Connecting device with flux for disconnecting a connecting element in the event of a fault

Abstract

The invention relates to a connecting device (1) for electrically connecting at least two connections, having: - at least one connecting element (2) which is designed for conducting current between the at least two connections and has at least two contacting regions (2a, 2b) for electrical and mechanical connection to the respective connection, the connecting element (2) containing a metal material (3) and having a passivation layer (4) which forms at least in the event of a fault and encloses the metal material (3), and - a flux (8) which can be thermally activated by the fault-induced introduction of heat and is designed to remove the passivation layer (4) in the event of a fault which melts only the metal material (3) in a melting region (2c) of the connecting element (2), in order to sever the connecting element (2) in the melting region (2c).

Description

[0001] Connecting device with flux for separating a connecting element in the event of a fault

[0002] The invention relates to a connection device for electrically connecting at least two electrical terminals. The connection device comprises at least one connecting element designed for current conduction between the at least two terminals, with at least two contact areas for electrical and mechanical connection to the respective terminal, wherein the connecting element has a metallic material and a passivation layer that forms at least in one fault condition and encloses the metallic material. The invention further relates to a device with a connection device.

[0003] The focus here is on connection devices for electrically connecting the electrical terminals of at least two components of a device. Such a device could, for example, be an electrical energy storage device designed as a high-voltage energy storage device and used as a traction battery for an electric vehicle. Electrical energy storage devices typically comprise a multitude of components in the form of battery cells, which are interconnected by means of connecting elements in the form of cell connectors. These connecting elements may include integrated fuses that are designed to trip in the event of a fault and interrupt the current flow between the battery cells.For example, in DE 10 2022 124457 A1 a fuse is shown which is designed as a cross-sectional reduction in the cell connector and which is intended to melt in the event of a fault current flowing through the cell connector to interrupt the current flow between the battery cells.

[0004] To trip, fuses typically require a fault current in the form of an overcurrent. This current is higher than the operating current carried by the connector and thus generates sufficient heating to not only melt the connector material but also cause further effects such as movement of the molten metal, further heating of the liquid, and vaporization. These additional effects ultimately lead to the separation of the connector. In certain fault conditions, however, the fault current is not high enough to produce these effects beyond simply melting the material. As a result, current may continue to flow through the insufficiently melted cell connector, releasing further heat into the electrical energy storage device. This can lead to undesirable consequential damage.

[0005] The object of the present invention is to provide a connecting element for electrically connecting terminals in which a current flow is safely and reliably interrupted in the event of a fault.

[0006] This problem is solved according to the invention by a connecting device and a device with the features according to the respective independent claims. Advantageous embodiments of the invention are the subject of the dependent claims, the description, and the figures.

[0007] A connecting device according to the invention serves for the electrical connection of at least two electrical terminals. The connecting device comprises at least one connecting element designed for current conduction between the at least two terminals, with at least two contact areas for electrical and mechanical connection to the terminals. The connecting element has a metallic material and a passivation layer that forms at least in one fault condition and encloses the metallic material. Furthermore, the connecting device comprises a flux that can be thermally activated by heat input due to a fault condition. This flux is designed to remove the passivation layer in the molten area of ​​the connecting element in the event of a fault condition that melts only the metallic material in a molten area of ​​the connecting element, thereby cutting through the connecting element.

[0008] The invention further relates to a device with at least two components and a connection device according to the invention for connecting the components, wherein the terminals of the components are electrically and mechanically connected to the contact areas of the at least one connection element. The device is particularly preferably an electrical energy storage device with components in the form of energy storage cells or battery cells, and the connection device is a cell contacting system with a plurality of connection elements in the form of cell connectors, which are electrically and mechanically connected to terminals in the form of cell poles or cell terminals of at least two battery cells.

[0009] The cell connectors can be designed to connect multiple battery cells in parallel and / or in series. The electrical energy storage device is, in particular, a high-voltage energy storage device and is designed as a traction battery for an electrified motor vehicle according to the invention. The battery cells are preferably designed as cylindrical cells, which have a cylindrical cell housing in which a galvanic cell is arranged. The cell housing, in particular a housing cover of the cell housing, forms a negative cell terminal, which is electrically connected to a negative terminal of the galvanic cell. Electrically insulated from the cell housing, a positive cell terminal is guided through the housing cover of the cell housing and is electrically connected to a positive terminal of the galvanic cell. The cylindrical cells can, for example, be arranged vertically in a cell array.For example, to manufacture the cell assembly, several cylindrical cells can be arranged in a row to form an assembly on a strip-shaped, corrugated cooling element and attached, for example, by gluing. These assemblies can be joined together and mechanically connected, for example, by bonding.

