New 1800V photorelay powers safer and more efficient high-voltage EV batteries

Toshiba Electronics Europe GmbH has launched the TLX9165T, an automotive photorelay in a 10-pin SO16L-T package, that achieves an output withstand voltage of 1800V (min.). It is developed specifically to support the BMS for high-voltage, 800V EV batteries and battery ESS.

The wider adoption of EVs is particularly dependent on improvements in charging times and an extended cruising range. Both of these factors necessitate more efficient operation of battery systems. BMS are integral to accomplishing this efficiency by monitoring the battery charge status and the insulation between the battery and the vehicle body, which is crucial for the safe use of high-voltage batteries. In BMS that handle high voltages, electrically isolated photorelays are essential. Similarly, ESS, which are necessary for the efficient operation of renewable energy, adopt a comparable BMS configuration.

Photorelays typically used in these battery systems must withstand a voltage of approximately twice the system voltage; therefore, an output withstand voltage of over 1600V is needed for an 800V system. The company's new photorelay meets and exceeds this requirement. Furnished with a newly developed high-voltage MOSFET, it attains an output withstand voltage of 1800V (min.). This capability makes it highly suited to 800V systems.

The 10-pin SO16L-T package of the device includes a resin with a CTI of 600 or higher, belonging to Material Group I of the international standard IEC 60664-1. Also, its pin configuration ensures a creepage distance of 7.5mm or more on the light receiver side, which allows for an operating voltage of 1500V. The pin pitch and configuration are also identical to the company's existing SO16L-T packages (such as TLX9160T and TLX9152M), allowing the common use of PCB pattern designs.

The TLX9165T is a normally open (1-Form-A) device with an avalanche current rating of IAV=0.6mA and a high isolation voltage of 5000Vrms (min.). It is AEC-Q101 qualified and fully compliant with the IEC 60664-1 international standard. Key applications for the TLX9165T include automotive equipment, especially BMS for monitoring battery voltage, detecting mechanical relay sticking, and ground fault detection, and serving as a replacement for mechanical relays.