Patent Publication Number: US-2020303709-A1

Title: Battery and method for producing a battery

Description:
BACKGROUND OF THE INVENTION 
     The invention is based on a battery. The present invention also provides a method for producing such a battery. 
     It is known from the prior art that batteries used as drive batteries in hybrid, plug-in hybrid and electric vehicles, such as, in particular, lithium-ion batteries, are of a modular structure, i.e. are composed of a plurality of battery modules. Furthermore, a battery module preferably has a multiplicity of individual battery cells that are interconnected to form the battery module, the individual battery cells being able to be interconnected in series or in parallel. The voltage taps of the individual battery cells such as, in particular, lithium-ion battery cells, lithium-polymer battery cells or lead acid accumulators, in this case are electrically connected to each other by means of so-called cell connectors. The cell connectors in this case are attached to the voltage taps of the individual battery cells via screwed, welded or riveted connections. Furthermore, the battery modules of the battery are also electrically connected to each other in series and/or in parallel by means of connecting elements, termed module connectors, that are attached by a screwed, welded or riveted connection. A plurality of battery modules form so-called sub-units of the battery, which share, for example, a common cooling means. A battery is usually constructed from at least two sub-units. 
     In the construction of a battery, special contact protection measures are required in the case of voltages of 60 volts d.c. and above, such that only trained electricians are permitted to perform work on the battery in the case of such voltages. 
     Known from the prior art, from DE 10 2012 215 205 A1, is a cell connector that interconnects two battery cells of differing battery modules. 
     Furthermore, known from DE 10 2012 215 495 is a series connection having a battery cell for adjusting a characteristic quantity of the battery cell. 
     SUMMARY OF THE INVENTION 
     The battery, and the method for producing such a battery, having the characterizing features of the invention, have the advantage that two battery modules of a battery can be electrically connected to each other in a simple and reliable manner by a plug-in connection. It is thereby possible, in particular, to reduce the extent of work during production, since it is possible to dispense with the welded, riveted or screwed connections known from the prior art. 
     According to the invention, a battery having at least two battery modules is provided. A battery module in this case comprises, respectively, a plurality of battery cells that are interconnected electrically in series and/or in parallel. The battery cells in this case are, in particular, lithium-ion battery cells. In addition, a battery module has a positive voltage tap and a negative voltage tap. In this case, a first module connecting element is connected in an electrically conductive manner to the positive voltage tap, and/or a second module connecting element is connected in an electrically conductive manner to the negative voltage tap. A module connecting element of a first battery module and a module connecting element of a second battery module are connected in an electrically conductive manner. The electrically conductive connection of the module connecting elements in this case is realized as a plug-in connection. 
     The measures stated in the dependent claims render possible advantageous developments and improvements of the device specified in the independent claim or of the method specified in the independent claim. 
     It is expedient if the module connecting elements are directly connected to each other in an electrically conductive manner. It is thereby possible, during the construction of the battery, to arrange the first battery module and the second battery module at their position inside the battery and, by realizing the plug-in connection, to connect the module connecting element of the first battery module and the module connecting element of the second battery module to each other in an electrically conductive manner, with the result that no further production steps are subsequently needed in order to realize the electrically conductive connection. 
     It is furthermore also expedient if a further electrically conductive connecting element connects the module connecting elements to each other in an electrically conductive manner. It is thereby possible, during the construction of the battery, to arrange the first battery module and the second battery module at their position inside the battery, without in this case realizing an electrically conductive connection between the battery modules. A battery composed of a plurality of battery modules can therefore be constructed without the battery modules in this case already being electrically interconnected in series and/or in parallel, and thus there is no occurrence of elevated voltages that are above the voltages of the individual battery modules, such that there is no need for special contact protection measures if the voltage of a battery module is below the permissible voltage of 60 volts d.c. After the mechanical construction of the battery has been completed by the arrangement of the individual battery modules, building-up of the voltage can be effected. This is to be understood to mean that the individual battery modules are connected to each other in an electrically conductive manner. In particular, it is to be understood to mean that a module connecting element of the first battery module and a module connecting element of the second battery module are connected are connected to each other in an electrically conductive manner, wherein a further electrically conductive connecting element connects the module connecting elements to each other in an electrically conductive manner. 
