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 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.

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.

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 Effect of Current Rate and Prior Cycling on the Coulombic Efficiency of a Lithium-Ion Battery

Batteries ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 57 ◽  
Author(s):  
Seyed Madani ◽  
Erik Schaltz ◽  
Søren Knudsen Kær
Keyword(s):  
Lithium Ion Batteries ◽  
Lithium Ion Battery ◽  
Coulombic Efficiency ◽  
Lithium Ion ◽  
Degradation Behavior ◽  
Battery Cell ◽  
The Third ◽  
Capacity Loss ◽  
Battery Cells

The determination of coulombic efficiency of the lithium-ion batteries can contribute to comprehend better their degradation behavior. In this research, the coulombic efficiency and capacity loss of three lithium-ion batteries at different current rates (C) were investigated. Two new battery cells were discharged and charged at 0.4 C and 0.8 C for twenty times to monitor the variations in the aging and coulombic efficiency of the battery cell. In addition, prior cycling was applied to the third battery cell which consist of charging and discharging with 0.2 C, 0.4 C, 0.6 C, and 0.8 C current rates and each of them twenty times. The coulombic efficiency of the new battery cells was compared with the cycled one. The experiments demonstrated that approximately all the charge that was stored in the battery cell was extracted out of the battery cell, even at the bigger charging and discharging currents. The average capacity loss rates for discharge and charge during 0.8 C were approximately 0.44% and 0.45% per cycle, correspondingly.

scholarly journals Material Characterization and Analysis on the Effect of Vibration and Nail Penetration on Lithium Ion Battery

2019 ◽  
Vol 10 (4) ◽  
pp. 69
Author(s):  
Ajeet Babu K. Parasumanna ◽  
Ujjwala S. Karle ◽  
Mangesh R. Saraf
Keyword(s):  
Surface Morphology ◽  
Lithium Iron Phosphate ◽  
Electrochemical Impedance ◽  
Dynamic Stiffness ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
Internal Resistance ◽  
Chemical Degradation ◽  
Battery Pack ◽  
A Cell

Battery packaging in a vehicle depends on the cell chemistry being used and its behavior plays an important role in the safety of the entire battery pack. Chemical degradation of various parts of a cell such as the cathode or anode is a concern as it adversely affects performance and safety. A cell in its battery pack once assembled can have two different mechanical abuse condition. One is the vibration generated from the vehicle and the second is the intrusion of external elements in case of accident. In this paper, a commercially available 32,700 lithium ion cell with lithium iron phosphate (LFP) chemistry is studied for its response to both the abuse conditions at two different states of charge (SoC). The primary aim of this study is to understand their effect on the surface morphology of the cathode and the anode. The cells are also characterized to study impedance behavior before and after being abused mechanically. The cells tested for vibration were also analyzed for dynamic stiffness. A microscopy technique such as scanning electron microscopy (SEM) was used to study the surface morphology and electrochemical impedance spectroscopy (EIS) characterization was carried out to study the internal resistance of the cell. It was observed that there was a drop in internal resistance and increase in the stiffness after the cells subjected to mechanical abuse. The study also revealed different morphology at the center and at the corner of the cell subjected to nail penetration at 50% SoC.

Coupled-Physics Modeling of a Lithium-Ion Battery Cylindrical Cell Microstructure

2012 ◽  
Author(s):  
Peter N. Doval ◽  
Ilya V. Avdeev
Keyword(s):  
Cross Section ◽  
Automotive Industry ◽  
Hybrid Electric Vehicle ◽  
Emerging Market ◽  
Lithium Ion ◽  
Functional Materials ◽  
Battery Pack ◽  
Cylindrical Shape ◽  
Fe Model ◽  
Battery Cell

Safety of consumer vehicles is an extremely important consideration for the automotive industry. An emerging market in the automotive industry today is the electric and hybrid-electric vehicle market. As environmental concerns grow, such vehicles will become a necessity for manufacturers to remain within increasingly stringent emissions regulations. A recent problem with the high-voltage lithium-ion batteries used in many of these vehicles is that of thermal runaway following a severe collision. This paper represents our early attempt to look at one aspect of this extensive project — a coupled-physics model of battery cell microstructure. In this case, couple-physics refers only to thermal-structural coupling and the microstructure being studied here is the laminate-level structure. A 2-D finite element model of a lithium-ion cell was therefore developed. This 2-D model of the cell, also called a jellyroll, is a cross-section cut of one cell within a battery pack. Each battery cell is an assembly of alternating thin sheets of functional materials (anode, separator and cathode), which are rolled into a cylindrical shape. The cross-section then takes the form of a layered spiral. The typical cell is made of an aluminum cathode with coating, copper anode with coating, and a non-linear, viscoelastic polymer separator. Once the 2-D jellyroll FE model was created, some initial structural element simulations were run to validate the geometry setup and model integrity. Next, thermal-structural coupled-field simulations were run to investigate stress propagation resulting from thermal loads as well as the same loading cases performed with the structural-only model. Different loading conditions, including uniaxial stress-strain state, hydrostatic pressure test, and thermo-mechanical loading were simulated. The results from the simulations performed in the project set the groundwork of future models involving electrical properties and models of 3-D cells and the full battery pack.

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