## Axion Providing Lead-Acid Ultracapacitor Hybrid Batteries for Demonstration Projects With the US Army and Penn State University

##### 21 February 2008
 Ragone plot of the PbC (e3 Supercell) and other storage technologies. Click to enlarge.

Axion Power International, Inc. is providing “PbC Ultracapacitors” (PbC)—multi-celled asymmetrically supercapacitive lead-acid-carbon hybrid batteries—to the Applied Research Laboratory at Penn State University for testing in conjunction with the US Army’s Tank and Automobile Command (TACOM). The PbC is a hybrid device that uses the standard lead acid battery positive electrode and a supercapacitor negative electrode that is made of activated carbon. (Earlier post.)

The TACOM project will cover a broad range of established and emerging military vehicle applications including starting, lighting and ignition systems (SLI) for diesel engines that operate in extreme weather conditions; hybrid electric vehicle drive systems; silent watch systems; and other military applications where the lighter weight, higher power, and longer cycle-life of Axion’s PbC Ultracapacitors will improve the performance of existing systems and facilitate the roll out of new systems.

Testing is beginning immediately with the shipment of several different versions of PbC Ultracapacitors to the Applied Research Laboratory at Penn State.

PbC batteries use five-layer carbon assemblies to replace the simple sponge lead plate negative electrodes used by most other lead-acid battery manufacturers. The Axion assembly consists of a carbon electrode, a corrosion barrier, a current collector, a second corrosion barrier and a second carbon electrode. These electrode assemblies are then sandwiched together with conventional separators and positive electrodes to make the battery, which is filled with an acid electrolyte, sealed and connected in series to the other cells.

During charge and discharge, the positive electrode undergoes the same common half reaction based on the double sulphate theory for lead acid batteries—i.e. lead dioxide reacts with acid and sulphate ions to form lead sulphate and water.

Positive electrode: PbO2 + 4H+ + SO42- + 2e- ⇌ PbSO4 + 2H2O (+1.685 V)

However, instead of having a lead electrode that reacts with sulphate to form lead sulphate, the activated carbon electrode in the PbC is a very high surface area material that acts to adsorb and desorb protons (H+) ions in solution.

nC6x-(H+)x ⇌ nC6(x-2)-.(H+)x-2 + 2H+ + 2e- (discharged)

In conventional lead acid batteries, the concentration of acid changes from being very concentrated in the charged state to somewhat dilute in the discharged state as the acid is converted to water. In contrast, the PbC stores the protons in the negative electrode in the fully charged state which move to the positive electrode during discharge where they are neutralized to form water. The result is reduced acid concentration swings from the charged to discharged state which reduces grid corrosion on the positive electrode and leads to longer cycle life of the positive electrode, according to Axion.

The resulting device offers energy storage approaching lead-acid batteries, coupled with far longer cycle-life and power output approaching ultracapacitors. These low-cost devices recharge rapidly and use 40% less lead. During internal testing, prototypes have withstood more than 1,600 deep discharge cycles (charge-discharge every 7 hours to a 90% depth of discharge). In comparison, most lead-acid batteries designed for deep discharge applications can only survive 300 to 500 cycles under these operating conditions, according to Axion.

Axion PbC Price Performance Characteristics
ChemistryEnergy DensityUseful lifeCost of ownership per kWh
Wh/kgWh/LCyclesCapacityPer cycle
PbC 20.5 40 1,450 $610$0.42
Lead-acid 25 75 400 $250$0.63
NiMH 45 80 600 $900$1.50

The current PbC energy densities have improved from earlier versions of the technology, which Axion called the e3 Supercell. (Earlier post.) Axion is positioning its PbC technology as offering a balance between price, energy and power that is well suited to a variety of existing and emerging energy storage applications.

Axion has been producing prototype PbC Ultracapacitors at its lead-acid battery plant in New Castle, Pennsylvania for more than a year using the same cases, positive electrodes, separators, electrolytes and manufacturing equipment used in its other lead-acid battery lines. The only notable manufacturing difference is the use of Axion’s proprietary carbon electrode assemblies instead of lead-based negative electrodes.

In addition to Axion’s efforts to develop PbC Ultracapacitor solutions to existing and emerging military applications, Axion has begun work on a complementary project to replace the nickel metal hydride battery systems in a pair of Honda Civic hybrids with a less expensive and comparably sized PbC alternative. Testing protocols are being finalized with Penn State and will include data from upwards of 100,000 miles of road tests. In the second phase of the hybrid project, Axion will add Toyota Prius and other vehicles to the test regime.

Interesting that they didn't put modern L-ion batterys on their technology comparison charts. I guess they probably don't fare so well against those.

