meeting report
27th International Battery Seminar and Exhibition - Part ll
Ft. Lauderdale, FL USA
March 15-18, 2010
- Bronxville, New York
- tbmereddy@aol.com
Part II - read Part l
The Wednesday format also had two parallel sessions, one on large format batteries and the other on recycling, which this year was consolidated into the battery seminar. Presentations from the large format session will be covered here.
The first talk was given by Robert Bienenfield of American Honda Motors who spoke on An Overview of Advanced Technologies. He discussed the worldwide automotive market where there currently are 1 billion vehicles on the road and projected to grow to 3 billion. A 50% reduction in CO2 emissions is needed to counteract global warming. Cars using ICEs typically emit 100g of CO2/mile. Downsizing the Accord and Civic models will be challenging for Honda. The use of natural gas will reduce CO2 emissions by 25%. Diesel engines use 25% less fuel but emit more CO2 per gallon with a net savings of 15-20% while HEVs provide a 30-50% improvement. Currently, the U.S. population is giving climate change a low priority. The U.S. has a "dirty grid" because of the use of coal as an energy source and the introduction of PHEVs and EVs won’t reduce CO2 emissions that much.
The second talk on Wednesday morning was given by Andy Chu, vice president at A123 Systems, on Next Generation Energy Storage for Grid and Transportation. He first discussed transportation applications for the LFP technology developed by A123. A 20Ah prismatic pouch cell has been developed for vehicles. This cell will be incorporated into a prismatic battery pack which is more efficient volumetrically and will employ a series-parallel design. Cooling will be provided along the sides and through a plate on the bottom. In addition to automobiles, these batteries may be employed in hybrid buses and Volvo trucks which use a 12V, 60Ah battery. Applications in high-end micro hybrids may also occur. Mass production of the Li-ion batteries will reduce cost and open up the battery energy storage systems (BESS) market. An initial 12MW BESS system in Chile was described.
The third talk was given by Mark Verbrugge of the GM Research Labs in conjunction with HRL laboratories and was entitled: Traction Batteries and Automotive Needs with an Emphasis on Integration Issues and Solid-State Chemistry.
Dr. Vebrugge showed a ragone plot which clearly indicates that lithium-ion batteries are the system of choice for use in PHEV and EV applications. He discussed various couples for EV use. LFP and LTO are attractive because of their stability. LFP/graphite is not impressive because of its low specific energy. LFP is attractive because of its stability, rate capability, flat discharge voltage, cycle life and potentially low cost. The graphite anode is a popular choice because of its good specific capacity, rate capability, cycle life and cost. Extended-range EVs require a power /energy ratio around 8 and the LFP/graphite combination meets this need. A mechanism for the degradation of the LFP/graphite cells was presented. dV/dQ plots have been made from discharge curves and indicate that Li loss is the limiting factor in capacity degradation. An empirical equation has been employed to predict capacity loss as a function of total charge throughput in a cell. The equation models capacity loss in a qualitative way. The proposed mechanism for capacity loss is the cracking of the SEI layer on graphite, leading to the formation of more SEI and the loss of lithium from the cell.
Another equation was presented to predict capacity loss due to both calendar life and cycle life. Ways to predict the state-of-charge (SOC) from discharge curves were discussed and the possibility of using LTO-graphite anodes to allow determination of the SOC was proposed.
The next talk was given by Mohamed Alamgir of Compact Power (CP), a U.S. subsidiary of LG Chem of South Korea, on From Cell Phones to EVs: Evolution of Performance Demands on Li-ion Batteries. The sizes of Li-ion batteries have grown from 2Ah for cell phones to 20kWh for EVs, a factor of 104. CP uses a LMO spinel in its pouch cell which is capable of charge and discharge at 10oC rates at room temperature and 5oC at low temperature for cold-cranking engines for HEV use. It has demonstrated abuse tolerance at high voltage. Its calendar life is calculated to be 10 years. This cell employs a safety reinforced separator (SRS) which consists of a microporous PE material with ceramic edges. When subjected to a hot-tip test at 45oC, there is no hole propagation. The Hyundai Elantra uses an HEV pack of this type. EVs require batteries from 10-40kWh energy and power to 5C. Operation over a wide SOC range is also required for EVs.
