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NEC develops prototype 4.5V, long-life manganese Li-ion battery; 30% more energy density, high capacity and light weight

High voltage lithium-ion battery prototype. Click to enlarge.

NEC Corporation has developed a prototype next-generation manganese lithium-ion battery featuring cathodes that support higher voltage operations (4.5V rather than 3.8V) and an electrolyte solution that improves the stability of the higher voltage operations. These developments could help increase the range of electric vehicles in the future while reducing the weight of the batteries.

The new cathode and electrolyte solution improve battery energy density by approximately 30%, increase battery capacity and decrease battery weight, all while maintaining a high level of safety, based on the results of safety tests using a multilayer laminate-type cell. NEC presented the new cell at PRIME 2012, the Pacific Rim Meeting on Electrochemical and Solid-State Science, in Honolulu.

NEC currently develops and produces lithium-ion batteries with cathodes made with manganese. These technologies are used in large capacity storage batteries for electric vehicles as well as residential use. However, improving a battery’s energy density has been a challenging issue for further development. In order to solve this issue, NEC introduced higher voltage to batteries and made progress in the development of an electrolyte solution that suppresses the oxidative decomposition of the electrolyte solution that is generated on the surface of cathodes from the higher voltage.

These developments can contribute to increasing the driving range of electric vehicles, enabling the production of light weight storage systems and simplifying the management of battery systems by decreasing the number of cells. Furthermore, these new batteries provide high voltage drive and the same long operating life as conventional 4V lithium-ion batteries.

— Hidenori Shimawaki, General Manager, Smart Energy Research Laboratories, NEC Corporation

The new batteries are able to perform higher voltage operations as a result of using nickel in replacement of a material in existing spinel-structured manganese-based cathodes, which have a high level of safety while recharging.

The use of these cathodes and graphite anodes enables the average operating voltage to increase to a high voltage of 4.5V from the 3.8V of existing technologies. As a result, energy density increased by approximately 30% to 200 Wh/kg from 150 Wh/kg. This increases stored energy by approximately 30% when compared to existing batteries of the same weight. Alternatively, these new batteries are about 30% lighter when compared to existing batteries with the same energy storage.

To enable this, NEC changed the solvent of the electrolyte solution from a conventional carbonate-based solvent to a fluorinated solvent that is highly resistant to oxidation. This enables the suppression of oxidative decomposition where the electrolyte solution and the cathodes interface, which has posed a challenge for existing techniques.

These batteries maintain approximately 80% of their original capacity after undergoing tests with 500 full charge and discharge cycles in conditions below room temperature (20 °C), while maintaining roughly 60% when above room temperature (45 °C). Furthermore, the batteries demonstrate life span performance equivalent to that of conventional 4V batteries.

The practicality of these batteries are further demonstrated by the suppression of gas formation within cells and a significant reduction in the battery swelling ratio to 10% (more than 100% swelling in conventional batteries) after cycle tests conducted at above room temperature.

NEC says it will continue to drive research and development that supports greater capacity, life span and reliability for these batteries in preparation for their adoption by electric vehicles and large, stationary storage batteries alike.



A 30% gain in energy density plus superior all around performance may not be a major breakthrough but could be a major step towards future improved electrified vehicles.

The world needs a few more technology advancement steps like this one.


'These batteries maintain approximately 80% of their original capacity after undergoing tests with 500 full charge and discharge cycles in conditions below room temperature (20 °C), while maintaining roughly 60% when above room temperature (45 °C). Furthermore, the batteries demonstrate life span performance equivalent to that of conventional 4V batteries.'

And I thought the Leaf has lousy life time, especially in Arizona!
NEC can show them the way in duff battery chemistries.

Dave R

@Davemart - keep in mind that those test results are likely a result of 100% DOD cycles. Reducing the DOD should improve cycle life significantly.


I did.
It is still hopeless.


