Abstract:
A connector assembly includes a battery pole terminal, a measurement element for a battery sensor, and a ground wire in the battery. The measurement element has two connections for connecting to the battery pole terminal and/or the battery cable, such that an electrically-conductive connection exists between the ground wire and the battery pole terminal by means of the measurement element. At least one of the connections is connected to the battery cable or the battery pole terminal by way of a force-locking or interference connection.

Description:
BACKGROUND OF THE INVENTION  
     Field of the Invention  
       [0001]     The invention relates to a connecting configuration by way of which a measurement element in a battery sensor can be connected to a pole terminal in a battery and/or battery cable of the battery. The configuration can thereby be used particularly in motor vehicle batteries, to which a measurement sensor is attached that serves to detect different parameters of the battery, for example the battery current.  
         [0002]     The constant evaluation of the battery parameters keeps track of the state of charge of the battery. In addition to the current state of charge, the battery wear status and/or other battery dependent conditions, for example the prognosis of the battery temperature for the next motor vehicle start-up are also of interest.  
         [0003]     In order to detect these variables and particularly to measure the battery current in a motor vehicle battery, it is known to integrate a battery sensor in the battery, particularly in the battery pole niche, said battery sensor comprising a measurement element, the captured data of which is evaluated. To determine the battery current, the measurement element is a measurement resistor, particularly a precision resistor.  
         [0004]     With the prior art configuration, where the measurement resistor is arranged between the pole terminal in a battery and its ground wire, a weld joint or a soldered joint is provided between the measurement resistor and the pole terminal or between the ground wire and the measurement resistor. In addition to the mechanical connection of the components, this weld joint guarantees the necessary electrical line, but is nevertheless costly to manufacture.  
       SUMMARY OF THE INVENTION  
       [0005]     It is accordingly an object of the invention to provide a connector for a measurement element of a battery sensor which overcomes the above-mentioned disadvantages of the heretoforeknown devices and methods of this general type and which provides for an improved connector for a measurement element in a battery sensor using the battery pole terminal in a battery and a battery cable in a battery (ground wire and/or wire on + side) such that the current conducts at the lowest possible resistance across the connecting part and is furthermore easy to manufacture.  
         [0006]     With the foregoing and other objects in view there is provided, in accordance with the invention, a connector assembly, comprising:  
         [0007]     a battery pole terminal;  
         [0008]     a battery cable for a battery connection;  
         [0009]     a measurement element for a battery sensor, said measurement element having a first connection for connecting to said battery pole terminal and a second connection for connecting to said battery cable, forming an electrically conductive connection between said battery cable and said battery pole terminal via said measurement element;  
         [0010]     wherein at least one of said first connection and said second connection is a force-locking connection.  
         [0011]     A force-locking connection—also referred to as a friction lock, a frictional connection, or an interference connection—is one that connects two elements together by force external to the elements, or to at least the locked element. This is opposed to a form-locking or positive connection, which is provided by the shapes of the elements themselves.  
         [0012]     The invention is based on the concept of simplifying the connection between the measurement element and the battery pole terminal, and the connection between the measurement element and the connection of the battery cable such that an interference connection is produced between these elements, thereby dispensing with a relatively costly weld joint. The electrical conductivity which is essential for the connector is achieved across the connecting region by virtue of the interference connection, in other words, the direct contact subject to contact pressure between the conducting elements. This is particularly valid if the measurement element is configured as a measurement resistor, in other words, a metallic component, and the corresponding connector in the terminal pole and/or the battery cable is similarly formed from electrically-conductive, metallic material for instance, so that a precise alignment of the elements towards one another is not necessary. If other only regionally electrically-conductive components such as pressured circuits, film wires or the like are used as the measurement resistors and/or as the connecting element on the side of the pole terminal and/or the battery wire, an easily producible, electrically-conductive connection between these elements can be ensured by means of an interference connection, if the conductive parts are aligned respectively to one another. In this way, the battery cable can be both the ground wire and the wire on the + side of the battery.  
         [0013]     The force-lock connection is preferably designed as compression fit, i.e. an interference connection whereby the parts which are to fit together are joined using high pressure or by shrinking and/or stretching. Alternatively a compression fit can also be used in which the parts to be connected are joined together in the same way as with a press fit, but nevertheless do not have particular fit but are merely oversize. By way of example, one of the surfaces can be keyed or knurled. A compression method can also be understood as a method by means of which a subsequent distortion generates the tight fit. These types of method can be used, provided an adequate surface contact of the components to be connected is ensured, so that the current can be conducted with the lowest possible resistance via the connecting part. Air gaps should be particularly avoided in the region of the connecting part. A weld joint can be executed in addition to the interference connection or compression in each instance.  
         [0014]     Other features which are considered as characteristic for the invention are set forth in the appended claims.  
         [0015]     Although the invention is illustrated and described herein as embodied in a connector for a measurement element in a battery sensor, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.  
