Power X-Change - das innovative Akku-System von Einhell (mit Dr. Markus Thannhuber) - Episode 2

I'm Dr. Markus Thannhuber, responsible for quality assurance, technology, and production on the board. Today I want to introduce the heart of the Power Exchange technology platform: the lithium-ion cell used in our power packs. This episode focuses on battery chemistry and electrochemistry, and it may be longer than others. If you prefer a brief overview, see episodes 1 or 3 for battery packs and episode 4 for charging technology. Lithium is an alkali metal with atomic number 3, highly reactive, and its redox potential of -3.04 V allows cell voltages up to 3.6 V—far higher than lead-acid or NiMH cells. This gives lithium cells up to 300% more energy content for tools. The basic principle of a secondary lithium-ion cell involves a reversible redox reaction spatially separated by a separator that only lets lithium ions pass. During discharge, lithium ions move from the graphite anode to the metal oxide cathode, while electrons flow externally. This yields energy. Practical challenges include avoiding metallic lithium due to dendrite growth, using non-aqueous electrolytes to withstand higher voltages, and forming a solid electrolyte interface (SEI) that protects the anode but must remain ion-conductive. Managing the cell's electrochemical metabolism is critical to prevent lithium plating, thermal runaway, or internal shorts. The cell construction involves coating copper and aluminum foils with active materials, attaching tabs, winding into a jelly roll, filling with electrolyte, and forming the SEI. For power tools, we need cells optimized for high current peaks and fast charging, not just high capacity. This requires improving active material distribution, reducing ionic distances, optimizing tab placement and heat management. The cell also acts as a double-layer capacitor to handle instantaneous current surges. Safety features include a current interrupt device, dual pressure relief mechanisms, and a shutdown separator with thermal shutdown pores. We also address cell aging, which is accelerated by higher temperatures and deeper charge states. By using advanced electrolytes and additives, we strengthen the SEI and improve cycle life. The physical robustness of cylindrical cells in metal cans protects against impacts. Power Exchange cells are specifically designed for high-power tool applications, combining fast electrochemistry, excellent dielectric properties, and superior thermal management for maximum operational safety. This concludes episode two; in episode three we will present the Power Exchange battery packs. Thank you for your attention.