This invention pertains to a Reserve Battery activated by shock without spin which can reliably deliver electrical power. They have a long storage life and high power capabilities which makes them useful for military applications especially for fuzes used in non spinning ammunitions as well as less spinning ammunitions. The increased shelf-life, higher energy density and faster activation makes it more attractive when compared with the batteries under this class.

Electronic fuzing systems for controlling projectile war heads are well known in the art. Hence a reliable power source with adequate power density with rapid activation is an essential requirement to the fuze electronics during flight. Fuze electronics may include controllers, timing circuitry, and various sensors. Additionally, the fuze electronics may include a safety and arming mechanism to ensure that both the arming and detonation of the projectile occur only at a desired moment.

As part of our endeavor to develop for devices requiring power source having high reliability, quick activation and long storage life, which can be retained in inventory for utilization in time of need, we have come out with a novel Battery design. Such batteries are very effective in operation in environments that may be subjected to very low sub-zero temperatures or very high terrestrial temperatures and also comply with the requirement of MIL-STD 331C and MIL- STD810G.

The Battery under our invention has been provided utilizing such high density battery cells, so that they will be available for applications where the battery may be kept in storage and held in reserve for relatively long periods of time before being called into service and be able to be activated for immediate service when desired.

The state of the art Reserve Battery under our invention can be activated by shock alone without even spin. This Battery is more appropriately used for the Mortar fuze as well as other smart ammunitions. In such application, the Battery should activate when the ammunition is fired. It comprises of a cell stack of lithium electrodes and carbon electrodes separated by a glass separator wound spirally and these cell stack arrangements aire further separated by insulators and the electrode arrangements connected to each other in series around a former; ampoule filled with thionyl chloride electrolyte and kept under tension by means of a spring fixed to former below the ampoule and an activating system consisting of an anvil fixed to former below the ampoule. The entire assembly is housed in a Battery case and closed with the Battery bottom lid. On firing, the ampoule kept under tension by the spring is broken by the anvil and makes the electrolyte to flow out of the ampoule due to setback action and enter into the electrode arrangement and the electrochemical reaction commences and electrical power can be drawn.

The shock activated Reserve Battery comprise of a plurality of lithium-carbon electrodes wrapped one over the other, with insulator, in such a way that the Lithium electrode and carbon electrode are isolated by a glass separator and these stacks are wound spirally, and further separated by an insulator film wound along with the stacks and connected to each other in series and with an ampoule filled with liquid thionyl chloride electrolyte including an activating system which breaks the said ampoule at a predetermined acceleration level, and a housing in which this said cell-stack, this said ampoule and this said activating system are placed.

Accordingly our invention pertains to a Reserve Battery activated by shock comprising a cell stack of electrodes; an ampoule containing an electrolyte; an activating system; a Battery case in which the said cell-stack, ampoule and activating system are placed; characterized wherein the cell-stack of electrodes has spiral shape comprising rectangular carbon electrode and lithium electrode separated from each other by a separator wherein these cell stack of electrodes are in turn separated by rectangular insulator films wound around the former at the lower portion of the former and wherein the fragile glass ampoule having Thionyl Chloride electrolyte, positioned at the hollow portion above the activating system of the Battery and whereas the said activating system comprising of an anvil and a spring fixed firmly at the appropriate grooves of the former at the lower part of the former at the center and capable of breaking the ampoule resting on the spring at a predetermined acceleration, wherein the former is having provision to distribute the electrolyte into the voids between the spiral electrodes, to activate the cells and generate electrical power; and capable of closing the Battery case by means of the Battery bottom lid.

Now the invention will be described in more detail with reference to the accompanying drawings bringing out the embodiments of the arrangement according to the invention in which figures and descriptions are given as under.

Fig. 1 Exploded view of Reserve Battery activated by shock Fig. 2 Sectional view of the Battery

Fig. 3 Sectional view of former having single row of slits for electrolyte flow

Fig. 4 Sectional view of former having multiple slits for electrolyte flow

Fig. 5 Isometric view of Battery bottom lid

Fig. 6 Isometric view of the electrode stack arrangement.

