Abstract:
In a rechargeable battery having a plurality of rechargeable battery cells, wherein at least one rechargeable battery cell is connected to an electronic component, which is associated with the rechargeable battery, via an electrical line, the electrical line has at least one contact element which is electrically conductively connected to the at least one rechargeable battery cell by an electrically conductive adhesive.

Description:
This application is a National Stage Application of PCT/EP2009/056780, filed 3 Jun. 2009, which claims benefit of Ser. No. 10 2008 040 341.5, filed 11 Jul. 2008 in Germany and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
     STATE OF THE ART BACKGROUND 
     The present invention relates to a rechargeable battery with several rechargeable battery cells, at which at least one rechargeable battery cell is connected via an electrical line to an electronic component that is associated with the rechargeable battery. 
     Rechargeable batteries usually consist of several rechargeable battery cells, which are interconnected as packs or modules and which are connected with each other in an electrically conductive way via so-called cell connectors. The individual rechargeable battery cells are thereby usually welded together with the cell connectors, for example by electronic components. The cell connectors can be connected with electronic components via electrical lines, which are associated with the rechargeable batteries and which serve for example at Li-ion batteries not only for controlling and if necessary operating the state of charge of the rechargeable battery as a whole but moreover the state of charge of each individual rechargeable battery cell separately. 
     Rechargeable batteries are known from the state of the art, at which the cell connectors are already connected to such electrical lines before the welding with the rechargeable battery cells, for example by a joint, so that a corresponding cable harness can be prebuilt before the welding. Rechargeable batteries are also known, at which such electrical lines are connected to the cell connectors after the welding of the cell connectors with the rechargeable battery cells, for example by a joint or by means of suitable plug-in connectors. 
     The disadvantage of the state of the art is that the prebuilt cable harnesses are difficult and complicated to handle, because the electrical lines that are fixed at the cell connector can be disturbing during the welding process. Furthermore there is a risk that an undesired contacting of one or several cell connectors with one or several rechargeable battery cells causes a short circuit of individual rechargeable battery cells after the welding of one or several cell connectors. When soldering a joint after the welding there is the problem that an unintended damage of the rechargeable battery cells can occur by introducing a too big amount of heat during the soldering process, because in particular LI-ion cells are very sensitive to heat. At plug-in connectors on the other hand there is the problem that they are complex and cost-intensive to manufacture and require a relatively big space for making contact. Furthermore there is the problem with plug-in connectors, that dirt and corrosion can cause an insufficient contacting of the electrical line and therefore a bad electrical connection with the associated electronic component. 
     SUMMARY 
     One task of the invention is therefore to provide a new rechargeable battery with several rechargeable battery cells, at which a secure and stable connection of at least one rechargeable battery cell with an electronic component that is associated with the rechargeable battery via an electrical line is enabled, whereby the above described disadvantages of the state of the art are avoided. 
     This problem is solved by a rechargeable battery with several rechargeable battery cells, whereby at least one rechargeable battery cell is connected via an electrical line with an electronic component that is associated with the rechargeable battery. The electrical line provides at least one contact element, which is connected in an electrically conductive way to the at least one rechargeable battery cell via an electrically conductive adhesive. 
     According to an embodiment at least two rechargeable battery cells are connected with each other in an electrically conductive way via a cell connector. The cell connector is arranged between the at least one rechargeable battery cell and the contact element. The contact element is connected in an electrically conductive way with the cell connector via electrically conductive adhesive. 
     Therefore a secure, stable, inexpensive and space-saving connection between the contact element and the cell connector can be created due to the electrically conductive adhesive. 
     The electrical line and the contact element are preferably arranged on a carrier element. The carrier element is preferably a carrier foil, which can be fixed at at least two or several rechargeable battery cells for a fixation at the rechargeable battery, whereby the electrical line is construed as a flexible conductor path on the carrier foil. The flexible conductor path can implement the electronic component at least partially. 
     The invention allows therefore a pre-assembling of a suitable carrier foil, which can be fixed quickly and easily at the rechargeable battery, whereby stable and secure electrically conductive connections between the contact element and the rechargeable battery cells or cell connectors can be created due to the electrically conductive adhesive. The mounting can be simplified and a wrong contacting can be avoided thereby by a corresponding construction of the carrier foil. 
