UL 2597 Surface Tracking Test (STT) for Transportation Applications 

The automotive market and EVs

Manufacturers and suppliers are continuously working to meet the ever-increasing demand for lighter batteries with higher voltages, longer lifespans and shorter charging times. UL Solutions has designed a new tracking test to support innovation in this area and advance industry standards for the selection of insulating materials.

Today, most EVs are built with 400-volt (V) architecture. However, more and more manufacturers are redesigning their vehicles and moving toward 800 V or higher architectures for faster charging times and better efficiency.

As the automotive industry works to supply consumers with faster charging, improved connector performance and higher-capacity batteries, it became clear that a new generation of methodology was needed to evaluate the materials used in EV systems with higher volt ranges. This prompted our experts to develop the Surface Tracking Test (STT) method.

What is STT?

The STT method was designed specifically for evaluating the material performance of EV architectures operating between 600 V and 900 V. It also provides additional guidance and insight into the material selection process for automotive manufacturers.

This is the first standardized test method of its kind in this voltage range on the market and published in UL 2597, the Outline of Investigation for Test Method for Materials for Use in Transportation Applications: Surface Tracking Test (STT) Method.

Why UL Solutions?

By progressively advancing our testing methods and technologies, we can better predict and evaluate material behavior under different conditions to enhance the reliability, quality and safety of EV architectures. As the EV industry evolves, more voltage testing options will be needed. Our experts and methods are indispensable resources that can help you prepare for stringent regulatory frameworks, meet stakeholder expectations and fill gaps for more rapid advancement.