Altair Nanotechnology's Battery: Faster, Cooler, More Efficient
by David McClellan - Jul 21st, 2008
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The advance of battery technology is getting a boost from a Reno-based company called Altairnano whose specialty is nanotechnology. The firm has developed a battery whose negative electrode -- the anode -- is made from nanoscale titanium.
The advantage? Less electrical resistance so the battery can handle higher current loads -- and less loss of energy to waste heat, which translates into greater efficiency.
The battery is being put to the test by a car company, a global power company and the US Navy for three separate applications, all of which save energy and reduce CO2 emissions: as the battery inside a plug-in electric vehicle, as a storage and grid regulation device to complement wind and solar energy and as a replacement for back-up diesel generators on warships.
It's worth keeping an eye on developments. Here's the latest.
Navy Tests Battery as Replacement for Backup Generators
The US Navy is running a test to replace the backup generators on warships, saving diesel fuel, CO2 emissions and a lot of taxpayer money. They hope to save $1.6 million in diesel per year for each ship. Multiply that by the 100 or more warships in the Navy fleet, and that’s a lot of diesel, money and CO2.
Warships keep a backup diesel generator running at all times. The reason is that even a momentary electric outage could be catastrophic to the operation of the electronic warfare systems. If the main generator goes down, a ship could be hit or sunk before a backup generator could start.
The trial of the Altair battery is using a 2.4 megawatt version. The testing was announced in last quarter’s conference call for investors, but they didn't divulge details of when it would begin or how long it would last. The Department of Defense and the Navy are well known for very long, extensive testing, so don’t expect any news for a while.
So it may be some time before your local battleship sports one of these, but ongoing results are sure to help technology development.
AES Grid Tests Finished
On July 8, Altairnano released the results of testing the battery for managing grid scale, real-time energy fluctuations in milliseconds. How good is the battery at regulating irregular power supply from wind and solar sources?
The higher current flow of Altair's battery is the key advantage here because it means the battery can respond quicker and with more power to smooth out larger grid swings than other batteries can. The testing was done by a third party tester, KEMA, for AES, an international power conglomerate with 123 power plants on five continents.
They tested two batteries, each rated at 1 gigawatt, 250 kilowatt-hour and 300 amp-hours. In one test, each battery was able to repeatedly charge or discharge 250 kilowatts in 15 minutes. That is, at a 1 megawatt per hour rate. They also tested something called frequency regulation. The battery was switched from charging to discharging every 4 seconds, continuously for several hours. A drop in wind speed can lead to a grid frequency drop and subsequent power problems, as it did in Texas last February.
The results? The battery can respond within 1 second to charge or discharge at any power level, including the full 1 megawatt power. Each battery is big, the size of a tractor-trailer and multiple units can be combined to scale up for more power.
Here's what Chris Shelton, Director of Energy Storage Development at AES, said of the results:
Fast-responding, high-efficiency energy storage systems such as these will create a more resilient grid and allow for increased use of variable generating sources such as wind and solar.
The KEMA report also noted the batteries can be used for ramp-rate regulation for solar and wind power and for critical peak-price response.
The measure of efficiency in batteries is called round-trip efficiency -- how much electricity you get back out versus how much you put in. If you were able to charge a battery with 100kW and then to discharge 50kW, the efficiency would be 50/100 or 50%. This is a critical feature for grid regulation because every kW lost to low efficiency is a kW the utility company can’t sell. And selling kW is how they make money. They don't want to see 10% of their inventory vanish any more than any other business would.
The efficiency for this battery was excellent at 91-97%, depending on the discharge rate. As is typical, the efficiency goes down a little when you discharge at the full 1 megawatt rate because electrical resistance goes up at higher current rates. For comparison, this is much better than the 65-70% round-trip efficiency for an NGK sodium sulfur battery that was tested last year for the same kinds of applications by Sandia National Laboratories.
Testing is hardly finished.
Like the Navy, power companies are also known for very careful extended tests. The point of these trials was to see if it was worth doing the next round of tests. And KEMA says the battery is now ready for pilot tests. In an earlier conference call, the CEO said that products might be announced and offered before the end of this calendar year without any details about what exactly those products would do.
Phoenix PEV Saga Continues
Phoenix Motorcars planned to sell 500 plug-in electric sport utility trucks (SUT) last year using Altairnano's battery. They even had 300 orders, but what they didn’t have was the money to build a production line.
