Abstract:
A battery pack is described. One embodiment of the battery pack includes a pair of end frames, the end frames having a top and a bottom and a pair of sides, the end frames having a detent on at least one of the sides of the end frames to receive a clamp; a frame positioned between the pair of end frames, the frame having a top and a bottom and a pair of sides, the frame having a ridge on at least one of the sides of the frame; a plurality of battery cells positioned in the frame and the pair of end frames, the plurality of battery cells electrically connected to each other at the top of the frame; and at least one cooling fin positioned between the battery cells. Methods of repairing battery packs are also described.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to battery packs and more particularly to battery packs having a modular design. 
         [0002]    Currently, the battery cells in some battery packs are positioned in frames which are used to house the cells, cooling fins, and, in some cases, expansion material, such as foam sheets. The frames can also be used as a conduit for liquid cooling of the cells. However, the frames are not designed with features to assist with repairing the module. In some battery packs, cell tabs are welded to a separate interconnect board. Once the battery cells are welded together, it is difficult to repair individual components in a section. If one component fails in a battery pack module fails, it is necessary to scrap the entire module. 
         [0003]    Therefore, there is a need for a battery pack module that is easier to repair and for methods of repairing battery pack modules. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention meets that need. One aspect of the invention involves a method of repairing a battery pack. In one embodiment, the method includes providing a battery pack comprising: a pair of end frames, the end frames having a top and a bottom and a pair of sides, the end frames having a detent on at least one of the sides of the end frames to receive a clamp; a frame positioned between the pair of end frames, the frame having a top and a bottom and a pair of sides, the frame having a ridge on at least one of the sides of the frame; a plurality of battery cells positioned in the frame and the pair of end frames, the plurality of battery cells electrically connected to each other at the top of the frames; and at least one cooling fin positioned in the frame and the pair of end frames between the plurality of battery cells; inserting a clamp into the detents in the end frames to maintain compression on the battery pack; transferring the battery pack with the clamp in the detents to a repair station, the ridge supporting the battery pack during the transfer; removing the clamp to permit access to the bottom of the frame; and repairing at least one of the battery cells, cooling fins, frames, or end frames while maintaining the electrical connection. 
         [0005]    Another aspect of the invention relates to a battery pack. One embodiment of the battery pack includes a pair of end frames, the end frames having a top and a bottom and a pair of sides, the end frames having a detent on at least one of the sides of the end frames to receive a clamp; a frame positioned between the pair of end frames, the frame having a top and a bottom and a pair of sides, the frame having a ridge on at least one of the sides of the frame; a plurality of battery cells positioned in the frame and the pair of end frames, the plurality of battery cells electrically connected to each other at the top of the frame; and at least one cooling fin positioned between the battery cells. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of one embodiment of a battery pack module of the present invention. 
           [0007]      FIG. 2  is a side view of the battery pack module of  FIG. 1 . 
           [0008]      FIG. 3  is an illustration of one embodiment of a frame. 
           [0009]      FIG. 4  is an illustration of one embodiment of a cooling fin. 
           [0010]      FIGS. 5A-C  illustrate embodiments of different shapes for the ridge on the side of the frame. 
           [0011]      FIG. 6  is an illustration of a battery pack module inverted in a cradle for servicing. 
           [0012]      FIG. 7  is a perspective view of one embodiment of an electrical connection for the battery pack module. 
           [0013]      FIG. 8  is an illustration of a portion of a battery pack module spread apart with a frame spreader tool with attached fin guides. 
           [0014]      FIG. 9  is an illustration of a pusher tool for inserting a cooling fin into the battery pack module. 
           [0015]      FIG. 10  is an illustration of a seal replacement tool. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    The battery pack module includes a number of design features that aid in the disassembly and repair of battery pack modules. The end frames can include detents that allow clamps to be used to maintain module compression during transfer of the battery pack module to the repair station. The sides of the frame(s) and/or end frames can include a ridge that provides a lifting surface for transporting the battery pack module, as well as providing an interface with the repair cradle. The module can be spread apart at the bottom edge to allow for repair or replacement of various parts, including, but not limited to, cooling fins, coolant manifold seals, end caps, and the center manifold. The module can include modular electrical integration. In addition, there can be section-specific components which allow the modules to be easily separated. These features allow the modules to repaired, reducing the waste of parts which are still usable. 
         [0017]    As shown in  FIGS. 1-5 , the battery pack module  100  includes a pair of end frames  105 ,  110 , with a series of frames  115  between them. There are cooling fins  120  in the frames. The frames  115  and end frames  105 ,  110  have tops  140 , bottoms  145 , and sides  150 ,  155 . During use, adjacent battery pack modules can be held together by tie rods (not shown) to form a section. The tie rods are removed after the clamps have been attached as described below. 
