Second-life applications of batteries
The business case for electric vehicles depends heavily on investment and the performance of the batteries used. It is expected that, for some years to come, electric vehicles will need subsidizing to get them into the market. The batteries are too expensive for electric vehicles to secure a competitive market position in the short term.
To improve the business case for electric vehicles, the total cost of ownership needs to be reduced and the battery performance needs to be enhanced. The total cost of ownership can be brought down by lowering the initial purchase cost and/or by increasing the value of a used battery, e.g., by finding ways of reusing them (second-life applications).
During its time as an electric vehicle’s power source, a battery will lose some of its capacity. As a result, the range of the vehicle (how far it can go between charges) will decline. Drivers will regard this as a drawback and will ultimately be inclined to replace the battery. This will mark the end of the battery’s life as a vehicle power source. However, although the battery may no longer be good enough for continued use in an electric vehicle, it will still be able to accept a charge and to discharge electricity. So it may as well still be good enough for other applications, such as grid-connected storage.
DNV KEMA has been commissioned to look into potential second-life applications for EV batteries. The focus of the project will be on the reuse of EV batteries in the distribution grid. DNV KEMA is investigating the technical requirements for and economic viability of this application.
The technical evaluation involves exploring the requirements for and tests needed to evaluate batteries after use in vehicles. DNV KEMA is also studying the specifications of the necessary power electronics. In addition, DNV KEMA is investigating the opportunities for storage in the grid. Finally, DNV KEMA is evaluating whether second-life batteries meet the requirements for the gridconnected storage systems.
DNV KEMA has developed a model (PLATOS) to optimize the use of storage systems in a particular distribution grid. The specifications for second-life batteries can be determined and put into this model, thus generating more detailed information relevant to the business case for a particular second-life application. On the basis of the results, DNV KEMA will compare the use of a second-life battery with the use of a new one.
The project will result in a technical and economic feasibility report on re-using EV batteries for grid-connected storage. This will answer questions like: what kind of testing is needed to characterize the battery before use in a second-life application? Is it advantageous to disassemble the whole battery and re-use its constituent cells, or is it better to keep and reuse the batteries intact? What kind of power electronics is necessary to control operation of the storage system? How does a second-life battery storage system compare with a new battery system?
EOS-LT NEO Program (Energy Research Subsidy, Long-Term, New Energy Development)
Duration: January 2010 – December 2010