Repair procedure for an electrical connector, electrical connector and battery module

Abstract

The invention relates to a repair method for an electrical connector (100) with a conductor element (1) which is rigidly connected to an electrical or electronic component (5) via a connection pad (3). The repair method according to the invention is characterized in that the electrical connector (100) is cut open in the area of ​​the connection pad (3), after which a new contour for subsequent crimping is cut out of the part of the connection pad (3) connected to the component (5), after which sections (8, 9) of the contour are bent into a trough shape, and after which a round conductor (11) is electrically contacted and mechanically connected to the connection pad (3) by crimping as a replacement for the conductor element (1). The invention also relates to a suitable electrical connector (100) and a battery module with such an electrical connector (100).

Description

The invention relates to a repair method for an electrical connector according to the type defined in more detail in the preamble of claim 1.Electrical connectors are nowadays frequently realized via flexible line elements or flexible printed circuit boards which have one or more conductor tracks. In practice, such flexible line elements are also referred to as flexible films or, based on the English term "flexible printed circuit", as FPC connectors. They have many advantages over classic round conductors or cables. They are relatively light and cheap, require little space and all the conductive tracks are always in the same defined position. In order to be able to connect the (individual) flexible line elements easily to electrical or electronic components, the ends of the flexible line elements are often provided with so-called connection pads or welding pads. These are enlarged portions which are formed integrally with the flexible line elements or are connected to them during the production thereof.However, a disadvantage of such electrical connectors based on flexible line elements is that they are relatively sensitive to bends and impacts against edges, since the individual conductor tracks themselves are typically made very thin. In addition, breakages can occur after a strong thermal expansion due to pre-damage in production and / or due to a tapering of the conductor tracks. Occasionally, the flexible line elements are also prone to ageing, so that the material carrying the conductor tracks becomes brittle over time and therefore breaks can occur. This applies in particular when additional bends, impacts or vibrations occur. Moreover, a need for repair to any of the components connected via the electrical connectors may require that the flexible conductive member of the electrical connector be partially or completely removed.It is often the case that the flexible line elements are welded to the electrical or electronic components with their connection pads at the individual connection points to the latter. Singular laser welds are typically used here, which make good mechanical and electrical connection possible easily and efficiently within the available installation space. However, this leads to the flexible line elements not being removable as long as the welded joint itself cannot be renewed, for example due to poor accessibility. The renewed application of the welded connection also requires a corresponding outlay in terms of the device, so that, even if it can be renewed, the repair is typically possible reliably only in an industrial environment.In practice, this has the result that, in the event of a defect, the complete system must frequently be exchanged. Due to a comparatively favorable component, high failure costs are thus produced. This applies in particular, but not exclusively, to battery applications in which the electrical connectors are typically firmly welded to the individual battery cells, so that here typically a defect of the electrical connector always leads to an exchange of the complete cell module. In the event of repair, this causes significantly higher material costs than necessary, since the costs for a flexible line element, for example for tapping cell voltage, are very much lower than the costs of the individual battery cells. A basic solution could therefore provide that the complete flexible electrical connector, typically the complete flexible conductor set of a battery, is removed and subsequently reattached. However, this requires a design of the battery module which allows unrestricted access to the individual electrical connection points, since a pretreatment of the welding surface and a subsequent renewed welding of the conductor tracks or connection pads typically have to take place. The effort involved in such a repair, which typically can also be realized only in the industrial environment, is often so high that the monetary advantage of the repair compared to a complete replacement is minimal or not at all present.CN 214 849 442 U describes a solution in which connectors are inserted in place of the welded connections so that the complete flexible line elements can be exchanged as a whole. Such connectors have other disadvantages, however. In contrast to a welded joint, reliability is affected by many more different parameters. The plugs must therefore be of correspondingly high value in order to be able to realize an electrical connection comparable to the welded connection. They must be easily accessible for inserting the plug elements connected to the conductor tracks and accordingly require a lot of installation space. Moreover, they are more complicated to assemble, add additional weight to the initial system and add additional costs.U.S. Pat. No. 6,830,176 B2 describes a method for repairing a flexible conductor which is distinguished by insulated and uninsulated sections of its individual conductor tracks. If necessary, the electrical conductor can be cut. The flexible conductor can then be repaired via a special connecting element which is soldered in each case to the closest uninsulated sections adjacent to the separating point. The connecting element then forms a soldered-in bridging for the separating cut in the flexible line element. In this case, the non-insulated regions cause the risk of electrical contacting with the environment, which is undesirable. To repair such a flexible conductor, both affected points must then also be accessible for renewed soldering. As is also described in the U.S. Pat. No. itself, the exact positioning of the connecting element to be soldered on is very complicated in the case of closely adjacent conductor tracks. However, this is indispensable in order to reliably exclude potential short circuits and incorrectly connected conductor tracks.The object of the present invention is therefore to specify a very simple and reliable repair method for such electrical connectors having a line element which is fixedly connected to an electrical or electronic component via a connection pad.According to the invention, this object is achieved by a repair method having the features in claim 1, and here in particular in the characterizing part of claim 1. Advantageous further developments of the repair method are evident from the dependent claims dependent thereon. Furthermore, an electrical connector suitable for the repair method is specified in claim 4, advantageous embodiments also resulting here from the dependent dependent claims. Claim 7 also provides a preferred application for the easily repaired electrical connector in a battery module.In the repair method according to the invention, the existing connection pad is used to repair the electrical connection. For this purpose, the electrical connection is disconnected in the area of this connection pad, so that at least a part of the connection pad, which is firmly connected to the electrical or electronic component, remains on the electrical or electronic component. This part of the connection pad connected to the component is then used to cut out from it a new contour for a later crimping. Therefore, parts of the original connection pad are removed for this purpose. Subsequently, sections of this contour are bent in trough-shaped fashion in order to prepare them for the later crimping. Finally, in the repair method according to the invention, a