[1] Tech Univ Clausthal, Res Ctr Energy Storage Technol, Stollen 19A, D-38640 Goslar, Germany
[2] Tech Univ Clausthal, Inst Chem & Electrochem Proc Engn, Leibnizstr 17, D-38678 Clausthal Zellerfeld, Germany
[3] Fraunhofer Inst Telecommun, Heinrich Hertz Inst, Stollen 19H, D-38640 Goslar, Germany
[4] Tech Univ Clausthal, Inst Elect Power Engn & Elect Energy Engn, Leibnizstr 28, D-38678 Clausthal Zellerfeld, Germany