Abstract:
The present invention discloses a hydrogen storage device. The hydrogen storage device includes a first casing, at least one hydrogen container, at least one stress buffering unit, and a second casing. The hydrogen container is set inside the first casing. The stress buffering unit is set between the hydrogen container and the first casing. The second casing surrounds the first casing forming a second space to contain heat transfer media, thereby controlling the temperature of the hydrogen container. While the hydrogen storage materials loaded in the hydrogen container absorb hydrogen gas, the stress buffering unit can eliminate the stress caused by the volume expansion of the hydrogen storage materials so as to prevent the first casing from distortion and deformation. Thus, the hydrogen gas can be stored efficiently and safely.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to hydrogen storage devices, and more particularly, to a hydrogen storage device that stores hydrogen gas efficiently and safely. 
         [0003]    2. Description of Related Art 
         [0004]    Currently, hydrogen gas, which is used in fuel batteries, need to be stored in hydrogen storage devices. However, hydrogen gas is typically stored by means of hydrogen storage materials. One type of such hydrogen storage materials is metal hydride, which, in comparison with erstwhile approaches where hydrogen gas was liquefied under high pressure, is less likely bring about the problem of leakage and related dangers caused by mass hydrogen gas. 
         [0005]    Typically, existing hydrogen storage devices are made by filling hydrogen storage alloy powder in the device with a certain vacant space reserved for the expansion of the hydrogen storage alloy powder. When absorbing hydrogen gas, the hydrogen storage alloy powder expands in volume and the particles of the powder jostle mutually. Consequently, the casing of the hydrogen storage device may deform due to the stress caused thereby. In addition, absorption of hydrogen accompanies the exothermic effect, which raises the temperature in the device and in turn reduces the efficiency of absorption. Hence, how to effectively disperse the generated heat is also an issue to be considered in designing hydrogen storage devices. 
         [0006]    Moreover, after repeated absorption and desorption of hydrogen, incineration and explosion are likely to happen to the hydrogen storage alloy powder. At this time, if the container receiving the hydrogen storage alloy powder is not designed with appropriate reserved space and fixing means, the overall service life of the hydrogen storage device can be significantly reduced. In view of the foregoing problems, designing a hydrogen storage device with reduced material costs and enhanced storage capacity of hydrogen storage alloy powder, that is also capable of effective long-term hydrogen gas storage, while ensuring the safety, efficiency, economic benefits, and convenience of hydrogen storage is an aim to be achieved. 
       BRIEF SUM MARY OF THE INVENTION 
       [0007]    The present invention provides a hydrogen storage device, which is equipped with a stress buffering unit and thereby eliminates the distortion and deformation of a hydrogen container thereof caused by expanded hydrogen storage material in hydrogen absorption. 
         [0008]    The present invention provides a hydrogen storage device, which is provided with a flow channel that assists a heat transfer medium therein in performing heat exchange so as to modulate the temperature variation of the hydrogen storage material and in turn ensure effective absorption and desorption of hydrogen. 
         [0009]    In order to achieve the above objectives, the present invention further provides a hydrogen storage device for storing hydrogen gas. The hydrogen storage device comprises: a first casing formed therein within a first space and formed thereon with a first opening that allows the first space to intercommunicate with an external environment; at least one hydrogen container set inside the first space for receiving a hydrogen storage material, wherein the hydrogen gas enters the first space from the external environment through the first opening and comes into contact with the hydrogen storage material for being stored; at least one stress buffering unit arranged between each said hydrogen container and the first casing for buffering a stress caused by the hydrogen storage material and acting on the hydrogen container; and a second casing surrounding the first casing to define a second space within the first casing, wherein the second casing has an inlet valve and an outlet valve that allow the second space to intercommunicate with the external environment, and a flow channel is defined between the inlet valve and the outlet valve in the second space for allowing at least one heat transfer medium to flow into the second space from the external environment through the inlet valve and to flow out of the second space through the outlet valve so that by heat exchange of the heat transfer medium, temperature of the hydrogen container is modulated. 
         [0010]    In order to achieve the above objectives, the present invention further provides a hydrogen storage device for storing hydrogen gas. The hydrogen storage device comprises: a first casing formed therein with a first space and formed thereon with an opening that allows the first space to intercommunicate with an external environment; at least one hydrogen container set inside the first space for receiving a hydrogen storage material, wherein the hydrogen gas enters the first space from the external environment through the opening and comes into contact with the hydrogen storage material for being stored; and at least one stress buffering unit arranged between each said hydrogen container and the first casing for buffering a stress caused by the hydrogen storage material and acting on the hydrogen container. 
