Materials cost evaluation report for high-power Li-ion batteries. (2003)

The U.S. Department of Energy (DOE) is the lead federal agency in the partnership between the U.S. automobile industry and the federal government to develop fuel cell electric vehicles (FCEVs) and hybrid electric vehicles (HEVs) as part of the FreedomCAR Partnership. DOE's FreedomCAR and Vehicle Technologies Office sponsors the Advanced Technology Development (ATD) Program--involving 5 of its national laboratories--to assist the industrial developers of high-power lithium-ion batteries to overcome the barriers of cost, calendar life, and abuse tolerance so that this technology can be rendered practical for use in HEV and FCEV applications under the FreedomCAR Partnership. In the area of cost reduction, Argonne National Laboratory (ANL) is working to identify and develop advanced anode, cathode, and electrolyte components that can significantly reduce the cost of the cell chemistry, while simultaneously extending the calendar life and enhancing the inherent safety of this electrochemical system. The material cost savings are quantified and tracked via the use of a cell and battery design model that establishes the quantity of each material needed in the production of batteries that are designed to meet the requirements of a minimum-power-assist HEV battery or a maximum-power-assist HEV battery for the FreedomCAR Partnership. Similar models will be developed for FEV batteries when the requirements for those batteries are finalized. In order to quantify the material costs relative to the FreedomCAR battery cost goals, ANL uses (1) laboratory cell performance data, (2) its battery design model and (3) battery manufacturing process yields to create battery-level material cost models. Using these models and industry-supplied material cost information, ANL assigns battery-level material costs for different cell chemistries. These costs can then be compared with the battery cost goals to determine the probability of meeting the goals with these cell chemistries. As can be seen from the results of this materials cost study, a cell chemistry based on the use of a LiMn{sub 2}O{sub 4} cathode material is lowest-cost and meets our battery-level material cost goal of <$250 for a 25-kW minimum-power-assist HEV battery. A major contributing factor is the high-rate capability of this material, which allows one to design a lower-capacity cell to meet the battery-level power and energy requirements. This reduces the quantities of the other materials needed to produce a 25-kW minimum-power-assist HEV battery. The same is true for the 40-kW maximum-power-assist HEV battery. Additionally, the LiMn{sub 2}O{sub 4} cathode is much more thermally and chemically stable than the LiNi{sub 0.8}Co{sub 0.2}O{sub 2} type cathode, which should enhance inherent safety and extend calendar life (if the LiMn{sub 2}O{sub 4} cathode can be stabilized against dissolution via HF attack). Therefore, we recommend that the FreedomCAR Partnership focus its research and development efforts on developing this type of low-cost high-power lithium-ion cell chemistry. Details supporting this recommendation are provided in the body of this report.