On Wednesday the conference was divided into parallel sessions on Large Format Batteries and Materials. Except for the final paper on Wednesday, this report deals with the Large Format Battery Session. The first paper was presented by Ralph Brodd of the Kentucky Argonne Battery Manufacturing R&D Center and titled, “Battery/Cell Manufacturing Cost Study”. This paper describes a detailed study undertaken to understand and quantify the differences in cost of manufacturing of Li-Ion cells in China and the U.S.
The 18650 cell, which is manufactured in far larger quantities than any other Li-Ion cell, was chosen as the basis for comparison. The costs were broken down into labor and materials costs. Labor fringe benefits as a percentage of salary were approximately the same in the two countries. At every level from unskilled direct labor to plant manager, the labor costs in China were a fraction of those in the U.S. Plant manufacturing volumes of 35 million and 350 million cells per year were assumed. At the smaller volumes, production in China had a clear cost advantage.
In large volume production, the cell costs were nearly equal, with Chinese costs slightly lower, even when freight and customs charges of approximately 4.5% for the Chinese product in the U.S. were taken into account. In agreement with an established rule of thumb, materials costs accounted for 75-80% of the total cell cost in each country. The paper concluded with a description of the mission and activities of the Kentucky Energy Research Center, which can be summarized as the support of U.S. battery industry’s technology and manufacturing capabilities.
Christophe Pillot of Avicenne presented the next paper, “The Battery Market for HEV, P-HEV and EV 2010-2020”. This presentation gave detailed projections of unit volumes of batteries for electric vehicles out to the year 2020. Only a few of the “high points” of this study can be presented here, as follows.
First, the volume of electric vehicle sales in 2020 projected by various organizations varies by roughly a factor of 10! In this presentation, such projections range from about 400,000 vehicles to more than 4,000,000 in 2020. Next, the total manufacturing capacity of EV batteries announced by all manufacturers greatly exceeds any of the projections for the sales of such batteries. Also, the need for hybrid electric vehicles (HEV) will continue to be met by nickel metal hydride batteries, while lithium-ion batteries will dominate the market for plug-in hybrids (PHEV) and purely electric vehicles (EV). Avicenne believes that electric vehicles will prove to be a disruptive technology in the automotive industry during the next decade and will have a profound influence on the battery industry as well. If this turns out was to be true, will EVs not also prove to be disruptive to the petroleum industry?
The next paper, “Nanophosphate Technology for Commercial, Industrial and Consumer Applications,” was presented by Joseph Adiletta of A123 Systems. The emphasis in this paper was on 12-volt “micro-hybrid” batteries for the start-stop application in vehicles powered by IC engines. A123’s lithium-ion phosphate batteries were said to have advantages over other solutions to this timely approach to decreasing vehicle emissions by stopping and starting the engine at each halt of the vehicle in traffic. Among these were weight savings, good high-rate charge acceptance, and safety. The start-stop application was predicted to be a billion-dollar sales opportunity in the year 2015.
The next paper was “Progress of BYD Battery,” presented by X. Shen of BYD. This presentation described the progress at BYD from the inception of research on LiFePO4 in 2002 to the production of 1.6GWh of EV batteries projected for 2011 sales. The progress was described in terms of materials, battery design, processing, and automated production. Aspects of cell materials and design, mechanical features of cell design, thermal management, safety features, and battery performance, including energy, power, and lifetime, were reviewed. Applications of these batteries to electric buses and cars were briefly described.
K. M. Abraham presented the next paper, “Materials Selection and Design of High Power Lithium Ion Batteries for HEV and PHEV The Nano versus Micron Dilemma.” Dr. Abraham holds joint appointments at E-KEM Sciences and at Northeastern University, Boston, MA. He began by describing the power and energy requirements of HEV, PHEV and purely electric EV applications. In choosing appropriate sizes for the particles of active material, the key characteristic is the lithium diffusion coefficient D in the solid particles approximately of micron diameter when D is on the order of 10-10 cm2/s and approximately 15nm in diameter when D is on the order of 10-14cm2/s. These examples are for high-rate discharge, essentially full utilization of the active material in 60s. This criterion leads to the important conclusion that LiFePO4 and Li4Ti5O12 need to be of nano size to achieve the same rates as micron-size NMC, NC, LCO and LMO in electrodes of comparable thickness. The “dilemma” of the title of this paper arises when the material’s electrochemical potential does not lie within the voltage window of stability of the electrolyte. Then smaller particles react more rapidly with the electrolyte to degrade system performance. The remainder of the paper described other design parameters that must be adjusted for operation at high rates, such as thin electrodes, low-resistance contacts, and the choice of the proper separator and electrolyte.
