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EnerDel to Market Automotive Li-Ion Battery by End of 2008

1C discharge of an LMO/LTO cell—the type EnerDel uses in its HEV packs—at 30°C. Click to enlarge.

EnerDel will bring its automotive Lithium-ion battery to market by the end of 2008, said Charles Gassenheimer, chairman of Ener1, Inc., in an interview on Fox Business News.

At the recent EVS-23 in Anaheim, Gassenheimer said that EnerDel was targeting the hybrid electric vehicle (HEV) market as its primary market, its “bread and butter”, followed by the electric vehicle market in Europe as number two, and then the nascent plug-in hybrid vehicle market as a potential third.

At EVS-23, EnerDel had highlighted its prototype Li-ion pack—which it had unveiled in October—in a Prius. The company expects to release third-party testing results on the battery’s performance in the Prius during the first quarter of 2008.

EnerDel currently is developing two different types of automotive lithium-ion batteries: high power batteries for HEV applications; and high energy batteries for full electric vehicle (EV) and plug-in hybrid electric (PHEV) applications. (Earlier post.)

EnerDel is designing its HEV Lithium Power System as a safe, small, light and high-power replacement for NiMH packs. EnerDel’s choice of active materials for the HEV cell is LiMn2O4 - spinel (LMO) for the cathode and Li4Ti5O12 (LTO) for the anode.

Power capability. Although the operational voltage of an LMO/LTO system is lower than most conventional lithium-ion chemistry systems, the choice of LTO as the anode material provides the LMO/LTO system with high power capability.

Furthermore, the LMO/LTO cell can achieve the high power capability over a wide range of depths of discharge (DOD), therefore providing a wide range of usable energy, according to Taison Tan, EnerDel’s R&D manager, in a paper presented at EVS-23.

For example, the EnerDel battery pack in the Prius—although designed with essentially the same power specs as the OEM pack (1.1 kWh for the EnerDel Li-ion vs. 1.2 kWh for the OEM NiMH pack)—operates in a DOD window from 90% to 10%, effectively doubling the usable energy available from the battery. The OEM NiMH pack operates within a much narrower charge window—approximately 80% to 40%.) Although EnerDel has not yet taken the system to dynamometer testing, it expects that making approximately twice the electric energy available will substantially benefit the fuel economy of the vehicle.

Low-temperature operation. The LMO/LTO combination does not suffer from the degradation in power or capacity at low temperature as do some other Li-ion chemistries. The capacity of the EnerDel cell achieved at -30°C is more than 90% of the capacity achieved at 30°C.

In addition, discharging at lower temperatures brings the risk of dendrite formation with other chemistries, which can lead to shorts. According to Tan, this is not risk with the LMO/LTO chemistry, since the nominal voltage of the LTO anode is approximately 1.5V—providing a potential that does not allow for the formation of lithium dendrites.

Long life. Both active materials are of spinel structures, providing high stability under charge and discharge. During the intercalation and de-intercalation of lithium ions, the LTO material experiences a volume change of approximately 0.2%, compared to graphite which experiences about a 9% volume change. Capacity in the cell remain flat for almost 3,000 cycles.

Design. EnerDel is using a prismatic design. The large surface area proves better heat dissipation, and allows for a variety of cooling options.

Specifications for EnerDel HEV LMO/LTO Cells
ParameterCD SizeA5 Size
Nominal Capacity 1.8 Ah 5 Ah
Nominal Voltage 2.5V 2.5V
Max Voltage 2.9V 2.9V
Min Voltage 1.6V 1.6V
Dimensions 145mm (W), 130mm (L), 5mm (T) 200mm (W), 111mm (L), 5.8mm (T)
Op. Temp. Range -30°C to +52°C
Storage Temp. Range -46°C to +66°C

EV Cells. In October, Think Global announced it had selected EnerDel as the supplier of choice for prismatic large format Li-ion batteries that will be used to power its Th!nk City electric vehicle.

On the Fox interview, Gassenheimer said that EnerDel batteries will be in the Think cars by the end of 2008. Under the supply agreement, EnerDel must deliver production prototypes in March 2008 and pre-production parts in July 2008. (Earlier post.)


  • Taison Tan, Hiroyuki Yumoto, Derrick Buck, Bob Fattig, Chad Hartzog (2007) “Development of Safe and High Power Batteries for HEV” (EVS-23)



price should be below 4500 Euro for a 10kwh pack

then i will buy a pluginhybrid with this battery

at the moemnt i make 100km a day, and i pay 4.5 eur in diesel


wow i really want this battery upgrade for my prius! if the price is really affordable since the absence of the inverters and the much larger battery pack. I can't wait for their test results in milage, there are COUNTLESS times that my battery fills up too quick and it had to cycle the engine to waste energy, what's worse under certain conditions the engine will consume fuel just to protect the battery!

Having the EV button helps, but there are still limtations, can't wait to see the published results.


Charles S

From an audio interview at ABG, the spokesperson said the 1.1 kwh pack costs about $1500.


How does one pronounce Li-Ion?
C'mon, let's use something pronouncable:
I suggest Lithion.


If I'm calculating this correctly, The prius battery gets 40% usable energy from the 1.2kwh battery or 480wh. So the range is 2 miles (@240 wh/mile). With the new battery we extend the energy to 880wh or 3.7 mile range for $1500. To get 37 mile range we will add $15,000 to the price of the car. Decent PHEVs will cost $30-50k. Will the mass market tolerate those high prices? 10 year old cars will become worthless making car ownership a relic of the past. PRT is the future


you have to understand that ev pure miles range is not the key here but rather than improving the MPG that the prius gets by doubling the capacity without adding weight. You could go and pay 9500 dollars and get a 15 mile of pure EV range (wiki a123 hymotion) off 4.3 KIlowatt/hr which translates to $633.33 per mile you get to drive in EV

$405.46 per mile is enerdel's cost, which sounds like a bargin to me if you don't have access to a plug but wish to lessen your pain at the pump, plus without the extra cost of inverters and electronics.


opps sorry 4.3 KILOwatt is the usable range of the a123/hymotion battery and is what 5kilowatt is what your paying for... which really shows what the enerdel is capable of if everyone bought their upgrade pack instead of hymotion.

the impact would be far greater because the cost is not as bad, now we just need to see the 08 results of the test and if the average mpg would be up lets say 10+ mpg? then who knows?

so 50 mpg prius would become 60 mpg prius? how long would it take to get 10 mpg back from $1500? do the math folks.


Don't LMO cathodes have trouble because the Mn dissolves and poisons the LTO? This isn't addressed

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