Insulation films for busbar systems


Insulation films for busbar systems

Ahlhorn | 09.09.2020

The expansion of the charging infrastructure in Germany and the higher performance of electric vehicles present new challenges for manufacturers of conductor rails, charging infrastructure and battery systems. High dielectric strength, partial discharge resistance and small component sizes are the requirements of the automotive industry and plant manufacturers for charging stations for electric vehicles.
For highly integrated components with high field strengths, the homogeneity of the applied layer is particularly important, since variations in the layer thickness have a direct effect on the dielectric strength of the material. The dielectric strength is largely dependent on the diameter and dielectric properties of a material.
For the production of multilayer current-carrying systems, film technology is mainly used for the insulation of conductive layers. The film technology is characterized by high homogeneity in the layer thickness. A high homogeneity of the layer is necessary because air inclusions can cause pre-discharges which ionize the surrounding air and make a breakdown more likely. In addition, surrounding insulation materials are permanently damaged by ultraviolet radiation.
The edge area in the foil technology must be reworked. The following methods are used for this:

Open Mould

In the open mold process, the insulator layers overlap the metal layer in the edge area, but do not enclose it, so that the full potential of the different current-carrying layers is present in the side area. Depending on the applied field strength, the air in the edge area is ionized, which can lead to arcs or damage to the material by ultraviolet radiation at higher electrical field strengths. The process is characterized by low manufacturing costs and is designed exclusively for use in switch cabinets and dry applications with low field strengths.


Similar to the Open Mould process, the insulator layer overlaps the metal layer at the edges. The current-carrying layers are sealed by casting compound and subsequent finishing of the edges. Problems can arise due to air inclusions which lead to damage of the insulator by ultraviolet radiation. Depending on the material, the process is designed for higher field strengths.

Closed Mould

In the Closed Mould process, the protruding film is pressed and thus completely seals off the current-carrying levels at the sides. It is important to avoid air inclusions at the edges.
Insulation films from Dr.Dietrich Müller GmbH allow a high degree of freedom in the production of components, depending on the process technology. Particularly in the case of highly integrated high-performance systems, high degrees of freedom play a role in the design. Examples of this are:

– Charging stations for electric vehicles and other systems of the charging infrastructure
– Power regulators, accumulators and charging systems of electric cars and hybrid vehicles
– Vehicle electronics of locomotives, streetcars and electric buses
– Wind turbines and off-shore systems for renewable energies
– High current systems for aircraft
– Power electronics in computer, server and telecommunication systems

Dr. Dietrich Müller GmbH is specialized in the production of polyimide film, electrical insulation materials, thermal conduction products, gaskets and technical films. The product portfolio includes flexible electrical insulation materials, prepregs, coated fabrics, adhesive tapes, laminates and profiles, heat conducting products, technical films, sealing materials, mica products and other product groups.
Materials from third-party suppliers as well as our own patented solutions are used to implement the orders. In addition to our own products, we also offer technical services and consulting.
Primary target markets are the electronics, solar, automotive and cable industries as well as the construction of electric motors, transformers and generators.

Share this post