     According to one embodiment the contacting element is arranged on a fixing element, which can be fixed at at least two or several rechargeable battery cells for the fixation at the rechargeable battery. 
     Thus a wrong contacting can be avoided with simple means when mounting the electrical lines at the rechargeable battery. 
     The problem that has been mentioned at the beginning can also be solved by a contacting element, which can be fixed at an electrical line, which is construed in a rechargeable battery with several rechargeable battery cells for an electrically conductive connection of at least one rechargeable battery cell with an electronic component that is associated with the rechargeable battery. The contacting element can be connected in an electrically conductive way with the at least one rechargeable battery cell via an electrically conductive adhesive. 
     The problem that has been mentioned at the beginning is also solved by a carrier foil for a rechargeable battery with several rechargeable battery cells. The carrier foil can be fixed at least two of the several rechargeable battery cells for a fixation at the rechargeable battery and provides a flexible conductor path, which creates at least one electrical line with a contact element, whereby the contact element can be connected in an electrically conductive way with at least one rechargeable battery cell via an electrically conductive adhesive. 
     The problem that has been mentioned in the beginning is furthermore solved by an electronic machine tool with a rechargeable battery, which provides several rechargeable battery cells, whereby at least one rechargeable battery cell is connected to an electronic component that is associated with the rechargeable battery via an electrical line. The electrical line provides at least one contact element, which is connected to the at least one rechargeable battery cell in an electrically conductive way via an electrically conductive adhesive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is further explained in the subsequent description with the aid of an embodiment that is illustrated in the drawings. 
       It is shown in: 
         FIG. 1  a perspective illustration of an electronic machine tool with a rechargeable battery according to the invention, 
         FIG. 2  a perspective view of the rechargeable battery in  FIG. 1  with a contact element according to one embodiment, 
         FIG. 3  a perspective illustration of a carrier element according to an embodiment, 
         FIG. 4  a perspective view of the rechargeable battery in  FIG. 1  with the carrier element in  FIG. 3 , 
         FIG. 5  a perspective illustration of a cable harness according to an embodiment, and 
         FIG. 6  a perspective view of the rechargeable battery in  FIG. 1  with the cable harness in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an electronic machine tool  10  and a rechargeable battery  20  with a rechargeable battery housing  25 . The electronic machine tool  10  can be connected mechanically and electrically with the rechargeable battery via an interface  14  for a self-contained current supply. The rechargeable battery  20  is therefore inserted into the interface  14  in the direction of an arrow  15  and catches there, whereby automatically an electronic connection between the rechargeable battery  20  and the electronic machine tool  10  is created. 
     The machine tool  10  is construed exemplarily as cordless drilling screwdriver in  FIG. 1 . But is shall be pointed out that the present invention is not limited to cordless drill screwdrivers, but can be moreover applied to different cordless operated electronic machine tools, for example a drill hammer, an angle sander, a lawnmower etc. 
       FIG. 2  shows the rechargeable battery  20  in  FIG. 1 , which is illustrated without the rechargeable battery housing  25  for clarifying a first embodiment. The rechargeable battery  20  provides exemplarily ten rechargeable battery cells with cell headers  88  and opposite cell headers  87 , of which only the rechargeable battery cells  21 ,  22 ,  23 ,  24  are labeled for clarification purposes and for a clearness of the illustration. They are connected with each other in an electrically conductive way at their cell headers  88  via a cell connector  30 . 
     The cell connector  30  is connected via an electrical line  50  with an electronic component  40 , which is associated with the rechargeable battery  20  and which provides a protective circuit for the rechargeable battery  20  and/or connection elements for contacting the electronic machine tool  10  in  FIG. 1 . Therefore an end  68  of the line  50  is connected at the electronic component  40 . A contact element  55  is provided at its other end  51 , for example a metal plate, which is connected in an electrically conductive way with the cell connector  30  via an electrically conductive adhesive  60 . But it is pointed out that the contact element  55  can also be affixed directly on to one of the cell headers  88  of the rechargeable battery cells  21 ,  22 ,  23 ,  24 . 
