scholarly journals Lifetime and Aging Degradation Prognostics for Lithium-ion Battery Packs Based on a Cell to Pack Method

2022 ◽  
Vol 35 (1) ◽  
Author(s):  
Yunhong Che ◽  
Zhongwei Deng ◽  
Xiaolin Tang ◽  
Xianke Lin ◽  
Xianghong Nie ◽  
...  
Keyword(s):  
Deep Learning ◽  
Lithium Ion ◽  
Fine Tuning ◽  
Battery Pack ◽  
Discharge Process ◽  
Prediction Errors ◽  
Target Domain ◽  
Battery Cell ◽  
Battery Packs ◽  
Battery Cells

AbstractAging diagnosis of batteries is essential to ensure that the energy storage systems operate within a safe region. This paper proposes a novel cell to pack health and lifetime prognostics method based on the combination of transferred deep learning and Gaussian process regression. General health indicators are extracted from the partial discharge process. The sequential degradation model of the health indicator is developed based on a deep learning framework and is migrated for the battery pack degradation prediction. The future degraded capacities of both battery pack and each battery cell are probabilistically predicted to provide a comprehensive lifetime prognostic. Besides, only a few separate battery cells in the source domain and early data of battery packs in the target domain are needed for model construction. Experimental results show that the lifetime prediction errors are less than 25 cycles for the battery pack, even with only 50 cycles for model fine-tuning, which can save about 90% time for the aging experiment. Thus, it largely reduces the time and labor for battery pack investigation. The predicted capacity trends of the battery cells connected in the battery pack accurately reflect the actual degradation of each battery cell, which can reveal the weakest cell for maintenance in advance.

Self-Balancing by Design in Hybrid Electrochemical Battery Packs

2018 ◽  
Author(s):  
Nur Adilah Aljunid ◽  
Michelle A. K. Denlinger ◽  
Hosam K. Fathy
Keyword(s):  
Feedback Loop ◽  
Lithium Ion ◽  
Battery Pack ◽  
Hybrid Cells ◽  
Battery Cell ◽  
Battery Packs ◽  
Li Ion ◽  
Electrochemical Battery ◽  
Novel Concept ◽  
Physics Based Simulation

This paper explores the novel concept that a hybrid battery pack containing both lithium-ion (Li-ion) and vanadium redox flow (VRF) cells can self-balance automatically, by design. The proposed hybrid pack connects the Li-ion and VRF cells in parallel to form “hybrid cells”, then connects these hybrid cells into series strings. The basic idea is to exploit the recirculation and mixing of the VRF electrolytes to establish an internal feedback loop. This feedback loop attenuates state of charge (SOC) imbalances in both the VRF battery and the lithium-ion cells connected to it. This self-balancing occurs automatically, by design. This stands in sharp contrast to today’s battery pack balancing approaches, all of which require either (passive/active) power electronics or an external photovoltaic source to balance battery cell SOCs. The paper demonstrates this self-balancing property using a physics-based simulation of the proposed hybrid pack. To the best of the authors’ knowledge, this work represents the first report in the literature of self-balancing “by design” in electrochemical battery packs.

scholarly journals Run to Failure: Aging of Commercial Battery Cells beyond Their End of Life

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1858
Author(s):  
Andreas Ziegler ◽  
David Oeser ◽  
Thiemo Hein ◽  
Daniel Montesinos-Miracle ◽  
Ansgar Ackva
Keyword(s):  
Computed Tomography ◽  
Single Cells ◽  
Lithium Ion ◽  
Constant Load ◽  
Internal Resistance ◽  
Battery Pack ◽  
X Rays ◽  
Battery Cell ◽  
Jelly Roll ◽  
Battery Cells

The aim of this work is to age commercial battery cells far beyond their expected lifetime. There is a gap in the literature regarding run to failure tests of lithium-ion batteries that this work intends to address. Therefore, twenty new Samsung ICR18650-26F cells were aged as a battery pack in a run to failure test. Aging took place with a constant load current and a constant charge current to accelerate capacity decrease. Important aging parameters such as capacity and internal resistance were measured at each cycle to monitor their development. The end of the test was initiated by the explosion of a single battery cell, after which the battery pack was disassembled and all parameters of the still intact single cells were measured. The distribution of all measured capacities and internal resistances is displayed graphically. This clearly shows the influence of the exploded cell on the cells in its immediate vicinity. Selected cells from this area of the battery were subjected to computed tomography (CT) to detect internal defects. The X-rays taken with computed tomography showed clear damage within the jelly roll, as well as the triggered safety mechanisms.

scholarly journals Research on Key Technologies for Improving the Electro catalytic Performance and Physical Properties of Lithium Batteries in Electric Vehicles

2021 ◽  
Vol 2083 (2) ◽  
pp. 022071
Author(s):  
Qingyuan Fang
Keyword(s):  
Temperature Field ◽  
Heat Generation ◽  
Lithium Battery ◽  
Heat Dissipation ◽  
Lithium Ion ◽  
Catalytic Performance ◽  
Performance Model ◽  
Battery Pack ◽  
Discharge Process ◽  
Battery Cell

Abstract Aiming at the uneven heat generation in various parts of the electric vehicle lithium battery pack during the discharge process, the heat generation mechanism is studied, and the lithium battery catalytic performance model is established to obtain the current density and heat generation rate distribution law of the lithium battery cell on the cell. The thermal model can simulate the thermal behavior of the battery under application conditions. Study the laws of battery heat production, heat transfer, and heat dissipation, and calculate the temperature changes inside and on the battery and the temperature field information in real time to provide a basis for the design and optimization of the battery and battery pack thermal management system. The simulation results show that the established model can predict the heating distribution and temperature field of the internal layered structure of the lithium-ion battery, which is helpful for the subsequent analysis of key influencing factors.