The next presentation was given by John Shelburne of Altairnano on Nano LTO-Based Large Format Lithium-Ion Batteries and Battery Systems. Altairnano has developed two cells using LTO. The first has a capacity of 11Ah and is designed for vehicular use while the second is a 50Ah product for transportation and energy storage applications. Cells with mixed-metal oxide cathodes have demonstrated low self-discharge, high-power capacity and long cycle life. In the latter category cells have been cycled 9,000 times with 90% capacity retention. Cycling at 55o has also been demonstrated. Accelerated calender-life studies suggest a 25-year life can be obtained. Gen 2 cells employ NMC cathodes and have demonstrated better thermal stability than Gen 1 cells in hot-box safety tests. PHEV demonstration tests with the Toyota Prius provided 57 and 60mpg. Tests on hybrid and full electric buses using Altairnano batteries are being carried out. Altairnano has also produced a battery energy storage system of 1MW power and 256kWh energy in a 53-foot trailer. The modules for this system consist of 56 cells with 50Ah capacity. The BESS performed well in frequency regulation tests.
The first talk in the Wednesday afternoon large format session was given by Joon Kim of Dow-Kokam on Application of the Kokam Superior Li Polymer Battery (SLPB) in Electric Vehicles. Dow-Kokam employs a folded electrode bi-cell design and produces cell modules and battery management systems. Production capacity in North America is 1200MWh/year. They are also producing EV modules in Europe and have business relationships in Asia. Gen. II designs are undergoing a test matrix program. Dow-Kokam produces both energy and power cells which have different designs.
The next presentation in the Wednesday PM large-format session was given by Michael Fetcenko of Ovonic Battery Company on Ovonic NiMH-Strong for Consumers and Vehicles with Room for Growth. He reviewed the current status and future prospects for NiMH technology and emphasized Ovonic’s strong patent portfolio. The specific energy of NiMH AA cells has doubled from 54 to 110Wh/Kg from 1991 to 2009, while the capacity has increased from 1100 to 2700mAh, making this cell an attractive rechargeable replacement for alkaline manganese primaries. The development of pre-charged, NiMH cells is the result of three technological improvements: 1) the encapsulation of Ni (OH)2; 2) the use of a sulfunated separator and 3) the change to a lower corrosion metal hydride anode.
In the automotive market, over 2 million HEVs using NiMH batteries were sold from 1997 to 2008. Newer HEV models using NiMH technology, such as the Ford Fusion, are currently being introduced. The possible use of NiMH in PHEVs and EVs were discussed. Ovonic is using its U.S. nickel oxide facility to produce NCA and NCM cathode materials for Li-ion batteries. Mr. Fetcenko presented a strategy for doubling the current DoD and cutting the cost in half so NiMH can maintain its present dominance in the HEV market. He also presented an analysis indicating that life-cycle costs would be lower for NiMH batteries in telecom applications than competing technologies. The possibility of using NiMH in battery energy storage systems was also discussed.
The next talk was given by Dr. John M. Miller of Maxwell Technologies on: Ultracapacitors: The 10s boost for batteries. He pointed out that Maxwell’s ultracapacitors can augment the power capability of batteries for HEVs and EVs. Ultracaps can absorb or produce a ten-second burst of power for a million cycles which will increase the operational life, reduce the current and lower thermal burden on vehicular batteries. Low-temperature performance is a limiting factor in EVs and PHEVs. The use of a hybrid battery-capacitor combination will allow improved reliability and life at low temperatures, full energy capture during regenerative breaking and full power delivery at end-of-life (EOL). The use of higher specific energy batteries to reduce cost can also occur and this will improve overall vehicle behavior. Test data showing improved battery performance at low-temperature was presented. Dr. Miller described a new dry process to lower ultracap cost and improve performance.
Next, Mark Shoesmith of E-One Moli Energy spoke on: The Development of Li-ion Cells for PHEV and Other Applications. He described the evolution of the 18650 and 26700 cell sizes manufactured by E-One Moli Energy from 2003 to 2010. The current production rate is 8 million cells/month. High-power cells are capable of operation to 10C continuous and 20C pulsed discharge. Various design features are employed to provide low internal impedance and control cell heating. The current IBR-18650 B cell is capable of 25Amp discharge and provides a capacity of 1.5Ah while the IBR-26700 A cell can be discharged to 40Amps and has a capacity of 2.8Ah. Discharge data and cell impedance as a function of DoD were presented for both cell types. These cells are intended for use in PHEVs such as the Ford Escape Hybrid-10 and are capable of a specific power to 2.3kW/Kg and can be discharged to 2.5V. The IBR-26700 A cell has delivered 2500 cycles at 23o. The various applications for these cells were described. The 18650 is suitable for use in EVs while the 26700 is intended for PHEVs.
The subsequent talk was given by Steven Ruth of China BAK Battery Co. on The Automotive Applications for BAK Li-ion Batteries. CBAK produced LFP cells which are assembled into 3.2V modules (1SX75P) with a capacity of 200Ah. These are stackable to produce the required voltage and capacity and contain an integrated BMS. They have been employed for a demonstration EV city bus in Singapore and several automotive projects in China. The city bus project employs 26650MP LFP cells providing 3.2V and 2.7Ah. A cycle life greater than 1K has been obtained at 1C discharge to 2.0V and 100% DOD. 18650 NMC cells have been produced and assembled into 7.4V modules (2PX535) and modules stacked to provide a 35kWh, 400V system with an integrated BMS. This system is currently employed in an EV being marketed in North America. Other potential applications were discussed and CBAK’s product line-up was presented.
