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Compact Electronic Circuit and Battery for Remote Sensing in High Temperature Environments

IP.com Disclosure Number: IPCOM000117403D
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 207K

Publishing Venue

IBM

Related People

Guidotti, D: AUTHOR [+3]

Abstract

Data acquisition and transmission from a high temperature environment generally requires bulky thermal insulation to protect electronic components and batteries. The survival time of thermally insulated probes depends on ambient temperature, type and thickness of the thermal insulation, and the maximum operating temperature of its components. Given spatial restrictions and high ambient temperatures, it is not always possible to achieve desirable sampling times using known thermal insulation materials and electronic components that are presently available commercially. Molten salt batteries that can operate at high temperatures are available commercially, but are bulky.

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Compact Electronic Circuit and Battery for Remote Sensing in High
Temperature Environments

      Data acquisition and transmission from a high temperature
environment generally requires bulky thermal insulation to protect
electronic components and batteries.  The survival time of thermally
insulated probes depends on ambient temperature, type and thickness
of the thermal insulation, and the maximum operating temperature of
its components.  Given spatial restrictions and high ambient
temperatures, it is not always possible to achieve desirable sampling
times using known thermal insulation materials and electronic
components that are presently available commercially.  Molten salt
batteries that can operate at high temperatures are available
commercially, but are bulky.  Commercially available, compact
batteries have an upper temperature limit of 200 degree C, and
commercially available transistors and other junction electronic
components generally operate at temperatures under 200 degree C.

      Exploratory junction devices which can operate at high
temperatures have been reported and demonstrated from time to time
and can be used to construct electronic circuits that can operate at
high temperatures.  GaP junction devices (1) have been reported to
operate up to 450 degree C, while those based on GaAs(2) have been
shown to operate up to 400 degree C.  SiC tunnel diodes (3) have been
demonstrated to operate up to 500 degree C.  Therefore, in principle,
electronic circuits that can function normally at high temperatures
and are capable of data acquisition and transmission from hostile
temperature environments can be constructed, provided a suitable
power source is available.

      Exploratory power sources which are cheap, compact, safe,
rechargeable, and have sufficient energy density to power a small
electronic package, such as a transmitter circuit, for several hours
at 350 degreeC have also been reported (4,5,6).  Of particular
interest, as a starting point of reference, are solid state batteries
that are based on Li salts.  These are of the type (5): Li sub 4.4 Si
divslash SLA divslash TiS sub 2, C, SLA where SLA = Li Iota bullet
'Al' sub 2 O sub 3.  This system is used as an example to demonstrate
the type of battery which we consider ideal as a low power source for
data transmission electronics.  These type of solid state batteries
are desirable because they are entirely solid and no internal
over-pressure can occur even at over-temperatures where some of the
solids can melt.  The low profile cell geometry is particularly
suited for miniature circuits.  This type of battery is rechargeable,
has a very long shelf life, a sufficiently high EMF, and the stored
energy density is sufficiently high so that a nominal "button"-type
cell can power a low drain electronic circuit of the type described
below for several hours.  However, because TiS sub 2 melts at 350
degree C, and because the internal resistance of this t...