Category Archives: Energy Storage

Easy As Breathing: The Lithium-Air Battery

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By: Michael Nechayev, Danson Nguyen

Imagine if your car never required any fuel and could drive hundreds of miles at a time, powered only by the atmosphere it moves through. With such a vision in mind, launched its 500 project in 2009, striving to produce a lightweight -air battery that could a car for 500 miles [1]. In this battery, lithium would be reacted with a stream of pure oxygen to produce lithium oxide and electrical energy to the vehicle. Now, in 2012, the first successful prototypes are stirring up considerable hype – and some skepticism – in the scientific community. Nevertheless, despite critics’ doubts and remaining technological hurdles, IBM predicts the battery to be commercially viable by 2020 or 2030 [3].

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Building a Battery with a Spray Gun

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By: Iris Lee, Nida Rukhshi, Andrew Luong, Shoumik Pennathur

The concept of hybrid PV- devices has been explored and investigated by several universities and research institutes around the world; however, Rice University engineers have recently introduced a paintable that has the potential of revolutionizing future energy storage.

Researchers at Rice University in Texas have recently succeeded in inventing a rechargeable ion battery that would enable “a widespread renewable energy capture, storage, and utilization,” according to Rice University engineers [2]. This revolutionary technology is created by tightly rolling up the various battery components in layers before encasing them in a typical rectangular or cylindrical battery packaging. After years of dedicated research, the engineers have come up with a unique version of battery by painting these individual battery components (i.e current collectors, a cathode, an anode, and a polymer separator) onto a select surface in layers. These layers included paints made from oxide (a positive electrode), titanium oxide (a negative electrode) and conductive single-walled nanotubes (a current collector). Another feature that sets this battery apart from the others is the special polymer paint blend that helps the battery achieve superior conductivity by forming the micro-porous layer required in a battery.

This unique approach to battery manufacture yields the possibility of flexible battery technology. The paper, published in Nature Scientific Reports, explains that by breaking down the different components of a battery — the electrodes, separator, electrolyte and current collectors — and rendering them into liquid form that could be painted on any surface, we could revolutionize the way we our devices. Rather than being tied to fixed shapes and sizes, batteries could one day take on practically any form, and be applied almost anywhere including on ceramic, glass, and metal. [3]

The possibilities provided by this new technology are, to some, no cause for celebration or recognition. Many researchers argue the usage of lithium in lithium ion batteries is a misguided endeavor. With most of the known available resources of lithium depleted, many scientists are looking to explore battery storage without the use of lithium. Some even at UC Berkeley are researching batteries composed of different metals such magnesium or zinc. Their criticism may be a little too harsh, as new development in this field has used less and less lithium. Also recycling the known storage of lithium has made the lithium ion battery a possible long-lasting method to store energy. For now, only time will tell if the painted batteries can penetrate future markets.

References:
1. Sean Patterson. “Spray Paint Battery Could Turn Any Surface Into Power Storage.” http://www.webpronews.com/spray-paint-battery-could-turn-any-surface-into-power-storage-2012-06. (Acessed 12/07/20)
2. Wired UK. “Spray-On Rechargeable Batteries Could Store Energy Anywhere.” http://www.wired.com/wiredscience/2012/07/spray-paint-battery/ (Accessed 12/07/20)
3. Sara Ver-Bruggen. “Spray-Paint Batteries Could Open Up New Energy Storage Applications.” http://www.plusplasticelectronics.com/energy/spray-paint-batteries-could-open-up-new-energy-storage-applications-60152.aspx (accessed 12/07/20)

A Promising Future for Grid Energy Storage

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By: Stephanie Zhou, Gilbert Yang, Zain Nayer, Matthew Liu

Many renewable energy sources, such as wind or , are discontinuous and unpredictable. They produce variable , making it difficult to adapt to sudden demands in , or becoming wasteful at times when there is low demand. Enter Isentropic’s pumped electricity storage (PHES). PHES is a “highly reversible, gas cycle machine that works as both an engine and a pump. [3]” The technology seems to be promising and may be deployed in several -grids soon.

Isentropic employs pumped heat electricity storage to store electricity in thermal form. PHES requires a highly reversible heat engine to pump heat between two storage vessels containing gravel. [4] To complete this cycle, electricity is inputted into the machine to compress air in the first storage container, bringing its temperature up to 500  degreesCelsius, while the air in the second storage container is expanded to bring its temperature down to -160  degreesCelsius.  In order to recover the energy, PHES utilizes thermodynamic principles to reverse the heat engine.  This is done by returning energy in the form of heat back through the engine to the cold container, which powers a generator from which electricity is recovered.  At the end of this reversible process, both of the storage containers return to their original temperature.  In short, PHES uses the difference in temperature between the two containers to run the system as a heat engine. [3]

Isentropic claims that this process is highly efficient, ensuring a round-trip efficiency of 75 percent.   In addition, this process is also highly reversible, meaning it is able to retract most of the electricity inputted by recovering the energy through the temperature difference.

