Battery-level material cost model facilitates high-power li-ion battery cost reductions.
Under the FreedomCAR Partnership, 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 enhancing the calendar life and inherent safety of high-power Li-Ion batteries. 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 batteries designed to meet the requirements of hybrid electric vehicles (HEVs). 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 to the battery cost goals to determine the probability of meeting the goals with these cell chemistries. The most recent freedomCAR cost goals for 25-kW and 40-kW power-assist HEV batteries are $500 and $800, respectively, which is $20/kW in both cases. In 2001, ANL developed a high-power cell chemistry that was incorporated into high-power 18650 cells for use in extensive accelerated aging and thermal abuse characterization studies. This cell chemistry serves as a baseline for this material cost study. It incorporates a LiNi0.8Co0.15Al0.05O2 cathode, a synthetic graphite anode, and a LiPF6 in EC:EMC electrolyte. Based on volume production cost estimates for these materials-as well as those for binders/solvents, cathode conductive additives, separator, and current collectors--the total cell winding material cost for a 25-kW power-assist HEV battery is estimated to be $$399 (based on a 48- cell battery design, each cell having a capacity of 15.4 Ah). This corresponds to {approx}$$16/kW. Our goal is to reduce the cell winding material cost to <$10/kW, in order to allow >$10/kW for the cell and battery manufacturing costs, as well as profit for the industrial manufacturer. The material cost information is obtained directly from the industrial material suppliers, based on supplying the material quantities necessary to support an introductory market of 100,000 HEV batteries/year. Using its battery design model, ANL provides the material suppliers with estimates of the material quantities needed to meet this market, for both 25-kW and 40-kW power-assist HEV batteries. Also, ANL has funded a few volume-production material cost analyses, with industrial material suppliers, to obtain needed cost information. In a related project, ANL evaluates and develops low-cost advanced materials for use in high-power Li-Ion HEV batteries. [This work is the subject of one or more separate papers at this conference.] Cell chemistries are developed from the most promising low-cost materials. The performance characteristics of test cells that employ these cell chemistries are used as input to the cost model. Batteries, employing these cell chemistries, are designed to meet the FreedomCAR power, energy, weight, and volume requirements. The cost model then provides a battery-level material cost and material cost breakdown for each battery design. Two of these advanced cell chemistries show promise for significantly reducing the battery-level material costs (see Table 1), as well as enhancing calendar life and inherent safety. It is projected that these two advanced cell chemistries (A and B) could reduce the battery-level material costs by an estimated 24% and 43%, respectively. An additional cost advantage is realized with advanced chemistry B, due to the high rate capability of the 3-dimensional LiMn{sub 2}O{sub 4} spinel cathode. This means that a greater percentage of the total Ah capacity of the cell is usable and cells with reduced Ah capacity can be used. This allows for a reduction in the quantity of the anode, electrolyte, separator, and current collector materials needed for each cell. Additional cost savings, in the areas of electrolyte salt and anode binder materials, could be realized. Details of this material cost study and recommendations for future low-cost material R&D will be provided.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- EE
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 982580
- Report Number(s):
- ANL/CMT/CP-110657; TRN: US201015%%1190
- Resource Relation:
- Conference: Power Sources for Transportation Applications Symposium, 204th ECS Meeting; Oct. 14, 2003 - Oct. 15, 2003; Orlando, FL
- Country of Publication:
- United States
- Language:
- ENGLISH
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