Ford Aerospace & Communications Corporation

Charles W Koehler

Gerrit Van Ommering

Gerrit VanOmmering

Neil H Puester

The disclosed invention is a device and method for optimizing the weight and/or the heat transfer (conduction) capability of a heat transfer cylindrical sleeve. The sleeve is designed to fit around a cylindrical heat source. One particular application for this invention is where the heat source is a battery such as a metal gas battery in a satellite (where weight savings is important). Two sets of functional relationships are generated showing the relationship between the thickness of the sleeve at its top and bottom, an 'area factor' (which is directly proportional to its heat transfer capability), the material thermal conductivity, and its volume per unit length (which is directly proportional to its weight). One can specify the desired heat transfer capability of the sleeve and optimize (minimize) its weight. Conversely, one can specify the desired weight for the sleeve and optimize (maximize) its heat transfer capability. Assuming that the heat source has a uniform heat generating propensity along its cylindrical surface, the optimum shape for the sleeve is tapered with dimensions as described herein.

Heat conducting sleeve

In a method for fabricating lightweight bipolar metal-gas battery cell stacks (1), a segmented frame (21, 23) for insulating and mechanically supporting the stack (1) is fabricated of dielectric materials. Each cell (3) has associated therewith first and second frame segments (21, 23) associated with negative and positive electrodes (5, 7, respectively). Weld tabs (25, 27) are welded to the negative and positive electrodes (5, 7, respectively), and are welded together external to the cell frame (21, 23). Electrolyte is added to each cell (3), preferably as it is fabricated within the enveloping cell frame segments (21, 23). Alignment rods (34) align the stack (1) components, and assist in compression-sealing adjacent frame segments (21, 23) by means of compressing mating tongues (43) and grooves (41).

Method for making a lightweight bipolar metal-gas battery

An active cooling system (40, 41) for cooling electrochemical cells (11) that are arranged in a stack (9) in a fuel cell or battery (3). The cooling system (40, 41) comprises cooling panels (15, 16) carrying a cooling fluid that flows adjacent to, and parallel to the plane of, each cell (11). The rate of cooling fluid flow past each cell (11) is made to be substantially equal, so that each cell (11) experiences substantially the same cooling environment, adding to the longevity of the fuel cell or battery (3). This can be accomplished by equalizing the resistance to cooling fluid flow for each cooling path (12), e.g., by using pressure equalizing, monotonically increasingly sized orifices (28) in an input manifold (25). Dual cooling panels (15, 16) are preferably employed, in a counterflow mode. The panels (15, 16) may be divided into parallel channels (33). Heat pipe panels (35) containing a two-phase fluid may be used in lieu of panels (15, 16) that contain cooling fluid in a single state.

Active cooling system for electrochemical cells

A bipolar metal-gas battery cell stack (1) eliminates the heavy bipolar plates (11) of the prior art by means of locating the series electrical connections (25, 27) between oppositely polarized electrodes (5, 7) of adjacent cells (3) external to the cells (3) in a dielectric frame (21, 23). As a result, the reliability of said electrical connections (25, 27) is improved, weight is saved, and reactant gas screens (15) and electrolyte reservoirs (13) can beneficially be made of compressible lightweight materials. Electrolyte is beneficially confined within each cell (3), and secondary (overcharge) gasses are beneficially confined within each cell (3) in a region (17) proximate the positive electrode (7). A hydrophobic barrier (29) and the frame segments (21, 23) prevent intercell migration of electrolyte and secondary gasses.

Lightweight bipolar metal-gas battery

A device and method for optimizing the weight and/or the heat transfer (conduction) capability of a heat transfer cylindrical sleeve. The sleeve is designed to fit around a cylindrical heat source. One particular application for this invention is where the heat source is a battery such as a metal gas battery in a satellite (where weight savings is important). Two sets of functional relationships are generated showing the relationship between the thickness of the sleeve at its top and bottom, an 'area factor' (which is directly proportional to its heat transfer capability), the material thermal conductivity, and its volume per unit length (which is directly proportional to its weight). One can specify the desired heat transfer capability of the sleeve and optimize (minimize) its weight. Conversely, one can specify the desired weight for the sleeve and optimize (maximize) its heat transfer capability. Assuming that the heat source has a uniform heat generating propensity along its cylindrical surface, the optimum shape for the sleeve is tapered with dimensions as described herein.

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Milpitas, CA, United States of America

Charles W Koehler