Fig. 7 Isometric view of details of single set of electrodes and separator

Fig. 8 Typical activation profile of Reserve Battery activated by shock

Wherein

1) Battery case, 2) Flexible rubber sleeve, 3) Glass Ampoule, 4) Spring, 5) Anvil, 6) Former, 7) Cell stack, 8) Bottom cup, 9) Battery bottom lid, 10) Positive terminal, 11) Fuze locater pin 12) Glass to metal seal, 13) Former housing, 14) Spring groove, 15) Slot for the anvil, 16) Slot in the former for fixing with bottom cup, 17) Electrolyte outlet slits, 18) Annular disc of the former, 19) Lithium electrode, 20) Carbon electrode, 21) Separator, 22) Insulator

The major parts of the Reserve Battery under our invention are, a characteristic and novel cell stack of electrodes; insulators between the electrode stacks; a glass ampoule containing electrolyte; an activating system comprising of anvil and spring; a former to hold on cell stack, ampoule and activating system; a bottom cup to insulate the cell stack arrangement from the Battery case; and finally a Battery case with bottom lid in which the said former holding cell-stack, ampoule, activating system, and the bottom cup are placed.

Cell stack arrangement: The cell stack arrangement (7) in the said invention is comprising of lithium electrode (19) pressed on a metal wire mesh selected from nickel, stainless steel, silver, or any suitable metal which functions as cathode, and carbon powder pasted on a metal wire mesh selected from nickel, stainless steel, silver, or any suitable metal forms the carbon electrode (20) and functions as anode. The lithium electrode is made by pressing a lithium metal sheet of predefined thickness on a metal wire mesh selected from nickel, stainless steel, silver or any suitable metal, to which a nickel strip which functions as the lead for drawing electric power is attached preferably by resistance welding before the pressing the Lithium metal sheet. Later on, this nickel strip is soldered to the Battery case (1), once the former with electrode assembly is inserted into the Battery case. The process is done in a in a dry inert atmosphere with a very low relative humidity and low temperature, as lithium is highly reactive and hydrolyzes even if exposed to atmospheric moisture and can form nitrate compounds with atmospheric air in presence of moisture. The carbon electrode (20) is made by pasting a mixture of carbon powder and a binder preferably Polytetrafluroethylene suspension on a metal wire mesh selected from nickel, stainless steel, silver or any suitable metal, to which a nickel strip is attached preferably by resistance welding. This nickel strip which functions as the positive lead is welded to the positive terminal (10) of the Battery lid (9) once the former with electrode assembly is inserted in the Battery case. The electrodes are separated by an insulating material, selected form cellulosic paper, polythene film, nylon film or glass mat, preferably a non woven glass mat insulating medium called herein after as separator (21) in the present invention. The cells are made by spiraling the rectangular lithium electrode (19), separator (21) and carbon electrode (20) placed one over the other in the respective order around the former (6), such that the lithium and carbon electrodes do not come into physical contact with each other during the spiraling process. Each of such electrode set (19,20,21) is separated by a rectangular insulator (22) sheet made from PTFE, Nylon, glass, polyethylene or any similar insulation material by placing in between the said electrode sets. Plurality of such cells (19, 20, 21, and 22) are wound spirally over the former and the electrodes are connected in series to complete the circuit. The width and the length of the insulator is more than the that of the electrode set (19, 20, 21) and wound around the former in such a way that, the insulator (22) will stand a few millimeter above the electrode set, so that the electrolyte which flashes through the slits (17) of the former, maintain a certain level above the electrode set. Thus the insulator prevents the leakage current by preventing the leakage path. Once the stack assembly is completed, the former is inserted in bottom cup (8) preferably made of PTFE to insulate the electrodes from the metallic Battery case (1).