As the claimed efficiency approaches the Carnot limit, the theoretical maximum efficiency a heat engine can attain, Isentropic’s PHES provides an attractive alternative to current technology.  The temperatures used in the system are low enough for the system to be built and insulated with common materials, yet the large gap between the two vessels allows a high efficiency.  With limited knowledge of the piston technology being used, it can be tentatively said that the low-tech nature of PHES would allow such a system to be far cheaper and have a lower upkeep than competing technologies. [5]

Isentropic’s PHES technology arose from a need for a more efficient way to store renewable energy, especially those obtained from wind, solar, and power generation. Currently, renewable energy resources are wasted whenever they are not needed – if there is low demand, the excess energy is wastefully dumped. The prevailing method of , pumped hydro, is geographically dependent. Pumped Heat Electricity Storage was designed to be more cost-effective as well as safer than other forms of , since it would not release toxic chemicals to the environment. [3] Other benefits include inexpensive, quick, and easy set-up in an amalgam of locations [1].

Isentropic is not the only company thinking about using gravel to store energy cheaply – in March earlier this year, Bill Gates announced his investment in the startup company called Energy Cache. Its president, Aaron Fyke, has tried to develop a new method of energy storage that did not use the power grid system, which was notable for being unable to efficiently balance energy supply and demand. He arrived at the idea of using gravel, which has properties of both a liquid and a solid. This would replace the typical method of pumping water (pumped hydro energy storage) up a hill wherever and whenever energy is needed [2].

Bibligraphy

[1] Ferenbacher, K. The New Hotness In Energy Storage: Gravel. [Online] June 12, 2012. http://gigaom.com/cleantech/the-story-of-energy-cache-a-drop-dead-simple-energy-idea/ (accessed July 6, 2012).

[2] Ferenbacher, K. The Story of Energy Cache, a Drop-Dead Simple Energy Idea. Gigaom. [Online] March 27, 2012. http://gigaom.com/cleantech/the-story-of-energy-cache-a-drop-dead-simple-energy-idea/ (accessed July 6, 2012).

[3] Isentropic Ltd – Energy Storage. http://www.isentropic.co.uk/energy-storage (accessed July 6, 2012).

[4] Howes, J. Technical Insights. http://www.growthconsulting.frost.com/web/images.nsf/0/7B9CF0B5053E23726525775B0036301E/$File/PSJul10TI.htm (Accessed July 2012)

[5] Greentech Media, Inc. Energy Storage Medley: Hydrogen, CAES, Li-ion, NaS, NiCad….

http://www.greentechmedia.com/articles/read/Energy-Storage-Medley-Hydrogen-CAES-Li-ion/ (Accessed July 2012)

Ultracapacitors

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By: Jennifer Hwang, Wenyuan Bao

During an era where scientists are investigating greener sources of , ultracapacitors have emerged, with enormous storage capacity compared to batteries. Ultracapacitors function similarly to capacitors, gaining potential energy from the buildup of opposite charges on the two plates. Because capacitance (capacity of ) rises in proportion to increased surface area of plates, scientists are seeking to maximize the surface areas of capacitor plates. To do so, scientists coat the metal plates with spongy, porous material, known as , which increases the surface area by 10,000 to 100,000 times. Then, the plates are immersed in an electrolyte of positive and negative ions dissolved in a solvent known as , a polarizable insulator which increases the surface charge in a capacitor and hence, capacitance (ScienceDaily).

A potential, greener replacement of activated carbon is , a byproduct resulting from the burning of organic matter; thus, as fuel consumption increases, production also increases. Because is nontoxic, easily disposed of, and  less costly than activated carbon, it is a more sustainable material that can increase surface area of the plates.  By using instead of activated carbon, producers can drive down the cost of  ultracapacitors, leading to integration of ultracapacitors into more devices, such as electronics (Supercapacitors).

There are several disadvantages associated with ultracapacitors.  Most ultracapacitors offer lower voltage than standard batteries, so a series of ultracapacitors is needed to have voltage equal to a .  Also, voltage across an drops significantly as the discharges, so voltage is unsteady.  Furthermore, ultracapacitors have very low internal resistance compared to standard batteries; if the circuit is shorted, ultracapacitors will discharge very quickly and create sparks, creating a fire hazard (ScienceDaily).

However, ultracapacitors, if further developed, could store as much energy as batteries and avoid the environmental threat of poisonous metals (nickel, , mercury) used in batteries. Furthermore, the coupling of ultracapacitors with fuel cells would popularize environmentally-friendly, fuel-efficient automobiles (GigaOm).

In the future, ultracapacitors, which effectively provide sudden surges of energy, could be coupled with batteries in many electronic devices. For example, in electric cars, ultracapacitors could provide for acceleration, and the battery could provide range. Ultracapacitors could also provide surges of during stops and starts of cars. In addition, on  electric grids, ultracapacitors could be set up to absorb surges, allowing transmission lines to operate closer to 100 percent capacity, which would be more cost-friendly than adding new transmission lines. Therefore, with further development, ultracapacitors could eventually replace batteries in certain devices, providing a more efficient, durable storage device (WorldandI).

References

Graphene Supercapacitor Breaks Storage Record. Physicsworld. http://physicsworld.com/cws/article/news/2010/nov/26/graphene-supercapacitor-breaks-storage-record. (accessed: June 11, 2012).

How Ultracapacitors Work (and why they fall short). GigaOm. http://gigaom.com/cleantech/how-ultracapacitors-work-and-why-they-fall-short/. (accessed: June 10, 2012).

Supercapacitors: Cheaper, Greener, Alternative Energy Storage. ScienceDaily.
http://www.sciencedaily.com/releases/2011/05/110523101909.htm. (accessed: June 10, 2012).

Ultracapacitors Challenge the Battery. WorldandI. http://www.worldandi.com/subscribers/feature_detail.asp?num=23938. (accessed: June 10, 2012).