Abstract:
A cell has a body containing at least one electroactive material. The body has both a positive electrical connecting means and a negative electrical connecting means on each of opposite ends of said body. Each of the negative and positive electrical connecting means is positioned such that the cell can be alternatively directly connected electrically in series or in parallel to form a battery power source.

Description:
FIELD OF THE INVENTION 
     The present invention relates to batteries and specific means to enable separate cells to be electrically connected alternately in series or in parallel. 
     BACKGROUND OF THE INVENTION 
     Cylindrical, &#34;flashlight type&#34;, battery cells are generally constructed with a positive electrode connection on one end and a negative electrode connection on the opposite end. When placed end-to-end, these batteries are connected in series. For example, if two C or D size batteries (1.5 volts each) are connected end-to-end, a net voltage potential of 3 volts is realized. 
     There are applications where a lower voltage (e.g., 1.5 net volts with two 1.5 volt cells), higher coulombic capacity, and higher discharge rate may be desirable. Further, improvements in the art have resulted in 3 volt cells, such as are provided by the Li/MnO 2  and Li/CF x  couples. It would be desirable if these higher voltage cells could be used in battery operated devices designed for 1.5 volt cells in series without making any modifications to such devices. The uses described hereinabove require means for connecting the cells together in parallel. 
     SUMMARY OF THE INVENTION 
     The present invention provides means for using cells optionally connected in parallel, or in series when placed end-to-end. Advantageously, no modification of any device external to the battery cells is required. When the cell is configured to provide either series or parallel electrical connection, changing from one to the other merely requires changing the relative rotational orientation of adjacent cells. 
     Briefly stated, the invention provides cells that can be electrically connected in parallel, although the cells are stacked in a series (i.e., end-to-end) configuration. Parallel-only connection can be provided, or parallel/series dual capability. With dual capability, the invention provides battery cells that can be connected in series or parallel by a relative rotation between adjacent cells in a stack. 
     Six embodiments are provided. The first embodiment uses a central, approximately rectangular pin and socket. Both the pin and socket have contacts for positive and negative electrodes. Switching from series to parallel connection is accomplished by rotating one cell 180° about its axis relative to the other cell (See FIGS. 1 through 3). 
     The second embodiment of the invention uses a central and two peripheral pins with matching sockets (See FIGS. 4 and 5). Switching from series to parallel is accomplished in the same way as with the first embodiment. 
     The third embodiment uses a central electrode pin and socket and peripheral prongs and sockets located 180° apart (See FIG. 6). Switching from series to parallel connection is accomplished in the same way as with the first embodiment. 
     The fourth embodiment uses a central electrode pin and socket and peripheral prongs and sockets. The prongs are located 90° apart and the peripheral sockets are located in three quadrants (See FIG. 7). Switching from series to parallel is accomplished by rotating one cell 90° about its axis relative to the other cell. 
     The fifth embodiment is exclusively a parallel-connect type of cell that uses a central positive electrode pin surrounded by an annular negative electrode plate on one end and a corresponding positive electrode socket and negative electrode surface on the other end (See FIG. 9). Aligning the cells in series in a stack results in parallel electrical connection between the cells. 
     The sixth embodiment is exclusively a parallel-connect type of cell which uses a central dual-electrode pin and dual electrode socket (See FIG. 10). Aligning the cells in series in a stack results in parallel electrical connection between the cells. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more fully understood and further applications will become apparent when reference is made to the following detailed description of the preferred embodiments of the invention and the accompanying drawings, in which: 
     FIGS. 1a and 2 are side views of a battery incorporating a first embodiment of the invention wherein a central dual electrode pin is used; 
     FIGS. 1b and 1c are side views broken away from the battery shown in FIG. 1, to illustrate series and parallel connections, respectively; 
     FIGS. 3a-3c are diagrammatic drawings depicting an alternate pin and socket design for the preferred embodiment; 
     FIGS. 4 and 5a-5b are side views of a battery incorporating an alternate embodiment of the invention wherein a central pin and two peripheral pins are used; 
     FIGS. 6a-6d are diagrammatic drawings depicting yet another alternate embodiment of the invention wherein plate-type prong connectors are used. 
