Abstract:
A method for insulating a battery module ( 100 ) which has a multiplicity of battery cells ( 10 ), having at least one foldable insulation element ( 20 ), having at least the following steps: 
     a) forming a receptacle pocket ( 21 ) from the insulation element ( 20 ) for receiving at least one battery cell ( 10 ), 
     b) closing the receptacle pocket ( 21 ) by means of attachment sections ( 22 ) which are arranged laterally on the insulation element ( 20 ), as a result of which the battery cell ( 10 ) is surrounded at least on five sides by the insulation element ( 20 ), as a result of which the individual battery cell ( 10 ) is insulated with respect to an adjacent battery cell ( 10 ).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a method for insulating a battery module, and to a battery module. 
         [0002]    Battery modules are usually composed of a multiplicity of battery cells which are connected in series or in parallel to form a battery module. What are referred to as hard case cells have a metallic housing, wherein in order to provide galvanic insulation the battery housing is usually connected to a battery terminal (anode), so that corrosion of the battery housing of the hard case cell can be essentially avoided. Owing to the connection of the metallic hard case cell to the one electrode, it is not possible to handle the battery cell or the battery module without safety precautions, making it necessary to insulate the hard case cell, at least electrically, with insulation means. Conventionally, protective surface coatings are applied to the hard case cell for this, wherein each individual cell has to be provided with the surface coating in order therefore to ensure electrical insulation with respect to a user, among other things. This type of insulation must satisfy at the same time the requirements during the operation of the battery cell, wherein large temperature fluctuations and, in particular, resistance to heat are necessary. 
       SUMMARY OF THE INVENTION 
       [0003]    The method according to the invention for insulating a battery module which has a multiplicity of battery cells, having at least one foldable insulation element, has at least the following steps:
       a) forming a receptacle pocket from the insulation element for receiving at least one battery cell,   b) closing the receptacle pocket by means of attachment sections which are arranged laterally on the insulation element, as a result of which the battery cell is surrounded at least on five sides by the insulation element, as a result of which the individual battery cell is insulated with respect to an adjacent battery cell.       
 
         [0006]    Further features and details of the invention can be found in the claims, the description and the drawings. In this context, features and details which have been described in relation to the method according to the invention also apply, of course, in relation to the battery module according to the invention, and vice versa, with the result that with respect to the disclosure reference always is, or always can be, made reciprocally to the individual aspects of the invention. 
         [0007]    The method according to the invention therefore permits a multiplicity of battery cells to be insulated from one another individually—that is to say separately—and in a simple way, permitting reliable (in particular electrical) insulation of the battery cell on at least five sides with respect to an adjacent battery cell and/or a user. The foldable insulation element is configured here in such a way that in order to form the receptacle pocket from the insulation element, the latter can be adapted by folding, at least in certain sections along the outer contour of the battery cell, in particular of the hard case cell. In this context, there may be provision according to the invention that the insulation element has, at least in certain sections, impressions and/or preshaped folding contours along which the insulation element can be folded along the outer contour of the battery cell. However, a battery cell is not absolutely necessary to form the receptacle pocket from the insulation element. Accordingly, the receptacle pocket can be produced without a battery cell. In a further method step, the receptacle pocket can be closed by means of attachment sections which are arranged laterally on the insulation element, with the result that the receptacle pocket or receptacle compartment which is formed surrounds the battery cell on at least five sides (in particular completely enclosed) by the insulation element. In this context, the receptacle pocket which is formed has essentially the geometry of the battery cell, with the result that the insulation element essentially completely surrounds the battery cell on at least five sides. Closing the receptacle pocket increases the stability of the (correctly shaped/folded) insulation element with the result that the receptacle pocket which is formed preferably does not collapse into itself, in particular as long as there is no battery cell contained in it, but instead is embodied in a dimensionally stable fashion. As a result, it is possible to cause the battery cell to be accommodated easily in the receptacle pocket without the receptacle pocket having to be additionally secured. Generic battery modules are usually composed of a multiplicity of battery cells which are connected in series or in parallel, with the result that the method is preferably repeated until at least all the battery cells are surrounded by the insulation element. 
