DE19600417A1 - Contact element e.g. for storage battery pole - Google Patents

Abstract

A contact element for a pole (3) of a battery has a contact piece (14) with ridges (13) which cut into the pole surface so as to reduce to a minimum the contact resistance. The element is aligned so that the pressing of the contact piece is effected by a fastener which itself engages the battery pole. The fastener has an axis that is at right angles to the surface which the ridges engage. There is a recess near the contact piece through which part of the retaining post (4,5) can protrude. The surface concerned is the plane end face of the battery pole and the ridges have sharp edges.

Description

The invention relates generally to battery connections and specifically relates to a contact element for making egg ner detachable electrical connection to a pole Battery as well as one including this contact element Connecting device. The term "battery" should be used here representing all types of electrical energy storage applies, especially for electrochemical energy storage, like accumulators or rechargeable batteries.

Special requirements are placed on contact elements, used in electric vehicles or trolley buses, to the electrical connection between those used there Batteries and the electric cables of the drive motors and other power consuming machine parts. In The batteries in these vehicles must be regular to be changed and recharged, for which purpose, mostly even daily, the live cables disconnected and again must be reconnected to the battery. This daily assembly and disassembly of the electrical cables turns out to be cumbersome and is for warranty good electrical contact is problematic.  

So there are different contact systems in this area, for example, snap lock systems known which the manual coupling and uncoupling of the electrical cables united fold. With these contact systems, a reprodu positioning of the cable lug can be achieved, because of the inevitable formation of oxide or corro Sion layers at the contact points must have these systems but are regularly serviced and cleaned intensively. Without this intensive cleaning, the Contact resistance between the batteries and the contact elements so large that the power supply to each Machine parts are no longer guaranteed and malfunctions occur in the electrical systems.

Contact elements with a contact piece are known Bears parts that come together when joining contact piece and battery pole in a min the contact resistance cutting into a surface of the battery pole the. The surface chosen for this is the peripheral surface che of a cone-shaped outgrowth of the battery pole, the as a so-called battery plug like the rest of the Poles made of the material of the assigned battery electrode, usually lead can exist. One on one Battery pin attacking contact element, as in the DE 44 26 591 A1 discloses consists of a curved Stamped part in the form of a clamp, which is due to its Elasticity resiliently lays around the peg, taking after cut punched lugs into the lead of the tenon when the clamp is pushed over the pin. At another, known from DE-OS 26 19 690 tion form uses the contact element, a sleeve that on the Battery pin is rotated and in front of its inner surface has standing parts that run along one revolution Helix are arranged so that when turning the Sleeve like a tap in the peripheral surface of the Cut the tenon. Finally, from WO 92/11667 is a contact can be placed on the lead-like battery plug  ment known that two parallel walls curse with each other has openings that enclose the battery plug can eat. The inner surfaces of the openings are right provided with angular embossing, the edges of which are in the material of the battery plug penetrate when the two walls open one side compressed by a clamping screw that in order to lose their parallelism and the Tilt openings on the tenon.

With these known contact elements, the over gait resistance over a long time and several disassembly cycles be kept low throughout; regarding the defi Nation and reproducibility of the contact resistance However, this type of contact pressure is common with the clamping clamping of the battery pin is caused, not optimal. Also the assembly and attachment of this Contact elements are relatively complex.

The aim of the invention is to overcome these disadvantages.

The invention achieves this goal with a contact element for establishing a releasable electrical connection a pole of a battery, with a contact piece, the Erhe exercises that occur when joining the contact piece and battery pole under contact pressure in a transition resistance reducing manner in a surface of the bat Cut the poles with the contact element turned in is that the pressing of the contact piece by a on the battery or on a part that is fixed to it Fasteners is effected.

