The current work is concerned with preparing cobalt manganese ferrite (Co1-xMnxFe2O4) with different concentrations of cobalt and manganese (x= 0.2, 0.4, and 0.6) and decorating it with polyaniline (PAni) for use in supercapacitive applications. The results of the X-Ray diffraction (XRD) manifested a broad peak of PAni and a cubic structure of cobalt manganese ferrite having crystal size between 60 nm - 138 nm, which decreases with increasing concentration of Mn. The field emission scanning electron microscopy (FE-SEM) images evidenced that the PAni has nanofiber (NFs) structures, according to the method of preparation, where the hydrothermal method was used. The magnetic properties of the prepared ferrite, as well as the prepared PAni/Co1-xMnxFe2O4 composites, were studied through the vibrating sample magnetometer (VSM) analysis, where the magnetic hysteresis loops of ferrite elucidated a significant influence on the manganese content and the decorated PAni, through the decrease of both saturation magnetism (Ms) and remnant magnetism (Mr) in addition to the corrosive field (Hc). Increasing the content of manganese in the composites led to an improvement in the energy storage performance of the capacitors, which were tested in 1 M of H2SO4 by using the CV cyclic voltammetry analysis, galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). Increasing the manganese content caused an increase in the specific capacity and a significant increase in the charging and discharging time; the highest capacitance is 556 F/g.
{"title":"Electrochemical performance of Co1-xMnxFe2O4 decorated nanofiber Polyaniline (PAni) composites","authors":"Sura R. Mohammed, M. Ismail, I. Ibrahim","doi":"10.1115/1.4063303","DOIUrl":"https://doi.org/10.1115/1.4063303","url":null,"abstract":"\u0000 The current work is concerned with preparing cobalt manganese ferrite (Co1-xMnxFe2O4) with different concentrations of cobalt and manganese (x= 0.2, 0.4, and 0.6) and decorating it with polyaniline (PAni) for use in supercapacitive applications. The results of the X-Ray diffraction (XRD) manifested a broad peak of PAni and a cubic structure of cobalt manganese ferrite having crystal size between 60 nm - 138 nm, which decreases with increasing concentration of Mn. The field emission scanning electron microscopy (FE-SEM) images evidenced that the PAni has nanofiber (NFs) structures, according to the method of preparation, where the hydrothermal method was used. The magnetic properties of the prepared ferrite, as well as the prepared PAni/Co1-xMnxFe2O4 composites, were studied through the vibrating sample magnetometer (VSM) analysis, where the magnetic hysteresis loops of ferrite elucidated a significant influence on the manganese content and the decorated PAni, through the decrease of both saturation magnetism (Ms) and remnant magnetism (Mr) in addition to the corrosive field (Hc). Increasing the content of manganese in the composites led to an improvement in the energy storage performance of the capacitors, which were tested in 1 M of H2SO4 by using the CV cyclic voltammetry analysis, galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). Increasing the manganese content caused an increase in the specific capacity and a significant increase in the charging and discharging time; the highest capacitance is 556 F/g.","PeriodicalId":15579,"journal":{"name":"Journal of Electrochemical Energy Conversion and Storage","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43712305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Electrochemical actuators can convert electrical energy into mechanical energy directly and have been applied widely. With a large volume expansion in the electrochemical reaction, silicon material demonstrates enormous potential in the manufacture of the electrochemical actuators. Here, we propose a new electrochemical actuator based on Si/CNTs composite electrode. A mathematical model is developed to analyze the relationship among material parameters, structural changes, and bending deformation. The curvature changes of the cantilever beam are captured by a CCD camera during electrochemical cycling. Combining the model and bending curvatures, the modulus and swell strain are extracted and detailed analyzed. Here, the elastic modulus of the composite electrode softens and decreases from 9.59 GPa to 4.78 GPa, while the swell strain increases from 0.12% to 2.97% when arriving 6% normalized concentration of lithium. These results show that the composite material possesses excellent bending resistance and deformation ability. Also, the curvature changes under different thickness ratios are predicted successfully, the evolution of stress in the working electrode is simulated, and the loading experiment of the actuator is carried out. This work provides a new way to realize the controllability of the electrochemical actuators.
