|A123Systems scalable prismatic module is reconfigurable for applications ranging from 1 kWh to more than 100 kWh. Source: A123Systems. Click to enlarge.|
At the Department of Energy (DOE) Annual Merit Review for the Hydrogen and Vehicle Technologies Programs, A123Systems co-founder Ric Fulop described the progress the company has made with two DOE-funded projects, one on high-power hybrid batteries, the other on plug-in hybrid battery development.
A123Systems, which began by manufacturing cylindrical format cells, is developing a portfolio of prismatic automotive cells funded through two USABC 50:50 cost share programs. The emerging prismatic lineup includes a 20Ah energy cell for plug-in hybrid and electric vehicles, with a targeted start of production (SOP) of 2009/2010; and 4Ah, 6Ah and 8Ah power cells for hybrids, with vehicle SOP of 2011/2012.
At the same time, A123Systems has continued to refine its cylindrical cells, with the second-generation of the cell (Gen-1, based on a Gen-0 start) 32113 cell entering high-volume production with a major European OEM later this year. The Gen-1 cell has a capacity of 3.8 Ah. A coming Gen-2 cell, which uses a higher power and lower-cost electrode design, will offer 4.4-4.6 Ah of capacity, and is targeted for mass production start in 2010.
|A123Systems prismatic power cells. Source: A123Systems. Click to enlarge.|
The 32113 cell, while offering good price performance, offers only average power density. For premium power density applications, A123Systems is focusing on prismatic cells.
The three new prismatic power cells—4Ah, 6Ah, 8Ah—are targeting at mild, full and heavy-duty hybrid electric vehicles, respectively. Power density ranges from 4,590 W/kg for the 4Ah cell to 5,300 W/kg for the 8 Ah cell.
|Price/performance and power of HEV cells. Source: A123Systems. Click to enlarge.|
The new prismatic cells offer an significant improvement in cost per kW as well almost doubling the power density compared to the Gen-2 32113 cell.
A123Systems began work on its USABC-funded plug-in hybrid program in March 2008. The 20 Ah cell is designed for plug-in and extended-range EV applications.
The prismatic cell features an increased energy density through new anode and cell designs. New materials provide increased cycle life and energy density. On the cathode side, A123Systems has scaled up its efforts to reduce costs through improved and more efficient processes, and continues to expand cathode development to improve both capacity and energy.
At the cell level, the energy density (Wh/kg) of the new 20Ah cell is 50% greater than that of the old 26650 cylindrical cell (from 2007), while the module level energy density increased by 30%.
|Scalable pack architecture allows common parts to be used for different pack designs. Source: A123Systems. Click to enlarge.|
As part of the project, A123Systems is developing a flexible, scalable modular design and architecture. The pack can be liquid- or air-cooled, and has integrated electronics.
Fulop said the company had multiple commercial design wins for the 20Ah cell with major North American and European OEMS. Commercial mass production for the cell is due to start in 2010.