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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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102 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Cycle life status of SAFT VOS nickel-cadmium cells

The SAFT prismatic VOS Ni-Cd cells have been flown in geosynchronous orbit since 1977 and in low earth orbit since 1983. Parallel cycling tests are performed by several space agencies in order to determine the cycle life for a wide range of temperature and depth of discharge (DOD). In low Earth orbit (LEO), the ELAN program is conducted on 24 Ah cells by CNES and ESA at the European Battery Test Center at temperatures ranging from 0 to 27 C and DOD from 10 to 40 percent. Data are presented up to 37,000 cycles. One pack (X-80) has achieved 49,000 cycles at 10 C and 23 percent DOD. The geosynchronous orbit simulation of a high DOD test is conducted by ESA on 3 batteries at 10 C and 70, 90, and 100 percent DOD. Thirty-one eclipse seasons are completed, and no signs of degradation have been found. The Air Force test at CRANE on 24 Ah and 40 Ah cells at 20 C and 80 percent DOD has achieved 19 shadow periods. Life expectancy is discussed. The VOS cell technology could be used for the following: (1) in geosynchronous conditions--15 yrs at 10-15 C and 80 percent DOD; and (2) in low earth orbit--10 yrs at 5-15 C and 25-30 percent DOD.

Goualard, Jacques↗
NASA NTRS1994

Determination of thermal properties of commercial Ni-MH cells

The test objectives were to evaluate the electrical and thermal performance of commercial Ni-MH cells, evaluate the effectiveness of commercial charge control circuits, assess the abuse tolerance of these cells, and correlate performance and abuse tolerances to cell design via disassembly. Design objectives were to determine which cell designs are most suitable for scale-up and to guide the design of future shuttle and space station based battery chargers. Results, displayed in viewgraph format, include: reflex charging with ICS circuit resulted in premature charge termination; Ni-MH cells appear very tolerant to overcharge at low rates; Enstore's charger is more electrically and thermally efficient at high rates; and Ni-MH cycles much more efficiently than Ni-Cd with the delta-V/delta-t termination.

Darcy, Eric C.↗
NASA NTRS1996

First principles nickel-cadmium and nickel hydrogen spacecraft battery models

The principles of Nickel-Cadmium and Nickel-Hydrogen spacecraft battery models are discussed. The Ni-Cd battery model includes two phase positive electrode and its predictions are very close to actual data. But the Ni-H2 battery model predictions (without the two phase positive electrode) are unacceptable even though the model is operational. Both models run on UNIX and Macintosh computers.

Timmerman, P.↗
NASA NTRS1997

Effect of Storage on Performance of Super Nickel-Cadmium Cells

A study was undertaken to examine the capacity maintenance features of SUPER nickel-cadmium cells when stored for extended periods to determine whether the features change when the same kinds of positive plates as that used in nickel-hydrogen cells are used, The cells maintained their capacity when stored at 0 C in the discharged state and at 0 C in the charged state by continuously trickle charging. There was a capacity loss when stored in the open-circuit condition at 28 C. A cycling test at 17% depth of discharge for 2400 cycles using cells stored at various conditions showed that cells maintained good end of discharge voltage regardless of their storage history. However, the EOD voltages of stored cells were lower by 10 mV compared to those of fresh cells. The capacity at the end of the cycling test decreased for the stored cells by 2-7 Ah. The storage related capacity loss is lower for SUPER Ni-Cd cells compared to that of Ni-H2 cells containing a hydrogen precharge. The results suggest the pivotal role of hydrogen pressure in the capacity loss phenomenon.

Vaidyanathan, Hari↗
NASA NTRS1999

Electrical and Thermal Characteristics of Lithium-Ion Cells

The 18,650 type lithium ion cells are characterized by a cell resistance of 130 mOmega, capacity of 1.27 Ah at 25 C, and a mid-discharge voltage of 3.6 V. The capacity loss in the 72-hour stand test was 3.39%. The heat dissipation properties were determined by a radiative calorimeter. During charge, initial endothermic cooling and subsequent exothermic cooling beyond 55% state- of-charge were observed. At C/2 rate of discharge (which is considered medium rate), the heat dissipated was 17 mW/cu cm. The heat dissipation profile during discharge is also unique in the presence of a minimum that is different from that observed for Ni-Cd, Ni-MH, and Ni-H2 cells.