[0010] The connecting elements consist in particular of a metallic material, especially aluminum, which is surrounded by a passivation layer. The passivation layer is in particular an oxide layer, which can be formed spontaneously, for example in the presence of oxygen, in the presence of a material surrounding the connecting element in the device, or through heat generation due to a failure, or intentionally, for example by passivation, anodizing, or chromating, on the surface of the metallic material. The passivation layer has a higher melting point than the metallic material and is therefore thermally very robust.

[0011] The fasteners are designed, for example, as flat metal parts and have a significantly reduced material thickness compared to their width and length. These fasteners can be manufactured from a sheet of metal using a cutting process, such as punching or laser cutting. This cutting process allows the fastener to be produced as a monolithic, one-piece component with a predetermined shape, such as a predefined contour. A subsequent bending process can then incorporate a profile into at least one of the fasteners. This profile might include deformation- or vibration-absorbing bulges or protrusions.The connection device can have differently shaped connecting elements, depending on how many components and thus how many terminals the respective connecting element is intended to contact, and what type of connection the components are to be, for example, a parallel connection and / or a series connection of several components. The connecting elements can, for example, be I-shaped or L-shaped and contact two terminals, or comb-shaped or finger-shaped and thus contact at least three terminals.

[0012] The at least one connecting element has contact areas, which are formed by predetermined sections of the monolithic component and are thus permanently and non-destructively connected to one another. The contact areas can, for example, be formed by end sections of the connecting element. In particular, each connecting element has at least one first contact area for contacting a first, for example, positive-pole-side, terminal of at least one component and at least one second contact area for contacting a second, for example, negative-pole-side, terminal of at least another component. The first contact areas can have a first shape, and the second contact areas can have a second shape different from the first, with the respective shape of the contact areas being adapted to the geometric shape of the terminal.In the case of connecting elements in the form of cell connectors, which connect round cells, the first, positive-side contact areas can be disc-shaped, for example circular disc-shaped, to be placed against the circular surface of the respective positive cell terminal, and the second, negative-side

[0013] Contact areas can be crescent-shaped or ring-segment-disc-shaped for placement against the ring-shaped surface of the housing cover forming the negative cell terminal.

[0014] In the event of a fault, the metallic material of the connecting element begins to melt, at least locally, due to the heating effect caused by the fault. This melting area, where the connecting element melts, can be a random region of the connecting element where the greatest heat is generated. However, the melting area can also be a defined region of the connecting element, which incorporates at least one fusible link. This integrated fusible link is designed to trigger in the event of a fault, interrupting the current flow through the connecting element and thus the current flow between the components connected via the connecting element. The fault condition is, in particular, a fault current flowing through the at least one connecting element and / or heat radiation and / or heat conduction of the component caused by a defect in at least one of the components.In the case of components in the form of battery cells, such a defect can be an internal short circuit, which can result in thermal runaway of the battery cell and a consequent heating of the cell housing of the battery cell.

[0015] In the case of the fuse forming the melting area, it is located away from the contact areas. For example, the fuse can be located adjacent to at least one of the contact areas, in particular to the at least one first contact area on the positive terminal side, or it can be integrated into a connecting area of ​​the connector that links the contact areas. The fuse is specifically integrated into a cross-sectional reduction of the connector or formed by at least one cross-sectional reduction. In other words, the connector has a reduced conductor cross-section, for example, a reduced width, in the melting area.It may also be provided that a cross-sectional reduction is formed between each contacting area of ​​a connecting element and the connection area, whereby only some of the cross-sectional reductions have a further cross-sectional reduction, called a fusible bridge, which forms the fusible link.

[0016] For example, the connecting element designed as a cell connector has at least one first cross-sectional reduction between the at least one first positive-pole contact area and the connection area, and at least one second cross-sectional reduction between the at least one second negative-pole contact area and the connection area, with each first cross-sectional reduction incorporating a fuse. This design is based on the understanding that, in the presence of a fault current, the cell connector typically melts from the positive-pole cell terminal. Therefore, the positive-pole first cross-sectional reductions of the cell connectors incorporate the fuses. The first and / or the second cross-sectional reductions can also each form a deformation-absorbing bulge. The bulges or...Bulges in a cell connector allow for a reversible change in length during the operation of the vehicle, for example due to driving-related vibrations, and thus prevent the cell connector from detaching, for example tearing off, from the cell terminals.

