scholarly journals Li-Ion Cell Safety Monitoring Using Mechanical Parameters: Part I. Normal Battery Operation

Author(s):  
Angel Kirchev ◽  
Nicolas guillet ◽  
David Brun-Buisson ◽  
Vincent Gau

Abstract The normal operation of a 18650 Lithium-ion cells has been monitored using rectangular rosette strain gauge and a pair of piezoelectric transducers. The sensors for mechanical measurements provide information about the cell deformation mechanism and electrodes structure during the cycling. The strain gauge signal revealed three type of mechanical processes. The predominant deformation pattern during galvanostatic discharge process is an isotropic cylindrical shrinkage relevant to the extraction of lithium ions from the graphite negative electrode. In the case of low-rate discharge in cyclic voltammetry mode, the deformation pattern changes to spherical growth when the state of charge falls below 40. In contrast, the thermal shrinkage and growth of the cell corresponds to simple decrease of the cell diameter with much smaller hysteresis effect. The ultrasound interrogation is able to detect repeatable progressive change of the acoustic waveform transferred across the cell in direction of the jellyroll diameter, which depends on the state of charge and does not undergo any significant changes at different cycling rates. The impact of the state of health under 2h – rated charge/discharge cycling at 25°C reveals slow progressive drift of the strain and acoustic signals corresponding to the growth of the cell size.

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1971
Author(s):  
Lihua Ye ◽  
Muhammad Muzamal Ashfaq ◽  
Aiping Shi ◽  
Syyed Adnan Raheel Shah ◽  
Yefan Shi

In this research, the aim relates to the material characterization of high-energy lithium-ion pouch cells. The development of appropriate model cell behavior is intended to simulate two scenarios: the first is mechanical deformation during a crash and the second is an internal short circuit in lithium-ion cells during the actual effect scenarios. The punch test has been used as a benchmark to analyze the effects of different state of charge conditions on high-energy lithium-ion battery cells. This article explores the impact of three separate factors on the outcomes of mechanical punch indentation experiments. The first parameter analyzed was the degree of prediction brought about by experiments on high-energy cells with two different states of charge (greater and lesser), with four different sizes of indentation punch, from the cell’s reaction during the indentation effects on electrolyte. Second, the results of the loading position, middle versus side, are measured at quasi-static speeds. The third parameter was the effect on an electrolyte with a different state of charge. The repeatability of the experiments on punch loading was the last test function analyzed. The test results of a greater than 10% state of charge and less than 10% state of charge were compared to further refine and validate this modeling method. The different loading scenarios analyzed in this study also showed great predictability in the load-displacement reaction and the onset short circuit. A theoretical model of the cell was modified for use in comprehensive mechanical deformation. The overall conclusion found that the loading initiating the cell’s electrical short circuit is not instantaneously instigated and it is subsequently used to process the development of a precise and practical computational model that will reduce the chances of the internal short course during the crash.


2021 ◽  
Vol 10 (4) ◽  
pp. 1759-1768
Author(s):  
Mouhssine Lagraoui ◽  
Ali Nejmi ◽  
Hassan Rayhane ◽  
Abderrahim Taouni

The main goal of a battery management system (BMS) is to estimate parameters descriptive of the battery pack operating conditions in real-time. One of the most critical aspects of BMS systems is estimating the battery's state of charge (SOC). However, in the case of a lithium-ion battery, it is not easy to provide an accurate estimate of the state of charge. In the present paper we propose a mechanism based on an extended kalman filter (EKF) to improve the state-of-charge estimation accuracy on lithium-ion cells. The paper covers the cell modeling and the system parameters identification requirements, the experimental tests, and results analysis. We first established a mathematical model representing the dynamics of a cell. We adopted a model that comprehends terms that describe the dynamic parameters like SOC, open-circuit voltage, transfer resistance, ohmic loss, diffusion capacitance, and resistance. Then, we performed the appropriate battery discharge tests to identify the parameters of the model. Finally, the EKF filter applied to the cell test data has shown high precision in SOC estimation, even in a noisy system.


Nanophotonics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1071-1079 ◽  
Author(s):  
Siyu Qian ◽  
Xinlong Chen ◽  
Shiyu Jiang ◽  
Qiwen Pan ◽  
Yachen Gao ◽  
...  

AbstractSupercapacitors with high power density, ultralong lifespan and wide range operating temperature have drawn significant attention in recent years. However, monitoring the state of charge in supercapacitors in a cost-effective and flexible way is still challenging. Techniques such as transmission electron microscopy and X-ray diffraction can analyze the characteristics of supercapacitor well. But with large size and high price, they are not suitable for daily monitoring of the supercapacitors’ operation. In this paper, a low cost and easily fabricated fiber-optic localized surface plasmon resonance (LSPR) probe is proposed to monitor the state of charge of the electrode in a supercapacitor. The Au nanoparticles were loading on the fiber core as LSPR sensing region. In order to implant the fiber in the supercapacitor, a reflective type of fiber sensor was used. The results show that this tiny fiber-optic LSPR sensor can provide online monitoring of the state of charge during the charging and discharging process in situ. The intensity shift in LSPR sensor has a good linear relationship with the state of charge calculated by standard galvanostatic charging and discharging test. In addition, this LSPR sensor is insensitive to the temperature change, presenting a great potential in practical applications.


Measurement ◽  
2009 ◽  
Vol 42 (8) ◽  
pp. 1131-1138 ◽  
Author(s):  
V. Pop ◽  
H.J. Bergveld ◽  
P.H.L. Notten ◽  
J.H.G. Op het Veld ◽  
P.P.L. Regtien

2014 ◽  
Vol 63 (4) ◽  
pp. 1614-1621 ◽  
Author(s):  
Jun Xu ◽  
Chunting Chris Mi ◽  
Binggang Cao ◽  
Junjun Deng ◽  
Zheng Chen ◽  
...  

1999 ◽  
Vol 575 ◽  
Author(s):  
E. Peter Roth ◽  
G. Nagasubramanian

ABSTRACTThermal instabilities were identified in SONY-type lithium-ion cells and correlated with interactions of cell constituents and reaction products. Three temperature regions of interaction were identified and associated with the state of charge (degree of Li intercalation) of the cell. Anodes were shown to undergo exothermic reactions as low as 100°C involving the solid electrolyte interface (SEI) layer and the LiPF6 salt in the electrolyte (EC:PC:DEC/LiPF6). These reactions could account for the thermal runaway observed in these cells beginning at 100°C. Exothermic reactions were also observed in the 200°C-300°C region between the intercalated lithium anodes, the LiPF6 salt, and the PVDF. These reactions were followed by a hightemperature reaction region, 300°C-400°C, also involving the PVDF binder and the intercalated lithium anodes. The solvent was not directly involved in these reactions but served as a moderator and transport medium. Cathode exothermic reactions with the PVDF binder were observed above 200°C and increased with the state of charge (decreasing Li content). This offers an explanation for the observed lower thermal runaway temperatures for charged cells.


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