Rao. Gopalskrishna M.↗
NASA NTRS1999

Electrical and Thermal Characteristics of Lithium-Ion Cells

The 18650 type lithium ion cells are characterized by a cell resistance of 130 m Omega, capacity of 1.27 Ah at 25C, and a mid-discharge voltage of 3.6 V. The capacity loss in the 72-hour stand test was 3.39 percent. The heat dissipation properties were determined by a radiative calorimeter. During charge, initial endothermic cooling and subsequent exothermic cooling beyond 55 percent state-of-charge were observed. At C/2 rate of discharge (which is considered medium rate), the heat dissipated was 17 mW/cc. The heat dissipation profile during discharge is also unique in the presence of a minimum that is different from that observed for Ni-Cd, Ni-MH, and Ni-H2 cells.

Vaidyanathan, Hari↗
NASA NTRS2002

Performance of Li-Ion Cells Under Battery Voltage Charge Control

Li-ion cells manufactured by YTP, SAFT, and MSA have completed 6714, 6226, and 3441 cycles, respectively. An increase in the charge voltage limit was required in all cases to maintain the discharge voltage. SAFT and MSA cells were capable of cycling at -10 C and 0 C with an increase in the charge voltage limit, whereas Yardney cells could not be cycled. Reconditioning improved the discharge voltage of SAFT and MSA cells; it is important to note that the effect has been temporary as in Ni-H and Ni-Cd batteries. It was demonstrated that the charge operation with VT clamp at battery rather than at cell level is feasible. Continuation of testing depends on the health of the cells and on the funding situation.

Vaidyanathan, Hari↗
NASA NTRS1996

Modeling of Nickel Hydroxide Electrode Containing Multiple Phases

Mathematical models of alkaline rechargeable nickel cell systems (e.g., Ni-Cd, Ni-H(sub 2) and Ni-MH) have so far been developed based on the assumption that the active material at Ni electrode exists primarily in a single phase as Beta-NiOOH -- Beta-Ni(OH)(sub 2), despite enough experimental evidence for the second phase, i.e., Gamma-NiOOH -- Alpha-Ni(OH)(sub 2), especially under conditions of extended coverage. Here, we have incorporated the additional couple of Gamma-NiOOH -- Alpha-Ni(OH)(sub 2) into the modeling of the Ni electrode.

rechargeable cells alkaline cells alkaline recharg↗
NASA NTRS2000

Design of a 10.8 kWh, 28V Ni-MH Battery Using Commercial Ni-MH Cells

This paper describes the design of a 10.8 kWh, 28V, Ni-MH battery using commercial off-the shelf (COTS) 4/3A Ni-MH cells for the X-38 vehicle, an experimental version of the Crew Return Vehicle (CRY). This will be an autonomous vehicle that will enable International Space Station crews to return to earth in the event of a medical, or other, emergency. The X-38 will be powered by 3 batteries: a 32 V primary battery, which will power the vehicle avionics for up to 7 hours for a loiter and de-orbit phase of the descent; a 28 V Ni-MH battery which will take over for the primary battery after de-orbit until landing, and a 270V Ni-Cd battery, which will be used to power electromechanical actuators and the winches controlling a parachute for landing.

Hellen, Robert M.↗
NASA NTRS1998

Electrolytes for Low Temperature Lithium-Ion Cells

Lithium-ion rechargeable batteries have been demonstrated to have high energy density, high voltage, and excellent cycle life which make this technology more attractive than competing systems such as Ni-Cd and Ni-H2.

Lithium-Ion↗
NASA NTRS1996

Application of First Principles Model to Spacecraft Operations

Previous models use a single phase reaction; cycled cell predicts cannot be met with a single phase; interphase conversion provides means for film aging; aging cells predictions display typical behaviors: pressure changes in NiH² cells; voltage fading upon cycling; second plateau on discharge of cycled cells; negative limited behavior for Ni-Cds.

batteries electrodes First Principles Model Ni-Cd ↗