The key to long-range EVs: Opto-SiC MOSFET Relays applied on BMS | B.T - A manufacturer of Solid State Relays, Reed Relays and MEMS Switches.

Battery Management System is a crucial technology managing entire battery packs placed in electric vehicles. These battery packs are composed of many battery cells. The oversight that a BMS provides includes Insulation Monitor and Detection, reporting operational status, and continually optimizing battery performance by balancing each cell's remaining power. Opto-MOSFET Relays (a.k.a Solid State Relays) can be applied to all three functions. This article will go through Bright Toward's newly introduced Opto SiC MOSFET Relays and their role in BMS's Insulation Detection. B.T The key to long-range EVs: Opto-SiC MOSFET Relays applied on BMS Introduction. Bright Toward Industrial Co., Ltd is a manufacturer of Solid State Relays, Reed Relays and MEMS Switches.. Manufacturer of Opto-MOSFET Solid State Relays, Reed Relays, and RF MEMS Switches. We mainly serve the Semiconductor Testing, ATE, BMS (Battery Management Systems), industrial machinery and Electric Vehicle industries.

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The key to long-range EVs: Opto-SiC MOSFET Relays applied on BMS

Bright Toward has been supplying major automotive battery manufacturers worldwide; we saw the demand for higher load voltage solid state relays increasing. A Silicon-based Opto-MOSFET Relay's physical limit is around 1500V; therefore, we initiated the development of Silicon Carbide based Opto-MOSFET Relays in 2016 to improve load voltage further.

Bright Toward has been supplying major automotive battery manufacturers worldwide; we saw the demand for higher load voltage solid state relays increasing. A Silicon-based Opto-MOSFET Relay's physical limit is around 1500V; therefore, we initiated the development of Silicon Carbide based Opto-MOSFET Relays in 2016 to improve load voltage further.

The key to long-range EVs: Opto-SiC MOSFET Relays applied on BMS

Battery Management System is a crucial technology managing entire battery packs placed in electric vehicles. These battery packs are composed of many battery cells. The oversight that a BMS provides includes Insulation Monitor and Detection, reporting operational status, and continually optimizing battery performance by balancing each cell's remaining power. Opto-MOSFET Relays (a.k.a Solid State Relays) can be applied to all three functions. This article will go through Bright Toward's newly introduced Opto SiC MOSFET Relays and their role in BMS's Insulation Detection.

Writer: Ryan Hsu / Ligo Chen

What is BMS (Battery Management System)?

Circuit Diagram for Insulation Detection in BMS

If the insulation in any battery cell deteriorates, a ground-fault current passes through our relay, outputting an alarm signal.

Circuit Diagram for Insulation Detection in BMS

What is Insulation Monitor/Detection?

The insulation Monitor/Detection function in BMS ensures the battery insulation is healthy and no leakage occurs. It works like this: If the insulation in any battery cell deteriorates, a ground-fault current passes through our relay, outputting an alarm signal. The relay has to withstand a voltage higher than the nominal voltage of the battery pack, usually with a buffer. For example, a battery pack with 800V nominal voltage usually requires a relay with a load voltage greater than 1600V.

Why is there an increasing need for higher load voltage Solid State Relays in BMS?

Early electric cars suffered from low ranges and slow charging times. To increase the EV's range and improve charging speed, battery manufacturers need to increase the total voltage and current rating. Therefore, relays rated at higher voltages must ensure the insulation monitoring function works properly. Bright Toward has been supplying major automotive battery manufacturers worldwide; we saw the demand for higher load voltage solid state relays increasing. A Silicon-based Opto-MOSFET Relay's physical limit is around 1500V; therefore, we initiated the development of Silicon Carbide based Opto-MOSFET Relays in 2016 to improve load voltage further. We successfully announced the product line in 2018. Major automotive companies validated our SiC Opto-MOSFET Relays in the following few years. As of 2022, Opto-SiC MOSFET Relays' monthly production has exceeded 4,000,000 pieces. 

So far, major automotive companies have validated our 1800V Opto-SiC MOSFET Relays (AA58, AS58) with mass production ongoing. Our 3300V Opto-SiC MOSFET Relays (AA53, AS53) are also production ready, with validation ongoing. Our 6600V Opto-SiC MOSFET Relays are in the process of qualification with engineering samples ready. Bright Toward is prepared for the future and would love to be a part of your design.

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B.T - A manufacturer of Solid State Relays, Reed Relays and MEMS Switches.

Located in Taiwan since 1988, Bright Toward Industrial Co., LTD. is a relay supplier and manufacturer. Main products, including Opto-MOSFET Relays, Opto-SiC MOSFET Relays, Solid State Relays, Reed Relays, And RF MEMS Switches, etc.

B.T supplies relays to the world's semiconductor and automotive industries for over three decades and has long term long-term partnerships with OKITA Works based in Japan; Menlo Microsystems based in California; JEL Systems based in Japan and Teledyne Relays and Coax Switches based in California. Mainly serve the Semiconductor Testing, ATE, BMS (Battery Management Systems), industrial machinery and Electric Vehicle industries.

B.T has been offering customers high-quality Opto-MOSFET and Opto-SiC MOSFET relays since 1988, both with advanced technology and 30 years of experience, B.T ensures each customer's demands are met.