Electrical Energy Storage Technology

Charge Acceptance

Investigations into the influence of additives on the structure and behavior of lead electrodes in order to improve dynamic charge acceptance of batteries in micro-hybrid vehicle application

  • Joint project
  • Partners: Fraunhofer Institute for Silicate Research ISC, TU Berlin & Ford Research and Advanced Engineering Europe
  • Funding organization: ALABC
  • Project duration: 12/2017 - 05/2019

Objectives and method

The goal of the project was to understand whether testing the dynamic charge acceptance (DCA) at laboratory cell level delivers representative results. To achieve this, two different approaches are utilized. 

In the first approach, small 2 V laboratory test cells with one negative and two positive electrodes are prepared. This approach is called the bottom-up approach, as it starts with paste preparation on laboratory scale. The key aspect of this approach is the usage of tailored carbon additives that are able to adjust the DCA of the electrodes. With the help of these test cells, a better understanding of the DCA in general and with regards to the long-term DCA (after run-in) can be acquired.

In the second approach, commercial 12 V EFB and EFB+C batteries with distinct differences in their DCA performance will be used. This approach is called the top-down approach, because 2 V test cells with reduced numbers of electrodes shall be extracted from those 12 V batteries. This investigation should illustrate how the DCA of the original batteries is affected by changing the number of electrodes as well as by the ratio between the positive active mass, the negative active mass, and the electrolyte.

Objectives

  • How meaningful are DCA tests at laboratory-cell level?
  • How do the size and number of plates in test cells influence the measurement of the DCA?
  • How do carbon additives improve the long-term DCA after run-in?
  • What is the origin of the decline in the DCA during the first several weeks of field or laboratory operation?
  • Is there a correlation between cyclic voltammetry/Tafel testing, impedance spectroscopy and DCA?

Address

Technische Universität Berlin
Electrical Energy Storage Technology
Institute of Energy and Automation Technology
Faculty IV
Office code EMH 2
Einsteinufer 11
D-10587 Berlin

Contact