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2022
Journal Article
Title
Comparison of Dynamic Charge Acceptance Tests on Lead-Acid Cells for Carbon Additive Screening
Abstract
Including a certain amount of carbon in the negative active material is currently the state-of-the-art method to improve the dynamic charge acceptance (DCA) of lead-acid batteries. The DCA is a key parameter of batteries used in microhybrid cars where brake energy recuperation is implemented. To find the optimal carbon additive, it is essential to test the carbon both in short-term and long-term tests. This work investigates the long-term and short-term DCA of 2 V, 2.5 Ah lead-acid cells and correlates the results with the external surface area of the carbon. Five different carbons with tailored particle size (27-633 nm) and external surface area (7.1-159.3 m2 g-1) are employed as additives in the negative electrodes. The charge acceptance of cells according to the charge acceptance test 2 (SBA), the DCA (EN) test, and the run-in DCA test (Ford) is increased via an increase in the carbon external surface area. A correlation between the short-term tests and the first week of the run-in DCA test is established for the carbon impact. After several weeks of run-in DCA test, the carbon effect is diminished and only a differentiation between high and low DCA cells is possible.
Author(s)
Bauknecht, Sophia
Electrical Energy Storage Technology Technische Universität Berlin, Berlin, Germany
Karden, Eckhard
Ford Research Advanced Engineering Europe Advanced Power Supply Energy Management 52066 Aachen Germany