No matter what Davemart (and friends) says, battery technology is advancing at 8% to 10+% per year. By 2020/2022, 400+ Wh/Kg long lasting, quick charge, lower cost batteries will be on the horizon and moving in many electrified vehicles. Tesla S+ (and many others) will go 500+ miles per charge. The e-grids will not crash and the world will not have problems to produce more (cleaner) electricity for a very fast growing e-vehicle fleet.

Shortly thereafter, Davemart and friends will be driving (or pushing) their old technology ICEVs to the local museums (and cry all the way?).


Harvey D:
I have nothing against batteries.
Spouting technological optimism regardless of what the figures say on the specifics is as pointless as doomer depression.



like a battery powered toy maybe we should remove your own batteries to have you stop repeating the same thing over and over as if we were death or dump. It is getting really boring.

your are not the oracle of the battery industry and this site deserve better contributions than your immoderate fanatic views

Bob Wallace

Envia has developed a lithium-ion battery that holds over three times the energy storage of current EV batteries. 400 watt-hours per kilogram vs. 120 watt-hours per kilogram. This goal is already met and independently confirmed by the US Navy Naval Surface Warfare Center, Crane Division

Envia projects the cost at less than half the half cost of other EV batteries. $150 per kilowatt vs. $400 per kilowatt (apparent current cost). They can do this because they are boosting capacity over 3x so material cost per kg of battery doesn't rise appreciably.

The Leaf is getting a bit more than 3 miles per kWh. A 200 mile range EV would need approximately 65 kWh battery pack. Testing has shown >450 100% DoD cycles. That would make a 200 mile battery good for 90,000 miles before falling to 80% capacity.

At 90k miles there would be a choice of installing a new battery pack, continuing to use the vehicle with less range or selling it on to someone who wouldn't be bothered by less range. An EV with more than a 100 mile range would generally be an excellent second car or a great commuting car for someone looking to save money.

A new battery pack in order to get back to 200 miles for another 90k would cost $9750 plus something more for shipping/installation. And your used battery would have some residual value, perhaps half of the cost of a replacement.

Now, something wrong with my math or logic?

(Obviously Envia could be lying, but I'm not ready to believe that without some proof.)


BW...Envia may be a few years ahead in energy density and lower cost batteries. Others will most probably catch up with Envia and do even better by 2020 or so. The current 300 miles per charge Tesla Model S would become a 500+ miles per charge BEV?

This is not a dream (as Tree and friends would say) but common sense normal technology development and reality.

Post 2020 era or decade will be interesting for efficient (intelligent) electrified vehicle development, mass production and worldwide sales. It will not please everybody but the current trend cannot be stopped. Big Oil, Tar Sands, Shale, Corn Ethanol, Sugarcane Ethanol, Oil Refiners, ICEVs repair shops people and many others living from the old technology will have to adapt. ICEVs will have to go like typewriters, horse drawn buggies and many other technologies did.


Bob, it would be better to not to charge the battery fully every time, which really stresses most battery packs especially in hot weather. The batteries will last much longer if you limit the times you fully charge (or deplete) the battery to the occasions when you want the full 200 mile range. So, then the batteries should last much longer than 90,000 miles.

Oh yeah, any replacement batteries will have better specs for the buck than the originals.

Bob Wallace

Battery chargers are generally designed to slow the charging rate as the battery fills.

Rapid chargers/Level 3 chargers being installed along our highways are designed to give 90% charges and not 100% charges.

If EVs move to liquid cooling systems like the Volt uses then heat may not continue to be a problem.


I was deeply appreciative of the open way Envia participated in our discussions here.
What seems to be happening in the battery world in contrast to the 'ever onward and upward' meme is that that there are trade-offs necessary, rather than a generalised increase in all criteria.
In the case of the Envia 400Wh/kg chemistry, that was in power output.
That is fine if you want a really big pack, but even at their low price per kwh that is pricey

For me the most hopeful thing happening at the moment is plug in hybrids, and I am nearly as impressed with Ford's C-Max Energi with 20 miles of all electric range from a 7.5kwh pack (from memory) at a reasonable price as I was unimpressed by their Focus EV.