         [0011]    By implementing the present invention, at least the following progressive effects can be achieved: 
         [0012]    1. With the stress buffering unit, the hydrogen container is prevented from distortion and deformation that otherwise might be caused by stress out of volume expansion of the hydrogen storage materials during hydrogen absorption. 
         [0013]    2. By the heat exchange of the heat transfer medium, the temperature of the hydrogen storage material is controllable and in turn, effective absorption and desorption of hydrogen can be ensured. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    A detailed description of further features and advantages of the present invention is given below so that a person skilled in the art can understand and implement the technical contents of the present invention and readily comprehend the objectives and advantages thereof by reviewing the disclosure of the present specification and the appended claims in conjunction with the accompanying drawings, in which: 
           [0015]      FIG. 1  depicts a first embodiment of a hydrogen storage device according to the present invention; 
           [0016]      FIG. 2  is a vertical sectional view of the hydrogen storage device taken along Line A-A of  FIG. 1 ; 
           [0017]      FIG. 3  is a transverse sectional view of the hydrogen storage device taken along Line B-B of  FIG. 1 ; 
           [0018]      FIG. 4  shows a second embodiment of the hydrogen storage device according to the present invention; 
           [0019]      FIG. 5  provides a third embodiment of the hydrogen storage device according to the present invention; 
           [0020]      FIG. 6  illustrates a fourth embodiment of the hydrogen storage device according to the present invention; and 
           [0021]      FIG. 7  exhibits a fifth embodiment of the hydrogen storage device according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Referring to  FIG. 1  through  FIG. 3 , the present embodiment shows a hydrogen storage device  100  for storing hydrogen gas. The hydrogen storage device  100  includes: a first casing  10 , at least one hydrogen container  20 , at least one stress buffering unit  30 , and a second casing  40 . 
         [0023]    As shown in  FIG. 2 , the first casing  10  is formed therein with a first space  11  and thereon with a first opening  12 . The first opening  12  allows the first space  11  to intercommunicate with the external environment, and allows hydrogen gas to be introduced into the first space  11  therethrough. The first casing  10  may include at least one depressed portion  13 , which is formed by depressing the first casing  10  inward the first space  11 . The depressed portion  13  may be shaped as a column. 
         [0024]    The hydrogen container  20 , which may be a top-opened annular container, is set inside the first space  11  for receiving a hydrogen storage material. Hydrogen gas is introduced into the first space  11  from the external environment by way of the first opening  12  and comes into contact with the hydrogen storage material in the hydrogen container  20  so that the hydrogen gas is stored. The first space  11 , depending on the volume thereof; may include at least two said hydrogen containers  20 . In order to prevent volume expansion of the hydrogen storage material after hydrogen absorption from affecting the first casing  10  and to give the hydrogen storage material sufficient space to expand, the hydrogen containers  20  may be arranged in the first space  11  with a predetermined interval therebetween. 
         [0025]    The hydrogen storage material may be of the high-temperature type, middle-temperature type or low-temperature type, and may be made of hydrogen storage alloy or, more particularly, metal hydride. In the meantime, different types of hydrogen storage materials may be used. For this end, each said hydrogen container  20  is configured to receive hydrogen storage materials of different characteristics independently. 
         [0026]    The stress buffering unit  30  is arranged between each said hydrogen container  20  and the first casing  10  for buffering stress that acts on the hydrogen container  20  and is caused by the volume expansion of the hydrogen storage materials. The stress buffering unit  30  may be a spring unit  31 , a sponge unit, a metal elastic piece  32  or an elastomer. As shown in  FIG. 4 , the stress buffering unit  30  is a spring unit  31  made of metal and serves to connect the hydrogen container  20  to a lateral wall of the first casing  10 . The metal spring unit  31 , in addition to its function of buffering the stress caused by the volume expansion of the hydrogen storage materials, can further provide good thermal conductivity that facilitates heat transmission of the hydrogen storage materials during absorption and desorption of hydrogen gas. 
         [0027]    Alternatively, as shown in  FIG. 5 , the stress buffering unit  30  may be a metal elastic piece  32  in the form of a bent metal sheet. Therein, each metal elastic piece  32  has a camber apex  33  and two ends  34 . The camber apex  33  is connected with the hydrogen container  20 , and the ends  34  are fasten to the lateral wall of the first casing  10 . Since the metal elastic piece  32  is made of metal and thus has resilience, it can also provide the functions of heat transmission and buffering. 