conventional round conductor is used as a replacement for the line element which is defective or to be removed for other reasons, in that this round conductor is electrically contacted and connected to the connection pad by crimping.The repair method according to the invention thus creates from the connection pad which is already present and firmly contacted with the electrical or electronic component a device which can be crimped with a round conductor as a replacement for the line element. The line element can thus be replaced by the round conductor in the event of repair, wherein the method is correspondingly simple and efficient by using a fundamentally established, robust and reliable technique by crimping, which can be implemented with minimal apparatus complexity.According to a very advantageous development, the new contour can be cut out by punching. A simple punching tool, which can be realized, for example, in a suitable clamp for this purpose, in the basic type of a hole clamp, can thus be used to punch out the new contour required for crimping from the part of the connection pad connected to the component and lead to said part.In this case, it is in principle the case that it is sufficient here to configure the new contour such that corresponding protrusions, which could also be referred to as double wings, are available, which can be placed around an electrically conductive part, typically the inner conductor, of the round conductor and crimped thereto. This ensures, on the one hand, the electrical connection and contacting and, on the other hand, a mechanical connection is created between the round conductor and the connecting pad and, via the latter, the component connected to the latter.This contacting and connection, however, only offers a comparatively low strain relief of the round conductor. According to a preferred development of the repair method according to the invention, the contour can therefore have a connecting web and two double wings which are designed to engage around the inner conductor of the round conductor on the one hand and its insulation on the other hand after crimping. The double wing, which is placed around the inner conductor and crimped to the latter, ensures the electrical contacting. The second is placed around the insulation of the round conductor and crimped to this insulation. This portion serves to improve strain relief to provide a stable mechanical connection.As already mentioned at the beginning, such connection pads can be formed integrally with a respective flexible conductor track. The material of the connection pad is thus the same as that of the flexible line element. This is often only conditionally suitable for crimping. The electrical connector according to the invention therefore provides that the connection between the connection pad and the flexible line element is formed as a connection, according to a preferred development in particular as a soldered or welded connection. The electrical connector provided for repair is therefore designed such that the line element on the one hand and the connecting pad on the other hand have already been connected to one another during the production or the assembly of the electrical connector, in particular by soldering or welding. This creates the possibility of using a different material for the connection pad than for the line element. This material can now be in particular a material which can be soldered or welded more easily to the corresponding component and which, according to a preferred development, is designed in such a way that this material is suitable for later crimping to a round conductor. In particular, the material thickness can play a role here, which is typically designed to be greater than the material thickness of the flexible line element in order to enable a plastic deformation and thus crimping.A battery module according to the invention now comprises a plurality of individual battery cells and at least one electrical connector according to the invention.The repair method can thus be used for repair of flexible line elements in such a battery module, which can be installed in particular in traction batteries for electric vehicles. Such traction batteries have a very high cost proportion on the vehicle, so that here a simple and efficient repair for a cost-effective connecting element, which would otherwise lead to a complete replacement of the battery module, offers particular advantages. Fundamentally, however, the repair method can be used advantageously with all such electrical connectors.Further advantageous embodiments of the repair method according to the invention also result from the exemplary embodiment which is described in more detail below with reference to the figures.The following are shown: FIG. 1 shows a schematic illustration of the first steps for preparing the repair method; FIG. 2 shows a schematic illustration of further preparatory steps for the later crimping; and FIG. 3 shows the repair by connecting a round conductor via a crimping method.In the illustration of FIG. 1, an electrical connector 100 is shown in FIG. 1 a), which comprises a flexible line element 1, which is connected at its end illustrated here below via a welded connection denoted by 2, to a connection pad 3, which is also denoted as a welding pad. In the region of the flexible line element 1, a defect of whatever type is now to be present, so that repair of the electrical connection is necessary here. This defect is indicated in the illustration of FIG. 1 a) by an explosion symbol.An exchange of the complete electrical connector 100 is ruled out here because the connecting pad 3 is firmly connected via a welded connection denoted by 4 to a component 5 indicated merely in FIG. 1 a).In order to prepare the repair method, the connecting pad 3 is now cut along the section line denoted by 6 in FIG. 1 a). In FIG. 1 b), only the lower part of the connection pad 3 remaining on the component 5 is then left. This is again shown together with the welded connection 4. In order to prepare this part of the connection pad 3 for a later crimping, it is necessary to cut out a new contour from this connection pad 3, which contour is indicated accordingly in the illustration of FIG. 1 c ). This cutting out of the contour, which in this case has a continuous connecting web 7 and smaller and larger double wings 8, 9, can be realized, for example, by a punching tool.In the illustration of FIG. 2 a), this new punched-out contour of the connection pad 3 can be seen. In order to prepare the new contour for crimping, the two double wings 8, 9 are bent upwards along the dashed lines 10 in order to create a crimping trough in each case. In FIG. 2 b), this can be seen in a plan view and in a side view of the remaining part of the connection pad 3.In the illustration of FIG. 3 a), the illustration from FIG. 2 b) is now adopted again. On the remaining part of the connection pad 3 with the crimping troughs created between the double wings 8, 9, a round conductor denoted in its entirety by 11 is now positioned. This consists of an outer electrical insulation 12 which encloses an inner conductor designated 13 in its interior. In the exemplary embodiment shown here, this consists of a plurality of individual conductors. The round conductor 11 stripped at its end is now positioned in such a way that the region with the outer insulation 12 comes to lie in the crimping trough formed by the double wings 9, that with the inner conductor 13 exposed in the crimping trough formed by the double wings 8. In the illustration of FIG. 3 b), it can then be seen how the structure looks after crimping the double wings 8, 9, again in a plan view on the one hand and a side view on the other hand. The region with the double wings 9 is crimped around the insulation 12 of the round conductor 11 and thus ensures good strain relief. The region formed by the double wings 8 is crimped around the inner conductor 13 of the round conductor 11 and provides, on the one hand, a good electrical connection and, on the other hand, can also contribute to a certain part to strain relief. Overall, the defective connection of the flexible line element 1 can be replaced with a conventional round conductor 11 in a very simple and efficient manner using simple tools, such as a punching tool and a crimping tool.