         [0008]    The insulation element is advantageously an endless film, wherein in a step a′) at least a first battery cell is positioned on the insulation element. The endless film is preferably wound onto a reel, with the result that the insulation element can be easily unrolled in step a′). The step a′) is correspondingly carried out before the step a), wherein after the unrolling of the insulation element at least a first battery cell is positioned on the insulation element, in particular along a prefabricated impression or folding edge. The insulation element is in this context configured in a flexible way such that it can be wound as an endless film onto a reel and correspondingly can be wound onto the reel and/or unwound therefrom, preferably in an automated fashion. According to the invention, the insulation element in the form of an endless film is consequently unrolled, in particular unwound from the reel, at least to such an extent that the unrolled section of the insulation element is dimensioned in such a way that the receptacle pocket can be formed from the section, with the result that the battery cell is surrounded by the insulation element on at least five sides. It is also conceivable that the unrolled, in particular the unwound, section of the insulation element is dimensioned in such a way that after the formation of the receptacle pocket there is sufficient insulation element present, with the result that the insulation element also surrounds the battery cell on the sixth side thereof. This ensures that the battery cell is at least essentially insulated on all sides from the insulation element. 
         [0009]    In a step a″) the insulation element can advantageously be folded at least along the standing face edges of the battery cell, in particular the insulation element is formed by folding along an edge orthogonal in a double layer between at least two battery cells. The term standing face edges is to be understood within the scope of the invention as meaning those edges of the battery cell with which the battery cell is positioned on the insulation element and along which the insulation element is folded in such a way that after the folding the insulation element surrounds the battery cell on at least five sides. Correspondingly, the standing face edges of the battery cell are formed by the edges of the longitudinal side and the broad side of the battery. Consequently, after the positioning of the battery cell on the insulation element, a first side, the standing face of the battery cell, is covered by the insulation element. If the folding of the insulation element along the standing face edges is then carried out in the opposite direction to the standing face, it is ensured that the insulation element surrounds the battery cell on at least four further sides of the battery cell. Correspondingly, the battery cell is arranged on the standing face and on the adjoining side faces of the battery cell or of the battery cell housing. Furthermore, it is conceivable that the insulation element is dimensioned in such a way that, in addition to the previous five faces (1 standing face and 4 side faces) of the battery cell, the insulation element is at least partially or even completely surrounded the last face (cover), which lies opposite the standing face of the battery cell, by the insulation element. In this context, the insulation element can be folded along the edges of the face lying opposite the standing face of the battery cell. This face which lies opposite the standing face is referred to below as the cover of the battery cell. Furthermore, the terminal poles of the battery cell can be arranged on the cover. Within the scope of the invention, said terminal poles can also be at least partially surrounded by the insulation element, wherein, in particular, cutouts can be provided in the cover face (cover) of the insulation element. 
         [0010]    The attachment sections in step b) can advantageously be bonded, welded and/or sewn at least in certain sections. In this context it is conceivable that the attachment sections are arranged along the broad sides and/or the longitudinal sides of the battery cell. The attachment sections are preferably located along the broad side of the battery cell. According to the invention, the attachment sections are preferably embodied in one piece, in particular with uniform material, with the insulation element. In this context, the attachment sections can have bonding agent, with the result that bonding faces, along which the insulation element can be bonded, are present on the attachment sections. Furthermore, it is conceivable that a bonding agent is subsequently applied to the attachment sections, with the result that it is possible to bond the attachment sections and therefore the insulation element. It is also conceivable that the attachment sections of the insulation element are welded, wherein by inputting thermal energy into the material of the insulation element or of the attachment sections the attachment sections and the insulation element can be thermally bonded to one another, as a result of which a frictionally locking and positively locking connection is achieved at least on certain parts of the attachment sections. Furthermore, it is conceivable that the attachment sections are sewn. Within the scope of the invention, the term attachment sections is to be understood as referring to a part of the insulation element which is embodied in such a way that the attachment sections have, on the longitudinal side or the broad side of the battery cell, a hem line and/or an overlap as a result of the folding. Along the hem line, at least two attachment sections of the insulation element can be bonded and/or welded to one another. If at least two attachment sections overlap on the longitudinal side or the broad side of the battery cell, these overlapping attachment sections can be bonded, welded and/or sewn. 
         [0011]    According to a further aspect of the invention, a battery module is claimed, wherein the battery module has a multiplicity of battery cells which are insulated from one another by means of an insulating element, wherein the insulation is manufactured in accordance with a method according to the invention. Therefore, the battery module in accordance with the invention provides the same advantages as have been described in detail with respect to the method according to the invention. 
