Hydrogen storage alloy, preparation process thereof, and hydrogen storage device

Abstract

The hydrogen storage alloy has, as a main phase thereof, a bcc structure phase having a composition represented by Ti x Cr y V z X w wherein 3/2≦y/x≦3/1, 50≦z≦75 mol %, 0≦w≦5 mol %, and x+y+z+w=100 mol %, and X represents any one or more selected from Al, Si, and Fe. The hydrogen storage device is a device using the alloy. The preparation process of a hydrogen storage alloy includes the steps of: melting/casting raw materials mixed to give the composition represented by Ti x Cr y V z X w ; heat-treating an ingot obtained in the melting/casting step; and subjecting the heat-treated ingot to a hydrogen storing/releasing treatment at least once to activate the ingot.

1 . A hydrogen storage alloy comprising, as a main phase thereof, a bcc structure phase having a composition represented by the following formula (1):
   Ti x Cr y V z X w   (1)   wherein, 3/2≦y/x≦3/1, 40≦z≦75 mol %, 0≦w≦5 mol %, and x+y+z+w=100 mol %, and X represents any one or more selected from Al, Si, and Fe.   
     
     
         2 . The hydrogen storage alloy according to  claim 1 , wherein 3/2<y/x≦3/1 and 50≦z<70 mol %. 
     
     
         3 . The hydrogen storage alloy according to  claim 2 , wherein 55≦z<70 mol %. 
     
     
         4 . The hydrogen storage alloy according to  claim 2 , wherein 3/2<y/x≦3/1.2. 
     
     
         5 . The hydrogen storage alloy according to  claim 2 , wherein 3/2<y/x≦3/1.2 and 55≦z<70 mol %. 
     
     
         6 . The hydrogen storage alloy according to  claim 2 , wherein 3/1.65<y/x≦3/1.35 and 60≦z≦68 mol %. 
     
     
         7 . The hydrogen storage alloy according to  claim 1 , wherein 3/2≦y/x≦3/1 and 70<z≦75 mol %. 
     
     
         8 . A preparation process of a hydrogen storage alloy comprising:
 A melting/casting step of melting/casting raw materials mixed to give a composition represented by the following formula (1):
   Ti x Cr y V z X w   (1) 
   wherein 3/2≦y/x≦3/1, 40≦z≦75 mol %, 0≦w≦5 mol %, x+y+z+w=100 mol %, and X represents any one or more selected from Al, Si, and Fe;   a heat-treating step of heat-treating an ingot obtained in the melting/casting step; and   an activation step of activating the heat-treated ingot by subjecting the ingot to a hydrogen storing/releasing treatment at least once.   
     
     
         9 . A hydrogen storage device, comprising:
 the hydrogen storage alloy according to  claim 1 ,   a container for placing the hydrogen storage alloy therein, and   a heat exchanger for controlling the temperature of the hydrogen storage alloy placed in the container.