The ~100kwh pack we would need for anything like ICE performance does not seem to be swiftly getting nearer at other than very high cost.

Envia are certainly more impressive than this NEC press release though, as the battery they are describing does not seem to much improve any major criteria.
Panasonic already have better specific energy in production, that is what is going in the Tesla, and that seems to be what NEC are mainly boasting about on this one.


The problem is the lifespan is indeed shorter then other batteries being used right now. This means they would have to cut soc and that would cut into its one advantage.

Also to give you a clearer starker idea of the problem...

Just to increase range by a third and decrease pack size by a third and reduce cost by a third takes a pack that is more then twice as power dense and less then half the cost per kwh.... Now to get anyware they will need to do that twice....

Thomas Pedersen


How's this for a combination of series/parallel PHEV:

The electric motor and battery takes care of all driving and acceleration below, say 45-50 mph. At highway speed an ICE kicks on with only a clutch and a fixed gear ratio, but no gearbox!

The idea is to utilize that an ICE does not need to run at constant rpm to be efficient but can usually achieve >90% of its max efficiency at a wide range of rpm, e.g. from 1500 to 3000. This concept eleminates both the gearbox (parallel hybrid) and the generator (serial hybrid), both costly and heavy. And in the range from 45-85 mph the ICE has enough power to be charge sustaining and run at high efficiency. At higher speed its efficiency will drop, however this is of little practical importance.

The only drawback is that the car depends wholly on the battery for driving below the cut-in speed.

Any comments on this concept?


What about the military and security aspects in all of these new technologies improvements. If someone discover build and market a real breakthru powerful battery or a self rechargeable battery then it will change the power source of military equipments all over the world with bigger, badder power, so increase the danger of conflicts. A system with hydrogen self recirculation can theoritically replace all military power source and increase the power. I guess that military race prohibit real breakthru in car devellopment for security reasons and we actually are plague with obsolete, limp, costly and polluting car technologies build and marketed by gm, ford, chrysler, fiat, mercedes, bmw, volkwagen, audi, toyota, nissan, honda, mitshubishi, lexus, porsche, ferrari, john deere, caterpillar, white freightliner, detroit diesel, pratt and whitney, boeing, airbus, bic lighters, coleman camping equipments, suzuki, yamaha, bombardier, harley davidson, etc.

Bob Wallace

I fail to understand how better batteries would increase world hostilities.

Right now we are in the third of our wars for oil.

Can you explain how a war for batteries would get started?

Bob Wallace

Davemart - I need some help understanding battery technology.

Here's what you say about Envia -

"In the case of the Envia 400Wh/kg chemistry, that was in power output."

Here's what Envia says about their battery -

"Envia Systems, a technology leader in high-performance, low-cost lithium-ion energy storage solutions today announced test results that verify the company's next-generation rechargeable battery has achieved the highest recorded energy density of 400 Watt-hours/kilogram (Wh/kg) for a rechargeable lithium-ion cell."

When I look up energy density here's what I find -

"Energy density is the amount of energy stored in a given system or region of space per unit mass."

Now I'm operating pre-morning coffee and perhaps missing the obvious, but isn't energy density another way of saying capacity?


I think you mean not just capacity , but capacity for a given size (mass actually) - so yes, sort of.

but be sure you realize; "energy density is capacity per kilogram"


Bob Wallace

Half a cup underway, but it and that doesn't clear my thinking.

If Envia can produce 400 Wh/kg then they must be keeping size/mass roughly constant while increasing energy density/capacity. They're messing with cathodes and anodes while keeping the electrolyte the same.

A battery no larger or heavier than the 24 kWh battery of the Leaf but yielding 80 kWs. (A 240 mile range Leaf.)

Am I off track?