In one of the preferred embodiments under our invention, one lead from the carbon electrode (first in the series of spiral cells) is connected to the positive terminal (10) embedded in the Battery bottom lid preferably by way of soldering. This lead together with the cell stack arrangement is insulated from the Battery case by a bottom cup (8), which is placed suitably and lid by the glass to metal seal (12) provided in the battery bottom lid. The bottom cup has a raised step which can fit snugly to the slot in the former for fixing with bottom cup (16). The positive terminal to which lead of the carbon electrode is soldered is separated from the bottom lid via a glass seal (12). One lead from the extreme lithium electrode (last in the series of spiral cells) is connected to the Battery case preferably by resistance welding. The nickel strip of lithium electrode of the first spiral cell is connected to the nickel strip of carbon electrode of the second spiral cell preferably by resistance welding. Alternatively they can be soldered. The Nickel strip of lithium electrode of the second spiral cell is connected to the Nickel strip of carbon electrode of the third spiral cell and so on. The Nickel strip of lithium electrode of the penultimate cell is connected to the Nickel strip of the carbon electrode of last cell to complete the series connection. This arrangement is effectively sealed at the area of connection by potting with a sealant mixture containing a resin and an accelerator. This arrangement is cured to ensure effective sealing.

Glass ampoule: The Glass ampoule (3) is made from glass tube, preferably of boro silicate chemistry, and will hold the electrolyte in it, as boro silicate glasses are known for having very low coefficients of thermal expansion (~3x10 06/°C at 20°C), making them resistant to thermal shock, more so than any other common glass. Such glass is less affected by thermal stress and is commonly used for the construction of reagent bottles also. The electrolyte is filled in the ampoule, in a dry inert atmosphere with a very low relative humidity and low temperature, and then the neck of the ampoule is closed suitably by tig welding or flame welding or laser welding to prevent the electrolyte to come out of the ampoule before the Battery is activated. Electrolyte used for this type of Reserve Battery is Thionyl chloride, with chlorides of Potassium, Aluminium, and Lithium as additives.

Former: The former (6) houses the activating mechanism viz. glass ampoule (3), spring (4), and anvil (5). The former has cylindrical shape with a hollow cylindrical portion on the topside for housing the glass ampoule (3) which also is cylindrical in shape. An annular disc (18) is fixed at the central portion of the former by means of ribs to facilitate free flow of electrolyte once the glass ampoule is broken and the electrolyte comes out of the interior of the former to outside through the rectangular electrolyte outlet slits (17) provided in the cylindrical portion of the former in series of rows. Each of these openings in the former act as channels for facilitating the flow of electrolyte into the void space of the electrode stack arrangement. The design of the former is done in such a way, that though it enables the free flow of the electrolyte into the stack arrangements, it will not allow the glass pieces and prevent them from entering into the cell stack (7) while the Battery is activated. Top inside portion of the former is cushioned by a flexible rubber sleeve (2) preferably made of viton rubber to protect the glass ampoule (3) from breakage due to mechanical shocks during transportation. Further, the same sleeve also protects the neck of the ampoule when the Battery is subjected to lateral shocks. The former is designed in such a way that it can hold the spring (4) firmly in the spring groove (14) provided. The spring is assembled over the anvil (5) located in the slot for anvil (15). The anvil can be a foil or solid metal block, or a shear cutter or a plurality of pins located strategically to puncture and simultaneously crush the ampoule. In a preferred embodiment under this invention, the anvil is a longitudinal shearing blade. The shock received by the anvil during the muzzle firing is imparted to the ampoule (3) containing the electrolyte which is kept under tension by means of spring. Then the ampoule apparently travels backwards during muzzle firing, thereby enabling it to be crushed, allowing the electrolyte to flow out of the ampoule and enter into the cell stack by set back effect. This design also helps to flow the electrolyte from the ampoule once it is broken, in a uniform way into the channels provided over the spiral cells, through which the electrolyte enters the voids between the spiral electrode stack, thus activating the cells to generate electrical power.

The Battery case (1) can be made of metal, preferably Nickel or SS 304, or nickel plated MS or any suitable metal/ alloy to withstand the corrosive action of electrolyte. The shape is selected from any suitable profiles like cylindrical, square, conical, or based on the customer's requirement. The case can hold one or more cells, as defined by the voltage requirements. In the preferred embodiment, the Battery case is in cylindrical shape and made of SS 304. The Battery is constructed to house multi-cell system.

