CHEMICAL AND ELECTRICAL ENERGY COMBINED EXPLOSIVE ARRANGEMENT

Description

Scope of the invention

[0001] The technical field of the invention is that of explosive assemblies combining chemical and electrical energies. State of the art

[0002] Prior art, in both military and civilian applications, describes power generators that couple a combustible or explosive charge with electromagnetic energy devices. In the military field, devices for initiating explosive charges by electromagnetic effect are known. US patent 8387534 describes an explosive charge containing carbon nanotubes (0.1 to 100 nm). Rapid heating of the nanotubes by microwave radiation induces a shock wave that initiates detonation of the explosive charge. The microwave radiation is produced either by a microwave generator coupled with waveguides or by a flux compression generator incorporating an explosive charge.

[0003] In the field of reactive armor, it is known to use explosive plates and / or electromagnetic devices to deflect / dislodge the metallic jet of an armor-piercing munition. The most common type of reactive armor is explosive reactive armor. For example, French patent application FR-A-2,670,574 describes a purely electromagnetic shield. The shield consists of capacitors connected to conductive plates. When the explosive projectile penetrates the shield, the plates are short-circuited via the projectile's body. The resulting current exerts an electromagnetic force (Lorentz force) on the projectile, causing it to deflect from its trajectory. US patent application 2004 / 0118273 describes a multilayer shield consisting of two shielding plates separated by a piezoelectric shielding plate.This intermediate plate generates an electric and / or magnetic field through mechanical stress when impacted by a projectile. Patent application WO 2006 / 085989 describes a hybrid explosive and electromagnetic reactive shield for disrupting a shaped charge jet. The reactive shield comprises a conventionally functioning explosive layer of the reactive explosive shield type, but which also mechanically activates a piezoelectric material to generate an electromagnetic field.

[0004] In the field of electromagnetic weapons, munitions combining an explosive charge with an electromagnetic wave generator are well-known. The operating principle of flux compression electromagnetic weapons has been described since the 1950s. These directed-effect weapons consist of a high-power electromagnetic generator that operates by compressing a magnetic flux using an explosive charge. The electromagnetic effect of the munition is produced by combining an explosive charge with an electrical circuit. The operation of the explosive charge deforms a solenoid carrying a current until the solenoid's windings short-circuit. The deformation of the solenoid gradually reduces its inductance, much like a rheostat. The current flowing through the solenoid increases, and the electromagnetic field generated by the solenoid is then amplified almost instantaneously.French patent application FR2 783 316 describes a weapon of this type equipped with a transmitting antenna. Upon initial activation, a battery located at the front of the munition (on the antenna side) charges a capacitor, which then supplies current to the solenoid before the explosive charge detonates. The cylindrical explosive charge is inserted into a copper tube positioned within the solenoid's channel. In this type of weapon, the explosive's function is therefore to disrupt an electrical circuit powered by a current generator consisting of a battery and a capacitor.

[0005] In civilian applications, electrochemical accumulators exist for initiating detonators, comprising an explosive electrolyte. US patent application 2014 / 0230679 describes an electrochemical accumulator in which the electrolyte is an explosive compound or a compound derived from an explosive. This device is intended for use as an electrical generator for initiating mine blasts. The explosive compound is an ammonium nitrate-based emulsion that may contain additives to increase its electrical conductivity. There are also so-called "thermal" batteries activated by a combustible pyrotechnic charge. US patent application 2018 / 0099912 describes the use of combustible pyrotechnic elements for the activation, by heating, of an electrolyte from an inert solid state to an ionic liquid state in so-called "thermal" batteries.Miniaturized batteries containing combustible materials that serve as anode and cathode are also known. US patent 6042963 describes a pyrotechnic current generator used, for example, as a fire detector. The generator comprises an anode made of an energetic material with an excess of reducing agent and a cathode made of an energetic material with an excess of oxidizing agent. The cathode and anode are separated by a layer of fluorinated alkaline earth material or lithium fluoride. US patent application 2015 / 184486 describes a spherical device for generating explosive fragments for well fracturing. This device consists of an assembly of a ceramic sphere and an explosive charge. A space is reserved in the center of the sphere to contain an explosive charge, a detonator, and a battery. The battery's role is to generate the initiation current for the detonator of the explosive charge.The explosive charge shatters the ceramic sphere. In this type of device, the battery plays a secondary role upstream of the explosive's detonation, and its energy density is limited to that required to initiate the detonator.

