Method for storing hydrogen in an hybrid form

Abstract

A method for storing hydrogen which combines the advantages of at least two known methods for storing hydrogen, selected amongst the methods for storing hydrogen in a gaseous form, in a liquid form and in a solid form. More specifically, the above method consists in coupling and using in a single tank at least two of the methods for storing hydrogen mentioned hereinabove, namely: A) the method for storing hydrogen in a gaseous form; B) the method for storing hydrogen in a liquid form; and C) the method for storing hydrogen in a solid form, in volume or surface, preferably by means of a suitable hydride. The only condition is that each of the above methods be used for storing at least 5% by weight of the total amount of hydrogen to be stored within a tank. Such a method permits to obtain fast release of hydrogen whenever required while ensuring high storage capacities. It also permits to satisfy transitory periods especially during the accelerations of a hydrogen-powered automotive vehicle.

1 . A method for storing hydrogen in a hybrid form, comprising coupling and using within a single tank at least two hydrogen storage means selected from the group consisting of: 
 a) means for storing hydrogen in a gaseous form    b) means for storing hydrogen in a liquid form; and    c) means for storing hydrogen in a solid form by absorption or adsorption,    with the proviso that each of the means for storing hydrogen that are used, is sized to store at least 5% by weight of the total amount of hydrogen stored within the tank.    
     
     
         2 . The method according to  claim 1 , wherein the means that are coupled and used, include said means for storing hydrogen in a gaseous form and said means for storing hydrogen in solid form with a metal hydride.  
     
     
         3 . The method according to  claim 2 , wherein the metal hydride has an equilibrium plateau pressure higher than 40 bar at the operating temperature of the tank.  
     
     
         4 . The method according to  claim 3 , wherein the hydride is a Ti- or alanate (AlH x ) based hydride.  
     
     
         5 . The method according to  claim 1 , wherein the means that are coupled and used, include said means for storing hydrogen in a liquid form and said means for storing hydrogen in a solid form with a metal hydride.  
     
     
         6 . A hybrid tank for storing hydrogen in both liquid and solid forms, comprising two concentric containers, one of said containers hereinafter called “inner container” being located within the other one which is hereinafter called “outer container”, said containers being separated by an insulating sleeve for maintaining the inner container at low temperature, said inner container being used for storing hydrogen in a liquid form, said outer container being in direct communication with the inner container and containing a metal hydride for storing hydrogen in a solid form.  
     
     
         7 . The hybrid tank according to  claim 6 , wherein the hydride that is used in the outer container is an hydride having low equilibrium plateau pressure at the operating temperature of the tank.  
     
     
         8 . The hybrid tank according to  claim 7 , wherein the hydride that is used is selected from the group consisting of NaAlH 4 , LiAlH 4 , LaNi 5 H 6  and MgH 2 .  
     
     
         9 . The hybrid tank according to  claim 6 , wherein the hydride within the outer container is an hydride having a high equilibrium plateau pressure at the operating temperature of the tank.  
     
     
         10 . The hybrid tank according to  claim 9 , wherein the hydride is selected from the group consisting of TiCr 1.8 , TiMn 2-y , Hf 2 Cu, Zr 2 Pd, TiCu 3  and V 0.855  Cr 0.145 .  
     
     
         11 . A hybrid tank for storing hydrogen in both solid and gaseous forms, comprising: 
 a container having a metallic liner or inner wall covered with a polymeric outer shell, said container being devised to store hydrogen in gaseous form at a high pressure and to receive and store a metal hydride in order to also store hydrogen in solid form;    at least one heat pipe mounted in the container to allow circulation of a heat carrying fluid within said container; and    a heat exchanger located within the container in order to ensure thermal connection between said at least one heat pipe and the hydride.    
     
     
         12 .The hybrid tank according to  claim 11 , wherein: 
 the container is cylindrical and provided with an axial opening;    the tank comprises only one of said at least one heat pipe which is inserted into the container through the opening thereof and extends axially within said container; and    the heat exchanger consists of at least one element selected from the group consisting of metallic grid, fibers or porous metallic structure extending transversally within the container, each of said at least one grid being in direct contact with the axial heat pipe, the metallic liner of the container and the hydride.    
     
     
         13 . The hybrid tank according to claim  12 , wherein the hydride that is used in the outer container is an hydride having low equilibrium plateau pressure at the operating temperature of the tank.  
     
     
         14 . The hybrid tank according to  claim 13 , wherein the hydroxide that is used is selected from the group consisting of NaAlH 4 , LiAlH 4 , LaNi 5 H 6  and MgH 2 .  
     
     
         15 . The hybrid tank according to claim  12 , wherein the hydride within the outer container is an hydride having a high equilibrium state at the operating temperature of the tank.  
     
     
         16 . The hybrid tank according to  claim 15 , wherein the hydride is selected from the group consisting of TiCr 1.8  TiMn 2-y , Hf 2 Cu, Zr 2 Pd, TiCu 3  and V 0.855  Cr 0.145 .