     According to an embodiment the contact element  55  is self-adhesively coated with the electrically conductive adhesive  60 . The adhesive  60  preferably provides synthetic resin, for example light-activated epoxy resin and/or 2K-epoxy resin) 2-component epoxy resin). The synthetic resin is mixed with at least one electrically conductive component. The synthetic resin is preferable mixed with a percentage of silver powder, which is sufficiently high, in order for the adhesive  60  to provide an electrical conductivity, which is approximately equivalent to a well conducting metal, for example copper. 
     In order to interconnect the rechargeable battery cell of the rechargeable battery  20  application-specified to a pack or module, also other cells are connected with each other at their cell headers  87  or  88  in an electrically conductive way via corresponding cell connectors as it can be seen in  FIG. 2  and as it is indicated with a cell connector  39 . It is connected via an electrically conductive adhesive  63  in an electrically conductive way with a contact element  59 , which is fixed at the end of an electrical line  58 , which is connected with the electronic component  40  at its other end  69 . 
       FIG. 3  shows a carrier element  70 , on which the lines  50 ,  58  are construed with the assigned contact elements  55  or  59 . The carrier element  70  is preferable a pre-assembled carrier foil  75 , on which the lines  50 ,  58  and contact elements  55 ,  59  are construed as a flexible conductor path  80 . According to an embodiment the flexible conductor path  80  also implements the electronic component  40  at least partially. But  FIG. 3  shows one embodiment of the carrier foil  75 , in which the ends  68 ,  69  of the lines  50  or  58  stick out of the carrier foil  75  for contacting a separately construed electronic component  40 , as described in  FIG. 4 . 
     As it can be seen in  FIG. 3  the carrier foil  75  exemplarily provides a middle part  79  and two side parts  71 ,  72 , which can be folded on top of each other at associated folding lines  73 ,  74  for mounting on the rechargeable battery cells  21 ,  22 ,  23 ,  24 . For a fixation at the rechargeable battery  20  at least the side parts  71 ,  72  can each be fixed at at least two of the rechargeable battery cells  21 ,  22 ,  23 ,  24 , preferable at their cell headers  87 , or  88 , for example with the aid of an non-conducting adhesive connection. Alternatively only the contact elements  55 ,  59  can also be construed self-adhesive as described above. 
     In order to clarify a second embodiment  FIG. 4  shows the rechargeable battery  20  in  FIG. 1  without the rechargeable battery housing  25 , at which the carrier element  70  in  FIG. 3  construed as carrier foil  75  is fixed. Therefore its side parts  71 ,  72  are preferable affixed on to the cell headers  87  or  88  via suitable adhesive connections. The contact elements  55 ,  59  contact thereby the cell connectors  30 ,  39  in an electrically conductive way via provided electrically conductive adhesives  60  or  63  and the ends  68 ,  69  of the lines  50 ,  58  are arranged in the area of the electronic component  40  and can therefore be connected to it in an electrically conductive way. 
       FIG. 5  shows a cable harness  99  with two fixing elements  90 ,  91 , on which at least the contact elements of the electrical lines in  FIG. 1  are fixed. The contact elements  55 ,  59  of the electrical lines  50  or  59  are for example fixed on the fixing element  90 , whose ends  68 ,  69  are connected to the electronic component  40  in an electrically conductive way. The electrical lines  50 ,  58  are at least arranged in sections on the fixing element  90 , preferable the section of the line s 50 ,  58  that run along the fixing element  90 , as shown in  FIG. 6 . 
     For a fixation at the rechargeable battery  20  the fixing elements  90 ,  91  can each be fixed at at least two of the rechargeable battery cells  21 ,  22 ,  23 ,  24 . The fixing elements  90 ,  91  can therefore be for example affixed on the cell headers  87 ,  88  of at least two of the rechargeable battery cells  21 ,  22 ,  23 ,  24 , for example with the aid of a non-conductive adhesive connection. Alternatively only the contact elements  55 ,  59  can be construed self-adhesive as described above. 
       FIG. 6  shows the rechargeable battery  20  in  FIG. 1 , at which the cable harness  99  in  FIG. 5  is fixed, without the rechargeable battery housing  25  in order to clarify a third embodiment. Its fixing elements  90 ,  91  are therefore preferable affixed on the cell headers  87 ,  88  via suitable adhesive connections. The contact elements  55 ,  59  contact thereby the cell connectors  30 ,  39  in an electrically conductive way, as it is described in  FIGS. 2 and 4 .