{"title":"Experimental investigation and controllability study of electrochemical actuators based on Si/CNTs composite material","authors":"Zhilin Wu, Xiaobing Yang, Kai Sheng, Dawei Li","doi":"10.1115/1.4063057","DOIUrl":"https://doi.org/10.1115/1.4063057","url":null,"abstract":"\u0000 Electrochemical actuators can convert electrical energy into mechanical energy directly and have been applied widely. With a large volume expansion in the electrochemical reaction, silicon material demonstrates enormous potential in the manufacture of the electrochemical actuators. Here, we propose a new electrochemical actuator based on Si/CNTs composite electrode. A mathematical model is developed to analyze the relationship among material parameters, structural changes, and bending deformation. The curvature changes of the cantilever beam are captured by a CCD camera during electrochemical cycling. Combining the model and bending curvatures, the modulus and swell strain are extracted and detailed analyzed. Here, the elastic modulus of the composite electrode softens and decreases from 9.59 GPa to 4.78 GPa, while the swell strain increases from 0.12% to 2.97% when arriving 6% normalized concentration of lithium. These results show that the composite material possesses excellent bending resistance and deformation ability. Also, the curvature changes under different thickness ratios are predicted successfully, the evolution of stress in the working electrode is simulated, and the loading experiment of the actuator is carried out. This work provides a new way to realize the controllability of the electrochemical actuators.","PeriodicalId":15579,"journal":{"name":"Journal of Electrochemical Energy Conversion and Storage","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48745520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Ram, Shanal Kumar, Vincent Léchappé, A. Mohammadi, Maurizio Cirrincione
The paper presents a simplified nonlinear model for an open cathode proton exchange membrane fuel cell (PEMFC) and its control by using three different strategies. The model presented uses four state variables. The mass flow of oxygen, hydrogen flow, water and temperature were taken to be the critical dynamics in the system. The unknown parameters were estimated using the experimental data of a 1.2 kW PEMFC. The simplified model showed good agreement with experimental results. Control schemes were implemented to control the stack temperature of the PEMFC. The proportional (P) and proportional-integral (PI) Control performed well but had a poorer response compared to the sliding mode control (SMC) scheme. The study of the different control schemes reveals the dangers of singularly controlling either the oxygen excess ratio or the temperature. Results show the best control is achieved when the excess ratio is control through the reference temperature. The study also compares the parasitic losses from the fans caused by the different controllers. Overall the results provide a good insight into designing a robust control system for an open cathode PEMFC for faster response and greater durability.
{"title":"Thermal and Air Management of an Open Cathode PEM Fuel Cell using Sliding Mode Control","authors":"K. Ram, Shanal Kumar, Vincent Léchappé, A. Mohammadi, Maurizio Cirrincione","doi":"10.1115/1.4063056","DOIUrl":"https://doi.org/10.1115/1.4063056","url":null,"abstract":"\u0000 The paper presents a simplified nonlinear model for an open cathode proton exchange membrane fuel cell (PEMFC) and its control by using three different strategies. The model presented uses four state variables. The mass flow of oxygen, hydrogen flow, water and temperature were taken to be the critical dynamics in the system. The unknown parameters were estimated using the experimental data of a 1.2 kW PEMFC. The simplified model showed good agreement with experimental results. Control schemes were implemented to control the stack temperature of the PEMFC. The proportional (P) and proportional-integral (PI) Control performed well but had a poorer response compared to the sliding mode control (SMC) scheme. The study of the different control schemes reveals the dangers of singularly controlling either the oxygen excess ratio or the temperature. Results show the best control is achieved when the excess ratio is control through the reference temperature. The study also compares the parasitic losses from the fans caused by the different controllers. Overall the results provide a good insight into designing a robust control system for an open cathode PEMFC for faster response and greater durability.","PeriodicalId":15579,"journal":{"name":"Journal of Electrochemical Energy Conversion and Storage","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44175269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Huazhong Ma, Sheng-Rong He, Xingyu Ma, Yaoyue Yang
