Altairnano's Cell Technology

Most Altairnano investors are familiar with the 2.5Ah cells that were tested a few years ago cycled at a rate of 10C charge (6 min.) and 10C discharge (6 min.).  And this was a constant current so it went from zero to 100, 100 to zero, zero to 100 and so on.  A cycle life of 25,000 cycles was observed.

Today Altairnano has 3 cells that they work with on a regular basis:  The 11Ah energy cell, the 50Ah energy cell, and the new 3.5Ah power cell.  All three are estimated to have, in general, a cycle life greater than 15,000 cycles and a calendar life exceeding 25 years.  The 3.5Ah power cell, at its 50C rate, will, however, probably be capable of something less than the full 15000 cycles and 25 years.  Also, if they run at a higher temperature or have a higher cycle rate then it also might be a little bit less.

Self Discharge

Primarily for stationary and military applications self-discharge can be important.  From a military standpoint, there may be applications where a battery may be shelved for a period of time perhaps into a warehouse, vehicles, or equipment.  Durable shelf life is a desirable facet in that, when, in a yearís time, the application is pulled back out for use the actual battery performance will still be able to start that application and run it.  At 25 degrees Celsius, beginning at 80% state of charge (SOC), there will be approximately 3 percent discharge of the actual unit per year.  Thatís not lost capacity but rather just a 3 percent loss of energy which can be recharged back up to 100%. Because temperatures are different all over, it has also been tested at 55 degrees Celsius to see less than 10% capacity loss over a yearís time.  (More on varied temperature tests later)

The 11Ah Energy Cell

The 11Ah energy cell has Specific Energy of 74wh/kg Specific Power of 1.1kW/kg, and a maximum charge rate of 10C.  In Transportation it can be used for auto EVs, auto PHEVs, Fleet PHEVs, and rail.  In Ancillary Services it can be used for grid regulation, large wind and for UPS, and in the Military it can be used for ship spinning reserve, ordinance power, and power conditioning.

The 11Ah cell is being tested at various C rates and temperatures.  At 6C charge/2C discharge rates, 100 cycles and 45 degrees Celsius (77 F) itís going very strong.  This test is on-going.  Another test has it at 55 degrees Celsius (131 F), over 6000 cycles and 1C discharge.  There about 87% percent of the initial capacity is still available.  This is in constant cycling and constant current and still on-going.

For the 11Ah cell at a 25 degrees Celsius 195 days of test it has experienced roughly .1 percent, exceptionally low, performance fade.  At 40 degrees Celsius (104 F) itís running at about a half of a percent, and at 55 degrees Celsius (131 F) itís up about 1 to 1.5 percent.

Different temperatures were chosen which make sense in the industry, 25 (77 F) is a base line and applications of 45 (113 F) and 55 degrees Celsius (131 F) are common in the transportation and stationary power applications.  Based on that information available to date, a couple of hundred days worth, it suggests that 25 years of life is not unreasonable with this technology.

The 11 Ah energy cells discharge rate capability yields over 90% discharge capacity in 6 minutes.  More than a 90% capacity retention at 10C (6 min) was observed.  The charge rate capability yields very similar performance.

Typical PHEV power requirements are about 400w/kg.  The 11Ah cell discharges from 1700w/kg down to around 750 w/kg.  At the low end of the discharge the cell is still not quite double these typical power requirements.  This vehicle can essentially run in EV mode for about 90 % of the capacity of the battery.

The performance of the 11Ah cell at -30 degrees Celsius (-22 F) is 50% retention at a 1C (1 hour) charge, 5C (12 minute) discharge rate.  There arenít many energy storage devices that can charge/discharge at this temperature.  ALTI has one application, going into production very soon, which has operating temperature requirements of -40 degrees Celsius (-40 F).  The electrolyte only just meets those requirements, but it does, so production will begin soon.

The 50Ah Energy Cell

The 50Ah energy cell has Specific Energy of 72wh/kg, Specific Power of 1.1kW/kg, and a maximum charge rate of 6C.  In Transportation it can be used for light and heavy HEV, transit PHEV, and rail.  In Ancillary Services it can be used for grid regulation, large wind, UPS, and spinning reserve.  In the Military, like the 11Ah cell, it can be used for ship spinning reserve, ordinance power, and power conditioning.

The 50 Ah test cell, at 25 degrees Celsius, was at about 6200 cycles and still running fairly well up above 90 percent at a rate of 2C. Testing is ongoing.

The round-trip efficiencies of the 50 Ah cell are notable.  One of Altairnano's applications  is at approximately 25 degrees Celsius and calls for fairly low C rates.  At C/5 the round-trip efficiencies are not quite 99 percent.  Theyíre good for undersea applications as well as the maintenance of electronics due to the efficiency of the battery - it lasts for a very long time within the application.  So if you have something thatís going down to the sea floor thatís going to run power electronics or something of that nature, itís very simple; You put the battery in and it has an exceptional life and very little concern.

The 3.5Ah Power Cell

ALTI had been working with, and testing, the 2.5Ah cell in the lab but now, in production, is moving it up to a 3.5Ah cell.  They just received their first batch of 3.5Ah production cells in late November 2008 and have begun running the same tests previously run on the 2.5Ah cell.  There are a couple of more months of testing to do and so far everything looks fine.

The new 3.5Ah power cell has Specific Energy of 40wh/kg, Specific Power of 4kW/kg, and a maximum charge rate of 50C.  In Transportation it can be used for light and heavy HEVs or large diesel starters, in Ancillary Services it can be used as a super capacitor alternative, and in the Military it can be used for weapons pulse power, HEVs, as an aircraft starter, and for communications.  In military applications the pulse power applications are exceptional.  It will give you 30 second pulse power runs versus what the industry normally recognizes as 10 second runs.  Itís much more energy dense from a normal super capacitor standpoint.  It has the power of a capacitor but has the energy to fulfill other requirements.  At -30 degrees Celsius it has 87 percent utilization at a 15C rate.

Gen II Cells

ALTI will have a second generation 11Ah cell that will be available in about Q4 09.  The performance is different due to a cathode change and the nature of the new Cathode. (LiNiCoMnO2).  The performance will differ in that the specific power will decrease from 2200w/kg to 1000w/kg so it will still be more than twice that minimum PHEV requirement of 400w/kg.  A benefit to this chemistry will be that the observed cell voltage (OCV) vs the SOC will be a very smooth curve.  This simplifies challenges for battery control systems on electric vehicles and makes them much easier to control. 

"Next generation cell design (will) Improve cell performance by increasing energy and power density"  - Annual General Meeting Presentation June 4, 2009

Hot Box Safety Test on the New 11Ah Cell

Gen II Cycling Test

June 25, 2010 - Altairnano Granted Patent for Nanotechnology Manufacturing Process

July 8, 2010 - A patent application was published for an Altairnano high power, low energy density cell using carbon coated electrodes. At the 80C rate (45 second) it has 2000W/kg with 1,000 cycles of life or a "full charge" of 49Wh/kg in only 3 minutes. According to the application it's good for power tools and digital cameras according to the application.

Altairnano Power Partner Page

Altairnano Investor Portal