from June 2012 ABT

meeting report

29th Florida Battery Seminar

Ft. Lauderdale, FL, USA

March 11-15, 2012

The 29th International Seminar and Exhibit was held in Ft. Lauderdale, Florida, March 11-15, 2012. There were about 500 attendees and 26 exhibitors. It was not possible to discuss all of the interesting presentations here. Therefore, the author selected 10 presentations that were of particular interest. CDs of all of the presentations and the tutorials are available at www.powersources.net

The conference started on Monday morning with two tutorials by Dr. A. Aurbach, who gave a detailed analysis of new developments for advanced battery materials followed by C. Pilot, who discussed the rechargeable battery market and the expected growth for electric vehicle and energy storage batteries. Both seminars were well attended and very informative, but were a separate activity from the conference itself.

Yi Cui reported on the use of nanostructured battery materials, especially silicon and sulfur coupled with silicon nanowire fibers. The silicon nanowire anodes in half-cells gave steady 3Ah/g capacity on C/5 cycling. The small size allowed easy strain relaxation and free space to expand and contract. Cui describes several different structures of sulfur with PEG and graphene film that also show good promise. Sulfur cathodes formed by encapsulating the sulfur in a graphene body and sulfur contained inside a hollow carbon nanotube gave good cycle life. The Si nanowire-Li2S chemistry has a theoretical capacity of 1550Wh/kg and an experimental laboratory cell gave 630Wh/kg.

Adrian Pullen of TIAX reviewed the scale-up and commercialization of a new nickel-based Li-ion cathode material, CAM-7, that is said to have superior performance. From inception to the decision to commercialize the technology took 10 years and is typical of the time line for development of new battery materials. CAM-7 has a capacity, open circuit voltage of 4.3V and 210mAh/gram. Very few details on the exact chemical composition were given, but this is a good example of the time and effort required to develop a commercial battery material.

Kevin Eberman discussed the nanostructured silicon-tin (a-LixSiSn) alloy anode materials under development at 3M. The nanostructured silicon-tin anode materials have the ability to absorb and release lithium in an electrochemical reaction and are a direct replacement for the graphite materials previously used in Li-ion cells. The electrode reaction is reversible and as such, the particles remain intact as they expand and contract as the cells are charged and discharged. The materials that consist of two phases produce charge-discharge curves that have plateaus. The 3M Si-Sn alloy yields an amorphous material with high conductivity, a characteristic sloping discharge curve and about 800+ mAh/g.

David Howell of DOE presented an overview of the DOE programs. The target goals are 300Wh/kg, 500Wh/l and 5000 cycles. The program supports R&D efforts at 19 different universities and 16 industry partners. The path forward for Li-ion batteries for electric cars is aggressive. By 2030 the goals are about 500Wh/l and 250Wh/kg with a 60% reduction in cost. In 2010 DOE Annual Energy Review, transportation accounted for 72% of oil consumption, electric power 1%, residential and commercial 17% and industry 41%. It takes time to realize the benefits of new technology in the vehicle arena. Maximum market penetration usually occurs in 15 to 20 years as was the case for variable valve timing and multi-valve timing to reach maximum market penetration. The same could be true for the electric vehicles now just being introduced. The U.S. vehicle market stands at 12 million new cars and light trucks sold in 2010 with about 240 million light duty vehicles on the road. The DOE funding for 2012 includes about $12 million for Basic Energy Science, $20 million for the HUB and $95 million for EERE programs.

Michael Fetcenko reported that Ovonics was rescued from bankruptcy when they were acquired by BASF in their entirety. The cathode materials development at Ovonics expands BASF’s presence in the battery market. Ovonics will integrate their cathode materials capability into BASF and continue their industry leading Ni-MH activity. The company has developed a new high performance AB2 metal hydride alloy that contains no rare earth elements and counters the price increase in rare earth materials by China. The price of rare earth hydride materials has more than doubled since 2011 when China began restricting exports. The Ni-MH battery is the choice for hybrid cars and over 4 million cars have been sold worldwide. In stationary applications for UPS and smart grid applications the Ni-MH has the lowest 20-year life cycle cost over lead acid, Ni-Cd and Li-Ion with tolerance for overcharge and deep discharge and a wide temperature range of operation from -30° to +70°C.