         [0016]     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0017]     The sole FIGURE of the drawing shows a partly cross-sectional perspective view of a connector according to the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     Referring now to the drawing in detail, the connector  10  shown therein contains a battery pole terminal  12 , which is attached around a battery post or pole terminal  14  of a non-illustrated battery and which is preferably disposed in a protected location in the battery pole niche of the battery. The battery pole terminal  12  comprises a substantially annular region  13 , which encloses the battery pole  14  when the battery pole terminal is fitted. Two legs  15  separated from one another are attached to this annular region  13 , which allow an expansion of the annular region  13 , whereby the legs  15  are pressed apart and spread out. To attach the battery pole terminal  12  to the battery pole  14  in a battery, a connecting element, e.g. a screw  16  which screws into a nut  17 , is guided through the corresponding hole in the legs  15 . A fixed connection between the annular region  13  of the battery pole terminal and the battery pole  14  is produced by tightening the nut  17 .  
         [0019]     The battery pole terminal  12  also comprises another leg  19 , arranged on the side of the battery pole terminal  12  facing away from the legs  15 , and similarly projects outwards from the annular region of the battery pole terminal. A socket is integrated into the leg  19  in the form of a through-hole  22  for example, into which a connection bolt  18  of a ground wire  21  can be introduced and fixed. Alternatively, if another device for fixing the position of the connecting bolt  18  is provided, in the battery pole niche itself for example, the leg  19  and also the socket can be dispensed with. An indentation can be provided instead of a passage opening  22  for the bolt  18  of the ground wire  21  into which the connection bolt  18  is inserted.  
         [0020]     An insulating sleeve  20  is attached to the connecting bolt  18  where it passes through the similarly electrically-conductive battery pole terminal  12 , the insulating sleeve preferably being manufactured from an electrically-conductive material, brass or copper for instance, thereby preventing a direct conduction of electrical current through the bolt  18  into the battery pole terminal  12  bypassing the measurement element  30 . The sleeve must be dimensioned such that it insulates the entire area where the connecting bolt and the pole terminal  12  could come into contact with one another.  
         [0021]     The assembly  10  further contains a measurement element  30 , which is designed as a precision resistor for instance, and is similarly formed from metallic materials, brass and copper. The use of a magnetic measurement element instead of a precision resistor for example is also considered. Holes  32 ,  33  are formed in the measurement element  30  at predetermined locations, the holes being dimensioned such that they can contract into a tight fit at the connecting bolt  18  of the ground wire  21  and/or at the battery pole terminal  12  with connecting spigots  34 ,  35 . The diameter of the spigots  34 ,  35  is thus fractionally greater than the diameter of the holes  32 ,  33 . In the embodiment shown, holes are provided on the measurement element  30  whilst corresponding connecting spigots  34 ,  35  are formed at the connecting pulse of the ground wire  18  and/or the battery pole terminal. It is also possible to provide the measurement resistor and/or the measurement element  30  with corresponding projections, with recesses being provided in the battery pole terminal and/or the connecting bolts of the ground wire. Instead of the oversize described, the spigots  34 ,  35  can be provided with ribs or a knurl with oversize, the spigots are compressed into the holes or the recesses by means of subsequent distortion.  
         [0022]     The positions for the holes  32 ,  33  and thus the press connections are disposed on the measurement element such that current fed from the connecting spigot  18  of the ground wire flows via the press fit  37  between the connection spigot  34  of the connection bolt  18  and the measurement element  30  into the measurement element  30 , and flows through the measurement element  30  and via the tight fit  36  between the measurement element  30  on the connection spigot  35  of the battery pole terminal  12  in the battery pole terminal and vice versa. The path of the current flow is indicated by means of arrow I. The connection spigot  35  at the battery pole terminal  12  can be configured at each suitable position in the battery pole terminal provided the desired current flow path is ensured. The current flow through the measurement element is evaluated in order to detect the battery parameters.  
         [0023]     Instead of the arrangement shown, in which one end of the measurement section in the measurement element  30  is directly connected to the battery pole terminal  12 , the measurement resistor and/or measurement element  30  can be inserted between two segments of the ground wire, whereby a connection is produced between measurement element  30  and ground wire  21  across a tight fit in a similar manner to the connection  37  in each instance. It is also possible to provide a tight fit not at both ends of the measurement section of the measurement element  30 , in other words, not at the ends of the measurement section at which the current in the measurement section is fed and at the end at which the current is fed away from the measurement section, but rather only to design one of the connections over a tight fit, whilst the other connection is typically a weld joint or a soldered joint.  
         [0024]     The connector  10  further contains additional sensor components  40 , which are linked to the measurement element  30 , and are taken off and evaluated there if necessary. These sensor components  40  can also serve to fix the connector, in addition to fixing the connector between the pole terminal  12  and the battery pole  14  in the battery pole niche and/or at another position in the motor vehicle. This is particularly advantageous if the measurement element  30  is applied between two sections in the ground wire.  
         [0025]     The essential aspect of the invention lies in simplifying the conventional costly weld joint in order to integrate a measurement element  30  for a battery sensor in the arrangement in the battery pole niche, in particular between battery pole terminal  12  and ground wire  2  such that a connection bolt in the ground wire  21  and/or a connecting pin or spigot  35  in the battery pole terminal is connected to the measurement element  30  by means of a tight-fitting connection, an interference fit for example.  
         [0026]     This application claims the priority, under 35 U.S.C. § 119, of German patent application No. 10 2004 006 298.6, filed Feb. 9, 2004; the entire disclosure of the prior application is herewith incorporated by reference.