     According to one embodiment of the invention, for the purpose of interconnecting the first battery module and the second battery module in series, the first module connecting element of the first battery module and the second module connecting element of the second battery module are connected in an electrically conductive manner. Furthermore, according to the one embodiment of the invention, for the purpose of interconnecting the first battery module and the second battery module in series, the second module connecting element of the first battery module and the first module connecting element of the second battery module may also be connected in an electrically conductive manner. As a result, a positive voltage tap and a negative voltage tap, or a negative voltage tap and positive voltage tap, are connected in an electrically conductive manner, such that a serial interconnection of the battery modules is realized. 
     According to another embodiment of the invention, for the purpose of interconnecting the first battery module and the second battery module in parallel, the first module connecting element of the first battery module and the first module connecting element of the second battery module are connected in an electrically conductive manner. Furthermore, according to the other embodiment of the invention, for the purpose of interconnecting the first battery module and the second battery module in parallel, the second module connecting element of the first battery module and the second module connecting element of the second battery module may also be connected in an electrically conductive manner. As a result, a positive voltage tap is connected in an electrically conductive manner to a positive voltage tap, or a negative voltage tap is connected in an electrically conductive manner to a negative voltage tap, such that a parallel interconnection of the battery modules is realized. 
     In particular, a battery module in each case has substantially two end faces, two side faces, one battery-module underside and one battery-module upper side. The two end faces are arranged opposite each other, and preferably parallel to each other. Furthermore, the two side faces are arranged opposite each other, and preferably parallel to each other. The battery-module underside and the battery-module upper side are arranged opposite each other, and preferably parallel to each other. In particular, one of the two end faces and one of the two side faces are arranged at right angles in relation to each other. Furthermore, in particular, one of the two end faces and the battery-module underside or the battery-module upper side are arranged at right angles in relation to each other. In particular, one of the two side faces and the battery-module underside or the battery-module upper side are arranged at right angles in relation to each other. The positive voltage tap and/or the negative voltage tap of the battery module are/is preferably arranged on the battery-module upper side. Furthermore, the cell connectors that electrically connect the plurality of battery cells to each other in series and/or in parallel are also arranged on the battery-module upper side. It is expedient in this case if the first module connecting element and/or the second module connecting element are/is arranged on the battery-module underside, on one of the two end faces or on one of the two side faces. It is thereby possible for a module connecting element not to be arranged on the battery-module upper side, on which the cell connectors for series and/or parallel interconnection of the individual battery cells are usually also arranged, such that safety can be increased in construction of the battery. Furthermore, as described in the following, it is thereby possible to improve the accessibility of the module connecting elements. 
     It is advantageous if the first battery module and the second battery module are arranged next to each other, one of the two end faces of the first battery module being arranged directly adjacently to one of the two end faces of the second battery module, and in addition the first module connecting element and/or the second module connecting element being arranged on a side face. It is thereby possible to arrange the first battery module and the second battery module inside a battery, having a plurality of battery modules, in which the plurality of battery modules are also arranged, for example, in a plurality of planes over one another, without already interconnecting the battery modules when they are being arranged. In this case, the final interconnection of the battery modules, and thus the building-up of the voltage, can be effected by means of the further electrically conductive connecting element only after the arrangement of the battery modules, since the module connecting elements are still arranged in an accessible manner even after the mechanical construction of the battery. Battery modules arranged in a plurality of planes over one another, is to be understood here to means that the battery-module upper side of at least one battery module and the battery-module underside of another battery module are arranged directly adjacently to each other. Clearly, it is also possible, if the first battery module and the second battery module are arranged next to each other, one of the two end faces of the first battery module being arranged directly adjacently to one of the two end faces of the second battery module, to attach the first module connecting element and/or the second module connecting element also to the battery-module underside or to the battery-module upper side, should the plurality of battery modules of the battery be arranged in the same plane, and a side face of one battery module thus also be arranged directly adjacently to a side face of another battery module. 
     In addition it is advantageous if the first battery module and the second battery module are arranged next to each other, one of the two side faces of the first battery module being arranged directly adjacently one of the two side faces of the second battery module, and furthermore the first module connecting element and/or the second module connecting element being arranged on an end face. It is thereby possible, in the case of a battery in which battery modules, such as have just been described, are arranged, for example, in a plurality of planes over each other, and two battery modules, in particular, are each arranged with one of the two side faces directly adjacent to each other, that the building-up of the voltage can be performed only after the mechanical construction of the battery, since the module connecting elements are still accessible. Furthermore, in this case it is also conceivable, in the case of the battery modules being arranged in a plane, for the first module connecting element and/or the second module connecting element to be attached to the battery-module upper side or to the battery-module underside, since the module connecting elements are still accessible, even after the mechanical construction of the battery. 