Financing managed to arrive this year, so the new plan is to reach full production in 2009, with some vehicles delivered this year. They’ve also added a model they call an SUV to the lineup, though it looks more like a hatchback sedan. For now, they will only sell to fleet operators, most notably Pacific Gas & Electric. But you might be able to buy one in 2010.
Originally Phoenix had planned on using a 70kW battery, but this year’s models have been redesigned to use an 1100 pound 35kW battery pack. This gives them a range of 100 miles on one charge. The high current rate of the battery means the battery can recharge in 10 minutes, but that requires high current in the charging equipment, too, so you’ll need to use a 250kW charger, something you aren't going to be able to do from home. The high charging rate also comes into play when the battery is charged in the other typical EV way, from regenerative braking. Braking actually produces so much current that other batteries can’t use it all without overheating. The Altairnano battery can handle three times as much power, so it manages to save more of the current generated by braking.
The faster charging also means that filling stations for PEVs become far more practical. Drivers are unlikely to wait 30 minutes for a charge, but 10 minutes is quick enough to be realistic. The high power required for a fast charge would require some major infrastructure improvements: a station that offered 4 charging bays would need 1 megawatt. That's a power level characteristic of a neighborhood utility substation, not your local Texaco.
If the infrastructure can be worked out, it still might make more sense for every neighborhood parking spot and apartment dweller to get a parking meter style charger installed. Owners with garages will likely opt for wiring and chargers to have convenient, if slower, home off-peak charging.
The Altairnano battery has its drawbacks. The biggest is its density, which is a measure of energy stored per unit of mass or volume.
Put simply, Altair's batteries can’t hold as much charge as its competitors, which means shorter range for a PEV or shorter charge life for a cell phone or laptop.
There was also a potential overheating problem in the Generation 1 version of the battery used by Phoenix. That problem was discovered by Altairnano and resulted in a large warranty claim against Altairnano and a $10 million dollar write-off. Phoenix has been using the Generation 2 since late last year, and there has been no sign of the earlier problem.
There are a lot of competing battery manufacturers, and some of them, especially A123Systems, have hauled down more big deals. That said, developing batteries for the PEV market is going to be a marathon, not a sprint, so Altairnano's high current solution may still play a large role.
A Few More Nano Details
How does the Altairnano battery achieve higher current flow and run so efficiently? Well, the reason for both of these is the low resistance in the battery. Because resistance is low, higher current flows through the battery. And because of the low resistance, less energy is turned into heat and lost, so the efficiency is higher.
The next question is this: How did they get the resistance to be so much lower than other batteries? Conventional lithium ion batteries use a copper anode coated with graphite. When ions, the positively charged atoms that carry the electric charges, try to pass through the graphite, it meets high resistance because graphite isn’t very porous, and it is actually such a tight squeeze that the graphite has to deform.
Altairnano makes nano-particles of a lithium titanate oxide spinel (that’s a combination of lithium, titanium and oxygen in a particular crystalline structure ) and coats it on an aluminum anode. Because the coating is made of nano-sized particles, it has 100 times more surface area to offer the migrating ions. The larger pores in this coating also easily accommodate an ion without deforming.
Graphite coated anodes have another risk that Altairnano avoids. Engineers politely call it thermal runaway, but you could just as well call it a fire. If that graphite coating cracks for any reason, the battery can heat up and catch on fire. This is the exact problem that led to the massive laptop battery recalls in the last few years.
(Full disclosure: The author owns about $1,500 worth of stock in Altair.)
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Vaporware
This is all vaporware. Tiresome, tiresome vaporware.
Only GM?
Aren't there any other car companies interested here as well? Any entries from the Japanese manufacturers like Nissan? I'd love to try out this new battery and add it to my nissan part truck to make it an electric.
GM-Volt claims that it is
GM-Volt claims that it is enough 8 kWh per 40 miles. In that case it would be 160 miles range available from 35 kW battery pack. I would be satisfied without ICE range extention in case filling stations would be available on each 50 miles. My average long trip would last 3 hours and 20 min instead of 3 hours. This would be 11% longer than average with ICE. May be I will take lunch at petrol station. Good for restourant business. But on other hand I will save my time on city comuting when charging during night time and passing petrol stations during rush hours.
