Patent Document

This is a divisional of U.S. Ser. No. 12/252,794 filed on Oct. 16, 2008, now U.S. Pat. No. 8,163,408, from which priority is claimed. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to providing pressure relief in batteries. 
     BACKGROUND 
     Batteries are used for many applications, including to power portable consumer electronics devices such as wireless computers and cellular phones. Because gases can build up during battery operation, pressure relief structure, be it a relief valve or simple score in the battery casing designed to fail before the rest of the casing, typically is provided. 
     As understood herein, however, batteries can and do catastrophically fail notwithstanding the pressure relief features because the anode/cathode structure inside the casing can warp sufficiently to block the gas path to the pressure relief feature. 
     SUMMARY OF THE INVENTION 
     A battery has an outer casing and an anode/cathode assembly within the casing. The assembly includes plural anodes and cathodes and electrolyte therebetween. At least one pressure relief feature is associated with the casing. A channel preservation element that is sufficiently rigid to preserve at least one gas passageway to the pressure relief feature under conditions of anode/cathode assembly warpage is also provided. 
     The channel preservation element can be disposed between the casing and the assembly. In addition or alternatively, the channel preservation element can be centrally disposed within the assembly. The channel preservation element may include a mesh. 
     In some embodiments the channel preservation element includes at least one concavity or convexity formed in the outer casing. In other embodiments the channel preservation element includes plural round channels. In still other embodiments the channel preservation element includes plural non-round channels. 
     In another aspect, a battery has a battery casing and means for providing pressure relief from gas build up in the battery casing. Means are provided for ensuring that at least one gas passageway exists in the casing to the means for providing pressure relief. 
     In another aspect, a method for providing pressure relief from gas build up in a battery includes providing a channel preservation element sufficiently rigid to preserve at least one gas passageway under operating conditions in a battery. The method also includes disposing the element between a casing and a jelly roll and/or centrally in the jelly roll such that the channel communicates with a pressure relief feature. The “or” in “and/or” is intended to be the exclusive form and would not require both options to be present at the same time. 
     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 
         FIG. 1  is a side elevational view of an example non-limiting battery in accordance with present principles; 
         FIG. 2  shows two top plan views showing pie-shaped segments of otherwise disk-shaped cross-sections the battery to illustrate various channel-preserving structures; 
         FIG. 3  shows a battery and a channelled tape that can be used between the jelly roll and casing of the battery in an exploded enlarged relationship therewith for illustration; 
         FIG. 4  shows another example embodiment of a battery with channel preservation element; 
         FIG. 5  is a plan view of a battery with centrally-disposed channel preservation element; 
         FIG. 6  is a plan view of a battery with both a central and an outer channel preservation element; and 
         FIGS. 7-10  are enlarged views of segments of the battery of  FIG. 6  illustrating further example channel preservation elements. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to  FIG. 1 , a battery  10  that can incorporate one or more of the below-discussed battery cells may be removably engaged with an electronic component  11  such but not limited to a notebook computer, wireless telephone, vehicle electric system, etc. to power internal parts thereof such as a processor, visual display, etc. Typically the battery  10  is engaged with a battery well or receptacle of the component  11 . The battery  10  may be rechargeable and may be a Lithium-ion battery. The structure of the battery may be, without limitation, cylindrical or prismatic. 
     The battery  10  in  FIG. 1  has a jelly roll  12  and a casing  14 . By “jelly roll,” is meant the cathode-anode-electrolyte assembly internal to the outer casing of the battery. Generally, a gas vent channel may be established in the center void of a jelly roll and/or between a jelly roll and an outer casing by a channel-preserving structure such as the examples shown herein. In non-limiting examples, the channel-preserving structure may be established by an electrically insulative flame-proof fabric mesh or a metal or plastic cage-like structure. 
     Moving on, the battery  10  has a pressure relief feature  16 , the pressure relief feature  16  being capable of allowing gas to exit the battery  10 . Generally, a jelly roll contained in a battery may expand or warp inside a casing because of excessive heat, stress, or many other factors. It is this expansion that causes a gas vent channel to become blocked, disallowing gas from reaching a pressure relief feature. 
     Thus, at least one gas vent channel  18  is either annularly disposed between the jelly roll  12  and the casing  14  and/or centrally disposed in a void  19  of the jelly roll  12 , the gas vent channel  18  being protected by a preservation element  20 . The preservation element  20  is sufficiently rigid so as to prevent expansion or warpage of the jelly roll  12  into the channel  18 , in a way that would completely block the channel  18 . 
     The rigid structure of the preservation element  20  prevents the jelly roll  12  from expanding to the point of completely blocking the pressure relief channel. As indicated above, if the jelly roll  12  were to unduly expand or warp for any reason, the channel  18  may become partially or completely blocked, thereby impeding gas from traveling through the channel  18  toward the pressure relief feature  16 . Further, if the channel  18  were to become blocked, the trapped gas may result in many unintended consequences such as battery malfunction, battery explosion, or the battery catching on fire, to list a few. Thus, a rigid, fixed path for gas to reach the pressure relief feature  16  is critical to the present invention. 
       FIG. 2  shows two partial cross sectional views of different, non-limiting configurations for a preservation element placement in relation to a channel to prevent a jelly roll from partially or totally blocking the channel. In both instances shown in  FIG. 2 , the preservation element is disposed between a battery casing and a jelly roll. 
