White Paper: Evaluation of Cell Balancing

 

This white paper addresses the topic of cell balancing, especially how balancing strategies can be evaluated regarding their specified goal. First, the actual need for cell balancing is discussed. Subsequently, different balancing goals are defined, depending on the energy storage application. Finally, a balancing strategy is derived, which is suitable for most applications.

Other deliverables can be found and downloaded from Results / Deliverables page this website.

White Paper: Balancing – What vs How

In this white paper we address a topic that is often given too little attention, when discussing balancing. Most scientific papers on this topic deal with different electrical schemes to maximize the balancing current. However, another important aspect of balancing is deciding which current to apply to which cell: this is the so-called balancing strategy. We will explain that the balancing strategy is equally important as the electrical setup and smart combinations of both lead to the optimal balancing solution. To get there, this paper is divided into three chapters. The first one discusses the reason for balancing. The second chapter then gives an overview of possible active balancing circuits and is followed by the third chapter, which presents possible balancing strategies for the different circuits.

Other deliverables can be found and downloaded from Results / Deliverables page this website.

Report on Electrochemical Cell Model

The report summarizes the activities and achievements of work package (WP) 1 regarding the “Cell level detailed modelling” task (Task 1.1). Over the first two years in the EVERLASTING project, different experimental methods were applied on electrode/electrolyte and cell level of the INR18650-MJ1 lithium-ion cell, which is the project cell of the EVERLASTING project. The experimental part is used to parameterize and validate the modelling and simulation part using different thermal-electrochemical models for lithium-ion batteries. The results of the cell level detailed modelling show accurate prediction of the cell’s behaviour under various charge and discharge scenarios, cyclic and calendric aging as well as under different applied cooling strategies and ambient temperature conditions. The report is mainly based on the related publication [1] in the Journal of Power Sources  and the published data repository [2] at the TU Delft (i.e. Research Data Center).  The publications are available under the following DOIs:

Research Paper: https://doi.org/10.1016/j.jpowsour.2018.11.043
Data Repository: https://doi.org/10.4121/uuid:e8735cd2-e478-4db5-80bc-b5051961a0ab

Other deliverables can be found and downloaded from Results / Deliverables page this website.

White Paper: Cell Testing and Estimation of SOH

In this white paper we will discuss SoH estimation and the information gained through cell testing.
We start from the definition of SoH, elaborate on the types of ageing and the cell tests that arepe rformed within EVERLASTING. Finally, we discuss SOH algorithms and the need for SOH prediction.

Other deliverables can be found and downloaded from Results / Deliverables page this website.

New white paper: Definition of SOH

In this white paper  different possible definitions of State of Health (SoH) are discussed. In general, the SoH is a measure for the health of the battery. Depending on the application, the demands asked from the battery can vary. Does the health only involve the capacity that can be delivered or does it also take into account the internal resistance? We will also introduce some possible direct measurement approaches. Furthermore we will deal with how to communicate SoH in a clear and consistent way to the user.

Other deliverables can be found and downloaded from Results / Deliverables page this website.

New Set of Deliverable Reports

A new set of public deliverable reports of the EVERLASTING project has been published:

These deliverables can be found on and downloaded from Results / Deliverables page this website.