CAP-XX has developed the industry’s first 3V thin, prismatic supercapacitors. The company will deploy its 3V Source: CAP-XXtechnology first in thin prismatic form to meet the demand for small, inexpensive, energy-efficient power solutions for thin wearables, key FOBs and other internet of things devices. CAP-XX will then integrate the 3V technology into its larger prismatic supercapacitors, automotive modules and other products for high-energy, high-power applications.
The new 3V supercapacitors eliminate the cost and inefficiencies of the low-dropout (LDO) voltage regulator or buck converter often required to step the voltage down to work with the industry’s existing 2.7V-rated thin, prismatic supercapacitors. CAP-XX is initially targeting markets using 3V coin cell batteries, where popular batteries such as the CR2032 have reasonable energy (~220mAh) but have trouble delivering the peak power (~100mA) needed for data collection and transmission. CAP-XX can handle those power bursts, and its new 3V supercapacitors can be placed directly across the battery without the intermediary LDO.
To achieve the 3V, CAP-XX developed new materials and production techniques. The company has successfully tested prototypes at 3V, 70°C that meet the IEC 62391 requirement for endurance. CAP-XX has started production trials, with samples expected for customers by end of August 2018, and mass production in the first half of 2019. Pricing will start at less than US$1 in large volumes. CAP-XX will become the only manufacturer to provide a 3V supercapacitor in a thin, prismatic form factor.
The 3V versions, ranging from 0.9mm to 1.9mm thick, will come in the same footprints as CAP-XX’s existing 2.7V thin prismatic supercapacitors: Z, 20mm x 15mm; A, 20mm x 18mm; W, 17.5mm x 28.5mm; S, 17.5mm x 39.5mm. Initial samples will be in the S package, with other footprints and the 0.6mm Thinline products to follow.
Specific benefits of the 3V supercapacitors over 2.7V cells that require an LDO:
- Cost savings of US $.27 to $.31, or 20 to 25 percent, based on a single supercapacitor price of US $.95 to $1
- Saved battery energy, up to 30 percent over five years. Assuming constant power, an LDO dropping the battery voltage from 3V to 2.7V will lose 10 percent of the battery energy. On top of that, assuming the LDO draws 1µA, an additional 8.8mAh (4 percent of a typical CR2032’s energy) is lost per year. The projected yearly energy savings therefore is: 10 percent + 4 percent = 14 percent after one year, 10 percent + 8 percent = 18 percent over two, 22 percent over three and 30 percent over five years.
- Increased usable energy storage. For example, if an application operates down to 1.8V, then a 3V supercapacitor stores 42 percent more usable energy than a 2.7V one.
- Improved power density, by 23 percent.
- Low leakage current, approximately 1.5µA for a 500mF cell at 3V. As the battery discharges and voltage reduces, the supercapacitor leakage current also reduces to about 0.7µA at 2.5V.
Engineers might also consider a buck converter or a buck-boost design if the current required is only marginally more, say +20-30 percent , than the coin cell can provide. CAP-XX projects that its 3V supercapacitor solution will be up to 50 percent cheaper than such a design. CAP-XX also projects such a design will still incur significant energy losses, as it won’t see the benefits of the higher currents from a 3V supercapacitor, and it will require more components.