“It was a discussion between all the members of the project.”

“It is a special concept,” Stefan Doczy explains, technician at Samsung SDI Battery Systems. Samsung develops the high voltage battery that is used in the hybrid DAF heavy duty truck. Normally a battery for a hybrid vehicle is a single, individual unit. Instead, the ECOCHAMPS battery is modular and can be stacked. Stefan: “You can stack 3, 4 or 5 battery modules between the bottom part of the housing, and the top part that has all the connectors.” Within each module the cells are partially in series and partially in parallel. The advantage is that the total energy content can be increased while the output voltage and the connectors can stay the same. “And if we can keep the electronics and sensors the same for each module, the cost per unit will be significantly lower. To design a component for only 200 or 500 trucks is too expensive. Now parts can be exchanged.”

However, such a solution comes with its own challenges. “Putting the cells in parallel takes more space in the module,” Stefan explains. Besides, it makes the communication between the hybrid controller and the battery management unit much more complex. “There are several signals we can work with, but for every vehicle there are power prediction values. Do you need to predict the power over the next 2 second? Or the next 20 seconds? Or continuously?”

The answer to these questions came from the discussions in the ECOCHAMPS project. “It was a discussion between all the members of the project. Is it the power we need to predict? Or the current?” It was helpful to see the point of view of the different OEMs. “In my opinion it is necessary to have these discussions,” Stefan says. We have them in the ECOCHAMPS project, but we need to have such discussions outside the project too.”

The demonstrator battery already passed the mechanical, electrical and environmental tests. Jürgen Fabian, project lead: “I am curious to see how the battery holds up during the vehicle integration phase, and we are now fine-tuning at vehicle level. Of course, the battery has to be fully operational before April 2018.”