A novel active cell balancing topology for serially connected Li-ion cells in the battery pack for electric vehicle applications.

In a Battery Management System (BMS), cell balancing plays an essential role in mitigating inconsistencies of state of charge (SoCs) in lithium-ion (Li-ion) cells in a battery stack. If the cells are not properly balanced, the weakest Li-ion cell will always be the one limiting the usable capacity of battery pack. Different cell balancing strategies have been proposed to balance the non-uniform SoC of cells in serially connected string. However, balancing efficiency and slow SoC convergence remain key issues in cell balancing methods. Aiming to alleviate these challenges, in this paper, a hybrid duty cycle balancing (H-DCB) technique is proposed, which combines the duty cycle balancing (DCB) and cell-to-pack (CTP) balancing methods. The integration of an H-bridge circuit is introduced to bypass the selected cells and enhance the controlling as well as monitoring of individual cell. Subsequently, a DC-DC converter is utilized to perform CTP balancing in the H-DCB topology, efficiently transferring energy from the selected cell to/from the battery pack, resulting in a reduction in balancing time. To verify the effectiveness of the proposed method, the battery pack of 96 series-connected cells evenly distributed in ten modules is designed in MATLAB/Simulink software for both charging and discharging operation, and the results show that the proposed H-DCB method has a faster equalization speed 6.0 h as compared to the conventional DCB method 9.2 h during charging phase. Additionally, a pack of four Li-ion cells connected in series is used in the experiment setup for the validation of the proposed H-DCB method during discharging operation. The results of the hardware experiment indicate that the SoC convergence is achieved at ~ 400 s.

Development of bespoke hardware and software to enable testing of a novel method of managing the charge and discharge of series-connected battery packs.

The novel feature of the method of battery management under development and testing is that routine balancing of the cells is eliminated throughout the service life of the battery pack. This requires preparation of the battery cells and configuration of the rigs in such a way as to ensure that the cells are accurately balanced on assembly and that thereafter there is no cell-to-cell variation in charge current or load at any time, measured to a low microamp level. In addition, the method requires a special charge control algorithm which was devised in order to accommodate cell-to-cell variations in capacity and dynamic response. Comprehensive experimental testing of this method, which is fully described in the associated paper (Hardy et al., 2023), required the development of hardware and software which would combine the necessary functions of a battery test rig and a battery management system capable of carrying out the special method of charge control described below. These included:•The automated control of contactors, loads and chargers to perform multiple charge/discharge cycles to predetermined patterns of current and maximum and minimum cell voltages.•Monitoring of cell voltages, current and temperature and the provision of test and diagnostic data.•Performing the safety functions of a Battery Management System to ensure that no cell was permitted to exceed limitations of current, voltage or temperature. The hardware and software were developed through three phases of testing with the operational principles (but not all the hardware and software elements) carrying over from one phase to the next.

Understanding of Crucial Factors for Improving the Energy Density of Lithium-Sulfur Pouch Cells.

Rechargeable lithium-sulfur (Li-S) batteries are the most promising next-generation energy storage system owing to their high energy density and low cost. Despite the increasing number of publications on the Li-S technology, the number of studies on real prototype cells is rather low. Furthermore, novel concepts developed using small lab cells cannot simply be transferred to high-energy cell prototypes due to the fundamental differences. The electrolyte and lithium anode excess used in small lab cells is known to have a huge impact on the cycle life, capacity, and rate capability of the Li-S system. This work analyses the performance of pouch cell prototypes demonstrating the potential and hurdles of the technology. The impact of electrolyte variations and the sulfur cathode loading are studied. The energy density of Li-S pouch cell is improved up to 436 Wh kg-1 by a combination of different approaches related to cell manufacturing, sulfur cathode optimization, and electrolyte amount adjustment.

The origin and onset of acute venous thrombus.

Under the condition of immune cell balancing function collapse, acute venous thrombosis originates from intravenous immune adhesive inflammations triggered by cells which are infected by foreign pathogenic microorganism and malignant cells. With the condition of immune cell balancing function collapse, the human body lost the function of clearing intravenous foreign pathogenic microorganism and malignant cells timely and effectively. Thus, integrins ß2 and ß3 on the membrane of white blood cells and platelets are activated to combine with the ligand fibrinogen into a reversible mesh-like structure, which is like the intravenous biological filter and acts as physical defense of the human body to prevent the cells which are infected by foreign pathogenic microorganism and malignant cells in the distal veins from flowing back to the whole body. Meanwhile, blood cells mainly red blood cells stagnate and fulfill the filter, which blocks the blood flow in the local veins and thus results in venous thrombotic diseases. People with collapsed immune cell balancing functions are the certain groups of people who will develop venous thromboembolism. Anyone who had venous thromboembolism indicates alloantigen cells in the veins, which are mainly pathogenic microorganism infected cells and malignant cells and trigger the onset of venous thromboembolism. Only under the condition of immune cell balancing function collapse, the risk factors, such as advanced age, infection, trauma, surgery, autoimmune disease, pregnancy as well as long trip syndrome, could cause venous thromboembolism.

Effect of montelukast combined with seretide in treatment of patients with asthma and its influence on balance between Th17 and Treg cells, and expression of IL-4 and IFN-γ / 中国生化药物杂志

Objective To evaluate the effect of montelukast combined with seretide in treatment of patients with asthma and its influence on balance between Th17 and Treg cells, and expression of IL-4 and IFN-γ.Methods 110 patients with asthma were randomly divided into observation group and control group, observation group of 55 cases, using montelukast combined with seretide, control group of 55 cases, using seretide,compared two groups of patients with pulmonary function changes, peripheral inflammatory factor changes and influence on Th17 and Treg cells balance. Results Before treatment, observation group and control group,FEV1 and FEV1 /FVC value was no significant difference.FEV1 and FEV1 /FVC after treatment were significantly improved compared with before treatment in two groups, differences were statistically significance (P<0.05).Between two groups, FEV1 values were significantly difference (t=8.1156, P=0.0001), FEV1 /FVC also had significant difference (t=4.8933, P=0.0001) .Before treatment, observation group and control group, IL-4 and IFN-γdid not have a statistically significant.After treatment, IL-4 and IFN-γdecreased significantly, with statistical difference compared with before treatment (P<0.05).Between two groups, IL-4 had significant difference (t=6.0273, P=0.0001), IFN-γalso had statistically significant (t=6.6042, P=0.0001).Before treatment, there was no significant difference between Th17 and Treg percentage, after 12 weeks of treatment and 24 weeks, Th17 in observation group were(0.53 ±0.02),(0.32 ±0.01), the control group were (0.78 ±0.03),(0.62 ±0.02), which had differences (P<0.05).After 12 weeks and 24 weeks,observation group Treg respectively(2.21 ± 0.22),(2.47 ±0.10),in control group were(1.50 ±0.11),(1.84 ±0.14), Treg percentage at different time after treatment, the differences had statistically significant (P<0.05).Conclusion Montelukast combined with Seretide in treating with asthma, pulmonary function of patients is obviously improved, and it can improve Th17, Treg cell.