[0017] In the event of a fault, the material of the connecting element should largely melt in the melting zone due to the heating effect caused by the fault and be removed by further fault-related effects, thus interrupting the connecting element in the melting zone. However, it can happen that the heating effect of the fault and the associated heat input into the melting zone are insufficient to completely sever the connecting element. This can occur, for example, if the fault current is not an overcurrent that would instantly melt the melting zone, but rather its current intensity is within the range of the operating current, and the material of the connecting element heats up only slowly and / or insufficiently.In particular, if the temperature of the material exceeds the melting temperature of the material due to the heat input caused by the fault, but not the melting temperature of the passivation layer, a current continues to flow through the melt of the material enclosed in the passivation layer, which can lead to further heating of components of the device and to possible further short circuits.

[0018] To reliably interrupt the current flow even in such a fault condition, a flux is provided which, in its activated state, can chemically remove the passivation layer, allowing the melt to drip off or withdraw due to the flux-induced reduction of its surface tension. The flux can, for example, be a cesium-aluminum-fluorine compound, a potassium-aluminum-fluorine compound, or a zinc-aluminum compound. The activation temperature of the flux, i.e., the lower limit of its effective operating temperature, is close to the melting temperature of the material and is selected so that the flux is not activated by the operating current. For example, the flux can be activated by the heat of the melting material itself, i.e., by the thermal melt, and / or by the heat input caused by the fault, such as heat radiation or conduction from the defective component.

[0019] In particular, the connector has a coating that is applied to at least one side and at least partially of the connector and into which the flux is integrated or which consists of the flux. For example, the melting area forming the fusible link can be coated at least on one side. For example, the coating can be located within the bulge of the cross-sectional reduction and thus on the underside of the cell connector. In the melting area, the connector therefore has a multi-layered structure consisting of a material layer, two passivation layers covering both sides of the material layer, and at least one flux coating covering at least one of the passivation layers. The flux is thus located directly at the point of action, namely on the passivation layer, and can therefore remove it quickly and reliably in the event of a failure.Thermal activation liquefies the flux, which is solid or viscous in its unactivated state, and allows it to act on the passivation layer.

[0020] It is also possible for the flux to be applied not only at specific points, for example in the area of ​​the fusible links of all cell connectors in the cell contacting system, but also across the entire surface of the connection device, for example across the entire surface of the cell connectors of the cell contacting system. A support frame of the cell contacting system that carries the cell connectors can be free of flux or also covered with flux. In particular, the flux can be applied to the connection device, or at least to the connecting elements of the connection device, in such a way that a surface of the connection device, or at least of the connecting elements of the connection device, is substantially completely covered with the flux. For this purpose, the flux can, for example, be sprayed onto the connection device.In an alternative embodiment, the flux is integrated into or incorporated into a surface layer of the connecting device. This can be achieved, in particular, in the form of cavities or pores, from which the flux is released upon heating. This design offers the technical advantage that the flux is only activated when needed, namely during the heating process, thus enabling controlled and efficient release. Furthermore, it is conceivable to apply the flux to the connecting device by means of an immersion process. In this process, the connecting device, for example, the entire cell contacting system or just the cell connectors, is immersed in a flux bath before being mounted on the support frame, thereby achieving a particularly uniform and complete wetting of the surface.This method is particularly suitable for complex geometries of the connection device. Furthermore, it may be possible to apply the flux to the connection device using a coating process, such as electroplating or chemical vapor deposition. These processes allow for particularly precise control of the flux layer thickness and can lead to improved adhesion of the flux to the surface of the connection device. The diffuse application of the flux ensures that it is present precisely where it is needed, namely in the area of ​​the fusible link. Moreover, a diffuse application of the flux, compared to spot application, reduces the required amount of flux, which offers both economic and environmental advantages.On the other hand, the application of the flux over a large area is easier to implement mechanically and consequently involves lower production costs.

[0021] The coating can be a powder coating, a lacquer, and / or a paste. The coating can consist of the flux. Alternatively, the coating can include another material applied to the fastener for a different purpose, with the flux mixed into this material. Such a coating could, for example, be an adhesion promoter layer made of an acrylic lacquer, where the adhesion promoter layer additionally contains the flux.