The Battery bottom lid (9) is having 2 holes drilled and threaded suitably. Positive terminal (10) is located in one hole and this positive terminal is separated from the bottom lid by a glass to metal seal (12). The second hole for assembling the fuze locater pin (11), which enables the Battery to be locked into the fuze. Battery body acts as the negative terminal. The Battery lid is finally welded to the Battery case by way of laser welding or TIG welding.

On muzzle firing, the ampoule kept under tension by the spring is broken by the anvil and makes the electrolyte to flow out of the ampoule due to set back action and enter into the electrode arrangement. The separator kept between the electrodes absorbs the electrolyte due to its high porosity and the electrochemical reaction sets in and electrical power is generated.

Some of the special features of this Battery are as under:

• This Battery is designed to activate, when subjected to shocks in excess of 600 'g's with no spin induced, which is not possible in the contemporary lithium Reserve Batteries

• The former is designed in such a way that the inner wall of the former act as guide for the ampoule to directly fall on to the anvil, while holding the electrode stack on the outer wall.

• Flexibility in design is available for increasing the voltage by introducing plurality of electrode stacks.

• The Battery is designed in such a way that it will not activate when dropped from a height of up to 1.5 meters, which in fact is equal to subjecting it to a momentary shock in the order of 6000 'g', but will activate only if it is subjected to a sustained shock in excess of 600 'g'.

Some of the features according to one of the preferred embodiments under which prototype is made are given below by way of reference and is not a limitation, as possibilities exist to increase the capacity and mode of activation by suitably altering without deviating from the ambit of this invention.
General Characteristics

1. Electro chemistry: Lithium/Thionyl Chloride(Li/SOCI2)

2. Storage Life: 20 years

3. Configuration: multi cell stack as per voltage requirement

Performance Characteristics

1. Operating Voltage : >12.0 Volts

2. Current : 200 Ma

3. Capacity :>10.0mAh

4. Activation Time : <250 milli seconds

5. RunTime : >180 seconds

Dimensions

1. Diameter (nominal) :37.0 mm

2. Length (nominal) : 50.0 millimeters (w/o terminals)

3. Weight (nominal) : <100.0 grams

Physical Characteristics

1. Operating Temperature Range :-40°C to+70°C

2. Storage Temperature : -54°C to +70°C

3. Connector : 2 Pins; 1 for Power the other connector being the body, 1 acts as locating pin.

4. Activation Mechanism :Shock +Simultaneous spin

5. Case & Mounting Flange : Stainless Steel

As explained above we could come out with a novel design which is not only highly reliable in meeting the stringent specification requirements of the military but also is less expensive and is easy to manufacture. These batteries will not activate from slight shock or jerks as the artillery shell can be accidentally dropped but will fully activate when subjected to a sustained shock of 600 'g' and above. Similarly it can withstand extreme climatic conditions during storage and can activate and perform reliably even at extreme temperature conditions.

Here efforts have been made broadly to explain some of the features of the invention with detailed description thereof for better understanding. One of the embodiments under the invention in detail is given only for clarity, it is to be understood that the invention is not limited in its application to the details of construction or to the arrangements of the components set forth in the above description and illustrated in the drawings. This invention is capable of other embodiments and can be practiced and carried out in various ways. Further, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting factor.

We Claim

1. A Reserve Battery activated by shock comprising a cell stack of electrodes; an ampoule (3) containing an electrolyte, an activating system, a Battery case (1) in which the said cell-stack, ampoule and activating system are placed; characterized wherein the cell-stack of electrodes has spiral shape comprising rectangular carbon electrode (20) and lithium electrode (19) separated from each other by a separator (21) and wherein these cell stack of electrodes are in turn separated by rectangular insulator (22) films wound around the former at the lower portion of the former (6) and inserted in a bottom cup (8) made of plastic material, wherein the fragile glass ampoule (3) having Thionyl Chloride electrolyte, positioned at the hollow portion above the activating system of the Battery and whereas the said activating system comprising of an anvil (5) and a spring (4) fixed firmly at the appropriate grooves of the former (6) at the lower part of the former at the center and capable of breaking the ampoule resting on the spring, at a predetermined acceleration, wherein the former is having provision to distribute the electrolyte into the voids between the spiral electrodes to activate the cells and generate electrical power; and capable of closing the Battery case (1) by means of the Battery bottom lid (9).