     Furthermore, it is also advantageous if the first battery module and the second battery module are arranged next to each other, the battery-module upper side of the first battery module being arranged directly adjacently to the battery-module underside of the second battery module, and in addition the first module connecting element and/or the second module connecting element being arranged on one of the two end faces or on one of the two side faces. It is thereby possible to arrange the first battery module and the second battery module in mutually superimposed planes of a battery having a plurality of battery modules, and to connect them in an electrically conductive manner only after the mechanical arrangement of the battery modules. In particular, the electrically conductive connection may be realized as a plug-in connection of the first module connecting element and of the second module connecting element, by means of the further electrically conductive connecting element. 
     Owing to the advantageous possibilities that have just been described, for arranging the first module connecting element and/or the second module connecting element on one of the two end faces, on one of the two side faces or on the battery-module underside, or in particular also on the battery-module upper side, a battery having a plurality of battery modules can be provided in a simple and safe manner. The plurality of battery modules in this case can be arranged over one another in a plurality of planes, and a plurality of battery modules can also be arranged in each plane. It is preferred in this case to first arrange the battery modules at their position inside the battery, and thus to realize the overall mechanical construction of the battery, and then in a subsequent step to realize the electrically conductive connections for the purpose of connecting the individual battery modules in series and/or in parallel. Since the first module connecting element and/or the second module connecting element can be arranged on one of the two end faces, on one of the two side faces or on the battery-module underside, or in particular also on the battery-module upper side, it is possible to arrange the module connecting element such that it is still accessible even after the overall mechanical construction of the battery has been effected. The electrical interconnection in this case can then be realized by the further electrically conductive connecting element. In particular, in the case of battery modules in which the total voltage is less than, for example, 60 volts d.c., only the final step, of building-up the voltage by realizing the electrically conductive connections between the individual battery modules, needs to be performed by a trained electrician having appropriate safety knowledge. 
     Expediently, a module connecting element in each case comprises a housing composed of an electrically insulating material. The positive voltage tap and the negative voltage tap of the battery module can thereby be electrically insulated, making it possible to avoid unwanted short circuits or electrical contacting. Furthermore, a module connecting element comprises an electrically conductive connecting portion that is arranged in the electrically insulating housing. The connecting portion is additionally connected in an electrically conductive manner to the positive or the negative voltage tap of the respective battery module. In this case, for the purpose of connecting the first battery module and the second battery module in an electrically conductive manner, a first connecting portion of the module connecting element of the first battery module and a second connecting portion of the module connecting element of the second battery module are connected to each other in an electrically conductive manner. The connection of the first connecting portion and the second connecting portion in this case is realized as a plug-in connection. In this case, for the purpose of direct electrically conductive connection, the first connecting portion may have an opening, in which the second connecting portion, realized as a plug-in element, is arranged. In addition, in this case the first connecting portion may have an opening, and the second connecting portion may have an opening that extends continuously through the housing of the module connecting element having the second connecting portion, the further electrically conductive connective element additionally being arranged such that it extends in the opening of the first connecting element and in the opening of the second connecting element. Since the second connecting portion has an opening through the housing of the module connecting element having the second connecting portion, the further electrically conductive connecting element can still connect the first connecting portion and the second connecting portion to each other in an electrically conductive manner, even after the first battery module and the second battery module have been arranged next to each other. 
     It is advantageous if the module connecting element is connected to the respective battery module in a materially bonded or form-fitting manner. In particular, in this case this connection may be realized as a welded, riveted or bonded connection. In addition, it is also possible for the module connecting element to be latched-in on the battery module. In particular, the housing can absorb the joining forces. 
     The invention additionally relates to a method for producing a battery described above. All advantages and development possibilities mentioned in connection with the battery according to the invention are also furthermore intended in this case to be applicable in connection with the method according to the invention, such that reciprocal reference may be made between the battery and the method for producing the battery. 