The pressing of the contact piece is thus done by a device Curing agent causes, which - unlike in the above. was standing the technology - on the battery (or a fixed part) attacks and thus the reaction forces of the evoked Contact pressure against the battery (or the fixed part) supports, whereas the above-mentioned State of the art only one  jamming enclosing the battery plug without any Support the associated fastener on the Battery teaches.

The contact element according to the invention has the following advantages:

• - The depth of penetration of the surveys can be relatively accurate be set;
• - The contact element therefore allows for a long time and several disassembly cycles precisely defined and reproducible low over gearing resistance; and
• - The assembly and fastening of the contact element simple.

Basically, the fastener can be in a peripheral area of the battery or at an area with the battery coupled part, e.g. B. attack a frame part. Preferential however, the attack occurs at the battery pole itself (Claim 2). The fastening particularly preferably engages means on a holding post of the battery pole, whose axis advantageously substantially perpendicular to the Surface in which the burial of the elevations done, is oriented (claim 3). With the surface it is advantageously the area from which cher the support post protrudes. The support post can then be a have and only have a holding function - unlike when standing of technology - no longer for establishing contacts and To worry about power line. It can therefore be made of one material (e.g. steel), which is as hard as or is harder than the contact piece with the elevations. Dude natively, it is also possible that it is in the waiter area in which the elevations are buried, around which the Act the end of the holding post facing away from the battery.

For simple and secure attachment of the contact piece to allow at the battery pole, the contact element one - particularly advantageous in the area of the contact piece  lying - recess for the passage of at least one Part of the support post or fastener (Claim 4). In the first case it occurs in the battery attached support posts through the contact element, the attachment is then carried out with the help of the attachment means on the side of the contact facing away from the battery elements. In the second case, the fastener can be a have shaft-like extension through the passage of the contact element and on the battery turned side of the contact element on the contact pole, for. B. with With the help of a thread.

Basically, the surface in which the survey is located dig in, have a curved or stepped shape. Easier and to achieve the same as possible depth of penetration for all surveys, however, is the surface around a substantially flat end surface of the Battery terminals. Accordingly, the surveys are advantageous arranged at the same level; the easiest is this realized by an essentially flat surface on the con Clock with local surveys that are attached to the End surface are designed such that they are under the Influence of a perpendicular to the named surfaces Cut contact pressure in the end surface (claim 5). To the to achieve the desired contact resistance reliably, the surveys are particularly advantageous in the form of nop pen or ribs formed.

For the particularly reliable achievement of a desired the contact points have low contact resistance Contact piece advantageous the shape of ribs, which form sharp-edged cutting edges (claim 6). Through this Measure penetrate them in a particularly reliable manner existing oxide, corrosion or dirt layers in the contacted battery pole area and thus generate especially bare contact points at the locations concerned. With each assembly, a particularly clean contact is new  created area, which also makes the contact resistance under particularly adverse conditions during extended operation without constant maintenance work on a constant remains low.

In this context, the following should be considered aside mentioned prior art: From EP 0 052 384 A1 it is known for a detachable connection contact for High-current conductor to reduce power losses by voltage drop at least one of the contact surfaces of the To be provided with sharp-edged roughness tips. These tips are designed so that they are solid Deform the contact surface more easily than a completely flat surface. This serves - unlike in the support of a rigid body, the only three support points - a multitude of contact points and thus to create a relatively large contact area. That mecha nism differs fundamentally from the effect of contact element according to the invention, the elevations themselves not deform, but, on the contrary, into the Cut the ordered contact surface of the battery pole.

Both technically and operationally advantageous is a formation of the contact element, in which the elevations on the contact piece circular or circular are ribs with a sectional shape (claim 7). Especially ders ribs on several concen- tres are advantageous tric arcs arranged (claim 8). Alternatively can the ribs also z. B. substantially straight run (claim 9), preferably preferably substantially Chen in the radial direction, based on a central axis of the Battery pole (claim 10).

