Abstract:
A receptacle in the body of a missile includes a plurality of electrical contacts connected to one or more electrically powered devices within the missile and configured to connect to an electrical power source. The receptacle receives a removable and reusable battery pack including connectors contacting the plurality of electrical contacts when the battery pack is mounted within the receptacle and one or more non-chemical, squibless batteries, preferably comprised of high power density primary cell lithium metal oxide cells. An interface circuit coupled to the squibless batteries initiates, terminates, and re-initiates delivery of electrical power from the squibless batteries to the plurality of electrical contacts based on a control input. Transportation, storage, and use risks associated with squibs in chemical batteries are avoided. During development testing, battery power may be shut down and restarted without the battery first becoming fully depleted and replaced shortening overall testing time and reducing expense.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure is directed in general to reusable flight batteries for airborne missiles or vehicles and, more particularly, to use of such batteries within weapons during testing and fielding. 
       BACKGROUND OF THE DISCLOSURE 
       [0002]    Small tactical weapons dropped or fired from helicopters or fixed-wing aircraft may use rockets for propulsion, but still require electrical power for navigation (rudder and elevator) and other internal control systems, target tracking systems, wireless communications, and global positioning system (GPS) data acquisition. Similarly UAVs may employ a liquid fuel for the propulsion system but still require electrical power for other systems. Such aircraft typically employ a flight battery for electrical power. Cost-effective testing of such aircraft during development requires that the flight battery be reusable. 
       SUMMARY OF THE DISCLOSURE 
       [0003]    A receptacle in the body of a missile includes a plurality of electrical contacts connected to one or more electrically powered devices within the missile and configured to connect to an electrical power source. The receptacle receives a removable and reusable battery pack including connectors contacting the plurality of electrical contacts when the battery pack is mounted within the receptacle and one or more non-chemical, squibless batteries, preferably comprised of high power density primary cell lithium metal oxide cells. An interface circuit coupled to the squibless batteries initiates, terminates, and re-initiates delivery of electrical power from the squibless batteries to the plurality of electrical contacts based on a control input. Transportation, storage, and use risks associated with squibs in chemical batteries are avoided. During development testing, battery power may be shut down and restarted without the battery becoming fully depleted and replaced shortening overall testing time and reducing expense. 
         [0004]    Although specific advantages have been enumerated above, various embodiments may include some, none, or all of the enumerated advantages. Additionally, other technical advantages may become readily apparent to one of ordinary skill in the art after review of the following figures and description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
           [0006]      FIG. 1  illustrates an aerial system including a reusable, resettable squibless battery in accordance with embodiments of the present disclosure; 
           [0007]      FIGS. 1A and 1B  each depict in greater detail selected portions of the structure of  FIG. 1  in accordance with embodiments of the present disclosure; and 
           [0008]      FIG. 2  is a circuit diagram for an instance of interface circuitry within an aerial system including a reusable, resettable squibless battery in accordance with embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    It should be understood at the outset that, although exemplary embodiments are illustrated in the figures and described below, the principles of the present disclosure may be implemented using any number of techniques, whether currently known or not. The present disclosure should in no way be limited to the exemplary implementations and techniques illustrated in the drawings and described below. Additionally, unless otherwise specifically noted, articles depicted in the drawings are not necessarily drawn to scale. 
         [0010]    Many development programs for airborne missiles or jet-powered vehicles require testing with a whole system operating without external power to understand and characterize how the critical components work as a system. During either of integration and testing of a new product or demonstration and testing of upgrades to an existing product, at some point performance under actual use conditions must be determined. Flight batteries for airborne missiles are often powered by a chemical reaction that is triggered by firing of a squib (small explosive charge), and generally must be allowed to completely exhaust chemical reactants before the battery can be either replaced or refurbished. Squibbed batteries are typically a long lead-time product that cannot be quickly refurbished. 
         [0011]    Squibbed batteries are also difficult to acquire for all capacities needed for a range of development programs. For example, squibbed batteries do not generally output variable voltage levels to accommodate all of the different voltage levels required by circuits inside the respective control (e.g., guidance, communications, navigation) packages of a range of systems. One system might require a 20 volt (V) output while another may require no more than 8 V, such that different battery designs or models are required for the two different systems. Still further, if a problem arises when on-board batteries must be squibbed for test and integration, there is no way to shut down the power and keep electronics from becoming overheated or stressed, possibly destroying the unit used for testing. Currently, with the use of regular flight batteries having built-in squibs, the battery fires and must be allowed to run out. 
