The objective of the proposed work is to develop a high performance, long-lived lead acid battery for a range-extended, hybrid Electric Vehicle (REHEV). The battery design will use horizontal plates and improved conductor structures to provide high power discharge. The design will also incorporate various additives, both conductive and nonconductive, into the positive paste to improve the energy performance of the battery. Two models, the Conductivity Model and the Diffusion Model, have been developed and documented, and we will use them to design cells and predict performance.
The battery development program is divided into three tasks. Task 1 involves the design of the baseline cell. The baseline cell will provide 35 w-hr/kg at the 2-hr. discharge rate, 200 w/kg at 100 percent state of charge, (SOC), and 1000 cycles at 80 percent depth of discharge (DOD). We will use our initial design from Task 1 to help establish a cell development program with battery manufacturers. We will present the initial cell design to different battery manufacturers and work with them to modify the design for their manufacturing processes. We will also use our models to assist the battery manufacturers in developing their baseline cell design. We anticipate that the next phase of this program will be to fabricate and test the baseline cells of the different manufacturers. The baseline cells will also serve as the standard against which the performance of advanced cells will be measured.
The baseline cells, when developed into batteries, will enable the commercial-ization of a REHEV. However, we believe that the specific energy performance of this cell can be greatly improved with the use of different additives. We plan to use a continuous improvement process to increase the specific energy performance of the baseline cells for the various manufacturers.
We will use the Conductivity Model and the Diffusion Model to evaluate the performance of cells having high performance plates. We believe we can increase the energy performance of the baseline cells from 30–35 w/k to 60–65w/kg. In the third task, we will make modifications to the Conductivity Model in order to estimate the cycle life of lead-acid batteries. The information developed in this task will be used to design and model the life of cells in Tasks 1 and 2. In Task 4, we will report our results.