[0022] The flux allows for a simple and cost-effective triggering of the fuse without additional space- and weight-intensive components, thus improving the fuse's separation capability in the low short-circuit current range.

[0023] It may be provided that the flux-containing coating is covered by a protective layer. The flux layer can thus be additionally covered by a protective layer. Providing a protective layer is particularly advantageous when the connecting element is embedded in another material that can react with the flux and thus reduce its effect on the passivation layer of the molten metal. This can occur, for example, in a device in the form of an electrical energy storage system where the energy storage cells and the cell contacting system are foamed (i.e., surrounded by a foam material, e.g., polyurethane foam), potted (i.e., surrounded by a potting compound, e.g., epoxy resin), or embedded in an injection-molded plastic.The protective layer is a protective layer that does not react with the flux, for example, a heat-resistant lacquer or a ceramic coating. The joining device may also include at least one carrier element attached to the joining element, which contains the flux. Such a carrier element could be, for example, a foam pad attached to the joining element, for example, in or adjacent to the melting area, and into which the flux is integrated, for example, in the form of a flux layer. After activation, the flux can flow over the surface of the joining element and remove the passivation layer, at least in the melting area.

[0024] In one embodiment of the invention, the connection device, designed as a cell contacting system, comprises at least one carrier plate on which the cell connectors are arranged and held. The flux is arranged, at least partially, between a top surface of the carrier plate and a bottom surface of the cell connector and is mechanically, and in particular by a metallurgical bond, connected to the carrier plate and / or the cell connector. The carrier plate or support frame is made of an electrically insulating material, for example, plastic. The cell connectors can be arranged and attached to the support frame, so that the cell connectors can be positioned at the cell terminals by arranging the support frame on a side of the cell assembly that has the cell terminals. For example, the cell connectors can have retaining areas that are mechanically connected to the support frame.For example, the cell connectors can be materially bonded to the support frame, for example by surrounding the holding areas with a material of the support frame, for example by overmolding.

[0025] After positioning the support frame equipped with the cell connectors on the side of the cell assembly containing the cell terminals, the cell connectors and cell terminals can be electrically and mechanically connected, for example by welding, in the area of ​​the respective contact areas. The flux areas are located specifically within the bulge of the cross-sectional reduction and thus positioned in the area of ​​the fusible link. Before the cell connectors are attached to the support frame, the flux can either be applied to the underside of the cell connectors, for example within the bulge, and additionally applied to the top side of the support frame when the cell connectors are attached. Alternatively, a multitude of flux areas can be placed on the top side of the support frame before it is equipped with cell connectors.

[0026] Flux layers are arranged. For this purpose, flux, for example in encapsulated, solid or viscous form, can be applied to defined locations on the surface. In a further process step, the cell connectors can be arranged on the support frame in such a way that the melt areas of the cell connectors overlap with or are positioned on the flux areas.

[0027] In a further embodiment of the invention, the cell contacting system includes a load distribution plate for absorbing forces acting on the energy storage device, which is arranged overlapping with the cell connectors. The flux is arranged, at least partially, between a top surface of the cell connector and a bottom surface of the load distribution plate and is mechanically connected to the load distribution plate and / or the cell connector. The load distribution plate is designed, for example, to absorb and dissipate forces resulting from accidents, thereby preventing deformation of the cell connectors and the energy storage cells. The load distribution plate can be formed by a housing cover of the electrical energy storage device or by a separate component arranged between the cell assembly and the housing cover.The flux areas can be arranged at the apex of the bulge in the cross-sectional taper on the upper side of the cell connectors and thus positioned within the fusible link area. For example, the flux areas can be arranged on the cell connectors, which are then covered by the load distribution plate. Alternatively, the flux areas can be arranged on the underside of the load distribution plate, so that by positioning the load distribution plate over the cell connectors, the flux areas are located at the fusible links.

[0028] It is particularly advantageous if the cell contacting system includes compression elements arranged between the load distribution plate and the cell connectors to absorb deformation of the load distribution plate. These compression elements act as a carrier for the flux and are designed to release the thermally activated flux. The compression elements are designed to absorb deformation of the load distribution plate in the direction of the cell connectors to prevent damage to the connectors. The compression elements can be located away from the melting areas, for example, away from cross-sectional reductions. The compression elements are made of a compressible material, particularly reversibly, such as a foam material like foam rubber or foam rubber. The compression elements can be manufactured, for example, by vulcanization.The compression elements are designed in particular as pads which can be attached to an upper side of the cell connector or the support plate and / or to the underside of the load distribution plate and are thus arranged between the load distribution plate and the cell connectors when the load distribution plate is arranged above the cell connectors.