The next to the last presentation on Wednesday afternoon was given by Michal Wolkin of Better Place on: Better Place Model, Services, Battery and Battery Switch Solution. He described the Better Place plan to accelerate the transition to EVs. This will be accomplished by making EVs more affordable to own and use by partnering to develop recharging stations to reduce CO2 emissions and foster the development of renewable energy sources. In the Better Place concept, the consumer does not own the battery. It is provided by Better Place which deploys recharging stations and swap-out facilities for charged batteries and charges the driver based on use. Renault is producing 100,000 ZE Fluence EVs with a range of 100 miles for use as a test of the Better Place concept. Better Place has ordered 10,000 EV batteries for this test.
The final presentation on Wednesday afternoon in the large format session was given by Haresh Kamath of EPRI on Lithium-ion Batteries in Utility Applications. He discussed the structure and function of EPRI and then discussed how the current electric grid in the U.S. operates and how it is changing. Storage systems provide various functions such as power quality, peak shaving, frequency regulation and spinning reserve in the electrical grid. At present energy storage is small and consists primarily of pumped hydro with compressed-air energy storage (CAES) a distant second. An analysis of capital cost as a function of discharge duration was presented for various storage systems. Underground CAES, pumped hydro and Li-ion batteries and the lowest cost, in that order, for six-hour discharge. EPRI’s near-term strategy for bulk storage (50MW-several hours), substation-storage (1-10MW for 2-6 hours) and distributed (15-25kW for 2-4 hours) was presented. An economic comparison shows Li-ion BESS technology is the lowest cost for short durations (under one hour) and CAES for longer durations. Since many billions of U.S. dollars have been spent on Li-ion manufacturing technology, lower-cost batteries (less than $150/kWh) should result with costs even lower than lead-acid. The use of spent batteries from EVs and PHEVs should provide even lower costs. Future technological innovations may provide even lower costs than that.
The first talk in the Thursday morning large-format session was given by Dr. Cyrus Ashtiani of EnerDel on: The Role of the Anode in Lithium-Ion Batteries. He discussed the different requirements for batteries for HEVs, PHEVs and EVs and the four different chemistries being employed by EnerDel to meet the requirements. Mixed oxide-hard carbon prismatic cells are being developed to meet the high-energy EV market and power/energy cells for plug-in hybrid vehicles. For EVs and PHEVs, NMC/hard carbon and high-voltage Mn spinel/LTO combinations are being evaluated. For HEVs, LMO-spinel/hard carbon and LMO-spinel/LTO combinations are under development. A discussion of the lithium intercalation process in various carbons was presented. The electrochemical properties of graphite, hard carbon, soft carbon and LTO were discussed and the several technical advantages of LTO were enumerated. However, the use of LTO entails a 1.5V penalty in cell voltage and about one-half the specific capacity of graphite. The LTO structure must include nanoparticles to provide conductivity. Carbonaceous materials continue to dominate the Li-ion battery market and most cells employ hybrid carbons which are not easily classified. LTO continues to provide advantages in terms of safety and cycle life. Silicon and other alloy anodes hold the promise of much higher specific energy.
The second presentation on Thursday was given by Bridget Deveney on: SAFT’s Super-Phosphate™ Technology. SAFT is creating a plant for the production of large-format cells in Jacksonville and the work presented has been carried out by its space and defense division. Various U.S. DoD programs were described and the specifications for nine lithium-ion cells using both NCA and LFP produced by SAFT in Maryland were given. The characteristics of the VL45E (NCA cathode) and the VL 445 Efe cells were compared. The NCA product has higher specific energy and energy density but lower maximum discharge current than the LFP product. The so-called super-phosphate product produces higher voltage and capacity than the earlier LFP product. Operation of the VL10VFe cell on 60amp discharge at -30oC was demonstrated. LFP technology is more sensitive to higher temperatures than cells with layered-oxide cathodes. Cycling at the 1-C rate at +30oC and DoD provided 4,000 cycles. Overcharge testing on standard and improved LFP cells and an NCA cell were shown. LFP batteries display flat discharge curves, and storage at 100% SOC has little impact on calendar life. Both cobalt and manganese phosphate cathode materials were under development.
