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Imara Corporation Launches; New Li-ion Battery Technology for High-Power Applications

A Ragone plot of Imara’s NMC cell compared to iron phosphate, Mn spinel and NMC-Mn blends from A123Systems, Sony, Sanyo and E-One. Click to enlarge. Source: Imara

Start-up Li-ion battery maker Imara Corporation (formerly known as Lion Cells) has officially launched. The company developed a combination of processing technique and unique materials science technology to manufacture high-power, long cycle-life cells and packs, with an initial focus on the portable tools and outdoor power equipment markets.

Imara’s technology is materials-agnostic; for the initial line of 18650 cells, it is using a lithiated nickel-manganese-cobalt (NMC) oxide cathode. The Imara 18650 NMC cells offer an energy density of 140 Wh/kg, according to Neil Maguire, Imara’s VP of business development. (Maguire came to Imara via Delphi and GM.)

We went with a pure NMC, which offers the highest energy density, about 40% higher than iron phosphate. The technique that Sony and Sanyo use is to blend [their NMC] with Manganese spinel to get the high rate capability. That results in a big sacrifice in cycle life. Our technology allows us to get the high rate without the blending of the spinel.

—Neil Maguire
Cycle life performance. Click to enlarge. Source: Imara

The process—about which Imara reveals few details—creates a cathode with very low impedance, stable cycle life and high current carrying capacity. The initial core technology, exclusively licensed from the Stanford Research Institute (SRI), was developed and funded in conjunction with the US Department of Energy as part of the Partnership for the Next Generation Vehicle (PNGV) initiative.

One of the approaches SRI explored with PNGV (and that was reviewed by the National Research Council in a series of reports on PNGV) was the use of a non-carbon anode material and a nonflammable solvent base for the electrolyte. While these features and the nearly 2 V less-negative anode potential reduced safety concerns, it was at the expense of reduced energy-density and power-density potential. Because larger amounts of active materials and larger electrode areas were required to achieve the same energy and power levels as more conventional lithium-ion batteries, the SRI technology would likely have higher production costs.

Imara is not using that specific technology (although it does have access to some of the non-flammable electrolyte IP, Maguire said), but is leveraging material preparation and electrode manufacturing techniques developed by SRI. The Imara cells do not require more (nor less) electrode material than comparable cells on the market, and there is no great cost penalty or savings in the manufacture of cells. The savings are in the dollars per delivered Watt hours, Maguire said.

Imara has demonstrated the technology across multiple lithium-ion chemistries. It is being scaled to high-volume production and will be shipping by the 4th quarter of 2009.

The automotive market. Imara would like to get into the automotive sector, but sees that as a multi-year process, and one that begins with a ramping up of production capability via the tools market (an approach also taken by A123Systems). Its strategy for packs is to work with companies such as Ricardo and Tier One system integrators, as well as directly with the OEMs.

The Imara technology is very suited for high-power applications in hybrids; it is not clear yet whether or not it offers an advantage for an optimized energy cell (e.g., for EVs or longer-range PHEVs).

The technology we have is very low impedance. That’s important in high power applications, but we’ve yet to be determine how much of a technology advantage it is for a pure energy cell. With our equipment, we can coat more material, adjust porosity, and control how thick I want the material crushed, or how porous [the material will be]. If very porous, we have lots of ability to move lithium ions. Crush it thin, there’s not as good rate capability. We can wind more material, we can create energy cells, but our real technology advantage is power. The hybrid market is a really good fit for our batteries.

—Neil Maguire

Imara plans to introduce a larger format cylindrical cell next; that cell might be a better fit for SLI batteries as well as some small hybrid packs.

Manufacturing. Imara, based in Menlo Park, CA, has a pilot manufacturing facility in its headquarters that can produce more than 1 million 18650 cells per year. (Moving to a 32650 format would cut that in half.) It currently, however, has the ability to produce cathode material sufficient for 8 million 18650 cells per year out of the building. The company plans to ship rolls of the cathode material to where its customers are. Imara is currently in discussion with contract manufacturers in Asia.

Longer term, Imara is looking to set up a greenfield manufacturing facility in the US.




A breakthrough is difficult to see here. Many others seem to have very similar performances.

More competition may help.

Imara is not (yet) on the list of the 14 USA National Alliance to build facilities to mass produce battery cells + materials.


Cycle performance of automotive batteries is very important as no one wants to swap batteries or replace them except Mr. Aggasi. This chemistry appears to perform well at 1000 cycles which would mean a five year life cycle if charged 200 days out of a year.

Combining with supercaps would further the cycle life - though we have yet ? to see a LDV production vehicle put this combo to use.

Carlos Fandango

Cost and cycle life are the key differentiators for hybrid automotive applications.

The designer must size up a pack to deliver the required power. He can compromise somewhat on energy and weight. Cycle life has a minimum pass requirement. Cost would be the deciding factor.

BEV's are a slightly different proposition.

The designer must size up a pack to deliver the required (range) energy. Weight is kind of an upper limit criteria. Power and cycle life are minimum pass criteria. Cost is again the deciding factor.


Some battery packs, like Altairnano's, are life cycle predominant. Ohers are power or energy density predominant.

Could PHEVs and BEVs be equipped with a combination of two different battery packs or modules to supply extended duration, fast accelleration and extended e-range?

Todays (and future) improved electronic battery management system could be used to keep both packs within their safe operation limits at all times while giving acceptable overall performances.

Carlos Fandango

Hi Harvey,

An interesting combo idea is:

1) 200Kg, 15KWh Altair pack providing up to 150KW power (plenty enough). It should survive the lifetime of the car and a 10 min fast charge will give you 60 miles range. It would be fixed in place, mid centered for good wt distribution.

2) 20Kg, 6KWh Electrovaya modules providing 25 miles of range extension with each pack. You can buy as many as you need I would put in 8 slots for up to 200 miles range. (4 slots front 4 back)

The Electrovaya modules could be swapped out at a station on really long trips. Most of the time they will re-charge at 0.5C overnight.

It needs some fairly sophisticated buck/boost power management. The Eltrovaya modules have to "trickle charge" the altair pack without taking a peak load. I'm sure it can be done.

If I can think of it, I'm sure somebody smarter than me has already evaluated the idea. Remember me if you see a cars with this configuration in 3 years time. Maybe I can claim some credit for the idea :)

Of course you could just stick in 400Kg of Fe Po's and get a similar result, without the 60 mile fast charge capability.


Carlos - you have built a car that will cost $100,000 without the chrome kick plates or surround sound options.


I could have sworn I posted on this.

They tried that combo already and it appears it totaly sucked. Duno the reasons tho cost was one of em.

I think the general plan is a compact high power lith battery and an apu. For most bevs I see them using cheaper low power bat chems and just making citycars as thats realy the main market for bevs.

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