[0029] The compression elements can incorporate the flux and thus additionally form carrier elements for the flux. After activation, the flux can flow over the surface of the cell connector and remove the passivation layer, at least in the melt zone. For example, the compression elements can be multilayered and comprise a foam layer and an adjacent flux layer. Alternatively, the compression elements can be segmented, comprising a foam segment and an adjacent flux segment, with the flux segment located adjacent to the melt seal. Preferably, the flux is highly concentrated, non-liquid, and incorporated into the pores of the foam material of the compression elements. In particular, the flux can be incorporated into the foam material during the manufacturing of the compression element.

[0030] For example, the flux can be added to the foam material during the vulcanization process of the compression element. Upon activation of the flux, it liquefies, flows to the passivation layer, and removes it.

[0031] In one embodiment of the electrical energy storage device, it has a housing that is at least partially filled with a foam, for example, polyurethane foam, such that the battery cells and the cell contacting system are at least partially surrounded by the foam. The flux is integrated into the foam, and the foam is designed to release the thermally activated flux. The foam serves to stabilize the electrical energy storage device and to mechanically fix the battery cells, the cell contacting system, and other components of the electrical energy storage device. For example, the highly concentrated, non-liquid flux can be integrated into the foaming material and, by filling the housing with foam, positioned, among other places, at the cell connectors.

[0032] The embodiments and advantages presented with reference to the connecting device according to the invention apply accordingly to the device according to the invention. Further features of the invention will become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually.

[0033] The invention will now be explained in more detail with reference to a preferred embodiment and the drawings. The drawings show:

[0034] Fig. 1a, 1b a schematic representation of a connection device according to the prior art with a fuse away from a first fault case and in the first fault case;

[0035] Fig. 2a, 2b a schematic representation of the connection device according to the prior art with the fuse in a second fault case;

[0036] Fig. 3a-3c shows a schematic representation of a connection device according to the invention with a fuse in the second fault case;

[0037] Fig. 4 shows a schematic perspective view of a first embodiment of the connecting device;

[0038] Fig. 5 shows a schematic perspective view of a second embodiment of the connecting device;

[0039] Fig. 6a, 6b shows a schematic perspective view and cross-sectional view of a third embodiment of the connecting device;

[0040] Fig. 7 shows a schematic cross-sectional representation of a fourth embodiment of the connecting device;

[0041] Figs. 8a, 8b show a schematic cross-sectional view of a fifth embodiment of the connecting device; Figs. 9a, 9b show a schematic cross-sectional view and a perspective view of a sixth embodiment of the connecting device; and

[0042] Fig. 10 shows a schematic cross-sectional representation of a seventh embodiment of the connecting device.

[0043] In the figures, identical and functionally equivalent elements are provided with the same reference symbols.

[0044] Fig. 1a shows a highly schematic representation of a connection device T according to the prior art. The connection device T comprises a connecting element 2 made of a metallic material 3, which is surrounded by a passivation layer 4. The connecting element 2 has two contact areas 2a, 2b and a melting area 2c. The melting area 2c here forms a deliberately created fusible link 5, which is formed by a cross-sectional reduction 6 of the connecting element 2. Apart from a fault condition, the connecting element 2 can conduct a current supplied by a current source 7, the current intensity of which lies within a predetermined operating current range. As soon as a low-resistance short circuit occurs, represented here by a short-circuit resistor R1, a fault current in the form of an overcurrent i1 is conducted through the connecting element 2.This overcurrent i1 leads to an initial temperature T1 in the melting area 2c, which causes the melting area 2c to heat up rapidly and "explode," thereby tripping the fuse 5. The connecting element 2 is severed, as shown in Fig. 1b, and the current flow through the connecting element 2 is interrupted.

