Abstract:
To provide a method for producing an electrically conductive bond between an electrical line, which includes a plurality of individual conductors, and an electrically conductive component, including producing from a crimp element blank a crimp element enclosing portions of the individual conductors, the crimp element including a continuous side and a discontinuous side, at which edge regions of the crimp element lie opposite one another, and substance-to-substance bonding of the crimp element with a contact surface of the component, which is simple to carry out and nevertheless always results in a robust substance-to-substance bond between the crimp element and the component, it is proposed that the crimp element be produced in such a way that the continuous side of the crimp element includes two bearing surfaces which are spaced from one another, at which the crimp element is substance-to-substance bondable to the contact surface of the component.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of international application number PCT/EP2014/051244, filed on Jan. 22, 2014, which claims priority to German patent number 10 2013 201 167.9, filed on Jan. 24, 2013, the entire specification of both being incorporated herein by reference. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The present invention relates to a method for producing an electrically conductive bond between an electrical line, which comprises a plurality of individual conductors, and an electrically conductive component, the method comprising the following method steps:
       producing from a crimp element blank a crimp element enclosing portions of the individual conductors, the crimp element comprising a continuous side and a discontinuous side, at which edge regions of the crimp element lie opposite one another; and   substance-to-substance bonding of the crimp element at the continuous side thereof or at the discontinuous side thereof with a contact surface of the component.       
 
       BACKGROUND 
       [0005]    In known methods of this type, the crimp element is formed in the form of a “B-crimp”, which has a substantially B-shaped cross-section. On its continuous side, such a B-crimp has a substantially planar bearing surface, while on the discontinuous side of the B-crimp two curved bearing surfaces spaced from one another in the transverse direction of the crimp element by a recess located between them are formed on crests of the crimp element remote from the continuous side of the crimp element. 
         [0006]    Such a B-crimp may be applied, during substance-to-substance bonding of the crimp element to the component, in two different orientations onto a contact surface of the component, namely with the continuous side facing the component or with the discontinuous side facing the component. 
         [0007]    If the continuous side of the B-crimp faces the component, the crimp element is substance-to-substance bonded, for example welded, along the entire planar bearing surface of the continuous side thereof to the contact surface of the component. 
         [0008]    If the B-crimp faces the component with its discontinuous side, the crimp element is substance-to-substance bonded, in particular welded, to the component at two contact zones, in particular weld zones, which are spaced from one another on the bearing surfaces which are spaced from one another. 
         [0009]    The peel forces, i.e., the shear forces, needed to detach the crimp element from the component are very different in these two alternative orientations of the crimp element relative to the component, specifically the peel forces are markedly higher if the crimp element faces the component with its discontinuous side than in the orientation in which the crimp element rests with its continuous side against the component. 
         [0010]    The reason for this in particular resides in the greater localization of the energy input into the contact zones between the crimp element and the component during substance-to-substance bonding (in particular during welding) and in the greater localization of the shear forces acting on the contact zones between the crimp element and the component if the contact zones are smaller. 
         [0011]    To achieve higher peel forces and thus a more robust substance-to-substance bond between the crimp element and the component, the crimp element must thus always be applied to the component in the orientation in which the discontinuous side of the crimp element faces the component. 
       SUMMARY OF THE INVENTION 
       [0012]    It is an object of the present invention to provide a method for producing an electrically conductive bond between an electrical line and an electrically conductive component of the above-stated type, which method is simple to carry out and nevertheless always results in a robust, substance-to-substance bond between the crimp element and the component. 
         [0013]    This object is achieved according to the invention in a method having the features of the pre-characterizing clause of claim  1  in that the crimp element is produced in such a way that the continuous side of the crimp element comprises two bearing surfaces spaced from one another, at which the crimp element is substance-to-substance bondable to the contact surface of the component. 
         [0014]    The concept underlying the present invention is thus that of configuring the geometry of the crimp element in such a way that the peel forces are sufficiently high even if the crimp element is applied with its continuous side against the component. 
         [0015]    Because the crimp element with the geometry according to the invention can be used on both sides, this crimp element and the method carried out therewith to produce an electrically conductive bond between an electrical line and an electrically conductive component is particularly easy to assemble and fault-tolerant. 
         [0016]    The crimp element used according to the invention may in particular have a cross-section which resembles the number 8. 
         [0017]    In one particular configuration of the method according to the invention, provision is made for a recess to be produced on the continuous side of the crimp element. 
         [0018]    Such a recess may in particular be produced by impressing. 
         [0019]    Such impressing may proceed for example using a die provided in a crimping tool, which die is preferably substantially complementary in form to the recess. A method for producing a crimp element from a crimp element blank using a crimping tool is described for example in DE 10 2010 035 424 A1, to which reference is made in this respect and which is incorporated by reference into this description. 