Metal-metal (hydr)oxide interfaces can promote the CO2 selectivity of ethanol oxidation reaction (EOR) due to so-called metal-oxide-interaction (MOI). Here, we first show that the mixture of Ir and PbO species at the nanoscale can also form “bifunctional effect” sites, where C-C bond of ethanol can be effective cut at Ir sites to generate C1 intermediates, and nearby PbO species could provide oxygenated-species. Actually, the as-prepared Ir-PbO/C catalysts with a mean metallic nanoparticle size of 2.6±0.5 nm can greatly improve the activity, stability and C1 pathway selectivity of EOR. Specifically, it exhibits superior mass activity of 1150 mA mg−1Ir in 1 M NaOH solution containing 1 M C2H5OH. Chronoamperometry tests show that the stability of Ir-PbO/C is also significantly improved compared with Ir/C. In situ electrochemical infrared absorption spectral results confirm that the addition of oxophilic PbO species could accelerate the oxidative removal of COad intermediates, thereby greatly improving catalytic performance. This study may give new insights into designing efficient anode catalysts for the direct ethanol fuel cells (DEFCs).
由于所谓的金属-氧化物相互作用（MOI），金属-金属（hydr）-氧化物界面可以提高乙醇氧化反应（EOR）的CO2选择性。在这里，我们首先表明，在纳米尺度上，Ir和PbO物种的混合物也可以形成“双功能效应”位点，其中乙醇的C-C键可以在Ir位点被有效切割以产生C1中间体，而附近的PbO物种可以提供含氧物种。事实上，所制备的平均金属纳米颗粒尺寸为2.6±0.5nm的Ir-PbO/C催化剂可以大大提高EOR的活性、稳定性和C1途径选择性。具体而言，它在含有1M C2H5OH的1M NaOH溶液中表现出1150 mA mg−1Ir的优异质量活性。计时电流法测试表明，与Ir/C相比，Ir-PbO/C的稳定性也显著提高。原位电化学红外吸收光谱结果证实，亲氧PbO物种的加入可以加速COad中间体的氧化去除，从而大大提高催化性能。这项研究可能为设计高效的直接乙醇燃料电池阳极催化剂提供新的见解。
{"title":"Promoting Effect of PbO on Ir Nanosurface Towards Ethanol Electrocatalytic Oxidation in Alkaline Media","authors":"Huazhong Ma, Sheng-Rong He, Xingyu Ma, Yaoyue Yang","doi":"10.1115/1.4063017","DOIUrl":"https://doi.org/10.1115/1.4063017","url":null,"abstract":"\u0000 Metal-metal (hydr)oxide interfaces can promote the CO2 selectivity of ethanol oxidation reaction (EOR) due to so-called metal-oxide-interaction (MOI). Here, we first show that the mixture of Ir and PbO species at the nanoscale can also form “bifunctional effect” sites, where C-C bond of ethanol can be effective cut at Ir sites to generate C1 intermediates, and nearby PbO species could provide oxygenated-species. Actually, the as-prepared Ir-PbO/C catalysts with a mean metallic nanoparticle size of 2.6±0.5 nm can greatly improve the activity, stability and C1 pathway selectivity of EOR. Specifically, it exhibits superior mass activity of 1150 mA mg−1Ir in 1 M NaOH solution containing 1 M C2H5OH. Chronoamperometry tests show that the stability of Ir-PbO/C is also significantly improved compared with Ir/C. In situ electrochemical infrared absorption spectral results confirm that the addition of oxophilic PbO species could accelerate the oxidative removal of COad intermediates, thereby greatly improving catalytic performance. This study may give new insights into designing efficient anode catalysts for the direct ethanol fuel cells (DEFCs).","PeriodicalId":15579,"journal":{"name":"Journal of Electrochemical Energy Conversion and Storage","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47320759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We developed a three-dimensional multiphysics numerical model of a Proton Exchange Mem-brane Fuel Cell (PEMFC) with a cathode mesh structure to investigate how coolant flow rate and temperature impact its performance. After experimentally validating the model, we compared the performance of the cathode mesh structure PEMFC with that of the traditional straight flow PEMFC. The results indicate that the cathode mesh structure PEMFC has a lower pressure drop and a more index of uniform distribution (IUD), leading to enhanced performance, better temperature distribution, and improved water management of the PEMFC. The investigation of the cooling system's operating parameters revealed that the temperature of the cathode catalyst layer in the PEMFC is the highest, while the temperature of the bipolar plate is the lowest. Of the nine cases that we evaluated, Case 7, with a coolant inlet temperature and flow rate of 303.15 K and 0.07 m s−1, respectively, yielded the highest power density and the lowest average temperature. The IUD of the PEM in Case 5 was 0.608, suggesting that the temperature distribution of the PEM is more uniform when the coolant inlet temperature and flow rate are 323.15 K and 0.05 m s−1, respectively. We have demonstrated through calculations that there is a strong correlation between temperature difference and IUDs. These findings have significant implications for the optimization and application of PEMFCs.
