
TDK Corporation
Film assembly
At least two dielectric films are wound in parallel to form a capacitor element. Fig. 1 shows the film/foil arrangements in a crosssectional view for common PCC designs: the diagram shows the most common standard version with the metallization on one side.
The winding technology
This developed winding technology can be used to implement absolutely flat and wrinkle-free stacked windings in “power cap dimensions” for PCC1) using metallized polymer films, starting with PP down to 2.5 μm and PET of 1.8 μm, Fig. 2, 3. The PCC process flowchart describes the main production steps. The flexibility and extremely high process quality of the production line and the polygon winder (PW) are important for this application.
A special “wavy-smooth” cut combination produces a maximum effective contact surface via a defined small offset and precisely wound master capacitors allowing a specially optimized metal-spraying and contacting process. The result is an outstandingly high pulse-current handling capability far beyond the minimum requirements laid down in IEC and EN standards and without the contact edge problem, a well-known and dangerous constriction effect at the film edges of low-cost MKP windings.