         [0020]    In a preferred configuration of the invention, provision is made for the recess to extend from a front edge of the crimp element as far as a rear edge of the crimp element. 
         [0021]    In the method according to the invention, the crimp element preferably takes the form of a (modified) B-crimp, which has a discontinuous side and a continuous side, a recess preferably being formed on the continuous side of the B-crimp. 
         [0022]    The crimp element may in principle be formed from any electrically conductive, workable material. 
         [0023]    Preferably, the crimp element blank contains a metallic material, for example copper or a copper alloy, and preferably is formed substantially completely from a metallic material, in particular from copper or a copper alloy. 
         [0024]    Substance-to-substance bonding of the crimp element with the component preferably proceeds by a welding process, in particular by an ultrasonic welding process. 
         [0025]    In a preferred configuration of the method according to the invention, the component is formed as a cell connector for electrically conductively bonding cell terminals of electrochemical cells of an electrochemical device. 
         [0026]    The electrically conductive bond between the electrical line and such a cell connector may in particular serve to transfer the electrical potential prevailing at the connection point of the cell connector via the electrical line to a monitoring device of the electrochemical device. 
         [0027]    Alternatively or in addition, the method according to the invention may be used to produce an electrically conductive bond between a temperature sensor and a monitoring device of the electrochemical device. 
         [0028]    Thus, as a result of the electrically conductive bond, it may in particular be possible to carry out individual cell monitoring of the electrochemical cells of an electrochemical device with regard to temperature and/or voltage. 
         [0029]    The present invention further relates to an assembly, which comprises an electrical line, which comprises a plurality of individual conductors, a crimp element enclosing portions of the individual conductors and having a continuous side and a discontinuous side, at which edge regions of the crimp element lie opposite one another, and an electrically conductive component substance-to-substance bonded to the crimp element. 
         [0030]    A further object of the present invention is to configure such an assembly such that it is simple to assemble and nevertheless always has a robust substance-to-substance bond between the crimp element and the component. 
         [0031]    This object is achieved according to the invention in an assembly having the features of the pre-characterizing clause of claim  10  in that the continuous side of the crimp element comprises two bearing surfaces which are spaced from one another, at which the crimp element is substance-to-substance bonded with a contact surface of the component. 
         [0032]    This particular geometry of the crimp element ensures that the peel forces of the bond between the crimp element and the component are sufficient even if the crimp element is applied with its continuous side against the component. 
         [0033]    claims  11  to  15  relate to particular configurations of the assembly according to the invention, the features and advantages of which have already been explained above in connection with particular configurations of the method according to the invention. 
         [0034]    By means of the method according to the invention, the stranded wires or individual conductors of an electrical line can be precompacted by enclosing portions of the individual conductors with a crimp element and the crimp element can be substance-to-substance bonded, in particular welded, with an electrically conductive component. 
         [0035]    The particular geometry of the crimp element makes it possible to use the crimp element on both sides, so resulting in more uniform peel forces, which are preferably substantially independent of the orientation of the crimp element relative to the component. 
         [0036]    Further features and advantages of the invention constitute the subject matter of the following description and of the graphical representation of an exemplary embodiment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]      FIG. 1  is a schematic perspective representation of an end region of an electrical line, which comprises a plurality of individual conductors, which have been enclosed by a crimp element in the form of a B-crimp; 
           [0038]      FIGS. 2 and 3  are schematic perspective representations which illustrate the production of a crimp element from a crimp element blank at end portions of the individual conductors of the electrical line; 
           [0039]      FIG. 4  shows a schematic section through an assembly comprising an electrical line with a plurality of individual conductors, a crimp element in the form of a B-crimp enclosing end portions of the individual conductors and a component welded to a continuous side of the crimp element; 
           [0040]      FIG. 5  shows a schematic section through an alternative embodiment of the assembly of  FIG. 4 , in which the component is welded to a discontinuous side of the crimp element; 
           [0041]      FIG. 6  is a schematic perspective representation of an end portion of an electrical line, which comprises a plurality of individual conductors, and a crimp element enclosing portions of the individual conductors, the continuous side of which crimp element comprises two bearing surfaces which are spaced from one another, at which the crimp element is substance-to-substance bondable to a contact surface of a component; 
           [0042]      FIG. 7  shows a schematic section through an assembly, which comprises the electrical line and the crimp element of  FIG. 6  and a component welded to the crimp element on the discontinuous side thereof; and 
           [0043]      FIG. 8  shows a schematic section through an alternative embodiment of the assembly of  FIG. 7 , in which the component is welded to the crimp element on the continuous side thereof. 
