Abstract:
The subject invention provides a tray assembly for use in forming a sealed lead-acid battery system which houses multiple battery cells in horizontal positions for motive-power applications. In one aspect of the subject invention, the battery system includes a plurality of sealed lead-acid battery cells, and a housing having a plurality of walls which define an interior for accommodating the battery cells. At least one tray insert bears against a base of the housing which partitions the interior into at least two compartments for accommodating the battery cells. In a second aspect of the subject invention, a sealed lead-acid battery system for motive-power applications may be provided which utilizes at least one spacer partially disposed between two battery cells to cause separation thereof.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority of U.S. Provisional Application No. 60/302,641, filed Jul. 2, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    Tray assemblies are known in the prior art for maintaining multiple rechargeable battery cells (e.g., sealed vent-regulated lead-acid (VRLA) cells) in horizontal positions for motive-power applications. Motive-power applications include providing power, in rechargeable form, to Class 1 to Class 3 trucks, which include various automated guided vehicles (e.g., Class 1 and 2 trucks include electric rider trucks and electric narrow aisle trucks; Class 3 includes electric hand trucks (“pallet trucks”)). It has been found that by maintaining the battery cells in horizontal positions several benefits can be obtained including, but not limited to, maximizing acid wicking and minimizing plate stratification of cells.  
           [0003]    For example, U.S. Pat. No. 5,441,123 to Beckley, which issued Aug. 15, 1995, discloses a cell tray configured to house six lead-acid cells. The Beckley tray includes a cell enclosure area which is divided into at least three compartments by shelf members which are rigidly attached to the side walls of the cell enclosure area.  
           [0004]    With reference to U.S. Pat. No. 6,162,559 to Vutetakis et al., which issued Dec. 19, 2000, a tray assembly for holding battery cells in horizontal positions for motive-power applications is shown therein where battery cells are stacked one atop another, with a compression plate being located above the stack configured to apply compressive force downwardly on the entire stack to hold the cells in place. Because the compression plate needs to provide clamping force for all of the cells, the housing is not sub-divided into compartments.  
           [0005]    Although designs are known in the prior art for trays formed to maintain battery cells in horizontal positions for motive-power applications, there is a continuous need to provide simpler and easier-to-manufacture tray designs.  
         SUMMARY OF THE INVENTION  
         [0006]    To overcome the deficiencies of the prior art, the subject invention provides a tray assembly for use in forming a sealed lead-acid battery system which houses multiple battery cells in horizontal positions for motive-power applications. In one aspect of the subject invention, the battery system includes a plurality of sealed lead-acid battery cells, and a housing having a plurality of walls which define an interior for accommodating the battery cells. At least one tray insert bears against a base of the housing which partitions the interior into at least two compartments for accommodating the battery cells.  
           [0007]    More particularly, in a first embodiment of the first aspect of the subject invention, a box-shaped housing is provided along with at least one inverted U-shaped partition. The partition is dimensioned to slide into the housing with its downwardly depending legs bearing against the base of the housing and being in general face-to-face, or near face-to-face, contact with the side walls of the housing. When disposed within the housing, battery cells may be disposed below the cross member of the partition, as well as atop the cross member of the partition. To facilitate multiple compartments being defined within the enclosure, the partitions are formed to be stackable. As a further variation of the first embodiment, locking tabs may project from the ends of legs of the partitions, which are formed to register with corresponding locking holes located in the base of the housing and/or in a lower-stacked partition. The tabs and holes register with the partitions being fully slid into the housing.  
           [0008]    In a second, and most preferred, embodiment, a pre-assembled partition of at least one vertical member and one horizontal member is slid into the housing to define multiple compartments therein. Whereas, with a third embodiment of the invention, tubular partitions are provided which are formed to slide into, and stack within, the housing.  
           [0009]    In a second aspect of the subject invention, a sealed lead-acid battery system for motive-power applications may be provided which utilizes at least one spacer partially disposed between two battery cells to cause separation thereof. More particularly, in a fourth embodiment of the invention, T-shaped spacers may be provided to support edges of stacked battery cells. With this arrangement, portions of the spacers are urged between the cells and the side walls of the housing, with the main branches of the spacers being interposed between adjacent stacked cells.  
