This bimonthly review paper highlights 100 recent published papers on lithium batteries. We searched the Web of Science and found 3750 papers online from Oct. 1，2017 to Nov. 30，2017. 100 of them were selected to be highlighted. Layered oxide and high voltage spinel cathode materials are still under extensive investigations for the structure evolution and modifications. Large efforts were devoted to Si and Si based anode material for the effects of size and composition and electrochemical mechanism. The cycling properties of metallic lithium electrode are improved by using different kinds of  surface cover layer. The studies of solid state electrolytes are focus on the method of preparation and the transport mechanism. Additives to liquid electrolyte can help to improve the cell’s cycling performance to high voltages. There are a few papers related to Li/S battery, Li-air battery for improving their cycling performance.Theoretical works are related to the structure of bulk and interface of materials and the transportation properties. And more papers related to cell analyses, theoretical simulations, and modeling.

This nine months review paper highlights 100 recent published papers on supercapacitors. We searched the Web of Science and found more than 1400 papers online from July 1, 2017 to December 15, 2017. 100 of them were selected to be highlighted. The researches of Electrical Double-Layer Capacitor (EDLC) are mainly focused on new carbon material designed preparation, such as porous carbon materials, graphene, carbon nanotubes, and their effect on supercapacitor performance. The published papers of pseudocapacitor include four aspects, such as metal oxide composites, conductive polymer composite, heteroatom doping carbon materials and new type of pseudocapactive materials. Hybrid supercapacitor includes aqueous hybrid supercapacitor and organic hybrid supercapacitor.

Calcium chloride hexahydrate, possessing many advantages including suitable operating temperature (29℃), high enthalpy of phase change (around 191 J/g), low price and easy obtaining of raw material, security and non-toxic property, is a promising medium-low temperature phase change material in Physical energy storage. However, it suffers from sugpercooling, phase separation and leakage, which limit its applications. Generally, Nucleating agent and thickening agent can be used to solve the problems of supercooling and phase separation. Microcapsulation and porous adsorption may help to overcome the leakage problem. Although some progresses have been achieved, further explorings of modifying properties still need to be done. In this paper, the mechanisms and recent work on those problems are summarized .In addition, some predictions are presented, including using high thermal conductivity nanoparticles and porous materials to inhibit the supercooling, utilizing high thermal conductivity thickening agents or controlling the process of crystallization to prevent the phase separation, finding high thermal conductivity and high strength package materials to prevent leakage, improving the technology of making porous adsorption composites to prepare surface-clean materials and achieving multiple functions with single addictive.

 Molten salt-based nanofluids is a heat transfer fluid formed by adding nano-particles on the basis of molten salt, which can remarkably enhance the specific heat capacity and thermal conductivity of molten salt, reduce the viscosity of molten salt, and increase the heat storage density and reduce the heat storage cost is of great significance, it has become the focus of attention at home and abroad to study new medium-temperature heat transfer media. In order to further study the molten salt nanofluids to provide direction. In this paper, the latest research progress of molten salt-based nanofluids in recent years is summarized, including the preparation method, thermophysical properties and convective heat transfer of molten salt-based nanofluids. And put forward the technical problems that need to be solved in the future of molten salt-based nanofluids.

 The effects of separators consisting of cathode-side functional layers separately composed of acetylene black, Ketjen black, Super P, vapor-grown carbon fiber, graphene, carbon nano-tube and XE-2, on high sulfur-loading（5.4 mg/cm2）lithium sulfur batteries have been investigated. The separators coated by XE-2, Super P, graphene, ketjen black, vapor-grown carbon fiber can improve the electrolyte adsorbility and electrical conductivity of cathode side. Besides, the separators coated by Super P and graphene can obstruct and adsorb lithium polysulfide. The battery with separator coated by graphene delivers a specific capacity as high as 1007 mA·h/g, much higher than that of untreated separator (340 mA·h/g). After 100 cycles, the battery with separator coated by graphene can still maintain a specific discharge capacity of 539 mA·h/g, still higher than that of untreated separator (399 mA·h/g).

 A series of novel ion exchange membranes (IEM), based on sulfonated poly (ether ether ketone) (SPEEK) with different weight ratios of sulfonated graphene oxide (SGO) loadings, were employed and investigated in vanadium redox flow battery (VRB). SPEEK was obtained by sulfonation of poly (ether ether ketone) (PEEK) in concentrated H2SO4, SGO is fabricated by grafting sulfonic groups to GO via a facile method. SPEEK/SGO membranes were prepared by solution casting method. GO and SGO were characterized by Fourier transform infrared spectroscopy (FT-IR) and the physicochemical properties of all membranes were measured by water uptake (WU), ion exchange capacity (IEC), proton conductivity, vanadium ion permeability, mechanical properties, oxidation stability and single cell performance. The result of FT-IR indicated that –SO3H groups were successfully grafted to GO, SEM images revealed the good dispersion of SGO in the SPEEK matrix. And other results showed that added SGO increased the WU and proton conductivity of composite membranes, the proton selectivity of S/SGO-1 membrane (14.14×104 S·min·cm3) was 66.5% higher than that of SPEEK (8.49×104 S·min·cm3). In single cell test, VRB with S/SGO-1 showed coulombic efficiency (CE) of 95.5%, VE of 92.0% and EE of 87.8% with good cycle stability, and the self-discharge time of VRB with S/SGO-1 membrane (78 h) is longer than that of Nafion115 (30 h). All experimental results indicate that incorporation of SGO can reduce the vanadium permeability and maintain high VE of SPEEK at the same time. S/SGO IEMs, especially S/SGO-1 shows promising prospects for VRB.