Thermal Analysis and Parametric Investigation of PCM-Air Cooled Lithium Ion Battery Pack

2021 ◽  
Author(s):  
Goker Turkakar
Keyword(s):  
Thermal Analyses ◽  
Lithium Ion ◽  
Battery Pack ◽  
Hydrodynamic Effect ◽  
Discharge Process ◽  
Pumping Power ◽  
Battery Cell ◽  
Parametric Investigation ◽  
Volume Method ◽  
Change Material

Abstract A parametric analysis has been conducted for Phase Change Material-Air cooled battery pack. The system is composed of 26650 lithium-ion LiFePO4 batteries enclosed by PCM. 1-D thermal model for the PCM domain is developed using the Enthalpy method. The finite volume method is employed to solve the energy equation for both cell and PCM domain. The developed computational algorithm has been validated as a result of the simulations for the same conditions with the literature. The discharge process of the batteries has been investigated for 2C, 3C, and 5C rates. Thermal analyses have been performed for passive (natural convection) and active cooling (forced convection). It is aimed to keep the temperature of the battery cell under critical levels. A parametric investigation for crucial parameters like; PCM layer thickness, the thermal conductivity of the PCM, the arrangement of the batteries has been performed. Simulations have been conducted for the constant air velocity and the pumping power. Thanks to the constant pumping power analysis, thermally best-performing configuration has been sought by eliminating the hydrodynamic effect.

Application of the MSMD Framework in the Simulation of Battery Packs

2014 ◽  
Author(s):  
Genong Li ◽  
Shaoping Li ◽  
Jing Cao
Keyword(s):  
Thermal Management ◽  
Lithium Ion ◽  
Power Input ◽  
Battery Pack ◽  
Battery Cell ◽  
Simulation Tools ◽  
Thermal Management System ◽  
Battery Packs ◽  
In Series ◽  
Cell Simulation

Lithium-ion battery has been widely used in electric vehicles (EVs). Battery’s performance, life and safety are of great engineering importance. Using simulation tools, battery’s electric performance and thermal behavior can be computed to provide useful information in the design of a battery pack and its thermal management system. The muti-scale muti-dimensional (MSMD) methodology has been proven to be very effective in the simulation of battery at the battery’s geometry dimension scale. The method has been demonstrated in the literature for a single battery cell simulation. However, in the EV applications, battery packs where individual battery is connected in series and/or parallel are often used to provide the required power input during a real driving cycle. In this paper the MSMD methodology is extended to the battery pack simulation.

scholarly journals Calibration Optimization Methodology for Lithium-Ion Battery Pack Model for Electric Vehicles in Mining Applications

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3532 ◽  
Author(s):  
Majid Astaneh ◽  
Jelena Andric ◽  
Lennart Löfdahl ◽  
Dario Maggiolo ◽  
Peter Stopp ◽  
...  
Keyword(s):  
Electric Vehicles ◽  
Large Scale ◽  
Lithium Ion ◽  
Operating Conditions ◽  
Battery Pack ◽  
Li Ion Battery ◽  
Battery Packs ◽  
Li Ion ◽  
Optimization Methodology ◽  
Battery Cells

Large-scale introduction of electric vehicles (EVs) to the market sets outstanding requirements for battery performance to extend vehicle driving range, prolong battery service life, and reduce battery costs. There is a growing need to accurately and robustly model the performance of both individual cells and their aggregated behavior when integrated into battery packs. This paper presents a novel methodology for Lithium-ion (Li-ion) battery pack simulations under actual operating conditions of an electric mining vehicle. The validated electrochemical-thermal models of Li-ion battery cells are scaled up into battery modules to emulate cell-to-cell variations within the battery pack while considering the random variability of battery cells, as well as electrical topology and thermal management of the pack. The performance of the battery pack model is evaluated using transient experimental data for the pack operating conditions within the mining environment. The simulation results show that the relative root mean square error for the voltage prediction is 0.7–1.7% and for the battery pack temperature 2–12%. The proposed methodology is general and it can be applied to other battery chemistries and electric vehicle types to perform multi-objective optimization to predict the performance of large battery packs.

scholarly journals Effect of dynamic loads and vibrations on lithium-ion batteries

2021 ◽  
pp. 146134842110081
Author(s):  
Xia Hua ◽  
Alan Thomas
Keyword(s):  
Lithium Ion Batteries ◽  
Lithium Ion Battery ◽  
Experimental Studies ◽  
Lithium Ion ◽  
Battery Pack ◽  
Dynamic Loads ◽  
Electrical Performance ◽  
Mechanical Degradation ◽  
Energy Storage Devices ◽  
Battery Cell