         [0012]    It is conceivable according to the invention that the insulation element has a plastic, in particular a fiber-reinforced plastic, which is embodied, in particular, in a transparent or translucent fashion, at least in certain sections, wherein, in particular, the insulation element material has cutouts, as a result of which the geometry of the insulation element can be adapted to the geometry of the battery cell. Furthermore, it is conceivable that the insulation element and/or the attachment sections have, at least in certain sections, material reinforcements and/or are embodied in a watertight fashion. An insulation element which is embodied in a transparent or translucent fashion is advantageous, since changes to the battery cell and damage or escaping of the electrolyte can be detected from the outside without damaging the insulation element or having to remove the battery cell from the insulation element. Furthermore, it is advantageous if the insulation element has material cutouts. Material cutouts can be here e.g. cutouts for the terminal poles of the battery cell. Furthermore, material cutouts can be a punched shape of the insulation element, wherein, in particular, the attachment sections are formed from the insulation element by means of a punching method. It is thereby ensured that the insulation element and/or the attachment sections are shaped in such a way that they are adapted to the geometry of the battery cell, with the result that by folding the insulation element and/or the attachment sections along the edges of the battery cell, said edges are preferably completely surrounded by the insulation element. Furthermore, it is possible to obtain the advantage that by means of a punched-out insulation element and the resulting material cutouts it is possible to essentially avoid the formation of folds or an excessively large amount of surplus material, which is undesired and can unnecessarily increase material costs. Inventive material reinforcements of the insulation element can improve the mechanical loadability of the insulation element, with the result that during transportation and/or in the case of a force effect from the outside (for example sharp or blunt objects) can be essentially avoided by the material reinforcement. It is particularly preferred if the insulation element is embodied in a watertight fashion, with the result that it is essentially possible to prevent the electrolyte from escaping and a fluid from entering from the outside into the insulation element, and in particular into the receptacle pocket which is formed. 
         [0013]    Furthermore, it is conceivable that the insulation element is cut into a suitable shape, in particular, by means of a laser. Correspondingly, the film can be cut in accordance with a cutting pattern and by means of a cutting process, e.g. a laser, and thereby adapted. 
         [0014]    Within the scope of the invention it is conceivable that at least one receptacle element for receiving a transportation means is arranged on the insulation element, in particular on the attachment sections. The receptacle elements can be embodied here, for example, in the form of a clip on the insulation element, with the result that the insulation element, in particular the folded insulation element which is embodied with the receptacle pockets, can preferably be transported using a transportation means after being filled with battery cells. In this context, the transportation means can be, for example, a robot arm or similar aids which are suitable for transporting a battery module. The receptacle element can preferably have reinforcements here, with the result that, when the battery module is transported and as a result of mechanically occurring forces, damage to the insulation element can be prevented owing to the reinforcements. 
         [0015]    According to the invention, it is also conceivable that the insulation element is a shrink-fit film, as a result of which positive engagement with the at least one battery cell can be achieved. If the insulation element is embodied as a shrink-fit film, the shrink-fit film which is preferably manufactured from plastic is shrunk to a large extent under the effect of heat, in particular hot air. This brings about positive engagement of the film or of the insulation element with the at least one battery cell, with the result that said battery cell is electrically insulated from the surroundings and protected against mechanical damage. 
         [0016]    A thermocouple can advantageously be arranged on the insulation element, wherein the temperature of the battery cell can be controlled by means of the thermocouple. The thermocouple can be a component which is designed to conduct thermal energy, with the result that heat can be directed away from or toward the battery cell. Correspondingly, the battery cell or the battery cells can be cooled or heated by means of the thermocouple. This has the advantage that the battery cells can be kept at the operating temperature, with the result that it is possible to avoid both overheating and an excessively low operating temperature of the battery cells, and therefore to limit the efficiency of the battery cells. 