The next presentation was made by Alan McIlwaine of Valence Technologies on: U-Charge Configurability and Flexibility in Return-to-Base Electric Delivery Vans. The U-Charge installed base consists of 12V and 18V modules from 40 to 120Ah capacity. These are employed in several trucks and delivery vans. Test results on a 3.5 ton unloaded vehicle as recorded in data-logger were presented. Pack voltage and temperature were shown with both 70 and 90kW motors. Driving distances were 135 and 106 miles respectively with temperature increases of 13oC and 12oC. Results on the 3.5 ton vehicle while loaded and a 7.5 ton unloaded truck were also reported. The latter vehicle ran 31 miles with a 15oC temperature increase. Data from a HEV Ombinibus being tested in London showed good reliability over a six-month trial with 98% capacity retention. Examples of other vehicles being tested were also presented.
The next presentation was given by Dr. K. M. Abraham of E-KEM sciences on: Beyond Today’s Lithium-Ion Batteries for Long-Range EV. He discussed the technical requirements for HEVs, PHEVs and full EVs. The specifications for the Tesla Roadster and Tesla Model-S sedan were given. A full EV with a 300 mile range would require cells with a specific energy of 315Wh/Kg and an energy density of 780Wh/L to provide 75KWh of energy. The properties of cells using LCO, NCA and NMC cathodes were delineated. 18650 cells using NCA have achieved a specific energy of 240Wh/Kg and an energy density of 630Wh/L. A new cathode material with 200-220mAh/g and 4.5V could achieve 300Wh/Kg but would require the use of a high-voltage electrolyte and may present safety concerns. The use of a LiNiO2 cathode with a Si anode may provide 300Wh/Kg. Other alternates to Lithium-ion were presented. To provide a battery for EVs with a 300-mile range, Dr. Abraham suggested the use of the lithium/oxygen couple which has a theoretical specific energy of 11,000Wh/Kg. He believes it may achieve 2000Wh/Kg in use. Other couples with low equivalent weight were also presented. The cyclability of the Li metal anode is a major issue. The Li/FeF3 system which has a multi-electron displacement reaction was given special attention because of the work of Prof. Glenn Amatucci of Rutgers on this couple. Dr. Abraham returned to the Li/O2 couple as the system of choice for long-range EV use. Complete reduction of O2 has not been achieved and the round-trip voltage efficiency of this system is less than 75%. The plating of highly reactive Li metal on recharge is also a major problem but the use of Li alloys may reduce this issue.
The next presentation was given by Dr. H. Frank Gibbard of Gibbard R and D Corp. on Resurrection of Li/Air Rechargeables from the 1980s: Is This Justifiable? Dr. Gibbard rebutted Dr. Abraham’s optimism about the use of Li/air batteries for EV propulsion. He cited earlier attempts to develop rechargeable Li metal batteries in the 1980s, in particular the work of Littauer and Tsai on a Li/air system in an aqueous electrolyte. He presented thermodynamic calculations for metal/air batteries by Mark Salomon, et. al and cited their paper pointing out that solubility of the product limits utility. He cited earlier attempts by Moli Energy and Avestor/Hydro-Quebec to produce rechargeable Li metal batteries. In both cases, the manufacturers had to recall the product due to safety problems and Avestor went bankrupt. In the latter case, a polymer electrolyte was employed so there was no liquid electrolyte to react with plated lithium. One current design for Li/air technology employs a solid lithium-ion conductor to cover the Li metal anode and produces an insoluble Li2O2 product. A second design employs an organic electrolyte in contact with Li metal and an aqueous electrolyte in contact with the air electrode with a LiSiCoN solid electrolyte between the compartments. This cell operates at the very low current density of 0.5mA/sq.cm. and is not suitable for EV use. Dr. Gibbard’s conclusions were: 1) rechargeable Li/air batteries may be developed but they will be low power, will likely have limited cycle life and will only find applications in niche markets; and 2) if large, high-power systems are developed, there is a high probability they will be unsafe.
The final presentation of the seminar was given by Dr. Hisashi Tsukomoto of Quallion on: Quallion Matrix Battery Technology for Distributed Energy. Quallion employs a patented matrix design to assemble series-parallel arrays of cells into batteries. This provides additional safety in case a cell overheats and prevents propagation of a thermal runaway event and allows the battery to function using the parallel cell string if one cell fails. A test on a 8SX12P battery of 18650 cells showed that the battery continued to operate when one or more cells were removed on a LEO satellite test. The matrix pack also requires less balancing than conventional battery packs. This approach also allows the construction of packs with high energy or high power. Quallion builds its matrix batteries using a heat-absorption material which separates the cells and helps reduce thermal runaway situations. The results of immersion, partial nail-penetration and crush tests were reported. The design of a battery for the Aries Launch Abort System was described. It employs 378 commercial high-power 18650 cells to produce 140V, 15Ah, and 28V, 1.5Ah taps. Battery designs for other applications were also described.
- read Part l