A123 Systems introduces new Nanophosphate EXT Li-ion battery technology with optimized performance in extreme temperatures; OEM micro-hybrid program due next year

Cold cranking performance of EXT battery systems, 80 Ah and 60 Ah. 10 sec. crank, 7.0V minimum, 100% SOC. The dots represent the capability of Johnson Control’s current AGM battery at that temperature point. Click to enlarge.

A123 Systems introduced Nanophosphate EXT (EXtreme Temperature), a new lithium-ion battery technology capable of operating at extreme temperatures without requiring thermal management. Nanophosphate EXT is designed to significantly reduce or eliminate the need for heating or cooling systems, while maintaining long cycle life at extreme high temperatures and delivering high power at extreme low temperatures.
“The primary transportation application where this is noteworthy is in the micro-hybrid space,” said Jeff Kessen, A123’s director of global marketing for the Automotive Solutions group. “We feel that we have erased the cold cranking deficit—the Achilles heel [for Li-ion] from a performance perspective against lead acid.” EXT batteries will go into production next year on a mainstream micro-hybrid system, Kessen said, although the customer is not talking about the program yet. The EXT battery is most of the way through product validation, he said.

EXT cycle life. Click to enlarge.

According to testing performed to date at the Ohio State University’s Center for Automotive Research (CAR) and the very low observed rate of aging, cells built with A123’s Nanophosphate EXT are expected to be capable of retaining more than 90% of initial capacity after 2,000 full charge-discharge cycles at 45 C. CAR has also starting testing the cold temperature performance of Nanophosphate EXT, which A123 expects will deliver a 20% increase in power at temperatures as low as -30 °C.
Nanophosphate EXT extends the core attributes of A123’s proprietary lithium iron phosphate battery technology—high power, long cycle life, increased usable energy and excellent safety—over a wider temperature range, enabling customers to deploy more advanced solutions that increase performance in applications that frequently experience battery cycling at extreme temperatures.
Because Nanophosphate EXT is designed to reduce or eliminate the need for costly thermal management, it is expected to deliver these performance advantages while also increasing reliability, minimizing complexity and reducing total cost of ownership (TCO) over the life of the battery system for a number of applications, including those within the transportation and telecommunications industries.

Based on our analysis, the performance of A123’s new Nanophosphate EXT at high temperatures is unlike anything we’ve ever seen from lead acid, lithium ion or any other battery technology. Nanophosphate EXT maintains impressive cycle life even at extreme high temperatures without sacrificing storage or energy capabilities, especially as compared with the competitive leading lithium ion technology that we used on our head-to-head testing. If our testing also validates the low-temperature power capabilities that A123’s data is showing, we believe Nanophosphate EXT a game-changing battery breakthrough for the electrification of transportation, including the emerging micro-hybrid vehicle segment.

—Dr. Yann Guezennec, senior fellow at CAR and professor of mechanical engineering at the OSU

The EXT technology incorporates changes in the active materials, electrolyte and a change in the separator, said Jeff Kessen, A123’s director of global marketing for the Automotive Solutions group.

Each of them [reflect] relatively subtle changes, not a revolution in materials. It’s the interplay of all the different elements. They are close derivatives of what we have in production today. We are still using a nano-based lithium phosphate material—the cathode material is not fundamentally different. We have the same safety advantages as before. We’re making it on the same equipment, so we don’t incur any significant capital costs. I’d characterize the chemistry as fine tuning.

—Jeff Kessen

Existing chargers and battery management systems designed for the original Nanophosphate batteries will work with Nanophosphate EXT systems.
A123 has identified two key high-volume markets for the EXT technology, Kessen said: micro-hybrids (i.e., start-stop) and telecommunications, especially in developing countries.

TCO calculations for a micro-hybrid application. The longer life and increased fuel economy yield a benefit to the EXT Li-ion batteries, according to A123’s calculations. While cycle life data shows at least a 4x advantage to Li-ion in terms of cycle life, A123 us only taking credit for 2x in this TCO analysis. Click to enlarge.

Transportation and micro-hybrid applications. By enabling increased power at low temperatures, Nanophosphate EXT is expected to substantially improve the cold-cranking capabilities of A123’s lithium ion 12V Engine Start battery. (Earlier post.) This eliminates what has historically been the only performance advantage of lead acid in starter battery applications, and A123 expects it to considerably increase the value proposition of the Engine Start battery as a lighter-weight, longer-lasting alternative to absorbent glass mat (AGM) and other lead acid batteries. According to Lux Research, the worldwide market for micro-hybrids (start-stop) is projected to reach more than 39 million vehicles in 2017, creating a $6.9-billion market for energy storage devices.
At its Analysts’ Day in 2011, battery market leader Johnson Controls noted that Li-ion performance was better than that of lead-acid for start-stop applications—at least from the point of view of cycle life, charge acceptance, and usable energy. The major downfall for Li-ion was cold-cranking capability and cost.
EXT addresses cold cranking, and in addition, can reduce total cost of ownership (TCO) for micro-hybrid applications. Although the initial EXT cost is higher, Kessen acknowledges, the nominal AGM life in a stop-start application is only about 4 years—i.e., the battery will need to be replaced sooner than an EXT battery. In addition, the fuel economy savings from the Li-ion system are higher, due to the the capability for increased charge acceptance.

Lead acid has a limited charge acceptance capability, especially for pulse charge; the ability to take a dynamic charge erodes quickly. After 6 months of field use, it’s down to a fraction.

Li-ion starts at a higher point and doesn’t degrade much. If you optimize the vehicle design around that capability, be more aggressive, put stronger alternator on car, if you do that, you can achieve a lot more energy capture and then use that energy by sustaining some of the electric loads in vehicle. Our customers are telling us an incremental 4-5% fuel economy gain because of greater regen energy capture.Jeff Kessen

In addition, Nanophosphate EXT could enable automakers to reduce or completely eliminate active cooling systems in electric vehicle battery packs. A123 expects this to lower cost, reduce weight and improve reliability.
Kessen says that the EXT capabilities could conceivably enable a switch from liquid cooling to air cooling, thereby taking a lot of components out of the vehicle—depending on duty cycle and the size of the battery in comparison to the power of the motor.
Telecommunications. Nanophosphate EXT supplements the advantages of A123’s lithium ion battery solutions for telecommunications backup, which are designed to replace the lead acid batteries deployed at new and existing global cell tower sites built off-grid or in regions with unstable power. These sites typically require diesel generators to support the batteries, and due to the lengthy charge time necessary for lead acid batteries, the generators are often forced to operate for extended periods.
In contrast, A123’s solutions charge about six times more quickly than lead acid, which significantly reduces generator run time and lowers fuel costs by 30% or more. At cell towers in extreme temperature environments, Nanophosphate EXT further reduces operating and maintenance costs by minimizing or eliminating the need for air conditioning or heating. In higher-temperature climates, for example, the cost of installing and running the air conditioning necessary to properly cool the lead acid batteries can represent up to 50% of the total power consumed at each cell tower site.
A123 believes that Nanophosphate EXT has the potential to significantly expand the global addressable market for its telecommunications backup solutions to more than $1.2 billion by 2016.
A123’s Nanophosphate EXT technology is scheduled to enter volume production in A123’s 20Ah prismatic cells during the first half of 2013. A123 is also evaluating plans to potentially offer Nanophosphate EXT across its complete portfolio of cell products.


Source: Green Car Congress