. "Appendix F: Estimation of Lithium-Ion Battery Pack Costs." Transitions to Alternative Transportation Technologies--Plug-in Hybrid Electric Vehicles. Washington, DC: The National Academies Press, 2010.
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Transitions to Alternative Transportation Technologies—Plug-In Hybrid Electric Vehicles
FIGURE F.1 Historical cost reduction experience for NiMH battery packs and for Li-ion battery packs. Recent experience does not suggest rapid further cost reductions. SOURCE: T.Q. Duong, Update on electrochemical energy storage R&D, presentation to the committee, Washington D.C., June 2009.
Anderman predicts that the cost of Li-ion batteries will remain at around $600/kWh even with increased production (Anderman, 2007).
Kalhammer et al. (2007) project costs from $350/kWh to $400/kWh (nameplate) for PHEV-40 battery packs at volume production (100,000 to 200,000 units per year). Costs for PHEV-10 battery packs are projected to be $560 to 860/kWh for production at 100,000 to 625,000 units per year.
The future cost estimates in this report are higher than most, but not all, other projections, especially the DOE goals. The committee concluded that reductions greater than 50 percent in battery costs are unlikely over the next two decades without a major technology breakthrough, because meeting battery durability and safety goals could slow cost reductions. For example, raising the SOC range would be a significant cost saver but could compromise durability if that put too much stress on the cells.
Cost reductions are likely to come mainly from improvements in technology, with lesser contributions from manufacturing improvements, improved yield, and manufacturing scale.5 Technology will continue to improve, but it is already well developed for current Li-ion cells. Cells for automotive applications will be bigger than current Li-ion cells but are otherwise not very different in either chemistry or manufacturing processes. Thus the potential for large cost reductions from technology improvements is limited. Furthermore, materials represent more than half the cell cost (Nelson et al., 2009), and these costs are unlikely to drop dramatically.
Economies of scale are often cited as a factor that can drive down costs, but hundreds of millions to billions of Liion cells already are being produced in optimized factories. Building more factories is unlikely to have a great impact on costs. The cost of the battery pack enclosure that holds the cells, the electronics required to monitor and control each cell to prevent over-charging and run-away, and the temperature control system to manage battery pack temperature are a major portion of the total battery pack cost. These components are unlikely to undergo larger cost reductions than the cells, and so the committee maintained the same ratio of twice the cell cost for the pack.
Li-ion batteries have undergone large cost reductions over the last 10 years, but the costs seem to be leveling out. Costs of NiMH battery pack for HEVs have declined only modestly in recent years, as shown in Figure F.1, suggesting that further major cost reductions are not very likely without technology breakthroughs, which this study did not try to project.
The committee considered all these projections and other information to come up with its estimates for 2030 future costs of about $500/kWh or, under more optimistic assumptions, of about $360/kWh.
According to one estimate, cell costs could drop by more than 50 percent by 2015, with almost all of that decrease coming from technology and process improvements (D. Vieau, A123 Systems, presentation to the committee, Washington, D.C., May 2009).