       
    
    
       [0044]    Identical or functionally equivalent elements are provided with the same reference signs in all the figures. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0045]    An assembly according to the prior art illustrated in  FIGS. 1 to 5  and designated overall as  100  comprises an electrical line  102  in the form of a cable  104  which comprises a plurality of stranded wires or individual conductors  106  and an electrically insulating covering  108 , a crimp element  110  in the form of a B-crimp  112 , which encloses end portions of the individual conductors  106 , and a component  114  of an electrically conductive material (see in particular  FIGS. 1 ,  4  and  5 ). 
         [0046]    The crimp element  110  has been produced from a crimp element blank  116  illustrated in  FIG. 2  in that, using a crimping tool (not shown), mutually opposing edge regions  118   a ,  118   b  are bent around the end portions  120 , not provided with the covering  108 , of the individual conductors  106  and pressed against the individual conductors  106  in such a way as to result in the crimp element  110  with the substantially B-shaped cross-section illustrated in  FIGS. 1 ,  4  and  5 . 
         [0047]    During production of the crimp element  110 , the end portions  120 , enclosed by the crimp element  110 , of the individual conductors  106  are compacted and pressed together in force-locking manner. 
         [0048]    The resultant crimp element  110  comprises a continuous side  122  with an unbroken, substantially planar bearing surface  124  and a side opposite the continuous side  122 , hereinafter designated discontinuous side  126 , at which the curved edge regions  118   a  and  118   b  of the crimp element  110  lie opposite one another. 
         [0049]    Provision is preferably made for the edge regions  118   a  and  118   b  to end at a short spacing from one another or to touch one another. 
         [0050]    The crests of the edge regions  118   a  and  118   b  remote from the continuous side  122  of the crimp element  110  form two bearing surfaces  128   a  and  128   b  respectively of the discontinuous side  126  of the crimp element  110 , which are spaced from one another in a transverse direction  130  of the crimp element  110  by an intermediate recess  132 . 
         [0051]    The base of the recess  132  is formed for example by the free edges  134   a  and  134   b  of the edge regions  118   a  or  118   b  respectively of the crimp element  110 . 
         [0052]    The transverse direction  130  of the crimp element  110  is oriented perpendicular to a longitudinal direction  136  of the crimp element  110 , which direction extends substantially parallel to the longitudinal direction of the electrical line and substantially parallel to the free edges  134   a  and  134   b  of the crimp element  110 . 
         [0053]    The lateral free edges  134  of the crimp element  110  join a front edge  138  to a rear edge  140  of the crimp element  110 . 
         [0054]    For substance-to-substance bonding of the crimp element  110  to the component  114 , the crimp element  110  may be applied in two different orientations to a contact surface  142  of the component  114 , namely with the continuous side  122  facing the component  114 , as shown in  FIG. 4 , or with the discontinuous side  126  facing the component  114 , as shown in  FIG. 5 . In the case of the orientation illustrated in  FIG. 4 , the crimp element  110  is welded, for example by an ultrasonic welding process, along the entire planar bearing surface  124  of the continuous side  122 , forming a weld zone  144 . 
         [0055]    In the case of the alternative orientation shown in  FIG. 5 , the crimp element  110  is welded, for example by an ultrasonic welding process, at the bearing surfaces  128   a  and  128   b  which are spaced from one another, forming two weld zones  146   a  and  146   b  which are spaced from one another in the transverse direction  130 . 
         [0056]    In the two alternative embodiments of the substance-to-substance bond according to  FIGS. 4 and 5 , the peel forces, i.e., the shear forces, needed to detach the crimp element  110  from the component  114  are very different, specifically the peel forces in the variant embodiment illustrated in  FIG. 5 , in which the crimp element  110  faces the component  114  with its discontinuous side  126 , are markedly higher than in the variant embodiment illustrated in  FIG. 4 , in which the crimp element  110  rests with its continuous side  122  against the component  114 . 
         [0057]    The reason for this in particular resides in the greater localization of the energy input into the weld zones  146   a ,  146   b  between the crimp element  110  and the component  114  during substance-to-substance bonding and in the greater localization of the shear forces acting on the weld zones  146   a ,  146   b  in the orientation of the crimp element  110  relative to the component  114  shown in  FIG. 5 . 
         [0058]    Since higher peel forces mean a more robust and durable bond between the crimp element  110  and the component  114 , the crimp element  110  must therefore be applied to the component  114  in the orientation illustrated in  FIG. 5  in order to achieve higher peel forces and thus a more robust substance-to-substance bond between the crimp element  110  and the component  114 . 
         [0059]    In the assembly  100  formed according to the invention and illustrated in  FIGS. 6 to 8  of an electrical line  102  with individual conductors  106 , a crimp element  110  and a component  114 , the peel forces are on the contrary always substantially of equal magnitude, irrespective of whether the crimp element  110  is applied with its discontinuous side  126  against the component  114 , as illustrated in  FIG. 7 , or with its continuous side  122 , as illustrated in  FIG. 8 . 