Another advantageous measure to achieve a particularly high reproducibility of contact resistance lies in the provision of funds, in particular of Form-locking means, which ensure that in the contact  state the contact piece relative to the battery pole a centered or fixed position (claim 11). As a result, the surveys always come back to be in the same position on the battery pole surface (in In the former case of centering, this only applies to a rotation around a specified axis. In the case of um this axis concentrically arranged in a circle gene, e.g. B. Ribs, however, this corresponds to the then present rotation variance of an absolutely fixed posi tion).

The holding post advantageously consists of a in the battery pole anchored retaining bolt and one from its end outstanding retaining pin of smaller diameter, the the means for centering or fixing thereby formed are that the recessed area of the recess has an end section of the retaining bolt can positively accommodate and where - if the contact element has a recess - this can hold the retaining pin (claim 12).

Sling means are advantageously provided to an outer limit for the depth with which the elevations can the surface of the battery pole can penetrate too defi kidneys (claim 13). Generally only part belongs the sling to the contact element, whereas the other right part is to be assigned to the battery pole. So the Kon tact piece advantageously a stop surface, which in the we substantially parallel to a surface bearing the surveys surface and fits to a suitable counter surface is laid. The counter surface on is particularly advantageous Support post formed, preferably in the form a ring shoulder. The stop surface on the contact piece is particularly preferably by one, in particular the off saving surrounding, recessed area in the elevation gene formed supporting surface and dimensioned so that it can rest on the counter surface on the support post.  

To achieve a particularly simple structure of the contact elements are the means for centering or fixing the Contact piece advantageously combined with the lifting gear. For example, the top surfaces of those mentioned above Ring shoulder and the above-mentioned deepening the An Form impact agents, and limit these cover areas the edges by interlocking interlocking Form means for centering or fixing.

To achieve a reproducible positioning of the con clock element also with respect to the angle and possibly for ver avoid twisting when tightening a pressure nut an anti-rotation device is preferably provided, which ensures that the contact in the assembled state piece is fixed relative to the battery pole against rotation (Claim 14). The twist is particularly preferred achieved by positive locking (claim 15).

To achieve good reproducibility and adjustability of the contact resistance, it is particularly advantageous that Concentrate the elevations in the form of a circular arc trisch with the recess or with straight training run radially to the recess (claim 16).

If the contact element for producing the electrical Connection z. B. ge on the face of a retaining pin to be pushed (or - accordingly - a fastener gungsstift by the contact element for attachment to Contact pole is to be inserted), the recess is in front partially a bore (claim 17). Another advantage However, there is a possibility that the contact element fork-like over the jacket side of a holding element, for. B. push the retaining pin. The recess is in front of this partially open to the side edge of the contact element, see above that the contact element is in particular fork-shaped (An Proverbs 18). This measure allows the contact element be guided from the side to the retaining pin and then  possibly by shifting in the axial direction of the support post positively up on the end portion of the retaining bolt what the centering does. Especially before part of the width of the open to the side margin Recess smaller than the width (i.e. generally the Diameter) of the recessed area, so that according to the above mentioned axial displacement (with which the positive Receiving the end portion of the retaining bolt in the recessed th area) the contact element is no longer is removable from the support post. By this measure needs the contact surface that serves to mediate contact between the contact piece and the battery pole surface itself fork-shaped contact element to no shear forces wear - unlike the contact elements mentioned above the prior art in which the contact touch at the same time for a frictional mechanical connection between the contact element and the battery pole.

In particular with a fork-shaped contact element, the Ver rotation lock advantageous by a in the recess gripping, (opposite the battery) fixed link, e.g. B. in the form of a nose or a knob, formed (An Proverb 19).

To achieve a defined low transition resistance Such a training is also advantageous, a noticeable intermediate in the contacted state space between the surface of the con tactpiece and the surface in which the elevations incise remains (claim 20). This ensures that just make the elevations contact and leave room for material displaced by the penetration as well as on the Surface contaminants and the like.

