Automotive Photocouplers & Photorelays Toshiba Automotive Photocouplers and Photorelays are designed to maximize performance in the most rigorous of applications, vehicles. Toshiba's optical components are developed with the future in mind. Due to increased market demand for electric vehicles more devices are required to provide isolation across several voltage levels in areas such as Battery Management Systems (BMS), Inverters, and DC-DC Converters. Additionally, photorelays are a great solid state replacement for a traditional mechanical relay. One of the main benefits of using photorelays versus mechanical relays is reliability and longevity which is especially important in vehicles which have longer lifetimes.