           [0010]    With all four embodiments of the subject invention, the tray inserts (i.e., partitions) and the spacers are removable and need not be rigidly fixed to the housing. Therefore, assembly of the subject invention is relatively quick and simple as compared to the prior art. The prior art requires either rigid mounting of the tray inserts or use of a compression plate. If some rigidity is required (e.g., to minimize vibration noise), the tray insert may be fixed to portions of the housing.  
           [0011]    These and other features of the invention will be better understood through a study of the following detailed description and accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    FIGS.  1 - 3  are perspective views of various tray assemblies formed in accordance with a first embodiment of the subject invention;  
         [0013]    [0013]FIGS. 4A and 4B are perspective views of a tray assembly formed in accordance with a second embodiment of the subject invention;  
         [0014]    [0014]FIG. 5 is a perspective view of a pre-assembled partition used in connection with the second embodiment of the subject invention;  
         [0015]    [0015]FIG. 6 is a perspective view of a tray assembly formed in accordance with a third embodiment of the subject invention;  
         [0016]    [0016]FIG. 7 is an elevational view of a partition used in connection with the third embodiment of the subject invention;  
         [0017]    [0017]FIG. 8 is a perspective view of a tray assembly formed in accordance with a fourth embodiment of the subject invention;  
         [0018]    [0018]FIG. 9 is a plan view of a spacer used in connection with the fourth embodiment of the subject invention; and  
         [0019]    FIGS.  10 - 12  are perspective views of an enclosed housing used in connection with the subject invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    The following is a description of various embodiments of the subject invention. With respect to all of the embodiments, a tray assembly for holding battery cells in horizontal positions for motive-power applications is described.  
         [0021]    With respect to FIGS.  1 - 3 , a first embodiment of the subject invention is shown. In particular, a tray assembly  10  is provided having a housing  12  with multiple compartments  14  defined therein for accommodating battery cells  18  in horizontal positions. The housing includes a base  15 , side walls  16 , and a cover  17 . Partitions  20  are provided which are formed to slide into the housing  12  and partially define the compartments  14 .  
         [0022]    Each of the partitions  20  is formed with an inverted U-shape having a transverse cross member  22  with downwardly depending legs  24 . The legs  24  are spaced apart approximately the same as the internal width of the housing  12  (i.e., the spacing between the side walls  16 ). Thus, upon sliding the partitions  20  into the housing  12 , the legs  24  will be in face-to-face, or near face-to-face, contact with the side walls  16  of the housing  12 . With use of multiple partitions  20 , the partitions  20  are stacked vertically, with the legs  24  of an upper-stacked partition  20  being supported by the cross member  22  of a lower-stacked partition  20 , whereas, the legs  24  of the lowest-stacked partition  20  will bear against the base  15 . As can be readily appreciated, the specific dimensioning of the housing  12  is a direct finction of the volume of the cells  18  to be stored therein (e.g., the volume of six of the battery cells  18 ). Likewise, the specific dimensioning of the partitions  20  is dictated by the volume of the compartments  14  (e.g., each compartment  14  is dimensioned to accommodate two vertically-stacked battery cells  18 ).  
         [0023]    Advantageously, loading applied to any of the cross members  22  will be transmitted to the base  15  via the legs  24  (and intervening partitions  20  depending on the stacked arrangement). As such, loading of upper-stacked battery cells  18  may be primarily, and directly, transmitted to the base  15 . In that manner, loading of a large stack of the battery cells  18  on lower-stacked battery cells  18  may be avoided.  
         [0024]    As a further variation, locking tabs  26  may be formed to extend from the ends of the legs  24  which are formed to register with locking holes  28  formed at the junctures of the cross members  22  and the legs  24  of the partitions  20 . The locking tabs  26  are sized and located to register with the locking holes  28  when stacking one of the partitions  20  atop another. Additionally, locking holes  28  may be formed in the base  15  of the housing  12 . The interengagement of the locking tabs  26  and the locking holes  28  restricts movement of the partitions  20 . It is preferred that the locking tabs  26  and the locking holes  28  be in registration with the partitions  20  being fully slid into the housing  12 .  
         [0025]    With the tray assembly  10  shown in FIG. 1, one stack of the battery cells  18  may be accommodated. As shown in FIGS. 2 and 3, the tray assembly  10  can be formed to accommodate two stacks of the battery cells  18 , or three stacks of the battery cells  18 . It is preferred that little free space about the battery cells  18  be provided within the tray assembly  10 . Other numbers of stacks, and partitions, are possible.  