[0045] Figures 2a and 2b show a "medium-resistance" short circuit, represented by the short-circuit resistance R2, through which a fault current in the form of a short-circuit current i2, lower than the overcurrent i1, is conducted via the connecting element 2. As shown in Figure 2b, the short-circuit current i2 leads to a lower temperature T2 in the melting zone 2c, which results in the melting of the material 3 but not of the passivation layer 4. As shown in Figure 2b, the melting zone 2c deforms due to the molten 3' of the material 3; however, the molten 3' is held in place by the passivation layer 4, so that the fault current i2 continues to flow through the melting zone 2c and the fuse 5 does not trip. To improve the tripping characteristics of the fuse 5, a connecting device 1 is provided, as shown schematically in Figures 3a, 3b, and 3c.The connecting device 1 differs from the connecting device T by an additional flux 8, with which the melting area 2c is coated on both sides. As shown in Fig. 3b, the flux 8 is thermally activated by the fault condition, for example by the melt 3', and removes the passivation layer 4 in a chemical process. Additionally, the flux 8 reduces the surface tension of the melt 3', so that it can retract after the passivation layer 4 is removed, as shown in Fig. 3c. The fusible link 5 is triggered by the flux 8, and the connecting element 2 is severed in the melting area 2c.

[0046] Fig. 4 shows a first embodiment of a connection device 1 in the form of a cell contacting system 9 for an electrical energy storage device. The cell contacting system 9 serves to connect battery cells of the electrical energy storage device. The cell contacting system has a plurality of connecting elements 2, which can be designed as cell connectors 10, in particular of different shapes. The cell connectors 10 can be formed as a stamped and bent part made of material 3 in the form of aluminum, which is surrounded by a passivation layer 4 in the form of an aluminum oxide layer. The cell connector 10 has a first contact area 2a on the positive pole side for contacting a positive cell terminal of one battery cell and a second contact area 2b on the negative pole side for contacting a negative cell terminal of another battery cell.Adjacent to the first contacting area 2a, a holding area 2d is also arranged, via which the cell connector 10 can be attached to a carrier plate of the cell contacting system 9. The cell connector 10 has a protrusion 11 in the area of ​​the cross-sectional reduction 6, which is designed to accommodate deformations of the cell connector 10. In the cross-sectional reduction 6, a further cross-sectional reduction in the form of a melt bridge 12 is formed, which forms the fusible link 5 of the melting area 2c.

[0047] Here, the upper surface of the melting area 2c is covered with a coating 13 containing the flux 8. The coating 13 is in turn covered by a protective layer 14 to prevent a reaction of the flux 8 with the environment of the cell connector 10. In the second embodiment of the connection device 1 according to Fig. 5, in addition to the upper surface, the underside of the melting area 2c is also covered with the coating 13 containing the flux 8. However, the protective layer 14 is only applied to the upper coating 13.

[0048] In the third embodiment of the connecting device 1 according to Fig. 6a (perspective view) and Fig. 6b (sectional view), the carrier plate 15 of the cell contacting system 9 is shown in addition to the cell connector 10. The cell connector 10 is held on the carrier plate by the retaining areas 2d. The carrier plate 15 has openings aligned with or in which the contacting areas 2a, 2b of the cell connector 10 are arranged. The flux 8 is located in the recess 11 of the cross-sectional taper 8 between the underside of the melting area 2c and an upper surface of the carrier plate 15. For example, the carrier plate 15 can be pre-filled with the flux 8 in solid or encapsulated form. Upon activation of the flux 8, it liquefies and can remove the passivation layer 4 in the melting area 2c.

[0049] In a fourth embodiment of the cell contacting system 9 according to Fig. 7, this system additionally features a load distribution plate 16, which is arranged overlapping with an upper surface of the cell connectors 10. A compression element 17 is arranged between the load distribution plate 16 and the upper surface of the cell connectors, which can deform, particularly reversibly, in the direction of the cell connector 10 when the load distribution plate 16 is deformed. The compression element 17 can, for example, be a foam pad made of a foam material 18, such as a soft foam. The flux 8 is arranged here between the upper surface of the cell connector 10, particularly at the apex of the protrusion 11, and an underside of the load distribution plate 16.

[0050] Fig. 8a shows a fifth embodiment of the connecting device 1, in which the compression element 17, which is also shown in a top view in Fig. 8b, is segmented. The compression element 17 has a first segment S1 made of the compressible foam material 18 and a second segment S2 made of flux 8. The compression element 17 is arranged on the cell connector 10 such that the second segment S2 with the flux 8 is located closer to the melting zone 2c than the first segment S1. In the sixth embodiment of the connecting device 1 according to Fig. 9a (sectional view) and Fig. 9b (perspective view without load distribution plate 16), the compression element 17 has two layers L1 and L2, wherein the first layer L1 consists of the foam material 18 and the second layer L2 consists of flux 8.Figure 10 shows a seventh embodiment of the connecting device 1, in which the flux 8 is integrated into pores of the foam material 18 of the compression element 17. For example, the flux 8 can be added to the foam material 18 during the manufacturing of the compression element 17, for example during vulcanization.