Under those deep cycles cobalt lipos may not fare so well, perhaps 300-500 cycles.. A123 LIFE cells have a been tested at 2000 deep cycles until they reach 80% capacity.. and A123 claims 15000 cycles for some of their new automotive cells, A123 cells have around 2-4 times the energy density of nimh cells, and just as safe.

The advantage of these batteries may be the low cost, similar to the usual lead-acid battery.. lots of applications for those that I can think off.

Firefly Energy's carbon-foam electrode can reduce lead requirements by 70%.  This scheme appears compatible, and completely eliminates lead from one electrode.

A vehicle system could combine the Axion batacitor (with or without the Firefly electrode) with Firefly 3D² cells.  The batacitor could provide surge power while a Firefly battery provides steady power.

When will technology like this move out of the lab, and into my car? I get tired of reading about tech I can't have. We're just not moving fast enough.

I want to know how this compares to EEStor's technology......it sounds like EEStor will dominate the energy storage market as soon as they start production of their ultracapacitors......

eji

EEstor is very unlikely to deliver what they claim, they simply neglect the dielectric saturation effect in TitanateBarrium under high field and they will be 2 order of magnitude below what they target. At best a 0.5KWh supercapacitor weighting 25Kg that can be used on HEV.

Asides I am not sure I understand the advantage of Axion Pbc. A firely with a supercacitor in parallel will return a much better power density with the same peak power at this one. But anyway it is good to see so much research going on on battery these days when thee progresses have been so slow during the 30 past years

The $/kWh per cycle is useful for comparing batteries with difference cycle life. Yesterday Ric Fulop from A123Systems projected$500/kWh for their batteries meaning they sell them for more right now but that they can sell them for $500/kWh if they got a volume order such as the Volt that takes 60000*16 = 960000 kWh at the first year of production. The A123 website show that their battery can do 3650 cycles before degrading to 85% of their original capacity. So A123 the relevant per cycle price is 500/3650 =$0.137 /kWh per cycle compared to Axion’s $0.42. Not only is A123’s battery much cheaper in this way it is also many times more useful because of its energy density of 115 Wh /kg compared to Axion’s 20.5 Wh/kg. As soon as A123, Valence, BYD and others get into volume production (>1 million kWh per year) of their nanotech batteries they will wipe out competitors with other chemistries even the lead acid producers. Their products are simply disruptive. I don’t even believe Firefly can compete. I have not seen their price and specifications yet but I doubt it can beat$0.137 /kWh per cycle and certainly not 115 Wh /kg. Maybe EESTOR has something that can compete but that is still a big secret.

It is going to be very interesting to follow how fast they can increase production to actually make a difference in the real world and to follow how low the price can go and how much higher future battery versions will go in terms of Wh /kg for this type of safe and durable batteries.

"EEstor is very unlikely to deliver what they claim, they simply neglect the dielectric saturation effect in TitanateBarrium under high field"

EEstor's reaction to that is that it is not simply a capacitor, but also a "battacitor", using integral lithium-ion chemistry along with the capacitor component. How that all works together... I've no idea.

@ Clett -

that approach is also known as a pseudocapacitor or electrochemical capacitors. In some chemistries, chemical reactions take place at just one electrode, while the other acts only electrostatically. In others, both electrodes exhibit a combination of electrostatic and electrochemical behavior.

Either way, the aim is to produce a device with capacity and power characteristics in-between those of a battery and those of ultracapacitors. The trick is getting the best of both worlds, rather than the worst.

http://www.nesscap.com/products_pseudocapacitor.htm
http://www.evanscap.com/isdlc5-2.htm

Dear sir, 12.5.08

I am interested in supercapactor application.Please send me the specification and Technical literature of your product.

with regards

Hi

Who has the data to generate the ragone plot, its nice I'd like to a the advanced PbA data for comparision.

Thanks

Henrik, you are absolutely right about Lithium being a game changer, but your analysis lacks depth. A123 is a pre-IPO company trying to generate buzz. Today there is no way they could build their capacitors at $500 per KWh. This is not a question of volume and mass production, it is a question of battery technology, manufacturing processes and equipment which doesn't exist today. Maybe two or three generations from now with high volumes they will be able to meet these lofty goals, but not for another couple of years. So lets reset that cost back to$800 per KWh.