GM Volt comparison
The Phoenix Sport Utility Truck is no doubt a lot heavier than a Volt; they claim it can hold 4 adult utility workers and tools and still go 95 mph or so. Originally they planned on twice as much battery (70 KWh) and a range of about 150 mi instead of 100. I'd guess they'd redesigned it for 35KWh of battery instead to drop 1000 lbs or so of battery weight and maybe that let them make the frame lighter too. Anyway, the Volt numbers sound reasonable given the likely difference in weight.
Given the cost of the batteries ( $20-$35,000 for the 35 KWh battery pack - but it's really hard to know because Altairnano won't talk about it ) it might more sense to go for a 10 or 15 KWh pack for a 50 mile or 75 mile range. That range is likely to be the biggest marketing hurdle.
Maybe they should sell the batteries in 5 KWh increments so you can buy as much as needed for routine use. Then let you rent an extra 20 or 40 KWh pack for your long trips.
Grid Applications for Altairnano Batteries
I'm wondering why there's so little understanding of how batteries can help power producers. When they talk about frequency regulation, utilities refer to how the grid reacts to increases in demand - you can get brown-outs and/or frequency fluctuations.
Both are artifacts of having too little power available to respond to large increases in demand. (When there's too much generation, the excess is dissipated as heating of the transmission equipment.) Because the consequence of having too little power is low quality, to meet standards, producers generate a routine "excess" amount (~3%) calling it an "active reserve". Except when it is used to cover a sudden demand increase, this wasted generation is costs more than just the fuel used owing to the increased wear on power lines and substation equipment.
Substituting a battery for active reserve generation results in up to a 3% fuel saving. It appears that because the payback for using a battery to react to load variations will be measured in months and the life of a Nanosafe battery is measured in years, its adoption is an obvious money saver that, as fuel becomes more expensive, goes increasingly to the bottom line. Since money doesn't talk (it swears) I look forward to the wide adoption of this technology and the success of the Altair Nanotech enterprise. The decrease in emissions is a cherry on the sundae - a delight.
Roger, The editor added the
Roger, The editor added the SEM photo. Quite a stunner! If it happens to be of the Altairnano electrode, it would be quite a coincidence. There's a lot of merit in the idea of electric or hybrid buses, with trolley lines if necessary. Clearly not having trolley lines is the better way though. Here in Seattle we have electric/diesel buses with trolley lines. I lived along a diesel part of a bus route on a hill and was woken up many, many times as the driver gave it the gas. The electric part is a lot quieter, so I'm sure a lot of neighbors would go for your idea. A few years ago, Altairnano was involved in a trial for buses in China leading up to the Olympics. They did not win the competition and I don't know what happened after that. You might try to find out about that for more information on the general idea of an electric fast charge bus. I don't know how much charge it would take to move a bus, but if a 35kWh battery can move a 4,000 lb car 100 miles, it would seem powering a bus for a 10 mile route is in the ballpark. Even if it takes a 70 kWh battery, that's got to be a lot cheaper than diesel at $5/gal. Of course, buses do a lot of braking and must have the potential to generate a lot more current from that, so the high current battery is probably even more important here than it is for an auto. Given that, that battery range could be even better. As your web page points out, the wait at the end of a route before returning is frequently there to provide a margin of error so the bus can catch up to the schedule after falling behind. I expect the biggest cost for bus systems is the pay for the driver, so adding 10 minutes to the end of a run that doesn't already have a delay may be a cost problem. A battery that recharges in a time comparable to filling up with gas could be very important. It solves the problem of range, so now you don't even need the gasoline backup engine, which reduces cost and weight and adds range. It solves the problem of how to charge the car if you don't have a garage. Other solutions to both of these are possible, but a fast charge station would fit best into the way that people are used to doing business now. I don't have access to the full KEMA report. Maybe Altairnano would share it with you. They might be more willing to answer a very specific question, if you have one.
Fast charging has its place, but not not PHEV
First, where did you get that scanning electron microscope photo - is this of the Altair anode?
Second, as you mentioned, high power (fast charge, discharge) is where these batteries shine. I want to use these in urban buses, doing fast charging at the route ends - see nanobus.org for details. I think the Nanosafe would be perfect. What do you think?
Third, Plugin hybrids can charge slowly at night, they need high energy density, not high power, so other batteries may be better suited for PHEVs.
Fourth, Do you have the full KEMA report, not just the summary?
Roger
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