Industry agrees on wireless charging standard for cars

January 25, 2017 // By Christoph Hammerschmidt
At a standards meeting at Audi AG in Ingolstadt, Germany, carmakers, Tier 1 suppliers, and technology providers from around the world have reached agreement on key technical and procedural elements of the upcoming SAE Recommended Practice “Wireless Power Transfer (WPT) and automated parking alignment and charging of electrified vehicles.” The goal of this standardization is to ensure interoperability and performance between electrified vehicles being developed by carmakers worldwide. Likewise, the standard will ensure that wireless charging stations streamline the charging of the next generation of electric vehicles. 

“Charging your vehicle should be as simple as parking it and walking away—and wireless charging with SAE J2954 enables that freedom and convenience to do this automatically”, says Jesse Schneider, chairman of the taskforce. Wireless charging is regarded across the automotive industry as a pivotal element to make electrified vehicles mainstream. Therefore, the agreement is “a major step forward for the industry”, as Schneider put it.

In detail, the taskforce members have agreed on specifications for the SAE J2954 Test Stations, which automakers will use as a basis to develop their wireless charging systems, and to verify interoperability of charging systems and vehicles regardless of manufacturer and model.  The taskforce agreed that the WPT1 (3.7 kW) circular coil system and the WPT2 (7.7 kW) circular coil system will be in the Test Stations used to test products developed by car makers, Tier 1 suppliers, and charging infrastructure suppliers to confirm SAE J2954 compatibility.  These wireless charging systems charge at the same rate as existing Level 1 and Level 2 wired chargers.

Earlier in 2016, SAE International performed bench testing of these systems at the US Department of Energy’s Idaho National Laboratory and TDK to confirm that charging rates, efficiency, and emissions meet regulatory guidelines and consumer expectations.  The testing results validated interoperability between different coils (both circular and DD). This enabled the RP SAE J2954 test station to have more freedom to prove interoperability with other topologies with newly established interoperability criteria. The goal is to standardize key elements but at the same time keep the door open for future innovation.