NEW! Electrical Storage Device SMC!
Electrical energy has been stored in electrochemical batteries, capacitors, and double layer or ultra capacitors. Other mechanisms like pumped hydro, thermal systems, and even flywheels store energy that can be used to generate electricity. Surface-mediated cells (SMC) offer us the advantage of increasing both power and energy densities.
Power Density is a measure of how quickly a charge can be transferred. It is typically measured in units of power (watts, KW, joules/second) over weight. Power is what we need in an electric car to start the vehicle moving, to accelerate, and for regenerative braking. Some devices are known for their high power ratings. Capacitors, ultra caps (often measured in mF and Farads) and flywheels are particularly good with power density because the electricity is held as a static charge on the surface of plates or in the kinetic movement of flywheels. There is no intermediate chemical step as there is with batteries. Devices with a high power density will charge and discharge quickly. Hybrids that have an additional energy source particularly need energy storage that has an emphasis on power density.
Energy Density will tell us how long the electricity can continue to flow. It is measured in units of power over time (watt-hours, KW-hr, joules and often for batteries AH) over weight. Within the chemical bonds of batteries a more electrical energy can be stored than is generally available with capacitors or flywheels. Energy density helps to give us the range in an electrical vehicle. Battery electric vehicles (laptops, and cell phones) that don’t have an additional energy source especially need energy storage that emphasizes energy density. This is particularly true in vehicles as the weight of the battery must be carried using the energy stored in the device.
Other important considerations may be the power and energy density over volume, the battery efficiency, the battery cost (often expressed as a fraction with power density or energy density as in cost/KW-hr), the cost of recycling/disposal and life cycles before failure. Battery manufacturers want to increase the energy density but may wish to increase charge/discharge times, which will also increase power density. Capacitor manufacturers want to increase the energy density of their products. There has been an assumption that overall battery qualities could not be improved without some compromise. SMC technology challenges this assumption in this latest of a series of announced improvements with their technology.
The approach taken by Dr. Bor Jang Co-Founder and Chief Executive Officer of Angstron Materials Inc. (privately held; Dayton, Ohio) uses the “exchange of lithium ionsintercalation or deintercalation.” The operation is more like a capacitor than a battery and the power and energy densities reflect this. The device is presently measured at an energy density of 160 Wh/kg/cell and a power density of 100 kW/kg/cell. This might compare with a Tadiran lithium thionyl chloride battery, which offers an energy density of up to 710 Wh/Kg. However, these are primary energy cells and not secondary, rechargable cells. Atomic batteries can have energy densities many times that of chemical batteries.
The highest power densities are not as frequently discussed. The SMC technology claims to achieve 10 times the power density of the highest ultracapacitors. The highest power densities may be useful for military rail guns where a “power source must provide roughly 6.5 million Amps.”
Angstron Materials Inc. is a spinoff from Nanotek Instruments (privately held, you will need Chinese packets to read the website completely). Nanotek Instruments holds several patents, including one for Nanoscale Graphene Plates (NGPs), a less costly alternative to carbon nanotubes. Earlier this year, it received several patents for “Graphite-carbon composite electrode for supercapacitors.” Other than magnitude, it is not clear if the SMC technology is different than a similar technology announced by MIT last year.
Other novel energy storage options include using a “close-coupled, thermopile storage principle” and lithium ion capacitors. Like the SMC, the emphasis appears to be on the power density.
Primary source and photocredit on SMC: Nano Letters
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Here are some outtakes from a PhysOrg article on these new devices…
” The new devices can deliver a power density of 100 kW/kgcell, which is 100 times higher than that of commercial Li-ion batteries and 10 times higher than that of supercapacitors.
The higher the power density, the faster the rate of energy transfer (resulting in a faster recharge time). In addition, the new cells can store an energy density of 160 Wh/kgcell, which is comparable to commercial Li-ion batteries and 30 times higher than that of conventional supercapacitors. The greater the energy density, the more energy the device can store for the same volume (resulting in a longer driving range for electric vehicles).
…, in principle, the SMC can be recharged in minutes (possibly less than one minute), as opposed to hours for Li-ion batteries used in current EVs.”
