Wirkungsgradoptimierung einer Hochstromladeschaltung einer Lithium-Ionen-Zelle

Translated title of the contribution: Efficiency improvement of a high current charging device for a lithium-ion-cell

Herbert Ziegerhofer

Research output: ThesisMaster's Thesis

670 Downloads (Pure)


Nowadays, more and more rechargeable batteries are used in vehicles with electric powertrain. For this reason, batteries with a high capacity, high energy per weight ratio, and high safety level equivalent to a high SOH (State of Health) are necessary. Batteries which have lost more than 20 percent of their original capacity or where the battery pack includes some few deteriorated cells after some longer time of usage must be replaced by new ones. However, these batteries can be reused in applications where high initial capacity is not mandatory, maybe after replacement of deteriorated cells inside the package. The current state of batteries must be tested by charge and discharge cycles in order to decide which battery-cells can be reused. The focus of this master thesis is on the charging cycle of one individual battery-cell with high current by usage of commercial electronic and electrical parts such as operational amplifier and switched-mode power supply (SMPS). Due to the fixed output voltage of the used SMPS which is a low cost ATX power supply unit used in personal computers, a closed-loop control of output-voltage (selectable maximum end of charge voltage) and maximum output current must be implemented. Fundamental parameters (output-voltage, -current and battery-temperature) during charging have to be displayed (set-point-value and actual value), monitored and limited, especially with regard to safety considerations. In case of over-temperature a protective circuit cuts off charging and this event is stored. Further requirements such as best possible efficiency, power-grid friendly behavior (sinusoidal current consumption and reactive power compensation because of active power factor correction) are also provided by the SMPS. The device was designed, assembled and commissioned followed by extensive measurements, especially concerning efficiency measurements in comparison with a charging device containing a linear power dissipation control.
Translated title of the contributionEfficiency improvement of a high current charging device for a lithium-ion-cell
Original languageGerman
  • Weiß, Helmut, Supervisor (internal)
Award date26 Jun 2015
Publication statusPublished - 2015

Bibliographical note

embargoed until null


  • efficiency improvement
  • high current
  • charging device
  • lithium-ion-cell
  • state of health
  • switched-mode power supply
  • closed-loop control
  • set point value
  • actual value
  • monitoring
  • safety considerations
  • protective circuit
  • power-grid friendly
  • active power factor correction
  • linear power dissipation control

Cite this