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Other TitleHigh-Reliable Single-Switch Equalization Charger for Series-Connected Energy Storage Cells
Author(jpn)鵜野, 将年; 田中, 孝治
Author(eng)Uno, Masatoshi; Tanaka, Koji
Author Affiliation(jpn)宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS); 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)
Author Affiliation(eng)Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS); Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)
Issue Date2011-05-17
PublisherInstitute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)
Publication title30th ISAS Space Energy Symposium
Publication date2011-05-17
AbstractSeries connections of energy storage cells such as electric double-layer capacitors (EDLCs) and lithium-ion cells suffer from voltage imbalance originating from nonuniform cell properties such as capacitance, internal impedance, self discharge rate, and environmental temperature. Such voltage imbalance not only causes premature degradation but also leads to a decrease in available energies. Voltage equalizers are usually used to mitigate or even eliminate such voltage imbalance to prolong cycle lives and to maximize available energies of the cells. However, conventional topologies based on traditional dc-dc converters require numerous switches or transformers as the number of series connection increases. Therefore, their costs and complexity tend to increase, and their reliability decreases. This paper proposes a novel high-reliable single-switch equalization charger for series-connected energy storage cells.The proposed equalization charger consists of single switch and multi-stacked circuits composed of passive components such as diodes, inductors, and capacitors. And the diodes in the proposed equalization charger during discharging periods also can be utilized as bypass diodes which are usually connected to the cells in parallel in spacecraft battery systems. Therefore, the complexity of the battery system using the proposed equalization charger can be reduced dramatically as compared with conventional spacecraft battery systems. In addition, the switch in the proposed equalization charger is not directly connected to the cells. Hence, any failures of the switch never affect the cells, so that the reliability of this equalization charger is considered higher.Experimental charge tests using a prototype were performed for 4-series-connected EDLC cells whose initial voltages were intentionally imbalanced. A CIC-CV (Constant Input Current-Constant Voltage) charge scheme, which controls an input current and one of the cell voltages, was used for the experimental charge tests.Experimental results demonstrated that the proposed equalization charger can charge the series-connected cells preferentially in the order of their increasing cell voltage, and all the cells eventually can be charged to a uniform voltage level. The experimental charge test was also performed for the series-connected EDLCs containing an open-failure cell. The cells were uniformly charged in spite of having the open-failure cell.
DescriptionPhysical characteristics: Original contains color illustrations
Meeting Information: The thirtieth Space Energy Symposium (February 25, 2011. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan
Note: One CD-ROM
形態: カラー図版あり
会議情報: 第30回宇宙エネルギーシンポジウム(2011年2月25日, 宇宙航空研究開発機構宇宙科学研究所相模原キャンパス), 相模原市, 神奈川県
形態: CD-ROM1枚
Document TypeConference Paper
JAXA Categoryシンポジウム・研究会

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