Thermal State of Charge Estimation in Phase Change Composites for Passively Cooled Lithium-Ion Battery Packs

Stroe

Journal of Cleaner Production

et al. 2020

The power state evaluation plays a decisive influence on the safety implication of the lithium battery packs, and there is no effective online evaluation method so far due to the imbalance phenomenon among the internal connected battery cells, which cannot be abstained by the advancement of the materials and techniques. A novel power state description method is proposed in this paper by investigating the improved external parameter coupling treatment, in which the mutual relationship description is conducted by the parameter information feature decomposition together with the Bayesian sequential decision algorithm. The complicated power state evaluation model constructing problem of the coupling relationship decomposition is solved by investigating the non-convex optimization under complex working conditions for the lithium battery packs. The evidence combination is realized by introducing the information fusion strategy, according to which the multi criteria decision is realized by using the evidence theory. As can be seen from the experimental results, the voltage difference is within 10 mV in both of the first phase and the second phase, which increases rapidly in the third phase and reaches a maximum of 120mV. Meanwhile, its power state evaluation accuracy is 95.00% and has a good output voltage tracking effect in the complex working conditions. The power state evaluation problem can be solved by the proposed model constructing method, which is suitable for the complex battery cell combination structures and environment influences, realizing the reliable and hierarchical power state evaluation of the lithium battery packs. It provides a safety reference value and the energy management basis for the reliable power supply in the cleaner production of the power lithium battery packs.

Section: Ukf-ekf Composite Calculationmentioning

confidence: 99%

A novel power state evaluation method for the lithium battery packs based on the improved external measurable parameter coupling model

Stroe

Journal of Cleaner Production

et al. 2020

“…7 Moreover, it can be used in high temperature conditions with a high degree of safety. 10 The iterate calculation modeling was obtained by using the co-estimator, 11 according to which the on-line working state estimation could be also investigated. 10 The iterate calculation modeling was obtained by using the co-estimator, 11 according to which the on-line working state estimation could be also investigated.…”

Section: Introductionmentioning

confidence: 99%

“…8 The battery cell voltage can describe the working state to a certain extent 9 and the internal equilibrium state of the lithium-ion battery pack can be characterized, which can improve its safety in the industrial power supply applications. 10 The iterate calculation modeling was obtained by using the co-estimator, 11 according to which the on-line working state estimation could be also investigated. 12 Then, the on-line remaining energy status named as State of Charge (SOC) was also predicted, 13 which plays an important role in the Battery Management System (BMS).…”

Section: Introductionmentioning

confidence: 99%

An improved packing equivalent circuit modeling method with the cell‐to‐cell consistency state evaluation of the internal connected lithium‐ion batteries

Shi

Energy Science & Engineering

et al. 2019

The existing equivalent modeling methods reported in literature focuses mainly on the battery cells and do not take the packing consistency state into consideration, which exists on the internal connected cells of the lithium‐ion battery pack. An improved equivalent circuit model is constructed and reported in this manuscript for the first time, which can be used to characterize the working characteristics of the packing lithium‐ion batteries. A new equilibrium concept named as state of balance is proposed as well as the calculation process, which is realized by considering the real‐time detected internal battery cell voltages. In addition, this new equilibrium concept aims to obtain more information on the real‐time consistency characterization of the battery pack. The improved adaptive equivalent circuit model is investigated by using the improved splice modeling method, in which the statistical noise properties are corrected and the additional parallel resistance‐capacitance circuit is introduced. The parameter correction treatment is carried out by comparing the estimated and experimental detected closed circuit voltages. Furthermore, the tracking error is found to be 0.005 V and accounts for 0.119% of the nominal battery voltage. By taking the packing consistency state and temperature correction into consideration, the accurate working characteristic expression is realized in the improved equivalent circuit modeling process. Finally, the model proposed in this manuscript presents a great number of advantages compared to other methods reported so far, like has the high accuracy, and the ability to protect the security of the lithium‐ion battery pack in the power supply application.

“…33 The parameter estimation and sensitivity analysis were carried out by using the electrochemical models for the LIBs, 34 which was coupled with the thermal model and used to describe the thermal performance during the cycling charge-discharge process. 39 Therefore, the breakthrough of the ECM modeling is especially important to the energy management, which is also an effective means to avoid the safety accidents. 37 As the complex series-parallel combination is used in the LIB packs to break for the limitations of cell voltage and capacity, there are differences in cell-to-cell consistency and interaction.…”

mentioning

confidence: 99%

“…38 The phenomenon of spontaneous combustion of the LIB pack caused by the invalid safety management poses a great threat to the energy security. 39 Therefore, the breakthrough of the ECM modeling is especially important to the energy management, which is also an effective means to avoid the safety accidents. 40 Under the influence of the complex cell combination structure, the ECM is the key to improve its energy utilization efficiency and safety.…”

mentioning

confidence: 99%

A novel adaptive state of charge estimation method of full life cycling lithium‐ion batteries based on the multiple parameter optimization

Cao

Energy Science & Engineering

et al. 2019

The state of charge (SoC) estimation is the safety management basis of the packing lithium‐ion batteries (LIB), and there is no effective solution yet. An improved splice equivalent modeling method is proposed to describe its working characteristics by using the state‐space description, in which the optimization strategy of the circuit structure is studied by using the aspects of equivalent mode, analog calculation, and component distribution adjustment, revealing the mathematical expression mechanism of different structural characteristics. A novel particle adaptive unscented Kalman filtering algorithm is introduced for the iterative calculation to explore the working state characterization mechanism of the packing LIB, in which the incorporate multiple information is considered and applied. The adaptive regulation is obtained by exploring the feature extraction and optimal representation, according to which the accurate SoC estimation model is constructed. The state of balance evaluation theory is explored, and the multiparameter correction strategy is carried out along with the experimental working characteristic analysis under complex conditions, according to which the optimization method is obtained for the SoC estimation model structure. When the remaining energy varies from 10% to 100%, the tracking voltage error is <0.035 V and the SoC estimation accuracy is 98.56%. The adaptive working state estimation is realized accurately, which lays a key breakthrough foundation for the safety management of the LIB packs.