Although in this study the researchers prepared different types of graphene (oxidized, and reduced single-layer and multilayer) from a variety of different types of graphite, further analysis of the materials and configuration is needed for optimizing the device. For one thing, the researchers plan to further investigate the cells’ cycling lifetime. So far, they found that the devices could retain 95% capacity after 1,000 cycles, and even after 2,000 cycles showed no evidence of dendrite formation. The researchers also plan to investigate the relative roles of different lithium storage mechanisms on the device’s performance.
“We do not anticipate any major hurdle to commercialization of the SMC technology,” Jang said. “Although graphene is currently sold at a premium price, Angstron Materials, Inc., is actively engaged in scaling up the production capacity of graphene. The production costs of graphene are expected to be dramatically reduced within the next 1-3 years.””
http://www.physorg.com/news/2011-08-energy-storage-device-recharge-electric.html
There is some good info about how these devices work to store power. Hope we see some working prototypes soon.
Hope we see some sort of storage which gives us longer EV ranges soon. If we had EVs with 200 mile ranges then we would, I suspect, start kissing the liquid fuel car goodbye.
Thanks Bob, there have been several articles on this starting wih the Nano Letters abstract upon which this article is based. There have also been previous Nano Letters abstracts on this technology starting from last year as well as the MIT announcements of similar technology.
Even though we may have batteries with a high power density and are able to transfer a charge quickly and have batteries with a high energy density we need to have similar technology able to transfer that power/energy to a vehicle. For a discussion of the big battery infrastructure problem and solutions see my article on BYD Edf6 and the EV Range Solution 8/15/11
http://cleantechnica.com/2011/08/15/byd-e6-and-the-ev-range-solution/
While this technology is interesting it doesn’t seem to offer more energy density, more EV range.
IMO the two critical hurdles to EVs being widely accepted are price and range. Price, we are told, will come down as manufacturing levels rise. This seems to be a problem with a built in solution.
Range, then, will be the remaining constraint. People are going to be hesitant to buy a car that they can’t “drive to Grandma’s for Thanksgiving”. One hundred miles is not enough.
Give them two hundred miles (along with the 20 minute rapid (Level 3) recharging we already have and it becomes possible to drive 500 miles a day with only two moderate stops. A rapid recharge will give you an additional 80% range, so drive 200 – stop 20 minutes for a recharge – drive 160 – stop 20 – drive 160. Now you’ve made it over 500 miles with only two meal/coffee/email/pee stops. With a standard gas/diesel car you would have had to stop at least once.
Recharge time is not critical, I suspect. If people can do other things for a few minutes while they get a Level 3 recharge on those few times they drive more than 200 miles I don’t think it will be a turnoff. Most charging is going to be done while vehicles are parked and then rate matters little.
The BYD e6 gets us to 200 miles but with a lot of batteries. If they can get price down low for all those batteries then that may be acceptable, but the real answer is likely more energy stored in smaller batteries. Get that, push prices down, and we’ll move quickly away from gas pumps.
Bob,
I believe a 100-mile range is/would be completely enough (at least for us Europeans) if it is coupled with a 1-5minute 80-100% recharge capability and a 5-10 000 recharge-cycle-life feature.
I would definitely buy a Prius/Leaf sized/priced EV with those parameters. The compromise would be totally acceptable since there would be quite a number of positive factors which are important for me (no annoying engine-noise and vibration, no in-city pollution, much-lower maintenance costs, much-lower running costs…etc)
Bigger range would be nice, but not absolutely necessary.
Sola, there is a chart: “Figure 2. Distribution of daily driving distances.” found in the study linked to the words “the study” on the second page of this article: http://cleantechnica.com/2011/08/15/byd-e6-and-the-ev-range-solution/ I suspect that the distribution would be different in Europe than in America. But it agrees with your belief. In that article the suggestion is made that large batteries are not enough without a concurrent infrastructure to supply large amounts of power to vehicles. Page 2 includes suggested solutions.