     In a method step a), a plurality of battery cells are electrically interconnected in series and/or in parallel to form a first battery module and to form a second battery module. The first battery module and the second battery module, each having a plurality of battery cells interconnected in series and/or in parallel, are thus thereby provided. In a method step b), a first module connecting element, connected to the positive voltage tap in an electrically conductive manner, and/or a second module connecting element, connected to the negative voltage tap in an electrically conductive manner, are/is arranged on the first battery module and on the second battery module. As a result, the first battery module has at least one first module connecting element or one second module connecting element, and the second battery module has at least one first module connecting element or one second module connecting element, that are in each case connected to the positive or negative voltage tap of the battery module. In a method step c), an electrically conductive connection is realized between the module connecting element of the first battery module and the module connecting element of the second battery module. The electrically conductive connection of the module connecting elements in this case is realized as a plug-in connection. This enables the first battery module and the second battery module to be interconnected to each other in series and/or in parallel in a simple manner. 
     Furthermore, it is advantageous if the first battery module and the second battery module are arranged next to each other. In this case, in particular, the module connecting element of the first battery module and the module connecting element of the second battery module are not connected to each other in an electrically conductive manner. It is only in a subsequent method step d) that the module connecting elements are connected to each other in an electrically conductive manner via the further electrically conductive connecting element. This has the advantage, as has already been described in connection with the battery according to the invention, that the overall mechanical construction of a battery, having a plurality of battery modules, can be effected first, and the electrically conductive connections between the individual battery modules can be effected in a subsequent step, for the purpose of building-up the voltage. 
     In particular, the invention relates to a method in which, in method step a), a plurality of battery modules, having a plurality of battery cells that are electrically interconnected in series and/or in parallel, is additionally provided. In method step b) in this case, a first module connecting element, connected in an electrically conductive manner to the positive voltage tap, and/or a second module connecting element, connected in an electrically conductive manner to the negative voltage tap, are/is also to be arranged, respectively, on the plurality of battery modules. Furthermore, in method step c), the battery modules are first arranged next to each other to form the battery. In the method step d), respectively two module connecting elements of adjacently arranged battery modules are then connected to each other in an electrically conductive manner by respectively one further electrically conductive connecting element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention are represented in the drawings and explained in greater detail in the description that follows. 
       There are shown 
         FIG. 1 a    an embodiment of a battery module having a first arrangement of a module connecting element, 
         FIG. 1 b    an embodiment of a battery module having a second arrangement of a module connecting element, 
         FIG. 1 c    an embodiment of a battery module having a third arrangement of a module connecting element, 
         FIG. 2  a schematic top view of a battery according to the invention, 
         FIG. 3 a    an embodiment of a plug-in connection for realizing a direct electrically conductive connection between two module connecting elements, and 
         FIG. 3 b    an embodiment of a plug-in connection for realizing an electrically conductive connection between two module connecting elements by means of a further electrically conductive connecting element. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 a  to 1 c    each show embodiments of a battery module  1  having a plurality of battery cells  2 , arranged next to each other, which are preferably identical. The battery cells  2  each have a positive voltage tap  3  and a negative voltage tap  4 . For the purpose of interconnecting the individual battery cells  2  in series, as shown in  FIGS. 1 a  to 1 c   , a positive voltage tap  3  of a battery cell  2  and a negative voltage tap  4  of an adjacent battery cell  2  are connected to each other in an electrically conductive manner. This electrically conductive connection may be effected by means of cell connectors  16  known from the prior art. 
     In the case of the serial interconnection of the battery cells  2 , the positive voltage tap  3  of a first battery cell  21  and the negative voltage tap  4  of a last battery cell  22  is not connected, for example by means of a cell connector  16 , to an adjacent battery cell  2  of the same battery module  1 . The first battery cell  21  and the last battery cell  22  refers, respectively, to one of the two outer of the battery cells  2  of the battery module  1  that are arranged next to each other, as is also intended to be illustrated by  FIG. 2 . 
     The positive voltage tap  3  of the first battery cell  21  simultaneously forms the positive voltage tap  5  of the battery module  1 , and the negative voltage tap  4  of the last battery cell  22  simultaneously forms the negative voltage tap  6  of the battery module  1 . 
     As can be seen from  FIGS. 1 a  to 1 c   , the battery module  1  additionally has a first module connecting element  7 , and a second module connecting element  8  that is not shown in  FIGS. 1 a  to 1 c   . The positive voltage tap  6  of the battery module  1  is connected in an electrically conductive manner to the first module connecting element  7 . The negative voltage tap  6  of the battery module  1  is connected in an electrically conductive manner to the second module connecting element  8 . 