         [0028]    Referring back to  FIG. 2  and  FIG. 3 , the second casing  40  surrounds the first casing  10  and defines a second space  41  with the first casing  10 . The second casing  40  further has an inlet valve  42  and an outlet valve  43  that allow the second space  41  to intercommunicate with the external environment. Meantime, a flow channel  44  is defined between the inlet valve  42  and the outlet valve  43  in the second space  41  for allowing at least one heat transfer medium to flow into the second space  41  from the external environment by way of the inlet valve  42  and flow out of the second space  41  through the outlet valve  43 . 
         [0029]    When the first casing  10  includes the depressed portion  13 , the flow channel  44  may be made as a curved flow channel  44 , and the depressed portion  13  may further include a spoiler  45 . The spoiler  45  is settled on the second casing  40  and in parallel with lateral walls of the depressed portion  13  so that the heat transfer medium can flow into the depressed portion  13 . Thus, heat generated by the hydrogen storage material near the center of the hydrogen storage device  100  can be also effectively dispersed through heat exchange. 
         [0030]    As shown in  FIG. 2 , arrows indicate the direction of the heat transfer medium flowing in the second space  41 . The heat transfer medium flows into the second space  41  through the inlet valve  42 , and then passes the curved flow channel  44  composed of the spoiler  45  and the depressed portions  13  before flowing out of the second space  41  by way of the outlet valve  43 . As a result the heat transfer medium can perform heat exchange to both the inner and outer hydrogen storage material in the hydrogen container  20 , so as to modulate the temperature of the hydrogen container  20 . Therein the heat transfer medium may be one or a combination of any of water, gas, oil and a hydrocarbon. 
         [0031]    In the hydrogen storage device  100 , temperature modulation of the hydrogen container  20  relies on heat transmission of both the first casing  10  and the second casing  40 . Therefore, the first casing  10  and the second casing  40  may be independently made of different heat transfer materials. However, for further isolating the overall hydrogen storage device  100  from the external temperature, additional heat-insulation design may be adopted. As shown in  FIG. 2 , a heat insulation layer  50  may be further implemented to surround the second casing  40 . Or, as shown in  FIG. 4 , a third casing  60  made of a heat transfer material independently may be additionally provided outside the second casing  40 . The third casing  60  surrounds the second casing  40  and defines a third space  61  with the second casing  40 . The third space  61  may also contain a heat insulation unit (not shown) for reducing the heat transmission between the external environment and the hydrogen container  20 . 
         [0032]    Referring to  FIG. 6  and  FIG. 7 , there is another embodiment of the present invention. The hydrogen storage device  100 ′ includes a first casing  10 , at least one hydrogen container  20 , and at least one stress buffering unit  30 . 
         [0033]    As shown in  FIG. 6  and  FIG. 7 , the first casing  10  is also formed therein with a first space  11  and formed thereon with an opening  14  that allows the first space  11  to intercommunicate with the external environment and allows hydrogen gas to be introduced into the first space  11  therethrough. 
         [0034]    The hydrogen container  20  may be in the shape of a disk and set inside the first space  11  for receiving a hydrogen storage material. The first casing  10  may include at least two said hydrogen containers  20  that are arranged in the first space  11  with a predetermined interval therebetween. The hydrogen container  20  may independently receive hydrogen storage materials of different characteristics. Therein, hydrogen gas is introduced into the first space  11  from the external environment through the opening  14  on the first casing  10  and comes into contact with the hydrogen storage materials so that the hydrogen gas can be stored. Moreover, the hydrogen storage materials may be of the high-temperature type, middle-temperature type, or low-temperature type. 
         [0035]    The stress buffering unit  30  is arranged between each said hydrogen container  20  and the first casing  10  for buffering stress acting on the hydrogen container  20  during absorption and desorption of the hydrogen gas. The stress buffering unit  30  may be a spring unit  31 , a sponge unit, a metal elastic piece  32 , or an elastomer. 
         [0036]    As shown in  FIG. 7 , the stress buffering unit  30  is a spring unit  31  made of metal and connecting between the hydrogen container  20  and the first casing  10 . The metal spring unit  31  can not only buffer the stress caused by the volume expansion of the hydrogen storage materials, but also provide good thermal conductivity that facilitates heat transmission of the hydrogen storage materials during absorption and desorption of hydrogen gas. The stress buffering unit  30  may alternatively be a metal elastic piece  32  composed of a bent metal sheet as shown in  FIG. 5 . 
         [0037]    The foregoing embodiments are illustrative of the characteristics of the present invention so as to enable a person skilled in the art to understand the disclosed subject matter and implement the present invention accordingly. The embodiments, however, are not intended to restrict the scope of the present invention. Hence, all equivalent modifications and variations made in the foregoing embodiments without departing from the spirit and principle of the present invention should fall within the scope of the appended claims.