To cope with automobile exhaust gas regulations, ISG (Idling Stop & Go) and charging control systems are applied to HEVs (Hybrid Electric Vehicle) for the purpose of improving fuel economy. These systems require quick charge/discharge performance at high current. To satisfy this characteristic, improvement of the positive electrode plate is studied to improve the charge/discharge process and performance of AGM(Absorbent Glass Mat) lead-acid batteries applied to ISG automotive systems. The bonding between grid and A.M (Active Material) can be improved by applying the Sand-Blasting method to provide roughness to the surface of the positive grid. When the Sand-Blasting method is applied with conditions of ball speed 1,000 rpm and conveyor speed 5 M/min, ideal bonding is achieved between grid and A.M. The positive plate of each condition is applied to the AGM LAB (Absorbent Glass Mat Lead Acid Battery); then, the performance and ISG life characteristics are tested by the vehicle battery test method. In CCA, which evaluates the starting performance at -18 oC and 30 oC with high current, the advanced AGM LAB improves about 25 %. At 0 oC CA (Charge Acceptance), the initial charging current of the advanced AGM LAB increases about 25 %. Improving the bonding between the grid and A.M. by roughening the grid surface improves the flow of current and lowers the resistance, which is considered to have a significant effect on the high current charging/discharging area. In a Standard of Battery Association of Japan (SBA) S0101 test, after 300 A discharge, the voltage of the advanced AGM LAB with the Sand-Blasting method grid was 0.059 V higher than that of untreated grid. As the cycle progresses, the gap widens to 0.13 V at the point of 10,800 cycles. As the bonding between grid and A.M. increases through the Sand Blasting method, the slope of the discharge voltage declines gradually as the cycle progresses, showing excellent battery life characteristics. It is believed that system will exhibit excellent characteristics in the vehicle environment of the ISG system, in which charge/discharge occurs over a short time.

The performance characteristics of a lead acid battery are investigated with the content of Sodium Perborate Tetrahydrate (SPT, NaBO3·4H2O) in a positive plate active material. SPT, which reacts with water to form hydrogen peroxide, is applied as an additive in the positive plate active material to increase adhesion between the substrate (positive plate) and the active material; this phenomenon is caused by a chemical reaction on the surface of substrate. A positive plate with the increasing content of SPT is prepared to compare its properties. It is confirmed that the oxide layer increases at the interface between the substrate and the active material with increasing content of SPT; this is proven to be an oxide layer through EDS analysis. Battery performance is confirmed: when SPT content is 2.0 wt%, the charging acceptance and high rate discharge properties are improved. In addition, the lifetime performance according to the Standard of Battery Association of Japan (SBA) S0101 test is improved with increasing content of SPT.

In this study, an experiment is performed to recover the Li in Li2CO3 phase from the cathode active material NMC (LiNiCoMnO2) in waste lithium ion batteries. Firstly, carbonation is performed to convert the LiNiO, LiCoO, and Li2MnO3 phases within the powder to Li2CO3 and NiO, CoO, and MnO. The carbonation for phase separation proceeds at a temperature range of 600oC~800oC in a CO2 gas (300 cc/min) atmosphere. At 600~700oC, Li2CO3 and NiO, CoO, and MnO are not completely separated, while Li and other metallic compounds remain. At 800 oC, we can confirm that LiNiO, LiCoO, and Li2MnO3 phases are separated into Li2CO3 and NiO, CoO, and MnO phases. After completing the phase separation, by using the solubility difference of Li2CO3 and NiO, CoO, and MnO, we set the ratio of solution (distilled water) to powder after carbonation as 30:1. Subsequently, water leaching is carried out. Then, the Li2CO3 within the solution melts and concentrates, while NiO, MnO, and CoO phases remain after filtering. Thus, Li2CO3 can be recovered.

In this study, a finite element analysis approach is proposed to predict the fluid-structure interaction behavior of active materials for lithium-ion batteries (LIBs), which are mainly composed of graphite powder. The porous matrix of graphite powder saturated with fluid electrolyte is considered a representative volume element (RVE) model. Three different RVE models are proposed to consider the uncertainty of the powder shape and the porosity. Pwave modulus from RVE solutions are analyzed based on the microstructure and the interaction between the fluid and the graphite powder matrix. From the results, it is found that the large surface area of the active material results in low mechanical properties of LIB, which leads to poor structural durability when subjected to dynamic loads. The results obtained in this study provide useful information for predicting the mechanical safety of a battery pack.