     FIGS. 7a-7d are diagrammatic drawings depicting yet another alternate embodiment of the invention wherein plate-type prong connectors are used; 
     FIG. 8 is a side view of the first embodiment with the addition of a removable locating pin that can be used to either permit parallel or series connection only unless removed; 
     FIG. 9 is a side view depicting another embodiment of the invention which is a parallel-connection-only type of cell; and 
     FIG. 10 is a side view depicting yet another parallel-connection only embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Six embodiments of the invention are described herein, and are illustrated by the drawings. 
     Referring to FIG. 1a of the drawings, a battery incorporating the preferred embodiment of the invention uses a central two-electrode pin 7, on one end and a two electrode socket 8 on the opposite end. The surface between positive electrode 1 and negative electrode 2 is insulated, as well as the three adjacent exterior sides of the negative electrode 2, to minimize the potential for shorting the battery. The side of the negative electrode 2 opposite the positive electrode 1 is uninsulated. The two electrode socket 8 is configured to receive the two electrode pin 7 and has a negative electrode surface 3 and positive electrode surface 4 as well as nonconducting surfaces shown cross-hatched. 
     When used by itself or when the cell is on either end of a stack of cells, the positive electrode 1 is the contact on one end and a negative surface 5 is the contact on the opposite end. In the embodiment shown, the battery ends are suited for conventional applications without modification to electronic devices typically used therewith. 
     The pin 7 is squared to prevent relative rotation once the batteries are connected. Further, it is tapered to improve the surface pressure and thus electrical contact. 
     The connection between the cells can be adjusted for series or parallel connection as follows. For a series connection, shown in FIG. 1b, the pin 7 is inserted into the socket 8 with the positive electrode 1 against the negative side 3 of the socket 8. The negative electrode 2 is not in electrical contact with the adjacent battery, but is disposed against a nonconducting surface 6. Thus, the stacked cells are connected in series. 
     For a parallel connection, shown in FIG. 1c, the pin 7 is rotated 180° relative to the socket 8 with respect to the position for the series connection. The negative electrode 2 is in electrical contact with the negative surface 3 of the socket 8 and the positive electrode 1 is in electrical contact with the positive surface 4 of the socket 8. Thus, stacked cells are connected in parallel. 
     In use, the present invention permits significant flexibility in matching voltage requirements and optimizing battery life (e.g., by connecting higher voltage batteries in parallel rather than lower voltage batteries in series). Advantageously, four 3-volt cells in a stack can be connected to achieve a total potential of 3, 6, 9, or 12 volts. The 3, 6 and 12 volt configurations are preferred. 
     FIG. 2 shows typical details of cell construction. The sides and top and bottom of the metallic battery encasement can 9 are negative (as in conventional cylindrical flashlight batteries), except for regions of pin 7 and socket 8, which are positive and are separated from the can by insulators 10. Electrical connection between the positive electrode of pin 7, the positive electrode of socket 8, and the positive cell electrode 11 is via an insulated ribbon or wire connection 26. A plastic film 12 is used as a surface layer on the battery to provide electrical insulation. 
     An alternate pin and socket design in illustrated in FIG. 3 for the preferred embodiment. FIG. 3a shows the alternate pin 22 and 3b shows pin 22 cut on Section A--A. The entire top surface 13 of pin 22 is positive, as well as section 14, which includes two adjacent quadrants of pin 22. One quadrant 15 of pin 22 is negative and the remaining quadrant 16 is neutral. The negative quadrant 15 is separated from the positive section 14 of pin 22 and the top surface 13 thereof by an insulating layer 17. The bottom 18 of the socket 23 is neutral. The side and half sides 19 of socket 23 are negative. The sides 20, 21 for the other two quarters of the socket 23 are neutral and positive, respectively. 
     When the cells are connected in series, the positive section 14 of pin 22 is inserted in contact with the negative section 19 of the socket 23. The negative section 15 of the pin 22 is against the neutral socket walls 20 and is thus not in electrical contact. When the cells are connected in parallel, the pin is rotated 180° (relative to the socket 23) from the series orientation. Thus, the positive section 14 of pin 22 is in electrical contact with the positive section 21 of the socket 23 and the negative section 15 of pin 22 is in electrical contact with the negative section 19 of the socket 23. 
