In the testing and simulation arena, the more elaborate the information is, the more useful it is. Which underscores why specific tidbits about a given battery pack's voltage, current, energy, power, as well as other life-cycle details are immensely important to the engineers involved in developing hybrid-electric vehicles (HEVs), plug-in hybrid-electric vehicles (PHEVs), and electric vehicles (EVs).
"Having exact information—like the communication between the hybrid controller, the battery management system, and the motor/generator controllers—enables us to develop and verify functionality that is distributed across several components, including the motor/generator and the battery," said Karina Morley, Ricardo's Global Vice President of Controls & Electronics, and the person in charge of Ricardo's soon to be completed 2800-ft² (260-m²) Battery System Development Center in Van Buren Township, MI.
Ricardo's development environment, representing an approximately $2 million investment, features hardware-in-the-loop systems, high-voltage instrumentation, and high-capacity EV, HEV, and PHEV-capable battery cyclers supplied by AeroVironment. The AV-900 and ABC-150 battery cyclers "precisely charge and discharge a battery pack and monitor battery performance throughout various simulations. For instance, we can equip a testing chamber to simulate a battery pack operating under a specific driving cycle and in varying environmental conditions—from extreme cold to high heat. The data from a particular simulation run can be analyzed in terms of battery cell performance, balancing, thermal management, and other specific operational details," said Morley.
In addition to developing battery management systems, Ricardo's battery center also can serve as the test and simulation venue for developing untested battery chemistries. "We can assist OEMs and Tier 1 suppliers with the evaluation and development of new battery chemistries and designs prior to integration into a vehicle. It is important to be able to determine any potential flaw areas up front so that modifications can be made prior to the final design, meaning before actual vehicle testing. Once a battery-pack design is verified in Ricardo's safe, simulated environment, the battery system can be integrated and further developed on a vehicle in Ricardo's adjoining garage facility," said Morley.
Industry experts point out that as much as half of the development cost of a battery system relates to the robust integration of the battery cells into the packs. "We will be able to evaluate the entire system and help design the entire system for the best overall cost at the project's outset. That means we will help customers reduce battery-pack manufacturing costs as well as optimize the system as it relates to component selection, structural design, instrumentation, and thermal design," Morley said.
Battery life, safety, and the performance documentation of new chemistries are also on the focal point scorecard. "We will be evaluating and defining an appropriate charge cycle for longer battery life. We will also be evaluating the control system for the pack as well as the system impacts by introducing faults. We also will be evaluating all the electrical and thermal aspects of the system. And, because there are so many different chemistries available, we will be evaluating cells and packs over different conditions and documenting the performance of the cell and control software throughout those conditions," said Morley.
The center's first chamber was slated to go online in the fall of 2008 with an expected staff of more than 30 specialists. Ricardo representatives are in discussions with several OEMS and suppliers. "These projects vary from battery management system development to battery-pack design and development," said Morley, who adds that Ricardo's track record in the HEV, PHEV, and EV arena includes more than 30 projects. "We plan to enhance and expand the center in the course of our future research programs for HEV, PHEV, EV, fuel-cell, and clean-energy markets."