Suggested Citation:
Burke, Andrew (2009) Performance, Charging, and Second-use Considerations for Lithium Batteries for Plug-in Electric Vehicles. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-09-17

This paper is concerned with batteries for use in plug-in electric vehicles. These vehicles use batteries that store a significant amount (kWh) of energy and thus will offer the possibilities for second-use in utility related applications such as residential and commercial backup systems and solar and wind generation systems. Cell test data are presented for the performance of lithium-ion batteries of several chemistries suitable for use in plug-in vehicles. The energy density of cells using NiCo (nickelate) in the positive electrode have the highest energy density being in the range of 100-170 Wh/kg. Cells using iron phosphate in the positive have energy density between 80-110 Wh/kg and those using lithium titanate oxide in the negative electrode can have energy density between 60-70 Wh/kg. Tests were performed for charging rates between 1C and 6C. The test results indicate that both iron phosphate and titanate oxide battery chemistries can be fast charged. However, the fast charge capability of the titanate oxide chemistry is superior to that of the iron phosphate chemistry both with respect to temperature rise during charging and the Ah capacity retention for charging up to the maximum voltage without taper.

There are a number of possible second-use applications. Some of these applications are closely linked to utility operations and others are connected to commercial and residential end-users. Since the energy storage and power requirements for the end-user applications are comparable to those of the original vehicle applications and would require only minor reconfiguring of the packs, these applications are well suited for second-use. The applications closely related to utility operations do not seem well suited for second-use. Those applications require MW power and MWh of energy storage which are orders of magnitude larger than that of the vehicle applications. The primary barrier to implementation of the second-use is demonstrating the economic viability of the reuse of the batteries in terms of the cost of the batteries to the second owners and a guarantee that the used batteries would have satisfactory calendar and cycle life.