Accession Number:

ADB207046

Title:

PCM Thermal Control of Nickel-Hydrogen Batteries

Descriptive Note:

Final rept.

Corporate Author:

ENERGY SCIENCE LABS INC SAN DIEGO CA

Personal Author(s):

Report Date:

1993-06-01

Pagination or Media Count:

61.0

Abstract:

Thermal control is a design driver for space applications of nickel-hydrogen Ni- H2 battery systems, because excessive temperatures shorten battery cycle life. Compared with the nickel-cadmium Ni-Cd batteries they are replacing, the Ni-H2 batteries require lower operating temperatures but they generate higher heat loads. The space radiators that provide the cooling in satellites are generally sized to avoid damaging high temperatures during high-rate battery discharge. However, at other orbital phases when battery heat dissipation is low, the radiators cooling is excessive, and battery heaters are required to avoid damage by freezing. This project considers increasing the effective heat capacity of the battery to reduce the heating requirements and downsize the radiators toward the orbital average load. In principle, doubling the effective battery heat capacity in the range from -5 deg C to 5 deg C can reduce transients by 50 but increases the battery mass by only 3, assuming water is used through its phase change at 0 deg C. In practice, the reliability of the encapsulation and heat transfer are problematical. We consider innovative phase-change composite PCC design using conductive carbon fiber wick structures that perform well and appear to enable compact, reliable design. jg p9

Subject Categories:

  • Electric Power Production and Distribution
  • Inorganic Chemistry
  • Thermodynamics
  • Astronautics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE