Peukert Revisited– Critical Appraisal and Need for Modification for Lithium-ion Batteries

The Peukert relationship was originally introduced in 1897 for lead-acid batteries and defines one of the most common parameters for battery performance evaluation. This article assesses its application for lithium-ion batteries. From the performed analysis, we can conclude that the Peukert relationship is suitable in a narrow working range such as limited current range and almost constant working temperature. Taking into account however that lithium-ion traction batteries in battery electric vehicle applications operate in strongly variable conditions, a novel relationship has been developed, allowing to describe the discharge capacity of lithium-ion batteries more accurately than the Peukert relationship. The proposed new relationship has been derived based on comprehensive experimental analysis of the parameters that affects the battery discharge capacity and can be implemented in battery mathematical models.