**Contents**


## **About the Special Issue Editor**

**Julia Kowal** studied Electrical Engineering and Information Technology at RWTH Aachen University. She also conducted her Ph.D. in Electrical Engineering here within the Institute for Power Electronics and Electrical Drives (ISEA), Electrochemical Energy Conversion, and Storage Systems on the topic of "Spatially Resolved Impedance of Nonlinear Inhomogeneous Devices—Using the Example of Lead-Acid Batteries". After finishing her Ph.D., she worked as Chief Engineer and Head of the department "Modelling, Analytics and Lifetime Prediction", Electrochemical Energy Conversion and Storage Systems, ISEA, RWTH Aachen University. She has served as Professor of Electrical Energy Storage Technology at TU Berlin since her appointment in 2014. Her research focuses on the characterization and modelling of different battery technologies, such as lithium-ion batteries, lead–acid batteries, and metal–air batteries with the aim of lifetime prediction and optimized operation as well as state determination.

## **Preface to "Lifetime Prediction and Simulation Models of Dif ¢ȱȱȄ**

Energy storage is one of the most important enablers for the transformation to a sustainable energy supply with greater mobility. For vehicles, but also for many stationary applications, the batteries used for energy storage are very flexible but also have a rather limited lifetime compared to other storage principles. Many different battery technologies exist which, in part, show a similar aging behavior, but each of which mostly has their own characteristic aging processes. Other storage principles such as supercaps, fuel cell/electrolyzer/storage systems, or thermal storage also show declining performance with time. To develop reliable systems and facilitate cost calculations, it is therefore necessary to understand the aging processes as well as its influencing factors. This Special Issue is a collection of articles that collectively address the following questions:


The articles deal with different topics in the following fields:


**Julia Kowal** *Special Issue Editor*

## *Article* **Study of a Li-Ion Cell Kinetics in Five Regions to Predict Li Plating Using a Pseudo Two-Dimensional Model**

#### **Sanaz Momeni Boroujeni \* and Kai Peter Birke**

Electrical Energy Storage Systems, Institute for Photovoltaics, University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany; Peter.Birke@ipv.uni-stuttgart.de

**\*** Correspondence: sanaz.momeni@ipv.uni-stuttgart.de

Received: 17 October 2019; Accepted: 7 November 2019 ; Published: 14 November 2019

**Abstract:** Detecting or predicting lithium plating in Li-ion cells and subsequently suppressing or preventing it have been the aim of many researches as it directly contributes to the aging, safety, and life-time of the cell. Although abundant influencing parameters on lithium deposition are already known, more information is still needed in order to predict this phenomenon and prevent it in time. It is observed that balancing in a Li-ion cell can play an important role in controlling lithium plating. In this work, five regions are defined with the intention of covering all the zones participating in the charge transfer from one electrode to the other during cell cycling. We employ a pseudo two-dimensional (P2D) cell model including two irreversible side reactions of solid electrolyte interface (SEI) formation and lithium plating (Li-P) as the anode aging mechanisms. With the help of simulated data and the Nernst–Einstein relation, ionic conductivities of the regions are calculated separately. Calculation results show that by aging the cell, more deviation between ionic conductivities of cathode and anode takes place which leads to the start of Li plating.

**Keywords:** li-ion cells; lithium plating; kinetic balancing; ionic conductivity; modeling
