Polymeric monolithic capacitor

Abstract

Prismatic polymer monolithic capacitor structure that includes multiple interleaving radiation-cured polymer dielectric layers and metal layers. Method for fabrication of same. The chemical composition of polymer dielectric and the electrode resistivity parameters are chosen to maximize the capacitor self-healing properties and energy density, and to assure the stability of the capacitance and dissipation factor over the operating temperature range. The termination electrode that extends beyond the active capacitor area and beyond the polymer dielectric layers has a thickness larger than that used industrially to provide resistance to thermomechanical stress. The glass transition temperature of the polymer dielectric is specifically chosen to avoid mechanical relaxation from occurring in the operating temperature range, which prevents high moisture permeation (otherwise increasing a dissipation factor and electrode corrosion) into the structure. The geometry and shape of the capacitor are appropriately controlled to minimize losses when the capacitor is exposed to pulse and alternating currents.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation in part of U.S. patent application Ser. No. 16 / 035,475 filed on Jul. 13, 2018 and now published as US 2018,0342353, which is a continuation-in-part of U.S. patent application Ser. No. 15 / 625,282, filed on Jun. 16, 2017 (now U.S. Pat. No. 10,102,974), which in turn is a continuation-in-part of U.S. patent application Ser. No. 15 / 483,780, filed on Apr. 10, 2017 (now U.S. Pat. No. 10,347,422)), which is a continuation of U.S. patent application Ser. No. 14 / 668,787 filed on Mar. 25, 2015 (now U.S. Pat. No. 9,711,286). The disclosure of each of the above-mentioned applications is incorporated by reference herein.TECHNICAL FIELD[0002]The present invention relates generally to polymeric monolithic capacitors and, in particular, to capacitors produced using a non-thermoplastic submicron thick polymer dielectric, chemically configured to maximize self-healing and minimize moisture absorption, along with aluminum ...

AI Technical Summary

Benefits of technology

The invention provides a metallized polymer capacitor that is created in a vacuum and includes layers of polymer and metallized electrodes. The capacitor has two electrodes, one of which has a thicker portion in the active area and a thinner portion in the termination area. The thinner portion has low resistance to allow for a self-healing process. The capacitor has mechanical strength and low electrical resistivity.

Problems solved by technology

A major limitation of MFC capacitors is that the film must be thick enough for adequate uniformity and strength to be further handled for metallization, slitting, and winding into capacitors.

However, the degree to which the thickness of the PP film can be reduced is limited by the film-manufacturing process, and the resulting thickness of PP films is typically no less than about two microns.

Therefore, lower voltage applications (such as those specified at 25 V-50 V) that require large capacitance and small size cannot use PP film capacitors.

Metallized PP capacitors that are almost exclusively used in such DC-link applications have an operating temperature limited to 105° C. with significant derating in voltage, ripple current and capacitor lifetime and, furthermore, PP capacitors are relatively large and costly.

Since new power semiconductor devices are now operating at higher temperatures and frequencies, the heat load to the capacitors is increased, thereby imposing additional constraints on the operating conditions of a given capacitor.

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