     FIG. 4 shows an alternate embodiment where three electrodes are used. A central positive electrode 31 provides the proper end connection to use in standard electrical devices. Outboard positive electrode pin 32 and shorter negative pin 33 are provided. Each of these electrodes is disposed along a line so that the peripheral pins are located 180° apart. Three sockets 34, 35, and 36 are provided. Central socket 34 is nonconducting. Negative socket 35 and positive socket 36 are disposed along a line so that the peripheral sockets are located 180° apart. Part of positive socket 36 is nonconducting and shown cross-hatched. A negative surface 37 provides the proper end connection to use in standard electrical devices. 
     FIG. 5 shows how series and parallel connections are achieved in this embodiment of the invention. For a series connection, depicted on the side view in FIG. 5b, the positive outboard electrode 32 is inserted into the negative socket 35 and the negative outboard electrode 33 is inserted in the positive socket 36. However, the negative outboard electrode 33 is not in electrical contact since it is adapted to insert solely into the neutral (i.e., insulated) part of the socket (i.e., the negative electrode is not long enough to establish electrical contact with the positive part of the socket). 
     For a parallel connection, depicted in the side view in FIG. 5a, the negative electrode 33 is inserted into the negative socket 35 and the positive electrode pin 32 has sufficient length to permit it to establish electrical contact with the positive part of the positive socket 36. 
     Various modifications of the cell design of FIG. 4 can be usefully employed, and are applicable to many of the alternate cell designs described herein. For example, the peripheral sockets and peripheral pins of FIG. 4 can be interchanged, so that the top of the battery contains the original central positive pin and two female sockets (one positive and the other negative) and the bottom of the cell contains the original central socket and two peripheral pins (one positive and the other negative). Similarly, the pins and sockets can be conveniently configured (for example, using springs in the sockets) so as to minimize contact electrical resistance via the employment of lateral mechanical forces. Additionally, the displacement of a spring-activated switch can be employed in socket 36, which will make electrical contact to the positive electrode for the long pin (pin 32), but not for the short pin (pin 33). 
     In a third embodiment of the invention, shown in FIG. 6, plate shaped prong connectors are used rather than pins. Top and bottom views of such a cell are depicted by FIGS. 6a through 6d. A central positive electrode 31 provides the standard end connection. When cells are placed end-to-end, this electrode fits into a neutral socket 34. A negative surface 37 surrounds this neutral socket 34 to provide the standard negative end. A positive prong 39 is provided on one side and a half-width negative prong 40 is provided on the opposite side. On the other end of the battery, a full width negative slot 41 is provided on one side and a slot that is less than half positive 42, and neutral 43 for the remainder, is provided on the other side. 
     FIGS. 6a and 6b illustrate the orientation of the prongs relative to the slots for parallel electrical connection. Positive electrode prong 39 inserts into slot 42 and 43 and is in electrical contact with positive electrode 42. Positive electrode pin 31 is inserted into neutral socket 34 and makes no electrical connection. Negative electrode prong 40 inserts into negative electrode slot 41 and is in electrical contact. The cells are thereby electrically connected in parallel. 
     FIGS. 6c and 6d illustrate the orientation of the prongs relative to the slots for series connection. Positive electrode prong 39 inserts into and is in electrical contact with negative electrode slot 41. Positive electrode pin 31 is inserted into neutral socket 34 and makes no electrical connection. Negative electrode prong 40 inserts into slot 42 and 43 and is disposed within the neutral portion 43 of said slot and makes no electrical connection. The cells are thereby electrically connected in series. 
     In a fourth embodiment of the invention, shown in FIG. 7, an alternate configuration of plate type prong connectors are depicted. Top and bottom views of such a cell are depicted by FIGS. 7a through 7d. A central positive electrode 31 provides the standard end connection. When the cells are placed end-to-end, this electrode fits into a neutral socket 34 and thereby makes no electrical connection. A negative surface 37 surrounds said neutral socket 34 to provide the standard negative end. A positive peripheral prong electrode 39 is provided on one side of central electrode 31 and a negative peripheral prong electrode 40 is provided 90° from positive prong electrode 39. The opposite end of the cell contains peripheral positive electrode slot 44, peripheral neutral slot 45 located 180° from positive electrode slot 44, and peripheral negative electrode slot 41 located 90° from positive electrode slot 44. 
