HEV Batteries

In late 1998 and early 1999, Argonne worked with the Department of Energy (DOE) to organize and implement an applied battery R&D program. The goal of this program was to help industrial developers of Li-Ion batteries overcome key barriers in using this promising technology in hybrid electric vehicles (HEVs). Argonne is the lead laboratory for this program, the Advanced Technology Development (ATD) Program. Also, some of the materials research being conducted for DOE's exploratory research program, the Batteries for Advanced Transportation Technologies (BATT) Program, is related to high-power electrode materials suitable for use in HEV applications. Finally, Argonne is frequently contacted by industrial firms to work with them on collaborative R&D projects. Some of these projects are directly or indirectly linked to Li-Ion HEV battery technologies.

DOE's Applied R&D Program for HEV Batteries

Four other DOE national laboratories (Brookhaven, Idaho, Lawrence Berkeley, and Sandia) participate in this Argonne-led ATD Program, to help industrial developers of high-power Li-Ion batteries overcome the four key barriers for this technology in HEV applications. These four key barriers are:

Cost of $20/kW
Calendar life of 15 years
Adequate abuse tolerance for use in light duty vehicle applications
Acceptable performance at temperatures down to -30°C

The -30°C performance issue was added as a barrier in 2006, when it was discovered that the industrial developers had to oversize their batteries to meet this requirement.

The ATD program addresses these barriers by identifying the factors that control life, abuse tolerance, and low-temperature performance in different Li-Ion cell chemistries. The factors controlling life are studied using accelerated aging of cells, detailed diagnostic studies, and Li-Ion cell transport models. Similar methods are used to study low-temperature performance limitations. In the area of abuse tolerance, the contribution of every individual cell component is quantified. The results of these studies are then used to identify and develop lower-cost and more stable cell materials and components. The improvements resulting from the use of these new cell materials and components are then verified using sealed cells. Results from this program are being used as the basis for establishing new industrial battery development projects that are funded by the United States Advanced Battery Consortium (USABC) and DOE.

In the area of cost reduction, the ATD program focuses on reducing cost at the cell material and component levels. A very detailed battery design model is used to establish these costs for different Li-Ion battery chemistries. The battery design model considers the cost of each material going into the cell, as well as the performance of the cell that uses these materials. Therefore, materials that have extremely high power capabilities over their entire range of state-of-charge will minimize the unusable energy of the cell and thereby reduce the size and capacity of a cell that employs these materials. This is an extremely effective way to reduce materials cost at the cell level.

Materials Research under DOE's Exploratory Research Program

Argonne participates in DOE's BATT program by conducting research on novel anode and cathode materials for use in Li-Ion batteries for transportation applications. Argonne's research is focused on inter-metallic anode materials and structurally-integrated composite cathode materials. The family of structurally-integrated composite cathode materials includes members that operate well under the high-rate conditions needed for HEV applications. Additionally, these cathode materials exhibit much better inherent abuse tolerance characteristics than conventional cathode materials for Li-Ion batteries. Members of this family are being studied under the ATD program, as well as by other organizations worldwide, for their use in HEV batteries.

Collaborative R&D with Industry

Argonne is internationally recognized for its expertise in the area of lithium battery materials R&D. Argonne works with industrial firms on a variety of contracts, some of which are linked to the HEV application. One of the projects directly linked to HEV applications is with EnerDel, a U.S. battery company being funded by the USABC⁄DOE. In this case, the cell chemistry--nano-phase lithium titanate⁄lithium manganese spinel--is a cell chemistry that Argonne studied as part of the ATD program. Argonne developed a new form of nano-phase lithium titanate that makes this a very viable system for use in HEV applications. EnerDel saw Argonne’s data and has teamed with Argonne to develop this system for HEV applications.

May 2008