Lithium-ion batteries are being increasingly used as the main energy storage devices in modern mobile applications, including modern spacecrafts, satellites, and electric vehicles, in which consistent and severe vibrations exist. As the lithium-ion battery market share grows, so must our understanding of the effect of mechanical vibrations and shocks on the electrical performance and mechanical properties of such batteries. Only a few recent studies investigated the effect of vibrations on the degradation and fatigue of battery cell materials as well as the effect of vibrations on the battery pack structure. This review focused on the recent progress in determining the effect of dynamic loads and vibrations on lithium-ion batteries to advance the understanding of lithium-ion battery systems. Theoretical, computational, and experimental studies conducted in both academia and industry in the past few years are reviewed herein. Although the effect of dynamic loads and random vibrations on the mechanical behavior of battery pack structures has been investigated and the correlation between vibration and the battery cell electrical performance has been determined to support the development of more robust electrical systems, it is still necessary to clarify the mechanical degradation mechanisms that affect the electrical performance and safety of battery cells.

scholarly journals A ΔSOC-based equalization strategy applied to industry

2020 ◽  
Author(s):  
Maonan Wang ◽  
Chun Chang ◽  
Feng Ji
Keyword(s):  
Open Circuit ◽  
Battery Pack ◽  
Battery Management System ◽  
Battery Management ◽  
Battery Cell ◽  
New Strategy ◽  
The Difference ◽  
Relative Errors ◽  
The Relationship ◽  
Battery Cells

Abstract The voltage-based equalization strategy is widely used in the industry because the voltage (U) of the battery cell is very easy to obtain, but it is difficult to provide an accurate parameter for the battery management system (BMS). This study proposes a new equalization strategy, which is based on the difference between the state of charge (SOC) of any two battery cells in the battery pack, that is, a ΔSOC-based equalization strategy. The new strategy is not only as simple as the voltage-based equalization strategy, but it can also provide an accurate parameter for the BMS. Simply put, using the relationship between the open circuit voltage and the SOC of the battery pack, the proposed strategy can convert the difference between the voltage of the battery cells into ΔSOC, which renders a good performance. Additionally, the required parameters are all from the BMS, and no additional calculation is required, which makes the strategy as simple as the voltage-based balancing strategy. The four experiments show that the relative errors of ΔSOC estimated by the ΔSOC-based equalization strategy are 0.37%, 0.39%, 0.1% and 0.17%, and thereby demonstrate that the ΔSOC-based equalization strategy proposed in this study shows promise in replacing the voltage-based equalization strategy within the industry to obtain better performance.

An Active Equalizer for Serially Connected Lithium-Ion Battery Cells

2013 ◽  
Vol 732-733 ◽  
pp. 809-812 ◽  
Author(s):  
Hong Rui Liu ◽  
Chao Ying Xia
Keyword(s):  
Lithium Ion Battery ◽  
Lithium Ion ◽  
State Of Charge ◽  
Experimental Results ◽  
Battery Cell ◽  
Charging Current ◽  
In Series ◽  
Battery Cells

This paper proposes an equalizer for serially connected Lithium-ion battery cells. The battery cell with the lowest state of charge (SOC) is charged by the equalizer during the process of charging and discharging, and the balancing current is constant and controllable. Three unbalanced lithium-ion battery cells in series are selected as the experimental object by this paper. The discharging current under a certain UDDS and 20A charging current are used to complete respectively one time balancing experiment of discharging and charging to the three lithium-ion battery cells. The validity of the balancing strategy is confirmed in this paper according to the experimental results.

Thermal Management of Air-Cooling Lithium-Ion Battery Pack

2021 ◽  
Vol 38 (11) ◽  
pp. 118201
Author(s):  
Jianglong Du ◽  
Haolan Tao ◽  
Yuxin Chen ◽  
Xiaodong Yuan ◽  
Cheng Lian ◽  
...  
Keyword(s):  
Lithium Ion Battery ◽  
Thermal Management ◽  
Thermal Performance ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Battery Pack ◽  
Cooling Effect ◽  
Air Cooling ◽  
Safety Issues ◽  
Battery Packs

Lithium-ion battery packs are made by many batteries, and the difficulty in heat transfer can cause many safety issues. It is important to evaluate thermal performance of a battery pack in designing process. Here, a multiscale method combining a pseudo-two-dimensional model of individual battery and three-dimensional computational fluid dynamics is employed to describe heat generation and transfer in a battery pack. The effect of battery arrangement on the thermal performance of battery packs is investigated. We discuss the air-cooling effect of the pack with four battery arrangements which include one square arrangement, one stagger arrangement and two trapezoid arrangements. In addition, the air-cooling strategy is studied by observing temperature distribution of the battery pack. It is found that the square arrangement is the structure with the best air-cooling effect, and the cooling effect is best when the cold air inlet is at the top of the battery pack. We hope that this work can provide theoretical guidance for thermal management of lithium-ion battery packs.

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