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Electrovaya launches next generation of MN series of Li-ion SuperPolymer cells; claims energy densities exceeding 200 Wh/g

Electrovaya Inc. launched the next generation of its SuperPolymer lithiated manganese oxide-based MN series of cells, first introduced in 2007 (earlier post), the “MN-HP Series”. The company says that the energy version of technology (MN-eHP) exceeds 200 Wh/kg—one of the highest energy densities for a commercial Li-ion cell in a large prismatic design, according to the company.

Electrovaya’s MN-HP series cells use commercially proven electrode materials such as graphite anodes and lithium metal mixed oxide cathodes. The company says that the MN-HP cells typically have 50-70% higher energy density than typical phosphate cells, and more than 120% higher energy density than lithium titanate cells.

Higher energy density cells require fewer materials for a given energy capacity and therefore can be produced at lower costs. Higher energy density cells also contain proportionately lower amounts of flammable electrolytes, which substantially improve safety considerations, the company says.

Typical MN-HP cells are available in 30Ah to 40Ah format (110 - 150Wh) and housed in a flat polymer pouch.

The cells are produced by Electrovaya’s proprietary non-toxic production process which does not use massive quantities of toxic n-methyl pyrrolidone (NMP), unlike most other commercial lithium-ion battery manufacturers.

Electrovaya’s proprietary SuperPolymer technology is independent of the composition of the positive electrode active material. As such, ongoing advances in positive electrode chemistry, such as the MN-Series, are expected to enable better technical performance and safety characteristics at more economical price-points, according to the company.

Electrovaya currently offers cells based on three chemistries:

  • The MN series (lithiated manganese material), which is the company’s recommended chemistry for transportation. Energy densities range from 170 to 210 Wh/kg with peak power up to 2000 W/kg.

  • Phosphate-Series, with energy densities from 110 to 140 Wh/kg.

  • Cobaltate-Series, for small cells only.

Cell capacities range from 2 Ah to 200 Ah.

Electrovaya provided the Li-ion battery packs for Chrysler’s test fleet of plug-in hybrid electric pickups and minivans. Last Friday, Chrysler announced it was withdrawing from service the test fleet of PHEVs for a battery-pack upgrade. Three of the fleet’s 109 pickups equipped with plug-in hybrid powertrains sustained damage when their prototype 12.9-kWh lithium-ion propulsion battery packs overheated. (Earlier post.) No announcements as to new chemistry or supplier have been made yet.

Comments

A D

These batteries are unable to power a small truck and also they are unable to power a small car for short distance without degrading themself. These batteries can only be use as a small electric buffer for fuelcell cars only to regulate the power and recapture some kw when breaking.

Bob Wallace

Where do you find those facts, AD?

It looks like they will need an active cooling system in order to avoid overheating. But did you find something that speaks to low cycle lifetime?

Engineer-Poet

A D is the anti-HarveyD!

Davemart

Hmm, let's see.
A similar chemistry to the one with a lousy cycle life in the Leaf, and just discontinued in the Chevy Spark due to fires.

Bob Wallace

"Higher energy density cells also contain proportionately lower amounts of flammable electrolytes, which substantially improve safety considerations, the company says."

Now, please refresh my memory. Do I not recall that gasoline is flammable? Perhaps it no longer is as seeing how some folks have their bloomers in a bunch over battery electrolytes being flammable.

If gas is, in fact, still flammable and we can carry 12 to 15 gallons around in our ICEVs how many gallons of electrolyte might be found in an EV?

And since we know that all the gasoline in a ruptured tank can burn how do we compare that to something like the BYD fire in which only the ruptured batteries burned?

Bob Wallace

Looking for some more info on the Chrysler battery issue I found...

"The pilot test fleet is comprised of 109 pickup trucks and 23 minivans. The company produced the batteries without using the NMP solvent used in most battery-manufacturing processes.

