ESCALATE recently spoke with Florian Pampel, who works as Research Associate at the RWTH Chair of Thermodynamics of Mobile Energy Conversion Systems, and a colleague of Kai Franke, who previously shared his insights as part of the RWTH interview series.
Please describe your research to a wider stakeholder audience and highlight innovative aspects.
Our activities in battery concept development relate to identifying the most suitable battery configuration for a specific application with defined performance requirements and an available installation space. This includes cell selection, electrical interconnection, geometric arrangement, but also the design of the electrical and electronic systems components, and the definition of design parameters for the housing design, including wall thicknesses, gaps and manufacturing processes.
The research ambitions initially focus on the software-supported handling of a larger number of battery layouts and subsequently on the most extensive possible systematic evaluation of the battery concepts under consideration based on specific criteria, including performance capability and expected LCA results. The challenges arise due to the limited data available in the course of concept planning in the very early project phase.
All battery system components, including passive components in addition to the cells and the active and passive materials within the cell, are also recorded, and expected cell specification data is derived. In this way, it is investigated how well a battery concept can fulfill the load profile of an application.
What is the connection with the ESCALATE project? How do you benefit from the project, and what synergies exist?
Some of these piloted trucks in ESCALATE are all-electric trucks, such as a refrigerated truck designed for both long-distance and local distribution operations requiring modular battery systems that ensure optimal energy storage and utilisation. With this, ESCALATE provides a demanding application with typical challenges that are relevant today.
As part of this process, the electrical requirements and the existing installation spaces of the pilot were first analysed. In consultation with the OEMs, requirements for mechanical integrity were also defined, allowing their valuable experience to be incorporated into the component design.
The design parameters of the thermal system could be coordinated with the electrical and thermal modelling for a battery concept that complies with the required load profiles. In this way, the concept development for the ESCALATE pilots as a whole represents a suitable application example for developing and applying the design method.
With your expertise and the perspective of your research, where do you currently see the biggest challenge in a large-scale deployment of zero-emission trucks?
There are many challenges for the large-scale use of zero-emission trucks, many of which can be solved with battery electric drives. Megawatt charging is technically demanding, but it is a realistic solution with an appropriate cell technology that offers good power density and an efficient thermal system at the system level. The loss of transport weight and volume can and is already being partially mitigated with legislative adjustments. TCO has not yet been fully clarified, but aspects such as low maintenance costs and energy costs compared to fossil fuels are in favour of battery-electric trucks. In terms of LCA, the production of battery storage consumes a high amount of energy and resources and, depending on the size of the battery, a break-even point compared to a diesel drive is only reached after a noteworthy mileage. However, there are promising approaches in the selection of active materials, production processes and recycling to continuously improve the environmental impact.
The most challenging aspect in terms of implementation timescale from my perspective is therefore the establishment of the charging infrastructure. This is already demanding for passenger cars and will require further time and investment, but a significantly higher order of magnitude for trucks. Nowadays, the space required at highway service stations for trucks taking a break is already critical. In a zero-emission scenario with battery electric vehicles, these trucks would all have to be additionally charged overnight.
What do you think could be the impact (or lack thereof) of projects like ESCALATE on the promotion of zHGV technology/solutions?
A project like ESCALATE offers numerous opportunities for researchers, since innovative concepts, modelling and designs can be created and tested on the physical prototypes of the pilots to demonstrate their feasibility. Thus, the project makes a valuable contribution to identifying, demonstrating and later establishing such solutions, which can improve both the technical maturity and the acceptance and cost competitiveness of electrified drives in heavy-duty vehicles. Especially thanks to the high degree of standardisation and modularisation in the battery concept, it is very promising that the results of ESCALATE can also be transferred and scaled to other applications and other designs.
Which parameters for the LCA calculations are too detailed or too challenging to calculate and, therefore, should be disregarded to avoid an unnecessarily complex system?
As part of the lifecycle inventory (LCI), all processes and material flows that contribute to the desired battery system are collected. In the impact analysis of a battery pack from the system level via the cells to the internal composition of the cells, the active material of the two electrodes has the greatest contribution to the results. For this reason, the life cycle inventory must focus in particular on the electrode configuration, including the selection and proportion of active material and electrode design with coating thickness, mass loading, porosity, etc. Continuing at the cell level, the design parameters relating to the electrode stacking or winding and the cell housing, as well as the energy consumption in the process steps, should be available as precisely as possible. Knowledge of the production site and thus the energy mix for electrical and thermal energy, as well as the transportation routes, is also essential here. This is commonly described as the foreground system, and case-specific data is required here.
On the other hand, there is the background system, which includes other system components in addition to the battery cells and possibly the battery housing, but also passive materials within a battery cell, such as the conductive carbon black, the binder, the separator, the cell insulation, etc. These components only make a minor contribution to the environmental impact. These components only make a minor contribution to the environmental impact, so it makes sense to use average data from LCI databases here to avoid an unnecessarily complex system.