[0006] Furthermore, in the field of electrochemical batteries, the stored electrical energy (E) is constantly increasing. Conventional batteries, for example Li-ion batteries, can store approximately 280 Wh / kg or 0.72 MJ / kg, or even 500 Wh / kg or 1.8 MJ / kg. New generations of Li-S batteries are likely to store more than 500 Wh / kg or 1.8 MJ / kg, or even 1400 Wh / kg or 5 MJ / kg in the relatively short term (ref: INERIS Report "High Energy Density Li-S Battery: Differences with Li-ion Technology, Risk Assessment and Safety," No. DRA-19-180147-00590A of 07 / 02 / 2019). It should be noted that theoretical electrical storage values ​​of more than 10,000 Wh / kg or 36 MJ / kg are announced for Li-air batteries under development.The electrical energy stored in current batteries is therefore of the same order of magnitude (or even, in the near future, an order of magnitude greater) as the energy released by the detonation of the reference explosive, trinitrotoluene (TNT), approximately 4.2 MJ / kg. The safety of battery use is the subject of numerous studies, particularly for applications in transportation. Li-ion batteries with liquid organic electrolytes are susceptible, when subjected to malfunctioning heating (caused by a short circuit or fire), to thermal runaway followed by explosion. The thermal energy released is significant, approximately six times the amount of electrical energy stored in the battery, according to tests conducted in the presence of air and a combustion gas ignition source (ref: "Investigation on the fire-induced hazards of Li-ion battery cells by fire calorimetry," Perrine Ribière et al.)., Energy and Environmental Sciences, 2012,5,5271). The reaction energy is almost constant and the power increases with the battery charge.

[0007] The thermal reaction energy values ​​for new generations of improved safety batteries, for example with non-flammable inorganic electrolyte, are considerably reduced compared to batteries with organic electrolyte.

[0008] In the field of electrostatic storage devices, such as supercapacitors, stored energy densities are lower than those stored by electrochemical batteries, ranging from approximately 1 Wh / kg to 5 Wh / kg. Ongoing research using nanotechnology suggests the possibility of storing up to 100 Wh / kg. Summary of the invention

[0009] Advances in energy storage using electrical accumulators have led the applicant to design an explosive assembly combining chemical and electrical energy. The invention relates to an assembly for military munitions, composed of an explosive charge equipped with its initiation means and at least one electrochemical and / or electrostatic (supercapacitor) electrical accumulator, preferably several electrical accumulators constituting a battery and / or a series of supercapacitors. The assembly is configured such that the detonation of the explosive charge results in the near-instantaneous destruction of at least one electrical accumulator. The destruction of at least one electrical accumulator is thus comparable to a near-instantaneous, massive burst of perforation and / or short circuit.The total energy released by the assembly upon detonation of the explosive charge is the sum of the energy released by the explosive charge itself and the energy released by the destruction of at least one electrical accumulator. The energy released by the at least one electrical accumulator upon its destruction is primarily electrical in origin and secondarily chemical (through reactions between the compounds of the at least one electrical accumulator and with the environment). It is therefore understood that in the assembly according to the invention, the role of the electrical accumulator is not to supply current to an electrical circuit but to release electrochemical energy upon its destruction.

[0010] The electrical energy stored by at least one battery depends on its (or their) state(s) of charge. Therefore, the invention has the advantage of allowing the released energy to be modulated by adjusting the state of charge of at least one battery from 0% to 100%. Thus, each battery can have a charge of, for example, 0%, 30%, 50%, 70%, 90%, or 100%. When the assembly contains several batteries, the state of charge of each battery is either identical or variable, depending on the desired energy level. The assembly of the invention also has the advantage of being able to be stored with 0% charge of at least one battery, thereby limiting the risk in the event of accidental activation.

[0011] In one embodiment, several assemblies according to the invention can be used with the aim of increasing the energy released and / or having greater latitude in adjusting the energy released. Brief description of the figures

[0012] There figure 1 represents a battery coupled with an external explosive charge consisting of a cylindrical solid explosive block with a central channel. figure 2 represents a cross-sectional view of the battery according to the figure 1 . There figure 3 represents a battery coupled with an internal explosive charge consisting of plastic explosive blocks inserted between the accumulators. figure 4 represents a side view of the battery according to the figure 3 . There figure 5 represents a battery with a block of plastic explosive on each of its lateral faces. figure 6 represents a cross-sectional view of the battery according to the figure 5 . Description of the invention

[0013] The invention relates to an explosive assembly for military munition, composed of an explosive charge equipped with its initiation means (detonator and initiation relay) and at least one electrical accumulator of electrochemical and / or electrostatic type (of the supercapacitor type), preferably of several electrical accumulators constituting a battery and / or a series of supercapacitors.

[0014] In one embodiment, the explosive assembly for military munitions comprises an explosive charge equipped with its initiation means (detonator and initiation relay) and at least one electrochemical accumulator, preferably several electrochemical accumulators forming a battery. The explosive charge, when detonated, causes the instantaneous destruction of at least one electrochemical accumulator. This explosive destruction releases almost instantaneously the electrical energy stored by the electrochemical accumulator(s). It also causes the release of thermal energy through the reaction of the compounds in at least one electrochemical accumulator with each other and with the environment (air, surrounding materials).

