Power source

Abstract

A heat activated power source is disclosed that includes an anode element, a cathode element, and an electrolyte element, all of which are stacked in an electrically conductive shell so as to form a unitary body therein. The electrolyte is of a type that is ionically passive below a certain temperature and that is ionically active above that temperature. One of the anode and cathode elements serves the additional purpose of providing for heat amplification, and thus amplifies an otherwise too small heat energy signal so that it is enough for activating the electrolyte. The power source is particularly suitable for use in pyro-electric detonator applications, where it facilitates highly accurate delay times that are virtually independent of the delay time duration. The power source is suitable for large scale manufacturing, with maintained time delay performance and without need for special manufacturing equipment-or for inert gas conditions.

1 . A heat activated power source comprising: 
 an electrically conductive shell extended along a longitudinal axis;    a heat activated electrolyte element;    a cathode element;    wherein said anode element, said electrolyte element, and said cathode element are stacked in said order along said longitudinal axis in said shell, and as a whole form an unitary body;    wherein said heat activated electrolyte element is switchable from an ion-isolative ground state to an ion-conductive active state by means of a heat energy pulse exceeding a threshold energy level;    wherein a first element of said anode element and said cathode element is an electrode element that is electrically insulated from said shell; and    wherein a second element of said anode element and said cathode element is electrically interconnected with said shell and comprises a heat energy amplifying material that is operative to ignite in response to a heat energy signal lower than said threshold energy level and, when ignited, to provide said electrolyte element with a heat energy pulse exceeding said threshold energy level;    such that said electrode element and said shell form two terminals between which a voltage is supplied when a heat energy signal lower than said threshold energy level is received by said second element.    
   
   
       2 . A heat activated power source according to  claim 1 , where in the cathode element is said first element and wherein the anode element is said second element.  
   
   
       3 . A heat activated power source according to  claim 1 , wherein the anode element is said first element and wherein the cathode element is said second element.  
   
   
       4 . A heat activated power source according to  claim 1 , wherein said heat activated electrolyte element comprises a compound that is chosen from the group consisting of LiAlCl 4 , LiBF 4 , LiCl, and LiBr.  
   
   
       5 . A heat activated power source according to  claim 1 , wherein said heat activated electrolyte element comprises a granulated compound or a compound in a crystalline or polycrystalline state.  
   
   
       6 . A heat activated power source according to  claim 1 , wherein said cathode element comprises a compound that is chosen from the group consisting of tungsten, molybdenum, tin lead, platinum, palladium, silver, and gold.  
   
   
       7 . A heat activated power source according to  claim 1 , wherein said cathode element comprises a compound that is chosen from the group consisting of: aluminum, zinc, magnesium, and iron.  
   
   
       8 . A heat activated power source according to  claim 1 , wherein said anode element comprises a compound that is chosen from the group consisting of: aluminum, zinc, magnesium, and iron.  
   
   
       9 . A heat activated power source according to  claim 1 , wherein said anode element comprises a compound in the form of compressed powder.  
   
   
       10 . A heat activated power source according to  claim 1 , wherein said anode element is constituted by a solid body.  
   
   
       11 . A heat activated power source according to  claim 1 , wherein said second element comprises an ionically active material other than the heat energy amplifying material.  
   
   
       12 . A heat activated power source according to  claim 1 , wherein said second element comprises one homogenous material only, which is heat energy amplifying and ionically active.  
   
   
       13 . A heat activated power source according to  claim 1 , further comprising an electrically insulating sleeve surrounding said first element and thus insulating it from the shell.  
   
   
       14 . A heat activated power source according to  claim 1 , wherein said second element is operative to ignite by a heat energy signal supplied from a shock tube.  
   
   
       15 . A heat activated power source according to  claim 1 , where in said electrolyte element requires a temperature above 200° C. in order to change state from said ion-isolative ground state to said ion-conductive active state.  
   
   
       16 . A detonator comprising a heat activated power source according to  claim 1 , and electronic delay circuitry, and a pyrotechnical detonator charge, wherein said electronic delay circuitry is operative to input electrical current from said power source and to output an electrical initiation signal initiating said pyrotechnical detonator charge.  
   
   
       17 . A detonator according to  claim 16 , further comprising an initiator that is operative to initiate said electrical initiation signal.  
   
   
       18 . A detonator according to  claim 16 , wherein said electronic delay circuitry comprises a capacitor operative to store electrical current from the power source during a delay time of said electronic delay circuitry.  
   
   
       19 . A detonator according to  claim 16 , further comprising a metallic capsule containing said electronic delay circuitry, said power source, and said detonating charge, and furthermore forming part of the power source shell, whereby the metallic capsule serves as an electrical connector element between the second element of said power source and said electronic delay circuitry.  
   
   
       20 . A detonator system comprising a detonator according to  claim 16  and shock tub, wherein said shock tube is interconnected with said power source and, is operative to ignite said second element in said heat activated power source.  
   
   
       21 . A method of manufacturing a heat activated power source according to  claim 1 , wherein each of the first element, the second element, and the electrolyte element is separately pressed into the shell.