2. The Reserve Battery activated by shock as claimed in claim 1, wherein the former (6) is having an annular disc (18) with ribs at the middle portion, with slits (17) on the periphery at its center above the electrode stack arrangement (19,20,21) and insulators (22) capable of distributing the electrolyte in the form of a flash over the electrode stack facilitating to enter into the voids between the spiral electrodes due to the shock resulting in the activation of the cells to generate electrical power and finally a Battery case (1) in which the said cell- stack, ampoule (3) and activating system are placed and closed by a Battery bottom lid (9).

3. The Reserve Battery activated by shock as claimed in claim 1, wherein the carbon electrode (20) is made by pasting the carbon powder mixed with a binder selected from Polytetrafluroethylene suspension, on a metal mesh selected from nickel, stainless steel, silver or any other suitable metal, to which the positive lead is provided for drawing electric power and is connected to the pin of the Battery bottom lid (9) and the lithium electrode (19) is made by pressing lithium metal sheet of predefined thickness on a metal mesh selected from nickel, stainless steel, silver or any other suitable metal to which the negative lead is provided and connected to the Battery case (1) once the former (6) with electrode assembly is inserted in the Battery case.

4. The Reserve Battery activated by shock as claimed in claim 1, wherein electrodes are capable of wrapping one over another, isolated by a non conductive separator (21) selected form cellulosic paper, polythene film, nylon film, or glass mat, preferably a non woven glass mat insulating medium and each set of electrodes (19,20,21) is separated by a rectangular insulator (22) foil made from material selected from PTFE, nylon, glass, polyethylene, viton rubber or any suitable insulator by placing it in between the said electrode stack arrangement wherein the width and the length of the insulator (22) is more than the that of the electrode set (19, 20, 21) and spirally wound around the former in such a way that the insulator (22) will stand above the electrode set so that the electrolyte which flashes through the slits (17) of the former maintains a certain level above the electrode set to prevent the leakage current by preventing the leakage path; this arrangement enables the subject Battery to function with or without spin.

5. The Reserve Battery activated by shock as claimed in claim 1, wherein the glass ampoule (3) is made from glass tube, preferably of boro silicate glass and provided with a flexible rubber sleeve (2) to function as a cushion at the top side of the former (6) to protect the nipple end of the ampoule from breakage on impact with the Battery case (1) due to mechanical shocks during transportation, and capable of holding the liquid electrolyte comprising of thionyl chloride with additives selected from chlorides of Potassium, Aluminium, and Lithium.

6. The Reserve Battery activated by shock as claimed in claim 1, wherein the carbon electrode lead terminal, together with the cell stack arrangement is insulated from the Battery bottom lid (9) and Battery case (1) by an insulating bottom cup (8) made of insulating material, preferably Polytetrafluroethylene.

7. The Reserve Battery activated by shock as claimed in claim 1, wherein anvil (5) facing upward is selected from a solid metal block, a longitudinal shear cutter and singularity or plurality of pins located strategically to puncture and simultaneously crush the ampoule.

8. The Reserve Battery activated by shock as claimed in claim 1, wherein it is capable of operating at a temperature range of -40°C to +70°C and withstanding a storage temperature range of -54°C to +70°C and meeting the requirements of MIL-STD 331C , and MIL- STD 81OG.

9. The Reserve Battery activated by shock as claimed in claim 1, wherein the said Battery is designed to activate when subjected to a set back shock in excess of 600 'g' and also withstand the drop test as per the MIL-STD 331C, and MIL- STD 810G.

10. A Reserve Battery activated by shock as claimed in claim 1 substantially herein described with reference to and illustrated in figure 1 to 8 of the accompanying drawings.