MITSUBISHI MATERIALSCopper & Copper Alloy Business

MITSUBISHI MATERIALSCopper & Copper Alloy Business



Commencement of Mass Production for MSP8 Solid Solution-hardened Cu-Mg Alloy for Large Current Automotive Terminals and Bus Bars

Mitsubishi Shindoh Co., Ltd. (President: Kazumasa Hori; capital: 8.7 billion yen; "Mitsubishi Shindoh") is pleased to announce that mass production has commenced for the MSP8 solid solution-hardened copper magnesium ("Cu-Mg") alloy with the high performance required for high voltage and large current automotive terminals and bus bars*1 in hybrid vehicles and electric vehicles. The MSP8 was jointly developed by Mitsubishi Shindoh and Mitsubishi Materials Corporation (President: Naoki Ono; capital: 119.4 billion yen).

Amid the prospect of the worldwide expansion of hybrid vehicles, electric vehicles and other environmentally friendly vehicles, the market for high voltage terminals, bus bars and other electric conductive materials for high voltage and large current applications are expected to expand steadily. Mitsubishi Shindoh has offered MSP8 samples mainly for electric conductive materials to customers since 2016. The MSP8 has been highly regarded for its high performance and reliability.

The MSP8 offers the following features.

  1. Outstanding electric conductivity
    A high level of electric conductivity, equivalent to 80% that of pure copper, helps suppress heat generation with electricity supply.
  2. Enhanced stress relaxation resistance properties*2
    Boasts highly effective properties against the fatigue of springs operated at high temperatures (stress relaxation) that significant interlocking connection force*3 between male- and female-type terminals is maintained under high-temperature conditions. It thus provides high reliability for supplying electricity.
  3. High levels of stamping workability and material strength
    It holds superior stamping workability and material strength that enable processing into accurate dimensions required for electric conductive materials.

Mitsubishi Shindoh has been manufacturing and selling the MSP series of high-performance, solid solution-hardened Cu-Mg copper alloy. In the series, the MSP1 has been highly regarded for its use in automotive terminals, bus bars and relays for a long time. The MSP5 has been adopted by many manufacturers as copper alloy for automotive electronic and electric equipment in recognition of its properties suitable for small-sized terminals, such as high strength and bend workability and low specific gravity. Now, the MSP is joined by the MSP8, ideal for high voltage and large current applications, such as bus bars, relays and high voltage terminals, to help accelerate the introduction of electric equipment to next-generation vehicles.

Mitsubishi Shindoh and the Mitsubishi Materials Group aim to become the leading business group committed to creating a sustainable world through material innovation using unique and distinctive technologies for People, Society and the Earth in accordance with the long-term management policy. The group will continue to contribute to society through product development based on original technologies.

*1 Bus bar:
It is an electric conductive component that connects a power source to different parts mainly on switchboards and control panels. It is chiefly made of copper.

Figure 1: Application example in a small-sized junction box
(The components marked with arrows are bus bars.)

*2 Stress relaxation resistance properties:
Stress relaxation resistance properties are an indicator of the spring property during long-hour use at a high temperature. It shows the level of resilience of a spring without deterioration, for instance, after it is kept under a load within the elastic deformation limit under which its spring property is exhibited for 1,000 hours at 150℃.
As illustrated below, a spring made of alloy with high stress relaxation resistance properties does not weaken after being used at a high temperature. It provides a sufficient interlocking connection force between the male- and female-type terminals. A spring made of alloy with poor stress relaxation resistance properties weakens after use at a high temperature. It produces a poor interlocking connection force between the terminals. In this state, electrical contact between the two terminals may be hindered by vibrations and others.

Figure 2: Relationship between the interlocking connection of terminal connectors
and stress relaxation resistance properties

*3 Interlocking connection force:
It is a connection force between male- and female-type terminals interlocking with each other on connectors based on the terminal dimension difference. In Fig. 2, the spring in the female-type terminal supplies force for connection with the male-type terminal.

Please inquire here for any questions.

Press Release