The penetration of the surveys - not theirs Deformation - to cause, they preferably consist of a harder material than the battery pole in the area of  Surface in which the elevations cut (An Proverbs 21).

The invention is also based on a connection device a contact element according to one of the above designs directed to the releasable attachment of the Contact element on the battery pole includes fasteners, which on the battery or a part fixed to it, and attack the battery pole in particular (claim 22). Regarding the different possible characteristics and Ausge events as well as the advantages is expressly referred to Reference made above to the contact element, which are also valid for the connection device.

For detachable connection of the contact element to the battery riepol the fastening means preferably comprise a Pressure device, which is particularly advantageous with the holding Post of the battery pole is connected or connectable and to exert the contact pressure on the contact piece of the Kon Clock elements is designed (claim 23). This pressure direction can be permanently with the contact element or the Battery (especially the support post) or can be a separate part, which only with the Assembling the contact element and the battery becomes.

The contact pressure is preferably determined by an inside / outside Engagement connection, e.g. B. causes a screw connection. For this purpose, the pressing device has at least a part an inside / outside engagement connection, in particular a pressure screw or nut acting on the support post ter (claim 24). The pressing device can also be a Have snap lock (claim 25), also Can be part of an inside / outside engagement connection.

With the contact element and designed according to the invention the connecting device and the further developments thereof  So can a reprodu with simple assembly and disassembly easy and safe positioning of the contact element be achieved, which is a first requirement for the Ge guarantee of a constant contact resistance represents. Due to the local penetration of the contact piece existing surveys is a new with each assembly created a clean contact surface and remains the transition withstands even long periods of operation without expensive un maintenance work at a constant value.

A number of features of the subclaims and the front lying description are also with a contact element or advantageous in a connection device in which or the pressing of the contact element by not the battery (or a solid part) Means is effected (for example by means as in the beginning mentioned prior art). It is therefore the reservation declares independent protection - without which the pressing relevant feature complex of claim 1 - to all Features of the claims and the present Be writing - individually and in any combination judge.

The invention will now be further elucidated by way of example play and explained the inserted drawing. In the drawing shows:

Figure 1 is a partial longitudinal section through a connection device with contact element and a battery pole, in the contacted state.

FIG. 2 shows a bottom view of the contact element from FIG. 1, with a holding pin being shown in section;

Fig. 3 is a side view similar to Fig. 1 of another embodiment;

FIG. 4 is a bottom view corresponding to FIG. 2 of the contact element of FIG. 3; and

FIGS. 5a and 5b is a sectional view of contact ribs long ent lines BB of Fig. 2 and 4 in two different embodiments.

Parts in the drawing are functionally identical or similar marked with the same reference numerals.

Commercial batteries or accumulators consist of a housing block in which the individual batteries are housed and through which a positive and a negative battery contact pole is guided. In Fig. 1, part of such a housing block 2 and a battery contact pole (hereinafter referred to as battery pole) 3 is shown in pieces, which is guided through the wall of the housing block 2 . The battery pole 3 consists at its base 3 a of an electrically highly conductive lead alloy and has a holding post, consisting of holding bolt 4 and holding pin 5 . The retaining bolt 4 has great strength and is largely cast into the base 3 a of the battery pole 3 , only a small part protrudes beyond it. The retaining bolt 4, which is usually made of steel, carries a retaining pin 5 , which is provided with a thread 6 at its free upper end. A fastening means such as a plastic wing nut 8 , a star grip or the like can be screwed onto this thread in order to clamp a contact element 12 to the battery pole 3 . Such screwable fasteners are made captive by the opening of the uppermost part of the threaded pin 5 and, in preferred embodiments, can be assembled in a robot-friendly manner. Wing-like extensions 7 on the holding bolt 4 inside the base 3 a of the battery pole 3 prevent the twisting or triggering and falling of the holding bolt 4 out of the base 3 a of the battery pole 3 .

