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DE-102025112484-A1 - Connection device with flux

DE102025112484A1DE 102025112484 A1DE102025112484 A1DE 102025112484A1DE-102025112484-A1

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).

Inventors

  • Jochen Brandmaier
  • Joseph Endres
  • Philipp Krost
  • Felix Laasch
  • Sascha Zimmermann
  • Franz Fuchs
  • Oliver Bichi Zhang

Assignees

  • BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT

Dates

Publication Date
20260513
Application Date
20250331
Priority Date
20241113

Claims (6)

  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) and having 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 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).
  2. Connecting device (1) according to Claim 1 , characterized in 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 in that the flux (16) is arranged in the area of the insulating layer (12).
  4. Connecting device (1) according to one of the preceding Claims 1 until 3 , characterized in 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 one of the preceding Claims 1 until 4 , characterized in 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 in 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).

Description

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 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. 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, the DE 10 2022 124 457 A1 Such a fuse, which is designed as a cross-sectional reduction in the cell connector and which, in the event of a fault current flowing through the cell connector, is intended to melt to interrupt the current flow between the battery cells. 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. In the as yet unpublished German patent application DE 10 2024 122 065 The applicant discloses a connection device with a connecting element designed as a fuse. 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. 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 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. 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. 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. 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. Advantageous embodiments are claimed in the dependent claims and are explained below. 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. 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