         [0017]    The insulation element can advantageously have a thickness between approximately 50 μm and approximately 1000 μm, preferably between approximately 100 μm and approximately 700 μm, particularly preferably between approximately 200 μm and approximately 400 μm. The thinner the material of the insulation element, the easier it is to fold the insulation element or adapt it to the shape of the battery cell. A relatively large thickness of the insulation element is, on the other hand, better electrical insulation properties and the protection against mechanical force effects with the result that both the battery cell and a user of the battery cell are better protected by a relatively thick insulation element. Furthermore, a relatively thin insulation element can be manufactured more cost-effectively, with the result that the manufacturing costs for the insulation element, and therefore of the battery module, can be reduced with insulation according to the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Further measures which improve the invention can be found in the following description of a number of exemplary embodiments of the invention which are illustrated schematically in the figures. All of the features and/or advantages which arise from the claims, the description or the drawings, including structural details, spatial arrangements and method steps, can be essential to the invention both per se and in a wide variety of combinations. It is to be noted here that the figures only have a descriptive character and are not intended to limit the invention in any way. In the following figures, identical reference symbols are used for the same technical features, even of different exemplary embodiments. In the drawings, in a schematic form: 
           [0019]      FIG. 1  shows an unrolled insulation element according to the invention in a first method step, 
           [0020]      FIG. 2  shows the insulation element according to the invention in a second method step, 
           [0021]      FIG. 3  shows a battery module according to the invention, and 
           [0022]      FIG. 4  shows a receptacle pocket, manufactured according to the inventive method, from the insulation element. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]      FIG. 1  shows the insulation element  20  in an unrolled state, wherein a multiplicity of battery cells  10  are arranged spaced apart from one another on the insulation element  20 . The battery cells  10  are arranged here on the insulation element  20 , in the regions at which the attachment sections  22  are located. The insulation element  20  is embodied in  FIG. 1  as a punched or laser-cut film  20 , with the result that the attachment sections  22  extend over the dimension of the battery cells  10 . Accordingly, the attachment sections  22  form wing-like sections on the insulation element  20 . In the left-hand region of  FIG. 1 , a first battery cell  10  is arranged on the insulation element  20 , in the region of the attachment sections  22 . The battery cell  10  is arranged here essentially centrally between the attachment sections  22  on the insulation element  20 . The insulation element  20  has in total ten attachment sections  22  in  FIG. 1 , wherein in each case two attachment sections  22  respectively extend in the region of a battery cell  10 , on both sides in the region of the broad side BS of the battery cells  10 . Furthermore,  FIG. 1  shows the edge orthogonal  24  which is arranged spaced apart between the first battery cell  10  and the second battery cell  10  which is spaced apart therefrom and is illustrated here by dashed lines. In a further method step, the insulation element  20  is folded along the edge orthogonal  24  in such a way that the insulation element  20  is embodied in a double layer between the first battery cell  10  and the second battery cell  10  which is indicated by dashed lines. On the third attachment section  22 , in  FIG. 1  a receptacle element  26  is arranged which is located in the form of a clip  26 , in each case on the outer edge of the attachment section  22 . If the attachment section  22  is then folded along the broad side BS of the battery cell  10 , the receptacle sections  26  form a possible way of lifting the battery cells  10  into the receptacle pockets  21  which are formed, and therefore of transporting said battery cells  10 . Furthermore, arranged on the insulation element  20  there is a thermocouple  27  which is arranged in such a way that the battery cell  10  can be arranged thereon, with the result that thermal conductivity can be brought about between the battery cell  10  and the thermocouple  27 . The thermocouple  27  preferably has the dimension of the battery cell  10  along the standing face of the battery cell  10 , which dimension is formed by the standing face edges  23  of the battery cell  10 . In addition to the material cutouts  25  between the attachment sections  22 , further material cutouts  25  are located on the insulation element  20 , at one end of the insulation element  20 . This end of the insulation element  20  is shown on the right-hand side in  FIG. 1 , wherein the material cutouts  25  in this region serve as a receptacle for the terminal poles of the battery cell  10 . Therefore, the section with the material cutouts  25  for the terminal poles for the battery cell  10  can be folded in a further method step in such a way that the pole terminals of the battery cells  10  extend through the material cutout  25 , with the result that, after the receptacle pockets  21  have been formed and the receptacle pockets  21  have been closed, only the pole terminals of the battery cells  10  extend out of the insulation element  20 . Correspondingly, the rest of the battery cells  10  are completely encased by the insulation element  20 . 
         [0024]      FIG. 2  shows the insulation element  20  according to the invention in a further method step. Here, in the upper region of the figure the insulation element  20  is illustrated in the left-hand region of  FIG. 2  as an unrolled insulation element  20 . 