On the holding pin 5 a link 9 is arranged in the form of a side nose, which - as will be explained in more detail below - serves as an anti-rotation element for the contact element 12 in the assembled state.

Since the retaining bolt 4 used for the attachment of the contact element 12 and its set screw 5 are made of an iron metal in the preferred exemplary embodiment, the electrical current is conducted essentially in direct contact from the contact element 12 to the base 3 a of the battery pole 3 . One might think that made in particular of brass or a copper alloy Kontaktele element so as to form, for example as a perforated disc, that the largest possible contact area to the base 3a of the Batte riepols 3 is formed. Between such lying flat contact zones and the free, but the retaining bolt 4 surrounding at the foot ring surface of the base 3a of the battery terminal 3 to form oxide films and corrosion sites or oily soils are deposited from. All of these phenomena affect the electrical conductivity of the contact transition.

The contact element 12 therefore has no flat contact zone, but a plurality of elevations 13 , preferably in the form of nubs or ribs, the surface of the base 3 a of the battery pole in the free ring when mounting the contact element 12 through any current conduction-inhibiting layers 3 are pressed in when a contact pressure is exerted on the contact element by means of the wing nut 8 or another fastening means.

In the embodiment of FIGS. 1 and 2, the elevations 13 are formed as annularly arranged and extending ribs which have the shape of circular arc pieces, as shown in FIG. 2.

In the embodiment of FIGS. 3 and 4, on the other hand, the elevations are designed as rectilinear ribs which are arranged in a radial manner (in relation to the position of the center axis of the retaining bolt 5 in the assembled state). The angle between two adjacent ribs is preferably between 15 ° and 90 °, here approximately 30 °.

In both embodiments, the contact element 12 has a recessed central area on the contact side of its contact piece 14 , which can be placed on the exposed part of the retaining bolt 4 . This recess 15 thus forms a stop for the attached contact element 12 and is dimensioned in relation to the free height of the retaining bolt 4 and the height of the elevations 13 so that a predetermined maximum depth of penetration of the elevations 13 into the battery terminal when the contact element 12 is placed and clamped 3 results.

Further details of the contact element 12 can be seen in FIGS. 2 and 4. Accordingly, it essentially consists of a contact piece 14 and a cable socket 16 . The cable socket 16 is tubular in the case shown and is squeezed to fix an electrical cable 17 in its central region. This tube-like design of the Ka belfassung 16 makes them at the same time also particularly suitable for connecting additional cables, for example for connecting jumper cables. In other (not shown ge) embodiments, the cable socket 16 can be designed as a U-shaped deformable clamping piece; alternatively, the electric cable 17 can also be connected cohesively to a suitable socket 16 or a comparable connecting piece.

The contact piece 14 is disc-shaped and has a recess 18 for the implementation of the threaded pin 6 . In the illustrated embodiments, this recess is designed as a radial incision, the contact piece 14 thus has an overall shape of a contact shoe, which grips around the retaining pin 5 and the anti-rotation element attached thereto and receives it between its two prongs. In other (not shown) embodiments, it is, depending on the fastening means used, formed as a simple through hole or bore. For receiving a lateral anti-rotation member, the through hole can also be designed in the manner of an elongated hole. The exact dimensioning of this cutout 18 in turn depends on the dimensions of the insertable set screws 5 , which are generally standardized. Usually the set screws for the positive and negative battery pole have different diameters. The different contact elements with correspondingly dimensioned cutouts can therefore not be interchanged.

For safe and reproducible positioning of the contact element 12 Kon serves the recessed central region 15 on the underside, which can be slipped over the free-standing part of the retaining bolt 4 and is used by positive engagement to center the contact element 12 . That is - since the diameter of the retaining bolt 4 is larger than that of the grub screw 5 - at the transition between the two parts, an annular shoulder, which takes over the Zen tration function and in particular prevents the contact element 12 from being mounted in the direction of the radial incision in the assembled state shifts and drops off the battery pole 3 . In addition, the recessed central area 15 and the annular shoulder form an air gap, which allows compensation for changes in the depth of penetration caused by wear or aging.

