Rechargeable lithium-ion batteries are promising candidates for building grid-level storage systems because of their high energy and power density, low discharge rate, and decreasing cost. A vital aspect in energy storage planning and operations is to accurately model the aging cost of battery cells, especially in irregular cycling operations. This paper proposes a semi-empirical lithium-ion battery degradation model that assesses battery cell life loss from operating profiles. We formulate the model by combining fundamental theories of battery degradation and our observations in battery aging test results. The model is adaptable to different types of lithium-ion batteries, and methods for tuning the model coefficients based on manufacturer’s data are presented. A cycle-counting method is incorporated to identify stress cycles from irregular operations, allowing the degradation model to be applied to any battery energy storage (BES) applications. The usefulness of this model is demonstrated through an assessment of the degradation that a BES would incur by providing frequency control in the PJM regulation market.

Modeling of Lithium-Ion Battery Degradation for Cell Life Assessment

https://robots.iopscience.iop.org/article/10.1149/2.0411609jes/pdf

Calendar Aging of Lithium-Ion Batteries I. Impact of the Graphite Anode on Capacity Fade

This paper presents an overview on charging strategies for lithium-ion batteries. Moreover, a detailed assessment of charging strategies is performed, based on an extensive experimental study with three different cell types. The experimental results reveal that the impact of charging currents and charging voltages on cycle life can vary markedly among different lithium-ion batteries. In general, the cycle life is influenced more by high charging currents than by high discharging currents. Different boost charging protocols have disclosed that high charging currents can deteriorate cycle life not only at high state of charge (SoC), but also at very low SoC. Our investigations on pulse charging show that lithium-ion cells withstand charging pulses of high current or high voltage without any deterioration in cycle life, when the duration of the pulses remains short and the mean current and voltage values are considerably lower. For pulses of less than 1 s, cycle life has been similar for pulsed and continuous charging with the same mean charging currents and identical cycle depths. This paper also presents the impact of charging currents and charging voltages on capacity utilization, charging time, and efficiency to support the development process of optimized charging protocols for practical applications.

Charging protocols for lithium-ion batteries and their impact on cycle life—An experimental study with different 18650 high-power cells

A review on modeling of electro-chemo-mechanics in lithium-ion batteries

https://iopscience.iop.org/article/10.1149/2.0281914jes/pdf

Review and Performance Comparison of Mechanical-Chemical Degradation Models for Lithium-Ion Batteries

Modeling mechanical degradation in lithium ion batteries during cycling: Solid electrolyte interphase fracture

To draw reliable conclusions about the internal state of a lithium-ion battery or about ageing processes using physico-chemical models, the determination of the correct set of input parameters is crucial. In the first part of this publication, the complete set of material parameters for model parameterization has been determined by experiments for a 7.5 Ah cell produced by Kokam. In this part of the publication, the measured set of parameters is incorporated into a physico-chemical model. Model results are compared to validation test results conducted on the Kokam cell. The influence of current rate and temperature is considered as well as a comparison with pulse tests is shown. It is discussed to which extent material parameters obtained by experimental investigation of laboratory coin cells can be transferred to commercial cells of the same material. The validity of physico-chemical models to describe cells is shown. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0541509jes] All rights reserved.

Parameterization of a Physico-Chemical Model of a Lithium-Ion Battery II. Model Validation

From system layout to the vehicle integration a lot of design steps have to be taken into account regarding high-voltage (HV) batteries for electric vehicles. Electrical performance has to be traded off against mechanical and thermal issues several times during development. Besides the physical setup also the management of the battery system has to be considered and adapted to the chosen system layout, which leads among others to an optimized amount of sensors that are needed to ensure the safety of the system. As especially public transport is a promising sector for electric mobility, technical questions such as the thermal management and cell contacting shall be considered and shown by the example of a battery for a full-electric bus in the pilot-project “Smart Wheels”, supported by the German Ministry of Economics and Technology (BMWi). Within the project the battery system as well as a fast charge concept for the whole day operation of the vehicle were developed and taken into operation. This work aims to give an overview of the full development cycle in the design of a new traction battery including test results of the prototype and solutions for technical questions such as the thermal management.

Izaro Laresgoiti

Papers

Modeling mechanical degradation in lithium ion batteries during cycling: Solid electrolyte interphase fracture

Parameterization of a Physico-Chemical Model of a Lithium-Ion Battery II. Model Validation

HV Traction Battery: From Layout to Realization