         [0012]      FIG. 1  illustrates an aerial system including a reusable, resettable squibless battery in accordance with embodiments of the present disclosure. An aerial system  100 , illustrated as a missile in the embodiment of  FIG. 1 , includes a body  101  forming a housing containing portions of the aerial system including a propulsion subsystem, mechanical or electromechanical controls, and the like. A portion of the body  101  is shown as cutaway in  FIG. 1  to illustrate, in block diagram form, components within the body  101  relating to the reusable, resettable squibless battery of the present disclosure. Mounted within the body  101  is a battery pack  102  formed by a set of squibless batteries  103  and an interface circuit  104 . The battery pack  102  shown may be one of a plurality of battery packs mounted within the body  101 . Each battery pack  102  is accessible from an exterior of the body  101  through, for example, a removable access panel or the like. Each battery pack  102 , or at least the set of squibless batteries  103 , is contained within a discrete physical housing with appropriate electrical connectors and is therefore itself removable and replaceable, allowing the battery pack  102  or the set of squibless batteries  103  to be physically removed from the interior of the body  101  and replaced with a comparable battery pack  102  or set of squibless batteries  103 . Thus, during development, the battery pack  102  or set of squibless batteries  103  may be readily removed and replaced to facilitate testing or repeated testing of various functional elements within aerial system  100 , reducing the time required for the testing or repeated testing. 
         [0013]    The battery pack(s)  102  supply power through the interface circuitry  104  to devices and systems  105  within the body  101  requiring electrical power. To facilitate both reuse and replacement of the battery pack(s)  102 , a control  106  is included within the interface circuitry  104  for shutting down the battery power to the on-board devices/systems  105 . The control  106  might be a physical control such as a physical switch accessible from the exterior of the body  101 , but is preferably an electronic control that may be actuated either by an on-board computer within the aerial system  100  or by an external (e.g., wireless) control system communicating via antenna  107 . This control  106  allows a reset signal to be sent by the on-board computer or external control to shut down the battery power to the devices/systems  105 , allowing for reset or restoration and retesting of the devices/systems  105  until the battery pack  102  ultimately runs out of energy. This can further shorten the duration of testing and repeated testing typically required in missile development programs, beyond the time reduction achieved using a removable and replaceable battery pack as described above. 
         [0014]      FIG. 1A  depicts in greater detail selected portions of the missile  100  illustrated of  FIG. 1  in accordance with one embodiment of the present disclosure. The housing  101  contains a battery pack receptacle  110  within which the replaceable battery pack  102  may be inserted. A plurality of electrical contacts  111  within the receptacle  110  connect to the devices/systems  105  and are configured to connect to an electrical power source—the battery pack  102  in this embodiment. The battery pack  102  is supported within the receptacle  110  and removable from the receptacle  110 . In addition to the set of squibless batteries  103  and the interface circuitry  104 , the battery pack  102  also includes connectors  112  contacting the plurality of electrical contacts  111  within the receptacle  110  when the battery pack  102  is mounted within the receptacle  110 . Electrical power from squibless batteries within the battery pack  102  is transmitted through the connectors  112  and electrical contacts  111  to the electrically-powered devices/systems  105 . 
         [0015]      FIG. 1B  depicts in greater detail selected portions of the missile  100  illustrated of  FIG. 1  in accordance with an alternative embodiment of the present disclosure. In this embodiment, the housing  101  contains a battery pack receptacle  120  within which a replaceable battery pack containing the set of squibless batteries  103  (but not instances of the interface circuit  104 ) may be inserted. In this embodiment, the interface circuit  104  remains within the housing  101 . A comparable plurality of electrical contacts  121  within the receptacle  120  connect to the interface circuit  104  (which is in turn electrically connected to the devices/systems  105 ). The set of squibless batteries  103  is supported within the receptacle  120  and removable from the receptacle  120 . The housing for the set of squibless batteries  103  includes connectors  122  contacting the plurality of electrical contacts  121  within the receptacle  120  when the set of squibless batteries  103  is mounted within the receptacle  120 . 
