Shin-Etsu Chemical has developed a silicone rubber for molding that is optimal as an insulation covering material for onboard high-voltage cable in automobiles

This new product realizes significant improvements in flexibility and lighter weight for high-voltage cable


Shin-Etsu Chemical Co., Ltd. (Head Office: Tokyo; President: Yasuhiko Saitoh) has developed a new silicone rubber for molding (the “KE-5641-U”) that is optimal as an insulation covering material for high-voltage cable used in automobiles.

In the case of electric vehicles (EVs) and hybrid electric vehicles (HEVs), their drive systems increasingly require higher-voltage/larger current cable. Because of this, high withstand voltage characteristics are being sought after for high-voltage cable for EVs and HEVs. Accordingly, when the currently existing insulation covering material is used in order to secure the insulation’s performance, the covering layers of the cable become too thick and the cable becomes inflexible and therefore problematic to handle and to route through the interior of a vehicle. Thus, automobile manufacturers are seeking high-voltage cable that has superior flexibility that makes wiring easier to handle.

Developed by taking advantage of our company’s unique technologies, Shin-Etsu Chemical’s new silicone rubber for molding product, the KE-5641-U, will help facilitate the solution of these issues. With this new product’s high withstand voltage characteristics, even when the high-voltage cable’s insulation system covering layers are made thinner, superior insulation performance is secured. In addition, the thinness of the covering layers leads to a significant improvement in the flexibility of the cable, and at the same time, it realizes a thinner diameter and lighter weight high-voltage cable.

The product’s main characteristics are as follows:

  1. It realizes the industry’s top-level high dielectric withstand voltage (DWV) characteristics. Its dielectric breakdown strength is 40kV/mm — our currently existing product’s strength is 26kV/mm.
  2. Because it is made of silicone rubber, this new product has combined many superlative characteristics, such as b resistance to heat and cold, weatherability and flame retardancy.
  3. Compared to non-silicone type insulation covering materials, it is stellar in long-term reliability.

In addition to its usage for vehicles, the new product can also be used as an insulation covering material in high-voltage cables for applications in such fields as industrial machinery, railroad equipment, and energy plants, and it will contribute to higher performance and improved reliability.

Shin-Etsu Chemical will continue to endeavor to enhance our ability to contribute to the solution of various social and customer issues. We will work toward the achievement of this goal by developing and supplying advanced functional silicone products through making full use of the technological power and knowhow that Shin-Etsu has nurtured up to now, as we strive to further contribute to the realization of the sustainability of society.

■Reference Material

High-voltage cable used in an electric vehicle

High-voltage cable used in an electric vehicle

Image of wiring of a high-voltage cable used in an EV

Image of wiring of a high-voltage cable used in an EV

For inquiries about this matter, please contact

    • Shin-Etsu Chemical Co., Ltd.
    • Public Relations Dept.
    • Tetsuya Koishikawa
    • Tel: 03-6812-2340, or from outside Japan: 81-3-6812-2340
    • Fax: 03-6812-2341, or from outside Japan: 81-3-6812-2341
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