Claims

Patent claims 1. Connection device (1) for electrically connecting at least two terminals, comprising: at least one connection element (2) designed for conducting current between the at least two terminals, with at least two contact areas (2a, 2b) for electrical and mechanical connection to the respective terminal, wherein the connection element (2) comprises a metallic material (3) and a passivation layer (4) that forms at least in one fault condition and encloses the metallic material (3), characterized by a flux (8) that can be thermally activated by heat input due to a fault condition, which is designed to remove the passivation layer (4) in the event of a fault condition that melts only the metallic material (3) in a melting area (2c) of the connection element (2) in order to cut through the connection element (2) in the melting area (2c).

2. Connection device (1) according to claim 1, characterized in that the fault condition is a fault current flowing via the at least one connection element (2) and / or heat radiation and / or heat conduction of the component caused by a defect of a component having one of the connections.

3. Connecting device (1) according to claim 1 or 2, characterized in that the at least one connecting element (2) has a cross-sectional reduction (6) in which a fusible link (5) of the connecting element (2) formed by the melting area (2c) is integrated.

4. Connecting device (1) according to claim 3, characterized in that the cross-sectional reduction (6) forms a deformation-absorbing bulge (11), wherein the flux (8) is arranged within the bulge (11).

5. Connecting device (1) according to one of the preceding claims, characterized in that the at least one connecting element (2) has a coating (13) which is arranged at least on one side and at least partially on the at least one connecting element (2) and in which the flux (8) is integrated or which consists of the flux (8).

6. Connecting device (1) according to claim 5, characterized in that the coating (13) is a powder coating, a lacquer and / or a paste.

7. Connecting device (1) according to claim 5 or 6, characterized in that the coating (13) comprising the flux (8) is covered by a protective layer (14).

8. Connecting device (1) according to one of the preceding claims, characterized in that the connecting device (1) has at least one support element which is arranged on the at least one connecting element (2) and which has the flux (8).

9. Connection device (1) according to one of the preceding claims, characterized in that the connection device (1) is designed as a cell contacting system (9) for electrically connecting battery cells of an electrical energy storage device, wherein the at least one connecting element (2) is designed as a cell connector (10) for electrically connecting to each cell pole of the battery cells.

10. Connection device (1) according to claim 9, characterized in that the cell contacting system (9) comprises a carrier plate (15) on which the cell connectors (10) are arranged and attached, wherein the flux (8) is arranged at least partially between a top surface of the carrier plate (15) and a bottom surface of the at least one cell connector (10) and is mechanically connected to the carrier plate (15) and / or the at least one cell connector (10).

11. Connection device (1) according to claim 9 or 10, characterized in that the cell contacting system (9) has a load distribution plate (16) for absorbing force effects on the energy storage device, which is arranged overlapping with the cell connectors (10), wherein the flux (8) is arranged at least partially between a top side of the at least one cell connector (10) and a bottom side of the load distribution plate (16) and is mechanically connected to the load distribution plate (16) and / or the at least one cell connector (10).

12. Connection device (1) according to claim 11, characterized in that the cell contacting system (9) has compression elements (17) which are arranged between the load distribution plate (16) and the cell connectors (10), wherein the compression elements (17) form a carrier for the flux and are designed to release the thermally activated flux for the removal of the passivation layer (4).

13. Connecting device (1) according to claim 12, characterized in that the flux (8) is integrated into pores of a foam material (18) of the compression elements (17).

14. Device comprising at least two components and a connecting device (1) according to one of the preceding claims for connecting the components, wherein the terminals of the components are electrically and mechanically connected to the contacting areas (2a, 2b) of the at least one connecting element (2). are.

15. Device according to claim 14, characterized in that the device is an electrical energy storage device for a motor vehicle, which comprises as its components a plurality of battery cells and which has a connecting device in the form of a cell contacting system.

16. Device according to claim 15, characterized in that the electrical energy storage device has a housing which is at least partially filled with a foam, such that the energy storage cells and the cell contacting system are at least partially surrounded by the foam, wherein the flux is integrated into the foam and the foam is designed to release the thermally activated flux.

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