M. Fetcenko of Ovonic Battery presented the next paper, “Ovonic NiMH Building on Consumer and Vehicle Success to Address Stationary Applications.” This paper presented a case for Nickel Metal Hydride batteries as an attractive energy storage system for electric grid applications. The principal points were: the excellent life and safety records of NiMH in EV propulsion to date in approximately three million vehicles, the absence of a weight advantage for lithium-ion batteries over NiMH in stationary applications, and the potential for substantial cost and price reductions, with a projected selling price of $400/kWh.
The first paper after the lunch break was “An Update on the GM Chevy Volt and a Look at State Estimation to Enable Vehicle Integration of Traction Batteries,” presented by M. Verbrugge of GM. The Volt vehicle was described as an EV with extended range, in which operation for the first 40 miles of vehicle range will be all electric, and a gasoline-powered generator will provide additional range for more than 300 miles. That is, “electricity supplemented with gasoline.” The paper emphasized the development of algorithms for energy management, including accurate predictions of power capability and state of charge, as well as the “state of health” of the battery system. Details of the mathematical model were presented.
Next, J. Kim of Dow Kokam presented the paper, “Power to Energy Ratio Studies on a Variety of Dow Kokam Cell Designs.” This presentation reviewed the plans of the joint venture between Dow and Kokam to design and manufacture several sizes of large-format prismatic lithium ion cells. Goals for cost reduction, power, and several other attributes were presented. Three types of cells were described, each optimized for different goals: one for high energy (a 30Ah cell with 158Wh/kg), one for high power (40Ah and 143Wh/kg), and one for “ultra-high power,” having 30Ah capacity and 136h/kg. Plans of the JV to compete in both the EV and stationary energy storage markets were announced.
M. Andrew of JCI presented the next paper, “Advanced Battery Systems Driving Forward the Value Proposition through Technology Innovation.” This paper began with a lofty statement of the goal of transportation innovation to eliminate oil as a political weapon, economic disruptor, and environmental pathogen. The goal of JCI’s program is to reduce battery cost from approximately $1,000/kWh to $500/kWh by 2015. The targets of opportunity for cost reduction were materials, cells, packs, and systems for battery monitoring and control. A passive approach to thermal management was advocated. Systems mentioned as “beyond Li-Ion” were Li-S, Li-air and Zn-air, but no specifics were given on how the substantial technical obstacles to development of these systems might be overcome.
Following the afternoon break, R. Chamberlain of Boston Power presented the paper “Controlling Heat Generation in Lithium-Ion Batteries Designed for EV Applications.” After stating Boston Power’s intention of building up modules based on their Swing®lithium ion cells for use in applications ranging in energy from 1kWh to 50kWh, the author devoted the bulk of this presentation to the generation of heat in these cells and its dissipation from them. Forced-air cooling was recommended for high-rate applications such as EV propulsion. Examples were given of the temperature rise of the current generation of cells and comparisons with cells of other manufacturers of conventional cylindrical design. Other than the aluminum can, the specific cell features yielding improved thermal performance were not described in detail.
Next, J. Shelburne of Altairnano presented a paper entitled, “Altairnano Gen 2 Large Format Li4Ti5O12 Lithium-Ion Batteries Performance and Applications.” The author compared the performance of the new Gen 2 cells with the earlier Gen 1 cells, which gave no change in capacity after three years at 25ºC and only 1% decrease at 40ºC, a projected calendar life of 25 years and a self- discharge of about 1% per year. The 60Ah Gen 2 cell, though designed for energy storage, still gave 50% higher power than the Gen 1 cell; and it retained 97% of its capacity after 1000 2C/2C cycles at 55ºC. Energy storage systems with 1MW capacity have been ordered; these were projected to have round-trip energy efficiency of more than 90%. The performance of the Gen 2 cells, particularly their stability and projected life, is remarkable and derives in large measure from their titanate-based chemistry. The principal drawback is their cost.
The penultimate presentation for the Wednesday afternoon Materials session was a contribution from Lawrence Berkeley National Laboratory, “Studies of Degradation Phenomena in Li-ion Batteries,” presented by Robert Kostecki. For this reviewer, his presentation was one of the high points of the Battery Seminar. Dr. Kostecki’s lively and at times provocative style ensured the attentiveness of his audience. The paper’s main themes were the origins and mechanisms of the processes that determine cycle- and calendar-life of Li-ion cells.
Through the use of several analytical techniques, especially SEM, AFM, ex situ and in situ Raman microscopy and FTIR, diagnostic studies of composite cathodes in Li-ion cells were carried out. Degradation mechanisms of the cathodes were found to contribute appreciably to the related effects of impedance rise and capacity loss. Loss of inter-granular contact and carbon additive redistribution, as well as the formation of insulating films through electrolyte decomposition, were found to contribute to the degradation in performance. Advances in both materials science and electrode engineering were deemed necessary to improve electrode performance.