         [0025]    The already unrolled part of the insulation element  20  which is located in the right-hand half of  FIG. 2  shows the completely formed receptacle pockets  21  with the battery cells  10  arranged therein. In the lower region of  FIG. 2 , the rolled-up insulation element  20  is shown in a plan view in the left-hand region, wherein the unrolled part of the insulation element  20  which extends therefrom has the same shape as in  FIG. 1 . In  FIG. 2 , two battery cells  10  are arranged on the already unrolled insulation element  20 . In this context, the battery cells  10  are arranged on the insulation element  20  in such a way that the attachment sections  22  extend on at least two sides of the battery cell broad side BS. The attachment sections  22  are therefore folded in a further method step along the broad side BS and therefore the first standing face edge  23 . However, the insulation element  20  is previously folded along the longitudinal side LS and therefore along the standing face edge  23  in such a way that the insulation element  20  extends along the longitudinal face which is located on the longitudinal side of the battery cells. In a further step the insulation element  20  is folded again along the edge orthogonal  24 , with the result that the insulation element  20  is formed in a double layer between the battery cells  10 . In the lower right-hand region of  FIG. 2 , the completely constructed receptacle pockets  21  are shown with the battery cells  10  arranged therein. In this context, adjacent to the battery cells  10  there are the attachment sections  22  which extend in a pyramid shape from the battery cell  10 . The attachment sections  22  which are therefore formed in a pyramid shape can be bonded, welded or sewn according to the invention. 
         [0026]      FIG. 3  shows a battery module  100  according to the invention having a total of three battery cells  10 , and the insulation element  20  which extends in each case in a double layer between the battery cells  10 . The receptacle pockets  21 , which are located between the insulation element  20  which is embodied in a double layer, are arranged in  FIG. 3 . In this context, it is apparent in  FIG. 3  that by folding the insulation element  20  along the edge orthogonal  24  the insulation element  20  is formed in a double layer before and/or between the battery cells  10 . The battery cells  10  are shown in  FIG. 3  from a side view, with the result that the face of the broad side BS of the battery cell  10  is shown. In the region of the battery cells  10  the attachment sections  22  are located on the insulation element  20 , wherein the attachment sections  22  are configured in such a way that the latter completely cover the illustrated face of the broad side BS of the battery cell  10  when the attachment section  22  is folded.  FIG. 3  also shows a thermocouple  27  which is located underneath the battery cell  10  which is arranged in the center in  FIG. 3 . According to the invention, it is also conceivable that the thermocouple  27  is located outside the insulation element  20 . In  FIG. 3  it is also apparent that the insulation element  20  is folded along the standing face edges  23  and along the edge orthogonals  24 . In this context, the insulation element  20  is firstly folded along the standing face edge  23  of the longitudinal side LS of the battery cell  10 , wherein in a subsequent step the insulation element  20  is folded again along the edge orthogonal  24 . According to this, it is conceivable according to the invention that the battery cell  10  is arranged on the subsequent insulation element section, with the result that folding is carried out again on the standing face edge  23  along the longitudinal side LS of the subsequent battery cell  10 . This process can be continued as desired, wherein according to the invention preferably five battery cells  10  are arranged on the insulation element  20 , with the result that a battery module  100  with a total of five battery cells  10  is formed. The attachment sections  22  are folded according to the invention along the standing face edge  23  on the broad side BS of the battery cell  10 . The attachment sections  22  can subsequently be welded, bonded or sewn to the insulation element  20  along the broad side face of the battery cell  10 . 
         [0027]      FIG. 4  shows the completely constructed receptacle pockets  21  in the insulation element  20 . In this context, the insulation element  20  has, in an upper region, in each case four receptacle elements  26  in the form of clips  26 . Furthermore, the insulation element  20  has, in the right-hand region of  FIG. 4 , a cover section which, after the receptacle pockets  21  have been filled with the battery cells  10 , can cover the latter.  FIG. 4  also shows the completely constructed and welded attachment sections  22  which are located along the face of the broad side BS of the battery cells  10 . Between the battery cells  10  on the receptacle pockets  21 , the edge orthogonals  24  are respectively shown between the battery cells  10 . 
         [0028]    Accordingly, the receptacle pockets  21  are separated from one another between the battery cells  10  by an insulation element  22  which is constructed in a double layer. Accordingly, the configuration which is constructed in a double layer results in reliable insulation of the battery cells  10  from one another. According to the invention, the cover region of the insulation element  20  can have material cutouts  25 , with the result that, in a closed state in which the cover region of the insulation element  20  is connected to the longitudinal or broad sides BS of the insulation element  20 , the cover region can be arranged in such a way that only the pole terminals of the battery cells  10  extend through the cover region of the insulation element  20 .