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

26 September 2012

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.

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.

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?

A D is the anti-HarveyD!

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.

"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?

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

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

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?

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.

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.

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.

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.

"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.)

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.

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.

AD, did it ever occur to you that hydrogen is far more flammable, and therefore dangerous than even the worst Lithium ion battery? BTW, did you know what causes the Li cells to burst into flames? The small amounts of metallic dust in the cell can cause resistance that can heat the oxygen and metal causing it to burn....which then in turn causes the cell next to it to burn etc etc....hmm....what gas is more flammable than oxygen?

ANyone?

Anyone?

Oh yes and what gas is harder to contain than all the other gases?

Anyone?

Anyone?

You guessed it. That's Hydrogen.

My point is not to mock Hindenberg er um, I mean AD but to merely point out that any high energy density system, including gasoline will have inherent risk. Manage the risk and it's viable.

Some trims of the Mitsubishi iMiEV cool the battery during charging:

'The custom-made battery pack on the ES trim of the Mitsubishi i is equipped with a fan-driven, forced-air induction system that automatically engages to protect the battery from overheating during charging. Drivers can upgrade to the Premium Package which allows, among other good things, the ability to charge the Mitsubishi i with a public quick-charger. Because quick-chargers can tend to heat batteries and reduce their efficiency in the long term, we've added an air-cooling system that draws cold air from the air conditioning unit to keep the battery nice and cool, even in hot climates.'

http://i.mitsubishicars.com/miev/charging/battery

Yes BW...a combined cabin/batteries temperature management system using a reliable, ultra high efficiency, High/Low Temp Heat Pump, should cost nor weight that much more than current cabin troublesome AC when mass produced with light materials.

A local USA firm is ready to mass such units.

Self-contained dual purpose heat pumps may become standard equipment for electrified vehicles in the near future. New rooftop laser type (70% efficient) solar panels could supply most of the energy for the temperature management system when it is most required...i.e on hot sunny days.

Batteries, motors and wiring all generate resistance heating, it's true but compared to an ICE heating management system, i's a walk in the park and if a clever engineer can heat exchange that with the cabin air, well you've got yourself a problem that becomes a solution!

If memory serves, EV1 had such a heat exchanger.

I am still not a fan of Lithium though. Thermal runaway is scary and Pb can take such a pounding. Has anyone heard of the lead foam concept? The company went bankrupt I think.

You're thinking of Firefly Energy, and yes they did liquidate IIRC (after losing out on a round of DOE project money).

I wonder about that lead-carbon stuff.  It should have been easy and cheap to make, ideal for PHEV use because of the high current capacity.  The use of carbon to replace the connective function of lead would have saved a lot of metal and made the battery far lighter.

"Self-contained dual purpose heat pumps may become standard equipment for electrified vehicles in the near future."

This makes huge sense to me. Keep batteries from overheating and warm them up in very cold times. Worst case, it would mean that EVs would need to be plugged in when parked in extreme temperature conditions, which would not take a lot of infrastructure.

Running conduit for future outlet installation should become part of building code for new construction. Some locales have already begun requiring conduit runs to parking spaces. Conduit is cheap and easy to run during construction. Then later all that is needed is to pull wire and connect both ends.

i THINK wireless induction heating would be a great feature of office parking complexes. You could pay the attendant to switch on space A-22 and your car woujld simply charge from the field upon which it is parked....and manage heat etc. If there was an issue of runaway or fire, the car should alarm to warn people/owners/attendants.

Just trigger it from your phone or computer. It should be a minor task to design a system that can ID the individual car and bill the owner for electricity used.

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