     FIGS. 7a and 7b illustrate the orientation of the prongs relative to the slots for parallel electrical connection. Positive electrode prong 39 inserts into positive electrode slot 44 and negative electrode prong 40 inserts into negative electrode slot 41. The cells are thereby electrically connected in parallel. 
     FIGS. 7c and 7d illustrate the orientation of the prongs relative to the slots for series electrical connection. Positive electrode prong 39 inserts into negative electrode slot 41 and negative electrode prong 40 inserts into neutral slot 45. The cells are thereby electrically connected in series. 
     There are applications where series connection of higher voltage cells must be prevented. In such applications series connection could result in a potential damaging or hazardous situation because of excessive voltage, and the cells must be connected in parallel. 
     A parallel-connect only cell can be accomplished with minor variations of the series/parallel cells. Further, a parallel-connect only cell can be accomplished with a removable device added to the series/parallel cells. Thus, dual capability can be retained while accidental series connection is prevented. Also, there may be applications where the series capability is preferred. For such applications, a similar device can be added that would prevent accidental connection in parallel. 
     An optional pin and socket can be incorporated into the series/parallel configurations shown in FIG. 2. This pin and socket device is illustrated in FIG. 8. A pin 24 (which may be removable) is incorporated into one end of the cell and a mating socket 25 is included in the other end. The pin and socket force the cells to be oriented in only one way relative to each other. Thus, the cells can be parallel-connect only or series-connect only. If the pin is removed from the end, the cells can be connected in either series or parallel. This same device can be incorporated in any of the first four embodiments described herein and illustrated in FIGS. 1 through 7. 
     Further, if parallel-connect only cells that have no capability of series connection are desired, the multi-electrode pin and socket shown in FIGS. 1 through 3 can be made in a shape that permits connection only in one manner. 
     In the second embodiment depicted in FIG. 4, a partial depth plug can be inserted into the positive electrode portion of socket 36. Such a plug would prevent the cell from being electrically connected in parallel. In the third embodiment depicted in FIG. 6, a half-slot width plate can be inserted into either slot 41 or slot 42 to prevent parallel or series electrical connection, respectively. In the fourth embodiment depicted in FIG. 7, a plate can be inserted into either slot 45 or slot 44 to prevent series or parallel connection, respectively. 
     In a fifth embodiment of the invention, shown in FIG. 9, a parallel-connect only cell is shown. A central positive electrode pin 31 provides the proper end connection to use in standard electrical devices. This pin is surrounded by an annular negative electrode surface 47 that does not project as far from the end of the cell and which is separated from pin 31 by a nonconducting spacer 48. Positive electrode socket 46 and a negative electrode surface 37 are provided on the opposite end of said cell. Negative electrode surface 37 surrounds socket 46 and provides the standard negative end. Non-conducting portions of positive electrode socket 46 are shown cross-hatched. When the cells are stacked in series, positive electrode pin 31 is in contact with positive electrode socket 46 and negative electrode surface 47 is in contact with negative electrode surface 37. Thus, the cells are electrically connected in parallel. 
     In a sixth embodiment of the invention, shown in FIG. 10, yet another parallel-connect cell is shown. A central dual electrode pin 51 is provided on one end, wherein part of said pin 51 is a positive electrode 49 and part of said pin 51 is negative electrode 54. The two electrodes are electrically separated by a nonconductor 52. Positive electrode 49 provides the proper end connection to use in standard electrical devices. A negative electrode surface 37 and a dual electrode socket 50 is provided on the other end. The negative electrode surface 37 surrounds the socket 50 and provides the standard negative end. Part of the socket 50 is positive electrode 53 and part of the socket 50 is negative electrode 55. The two electrodes are electrically separated by a nonconductor 56. When the cells are stacked in series, positive electrode part 49 of the pin 51 is in contact with positive electrode portion 53 of the socket 50 and negative electrode part 54 of the pin 51 is in contact with negative electrode portion 55 of the socket 50. Thus, the cells are electrically connected in parallel. 
     The end of the cell or stack of cells of the type shown in FIGS. 9 and 10 are positive pin 31 (FIG. 9) or positive section 49 of pin 51 (FIG. 10) and negative surface 37. Thus, the battery ends are suited for conventional applications without modification to the electronic devices.