我们开发了一个具有阴极网格结构的质子交换膜燃料电池（PEMFC）的三维多物理数值模型，以研究冷却剂流速和温度如何影响其性能。在对模型进行实验验证后，我们将阴极网状结构的PEMFC与传统的直流PEMFC的性能进行了比较。结果表明，阴极网状结构的PEMFC具有更低的压降和更多的均匀分布指数（IUD），从而提高了PEMFC的性能、更好的温度分布和改进的水管理。对冷却系统运行参数的研究表明，PEMFC中阴极催化剂层的温度最高，而双极板的温度最低。在我们评估的九种情况中，冷却液入口温度和流速分别为303.15 K和0.07 m s−1的情况7产生了最高的功率密度和最低的平均温度。案例5中PEM的IUD为0.608，表明当冷却剂入口温度和流速分别为323.15 K和0.05 m s−1时，PEM的温度分布更加均匀。我们已经通过计算证明，温差和宫内节育器之间有很强的相关性。这些发现对PEMFC的优化和应用具有重要意义。
{"title":"Effects of Cooling System Boundary Conditions on the Performance of Proton Exchange Membrane Fuel Cell: A Comprehensive Analysis","authors":"Yaochen Wang, H. Ren, Cong Li","doi":"10.1115/1.4063016","DOIUrl":"https://doi.org/10.1115/1.4063016","url":null,"abstract":"\u0000 We developed a three-dimensional multiphysics numerical model of a Proton Exchange Mem-brane Fuel Cell (PEMFC) with a cathode mesh structure to investigate how coolant flow rate and temperature impact its performance. After experimentally validating the model, we compared the performance of the cathode mesh structure PEMFC with that of the traditional straight flow PEMFC. The results indicate that the cathode mesh structure PEMFC has a lower pressure drop and a more index of uniform distribution (IUD), leading to enhanced performance, better temperature distribution, and improved water management of the PEMFC. The investigation of the cooling system's operating parameters revealed that the temperature of the cathode catalyst layer in the PEMFC is the highest, while the temperature of the bipolar plate is the lowest. Of the nine cases that we evaluated, Case 7, with a coolant inlet temperature and flow rate of 303.15 K and 0.07 m s−1, respectively, yielded the highest power density and the lowest average temperature. The IUD of the PEM in Case 5 was 0.608, suggesting that the temperature distribution of the PEM is more uniform when the coolant inlet temperature and flow rate are 323.15 K and 0.05 m s−1, respectively. We have demonstrated through calculations that there is a strong correlation between temperature difference and IUDs. These findings have significant implications for the optimization and application of PEMFCs.","PeriodicalId":15579,"journal":{"name":"Journal of Electrochemical Energy Conversion and Storage","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47602791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fast charging has become the norm for various electronic products. The research on the state of health (SOH) prediction of fast-charging lithium-ion battery deserves more attention. In this paper, a model-data fusion SOH prediction method which can reflect the degradation mechanism of fast-charging battery is proposed. Firstly, based on the Arrhenius model, the logarithmic-power function (LP) model and logarithmic-linear (LL) model related to the fast-charging rate are established. Secondly, combined with Gaussian process regression (GPR) prediction, particle filter is used to update the parameters of models in real time. Compared with the single GPR, the average root mean square error of LP and LL are reduced by 71.56% and 69.11%, respectively. Finally, the sensitivity and superiority of the two models are analyzed by using Sobol method, Akaike and Bayesian Information Criterion. The results show that the two models are more suitable for fast-charging lithium batteries than the traditional Arrhenius model, and LP model is better than LL model.