[0015] The total energy generated, according to the process of the invention, therefore combines the detonation energy Eexplo of the explosive charge with the electrical energy Eelectrical of at least one electrochemical accumulator and, secondarily, with the thermal energy Tthermal of the chemical reaction of the constituents of at least one electrochemical accumulator, as explained below. The mode of release of the electrical energy Eelectrical contained in the at least one electrochemical accumulator at the moment of its (their) destruction by the detonation wave of the explosive charge can be thermal, ionic (plasma), or electromagnetic.

[0016] If, for example, we consider an explosive charge of TNT combined with a battery of electrical energy capacity of 1000 Wh / kg (3.6 MJ / kg) of the type developed by the company Innolith, the energy balance of the reaction for 1 kg of TNT combined with 1 kg of battery in a state of maximum electrical charge is then: E 1 = E explo + E électrique = 4,2 + 3,6 = 7,8 MJ .

[0017] The calculation for a realistic case can be performed with 2 kg of TNT acting on a 20 kg battery (of the type indicated above) in a state of maximum electrical charge. The energy delivered instantaneously is then E1 = 8.4 + (3.6 x 20) = 80.4 MJ.

[0018] The thermal energy Ethermal, produced over a longer period by the chemical reaction of the components of at least one electrochemical cell, must be added to the energy E1 (detonation energy + electrical energy). This energy depends on the battery's components, particularly the nature of the electrolyte.

[0019] For standard safety tests involving malfunctioning battery heating, this thermal energy (Ethermal) is typically released over a period ranging from 50 seconds to several minutes, depending on the battery's charge level. In the case of the present invention, thermal energy production by chemical reaction occurs over much shorter periods than those of standard safety tests. Indeed, the near-instantaneous destruction of the battery cells by the detonation wave of the explosive charge leads to rapid contact between the battery components and with the surrounding air. The production time of this thermal energy by a redox-type chemical reaction remains, however, longer than the near-instantaneous release time of the detonation and electrical energies.

[0020] According to another embodiment, the explosive assembly for military ammunition consists of an explosive charge equipped with its initiation means (detonator and initiation relay) and at least one electrostatic accumulator, of the supercapacitor type, preferably several electrostatic accumulators.

[0021] According to another embodiment, the explosive assembly for military ammunition comprises an explosive charge equipped with its initiation means (detonator and initiation relay) and at least one electrostatic accumulator, for example of the supercapacitor type, and at least one electrochemical accumulator, preferably several electrostatic accumulators and several electrochemical accumulators. The considerations relating to the total energy generated under the first embodiment described above apply. mutatis mutandis to other embodiments described.

[0022] In one embodiment, which can be combined with the preceding embodiments, the explosive charge assembled with at least one electric accumulator consists of at least one plastic explosive block (e.g., type C4 or HEXOMAX®) or at least one self-adhesive plastic explosive strip (e.g., type HEXOTAPE®) or at least one plastic explosive sheet (e.g., type HEXOSHEET®). The explosive charge can also be solid, such as a compressed solid explosive block (e.g., type HEXOWAX®) or a composite explosive block with a cross-linked binder of type HMX or RDX / polyurethane binder, for example, explosive PBXN-109. Such explosive charges are marketed by Eurenco under the aforementioned brand names and the designation PBXN-109.

[0023] The electrochemical and / or electrostatic accumulator(s) is / are inserted into the explosive charge, in particular within the channel thereof; or alternatively, the explosive charge is arranged around and / or between the electrochemical and / or electrostatic accumulator(s). It will be understood that any of these embodiments can be combined with other embodiments of the invention.

[0024] In one embodiment, when the electrical accumulator(s) is / are arranged in a structure, the positioning of the explosive charge may be external and / or internal to the structure. According to one aspect of this embodiment, the structure in which the accumulator(s) is / are arranged is a strong or armored structure, in which case the explosive charge is preferably a shaped explosive charge.

[0025] The assembly of the invention for military munitions is suitable as an explosive charge for bombs, missile warheads, or torpedo warheads. The assembly of the invention therefore finds particular application in: In general, as a military warhead with improved storage safety, the charge of at least one electric accumulator being 0% in storage conditions, for example, as an explosive bomb charge, for example of type Mk82, with power modulated according to the state of charge of at least one electric accumulator, for example, as a military warhead for a submarine torpedo in order to reduce the quantity of explosive for the same explosive power.