In the illustrated embodiment, the gene rippenförmi elevations 13 are formed as sharp cutting edges which extend along a circular arc and spaced apart circular arcs (Fig. 2) or radially disposed straight sections (Fig. 4) form. These cutting edges can e.g. B. have a height of about 1.5 mm. In cross section they can have the shape of a structure symmetrical to the direction of penetration, generally a triangle, in particular an isosceles triangle ( FIG. 5a). The inclination of both flanks is then approx. 60 ° (based on the contact surface).

In another embodiment, the cutting edges in cross-section have the shape of a structure asymmetrical to the direction of penetration, for example a right-angled triangle ( FIG. 5b), the flank inclination of which, for. B. 90 ° and its other flank inclination z. B. is 45 ° (based on the contact surface).

These preferred embodiments allow a good mechanical ULTRASONIC cutting and thus a clean contact surface between the contact element 12 and battery. 3 Of course, the ribs 13 can also be designed differently and / or distributed over the contact surface, for example they can run in the form of several concentric arcs. It may be expedient to dimension the height of the ribs 13 in such a way that, with the depth of penetration usually desired or even when the maximum depth of penetration is set, a permanent finite space is ensured between the surface carrying the ribs and the facing contact surface of the battery pole 3 . This guarantees that oxide layers or other foreign materials that may be present do not inhibit the desired penetration depth. In the embodiment shown in Fig. 2, the cutting edges can only penetrate with their tip area, in other embodiments, however, a greater penetration depth is possible.

When connecting the contact element described above to the pole of a battery, the clamping device, in the illustrated case the wing nut 8 , is loosened so far that the contact piece 14 can be pushed over the retaining bolt 4 . Depending on the construction of the fastening means used, the recess in the contact piece - as mentioned above - is formed as a hole or as a radial incision. In the former case, the contact element must be pushed over the entire set screw 5 , in the latter case it can be inserted laterally before it can be slid over the upper part of the holding bolt 4 with its recessed central region 5 . He then engages around the anti-rotation member 9 and is thereby fixed against rotation Ver.

In both cases, simple and reproducible assembly is guaranteed. In other (not shown) embodiments, security against rotation can also be achieved by another non-rotating variant shaping of the contact element and the retaining pin (e.g. square or other polygonal shape). It is also understood that the Kontaktele element can be firmly connected to the fastening means and both can only be solved or put together. Instead of the screw nut 8 shown , another fastening means can also be used, e.g. B. a snap lock.

By varying the contact pressure, e.g. B. with the screw benmutter 8 , the depth of penetration can be varied and thus a desired contact resistance can be set.

Claims (25)

