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Evaluation of External Short-Circuit Safety of NCM/C Li-Ion Power Battery under Different State of Health

CATARC-Chunjing Lin, Fang Wang, Bin Fan
Harbin Institute of Technology-Peixia Yang
  • Technical Paper
  • 2020-01-0454
To be published on 2020-04-14 by SAE International in United States
With the increasing frequency of fire incidents of electric vehicles, the safety of power batteries has attracted more and more attention. At present, the research on the safety of power batteries is mainly focused on fresh batteries. As the state of health of batteries deepens, how the safety of the battery evolves is not clear enough so far. This paper analyzes the external short-circuit safety of a NCM/C rectangular battery under different state of charges. The results show that when the cycle number is less than 800, the maximum temperature of the battery during short-circuit is below 130 °C. The main failure mode of the battery is bulging in volume or opening of the explosion-proof valve and there is no obvious regularity between the failure mode with the cycle life. However, when the cycle number reaches 1000, the battery goes into thermal runaway during the safety test. In specific, the explosion-proof valve opens, and a large amount of smoke is sprayed, and the surface temperature of the battery reaches 350 °C with obvious burn marks.…
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Thermal Uniformity of Pouch-Type Lithium Ion Batteries with NCM Cathode Materials under Different Operating Conditions

CATARC-Chunjing Lin, Yifan Liu, Jinjie Zhang, Liqiong Han, Bin Fan, Yunjun Luo, Fang Wang
Published 2019-04-02 by SAE International in United States
With the advantages of flexible size and high energy density etc., pouch-type lithium ion battery cells with large capacity have been found more and more applications in electric vehicles. For these large-scale battery cells, thermal uniformity is vital for their safety and cycle life. To be specific, temperature gradients are expected to cause different degradation rates of active materials in different areas, which is possible to cause early failure or even fire and explosion of the battery cell. Thus, it is necessary to illustrate the batterie’s thermal uniformity in detail under different operating conditions. This work investigated the thermal uniformity of two 36 Ah pouch-type NCM/C battery cells with different sizes using both the thermal imaging method and thermoelectric effect method with K-type thermocouples. Experimental results show that there is an obvious temperature gradient on the surface of the pouch-type battery cell. The temperature of the positive electrode is significantly higher than other regions, which denotes that cooling the electrodes could a possible and effective solution for battery thermal management system. The current rare and…
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An Adaptive Neuro-Fuzzy Inference System (ANFIS) Based Model for the Temperature Prediction of Lithium-Ion Power Batteries

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

China Automotive Technology and Research Center Co., Ltd. (CATARC)-Bin Fan, Chunjing Lin, Fang Wang, Shiqiang Liu, Lei Liu
Tongji University-Sichuan Xu
  • Journal Article
  • 07-12-01-0001
Published 2018-08-14 by SAE International in United States
Li-ion batteries have been widely applied in the areas of personal electronic devices, stationary energy storage system and electric vehicles due to their high energy/power density, low self-discharge rate and long cycle life etc. For the better designs of both the battery cells and their thermal management systems, various numerical approaches have been proposed to investigate the thermal performance of power batteries. Without the requirement of detailed physical and thermal parameters of batteries, this article proposed a data-driven model using the adaptive neuro-fuzzy inference system (ANFIS) to predict the battery temperature with the inputs of ambient temperature, current and state of charge. Thermal response of a Li-ion battery module was experimentally evaluated under various conditions (i.e. ambient temperature of 0, 5, 10, 15 and 20 °C, and current rate of C/2, 1C and 2C) to acquire the necessary data sets for model development and validation. A Sugeno-type ANFIS model was tuned using the obtained data. The numbers of input membership functions (MFs) representing the three input parameters of this model are 1, 2, 3, respectively.…
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Experimental Study on the Internal Resistance and Heat Generation Characteristics of Lithium Ion Power Battery with NCM/C Material System

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Beijing Institute of Technology-Jing Wang, Chuncheng Liu, Yuefeng Su, Shi Chen, Feng Wu
China Automotive Technology and Research Center Co., Ltd.-Shiqiang Liu, Chunjing Lin, Fang Wang
  • Journal Article
  • 07-11-02-0012
Published 2018-04-18 by SAE International in United States
Heat generation characteristics of lithium ion batteries are vital for both the optimization of the battery cells and thermal management system design of battery packs. Compared with other factors, internal resistance has great influence on the thermal behavior of Li-ion batteries. Focus on a 3 Ah pouch type battery cell with the NCM/C material system, this article quantitatively evaluates the battery heat generation behavior using an Extended Volume-Accelerating Rate Calorimeter in combination with a battery cycler. Also, internal resistances of the battery cell are measured using both the hybrid pulse power characteristic (HPPC) and electro-chemical impedance spectroscopy (EIS) methods. Experimental results show that the overall internal resistance obtained by the EIS method is close to the ohmic resistance measured by the HPPC method. Heat generation power of the battery cell is small during discharge processes lower than 0.5 C-rate. The curve of heat generation power vs. time shows a U-shaped characteristic that displays some symmetry when the current rate is high. Compared with the EIS method, internal resistances measured by the HPPC method have a…
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A Modified Chirp Sequence Design for Monopulse Automotive Radar

Automotive Sensors Group-Libo Huang
China Automotive Engrg Rsch Inst Co Ltd-Tao Chen
Published 2017-09-23 by SAE International in United States
In the last years, in order to fit the requirements of automotive radar application under the multi-target conditions, several proposals about Continuous Waveform (CW)have been developed. The transmit signal with Multiple Frequency Shift Keying (MFSK) technology was developed to analyze the target information in range domain and Doppler frequency domain simultaneously, but the MFSK waveform has lower estimation accuracy in phase measuring. A higher accuracy signal type is the chirp sequence waveform of monopulse radar, which is based on two-dimension independent frequency measuring. It can also get the range and velocity information, but might lead to ambiguities in Doppler domain. To avoid the Doppler ambiguity, a method is proposed in this paper, which uses the modified chirp sequence waveform. The carrier frequencies of the modified chirp sequence are different, which causes the Doppler frequency offset. Doppler ambiguities have no influence on the Doppler frequency offset and the speed of targets can be derived from carrier frequency offset and Doppler frequency offset. Thus, the modified chirp sequence avoids the ambiguities in velocity and guarantees the measurement…
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Study of Engine Knock in HCCI Combustion using Large Eddy Simulation and Complex Chemical Kinetics

Tsinghua Univ.-Zhi Wang, Fang Wang, Shi-Jin Shuai
Published 2014-10-13 by SAE International in United States
This paper studied the knock combustion process in gasoline HCCI engines. The complex chemical kinetics was implemented into the three-dimensional CFD code with LES (Large eddy simulation) to study the origin of the knock phenomena in HCCI combustion process. The model was validated using the experimental data from the cylinder pressure measurement. 3D-CFD with LES method gives detailed turbulence, species, temperature and pressure distribution during the gasoline HCCI combustion process. The simulation results indicate that HCCI engine knock originates from the random multipoint auto-ignition in the combustion chamber due to the slight inhomogeneity. It is induced by the significantly different heat release rate of high temperature oxidation (HTO) and low temperature oxidation (LTO) and their interactions. Pressure wave occurrence can be explained by the fact of significant pressure gradients in HCCI combustion field, which caused by multipoint auto-ignition in constant-volume heat release. For instance, slightly higher temperature spots were formed before ignition due to wall heat transfer and turbulence conversion. The exceedingly exothermic HTO with rapid heat release (in microseconds) at these local zones leads…
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