[0026] The invention is illustrated by the following examples, given for illustrative purposes only. Example 1

[0027] With reference to Figures 1 And 2 The device comprises 50 electrochemical accumulators. (1)of the LICERION™ type (with a mass energy density of 500 Wh / kg (1.8 MJ / kg) and a volumetric energy density of 1000 Wh / L (3.6 MJ / L), unit dimensions: height = 10 cm, width = 10 cm, thickness = 1 cm, unit mass = 0.154 kg) marketed by the company Sion Power, forming a battery (2) with dimensions 10 cm x 10 cm x 50 cm and a mass of 7.7 kg. This battery is placed in the channel (3) of an explosive charge (4)consisting of a solid cylindrical explosive block with an outside diameter of 17.7 cm and a central channel with a rectangular cross-section of sides I1 = 12.5 cm and I2 = 10 cm, with a mass of 10 kg, made of PBXN-109 (with a density of approximately 1.65 g / cm³), comprising, by mass, 64% hexogen, 20% aluminum, and 16% polyurethane binder (PBHT). The PBXN-109 composition releases an equivalent detonation energy estimated at 1.2 times that of TNT, or approximately 5 MJ / kg. The combined energy E1 of the detonation and electrical energy for this device is approximately 63.9 MJ. The device is inserted into a structure (5), for example, a bomb casing or a missile warhead. Example 2

[0028] With reference to figures 3 and 4 The device comprises 50 electrochemical accumulators. [1]The batteries are joined together in a LICERION™ type (energy density of 500 Wh / kg (1.8 MJ / kg), unit dimensions: height = 10 cm, width = 10 cm, thickness = 1 cm, unit mass = 0.154 kg) marketed by Sion Power, forming a battery (2) with dimensions of 10 cm x 10 cm x 50 cm and a mass of 7.7 kg. The batteries are separated by 49 plastic explosive elements (6) of type C4 or HEXOMAX® (density approximately 1.65 g / cm³). Each explosive element has the following dimensions: height = 10 cm, width = 10 cm, thickness = 1.24 cm. The total mass of explosive is 10 kg. The C4 explosive releases a detonation energy equivalent to an estimated 1.3 times that of TNT, or approximately 5.5 MJ / kg. A hoop (7) ensures the stability of the assembly. The combined energy E1 of the detonation energy and the electrical energy for this device is approximately 68.9 MJ. Example 3

[0029] With reference to figures 5 and 6 The device comprises 50 electrochemical accumulators.(1)attached LICERION™ type batteries (energy density of 500 Wh / kg (1.8 MJ / kg), unit dimensions: height = 10 cm, width = 10 cm, thickness = 1 cm, unit mass = 0.154 kg) marketed by Sion Power, forming a battery (2) with dimensions 10 cm x 10 cm x 50 cm and a mass of 7.7 kg. The battery includes on each side a C4 type plastic explosive block (density 1.65 g / cm³) marketed by Eurenco. Two blocks (8) along the length of the battery have a unit mass of 4.27 kg and dimensions of length = 58.8 cm, width = 10 cm, and thickness = 4.4 cm. Two blocks (9) along the width of the battery have a unit mass of 0.726 kg and dimensions of length = 10 cm, width = 10 cm, and thickness = 4.4 cm. The C4 explosive releases a detonation energy equivalent to approximately 1.3 times that of TNT, or approximately 5.5 MJ / kg. The combined energy E1 of the detonation and electrical energy for this device is approximately 68.8 MJ.

Claims

1. Explosive assembly for military ammunition, composed of an explosive charge provided with its means of initiation and of several electrochemical and / or electrostatic accumulators (1) forming a battery (2) and / or a series of supercapacitors, in which the electrochemical and / or electrostatic accumulators are inserted into the explosive charge (4), or in which the explosive charge (6,8,9) is arranged around and / or between the electrochemical and / or electrostatic accumulators.

2. The explosive assembly of claim 1, comprising a plurality of electrochemical accumulators forming a battery.

3. The explosive assembly of claim 2, wherein the charge of each electrical accumulator is in the range from 0% to 100%.

4. The explosive assembly of claim 3, wherein the charge of each electrical accumulator is identical.

5. The explosive assembly of claim 3, wherein the charge of at least two electrical accumulators is different.

6. The explosive assembly of claim 1, comprising a plurality of electrostatic accumulators forming a series of supercapacitors.

7. The explosive assembly of claim 1, comprising a plurality of electrostatic accumulators and a plurality of electrochemical accumulators forming a battery and a series of supercapacitors, respectively.

8. The explosive assembly of any one of claims 1 to 7, wherein the explosive charge consists of at least one plastic explosive block, or at least one self-adhesive plastic explosive tape, or at least one plastic explosive foil, or at least one compressed solid explosive block, or at least one solid composite explosive block with a cross-linked binder.