 2596, Test Method for Thermal and Mechanical Performance of Battery Enclosure Materials.

This 30% glass fiber–reinforced polypropylene (PP) copolymer resin, offered under Sabic’s Bluehero electrification initiative, is the first EV-grade polymer to receive UL verification for marketing claims of thermal and mechanical performance. UL verification, based on an objective, scientific assessment by a respected third party, can give customers high confidence in the flame delay performance of this product, said Sabic.

The vast majority of EV batteries perform without issues throughout their useful life. Although thermal runaway incidents are rare, the safety-conscious automotive industry is highly focused on ensuring that the design and performance of EV battery systems prolong the time available to exit a vehicle by delaying propagation of a fire beyond the battery pack. A key consideration is the proper selection and deployment of fire-protection materials used for battery pack components, including enclosures and covers, trays, and thermal barriers that separate cells into groups.

According to Venkatakrishnan Umamaheswaran, Sabic’s global automotive marketing director: “UL verification for the thermal runaway protection of Stamax 30YH570 resin is a significant milestone in our development of polymer materials for today’s rapidly evolving EV battery systems. This recognition not only underscores the exceptional performance and safety features of our polymer, but also reinforces the importance of our Bluehero initiative. By providing cost-effective, lightweight plastic solutions, Sabic is helping to advance EV technology.”

Thermal runaway box testing according to UL 2596, Test Method for Thermal and Mechanical Performance of Battery Enclosure Materials, demonstrated that Stamax 30YH570 resin withstood an internal box pressure of 250 kPa and an internal box temperature of 420°C. Results were based on three replicate tests, with a panel thickness of 4 mm. The Sabic material features an intumescent capability that helps with fire suppression. Other key properties include high stiffness and strength and easy processing.