The relationship between open circuit voltage and cumulative discharge capacity of lead-acid battery is the basis of lead-acid battery model, which has significant effect for the study of electrochemical reaction and mass transfer process in the battery. The data of voltage and accumulated discharge capacity during 30 times discharge processes were measured by constant current discharge method. A method to obtain open circuit voltage based on fitting and extrapolating with experimental data is proposed, which is more reasonable than the traditional one. A piecewise linear relation model for open circuit voltage and cumulative discharge capacity is derived which is based on the assumption that the rate of electrochemical reaction is in direct proportion to the square of the electrolyte concentration. Then the segmented nodes of the model are optimized by genetic algorithm before parameters are related, the results are in good agreement with the experimental data. It provides theoretical support for the study of reaction mechanism in lead-acid battery.

Distributed storage system is becoming more and more widely used in power users side. The Distributed storage system has a variety of application scenarios and it is a potentially good resource for power grids. However, it has the following problems the capacity of small quantity, uneven distribution, high cost of stand-alone access, system operation and management difficulties. These problems have brought serious challenges and technical problems to the planning and operation of power grid. This paper introduces the typical application mode and access mode of distributed energy storage on user side. The application mode and scheme of distributed energy storage under different application scenarios are described in this paper. We give the distributed energy storage effect in typical application scenarios. The analysis of the technology form and carrier of distributed energy storage will provide theoretical guidance for further research on distributed energy storage coordination control technology.

Battery energy storage is the building blocks of the Energy Internet. To improve the economy and battery life of the demand-side battery energy storage system (BESS), an optimal sizing and control method for the BESS is proposed based on an optimal scheduling approach. First, a cost-benefit analysis model is developed for evaluating the economy of demand-side energy storage. Accounting for the characteristics of battery capacity degradation under different depth of discharge (DOD) as well as the uncertainties of load and renewable generation, the optimal power and energy capacities of the BESS are determined by a stochastic scheduling method. For energy management, model predictive control is applied to adapt to the changes of the system conditions, and the profit generated by the BESS as well as the battery cycle life are optimized jointly. The proposed method considers the system operations in the planning model in order to give a more accurate evaluation of the revenues generated by the BESS. Case studies compare the economy of several types of battery energy storage including second-use batteries, and demonstrate the effectiveness of the proposed joint planning and operating method in optimizing the economic benefits of demand-side energy storage. Numerical results indicate that the economic benefits of new lead carbon batteries and second-use LiFePO4 batteries outperform new LiFePO4 batteries in terms of payback periods and annual profits.

At present, literature research on the energy storage system which is applied to control the fluctuation of new energy power generation and the control strategy of peak load shifting and valley filling has been done. Nevertheless, the feasibility of the application of the energy storage system under the mechanism of wind power prediction accuracy and the impact of wind farm benefits has not been studied. This paper proposes a control strategy of the system output to reduce wind farm short-term power prediction error for the target storage, which treats the real-time output data of wind farm (second level) as the data source and adopts the linear extrapolation method to predict the output of the wind farm at the next moment by moving average optimization. By comparing the short-term power forecast value and the real-time forecast value of wind farm and calculating the expected output of the energy storage system, simulation verification is carried out eventually after the output capacity of the energy storage system is restrained according to the output capacity of the SOC interval in the different energy storage system. The results show that the proposed control strategy of energy storage power system, can help the wind farm to meet the requirement of the short-trem power prediction accuracy assessment through the allocation of energy storage system, and has the guiding significance of lean-oriented operation and management of wind farm.

A supercapacitor will generate a lot of heat quickly in the large current charge and discharge process, which may cause security incidents. This article use thermal analysis with finite element method, firstly assumes and simplifies the structure through the analysis of a supercapacitor structure composition and analyze the unsteady heat conduction differential equation to establish the three-dimensional finite element thermal analysis model. To charge and discharge the supercapacitor with 20 A at 25 ℃[and get the temperature distribution inside the super capacitor, the temperature of the core region is the highest and the temperature is higher at the negative column area than that at the positive column area. To select the positive column, the cathode column and supercapacitor’s internal core region as the observation point, we change the current and observed temperature change over time. With increase of the charging current, the time required of internal core heat up every 100 ℃ is gradually reduced when the current is certain. As the charging current increases, the inner core of the super capacitor heat up faster. When the super capacitor use instantaneous large current to work, the internal core can reach several hundred degree centigrade in a short time, so cooling measures should be taken to avoid safety accident.

