Izdelava in ovrednotenje regenerativnega polnilnika in preizkuševalnika Li-ion baterij

DOMADENIK, SAŠO (author), Humar, Iztok (mentor)

Pri testiranju kapacitete Li-ion baterije, je treba iz baterije odstraniti veliko energije. Odvajanje te energije lahko povzroča težave in omejuje hitrost testiranja. V tem diplomskem delu je prikazano načrtovanje preizkuševalnika, ki uporablja alternativni način praznjenja baterij. Namesto da bi se energija pretvorila v toploto, se z uporabo stikalnega pretvornika prenese v drugo baterijo. Pretvornik je osnovan na topologiji dvosmernega pretvornika navzdol/navzgor. Tako vezje je simetrično in lahko deluje v načinu pretvorbe navzdol, navzgor ali navzdol/navzgor, kar omogoča prenos energije v obe smeri, torej tako polnjenje kot praznjenje. Za krmiljenje preizkuševalnika je uporabljen mikrokrmilnik STM32F401CCU, ki je najbolj poznan po uporabi na cenovno dostopnih razvojnih ploščicah »Blackpill«. Pri ovrednotenju preizkuševalnika je bilo ugotovljeno, da deluje z Li-ion baterijami nazivne napetosti od 3,7 V do 11,1 V in v večini primerov omogoča praznjenje s 5 do 10-krat manj izgubami, v primerjavi s preizkuševalniki z linearnimi bremeni. V načinu delovanja navzdol/navzgor je bil izkoristek manjši, vendar še vedno nad 60 %.

• Language: Slovenian
• Keywords: Li-ion baterija, stikalni pretvornik, kapaciteta baterije, dvosmerni prenos energije
• Work type: Bachelor thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2022
• PID: 20.500.12556/RUL-139584
• COBISS.SI-ID: 120400387
• Publication date in RUL: 05.09.2022

Secondary language

• Language: English
• Title: Design and evaluation of a regenerative Li-ion battery charger and tester

Abstract

When testing the capacity of a Li-ion battery, a large amount of energy must be removed from the battery. The dissipation of this energy can be a problem and can limit the speed of testing. This thesis addresses the design of a battery tester, which uses an alternative discharging method. Instead of converting the energy to heat, it uses a switching converter to transfer the energy into another battery. The converter is based on the bi-directional buck-boost converter topology. Such a circuit is symmetrical and can operate as a buck, boost, or a buck-boost converter, enabling the transfer of energy in both directions, supporting both charging and discharging. For controlling the converter an STM32F401CCU microcontroller is used. It is most known for its use on the cheap and readily available Blackpill development boards. Evaluation of the tester showed that it can operate with Li-ion batteries with a nominal voltage from 3.7 V to 11.1 V and can, in most cases, discharge the battery with 5 to 10 times less losses, compared to a tester using a linear load. When operating in buck/boost mode the efficiency was lower, but still above 60 %.

• Keywords: Li-ion battery, switching converter, battery capacity, bidirectional energy transfer