The first presentation of the last session of the Seminar, entitled “Integrating Batteries with the Grid,” was presented by H. Kamath of EPRI. The author gave an excellent overview of the role of batteries as energy storage systems supporting the electric grid. One sobering statistic for supporters of battery storage of grid-scale electricity is that 99% of worldwide grid energy storage is provided by pumped hydro. Sodium sulfur batteries lead other batteries with 316MW of installed capacity, followed by lead acid, nickel cadmium, lithium ion and redox flow, the latter with only 3MW. Interesting comparisons were made using as a base unit the 16kWh lithium ion battery pack of a Chevy Volt. One of these would supply a residential peak-shaving system, three would power a distributed-energy storage system for multiple dwellings, and 250 would be equivalent to a grid substation battery. The results of economic analysis for several grid-support activities were presented, with the results that bulk energy storage at the electric grid scale does not appear to be attractive for batteries, which are most likely to be valuable in distribution and ancillary services markets.
L. Gailliac of Southern California Edison continued the theme of grid-scale energy storage with his presentation, “Southern California Edison Energy Storage Efforts.” The speaker began by outlining the climate and energy policies of the state of California, which he described as the most aggressive in the United States. SCE supports these policies by several initiatives, including major test facilities and through demonstration projects and strategic planning. Paraphrasing the speaker, SCE approaches energy storage though “market pull” and not “technology push”. Their principal demonstration areas at present are residential energy storage (4kW, 10kWh); community energy storage (25-50kW, 50-100kWh); large transportable energy storage (2MW, 500kWh); and large-scale energy storage (8MW, 32MWh). The last two of these are planned for lithium ion battery demonstrations, and the 8MW system will be the largest lithium-ion demonstration carried out to date for this technology. A final conclusion of the paper is that the development of a smart grid system, incorporating energy storage, will be a many-year journey.
The next paper, entitled “Optimum Li Ion Technologies for Energy Storage,” was presented by B. Deveney of SAFT. In addition to its strength in the development of lithium ion cell technology, SAFT is scaling up its batteries to meet four different power ranges and application areas: residential power, small solar PV power, community energy systems, and grid stabilization systems. They see a large potential market in energy storage for renewable energy and are positioning themselves to provide various solutions through a modular approach to battery design.
H. F. Gibbard concluded the series of papers on large-scale battery systems with a contribution entitled, “Redox Flow Batteries for Energy Storage,” which reviewed redox flow batteries from their invention in the 1970’s until the present. He described these batteries as interesting for large-scale energy storage owing to their potential for low cost and long life. With very low specific energy, they are suitable for stationary applications but not for EVs. The paper described the iron-chromium system developed by NASA and in Japan in the 1970’s and 80’s and now under development by two start-up companies in California; the all-vanadium redox system, notable for its use of four different oxidation states of vanadium and for having the largest number and size of multi-kW and MW-scale demonstrations; and several other systems that have fallen by the wayside or are under development.
The next paper, “New Developments in Wireless Charging and the Wireless Power Consortium,” was given by K. Siddabattula of Texas Instruments. This paper described the principles of wireless charging and the progress that has been made in the charging of battery-powered small devices since the advent of the electric toothbrush charger. Interestingly, the developers and manufacturers of wireless power systems have not chosen to provide proprietary interfaces but have banded together to develop industry standards for their products. The use of such devices with cell phones, game controllers, notebook computers, and other portable devices was described.
The second-to-last paper of the meeting concerned the supply of lithium to the growing market for lithium ion batteries. It was presented by C. Merivale of Amalgamet, Canada and titled, “Accelerated Timeline to New Lithium Supply: The Canada Lithium Example.” This paper described in detail the process by which an open-pit lithium carbonate mine was brought to the stage of production. The 11-step process, from finding the deposit to funding of operations, required 6.8 years and cost approximately $225 million. The major incentive for seeking additional sources of lithium has been the growth of the lithium ion battery market and the even more rapid projections for the future growth of this market.
The final presentation of the Seminar was given by H-W. Praas of Texsys GMBH, Germany. Its title was “Field Failure, Safety and Production Aspects on Li Ion Batteries for 3C Application Past Three Years.” The author has had a unique perspective on battery safety for several years, not only being privy to the inspection of battery failures in the field but also having had the opportunity to visit and inspect the factories where they were manufactured. He provided many insights into battery safety, of which the following are two: “Low cost doesn’t mean low quality, and high cost doesn’t ensure high quality,” and “Batteries can begin safe but may not stay so.” Many examples were given of the two main classes of battery safety incidents consumer mis-handling and manufacturing defects. Surprisingly, he was allowed to vet the production processes in the factory and to document the numerous errors in manufacturing, equipment, lead alignment, and others that he found. An example of consumer mis-handling was given as follows: “A cell phone is dropped in a toilet, then dried with a hair dryer.” A piece of advice that he provided probably stimulated action from several members of the audience: “If you have a piece of equipment with lithium ion batteries that are several years but still functioning at some level, get rid of the batteries.” This series of cautionary tales and vivid pictures illustrating its points ended the conference.