George Kerchner of PRBA reported on the ICAO Dangerous Goods Panel working group meeting in Montreal in February had significant concern with “bulk shipments of lithium ion batteries. Equipment packed with or containing exempted cells are not a significant concern. The lack of pilot notification and acceptance check was a concern. The investigation of the UPS plane accident in Dubai revealed significant non-compliance of regulations for lithium-ion battery dangerous goods regulations. New exemption limit was established for lithium and lithium-ion cells and batteries. Two or more batteries or eight cells in one package must be shipped as dangerous goods. Changes are effective January 1, 2013. The next challenge is the shipping of large Li-ion vehicle batteries on aircraft where the 35kg limit is problematic.

Jiqiang Wang of CIAPS reported that China has become the largest EV producer with 18.3 million produced in 2010, 18.5 million in 2011 and 20 million expected in 2012. The government-funded programs are directed at energy security as oil imports are rising rapidly. The E-Taxi demo in Shenzhen with 250 cars and more than 100 e-buses. The E6 taxi has a 60kWh battery and has a range of 200km. The cost of electricity is 48RMB/charge. The taxi demonstration involved automatic replacement rather than direct charge. Energy storage demonstration using Li-ion cells has 3MW wind generation capability with 1MW/MWh Li-ion storage system.

Brian Barnett and Suresh Siramulu of TIAX raised basic issues on safety and triggers for incidents as well as proposed a new framework for safety and safety testing. The electrical energy stored in the cell can raise the cell to about 800°C and the combustion of the electrolyte can raise the cell temperature to over 1800°C. There are a wide variety of organizations that have developed cell and battery test methods. It is not clear that the safety tests always screen cells and batteries for safe operation. Test conditions, changes in test protocol and cell orientation, etc. can change the test results. For instance nail penetration produces an extremely low resistance short with little cell heating until an explosion occurs. Also, there appears to be little relationship between the DSC data and whether or not thermal runaway occurs. The whole issue becomes that safety is a system issue and not necessarily related to a specific cell material. TIAX is developing a new early detection methodology to identify early detection and initiation of intervention of internal shorts of various types.

Linda Ganes of Argonne National Laboratory discussed the viability of lowering electric vehicle battery costs by recycling spent/underperforming batteries. Recycled materials result in lowering the cost of scarce materials and reducing the effect of limited resource restricting the cost and availabilty for elements such as nickel and cobalt. It includes the second use of a battery after its performance characteristics deteriorate and no longer meet requirements of the initial application, such as using underperforming vehicle batteries in energy storage applications. Reuse does delay the return of the scarce materials for new batteries and increased toe demand/cost of virgin material. Lithium and cobalt can be recovered by the present Toxco process. Standardization of the chemistry and cell construction would lower recycling costs.

Robert Kostecki of Lawrence Berkeley Laboratory discusses failure modes of Li-ion cathode materials. Composite cathodes failure mode involves structural damage and oxidation of carbon-conducting materials. There is electrophoretic movement of carbon particles toward the anode lowering the electronic conductivity of the cathode. The state of charge in the cathode varies within the cathode. There is no structural/chemical degradation of the active material itself. These processes increase the impedance and a loss of useful capacity.

The 30th International Battery Seminar and Exhibit will be held on March 11-14, 2013, at the Broward County Convention Center in Ft. Lauderdale, Florida.

About the Author: Dr. Ralph J. Brodd has worked in the battery industry for over 40 years and has broad experience in the technology and market aspects of the electrochemical energy conversion business. His experience ranges from carbon-zinc to lithium systems in primary cells and from lead acid and Ni-Cd to advanced lithium and lithium-ion systems in rechargeable cells, including fuel cells and ultra-capacitors.