     The first module connecting element  7  and the second module connecting element  8  each have a housing  9 , of an electrically insulating material. Furthermore, a module connecting element  7 ,  8  comprises an electrically conductive connecting portion  10 , described in greater detail below with reference to  FIGS. 3 a    and  3   b.    
     For the purpose of realizing an electrically conductive connection between a first battery module  101  and a second battery module  102 , a first connecting portion  11  of the module connecting element  7 ,  8  of the first battery module  101  and a second connecting portion  12  of the module connecting element  7 ,  8  of the second battery module  102  are connected to each other in an electrically conductive manner. 
     The battery module  1  has substantially two mutually opposite side faces  13 , two mutually opposite end faces  14 , a battery-module upper side  151  and, opposite the battery-module upper side  151 , a battery-module underside  152 . 
     As has already been described, the first module connecting element  7  and/or the second module connecting element  8  may be arranged on one of the two side faces  13 , on one of the two end faces  14 , or on the battery-module upper side  151 , and in particular also on the battery-module underside  152 , to enable the required spatial arrangement of the battery modules  1  to be effected. 
     The embodiment of a battery module  1  shown in  FIG. 1 a    is advantageous, for example, if the battery module  1  is arranged with a side face  13  adjacent to a side face  13  of another battery module  1 , wherein the first module connecting element  7  is arranged on the battery-module upper side  151  and wherein, for example, a further element of the battery that is not shown here is to be arranged on the side face  14  adjacent to the first module connecting element  7 , such that there is no space available here. Furthermore, in such a case, if the battery module  1  is arranged with a side face  13  adjacent to a side face  13  of another battery module  1 , with no space being available on the battery-module upper side  151 , for example because of the arrangement of a further battery module  1 , the first module connecting element  7  can also be arranged on an end face  14 , as shown in  FIG. 1   b.    
     The embodiment shown in  FIG. 1 c    is advantageous if the battery module  1  is arranged with an end face  14  adjacent to an end face  14  of another battery module  1 . In this case, the first module connecting element  7  is arranged on a side face  13 . In addition, in such a case the module connecting element  7  can also be arranged on the battery-module upper side  151  or the battery-module underside  152 , which is not shown here. 
     As can be seen in  FIGS. 1 a  to 1 c   , the connecting portion  10  of the first module connecting element  7  is realized as an opening  111  that, in particular, may also be realized so as to extend continuously through the housing  9  of the first module connecting element  7 , as explained in greater detail in the following. 
       FIG. 2  shows a schematic top view of a battery  100  according to the invention. 
     The battery  100  has a first battery module  101  and a second battery module  102  which, as already described in  FIGS. 1 a  to 1 c   , each have a plurality of battery cells  2 . 
     The battery cells  2  of the first battery module  101  and the battery cells  2  of the second battery module  102  are each electrically connected to each other in series by means of cell connectors  16 . In this case, a positive voltage tap  3  of a battery cell  2  is connected in an electrically conductive manner to a negative voltage tap  4  of an adjacent battery cell  2 . It is also conceivable for the battery cells  2  to be electrically connected to each other in parallel. Furthermore, the positive voltage tap  3  of the first battery cell  21  of the first battery module  101  is not connected in an electrically conductive manner to the voltage tap  3 ,  4  of an adjacent battery cell  2  of the first battery module  101 , and thus forms the positive voltage tap  5  of the first battery module  101 . The negative voltage tap  4  of the last battery cell  22  of the first battery module  101  is not connected in an electrically conductive manner to the voltage tap  3 ,  4  of an adjacent battery cell  2  of the first battery module  101 , and thus forms the negative voltage tap  6  of the first battery module  102 . Furthermore, the negative voltage tap  4  of the last battery cell  22  of the second battery module  102  is not connected in an electrically conductive manner to the voltage tap  3 ,  4  of an adjacent battery cell  2  of the second battery module  102 , and thus forms the negative voltage tap  6  of the second battery module  102 . The positive voltage tap  3  of the first battery cell  21  of the second battery module is not connected in an electrically conductive manner to the voltage tap  3 ,  4  of an adjacent battery cell  2  of the second battery module  102 , and thus forms the positive voltage tap  5  of the second battery module  102 . 