The constant current charge/discharge mode, constant voltage charge mode and constant current cycling and floating mixed mode were applied to the ageing of commercial supercapacitors at both the nominal voltage of 2.7 V and overvoltage 3.0 V, respectively, followed by the comparison of the performance of the supercapacitors, including capacitance, impedance, etc. The results show that: ① The devices aged at constant voltage mode have the highest net discharge capacity higher than the nominal capacity of 10 F and have the highest net discharge energy more than 25 m·Wh. The devices aged at constant voltage have the biggest power capacitance and energy storage capacity; ② The devices under constant current mode show the lowest capacitance of less than 10 F, but the variation of resistance and capacity are the smallest, which reveals that the devices have a longer spanlife though the devices show the worst performance. ③ The equivalent resistance of the devices under the constant current cycling and floating mixed mode is up to 37.6 mΩ (the maximum of initial value is 30 mΩ), which is higher than the devices operated at the other two modes. The results indicate that the constant current cycling and floating mixed mode seriously damaged the devices, and show the greatest effect of various voltage on the resistance of the devices. This study provides a guideline that the choice of an appropriate operating mode will significantly decrease the cost of energy storage.

 The experimental research based on anode periodic exhaust and ampere-hour integral exhaust was made on laboratory-made air-cooled proton exchange membrane fuel cell (PEMFC). The effect of different target ampere-hour integral values on output stability was studied under high load, and the optimal target ampere-hour integral value was determined as 100As. The output performance and hydrogen consumption of two exhaust methods were investigated in the condition of varying load. Compared with periodic exhaust, ampere-hour integral exhaust saved almost 30% of hydrogen, for pretty much the same performance. As the high produce cost of hydrogen, the application of ampere-hour integral exhaust can also significantly reduce the engineering cost of PEMFC.

A single cell voltage monitor system was designed and fabricated for PEM fuel cell application in this paper. This system consists of a hardware module using data collection chip, and the LabVIEW functioning as software module. It features the high-accuracy, strong anti-interference performance and real-time data display and data collection. It can be used to guarantee the stable operation of PEM fuel cell. This system was successfully applied in the performance study on a PEM fuel cell stack, and good experimental results were obtained.

To investigate the influence of heat dissipation factors on the comprehensive cooling capability for the rectangle power lithium battery, a three-dimensional transient thermal mathematical model was established under different operating conditions during charging process, making use of which the battery temperature field distribution was simulated at different charging current, ambient temperature, convective heat transfer coefficient and thermal emissivity based on the finite element method. In the meantime, the simulation results were verified experimentally, according to the results obtained by verified finite element thermal model, using the virtual orthogonal experiment method, the importance degree of influence factors was calculated and analyzed. The optimum combination of influence factors was attained, and the temperature field distribution of the original scheme(practical influence factors) and the optimized scheme(the optimum influence factors) was simulated using finite element thermal model. The results show that the thermal model of finite element is credible, and the most significant factor on the battery comprehensive cooling capacity is the charging current, whose important degree is 0.53, while the important degree of the ambient temperature is 0.21, the important degree of the convective heat transfer coefficient is 0.15, and the important degree of the thermal emissivity is 0.05, playing the least important part in the battery heat dissipation. In conclusion, the battery comprehensive cooling performance after optimization is better than that before optimization, and the virtual orthogonal experiment method has certain value of practical application in battery cooling scheme design and optimization.

In order to aid optimizing operate condition and designing control strategy, a dynamic model for the electrochemical reaction, pump loss and temperature change of the vanadium battery(VRB) was established. The model consisted of three sub-models: electrochemical model, hydraulic model and thermal model. The electrochemical model takes into account the concentration, activation, ohmic and ionic polarization losses and the vanadium ion crossover. The hydraulic model describes the hydraulic circuit of the electrolyte and determines the pumps loss. The reversible entropic heat and pumps loss are included in the thermal model. The simulation results show that the mean absolute percentage error between the simulation value and the experimental value of the stack voltage varied with the state of charge (SOCs) is 6.84%, so the accuracy of the model is verified. The model is applied to study the effects of current, electrolyte flow rate and temperature on the charge and discharge characteristics.

Through the comparison of different storage period, the thermodynamic characteristics of Zn-Ag battery AgO capacity characteristics, the effectiveness of the thermodynamic method study of AgO thermal stability and the feasibility of the battery to meet or expand the storage period are evaluated. Based on the he reaction depth at the peak and moderate peak temperature of DSC curve under different constant temperature heating conditions. A method for determining the kinetic factors E and A of AgO decomposition reaction was proposed. With the mathematical model, the decay rates of Zn-Ag battery with different storages period and under different temperatures were compared, and the method of accelerated life test for ffor Zn-Ag battery is got.

Based on the history and current habit, this paper explains and summarizes the terminology of lithium batteries. Most of words appeared in research and development are included. This document has submitted to Standardization Technical Committee of National Alkaline Batteries of Electronic Industry Information Standards of the Ministry of Industry and Information Technology of the People's Republic of China.