No one was injured when the batteries overheated. All indications seems to point to overheating while charging or when the vehicles were plugged in."

http://www.hybridcars.com/news/chrysler-changes-battery-direction-pilot-truck-minivan-phev-project-52532.html

Davemart

Bob:
You are in the right of it.
I should have said 'overheating' not fires.

Dave R

What are the odds that Electrovaya comes out with a new announcement the same day that Chrysler announced that they'd be replacing all the packs in their pilot PHEV fleet which was sourced with Electrovaya cells?

The big question is - what cells will Chrysler be using in the replacement pack and was the overheating caused by defective cells or BMS or packaging issues?

HarveyD

Thank you E-P.....I prefer to stay on the optimistic side even when a few manufacturers have thermal management problems with their new batteries. Overheating problems can and should be fully addressed before electrified vehicles are sold.

My 7+ years old (custom built) desktop PC uses 10 variable speed very low noise high quality fans. It never overheated nor had a failure. Internal temperature is continuously measured in 5 critical places and are always within +/- 2.5C. I also change the air filters regularly. The hard disks seems to vary a bit more than the other components but stay below 40C. It cost a few more $$ but it has worked extremely well.

Bob Wallace

Something more -

Sounds like the heating problems were only during charging, especially rapid charging.

A stronger cooling system might solve the problem. Using a bit more electricity during the charge process would lower the overall efficiency of the vehicle but it wouldn't lower the vehicle range since the power for the extra cooling would come from the grid and not batteries.

If someone was doing their normal night ~30 mile recovery charging at home then the charger could shut down when battery temps hit a set point and turn back on when they've cooled. Extra cooling should be needed only when pumping a lot of power into the batteries in a short time period.

---

"(M)ore than 120% higher energy density"?

Using some grid power for battery cooling while charging would be a small price to pay for a 200 mile range EV. Get us to a 200 mile range and we've cracked the "drive all day" nut. 500+ miles with only two ~20 minute stops.

Engineer-Poet

It might not be possible to balance the cooling properly while fast-charging.  Battery voltages decrease with increasing temperature; in a series-parallel connected string, an overheated cell will have less output during discharge (thus staying cooler) but GREATER charge rate during charge (making itself even hotter).  The only way to fix this is to reduce the charging rate.

HarveyD

Technology advancement will soon solve battery overheating problem during very fast charge/discharge. Until then, improved thermal management will have to be used. The technologies already exist.

Built in passive + improved liquid cooling may be required, specially during very fast charge/discharge periods and extended harsh use in very hot places.

Bob Wallace

"It might not be possible to balance the cooling properly while fast-charging."

Possibly. But consider a nicely integrated battery/cabin heat pump system. Give the battery pack plenty of cooling coils and make the heat pump robust enough to dump that heat into the atmosphere during charging. Circulate the coolant faster and use a lareger fan system to move heat away from the system while plugged in.

Use the heat pump to pull heat from batteries to cabin in cold weather.

We don't have information about how bad the overheating problem is. All we know is that it seems to be more than what the Chrysler test cars are capable of dealing with.

Let's take it further. Let's say that this is the best bettery that will ever be invented. We're stuck with this one. Could we make it work?

How about an electric plug and a coolant connection at rapid charge stations? Set up a robust cooling system outside the vehicle and let the heat be pumped outside the battery pack quickly during rapid charges.

(I don't think we'll need to go that route, but I just dislike the "Oops, that didn't work, let's give up" attitiude that is so popular these days. I'm a "let's-fix-this" engineer at heart.)

Engineer-Poet

Such fixes co$t, though, and the expense of the battery packs is already a sticking point.  At some point you have to set a price and build something.

Bob Wallace

I suspect that's why Chrysler moved to a different battery. They're already behind and designing a cooling system would have slowed them down even more.

If this battery has solved the weight/size/capacity problem and more than doubles range for the same size battery and without increasing material costs then a dual use heat pump should not be a budget buster.

Manufacturers are already looking to heat pumps for cabin conditioning. Using battery heat as opposed to ambient temperature air to warm the cabin would be a real energy/mileage saver. All that would seem to be needed would be a set of cooling coils in the battery pack.

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