Connection device with flux

Abstract

The disclosure relates to a connection device (1) for electrically connecting at least two terminals (8, 10) separated by an insulating layer (12), comprising at least one connecting element (2) designed for conducting current between the at least two terminals (8, 10) and having at least two contact areas (4A, 4B) for electrical connection to the respective terminal (8, 10), and a flux (16) which can be thermally activated by fault-induced heat input and is configured to remove a passivation layer that forms on at least one of the terminals (8, 10) in the event of a fault, in particular thermal and / or mechanical damage to the insulating layer (12).

Description

[0001] The disclosure relates to a connecting device for electrically connecting at least two terminals separated by an insulating layer, with at least one connecting element designed for conducting current between the at least two terminals, having at least two contact areas for electrically connecting to the respective terminal. Background of the Revelation

[0002] A high-voltage storage system in a hybrid or electric vehicle is an energy storage system that stores electrical energy in the form of direct current at high voltage. This stored energy is typically used to power at least one of the vehicle's electric motors. These high-voltage storage systems are typically composed of individual battery cells, such as lithium-ion cells, or modules, configured in a battery pack and electrically interconnected by cell connectors. The battery cells are connected to each other via the cell connectors, with their respective cell poles (anode and cathode) separated by an insulating layer.

[0003] In the event of a thermal event in a battery cell, it is crucial for the operational reliability of the battery storage system to prevent thermal propagation, i.e., a progressive thermal event spreading to other battery cells. For this purpose, the connecting elements can have integrated fuses that trigger in the event of a fault and interrupt the current flow between the battery cells. For example, DE 10 2022 124 457 A1 discloses such a fuse, which is designed as a cross-sectional reduction in the cell connector and which melts in the event of a fault current flowing through the cell connector, thus interrupting 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 may not be high enough to produce these effects beyond simply melting the material. For example, 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] In the applicant's unpublished German patent application DE 10 2024 122 065, a connection device with a connecting element designed as a fuse is disclosed. To ensure a sufficiently high fault current for disconnecting the fuse, a thermally activatable flux is arranged in the area of ​​a tapered section of the fuse, which is designed to remove a passivation layer on the tapered section.

[0006] However, with concepts known from the prior art, especially in the case of mechanical and / or thermal damage to the insulation layer between the anode and the cathode of a battery cell in the event of a thermal event, the fault current present at the tapered section may not be sufficient to safely disconnect the fuse. Summary of Revelation

[0007] The tasks and objectives of this disclosure are to eliminate or at least mitigate the disadvantages of the prior art. In particular, it aims to provide a connection device with improved isolation capability, especially in the case of high-resistance, critical insulation faults.

[0008] The tasks and objectives with regard to a generic expansion vessel are solved, as disclosed, by the subject matter of claim 1. The disclosure is thus based on the knowledge that, by applying / arranging a thermally activatable flux, high-resistance insulation faults can be converted into low-resistance insulation faults in order to ensure a high fault current / short-circuit current at the connecting element.

[0009] The connecting device is accordingly equipped, as disclosed, with a flux that can be thermally activated by fault-induced heat input and is designed to remove a passivation layer that forms at at least one of the connections in the event of a fault, in particular thermal and / or mechanical damage to the insulation layer.

[0010] Removing the passivation layer from the terminals promotes fusion of the terminals, which in turn ensures a low-resistance contact between the terminals and consequently a high short-circuit current at the connecting element.

[0011] Advantageous embodiments are claimed in the dependent claims and are explained below.

[0012] In a preferred embodiment, the at least one connecting element can be designed as a metallic fuse with at least one tapered section formed between the at least two contact areas, which melts in the event of a fault and thus separates a connection between the terminals.

[0013] According to a particularly preferred embodiment, the flux can be arranged in the region of the insulation layer. That is, the flux can be located in the immediate vicinity of or in direct contact with the insulation layer. In other words, the flux can be located in the region of the insulation fault to ensure a low-resistance short circuit. Put another way, by the influence of the flux in the region of the insulation fault, fault conditions that would normally produce a high-resistance critical short circuit when the insulation layer melts or is mechanically damaged can be transformed into low-resistance short circuits that are more easily interrupted by a fuse.

[0014] In an advantageous embodiment, the flux can be at least partially surrounded by a protective layer that does not react with the flux, preferably a thermally resistant lacquer or a ceramic coating. This reduces reactions of the flux with its environment, such as foaming, which could potentially have a negative impact on the flux's effectiveness.

[0015] Preferably, the connection device can be configured as a cell contacting system for electrically connecting at least two battery cells of an electrical energy storage device, wherein the at least one connection element is configured as a cell connector for electrically connecting to one cell terminal of each battery cell. It can further be advantageous if a first connection is an anode of a battery cell and a second connection is a cathode of the battery cell. That is, the connection device can be the cell contacting system for connecting the battery cells, in particular the anodes and cathodes of the battery cells, to one another.The connecting element can be designed as the cell connector and preferably includes the integrated fuse, so that in the event of an insulation fault in the insulation layer between the anode and the cathode of a battery cell due to a thermal event of the battery cell, the connection to the next battery cell can be separated by melting the fuse in order to prevent thermal propagation.

