Kobe Steel develops KCAR™44 new copper alloy for resistors
Jun. 12, 2026
Kobe Steel, Ltd.
Kobe Steel, Ltd. has developed KCAR™44 (Cu-Mn-Ni system)*1, a new copper alloy intended for shunt resistors applied in current detection. Sample shipments to customers have commenced for evaluation purposes.
With the increasing popularity of xEVs (electrified vehicles) and ongoing advancements in industrial and social infrastructure, demand for highly efficient and precise power control and management has been rapidly increasing in recent years. Meanwhile, conventional resistor materials have, in some cases, exhibited instability under high-temperature conditions.
The newly developed KCAR™44 features a temperature coefficient of resistance*2 of ±20ppm/K (20-50℃), indicating minimal resistance fluctuation under temperature changes. This enables stable and accurate current measurement, even when the operating environment temperature varies. Additionally, it demonstrates a volume resistivity*3 of 44 μΩ·cm (typical value), maintaining resistance characteristics equivalent to those of conventional shunt resistor materials. This allows for application without significant modifications to existing designs. Another key feature is its enhanced stability in high-temperature operating environments.
| Item | KCAR™44 |
|---|---|
| Electrical resistance | ○ Equivalent to conventional copper alloy |
| Stability of electrical resistance under temperature changes | ○ Equivalent to conventional copper alloy |
| Stability of electrical resistance in high-temperature environments | ◎ Its enhanced stability in high-temperature environments is expected to offer greater design flexibility for resistors |
KCAR™44 is intended for automotive applications, including battery management systems (BMS) and electric compressors, as well as for industrial uses, such as power modules, power supplies, power tools, server power supplies, and more.
We will continue to contribute to the realization of a society where electrical energy is used more efficiently and safely by promoting technology that harnesses the unique features of KCAR™44.
Kobe Steel Group (also known as the Kobelco Group) is advancing transformation initiatives to become a more appealing company for stakeholders under its current medium-term management plan (Fiscal 2024–2026). To realize this, the Group is promoting transformation initiatives, collectively called KOBELCO-X*4.
This development not only enhances competitiveness in existing applications by improving stability in high-temperature environments while maintaining the characteristics of conventional materials but also enables us to meet new market demands in fields such as xEVs and power supply systems. This is an example of AX (ambidexterity)—contributing to both enhancing earning power and pursuing growth.
Through the integration of our distinctive technologies, products, and services, we will continue to provide solutions to the needs of society, striving to realize a world in which people, now and in the future, can fulfill their hopes and dreams while enjoying safe, secure, and prosperous lives.
- *1KCAR stands for Kobelco Copper Alloy for Resistor.
- *2Temperature coefficient of resistance indicates how stable a material’s electrical resistance is under temperature changes.
- *3Volume resistivity indicates how strongly a material resists electric current flow.
- *4KOBELCO-X is a collective term of our Group’s seven transformation initiatives aimed at achieving the transformation into an appealing company.
KOBELCO-X reference material: Our Group’s Transformation Initiatives[PDF:7.86MB]
- *The information on this web site is presented "as is." Product availability, organization, and other content may differ from the time the information was originally posted. Changes may take place without notice.
