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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Improved silver-zinc battery-terminal seals

Development of battery terminal seal for sealing electrolyte for periods of three to five years is discussed. Operating conditions of battery are defined. Components of electrolyte seal and method of production are reported. Schematic diagrams of device are included.

Snider, W. E.↗
NASA NTRS1974

Rechargeable, silver-zinc battery conditioner/monitor unit and state-of-charge indicator

Unit automatically charges batteries to desired state-of-charge levels, monitors functional battery parameter data both on meters and printer, and automatically activates alarm in event of battery malfunctions. Unit consists of state-of-charge indicator panel, control panel, monitor panel, power panel, charging-current power supply, and load panel.

Thomas, C. E.↗
NASA NTRS1973

Study of oxygen gas production phenomenon during stand and discharge in silver-zinc batteries

The effects of a number of cell process and performance variables upon the oxygen evolution rate of silver/silver oxide cathodes are studied to predict and measure the conditions which would result in the production of a minimum of oxygen. The following five tasks comprise the study: the design and fabrication of two pilot test cells to be used for electrode testing; the determination of the sensitivity and accuracy of the test cell; the determination of total volumes and rates of generation by cathodes of standard production procedures; the construction of a sequential test plan; and the construction of a series of positive formation cells in which formation process factors can be controlled.

Source record↗
NASA NTRS1973

Study of the zinc-silver oxide battery system

Theoretical and experimental models for the evaluation of current distribution in flooded, porous electrodes are discussed. An approximation for the local current distribution function was derived for conditions of a linear overpotential, a uniform concentration, and a very conductive matrix. By considering the porous electrode to be an analog of chemical catalyst structures, a dimensionless performance parameter was derived from the approximated current distribution function. In this manner the electrode behavior was characterized in terms of an electrochemical Thiele parameter and an effectiveness factor. It was shown that the electrochemical engineering approach makes possible the organizations of theoretical descriptions and of practical experience in the form of dimensionless parameters, such as the electrochemical Thiele parameters, and hence provides useful information for the design of new electrochemical systems.

Nanis, L.↗
NASA NTRS1975

Charge exchange in zinc-neon

Excitation of the 4d and 5p levels of Zn+ by charge exchange bewteen Ne+ and Zn was investigated. From measured electron temperature and line intensity ratios it was concluded that charge exchange is the dominate mechanism for populating the 4d2D5/2 level of Zn+. Comparison of Zn-Ne and Zn-Ar results imply the same conclusion. No evidence for charge exchange as the dominant pumping mechanism for the 5p2Pl/2, 5p2P3/2, or 4d2D3/2 levels was obtained.

Chubb, D. L.↗
NASA NTRS1976

Functioning of inorganic/organic battery separators in silver-zinc cells

The results of three experimental studies related to the inorganic/organic battery separator operating mechanism are described: saponification of the plasticizer, resistivity of the simulated separators, and zincate diffusion through the separators. The inorganic/organic separator appears to be a particular example of a general class of ionic conducting films composed of inorganic fillers and/or substrates bonded together by an organic polymer containing an incompatible plasticizer that may be leached by the electrolyte. The I/O separator functions as a microporous film of varying tortuosity with essentially no specific chemical inhibition to zincate diffusion.

Philipp, W. H.↗
NASA NTRS1976

Impedance of silver oxide-zinc cells

Over 100 sealed AgO-Zn cells were subjected to prolonged periods of storage over a range of temperatures and storage modes including open circuit, trickle charge, and float charge. Impedances of these cells were monitored throughout, and at the end of the storage period their transient voltage characteristics were observed at the onset of discharge. Results revealed that the impedances of these cells tended to increase with storage time; the magnitude of the impedance rise was dependent primarily on temperature and to a lesser degree on storage mode. Typical values for 50 A-hr cells were usually less than 100 mohm immediately after activation and from 1 to 30 ohm after 6-10 months of storage. Transient voltages of these cells droped sharply during the first msec of discharge and then rose to a stablized value during the following few seconds. The magnitude of the initial drop and the stabilized voltage values were found to be related to impedance but not in a linear manner. The magnitude and duration of the low transient voltages may be unacceptable in some applications of these cells. The impedance variations are attributed to changes occurring at the positive electrode.

Frank, H. A.↗
NASA NTRS1975

Charge exchange in zinc-neon

Excitation of the 4d and 5p levels of Zn(+) by charge exchange between Ne(+) and Zn was investigated. From measured electron temperature and line intensity ratios it was concluded that charge exchange is the dominant mechanism for populating the 4d 2D5/2 level of Zn(+). Comparison of Zn-Ne and Zn-Ar results imply the same conclusion. No evidence for charge exchange as the dominant pumping mechanism for the 5p 2P1/2, 5p 2P3/2, or 4d 2D3/2 levels was obtained.

Chubb, D. L.↗
NASA NTRS1977

Cycle life characteristics of sealed silver-zinc cell with inorganic separator

Two batteries containing 18 cells have been cycling in a simulated synchronous (24-hour) orbit for over a year at 40% depth of discharge at 22 C. One battery is under individual cell monitoring and control and the other battery is controlled at the battery level. The battery with individual cell monitoring and protection has performed over 350 cycles with no sign of failure. The battery without individual cell protection failed at 270 cycles from failure to remain above the specified minimum discharge voltage. A significant conclusion is that the sealed Ag-Zn cells manufactured with the inorganic separator material have demonstrated their capability to cycle at a fairly high depth of discharge and are worthy of consideration in short life synchronous orbit applications.

Lear, J. W.↗
NASA NTRS1978

Determination of liquid-phase immiscibility in the lead-zinc system

A number of different techniques in the past have yielded inconsistent equilibrium measurements of immiscibility in the Pb-Zn system above 600 C. Accurate differential thermal analysis (DTA) measurements were performed on well-homogenized samples of high-purity Pb-Zn, and they indicate that the immiscibility curve is higher than previously accepted for Zn compositions between 20 and 70 at. %. The maximum deviations observed correspond to about 20 C. Below 600 C the DTA results agree with previous results.

Trahan, J. F.↗
NASA NTRS1978

Preferential enhancements of the solar flare-accelerated nuclei carbon to zinc from about 20-300 MeV/nucleon

IMP 8 satellite measurements with a charged-particle telescope are examined which show that three large solar flares in late 1977 displayed preferential enhancements of abundances from C through Fe at energies of about 20 to 400 MeV/nucleon. It is found that the differential energy spectra of C, O, Mg, Si, and Fe, as well as protons and helium, are best fitted by power laws in energy per nucleon or rigidity with an index of 2.3 + or - 0.2, that the spectra of most of the even-Z nuclei have essentially the same slope, and that all the enhancements were independent of energy in the range from 20 to 300 MeV/nucleon. A plot of enhancement factor vs. Z is presented which clearly demonstrates the preferential enhancement of abundances with increasing Z in one of the solar flares, where the nuclei reached such high energies that they must have escaped the corona fully stripped of electrons. Implications for theories of solar-flare acceleration of the nuclei are considered.

Dietrich, W. F.↗