Si-air Battery

Si-air Battery: Alkaline cell modelling in MATLAB (Simscape)

Jacob, Nithin (TU Delft Electrical Engineering, Mathematics and Computer Science)

van Swaaij, R.A.C.M.M. (mentor)
Smets, A.H.M. (graduation committee)
Santbergen, R. (graduation committee)
Kelder, E.M. (graduation committee)

Delft University of Technology

Electrical Engineering | Sustainable Energy Technology

Si-air Battery

2020-10-19

Renewable energy sources (RES) such as Solar and Wind energy rely on the availability of natural resources like sunlight in the case of Solar and wind speed in the case of Wind energy generation which is variable in nature. There are periods where there is excess energy production than needed and periods of energy shortage where not enough energy is produced to meet the demand. To mitigate this mismatch, a short term solution is to use batteries in order to store energy at times where energy production is more than the energy demand. This stored energy would be later used at times where energy production is low and meet the energy demand. However, the current battery technology is still novel for this application making it uneconomical when compared to current energy infrastructure of using power plants. The current battery market is held by Li-ion batteries which uses lithium as a raw material which is a rare earth material. In 2009, a battery cell utilizing Si as its anode and air as its cathode was discovered. As this system relies on two of the most abundant elements in the earth's crust which is silicon and oxygen and has much higher theoretical energy density than Li-ion batteries, it has become a growing area of research and development. Battery models are created to simulate battery operations based on empirical formulas and electrochemical reactions taking place in the battery. Development of these models are very critical as they provide results and optimum condition evaluations much faster than physical testing with minimal resources. A battery model for the alkaline Si-air battery which utilizes KOH as the cell electrolyte is developed in Simscape (MATLAB) as part of this thesis. The modelling parameters are also subjected various physical conditions such as varying electrolyte concentration and change in electrode materials and the variation is investigated for model validation to study whether changing physical conditions of the Si-air cell has an effect on the modelling cell parameters. It is supported with experimental results obtained from discharging a fabricated Si-air cell. It was concluded that there are cell parameters which are dependent only on the state of charge (SOC) of the cell and one cell parameter that is a function of both the SOC as well as the discharge profile of the cell. The fabricated Si-air cell gives higher open-circuit potential (OCP) values than what was reported constant 1.4 V in literature which is speculated to be due to the usage of a 99% Aluminum and 1% Silicon (Al:Si) back contact layer. Average OCPs ranging from 1.5 V to 1.45 V which varies due to change in electrolyte (KOH) concentration is achieved. The MATLAB battery block is calibrated to be integrated with energy system models as a Si-air battery.

Battery
Battery technology
Si-air
Metal-air
Alkaline battery
Simulink
Simscape
MATLAB
Battery management system
Silicon

http://resolver.tudelft.nl/uuid:b87e0281-0c18-442b-aacf-65b49f4e0081

Student theses

master thesis

© 2020 Nithin Jacob