{"title":"A approach for fast-charging lithium-ion batteries state of health prediction based on model-data fusion","authors":"Hailin Feng, Yatian Liu","doi":"10.1115/1.4062990","DOIUrl":"https://doi.org/10.1115/1.4062990","url":null,"abstract":"\u0000 Fast charging has become the norm for various electronic products. The research on the state of health (SOH) prediction of fast-charging lithium-ion battery deserves more attention. In this paper, a model-data fusion SOH prediction method which can reflect the degradation mechanism of fast-charging battery is proposed. Firstly, based on the Arrhenius model, the logarithmic-power function (LP) model and logarithmic-linear (LL) model related to the fast-charging rate are established. Secondly, combined with Gaussian process regression (GPR) prediction, particle filter is used to update the parameters of models in real time. Compared with the single GPR, the average root mean square error of LP and LL are reduced by 71.56% and 69.11%, respectively. Finally, the sensitivity and superiority of the two models are analyzed by using Sobol method, Akaike and Bayesian Information Criterion. The results show that the two models are more suitable for fast-charging lithium batteries than the traditional Arrhenius model, and LP model is better than LL model.","PeriodicalId":15579,"journal":{"name":"Journal of Electrochemical Energy Conversion and Storage","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45947563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This review article addresses microbial fuel cells (MFCs) as a renewable energy source. MFCs are bioelectrochemical systems that use exoelectrogenic bacterial communities under anaerobic conditions to convert chemical energy into electrical energy. These systems are attracting attention due to their potential to reduce overall energy consumption, produce zero carbon emissions, and exhibit high energy density. The rapid development of renewable energy sources has increased the potential for bioenergy, particularly MFCs, to become one of the most important energy sources of the future. In addition to energy production, MFCs show potential for bioremediation and efficient removal of various pollutants. While MFC technology currently has limited application at the laboratory level, it is expected to increase in commercial use in the near future and offers great potential in the areas of renewable energy and environmental sustainability. This review article focuses on the historical and ecological development of the components used in MFCs, examining in detail their evolution and use in MFCs for renewable energy production.
{"title":"Components used in microbial fuel cells (MFCs) for renewable energy generation: A review of their historical and ecological development","authors":"Necla Altin, R. G. Akay","doi":"10.1115/1.4062991","DOIUrl":"https://doi.org/10.1115/1.4062991","url":null,"abstract":"\u0000 This review article addresses microbial fuel cells (MFCs) as a renewable energy source. MFCs are bioelectrochemical systems that use exoelectrogenic bacterial communities under anaerobic conditions to convert chemical energy into electrical energy. These systems are attracting attention due to their potential to reduce overall energy consumption, produce zero carbon emissions, and exhibit high energy density. The rapid development of renewable energy sources has increased the potential for bioenergy, particularly MFCs, to become one of the most important energy sources of the future. In addition to energy production, MFCs show potential for bioremediation and efficient removal of various pollutants. While MFC technology currently has limited application at the laboratory level, it is expected to increase in commercial use in the near future and offers great potential in the areas of renewable energy and environmental sustainability. This review article focuses on the historical and ecological development of the components used in MFCs, examining in detail their evolution and use in MFCs for renewable energy production.","PeriodicalId":15579,"journal":{"name":"Journal of Electrochemical Energy Conversion and Storage","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44445240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To solve the problem of inconsistency in the use of series-connected lithium-ion battery packs, this paper proposed a topological structure of dual-layer equalization based on a flying capacitor circuit and Cuk circuit, as well as a control strategy seeking the shortest equalization path. In this structure, batteries are divided into two forms: intra-group and inter-group; the intra-group equalization is the lower-level equalization while the flying capacitor circuit is used as an equalization circuit to achieve equalization between individual battery cells; the inter-group equalization is the upper-level equalization while Cuk circuit is used as equalization circuit to achieve equalization between battery packs; each battery pack shares a battery cell, thus to obtain more options on equalization path. The proposed strategy, with State of Charge as the balancing variable, represents topological structure of the circuit in form of graph by adopting graph theory control, seeks the optimal equalization path via ant colony optimization algorithm with global search, thus to improve the equalization speed and efficiency. At last, the structure and the strategy proposed in this paper were simulated in MATLAB/Simulink to compare with the maximum value equalization method in the condition of static, charging, and discharging. The result of the simulation experiments shows that the equalization method based on graph theory control reduces the equalization duration by approximately 17%, and improves the equalization efficiency by approximately 2%, which verifies the superiority and effectiveness of the structure and strategy proposed in this paper.