Bob Wallace

Those with deeper knowledge pools than I might want to read over this page on Envia. Perhaps they can spot the fatal flaw I can't.

I just found it and noticed that they are now reporting >1,000 100% DoD cycles. In a 200 mile range EV those would be 200,000 mile batteries. Forget replacement batteries.

Now we're talking a 200 mile range Leaf with 200k life-mile batteries for less than what the current Leaf costs.


Hi Bob:
As a non engineer it took me a while to get my head around the different terms!
The essential difference is between the total energy held by the battery, and how fast it can be released:
Specific energy: Energy per kg
Specific power:output per kg
Energy density: energy per litre
Energy power: output per litre

My understanding was that the chemistry Envia was promoting as high in energy density had low power and hence any car would need a big battery.
I would be very happy if they have overcome this.

Roger Pham

@Thomas Pedersen,
I've been discussing this type of serial/parallel transmission-less HEV concept here in GCC for many year, in relation with the release of the GM Volt. When the Volt was announced to be a purely serial hybrid, I criticized the Volt as being less efficient and less powerful than a serial/parallel hybrid in which the engine torque can be directly coupled to the drivetrain at cruise.

Bein both serial and parallel hybrid means that battery is not required at low speeds, because the engine will turn the generator which will then power the motor indirectly via electrical means. However, that means that you will have to accept losses in the generator and in the motor and in the power electronics. The efficiency will be from 70-85%, depending on load.

Now, then, since rated horsepower and acceleration performance is important to sell a car, if the engine power can be coupled to the drive train at lower speeds to add to the power of the electric motor driven by the battery, then you can easily double the hp output of the engine-motor-battery combination and bring the car into another category above economy class and command a much higher list price. The power combination of a serial/parallel PHEV can easily propel the vehicle into luxury class and transport the owner up into the statusphere!
For that, you will need a 2-3-speed transmission to double to quadruple the engine torque at lower speeds in order to create tire-smoking acceleration to please the motoring enthusiasts who are willing to shell out extra bucks for that type of thrill! You will also need a high power battery instead of a high-energy battery. The generator can also be turned into a motor for even higher rated hp. All-electric range is of secondary importance in comparison to performance.

A gear-change transmission is also important to reduce the size of the electric components for those more thrifty buyers who wants to buy only a minimum-cost hybrid instead of all-out performance. Compare the size of the electric components of the Huyndai Sonata hybrid to that of a Prius.


Specific energy density or battery energy density is usually expressed in Wh/Kg. Well designed light weight electrified vehicles can go as far as 10 Km per kWh but very few can actually do better than 7 Km/kWh

A 100 kWh battery @ 400 Wh/kg would weight about 250 kg (550 lbs). Using this battery @ 80% of its capacity, i.e at 80 kWh usable, it could power a (7 Km/kWh) electrified vehicle for about 560 Km (about 350 miles) and a (10 Km/kWh) electrified vehicle for 800 Km (about 500 miles).

In other words, a 100 kWh high energy density (400 Wh/Kg) battery could give 500 miles (800 Km) per charge to a well designed light weight EV and could meet the requirements of most drivers.


The problem as metioned by one person here is the POWER density as apposed to energy density.

Some high energy dense batteries are very low power density as in they cant discharge all that fast... The result is in fact the need for a much larger battery to provide a given power output.

So what is the POWER level of this battery?

Also typical batteries used in other cars have cycle lives of 3000 plus... so um ick....


It is my understanding that ENVIA can optimise their battery chemistry to suit the type of EV it will be used in. The 400 Wh/kg specific density version is conformed for a BEV with a reasonable sized battery. Conforming for a PHEV would result in a decline in Wh/kg but increase in W/kg, although not sure by how much.

I have yet see any energy density figures for the battery. Has anyone seen any data on this?

By the way the only data I have seen on cycle life is for 300 80% DOD. Looks good so far, but could start to to decline sharply at any point.

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