Mastering miniaturisation with hybrids

Advances in the IIoT, process digitalisation, and automation demand the increasing integration of electronics into industrial applications. Key factors driving the need for more robust capacitor solutions are maximum reliability and the stable performance of all components. Conventional capacitor technologies are less than ideal for applications in challenging operating environments and may even pose a significant safety risk.

• Premature failure caused by liquid electrolyte drying out
• Increased space requirements and higher costs when using larger capacitors to offset derating
• Fire hazard caused by short circuits and equipment failures caused by defects or breaks in the oxide layer

Polymer hybrid aluminium capacitors bring together liquid, conductive polymers as an electrolyte with an aluminium cathode. This technological approach combines a number of advantages. The polymer offers high conductivity and a correspondingly low ESR value. The liquid component of the electrolyte, on the other hand, can withstand high voltages and offers higher capacitance values due to its large effective surface area. The voltage range of the hybrid capacitors is from 25 to 80V, with capacitance values between 10 and 1000μF. And while the ESR values of 8 to 120mΩ are higher than in other polymer capacitor variants, they are still very low.

Hybrid models are ideal for applications in computer services, backup devices, networking equipment, industrial motors, automotive engine control gear, inverters, security cameras, and specialty lighting.

• Outstanding frequency characteristics: The low ESR values ensure low impedance close to the resistance point, reducing AC ripple in circuits.

• Stable capacitance: In ceramic capacitors, changes in the operating temperature or DC bias voltage result in a change in capacitance. However, effective capacitance losses also mean an often significant fall-off in performance. This does not affect polymer hybrid capacitors, which maintain stable capacitance even in non-standard operating conditions – i.e. at high frequencies and low temperatures.

• Reliability in demanding environments: Hybrid capacitors are more durable and have better moisture resistance than their electrolytic or polymer counterparts. They also offer significantly higher tolerance to large ripple currents, inrush currents, and high temperatures.

• Small footprint: Surface-mountable hybrid capacitors – for a 48V power supply application, for example – use 87% less space than standard aluminium electrolytic capacitors on a PCB.

• Self-healing for improved safety: In polymer capacitors, self-healing is initiated as a response to Joule heating, which occurs when a dielectric defect creates a short circuit. This heating breaks the molecular chain of the conductive polymer near the defect, increasing the polymer’s resistance and effectively forming a barrier to any current leaking from the electrode. Hybrid capacitors, however, have an additional self-healing mechanism: to reoxidize the aluminium, the liquid electrolyte causes current to flow near the defect.

All together, these properties point to a clear overall cost advantage when using hybrid capacitors, despite their higher price point. The higher ripple current specification alone, with the extended service life of the capacitor, can lead to cost reductions of 20 percent.

At Schukat electronic, we offer fast, competent support when selecting the capacitors best suited to your application. With our inventory of Panasonic polymer and hybrid capacitors, we support the realisation of automotive and industrial applications with the highest levels of reliability and safety, as well as an economically attractive TCO. Working with Schukat means personal, specialist contacts, a swift response to enquiries, and the provision of data sheets and samples. From our automated logistics centre in Monheim am Rhein, we ensure high availability at short notice to cover your needs – for high volumes, too.

Our sales team can advise on selecting the right component and on customer-specific questions relating to capacitors.