When I first heard about paper batteries, I was skeptical. I have worked with companies that had batteries on mylar and similar materials, but paper?
I was intrigued, so I agreed to speak to Shreefal Mehta, CEO, and Dave Rich, Senior Director, at The Paper Battery Company.
The company started in 2008 and is based in upstate New York (RPI grads). Its vision was roll to roll print production of scalable, flexible, structural sheets of energy storage material. The technique would be producing both battery and supercapacitor (energy and power) material on the same high volume print production line.
It is now developing ultrathin supercapacitor technology that it claims will enhance battery performance in mobile devices and other products that rely on traditional rechargeable lithium batteries. The technology is unique, relatively non-intrusive (just .3mm thick), works with existing battery solutions, and is environmentally friendly. With this scalable technology, energy storage and dispensing can be significantly improved, using a cost- and space-efficient sheet-like product that can easily be designed into a variety of electronic products.
The company saw the trend in embedded devices getting smaller and thinner and running on batteries, so they went off and developed a thin, inexpensive design for a battery. I wondered how good this technology was.
PBC has also announced a partnership with leading battery pack maker TWS -- one of the top five battery suppliers in the world.
So I delved a little deeper, asked questions and did some research.
A "doubting Thomas"
I found that the New University in Lisbon, Portugal, had done a great deal of research and development of paper thin-film batteries constructed on cellulose paper used simultaneously as an electrolyte, separating electrodes, and a physical support of a rechargeable battery1 . As a matter of fact, a 3 V prototype was able to control the on/Off state of a paper transistor.
Then Purdue University, in 2013, created Lithium-ion batteries using flexible paper-based current collectors. The current collectors were fabricated from wood microfibers coated with carbon nanotubes (CNT) through an electrostatic layer-by-layer nanoassembly process2 .
So, OK -- it can be done. Now I was interested in The Paper Battery Company's design.
The Paper Battery Company process
The company's PowerPatch™ product line consists of ultrathin, patternable ultracapacitor devices with interconnects and packaging designed to make compact energy modules with operating voltages ranging from 2V -- 7.8V depending on the desired life time.
This first generation product implements a limited subset of the PowerWrapper™ technology platform and highlights the packaging innovation developed by the company for this next generation of ultrathin, patternable, ultracapacitors.
As a bonus, this design is an environmentally friendly product: Ultracapacitor technology uses electrodes composed of high surface area activated carbon, carbon nanotubes, or graphene. Paper or other porous polymer separators hold the electrolyte and separate the electrodes. Current collectors, usually aluminum foil, attach to the electrodes and carry the charges in and out. The PowerPatch™ products do not have the often-toxic heavy metals typically found in batteries and are RoHS compliant.
Reducing voltage droop
PowerPatch™ Gen2 can significantly decrease voltage droop in a really small space.
Slim form factor makes PowerPatch™ excellent for spreading and shielding heat. PowerPatch™ is architected to be EMI “quieter” and to serve as an RFI shield.
Applications made possible with this technology
- Capacitive touchscreens3 -- Noise (EMI) is the number one issue for capacitive touchscreens, and the PowerPatch can not only act as a shield but also provide for LED Driver voltage stability.
- Camera flashes -- Most phone cameras with greater 1.3MP require strong flashes for images and bright torches for movies in lower lighting conditions. The intensity of the flash directly and indirectly affects the image quality3 . Power pulses to the flash require high energy and very low ESR.
- Smartwatches -- Currently, smartwatches, while novel, offer limited functionality as a tethered device to a smartphone or tablet. Evolution of functions will require better power sources to extend range and increase data rates.
- Small and battery-powered woofer and subwoofer sound systems -- For the best sound, transient power demands must be accommodated with as little change as possible in the power supply voltage, essentially as changes in current demand only. Supercapacitors with high energy density and low ESR will increase performance. Thin form factor enables them to fit in the industrial design of the final product or bass-producing subsystem.
- Personal audio amplifiers and medical hearing systems -- Integration of Bluetooth and other wireless radio technologies for streaming directly into the device. RFI and Tru-Tone Hearing Aid Centers (THAC) issues.
- LED drivers -- Voltage stability, boost efficiency, thermal and RFI benefits, plus cost and size advantages.
Future growth will be driven by scale production to large format performance laminates, energy wraps as structural elements, like solar energy array backplanes to hybrid vehicle panels.
PowerPatch™ can be implemented with multiple outputs, and in the future, multiple voltages. These advantages allow PowerPatch™ to make power connections adjacent to multiple loads for the lowest possible ESR. PowerPatch™ can be used to multiply or divide voltages to feed directly to load, or as an input to or storage from voltage converters.
In the future, PowerPatch™ will have the ability to mount components directly onto the PowerPatch™. Examples might include components for voltage regulation, switches, and control, as well RFIDs.
For more information visit the Paper Battery Company website.
This article was originally published on EBN's sister publication EDN .
- 1. Self-Rechargeable Paper Thin-Film Batteries: Performance and Applications, Isabel Ferreira, Bruno Brás, Nuno Correia, Pedro Barquinha, Elvira Fortunato, and Rodrigo Martins, Journal of Display Technology, Vol. 6, No. 8, August 2010
- 2. Paper-Based Lithium-Ion Batteries Using Carbon Nanotube-Coated Wood Microfibers, Nojan Aliahmad, Student Member, IEEE , Mangilal Agarwal, Member, IEEE , Sudhir Shrestha, Member, IEEE , and Kody Varahramyan, Senior Member, IEEE, IEEE Transactions on Nanotechnology, Vol. 12, No. 3, May 2013.
- 3. Avoiding EMI in capacitive touch screens