Energy density and power density are essential, yet unique, metrics. Understanding the differences between them is crucial for designing efficient energy storage solutions. This blog explores those differences and their impact on capacitor performance.

Capacitors are essential passive components for designing any electrical circuit. But there are so many options to choose from with a wide range of specifications that it can be overwhelming to determine what capacitor may be the best fit for your application. One early decision that circuit designers must make is to determine if a single-layer capacitor (SLC) or multi-layer ceramic capacitor (MLCC) is the right fit for their application needs. 

To protect electrical grids from overloads and faults, utility companies can incorporate reclosers. When a fault occurs, this high-voltage circuit breaker automatically closes to isolate the faulty sections of the grid, allowing other areas of the grid to continue to operate safely. The recloser can then automatically test the electrical lines to determine if the issue has been resolved and reset itself, restoring power more quickly once a fault is cleared. Reclosers are also designed to perform remote switching, enabling utilities to manage their networks more efficiently.

Energy storage capacitor banks supply pulsed power in all manner of high-current applications, including shockless compression and fusion. As the technology behind capacitor banks advances with more precise switching and higher energy density, fast discharge capacitors can reliably support more advanced applications.  

Standards are a form of technical infrastructure, and their influence is felt throughout the electronics industry. For example, formed in 1924, the Electronic Industries Alliance (EIA) was an American standards organization that established an alliance of trade associations in the United States electronics manufacturing industry. Their collaboration ensured that electronic equipment produced by different manufacturers was compatible and interchangeable. The EIA formally dissolved in February 2011, dividing by sector.

Product designers working on critical applications requiring electrical power must carefully select components that not only supply the appropriate amount of voltage at the right time, but also help mitigate issues such as voltage ripple, ensure system longevity, and improve component reliability. 

In a short period of time, artificial intelligence (AI) large language models (LLMs) like ChatGTP and Claude have made leaps and bounds in terms of their size and sophistication. Size, as measured by the number of parameters, has increased by a factor of one thousand in merely five years, and it’s not projected to stop (Figure 1). This rapid growth raises numerous questions about the future of AI, while also presenting immediate challenges, with power consumption being a significant concern.  

In power electronics, rectification is the conversion of alternating current (AC) to direct current (DC). After the AC signal enters a rectifier circuit consisting of power diodes, the resulting raw rectified waveform yields a series of half sine waves with significant ripple. In order to minimize the pulsating DC voltage, a smoothing capacitor is placed in parallel with the load across the rectifier output. As the rectifier voltage rises, the capacitor charges and stores energy like a reservoir. Then when the rectifier voltage falls, the capacitor discharges, greatly reducing the ripple voltage.

Supercapacitors feature unique characteristics that set them apart from traditional batteries in energy storage applications. Unlike batteries, which store energy through chemical reactions, supercapacitors store energy electrostatically, enabling rapid charge/discharge cycles. In certain applications, this gives them a significant advantage in terms of power density, lifespan, efficiency, operating temperature range and sustainability.  

In an ideal world, capacitors could be designed in a way where they would exhibit no resistance. However, this is physically impossible to achieve as there will always be some type of internal resistance in a capacitor that appears in series with the capacitance of the device. Known as equivalent series resistance (ESR), the level of this resistance will vary across capacitors depending on a variety of factors including the dielectric materials used, frequency of the application, leakage, and quality and reliability of the capacitor. The two graphs in Figure 1 show an example of how ESR can change as frequency increases across various capacitances on two different classes of ceramic dielectrics.