         [0018]    The end frames  105 ,  110  have detents  125  for receiving a clamp  130 . The detents are placed near the lower end  145  of the frames and end frames. For example, as shown in  FIGS. 1-2 , there are two pairs of detents, one pair above the seal and one pair below the seal. This arrangement helps to maintain seal compression during transport. However, there could be one or more pairs, as desired. A retention feature (such as a projection) on each end of the clamp  130  fits into the detents  125  on each end frame. The clamp maintains compression on the battery pack module when it is outside the battery pack for repair. Suitable clamps include, but are not limited to turnbuckle clamps, and over-center clamps. 
         [0019]    The frames  115  and/or end frames  105 ,  110  have one or more ridges  160  on one or both sides  150 ,  155 . The ridges  160  provide a surface on which to support the battery pack module while it is being transported. The battery pack module can be placed in a cradle  190  for repair. The cradle  190  can include a rod or bar or the like  195  which fits under the ridge  160 . The ridge  160  can be designed to support the rod or bar (or other shape)  195  in the cradle  190 . For example, the ridge could be a triangle, or a rectangle with a edge parallel to the top (e.g., as shown in  FIG. 5A ). Alternatively, it could have an edge which is slighted inclined (e.g., as shown in  FIG. 5B ) so that it will force the bar toward the battery pack making it more difficult for the battery pack module to slip out of the cradle. Another possibility is that the ridge has a notch (e.g., as shown in  FIG. 5C ) that will interlock with the rod or bar on the cradle. Other shapes for the ridge will be known to those of skill in the art. It is not required that all of the frames include a ridge. However, a sufficient number of frames should include ridges so that the battery pack module has adequate support. 
         [0020]    In some embodiments, the battery pack module will be placed in the cradle  190  with the upper end  140 , the end having the electrical connection, on top. In order to work on the module, the cradle with the battery pack module in it will be inverted so that the lower end  145  can be accessed. In this the orientation, the ridge  160  can be used support a bar or rod for the cradle. Alternatively, there could be another ridge or a clip  200  for this purpose. 
         [0021]    In some embodiments, the cooling fin  120  can include coolant channels  180 . The coolant channels  180  will be in fluid communication with a coolant manifold which supplies coolant to the cooling fin  120 . The end frames  105 ,  110  and frames  115  can include a coolant manifold  165 . The frames can include a groove  170  into which a seal  175  is placed to seal the coolant manifold. 
         [0022]    A series of modules (A, B, C) including the boards for the electrical connections is shown in  FIG. 6 . The boards contain electrical buss bars and sensors which are connected to the module. 
         [0023]    After the battery pack module has been transported to the repair station for repair, it is positioned so that the individual performing the repair has access to the lower end of the battery pack module (typically by inverting the module). The electric connection on the upper end of the battery pack module is maintained during the repair process so that separation of the frames at the upper end is limited or prevented. When the clamp(s) is removed, the lower end of the battery pack module becomes loose, allowing some movement and separation at the lower end of the frames and end frames. This allows access to the components within the battery pack module for repair. For example, the cooling fin can be removed and replaced, or the seal for the cooling manifold can be removed and replaced. The seal can include a tag, which is an extension of the seal, and it is positioned in the frame. The tag can be gripped with needle-nose pliers, for example, and removed without having to open the module so far that there is a risk of damage to the module. 
         [0024]      FIGS. 8-10  illustrate a variety of tools which can be used in servicing the battery pack module. A frame spreader tool  205  can be used to help separate the frames. It is positioned on the inverted cradle and opens the bottom of the module to provide space between the frames for access to the seals and fins during the repair process. Fin guides  210  can be inserted into the battery pack module between frames to protect the surfaces of the battery cells during cooling fin removal and installation. The fin guides  210  can hang on the rails of the frame spreader tool  205 . A pusher tool  215  helps to insert a new cooling fin  220  with minimal required clearance into a module that has been welded. It can include a stop feature  225  that interfaces with the frame spreader  205  to keep the cooling fin from going in too far and making contact with the battery cell terminals causing a short. A seal replacement tool  230  aligns the seal with the grooves in the frame while keeping the operators hands at a safe distance to enable simple installation of a new seal. 
         [0025]    The battery pack module can include other components, if desired. Not all of the additional components are required for each module. Therefore, the additional components are designed to be separate from the module so that they can be included as needed. This provides additional versatility. 
         [0026]    It is noted that terms like “preferably,” “commonly,” and “typically” are not utilized herein to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present invention. 
         [0027]    For the purposes of describing and defining the present invention it is noted that the term “device” is utilized herein to represent a combination of components and individual components, regardless of whether the components are combined with other components. For example, a “device” according to the present invention may comprise an electrochemical conversion assembly or fuel cell, a vehicle incorporating an electrochemical conversion assembly according to the present invention, etc. 
         [0028]    For the purposes of describing and defining the present invention it is noted that the term “substantially” is utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The term “substantially” is also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue. 
         [0029]    Having described the invention in detail and by reference to specific embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. More specifically, although some aspects of the present invention are identified herein as preferred or particularly advantageous, it is contemplated that the present invention is not necessarily limited to these preferred aspects of the invention.