New Industry Products

Eaton’s Self-Control Fuse Makes Safety a Reality for Battery Design

July 01, 2023 by Jake Hertz

The self-control fuse products make safety a primary factor in power system design. This article will examine Eaton’s technology and its role in the marketplace.

A major consideration in the design of any power system is safety. In the realm of battery-powered devices, safety is a challenge as designers balance the tradeoffs of safety and area constraints, which is a standard restriction in battery-powered devices.

Safety is key in battery-powered devices

Safety is key in battery-powered devices. Image used courtesy of Pexels

One such solution that aims to balance this tradeoff is Eaton Bussman’s self-control fuse (SCF) products, designed to offer high levels of safety in small, space-constrained battery devices. 


What is the Self-Control Fuse?

For ensuring the safe operation of battery-powered devices, Eaton offers their flagship self-control fuse products.

The SCF family is a series of surface-mounted devices that feature an integrated fuse element assembly and heater element. The product is intended to be controlled by external circuitry such as an IC or a FET, which triggers the fuse element in response to an overcharge or overcurrent condition from a battery pack. 


SCF is a three-terminal, surface-mounted device

The SCF is a three-terminal, surface-mounted device. Image used courtesy of Mouser

To achieve this, the SCF products are all three-terminal devices consisting of a single control terminal and two fuse terminals. In practice, a control signal from the external circuitry is applied to the control terminal and works to activate the heating element inside the SCF. When the heating element is activated, the internal fuse is triggered and cuts off the operation of the system. 


Offerings in the SCF Family

Meant to fit the needs of a variety of different devices, the SCF family comes in a number of different options. Specifically, the devices come in 83 different variants, each varying in package size, DC resistance, operating voltage, and current rating.

According to Eaton, the SCF series is designed to operate with a wide range of current ratings and low internal resistance, making them highly efficient for lithium-ion battery packs. With this series, Eaton offers one of the most comprehensive portfolios of self-controlling fuses for series connections of up to 24 lithium-ion battery cells.

Within this, current ratings range from 12 A to 45 A, while package sizes can vary from 4.0 mm x 3.00 mm x 1.0 mm to 9.5 mm x 5.0mm x 2.3 mm.


Rutronik Offers Three Designs

Rutronik is offering Eaton’s SCF solutions as part of its lineup of products. Specifically, the company will offer the three SCF families, SCF4030, SCF5432, and SCF9550


SCF4030, SCF5432, and SCF9550

Top to bottom: SCF4030, SCF5432, and SCF9550. Image used courtesy of Rutronik

The SCF4030 family is available in 4.0 x 3.0 mm footprints and is rated for a current range of 12 to 22 A; the SCF5432 comes in a 5.4 mm x 3.2 mm footprint and is rated a current range of 12 to 30; and the SCF9550 family comes in a 9.5 mm x 5.0 mm footprint and is rated for current ranging from 30 to 45 A.

With each of these families now available to Rutronik customers, Rutronik hopes they can enable their customers to build the next generation of battery-powered devices such as e-bikes, robotics, and consumer tech.