     In the first non-limiting embodiment shown on the left in  FIG. 2 , a preservation element  22  is disposed within a channel  24  and is placed between by an outer casing  26  and a jelly roll  32 , where the rigid structure of the preservation element  22  maintains the void space in the channel  24  between the element  22  and the casing. Specifically, as shown the periphery of the element  22  has a series of rounded nodules facing the cylindrical wall of the casing to establish a series of longitudinal channels therebetween. 
     Still with reference to  FIG. 2 , another non-limiting configuration for a preservation element placed in a channel is shown. In this instance, an internally porous preservation element  30  encases at least one channel  28  and is placed between the jelly roll  32  and the outer casing  26 . Thus, the rigid structure of the preservation element  30  surrounding at least one channel  28  prevents the jelly roll  32  from expanding or warping into void channel space which must remain vacant for gas to reach a pressure relief feature. 
     Moving to  FIG. 3 , yet another non-limiting embodiment of a channel preservation element is shown. In both the cross sectional view and side view provided in  FIG. 3 , a battery  34  has a jelly roll  36 , at least one gas vent channel  38 , and an outer casing  40 . The battery  34  also has a channel preservation element  42  that is sufficiently rigid to preserve at least one gas passageway to a pressure relief feature. Distinguishing  FIG. 3 , the channel preservation element  42  is disposed between the jelly roll  36  and casing  40  and may be a substrate such as tape that forms the channel(s)  38  which are longitudinal relative to the battery  34 . Further, the longitudinal channel(s) created by the preservation element  42  may be either concave or convex in shape against to the casing  40 . 
     Now referencing  FIG. 4 , a channel preservation element particularly for a non-limiting prismatic-shaped battery is shown. In the  FIG. 4  cross sectional view, the battery  44  has a jelly roll  46 , a casing  48  and a pressure relief feature  50  such as a pressure relief valve or weakened portion of the casing. Further, the battery  44  has at least one channel  52  located between the jelly roll  46  and casing  48 , and the channel  52  is maintained by a preservation element  54 . The arrows in  FIG. 4  represent various directions gas may travel through the channel  52  to reach the pressure relief feature  50 , where the gas may then exit the prismatic-shaped battery  44 . The channels  52  established by the channel preservation element  54  are, as shown, sinusoidal or zig-zag in shape. 
     Another non-limiting embodiment of a channel preservation element particularly suited for a prismatic shaped battery is shown in  FIG. 5 .  FIG. 5  shows a rectangular cross section of the non-limiting embodiment. A battery  56  being substantially rectangular in shape has a jelly roll  58  and a casing  60 . Both the jelly roll  58  and casing  60  are also substantially rectangular in shape. The battery  56  also has a central gas vent channel  62  and a channel preservation element  63  to maintain the channel  62 . In  FIG. 5 , the jelly roll  58  surrounds the channel  62  and its preservation element  63 , which are both centrally disposed within the battery  56 . The element  63  may be established by, without limitation, a tube that is separate from the jelly roll and that is made of steel, aluminum, plastic, etc. that is loaded onto the mandrel around which the jelly roll is wrapped, with the tube being left in place after the mandrel is removed as indicated by the holes in the element  63 , or the element  63  may be a porous core such as, for example, a fabric mesh as described above that is folded upon itself in several layers. 
     Moving to  FIG. 6 , one non-limiting rectangular or square battery  64  has a jelly roll  66  and an outer casing  68 , both substantially similar in function to those in previous non-limiting embodiments provided above. The battery  64  also has at least one channel preservation element  70  which may either be centrally disposed within the battery  64  and/or disposed between the jelly roll  66  and outer casing  68 . 
       FIGS. 7-10  show various example channel configurations that may be used in the channel preservation element  70 . While  FIGS. 7-10  show various channel configurations in inner and outer channel preservation elements, it is to be understood that a configuration shown in the case of an outer element may be used for an inner element and vice -versa. 
     In  FIG. 7 , an outer channel preservation element  70   a  is formed with small circular shaped channels  72 , and an inner channel preservation element  70   b  is formed with relatively larger circular shaped channels  74  to maintain an unobstructed path for gas to travel to the pressure relief feature of the battery  64 . 
     Alternatively,  FIG. 8  shows that an inner channel preservation element  70   c  may be formed with plural series of four triangular channels  76 , with each series of four being arranged in a diamond pattern as shown. An example outer channel preservation element  70   d  may be formed with plural series of triangular channels  78 , with each series including two right triangles with their hypotenuses facing each other. 
       FIG. 9  shows yet another non-limiting rectangular embodiment of a channel design formed in a channel preservation element  70   e , in which plural channels  80  of rectilinear cross-section are arranged in multiple rows as shown. An outer channel preservation element  70   f  may also be provided and formed with multiple rounded nodules  82  on its outer periphery, facing the casing  68 , to establish channels  84  between the casing  68  and nodules  82 . The nodules  82  may contact the casing  68  as shown. 
       FIG. 10  shows yet another channel preservation element  70   g  disposed centrally in the battery and establishing two rows of diamond-shaped channels  86 , while an outer channel preservation element  70   h  includes a single row of diamond-shaped channels  88 . 
     While the particular BATTERY WITH PRESSURE RELIEF CHANNEL 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.

Technology Category: 5