Determination of the entropy change profile of a cylindrical lithium-ion battery by heat flux measurements

By K.A. Murashko and A.V. Mityakov and V.Y. Mityakov and S.Z. Sapozhnikov and J. Jokiniemi and J. Pyrh
Published in Journal of Power Sources NULL 2016

Abstract

The popularity of lithium-ion (Li-ion) batteries has increased over the recent years. Because of the strong dependence of the Li-ion battery operation characteristics on temperature, heat generation in the battery has to be taken into account. The entropy change of a Li-ion battery has a significant influence on heat generation, especially at a low C-rate current. Therefore, it is necessary to consider the entropy change profile in the estimation of heat generation. In the paper, a method to determine the entropy change (?S) profile by heat flux measurements of a cylindrical Li-ion cell is proposed. The method allows simultaneous measurements of the thermal diffusivity and ?S of the cylindrical cell. The thermal diffusivity and ?S measurements are carried out by a gradient heat flux sensor (GHFS). The comparison between the ?S profile determined by the \GHFS\ method with that obtained using a standard potentiometric method clearly shows that the entropy change measurements could be made by using a GHFS. Even though the uncertainty of the reported method is higher than that of the potentiometric method, a significant decrease in the experiment time compared with the potentiometric method is a major advantage of this method.

Read Article » Back