         [0016]      FIG. 2  is a circuit diagram for an instance of interface circuitry within an aerial system including a reusable, resettable squibless battery in accordance with embodiments of the present disclosure. Circuit  200  is one instance of a portion of the interface circuitry  104 , and may be one of multiple instances of that circuit within the interface circuitry  104 , each connected to a plurality of batteries as described below and all connected to generate the power required for operation of the devices/systems  105  within the aerial system  100 . Battery set BT 1  depicted in  FIG. 2  is a set of series-connected primary cell lithium metal oxide cells (e.g., commercially available size AA batteries) that form the primary (GEU) battery. Such batteries were not previously considered for use in aerial vehicles in lieu of chemical batteries because there existed no expectation that sufficient power output could be achieved with an acceptable weight or shelf life. Battery set BT 2  is likewise a set of series-connected lithium metal oxide cells that form the secondary battery. Battery sets BT 1  and BT 2  are each connected at a negative terminal for the series to a chassis ground. 
         [0017]    Four inputs control operation of the circuit  200 : BATT_SQ_EN_H, BATT_SQ_PULSE_H, DC 2 , and BATTERY_LATCH/RESET. The input BATT_SQ_EN_H is connected to the logic input for a first metal oxide semiconductor field effect transistor (MOSFET) driver within a dual-driver circuit U 1 . The positive output for that first driver within the dual-driver circuit U 1  is connected to the gate terminal of an n-channel field effect transistor (N FET) Q 2 , while the negative output for the first driver within the dual-driver circuit U 1  is connected to a first source or drain terminal of the transistor Q 2 . The input BATT_SQ_PULSE_H is connected to the logic input for a second MOSFET driver within the dual-driver circuit U 1 . The positive output for that second driver within the dual-driver circuit U 1  is connected to the gate terminal of an N FET transistor Q 1 , while the negative output for the second driver within the dual-driver circuit U 1  is connected to both a second source or drain terminal of the transistor Q 2  and a first source or drain terminal of the transistor Q 1 . The clock and ground inputs to the dual-driver circuit U 1  are both connected to a digital ground. 
         [0018]    The input DC 2  of circuit  200  is connected to a second source or drain terminal of the transistor Q 1 . The second source or drain terminal of the transistor Q 2  is further connected to both the anode of a diode D 1  and to one end of a voltage divider formed by series-connected resistors R 1  and R 2 , where the other end of the voltage divider is connected to the chassis ground. Each of resistors R 1  and R 2  may be, for example, a 1 kilo-Ohm (kΩ) resistor. The cathode of diode D 1  is connected to an output EXT_BAT_FIRE for the circuit  200 . 
         [0019]    The input BATTERY_LATCH/RESET of circuit  200  is connected to the cathode of a diode D 4 . The anode of diode D 4  is connected to the anode of a diode D 2  and the cathode of a zener diode D 3 , which may be a 5 volt (V) zener diode. The anode of zener diode D 3  is connected to the chassis ground. Both logic inputs of a second dual-driver circuit U 2  are connected to both the cathode of diode D 2  and the connection point between resistors R 1  and R 2  in the voltage divider. Also connected to the anode of diode D 2  and the cathode of a zener diode D 3  is one terminal (a first terminal) of a resistor R 3  (e.g., a 2.2 KΩ resistor), with the other terminal (the second terminal) of resistor R 3  connected to a primary battery power output GEU_BATT_PWR for circuit  200 . The positive output for one of the two MOSFET drivers in dual-driver circuit U 2  is connected to the gate of an N FET transistor Q 4 , while the negative output for that MOSFET driver in dual-driver circuit U 2  is connected to circuit output GEU_BATT_PWR and the second terminal of resistor R 3 . One source or drain terminal for transistor Q 4  is also connected to the circuit output GEU_BATT_PWR and the second terminal of resistor R 3 . The positive output for the other of the two MOSFET drivers in dual-driver circuit U 2  is connected to the gate of an N FET transistor Q 3 , while the negative output for that other MOSFET driver in dual-driver circuit U 2  is also connected to both the circuit output GEU_BATT_PWR and the second terminal of resistor R 3 , as well as to one source or drain terminal of transistor Q 3 . The other source or drain terminal of transistor Q 3  and the other source or drain terminal of transistor Q 4  are both connected to the positive terminal of the battery set BT 1 . 
