Commercialization of SFM-50150 Screw-mounted Self Control Protector Compatible with High Rated Voltage of 125V and High Rated Current of 150A
- Improve the Safety of Li-ion Batteries, the Key device of Carbon Neutrality and the Shift to IoT -



Dexerials Corporation (Headquarters: Shimotsuke-shi, Tochigi; Representative Director and President: Yoshihisa Shinya; hereinafter, “Dexerials”), which provides leading-edge technologies, materials, and devices for smartphones, automobiles, and other products, announced today that it has developed and begun commercial production of SFM-50150, a Self Control Protector that is compatible with rated voltage of 125V and a rated current of 150A and that can be mounted with screws.


Dexerials’ Self Control Protector (hereinafter, SCP) is a fuse used as secondary protection, in which the fuse element melts to shut down the circuit when overcurrent and/or overcharging occur, due to malfunctioning of the primary protection that controls charging and discharging Li-ion battery packs. Since their launch in 1994, SCPs have been widely adopted for use in batteries of laptops, smartphones, power tools, and other equipment.

Recent years have seen an increase in the use of electric vehicles, including e-bikes, which are becoming increasingly popular as a means of achieving carbon neutrality, and electric automated guided vehicles (AGV) that are used in an ever wider range of applications as part of society’s shift toward IoT. Storage batteries and other energy storage systems (ESS) for supplying power to those vehicles are also proliferating, which has expanded the use of Li-ion batteries. Because these types of equipment handle higher voltage and current than consumer IT equipment, fuses for protecting them are in demand. In response, Dexerials has been developing an SCP which is compatible with high voltage and current.

The SFM-50150, for which Dexerials has now begun commercial production, is compatible with rated voltage of 125V and rated current of 150A, which are the highest in the lineup of SCPs from Dexerials.
Generally, the higher voltage a product uses, the more greatly it is affected by arc discharge caused by overcurrent in the Li-ion battery and the more difficult it is to shut down the circuit with a fuse element. The SFM-50150 employs an optimized structure to achieve the 150A rating and control arc discharge, which is an issue in the circuit shutdown of high-voltage. This has made it capable of shutting down high voltage and current.
It is also the first completely Pb-free screw-mounted SCP from Dexerials, which helps reduce the environmental impact.

Dexerials will continue its development efforts to make its SCPs compatible with even higher voltage and current and smaller in size, thereby improving the safety of Li-ion batteries in a wide range of applications. Thus, the company will drive carbon neutrality and support society’s digitalization and shift toward IoT, in its efforts to help build a sustainable society.

Details of Self Control Protector (SCP) SFM-50150

■ Product Name
  • Self Control Protector (SCP) SFM-50150
■ Features
  • Compatibility with rated voltage of 125V, the highest in the lineup from Dexerials, achieved with optimized materials and structure
    Materials used for the product’s case and its overall structure were optimized, which has resulted in successful control of arc discharge caused by overcurrent in the Li-ion battery. This has enabled rated voltage of 125V (an increase of 56% from conventional products*1), a level that was previously considered difficult to achieve.
  • Rated current of 150A achieved by optimizing the fuse element
    The fuse resistance was lowered by using a thicker fuse element than is seen with conventional products. This has made it possible to achieve the rated current of 150A, the highest ever in the lineup from Dexerials. The SFM-50150 is optimal for e-bikes, which need high current, and energy storage systems such as storage batteries.
  • Realize a completely Pb-free product
    The SFM-50150 utilizes a Pb-free*2 fuse element, developed in-house, and features optimized materials for the circuit board section. This has made it the first completely Pb-free screw-mounted SCP, thus helping reduce environmental impact.
■ Specifications
Product Name SFM-50150
Applicable cells in series 12 to 14 cells
Rated current (A) 150
Rated voltage (VDC)*3 125
Rated breaking capacity (A) 400
Operating voltage (V) 37.7 to 62.0
Heater resistance (Ω) 22.0 to 33.0
Fuse resistance (mΩ) 0.4
Dimension (mm) 40.0 x 29.4 x 18.0
  • *1120A SFM series
  • *2The European RoHS Directive that restricts usage of hazardous substances defines Pb-free as a Pb content of 1,000 ppm or less.
  • *3Maximum voltage at which cutoff of the fuse is possible. It is not the operating voltage for the heater.