DESIGN OF BATTERY PACKS: STRATEGIES FOR HIGH ENERGY DENSITY, RANGE

Battery design continues to pose challenges for the automotive industry. The requirements are specific for each vehicle, and safety requirements are considerable. A proof of concept from Lion Smart shows that the use of standard cylindrical cells packed closely together is also suitable for vehicles in series production. According to studies, the round cell offers the best energy density at low cost. A cooling and extinguishing concept combined with wireless cell monitoring ensures high performance and safety.

OPPORTUNITIES BY INTELLIGENT DESIGN

In terms of battery development, Europe has now fallen behind. The opportunities in the field of e-mobility now lie above all in the intelligent design of battery packs. In this environment, many manufacturers have oriented themselves so far on the available space and to add the most value possible. This has resulted in formats such as prismatic cells or new pouch formats for the automotive sector. However, they cannot be flexibly integrated and the individual design also creates dependencies on the individual cell manufacturer.

In addition, experience currently shows that the performance specified by the competition in terms of fast charging capability, range and consumption can often not be achieved with these formats. The start-up Lion Smart, a fully-owned subsidiary of Lion E-Mobility AG, is taking a different path that could open up a new scope for automotive developers. Similar to Tesla, the leading manufacturer in the development of electric cars, the research-based start-up has focused on small round cells in its light battery concept.

The availability of multiple cell producers for standard cells does not lead to a dependency on individual cell manufacturers, as it is the case with other battery formats. According to a study by the Fraunhofer Battery Alliance, the most important cell formats are 18650 (currently cost leader in the market) and 21700 (will achieve the greatest cost advantages in 2025). Both formats are therefore leading in terms of energy density [1]. In the light battery concept, both formats can be used. There will be no real standardisation of battery modules and packs in the automotive industry, because larger vehicles require a higher voltage for which the cell block must be designed, which would be oversized for smaller cars. Therefore, a commodity cell that can be handled flexibly is likely to be a realistic step towards standardisation.