DE-102024133120-A1 - Method for tripping a fuse in a high-voltage storage system

Abstract

The invention relates to a method (100) for triggering a safety device in a high-voltage storage device (10), wherein a number of battery cells (12) of the high-voltage storage device (10) are electrically connected by means of a cell contacting device (11) and the cell contacting device (11) has a number of safety devices (13), comprising steps of operating the high-voltage storage device (10); detecting a safety-relevant event at at least one battery cell (12); and triggering at least one safety device.

Inventors

• Felix Laasch
• Kevin Czyrka
• Franz Fuchs
• Sascha Zimmermann

Assignees

• BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT

Dates

Publication Date

20260513

Application Date

20241113

Claims (11)

1. Method (100) for tripping a safety device in a high-voltage storage device (10), wherein a number of battery cells (12) of the high-voltage storage device (10) are electrically connected by means of a cell contacting device (11) and the cell contacting device (11) has a number of safety devices (13), comprising the following steps: a) operating the high-voltage storage device (10); b) detecting a safety-related event at at least one battery cell (12); c) activating a superimposed current flow (I _ü ) to trip at least one safety device (13); and d) tripping at least one safety device (13) by means of the superimposed current flow (I_ü ).
2. Method (100) according to the preceding claim, wherein the superimposed current flow (I ü ) is activated depending on a predetermined criterion.
3. Method (100) according to the preceding claim, wherein the predetermined criterion comprises a predetermined time interval and/or a voltage threshold.
4. Method (100) according to one of the preceding claims, wherein the superimposed current flow (I ü ) is adjustable.
5. Method (100) according to one of the preceding claims, wherein the superimposed current flow (I ü ) is applied in a time-varying manner.
6. Method (100) according to one of the preceding claims, wherein the superimposed current flow (I ü ) is adjusted such that safety devices (13) of a predetermined assembly (14) of the affected battery cell (12) are disconnected.
7. Method (100) according to one of the preceding claims, wherein the assembly (14) comprises battery cells (12) connected in parallel.
8. Method (100) according to one of the preceding claims, wherein the superimposed current flow (I ü ) is generated by means of a battery management system (16).
9. Method (100) according to one of the preceding claims, wherein the superimposed current flow (I ü ) is generated by means of a power electronics (17) of an electric machine (18) connected to the high-voltage storage device (10).
10. Method (100) according to one of the preceding claims, wherein an unaffected portion (20) of the high-voltage storage device (10) is separated.
11. Method (100) according to one of the preceding claims, wherein the high-voltage storage device (10) is brought into a safe state after a predetermined period of time.

Description

The invention relates to a method for triggering a safety device in a high-voltage storage system, wherein a number of battery cells of the high-voltage storage system are electrically connected by means of a cell contacting device and the cell contacting device has a number of safety devices, comprising steps of operating the energy storage system; detecting a safety-relevant event at at least one battery cell; and triggering at least one safety device. High-voltage storage devices, also known as traction batteries or accumulators, are used to provide electrical energy for powering electric motors in motor vehicles. These high-voltage storage devices typically consist of an arrangement of battery cells connected in parallel and series via a contacting device, all housed within a casing. This contacting device typically incorporates safety features to protect against overload, short circuits, and/or thermal problems. For example, a thermal event or short circuit in a battery cell can create a short-circuit resistance that, compared to normal operating currents, can generate reduced fault currents, especially from parallel-connected battery cells, which cannot be isolated by the usual safety devices. These fault currents, however, can be sufficient to release a safety-relevant amount of heat at the fault location. Against this background, an object of the invention is to improve a method for tripping a fuse in a high-voltage storage system. In particular, a method for tripping a fuse in an energy storage system is to be improved in such a way as to enable increased safety, especially in the event of damage and/or a fault in a battery cell of the high-voltage storage system. This problem is solved by a method for tripping a fuse in a high-voltage storage device with the features of claim 1. The dependent claims relate to advantageous embodiments of the invention. According to a first aspect, a method for triggering a safety device in a high-voltage storage device, in particular for a motor vehicle, is specified, comprising steps of operating the high-voltage storage device; detecting a safety-relevant event on at least one battery cell; activating a superimposed current flow to trigger at least one safety device; and triggering at least one safety device by means of the superimposed current flow. By triggering at least one safety device, a current flow or current path and/or, in particular, fault currents from neighboring cells of the affected battery cell can be interrupted, for example, to prevent dangerous heat build-up. This can prevent or even stop a safety-critical progression of the malfunction. A high-voltage storage system is, in particular, an energy storage device or traction battery for a motor vehicle, comprising multiple battery cells. The housing of the high-voltage storage system defines an interior space in which the battery cells or battery cell arrays are housed or arranged. Cylindrical or prismatic battery cells are primarily used, which can be provided in a cell pack. The cell contacting device is designed to contact the battery cells at their electrical poles and to enable parallel and series connection of these battery cells in a cell assembly. The cell contacting device can be designed as a single unit or in multiple parts to electrically connect a large number of battery cells, or it can have (several) individual contact elements that are electrically and/or mechanically connectable or already connected to one another. The respective contact element or cell contacting device can be arranged on the end face of the respective battery cell of the high-voltage storage system or its cell terminal and, in particular, can be designed as an electrically conductive track, strip, or sheet metal that is designed to connect the positive and/or negative contacts or poles of battery cells, especially across individual cells and/or cell rows. The cell contacting device includes a predetermined number of identical or different locking devices. Such a safety device can, for example, be designed as a thermally triggered fuse and/or a fuse, whereby the safety devices can be arranged, for example, in a one-to-one correspondence to the battery cells and/or as string fuses. Of course, other arrangements and/or designs of the safety devices are also conceivable. When operating the high-voltage storage system, the battery cells are charged or discharged to power an electric machine and/or at least one vehicle component, resulting in a primary current flow within the high-voltage storage system, the battery cells, and the cell contacting device. A safety-relevant event, such as thermal runaway and/or a short circuit in an affected battery cell, can be detected, for example, by at least one sensor and/or at least one pressure, voltage, and/or temperature measurement within the high-voltage storage system. Upon detection of such a safety-relevant event or fault in a battery cell, a superimposed current flow is