         [0026]    A second, and most preferred, embodiment of the invention is shown in FIGS. 4A, 4B and  5 , wherein a tray assembly  200  is formed with the housing  202  having a pre-assembled partition  204  slidably disposed therein. The partition  204  divides the interior of the housing  202  into multiple compartments  206 . Although not shown, each of the compartments  206  is dimensioned to receive one or more of the battery cells and/or one or more vertical stacks of the battery cells.  
         [0027]    With reference to FIG. 5, the partition  204  is formed with at least one horizontal member  208  and one vertical member  210 . In one variation, as shown in FIG. 5, the members  208  and  210  intersect at locations spaced away from respective longitudinal edges  209  and  211  of the members  208  and  210 . Alternatively, as shown in FIG. 4B, the members  208  and  210  may be located to intersect at the longitudinal edge(s)  209 ,  211 . In either respect, the vertical member  210  bears against a base of the housing  202 . The members  208  and  210  are assembled together using any technique known to those skilled in the art. Once assembled, the entire partition  204  is slid into the housing  202 . To provide stability to the partition  204 , as shown in FIG. 4A, the edge dimensions (at the longitudinal edges  209  and  211 ) of the members  208  and  210  may be formed generally to the interior dimensions of the housing  202 , so as to be in bearing, or in near bearing, engagement therewith without excessive play. Alternatively, as shown in FIG. 4B, the partition  204  can be formed and arranged to define one or more open compartments  206 B which extend the height of the housing  202 . The number and configuration of the members  208  and  210  can be varied to define the size and quantity of the compartments  206 . For example, two of the horizontal members  208  may intersect the vertical member  210 , or vice versa, to define six of the compartments  206 ; or, two of the horizontal members  208  may intersect two of the vertical members  10  to define nine of the compartments  206 .  
         [0028]    Any loading applied to the partition  204  (e.g., by stacking battery cells on portions of the horizontal member(s)  208  in one or more of the compartments  206 ) will be primarily transmitted to the base of the housing  202  via the vertical member(s)  210 .  
         [0029]    As a further variation, a back plate  212  may be mounted to the rear of the members  208  and  210  to provide additional stability to the partition  204 . The back plate  212  may be bolted, or rigidly fixed in other manners, to the housing  202  (e.g., to a back plate of the housing  202  discussed below) for further stability and to minimize vibration noise.  
         [0030]    [0030]FIGS. 6 and 7 relate to a third embodiment of the subject invention wherein a tray assembly  300  is provided having a housing  302  with multiple tubular partitions  304  disposed therein. Each of the tubular partitions  304  defines a compartment  306  for receiving one or more of the battery cells and/or one or more vertical stacks of the battery cells.  
         [0031]    As shown in FIG. 7, each of the partitions  304  is tubular so as to have an uninterrupted form which extends about the compartment  306  thereof. In a preferred embodiment, the partitions  304  have rectangular profiles with generally parallel top and bottom  308  and  310 , and with a pair of generally parallel side walls  312 . The partitions  304  can be formed from seamless stock or from one or more sheets bent and welded.  
         [0032]    As with the previous embodiments, it is preferred that the side walls  312  be dimensioned to come into general face, or near face, contact with the housing  302  to be supported thereby. The dimensioning of the housing  302 , as well as the partitions  304 , are dictated by the number of battery cells to be accommodated and/or the number of stacks to be accommodated. The partitions  304  may be stacked with the lowest-most partition  304  bearing against a base of the housing  302  and upper-stacked partitions  304  being supported by adjacent partitions  304 . Loading applied to the tops  308  of the partitions  304  (e.g., from the weight of upper-stacked battery cells) will be primarily transmitted to a base of the housing  302  through the bottoms  310  and side walls  312  (and any intervening partitions  304 ).  
         [0033]    With reference to FIGS. 8 and 9, a fourth embodiment of the subject invention is shown wherein a tray assembly  400  is provided. The tray assembly  400  can be formed as a single, stand-alone unit, or formed from smaller stacked tray assemblies  400 A and  400 B. For illustrative purposes, reference will be made to the tray assembly  400 B. It is to be understood that the tray assembly  400 A is similarly structured.  