[0016] According to an advantageous embodiment, the flux can be arranged over a surface area on the connecting device. In particular, the flux can be arranged on the connecting device such that a surface of the connecting device is substantially completely covered with the flux. For this purpose, the flux can, for example, be sprayed onto the connecting device. In an alternative embodiment, the flux is integrated into or incorporated into a surface layer of the connecting device. This can be done, in particular, in the form of cavities or pores, from which the flux is released upon heating. This embodiment offers the technical advantage that the flux is only activated when needed, namely during the heating process, which enables a controlled and efficient release.Furthermore, it is conceivable to apply the flux to the joining device using an immersion process. In this process, the joining device is immersed in a flux bath, resulting in particularly uniform and complete surface wetting. This method is especially suitable for complex geometries of the joining device. It is also possible to apply the flux to the joining 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 joining device. The planar application of the flux ensures that it is present precisely where it is needed, namely in the area of ​​the insulating layer.Furthermore, applying the flux over a larger area, compared to applying it at specific points, allows for a reduction in the required amount of flux, which offers both economic and ecological advantages. Additionally, applying the flux over a larger area is easier to implement mechanically and consequently results in lower production costs. Brief description of the characters

[0017] The disclosure is explained in more detail below with reference to preferred embodiments and the figures. These show: Fig. 1 a schematic view of a connection device as disclosed according to a preferred embodiment; Fig. 2 a schematic view of the connection device according to the preferred embodiment in a fault condition; and Fig. 3 A schematic view of the connecting device according to a modification of the preferred embodiment.

[0018] The figures are schematic and serve only to aid in understanding the revelation. Identical elements are marked with the same reference symbols. Detailed description of preferred embodiments

[0019] Fig. Figure 1 schematically shows a connecting device 1 according to a preferred embodiment. The connecting device 1 has a connecting element 2 with two contact areas 4A, 4B, between which a tapered section 6 is arranged.

[0020] One contact area 4A is electrically connected to a first terminal 8, whereas the other contact area 4B is electrically connected to a second terminal 10. The first terminal 8 and the second terminal 10 are separated from each other by an insulating layer 12, so that current from one terminal to the other cannot flow through either terminal. Fig. 1 schematically represented power source 14 via the connecting element 2 between the first terminal 8 and the second terminal 10.

[0021] As in Fig. As can be seen in 1, a flux 16 is arranged in the area of ​​the insulation layer 12, which in the case of a Fig. Figure 2 shows mechanical and / or thermal damage to the insulation layer 12, and a passivation layer is removed at the first terminal 8 and / or the second terminal 10. The flux 16 is therefore located in the area of ​​an insulation fault, as shown in the disclosure.

[0022] The aforementioned removal of the passivation layer promotes the fusion of the first terminal 8 and the second terminal 10, which ensures a high short-circuit current / fault current at the connecting element 2. Due to this high short-circuit current, the tapered section 6 can melt.

[0023] Fig.Figure 3 shows a modification of the connection device 1 according to the preferred embodiment. The connection device 1 is configured as a cell contacting system 18, which connects at least two battery cells 20 of a battery storage device. The connection element 2 is further configured as a cell connector 22 with an integrated fuse 24. The cell connector 22 electrically connects the at least two battery cells 20. In particular, the cell connector 22 connects an anode 26 and a cathode 28 of one battery cell 20 to another battery cell. The anode 26 is a first terminal 8, whereas the cathode 28 is a second terminal 10.

[0024] The anode 26 and the cathode 28 are separated from each other by the insulating layer 12. Furthermore, as disclosed, the flux 16 is arranged in the region of the insulating layer 12.

[0025] If, due to a thermal event in battery cell 20, the insulation layer 12 is damaged, the flux 16 removes the passivation layer, allowing the anode 26 and the cathode 28 to fuse. Because of this low-resistance contact, a high short-circuit current is present at the cell connector 22, sufficient to trip the fuse 24, which in turn inhibits thermal propagation, i.e., the spread of the thermal event to the other battery cells. Reference symbol list 1 Connection device 2 Connecting element 4A, 4B Contact area 6. Rejuvenation section 8 first connection 10 second connection 12 Insulation layer 14 Power source 16 fluxes 18 cell contacting system 20 battery cells 22 cell connectors 24 fuses 26 Anode 28 Cathode QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2022 124 457 A1

[0003] DE 10 2024 122 065

[0005]

Claims

[1] Connection device (1) for electrically connecting at least two terminals (8, 10) separated by an insulating layer (12), with at least one connecting element (2) designed for conducting current between the at least two terminals (8, 10) with at least two contact areas (4A, 4B) for electrical connection to the respective terminal (8, 10), characterized by a flux (16) which can be thermally activated by fault-induced heat input and which is designed to remove a passivation layer which forms at at least one of the terminals (8, 10) in the event of a fault, in particular thermal and / or mechanical damage to the insulation layer (12). [2] Connecting device (1) according to claim 1, characterized by, that the at least one connecting element (2) is designed as a metallic fuse with at least one tapered section (6) formed between the at least two contact areas (4A, 4B), which melts in the event of a fault and thus separates a connection between the terminals (8, 10). [3] Connecting device (1) according to claim 1 or 2, characterized by , that the flux (16) is arranged in the area of ​​the insulating layer (12). [4] Connecting device (1) according to any one of the preceding claims 1 to 3, characterized by that the flux (16) is at least partially surrounded by a protective layer, preferably a thermally resistant varnish or a ceramic coating. [5] Connecting device (1) according to any one of the preceding claims 1 to 4, characterized by, that the connecting device (1) is designed as a cell contacting system (18) for electrically connecting at least two battery cells (20) of an electrical energy storage device, wherein the at least one connecting element (2) is designed as a cell connector (22) for electrically connecting to each cell pole (26, 28) of the battery cells (20). [6] Connecting device (1) according to claim 5, characterized by , that a first terminal (8) is an anode (26) of a battery cell (20) and a second terminal (10) is a cathode (28) of the battery cell (20).

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