Full exam for Electrochemical Energy Conversion and Storage in the Energy Engineering degree programme at Politecnico di Milano. The document covers: EECS – Prof. A. Casalegno – 13th July 2022 1 Standard EECS exam [duration 1 h 40 min] Students who passed TiP reduced number of questions marked with (TiP) [duration 1 h 10 min] To upload (maximum 5 single-side A4 pages – PDF file name MUST BEGIN with person code) Basic Part
Full exam for Electrochemical Energy Conversion and Storage in the Energy Engineering degree programme at Politecnico di Milano. The document covers: EECS – Prof. A. Casalegno – 13th July 2022 1 Standard EECS exam [duration 1 h 40 min] Students who passed TiP reduced number of questions marked with (TiP) [duration 1 h 10 min] To upload (maximum 5 single-side A4 pages – PDF file name MUST BEGIN with person code) Basic Part
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EECS – Prof. A. Casalegno – 13th July 2022 1 Standard EECS exam [duration 1 h 40 min] Students who passed TiP reduced number of questions marked with (TiP) [duration 1 h 10 min] To upload (maximum 5 single-side A4 pages – PDF file name MUST BEGIN with person code) Basic Part (4.5 points per question, minimum score 12) (TiP: 7.5 points) 1. Write the Butler-Volmer kinetics equation for hydrogen oxidation reaction (HOR) 2. Write Faraday’s law for electrolyte and reactants of an alkaline electrolyzer 3. (TiP) Write an example of electrochemical reactions occurring in a Lithium-ion battery and the typical battery voltage range Exercise (TiP) A Li-ion battery with nominal capacity of 50 Ah operates at ambient pressure and temperature, requiring 3.8 V for discharging at SoC=80% and C-rate=2 h-1. Assuming that: 1. Tafel kinetics is valid for both electrodes 2. ion and mass transport effects in electrodes are negligible 3. activities of reactants in charge are close to the value of (1-SoC) 4. electrolyte resistance is equal to 1.8 mΩ 5. transfer coefficients of both electrodes during discharge are equal to 0.5 During charge at C-rate=1 h-1, the voltage reaches the value of 3.8 V, estimate the achieved SoC. Intermediate Part (3 points for each question) (TiP: 5 points) 1. Show how current density equation, derived from Nernst-Plank equation, simplifies in the case of a solid electrolyte with fixed charge 2. (TiP) Depict in the chart DV=f(SoC) a typical discharge curve of a Lithium-ion battery and the curves of DV loss attributed to positive electrode, negative one and electrolyte EECS – Prof. A. Casalegno – 13th July 2022 2 Exercise (TiP) A PEM fuel cell operates at 80°C with pure H2 and air at 0.25 MPa pressure and supplies at 0.65 V a current density equal to 1.7 A/cm2 and…
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