Supercapacitors
Supercapacitors, uniquely among all storage devices, store electricity in the form of electricity. By contrast, batteries store electricity in the form of chemical energy. Therefore, both the storage and use of electricity is much faster, and more efficient, in supercapacitors than in batteries. Supercapacitors have much longer life and use much safer materials than batteries. See below for a comparison of supercapacitors and batteries.
A Survey of Energy Storage Devices
| Supercaps | Lead Acid | Ni-MH | Li-Fe-P | |
|---|---|---|---|---|
| Power Density (W/kg)90% | 5695 | 146 | 393 | 897 |
| Energy Density (W/kg) | 5.5 | 40 | 60 | 115 |
| Cycle Life | >200,000 | 500 | 500 | 500 |
| Changing Time (Seconds) | 01-30 | 3000 | 3000 | 3000 |
| Temperature(C) | -40 to 70 | -20 to 45 | -20 to 50 | -20 to 50 |
| Heavy Metals | None | Yes | Yes | Yes |
Pulse applications such as communication, and acceleration/braking in Electric Vehicles drain batteries much more quickly than other use. Today, most battery-operated devices include at least one pulse communication app. This means that your battery drains much faster than as designed. Additionally, most batteries while performing well at 21C, drain even faster at lower and higher temperatures. By using a supercapacitor, you not only get more time between recharging, better performance at higher (45C ) and lower temperatures (-20C), but also increase the battery life 2x to 4x!
Why OptiXtal Supercapacitors?
OptiXtal offers the smallest form factor in the industry, enabling you to use a smaller battery and/or one with less power. We can custom build supercapacitors that will fit your empty space, thus allowing you to expand your battery life without undergoing expensive package re-design.
What makes our supercapacitors unique:
- Ultra-Thin: Less than 1 mm thick
- Flexible
- Twice the capacitance of comparable products for the same footprint
- Half of the leakage current of comparable products
- Customizable
With all these qualities combined, our supercapacitors are highly competitive contenders on the market.
Powering IoT
Recall that an integrated IoT device contains 1 or more sensors, communication, power storage, and a micro-controller all preferably in a small enough footprint to be deployable in many locations. Usually, the largest of these is the power storage component. So for the final device to have a small footprint the power storage component not only must be small but its form factor also must be compatible with the rest of the IoT device. Consider, for example, a postage-sized device powered by a cylindrical AA cell type battery. The battery makes the device too bulky and perhaps difficult to deploy in many applications where blending with the background is important.
This recognition of the value of a thin form factor initially led designers to use thin film Lithium Ion batteries for IoT applications. It was thought that the thin form factor, and their large energy storage capacity could potentially power the low energy use IoT devices for 10 years or more. The trouble was that when deployed in the field, these batteries were not able handle pulse power-whether for communication or for actuation.
Close to 95% of installs in the field fail because of this weakness of the battery (to handle pulse power). Several workarounds such as upsizing the battery to allow for larger pulse loads were tried to resolve this issue. The large pulse loads on the batteries, and the extant high/low temperatures in the field also led to reduction in battery life. The use of the battery also led to additional circuitry because care must be taken to limit current draw during discharge and current input during charging.
OptiXtal decided to attack this critical problem of powering IoT devices from a different angle. We already had a form factor energy storage device with a long life (20 years or so), could handle much higher pulse currents, and required a simple circuit because we did not have to protect the supercapacitor from pulse currents during charge or discharge. The only two issues we needed to solve were: could we find a partner to design ultra-low power circuitry that consumed very little during standby? And could the leakage current of the Supercapacitor be small enough to trickle charge it even in low light conditions (flux less than 50 lumens)?