Abstract:
A battery has a casing holding plural cells and a mesh wrapped around the cells to contain pieces of an exploding cell within the casing. To prevent overpressurization of the casing from the gas emitted by an exploding cell, a pressure relief feature is provided that allows gas to pass through battery casing.

Description:
I. FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to battery cell containment and venting in applications such as portable computers and motor vehicle. 
       II. BACKGROUND OF THE INVENTION 
       [0002]    Batteries, including Lithium-Ion batteries, are extensively used in laptop computers, cellular phones, and many other types of electrical devices. Particularly with respect to the preferred Lithium-Ion batteries, these batteries may be made at a relatively low cost and have a relatively high electrical storage capacity. 
         [0003]    As electrical devices become more complex and thus consume more electricity, such as is the case with cellular phones, manufacturers have included high powered batteries such as Lithium-Ion batteries with their product. However, as understood herein the high powered battery cells included in such batteries may cause unintended battery malfunctions. Examples of such malfunctions include battery cell explosions, ruptures, and venting (a forced expulsion of gases). 
       SUMMARY OF THE INVENTION 
       [0004]    A battery has plural battery cells and an outer casing holding the cells. A mesh surrounds the cells to contain cell parts should a cell explode. The mesh is porous to gas emitted by the cells such that the gas can pass through the mesh to the casing. At least one pressure relief feature is arranged to permit gas to pass through the casing when pressure in the casing exceeds a threshold. 
         [0005]    In some embodiments the casing has at least one first portion and a second portion, with the first portion being structurally weaker than the second portion to establish the pressure relief feature. In other embodiments the pressure relief feature is established by at least one pressure relief valve, e.g., a one-way valve. 
         [0006]    The mesh may be fire resistant. Furthermore, thermal barriers may be disposed between adjacent cells. A thermal barrier may include a ceramic plate. The battery may be used in a computer or a motor vehicle. 
         [0007]    In another aspect, a battery includes a mesh material wrapped around at least part of the battery and at least one relief feature capable of allowing gas to pass from a battery cell through battery casing. 
         [0008]    In another aspect, a method to contain pieces of an exploding battery cell within a battery casing while preventing overpressurization of the casing includes constraining the cell in the casing using structure within the casing and providing a gas vent through the casing. 
         [0009]    The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a block diagram in accordance with one non-limiting embodiment of a laptop computer using a battery; 
           [0011]      FIG. 2  is a schematic side view of a non-limiting embodiment of a battery with plural battery cells; 
           [0012]      FIG. 3  is a schematic side view of a non-limiting embodiment of a battery with a mesh overmolded onto an outer casing of a battery; 
           [0013]      FIG. 4  is a schematic top view of a non-limiting embodiment of a vehicle battery with a preventative mesh and at least one pressure relief feature; 
           [0014]      FIG. 5  is a schematic side view of a non-limiting embodiment of a vehicle battery with a preventative mesh and at least one pressure relief feature; and 
           [0015]      FIG. 6  is a block diagram of a general embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    Beginning initially with  FIG. 1 , a non-limiting embodiment of a portable computer  10  such as a laptop computer or notebook computer or personal digital assistant or mobile telephone is shown. While  FIG. 1  shows a computer application for present principles, as discussed below other applications are envisioned, including motor vehicle applications. 
         [0017]    The computer  10  has a display  12  capable of presenting electronic images to a user. The computer  10  also includes a keypad  14  and mouse pad  16  capable of receiving data input from a user. Further, the computer  10  includes data storage  18  capable of storing data and at least one processor  22  capable of executing logic. The computer  10  also has a preferably high powered battery  24  such as but not limited to a Lithium-ion battery which provides power to the computer  10 . 
         [0018]    Moving to  FIG. 2 , the battery  24  has plural battery cells  26  and an outer casing  28  holding the cells  26 . The battery  24  also has a mesh  30  that at least partially surrounds the cells  26 , providing support and containing various parts of the cells  26  should a cell explode or rupture. The mesh  30  may be both heat and fire resistant. Furthermore, the mesh preferably is porous to gas emitted by the cells such that the gas can pass through the mesh to the casing  28 . Further, the mesh  30  may electrically insulate the cells  26  in non-limiting embodiments. Also in non-limiting embodiments, the mesh  30  may be composed of high strength glass fiber mat, carbon fiber mat or metal grate. 
         [0019]      FIG. 2  also shows one or more thermal barriers  32  that may be disposed between adjacent cells  26 . In one embodiment the thermal barrier is established by at least one ceramic plate. 
         [0020]    Further, in the example embodiment shown at least one pressure relief feature  34  is associated with the casing  28 . The pressure relief feature  34  permits gas to pass through the casing  28  when pressure in the casing  28  exceeds a threshold. In some embodiments the pressure relief feature  34  may be established by a one-way pressure relief valve. In other embodiments the pressure relief feature may be established by a weakened portion of the casing wall, e.g., a portion of the casing wall that is thinner than other portions of the casing wall. 
         [0021]    Further still, the pressure relief feature  34  may be connected to an exhaust pipe  36 . The pipe  36  directs gas emerging through the pressure relief feature  34  to an intended location, for instance, to the exhaust system of a vehicle when the battery is used in automotive applications. Thus in one non-limiting implementation, if the battery  24  were a vehicle battery, the exhaust pipe  36  may connect to the vehicle&#39;s engine exhaust system so that gas from the battery  24  may be expelled from the vehicle. 
         [0022]    Now referencing  FIG. 3 , a non-limiting embodiment of an alternate mesh that is overmolded in a battery casing is shown. A battery  38  has a mesh  40 , with the mesh  40  being overmolded or embedded onto a casing  42  in a crisscross pattern in the non-limiting embodiment shown in  FIG. 3 . It is to be understood that the mesh  40  in all other essential respects is substantially similar in function and structure to the mesh  30  set forth above. 
         [0023]    As already mentioned in reference to  FIG. 3 , the mesh  40  may be overmolded or embedded into the casing  42 . It is to be understood that the mesh  40  may be overmolded or embedded in only part of the casing  42 . However, in certain non-limiting embodiments the mesh  40  may also be overmolded or embedded in the entire casing  42 . 
         [0024]    Moving on to  FIGS. 4 and 5 , a non-limiting application of the present invention as applied to a vehicle battery is shown. A battery  44  has plural cells  46  and an outer casing  48  holding the cells  46 . The battery also includes a mesh  50  represented in  FIG. 4  by dotted lines along the cell  46  periphery. It is to be understood that the mesh  50  is substantially similar in function and structure to the mesh  30  set forth above. 
         [0025]    As best shown in  FIG. 4 , the battery  44  also includes pressure relief features  52 . The pressure relief features  52  are arranged to permit gas to pass through the casing  48  and out of the battery  44  when pressure in the casing  48  exceeds a threshold. Further, the pressure relief feature  52  may in non-limiting embodiments be a one-way pressure relief valve and may also be connected to an exhaust pipe not shown. The exhaust pipe may then be connected to the vehicle&#39;s engine exhaust system to carry gas away from the battery  44 . 
         [0026]      FIG. 6  shows that the present battery may be removably engaged with an electronic component  112  such but not limited to a notebook computer, wireless telephone, vehicle electric system, etc. to power internal parts thereof such as a processor  114 , visual display  116 , etc. Typically the battery  10  is engaged with a battery well or receptacle  118  of the component  112 . The battery  10  may be rechargeable and may be a Lithium-ion battery. 
         [0027]    While the particular BATTERY CELL CONTAINMENT AND VENTING is herein shown and described in detail, it is to be understood that the subject matter which is encompassed by the present invention is limited only by the claims.