     It can additionally be seen from  FIG. 2  that the first module connecting element  7  is connected in an electrically conductive manner to the positive voltage tap  5  of the first battery module  101 , and the second module connecting element  8  is connected in an electrically conductive manner to the negative voltage tap  6  of the second battery module  102 . 
     The first battery module  101  is arranged with a first end face  141  adjacent to a second end face  142  of the second battery module  102 . The first module connecting element  7  and the second module connecting element  8  are each respectively arranged on a side face  13  of the first battery module  101  and of the second battery module  102 . In this case the first module connecting element  7  and the second module connecting element  8  are connected to each other in an electrically conductive manner, the electrically conductive connection of the module connecting elements  7 ,  8  being realized as a plug-in connection. 
       FIGS. 3 a  and 3 b    each show, in schematic form, embodiments of an electrically conductive connection, realized as a plug-in connection, of the first module connecting element  7  and second module connecting element  8 , according to the section A-A shown in  FIG. 2 . 
       FIG. 3 a    shows a first embodiment, in which the module connecting elements  7 ,  8  are directly connected to each other in an electrically conductive manner. In this case, the first module connecting element  7  and the second module connecting element  8  each have a housing  9  of an electrically insulating material. The first module connecting element  7  additionally comprises a first connecting portion  11 , which is composed of an electrically conductive material and in addition is connected in an electrically conductive manner to the positive voltage tap  5  of the first battery module  101 . As shown by  FIG. 3 a   , the first connecting portion  11  comprises an opening  111 . The second module connecting element  8  comprises a second connecting portion  12 , which is composed of an electrically conductive material and in addition is connected in an electrically conductive manner to the negative voltage tap  6  of the second battery module  102 . As shown by  FIG. 3 a   , the second connecting portion  12  comprises a projection  112 , which projects out of the housing  9  and serves as a plug-in element. For the purpose of realizing an electrically conductive connection between the first connecting portion  11  and the second connecting portion  12 , the projection  112  is inserted into the opening  111  in such a manner that an electrically conductive connection is realized as a result of contacting between the first connecting portion  11  and the second connecting portion  12 . 
       FIG. 3 b    shows a second embodiment, in which a further electrically conductive connecting element  20  connects the module connecting elements  7 ,  8  to each other in an electrically conductive manner. In this case, the first module connecting element  7  and the second module connecting element  8  each have a housing  9  of an electrically insulating material. The first module connecting element  7  additionally comprises the first connecting portion  11 , which is composed of an electrically conductive material and in addition is connected in an electrically conductive manner to the positive voltage tap  5  of the first battery module  101 . As shown by  FIG. 3 b   , the first connecting portion  11  comprises an opening  111 . The second module connecting element  8  additionally comprises the second connecting portion  12 , which is composed of an electrically conductive material and in addition is connected in an electrically conductive manner to the negative voltage tap  6  of the second battery module  102 . As shown by  FIG. 3 b   , the second connecting portion  12  comprises an opening  113  that extends continuously through the housing  9  of the second module connecting element  8 . The further electrically conductive connecting element  20  connects the first connecting portion  11  and the second connecting portion  12  in an electrically conductive manner. The further electrically conductive connecting element  20  in this case is arranged in the opening  111  of the first connecting portion  11  and in the opening  113  of the second connecting portion  12 . The realization of the second connecting portion  12  as an opening  113  extending continuously through the housing  9  has the advantage, in particular, that the first battery module  101  and the second battery module  102  can be arranged next to each other without realizing an electrically conductive connection between the first connecting portion  11  and the second connecting portion  12 . The electrically conductive connection can then be realized in a further step, since the further electrically conductive connecting element  20  can be inserted in the shown direction  21 . In addition, it is clearly possible for the first connecting portion  11  also to be realized as an opening extending continuously through the housing  9  of the first connecting element  7 , such that insertion contrary to the shown direction  21  is also possible. 
     In order, in the case of the first battery module  101  being arranged next to the second battery module  102 , to prevent an electrically conductive connection from being realized between the first connecting portion  11  and the second connecting portion  12  before the further electrically conductive connecting element  20  is inserted, an insulation element  21 , which serves to effect electrical insulation and prevents unwanted contacting, may be arranged between the first module connecting element  7  and the second module connecting element  8 .