Low temperature (-15°C ) operational test of the battery package in the Antarctic penetrator

• Main Author: Kazuo Shibuya
• Format: Article in Journal/Newspaper
• Language: English
• Published: National Institute of Polar Research 2004
• Subjects: geo; Antarctic; The Antarctic; Antarc*; Ice Sheet
• Online Access: https://doi.org/10.15094/00009298; https://doaj.org/article/9620540b883c4e61ba17649df41a2f2a

In order to perform seismic explosion experiments in the crevassed area of the Antarctic ice sheet, a seismometer deployable from the air is desired. We have developed such a helicopter-deployable system (called the Antarctic penetrator), which consists of a Ground System Segment (GSS) and an Automatic Data Collection Segment (ADCS). Its test operation by the 43rd Japanese Antarctic Research Expedition (JARE-43) was, however, not successful. The reason was found to be leakage of 3.6mA current from the battery package during transportation. In order to re-examine the life time of the battery package under an operational environment at -15°C , we tested the lithium thionyl chloride batteries in a laboratory cryostat. The operational scenario is as follows. After initialization of the GSS, it enters into a sleep mode of 20days duration. At the 21st day, the GSS becomes awake and enters into the switching stage of 12 hours-awake and 12 hours-sleep modes for the following 20-30days. During the awake-period, the radio-telemeter module becomes active and transmits commands and/or recovers stored data to the ADCS once or twice a day. The current consumption in the sleep-mode was 60mA, while it was 135mA during the awake-mode. The current consumption attained about 230mA during the active mode, with an associated voltage fall of 0.5V. With 8 TL5930 cells in parallel and 2 in serial (cell capacity 19 Ah; Tadiran Co., Ltd.), operation was successful with a life time of more than 50days. The life limit can be predicted from the time when the voltage becomes lower than 4.8V in the active mode. It was possible to recover the GSS-stored 4 event data (48Kbytes) to the ADCS in about 40 s fifty times during the above 50days.