{"title":"Research on Two-level Equalization Strategy of Lithium-ion Battery Based on Graph Theory","authors":"Tiezhou Wu, Houjia Li, Hongguang Li, Rui Zhao","doi":"10.1115/1.4062989","DOIUrl":"https://doi.org/10.1115/1.4062989","url":null,"abstract":"\u0000 To solve the problem of inconsistency in the use of series-connected lithium-ion battery packs, this paper proposed a topological structure of dual-layer equalization based on a flying capacitor circuit and Cuk circuit, as well as a control strategy seeking the shortest equalization path. In this structure, batteries are divided into two forms: intra-group and inter-group; the intra-group equalization is the lower-level equalization while the flying capacitor circuit is used as an equalization circuit to achieve equalization between individual battery cells; the inter-group equalization is the upper-level equalization while Cuk circuit is used as equalization circuit to achieve equalization between battery packs; each battery pack shares a battery cell, thus to obtain more options on equalization path. The proposed strategy, with State of Charge as the balancing variable, represents topological structure of the circuit in form of graph by adopting graph theory control, seeks the optimal equalization path via ant colony optimization algorithm with global search, thus to improve the equalization speed and efficiency. At last, the structure and the strategy proposed in this paper were simulated in MATLAB/Simulink to compare with the maximum value equalization method in the condition of static, charging, and discharging. The result of the simulation experiments shows that the equalization method based on graph theory control reduces the equalization duration by approximately 17%, and improves the equalization efficiency by approximately 2%, which verifies the superiority and effectiveness of the structure and strategy proposed in this paper.","PeriodicalId":15579,"journal":{"name":"Journal of Electrochemical Energy Conversion and Storage","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48922414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anshul Nagar, A. Garg, Surinder Singh, L. Gao, Jonghoon Kim, Kexiang Wei
Understanding Solid Electrolyte Interphase (SEI) is essential for diagnosis of Lithium-ion batteries because many aspects of battery performance such as safety and efficiency depends on this characteristics.. LiF, Li2O, and Li2CO3 are important inorganic components of SEI. This electrode-electrolyte surface forms during the battery's first charging/ discharging cycle, preventing electrons' movement through the electrolyte and stabilizing the Lithium-ion battery. However, the concern is inorganic SEI components cause rate limitation of Lithium-ion diffusivity through the SEI layer. Lithium-ion diffusivity through the SEI layer depends on many factors such as temperature, the width of the SEI layer, and the concentration/density of the layer. Lithium-ion diffusivity dependence on temperature, at working temperatures of lithium-ion batteries was observed at temperatures from 250 K to 400 K and diffusion coefficient data at higher temperatures also been observed. Lithium-ion diffusivity at varying concentration/density was also observed in this paper using the Reactive force field (ReaxFF) molecular dynamic simulation. To improve the Lithium-ion diffusivity, vacancy defects were created in the inorganic components of SEI layer LiF, Li2O, and Li2CO3 and observed the diffusion coefficient using the ReaxFF molecular dynamic simulations. Another approach to improve the Lithium-ion diffusivity, is doping alkali metal ions such Na, Ca, K and Mg in the inorganic components of SEI layers of LiF, Li2O, and Li2CO3 is simulated using the Universal Force Field (UFF), and diffusion coefficient was observed.