         [0034]    The tray assembly  400 B includes a housing  402  having a base  404 , side walls  406 , and a cover  408  formed to define a single compartment  410 . The compartment  410  is not partitioned into smaller compartments as with the other embodiments of the subject invention. Rather, battery cells  412  are held in a spaced apart relationship within the compartment  410  by elongated spacers  414 .  
         [0035]    As best shown in FIG. 9, each of the spacers  414  is cross-sectionally formed with a T-shape, having a cross piece  416  formed to define a space between the battery cells  412  and side walls  406  of the housing  402 , and a main branch  418  formed to be interposed between stacked battery cells  412  to define spaces therebetween. Preferably, two of the spacers  414  are spaced-apart and inwardly directed to cooperatively separate a pair of the battery cells  412 . It is preferred that the housing  402  be formed to tightly accommodate a stack of the battery cells  412  being spaced apart by the spacers  414 .  
         [0036]    The edge support provided by the spacers  414  is advantageously provided to the side walls of the battery cells  412  which are the strongest portions of the jars of the battery cells  412 . With the weight of the battery cells  412  being concentrated on the side walls of the jars, direct pressure on the plates of the battery cells  412  is minimized or altogether eliminated. Nevertheless, it can be appreciated that since the battery cells  412  are not fully supported by partitions, but rather have edge support from the spacers  414 , the height of the stack is preferably limited because of the limited edge support. It is desirable to avoid excessively high loading on the battery cells due to an excessive number of cells being stacked. Unlike the previous embodiments, no tray insert is provided in this embodiment which directly transmits load to the base of the housing from upper stacked cells. It is therefore preferred that, as described above, the stack be separated between the two tray assemblies  400 A and  400 B and other tray assemblies, as required. As an alternative, if loading is not a concern, a single tray assembly can be utilized.  
         [0037]    With respect to all of the embodiments discussed above, the tray inserts (partitions  20 ,  204 ,  304 ) and the spacers  414  are slidably disposed within the associated housing, and not necessarily rigidly fixed thereto. Advantageously, the slidable mounting not only eases manufacturing of the tray assemblies, but also permits easy removal of battery cells and re-configuration of the tray assemblies, if desired, so as to accommodate different size and/or number of battery cells. If some rigidity is required (e.g., to minimize vibration noise), the tray inserts may be fixed to portions of the housing.  
         [0038]    The tray inserts, spacers, and housings are also formed of any suitable material (e.g., metal) which is acceptable for use in motive-power applications, particularly to satisfy explosion-proof and spark-proof requirements such as those set forth by the Underwriters Laboratories (UL-583).  
         [0039]    With further reference to all of the embodiments discussed above, a front cover FC may be mounted to housing H (housing H is equivalent to the housings  12 ,  202 ,  302  and  402 ) as shown in FIG. 10. In addition, a back cover BC may be provided so that the housing H can include a full enclosure with an opening for receiving the battery cells—that opening being covered by the front cover FC. With reference to FIG. 11, a tray insert (e.g., tray insert  204 ) is mounted into the housing H behind the front cover FC. Open compartments (such as open compartment  206 B) may be defined in the housing H by any of the tray inserts such as by leaving a space or spaces between the tray insert and the side wall of the housing H. With any of the compartments (open or otherwise), battery cells can be stacked vertically and/or horizontally (preferably, horizontally).  
         [0040]    A battery charger B may also be disposed within the housing H or attached thereto. Preferably, the battery charger B is mounted via panel opening PO into an additional enclosed space located behind the back cover BC of the housing H. With panel P closing the panel opening PO, the battery charger B is filly enclosed. In addition, apertures may be formed in the housing H so as to give access to the battery cells (e.g., apertures A in the front cover FC to give access to the battery terminals). The battery charger B may be mounted into an enclosed space above the tray insert and battery cells (as shown in FIG. 4B). The battery cells may be connected in series or in parallel and cables are electrically connected to the battery cells suitable for connecting to a motive device requiring power.  
         [0041]    The entire housing H is mountable to a motive-powered vehicle to supply power thereto. With reference to U.S. Pat. No. 5,441,123, particularly FIGS. 11-13 and the associated description thereof, the housing H is mountable to Class 1-3 vehicles. The entire disclosure of U.S. Pat. No. 5,441,123 is incorporated by reference herein.  
         [0042]    Various changes and modifications can be made to the present invention. It is intended that all such changes and modifications come within the scope of the invention as set forth in the following claims.