         [0060]    This is achieved in that the crimp element  110  is produced in such a way that the continuous side  122  of the crimp element  110  also comprises two bearing surfaces  148   a  and  148   b  which are spaced from one another, at which the crimp element  110  is substance-to-substance bondable with the contact surface  142  of component  114 , wherein the bearing surfaces  148   a  and  148   b  are separated from one another in the transverse direction  130  of the crimp element  110  by a recess  150  arranged therebetween. 
         [0061]    The recess  150  preferably extends from the front edge  138  of the crimp element  110  as far as to the rear edge  140  thereof. 
         [0062]    The recess  150  is preferably produced during the crimping process, i.e., during production of the crimp element  110  from the crimp element blank  116 , for example by impressing. 
         [0063]    Impressing may proceed for example using a die provided in a crimping tool, which die is preferably substantially complementary in form to the recess  150 . 
         [0064]    The crimp element  110  preferably has substantially the same radius of curvature in the region of the bearing surfaces  148   a  and  148   b  of the continuous side  122  of the crimp element  110  as at the bearing surfaces  128   a  and  128   b  respectively of the discontinuous side  126  of the crimp element  110 . 
         [0065]    It is particularly favorable for the crimp element  110  to be substantially mirror-symmetrical with regard to the bearing surfaces  148   a ,  148   b  of the continuous side  122  of the crimp element  110  and the bearing surfaces  128   a ,  128   b  of the discontinuous side  126  of the crimp element  110  relative to a longitudinal central plane  152  of the crimp element  110  oriented parallel with the transverse direction  130  and parallel with the longitudinal direction  136  of the crimp element  110  and/or substantially rotationally symmetrical with regard to rotation of the crimp element  110  by 180° about a longitudinal center axis  154  of the crimp element  110  extending parallel to the longitudinal direction  136 . 
         [0066]    In this way it is ensured that the crimp element  110  is substance-to-substance bonded to the component  114 , for example by an ultrasonic welding process, at two weld zones  156   a  and  156   b  spaced from one another in the transverse direction  130  of the crimp element  110  even if said crimp element is applied with its continuous side  122  against the component  114 . 
         [0067]    The weld zones  156   a  and  156   b  which bring about the substance-to-substance bond between the crimp element  110  and the component  114  when the crimp element  110  is applied with its continuous side  122  against the component  114  thus have substantially the same geometry as the weld zones  146   a  and  146   b  which bring about the substance-to-substance bond between the crimp element  110  and the component  114  when the crimp element  110  is applied with its discontinuous side  126  against the component  114 , as illustrated in  FIG. 7 . 
         [0068]    When using the crimp element  110  according to the invention, the peel forces are thus of substantially equal magnitude irrespective of the position of the crimp element  110  relative to the component  114  such that, when bonding the crimp element  110  to the component  114 , it is not necessary to note whether the crimp element  110  is applied with the discontinuous side  126  or with the continuous side  122  against the component  114 . 
         [0069]    Assembly work is thereby significantly simplified. 
         [0070]    In contrast with the substantially B-shaped crimp element  110  according to the prior art, as illustrated in  FIGS. 1 to 5 , the crimp element  110  according to the invention illustrated in  FIGS. 6 to 8  has a cross-section which resembles the number 8. 
         [0071]    Apart from the additional impressing of the recess  150  on the continuous side  122  of the crimp element  110 , production of the crimp element  110  corresponds to the production process according to the prior art as explained above with reference to  FIGS. 1 to 5 . 
         [0072]    A material which may be considered for the crimp element blank  116  is in principle any electrically conductive, workable material. 
         [0073]    Preferably, the crimp element blank  116  is formed from a metallic material, for example from copper or a copper alloy. 
         [0074]    The individual conductors  106  of the electrical line  102  may in principle also be formed from any material that has sufficient electrical conductivity. 
         [0075]    The individual conductors  106  may in particular be formed from copper or a copper alloy. 
         [0076]    Component  114  may in principle be formed from any material that has sufficient electrical conductivity. 
         [0077]    Component  114  is preferably a constituent of a cell contacting system, with which cell terminals of electrochemical cells of an electrochemical device are bonded together. 
         [0078]    Provision may in particular be made for component  114  to be a cell connector  156  which serves to electrically conductively bond cell terminals of various electrochemical cells of an electrochemical device. 
         [0079]    Such a cell connector  156  is preferably formed from an electrically conductive metallic material, for example from copper or a copper alloy or from aluminum or an aluminum alloy. 
         [0080]    The electrically conductive bond between the electrical line  102  and such a cell connector  156  may in particular serve to transfer the electrical potential prevailing at the connection point of the cell connector  156  via the electrical line  102  to a monitoring device of the electrochemical device. 
         [0081]    An assembly  100  according to the invention of the above-described type may furthermore be used to produce an electrically conductive bond between a temperature sensor and a monitoring device of the electrochemical device.