了解固体电解质界面(SEI)对于锂离子电池的诊断至关重要，因为电池性能的许多方面，如安全性和效率取决于该特性。LiF、Li2O和Li2CO3是SEI的重要无机组分。这种电极-电解质表面在电池的第一次充电/放电循环中形成，防止电子通过电解质运动，稳定锂离子电池。然而，令人担忧的是，无机SEI成分会导致锂离子通过SEI层的扩散速率限制。锂离子通过SEI层的扩散率取决于许多因素，如温度、SEI层的宽度和层的浓度/密度。研究了锂离子电池在250 ~ 400 K工作温度下的扩散系数随温度的变化规律，以及在更高温度下的扩散系数数据。本文还利用反应力场(ReaxFF)分子动力学模拟，观察了不同浓度/密度下锂离子的扩散率。为了提高锂离子的扩散系数，在SEI层的无机组分LiF、Li2O和Li2CO3中制造了空位缺陷，并利用ReaxFF分子动力学模拟观察了扩散系数。另一种提高锂离子扩散系数的方法是在LiF、Li2O和Li2CO3的SEI层的无机组分中掺杂Na、Ca、K和Mg等碱金属离子，并利用通用力场(Universal Force Field, UFF)进行模拟，观察扩散系数。
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With the retirement of a large number of lithium-ion batteries from electric vehicles(EVs), their reuse has received increasing attention. However, a retired battery pack is not suitable for direct reuse due to the poor consistency of in-pack batteries. This paper proposes a method of retired lithium-ion battery screening based on support vector machine(SVM) with a multi-class kernel function. First, 10 new NCR18650B batteries were used to carry out the aging experiments for collecting the main parameters, such as capacity, voltage and direct current resistance(DCR). Second, a SVM based on a multi-class kernel function was proposed to screen retired batteries. To improve the screening efficiency, a capacity/voltage second-order conductance curve was adopted to extract their capacity features quickly, and four new feature points were selected as the input of the SVM to classify retired batteries. Finally, the retired batteries are accurately divided into four classes by the trained model, and the classification accuracy can reach 97%. Compared with the traditional method, the feature extraction time can be reduced by four-fifths, and the screening efficiency is greatly improved.
{"title":"A screening method for retired lithium-ion batteries based on support vector machine with a multi-class kernel function","authors":"Qiang Hao, Liu Yuanlin, Zhang Wangjie","doi":"10.1115/1.4062988","DOIUrl":"https://doi.org/10.1115/1.4062988","url":null,"abstract":"\u0000 With the retirement of a large number of lithium-ion batteries from electric vehicles(EVs), their reuse has received increasing attention. However, a retired battery pack is not suitable for direct reuse due to the poor consistency of in-pack batteries. This paper proposes a method of retired lithium-ion battery screening based on support vector machine(SVM) with a multi-class kernel function. First, 10 new NCR18650B batteries were used to carry out the aging experiments for collecting the main parameters, such as capacity, voltage and direct current resistance(DCR). Second, a SVM based on a multi-class kernel function was proposed to screen retired batteries. To improve the screening efficiency, a capacity/voltage second-order conductance curve was adopted to extract their capacity features quickly, and four new feature points were selected as the input of the SVM to classify retired batteries. Finally, the retired batteries are accurately divided into four classes by the trained model, and the classification accuracy can reach 97%. Compared with the traditional method, the feature extraction time can be reduced by four-fifths, and the screening efficiency is greatly improved.","PeriodicalId":15579,"journal":{"name":"Journal of Electrochemical Energy Conversion and Storage","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42606877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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