         [0020]    The anode of diode D 4  is also connected to both logic inputs of a third dual-driver circuit U 3 . The positive output for one of the two MOSFET drivers in dual-driver circuit U 3  is connected to the gate of an N FET transistor Q 6 , while the negative output for that MOSFET driver in dual-driver circuit U 3  is connected to both a circuit output SEC_BAT_VLT and one source or drain terminal for transistor Q 6 . The positive output for the other of the two MOSFET drivers in dual-driver circuit U 3  is connected to the gate of an N FET transistor Q 5 , while the negative output for that other MOSFET driver in dual-driver circuit U 3  is also connected to both the circuit output SEC_BAT_VLT, as well as to one source or drain terminal of transistor Q 5 . The other source or drain terminal of transistor Q 5  and the other source or drain terminal of transistor Q 6  are both connected to the positive terminal of the battery set BT 2 . The clock and ground inputs of both dual-driver circuit U 2  and dual-driver circuit U 3  are connected to the chassis ground. 
         [0021]    In operation, the signal received at circuit input DC 2  for circuit  200  controls the voltage output between circuit output GEU_BATT_PWR and circuit output SEC _BAT_VLT to the on-board devices/systems  105 , allowing activation of one of (at least) two voltage values. For example, the battery set BT 2  may be switched into or out of the power delivery path to alter the voltage output between circuit output GEU_BATT_PWR and circuit output SEC _BAT_VLT. Changes to resistors R 1 , R 2  and R 3  may activate either or both of the two selectable voltage values, and routine modifications to the circuit  200  would allow any one of three, four or more selectable voltage values to be output. The input BATTERY_LATCH/RESET of circuit  200  allows the battery to shut down the battery power to the on-board devices/systems  105 . The input BATTERY_LATCH/RESET is activated with the delivery of battery power from the battery pack when the battery activates (e.g., digital high), and deactivates the delivery of battery power from the battery pack when the signal is driven to ground (e.g., digital low) on that input. When the battery pack has been activated and deactivated at least once without being depleted of power, the battery pack can be reactivated in the same manner as the original activation until the battery pack is depleted. 
         [0022]    The system described facilitates testing of small tactical munitions that are designed to be dropped from an aircraft. The battery design uses commercially available, military qualified, high power density batteries with control circuitry that activates and deactivates (and reactivates) the battery power delivery. MOSFET drivers and MOSFETs are employed with a collapsing hold circuit to turn on and keep on the battery power delivery when powered up, while a feature of the collapsing hold grounds out the triggering signal to, in turn, shut off power delivery from the battery pack. If not shut off, the battery pack will operate until completely depleted. The battery pack can provide many different voltage levels, depending on application, and can be assembled to fit custom form factors. 
         [0023]    High power-density primary cell lithium metal oxide cells batteries capable of providing 5 amperes (A) steady state with 15 A surge current at 4 volts (V) per cell with commercially available size AA cells are preferably employed. Advantages of these batteries include ready availability from many vendors and ease of replacement. There are no squib concerns with such batteries, making storage less problematic. The battery pack is capable of being turned off after initiated, which cannot be done with current squibbed batteries used in most weapons. The inputs are digitally controlled, and thus do not require a high current to initiate the battery pack. 
         [0024]    The reusable battery pack described provides successful electronic control of battery operation in small tactical weapons and other airborne systems. To handle cold environments, provisions may be included to allow control of heaters inside the battery pack, enabling use of the battery pack in the absence of (sufficient) self-heating or until self-heating alone becomes sufficient. 
         [0025]    The reusable battery pack described allows for easy ground testing, cost savings over the lifetime of testing a new design, the ability to reduce component cost for the power control card within a new design, and the ability to exploit multiple voltage taps at different levels for electronics operation. End-to-end testing, including a simulated launch, is possible without the need to disassemble an all up round before flight. 
         [0026]    Modifications, additions, or omissions may be made to the systems, apparatuses, and methods described herein without departing from the scope of the disclosure. For example, the components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses disclosed herein may be performed by more, fewer, or other components and the methods described may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order. As used in this document, “each” refers to each member of a set or each member of a subset of a set. 
         [0027]    The description in the present application should not be read as implying that any particular element, step, or function is an essential or critical element which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke 35 U.S.C. §112(f) with respect to any of the appended claims or claim elements unless the exact words “means for” or “step for” are explicitly used in the particular claim, followed by a participle phrase identifying a function. Use of terms such as (but not limited to) “mechanism,” “module,” “device,” “unit,” “component,” “element,” “member,” “apparatus,” “machine,” “system,” “processor,” or “controller” within a claim is understood and intended to refer to structures known to those skilled in the relevant art, as further modified or enhanced by the features of the claims themselves, and is not intended to invoke 35 U.S.C. §112(f).