Bob, I would tend to agree with your observant point that EV range, based upon existing stats is not necessarily increased. Please forgive me for re-emphasizing several issues and add several not in the article. Other sources have suggested that the road to increased electrical energy storage will not be through chemical batteries but through advancements in super capacitors. The SMC is not exactly a new super capacitor, but it is certainly a close cousin with an obvious future. The stats given are not with optimized materials. There is room for improvement. The devices have doubled in capacity from the first announcements last fall. Time will tell what the ultimate potential can be.
The division between the two companies mentioned seems to be that Nanotek Instruments is holding the intellectual property while Angstron Materials Inc. is producing products. A large part of Angstron Materials effort is to reduce Costs as they have done with NGP. Between increases in capacity and decreases in costs we have more to see from these companies.
Range will continue to be an issue for some who would like to purchase an EV but require a vehicle that can travel further than 100 miles on a charge. Presently cost, weight and charge times limit battery capacity. Some of this I discussed in the BYD E6 article mentioned in my last comment. You seem fairly well informed so probably already know that the Nissan Leaf offers a 30 minute/80% charge.
Having read the BYD E6 article you can now see that “Big Batteries” while popular are not a complete solution to range if charging infrastructure and cost are not also concurrently addressed. I would direct you back to that article for other solutions.
I appreciate your interest and expect to be addressing more of these issues in upcoming articles. Thanks for your thoughtful comments.
There are a lot of things happening in the lab which are likely to improve chemical batteries, innovative anode and cathode designs which are working their way toward the factory. I’d be hesitant to give up on chemical batteries.
Ultracapacitors have been a great disappointment in their ability to hold more power. But even with their space inefficiency I’d like to see them come to market at a better price point. Those like me who are off the grid would love to make a ‘once per lifetime’ storage purchase which UCs offer. We’d be buying something that we could will on to the next generation.
And they would be ideal for those rural areas in less developed countries which are not now served by the grid. They could purchase a small UC which would store enough to give them light and radio at night. Then, once they had a bit more money, they could add additional UCs as they add solar panels. Can’t do that very well with batteries, a weak cell pulls all others down to its level.
If you’re not having to haul your storage around with you then size and weight are less important.
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The 100 mile range issue. I’m looking at a “psychological” barrier to buying an EV. Lots of people could do quite well with only 100 miles but I suspect they think that they actually drive further than they really do. They might drive only 30 miles a day (about the US average) but sometimes drive 80. One hundred would leave them feeling uncomfortable, like when they get in their current car and see the gas gauge a bit under half a tank. They’re not going to burn a half tank that day, but I suspect it weighs on them.
200 miles, to them, is more than daily driving. It’s a trip. They may not take many trips and trips can be taken with ‘the other car’, a rental, or with public transportation. Or at least one can drive for 3-4 hours before stopping to charge. 100 miles sounds more like ‘stopping every hour to charge’.
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THINK – the Swedish company – has stated that they are going to be installing 10 minute rapid chargers. Haven’t seen anything after that initial announcement. If Level 3 charging can get under 30 minutes, 20 or less, I think there’s another psychological barrier which will fall.
Let me add. I see the 100/200 mile range issue a lot like pixel count for digital cameras was.
Around the year 2000 we had very good 2 megapixel digital cameras but some people stayed away from them because they wouldn’t make nice big high-detail prints like 35mm film.
Fact was, almost never did those people make large high-detail prints. They made small prints to pass around, emailed or posted their pictures on line, or when they made larger prints it was about content, not detail.
Once pixel counts moved up higher then people jumped in. And used high pixel count digital to make small prints, emailed or posted….
Thanks for adding in parentheses that these companies are privately held!
rkt9,
Perhaps you would agree that those interested in technology come to it for diverse reasons: some to learn, some to know what is current and some for investment. You might also gain a sense from other articles (click on my name above the article,) that I consistently try to research more than I will eventually write to better understand scope and relevance. I am also including a stock reference where known and a notation that a company is privately held when that fact is available. Companies that are privately held today may have a unique perspective on employment ( http://cleantechnica.com/2011/08/16/dreams-that-fly-great-uav-videos/ ) or may be the public offering of tomorrow. I hope you found this article and others rewarding.
Good. It may find much use as storage of power.