1. Contact element for establishing a releasable electrical connection's rule to a pole ( 3 ) of a battery, with a contact piece ( 14 ) carrying bumps ( 13 ), which when the contact piece ( 14 ) and battery pole ( 3 ) are put together under contact pressure cut in a manner reducing the contact resistance into a surface of the battery pole ( 3 ), the contact element ( 14 ) being set up in such a way that the pressing of the contact piece ( 14 ) is brought about by an engagement of the fastening means on the battery or on a part fixed thereto. 2. Contact element according to claim 1, wherein the fastening means acts on the battery pole ( 3 ). 3. Contact element according to claim 2, wherein the fastening supply means on a support post ( 4 , 5 ) of the battery pole ( 3 ), the axis of which, in particular, is oriented substantially perpendicular to the surface into which the bumps of the elevations ( 13 ) are oriented is. 4. Contact element according to claim 3, which has a recess, in particular in the region of the contact piece ( 14 ), for the passage of at least a part ( 5 ) of the holder ( 4 , 5 ) or the fastening means. 5. Contact element according to one of the preceding claims, in which the surface is a substantially flat end face of the battery pole ( 3 ) and on the contact piece ( 14 ) a substantially flat surface with local elevations ( 13 ), in particular in the form of knobs or Ribs are provided, which are designed to bear against the end face, such that they cut into the end face under the influence of a contact force applied perpendicular to the said faces. 6. Contact element according to one of the preceding claims, in which the elevations ( 13 ) on the contact piece ( 14 ) are ribs which form sharp-edged cutting edges. 7. Contact element according to one of the preceding claims, in which the elevations ( 13 ) on the contact piece ( 14 ) are circular or circular ribs. 8. Contact element according to claim 6 or 7, wherein the ribs ( 13 ) are arranged on one or more concentric arcs. 9. Contact element according to claim 6, in which the ribs ( 13 ) run substantially rectilinearly. 10. Contact element according to claim 9, wherein the ribs ( 13 ) extend substantially in the radial direction, based on a central axis of the battery pole ( 3 ). 11. Contact element according to one of the preceding Ansprü surface, in which means, in particular form-locking means, ensure that in the assembled state the contact piece ( 14 ) lies relative to the battery pole ( 3 ) in a centered or fixed position. 12. Contact element according to claim 11, wherein the Haltpfo most ( 4 , 5 ) from a in the battery pole ( 3 ) anchored retaining bolt ( 4 ) and from its end protruding retaining pin ( 5 ) of smaller diameter, and wherein the means for centering or Fixation are formed in that the recessed area ( 15 ) of the recess ( 18 ) can receive an end portion of the retaining bolt ( 4 ) in a form-fitting manner and, if necessary, that the recess ( 18 ) can receive the retaining pin ( 4 ). 13. Contact element according to claim 9, in which stop medium for defining the maximum cutting depth are provided. 14. Contact element according to one of the preceding Ansprü surface, in which an anti-rotation ensures that in the assembled state, the contact piece ( 14 ) is fixed relative to the battery pole ( 3 ) against rotation. 15. Contact element according to claim 14, wherein the Ver Anti-rotation is achieved by positive locking. 16. Contact element according to one of claims 4 to 15, in which the elevations ( 13 ) on the contact piece ( 14 ) are arcuate and concentric with the recess or radially ( 18 ) ribs extending to the recess. 17. Contact element according to one of claims 4 to 16, wherein the recess ( 18 ) is a bore. 18. Contact element according to one of claims 4 to 17, wherein the recess ( 18 ) to the side edge of the contact element Kon ( 18 ) is open so that the contact element ( 18 ) is in particular fork-shaped. 19. Contact element according to one of claims 4 to 18, wherein the anti-rotation device is formed by a fixed member ( 9 ) engaging in the recess. 20. Contact element according to one of claims 5 to 19, in which in the assembled state there is a noticeable space between which the elevations ( 13 ) bear the surface of the contact piece ( 14 ) and the surface into which the elevations ( 13 ) cut. 21. Contact element according to one of the preceding claims, in which the elevations ( 13 ) consist of a harder material than the battery pole ( 3 ) in the area of the loading area in which the elevations ( 13 ) cut. 22. Connection device with a contact element ( 14 ) according to one of claims 1 to 21, which comprises releasable attachment of the contact element ( 14 ) to the battery pole ( 3 ) fastening means which on the battery or a part fixed thereto, in particular on the battery pole ( 3 ) attack. 23. Connection device according to claim 22, wherein the fastening means comprise a pressing device ( 8 ) which is connected or connectable to a holding post ( 4 , 5 ) of the battery pole and for exerting the pressing force on the contact piece ( 14 ) of the contact element ( 12 ) is designed. 24. Connection device according to claim 23, characterized in that the pressing device ( 8 ) has at least part of an inside / outside engagement connection, in particular a pressing screw or nut ( 8 ) engaging on the holding post ( 4 , 5 ). 25. Connection device according to claim 23, characterized records that the pressing device a snap has conclusion.