Claims

Repair method for an electrical connector (100) having a line element (1) which is fixedly connected to an electrical or electronic component (5) via a connecting pad (3), characterized in that the electrical connector (100) is cut open in the region of the connecting pad (3), after which a new contour is cut out from the part of the connecting pad (3) connected to the component (5) for a later crimping, after which sections (8, 9) of the contour are bent in the shape of a trough, and after which a round conductor (11), as a replacement for the line element (1), is electrically contacted with the connecting pad (3) by crimping and is mechanically connected.Repair method according to claim 1, characterised in that the new contour is cut out by punching.Repair method according to claim 1 or 2, characterised in that a contour is used which has a connecting web (7) and two double wings (8, 9) which are designed to engage around an inner conductor (13) of the round conductor (11) on the one hand and its insulation (12) on the other hand after crimping.The electrical connector (100) for a repair method according to any one of claims 1 to 3, wherein the connection pad (3) is connected to the conductive member (1).Electrical connector (100) according to Claim 4, characterized in that the connection (2) between the line element (1) and the connection pad (3) is designed as a soldered or welded connection.Electrical connector (100) according to claim 4 or 5, characterized in that the connection pad (3) is formed from a material suitable for crimping.Battery module having a plurality of individual battery cells and at least one electrical connector (100) according to one of Claims 4 to 7.

Images