Axion is a company just out of Chapter 11 which is also trying to generate buzz. They are trying to get the stock market to forecast their sales and profits based on their cost basis. So $610/KWh is a number they believe the market will allow. In reality, their cost is less than$250/KWh since carbon costs less than lead. So lets drop their cost down to $250/KWh. Now if you do the math Axion is at$0.17/KWh/cycle while A123 is at $0.22/KWh/cycle. Sure, Axion is not making the great profits they are predicting, but those profits are projected. The key difference between PbC and Li-ion is that PbC is a LOT cheaper to get into. Which do you think will sell better? A car which costs$10,000 or the same car which has a slightly lower per cycle battery cost which will cost $15,000. Obviously PbC wins. Another key advantage of Axion over A123 is that Axion technology can be integrated at nearly ALL present lead acid factories in the USA. A123 needs specialized factories which they are setting up way over in China and will have limited capacity. A123 can not ship enough batteries to satisfy their existing power tool companies, let alone electric vehicle customers. This is the problem with pre-revenue public companies. You really have to be an industry expert to analyze what they are saying. In their other press releases they say "Axion believes it will be able to sell carbon electrode assemblies as virtual plug and play replacements for the lead based negative electrodes used by all other battery manufacturers." The only way they will be able to do this is if their carbon electrodes cost about the same as the lead electrodes, which means the$610 is just there for shallow Wall St. pink sheet investors who don't understand the underlying economics.

And as for EESTOR, they are a complete scam, coupled together with another ethically questionable Toronto public company. You almost sounded competent until you mentioned EESTOR.

Henrik, you are absolutely right about Lithium being a game changer, but your analysis lacks depth. A123 is a pre-IPO company trying to generate buzz. Today there is no way they could build their capacitors at $500 per KWh. This is not a question of volume and mass production, it is a question of battery technology, manufacturing processes and equipment which doesn't exist today. Maybe two or three generations from now with high volumes they will be able to meet these lofty goals, but not for another couple of years. So lets reset that cost back to$800 per KWh.

Axion is a company just out of Chapter 11 which is also trying to generate buzz. They are trying to get the stock market to forecast their sales and profits based on their cost basis. So $610/KWh is a number they believe the market will allow. In reality, their cost is less than$250/KWh since carbon costs less than lead. So lets drop their cost down to $250/KWh. Now if you do the math Axion is at$0.17/KWh/cycle while A123 is at $0.22/KWh/cycle. Sure, Axion is not making the great profits they are predicting, but those profits are projected. The key difference between PbC and Li-ion is that PbC is a LOT cheaper to get into. Which do you think will sell better? A car which costs$20,000 or the same car which has a slightly lower per cycle battery cost which will cost $30,000. Obviously PbC wins. Another key advantage of Axion over A123 is that Axion technology can be integrated at nearly ALL present lead acid factories in the USA. A123 needs specialized factories which they are setting up way over in China and will have limited capacity. A123 can not ship enough batteries to satisfy their existing power tool companies, let alone electric vehicle customers. This is the problem with pre-revenue public companies. You really have to be an industry expert to analyze what they are saying. In their other press releases they say "Axion believes it will be able to sell carbon electrode assemblies as virtual plug and play replacements for the lead based negative electrodes used by all other battery manufacturers." The only way they will be able to do this is if their carbon electrodes cost about the same as the lead electrodes, which means the$610 is just there for shallow Wall St. pink sheet investors who don't understand the underlying economics.

And as for EESTOR, they are a complete scam, coupled together with another ethically questionable Toronto public company. You almost sounded competent until you mentioned EESTOR.

The problem with Axion is that their batteries have LOWER energy density than traditional lead acid meaning they end up being even heavier than lead acid. They will find it difficult to achieve customer wins if they are heavier than lead! Their second problem is they are substantially BIGGER than lead acid batteries from an energy density standpoint. This means you can't just replace lead with carbon as they advocate in their press releases because the resulting batteries will have less power.

It seems that they have stopped comparing themselves to Lithium Ion as they did in their previous press releases:

We will have to see whether they are able to secure the $10 Million in financing they were looking for from Quercus Trust but from the outside I don't see a very bright future for this company, which is probably why they entered Chapter 11 in the first place. The problem with Axion is that their batteries have LOWER energy density than traditional lead acid meaning they end up being even heavier than lead acid. They will find it difficult to achieve customer wins if they are heavier than lead! Their second problem is they are substantially BIGGER than lead acid batteries from an energy density standpoint. This means you can't just replace lead with carbon as they advocate in their press releases because the resulting batteries will have less power. It seems that they have stopped comparing themselves to Lithium Ion as they did in their previous press releases: http://thefraserdomain.typepad.com/energy/2006/02/axion_to_begin_.html We will have to see whether they are able to secure the$10 Million in financing they were looking for from Quercus Trust but from the outside I don't see a very bright future for this company, which is probably why they entered Chapter 11 in the first place.

Axion have recieved the funding from quercus so they must have sold their technology to someone, I cant remember what the stipulation was but i thought the only way they would get this money is if they made a major sale.

Thanks for information

Remember: Any Lead technology is self destructed, usually within three years!!!!!!!!!!!!!!!!!!!!!!!
Go cheap, you limit yourself !!!!!!!!!!!!!!!!!!!!