The effects of the mixing of an active material and a conductive additive on the electrochemical performance of an electric double layer capacitor (EDLC) electrode were investigated. Coin-type EDLC cells with an organic electrolyte were fabricated using the electrode samples with different ball-milling times for the mixing of an active material and a conductive additive. The ball-milling time had a strong influence on the electrochemical performance of the EDLC electrode. The homogeneous mixing of the active material and the conductive additive by ball-milling was very important to obtain an efficient EDLC electrode. However, an EDLC electrode with an excessive ball-milling time displayed low electrical conductivity due to the characteristic change of a conductive additive, leading to poor electrochemical performance. The mixing of an active material and a conductive additive played a crucial role in determining the electrochemical performance of EDLC electrode. The optimal ball-milling time contributed to a homogeneous mixing of an active material and a conductive additive, leading to good electrochemical performance of the EDLC electrode.

Background : This study was carried out to investigate the antioxidative activity and active ingredients of Glehenia littoralis through purification process. Methods and Results : Above-ground and below-ground parts of Glehenia littoralis, dried in Gangneung, were purchased, crushed, sonicated for 2 hours in 100% ethanol, filtered and concentrated. Above-ground part of G.littoralis which is more effective higher antioxidant effect than below-ground part in 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. Was used to extract the above-ground part of the solvent fraction according to polarity (hexane, ethyl acetate, water) and HP20 column separation (0, 30, 60, 100% EtOH). Using the fraction was the DPPH assay with high-performance liquid chromatography (HPLC) analysis. Comparing the antioxidant efficacy with that of fraction isolated from Glehenia littoralis extract. Hexane, water layer and 100% EtOH fraction showed lower efficacy than Glehenia littoralis extract. 60% EtOH fraction showed more than 8 times higher efficacy. In order to compare the components according to their efficacy, HPLC analysis was carried out. The fraction (hexane, water layer, 100% EtOH fraction) which showed low antioxidative activity confirmed imperatoin and nonpolar compound, the fraction (ethyl acetate, 60% EtOH fraction) showed a higher antioxidant activity was confirmed 2 flavonoid and scopoletin. Conclusion : Glehenia littoralis extract showed low antioxidant activity of 893 ㎍/㎖ with IC50 of DPPH assay. However, it showed an increase of antioxidant activity by IC50 of 115㎍ /㎖ of DPPH assay of 60% EtOH fraction by fractionation and separation. Through HPLC analysis, the active ingredient, scopoletin and two flavonoids were identified.

Background : Korean mountain ginseng(Panax ginseng C.A. Meyer) are difficult to clinically apply because of its scarcity and high cost. Advances in plant biotechnology have made it possible to produce mountain ginseng extracts on a large scale using adventitious root cultures in bio-reactors. This study investigated the variations of ginsenoside compounds composition and biological activities of wild ginseng adventitious roots by fermentation process. Methods and Results : Wild ginseng adventitious roots with five days fermentation using four strain of bacteria(Leuconostoc mesenteroides(KACC 15744), Bacillus circulans(KACC 15822), Bacillus licheniformis(KACC 15823), Bacillus subtilis subsp. inaquosorum(KACC 17047)). Ginsenoside contents was analysed by using HPLC. To examine the antioxidant activity associated with biological functions, radical scavenging analyses DPPH, ABTS and SOD-like activity analyses were conducted. The total phenolic and flavonoid contents were evaluated to determine the antioxidant activity increment. The result showed increased total ginsenoside contents by fermentation process. In particular, B. licheniformis showed the highest ginsenoside contents. Regarding ginseng fermented with B. licheniformis, values of 70.6 ± 1.4%, 44.3 ± 1.7%, and 88.4 ± 1.3% were measured using DPPH, ABTS, and SOD-like antioxdiant activity analyses, respectively. The total phenolic contents in ginseng fermented with B. licheniformis was 184.5 ± 0.9 ㎍·GAE/㎖, and the total flavonoid contents was 108.5 ± 1.8 ㎍·QE/㎖ in ginseng fermented with L. mesenteroides. Conclusion : The high activity of β-glucosidase was selected bacteria. The four types of lactic acid bacteria examined, the use of B. licheniformis to ferment ginseng resulted in greatest increase in biological activities and ginsenoside contents.