Device for material testing

Abstract

The invention relates to a device (100) for material testing by means of a hot gas mass flow (310), comprising a test chamber (110) with a test specimen holder (120) which is designed and configured for receiving and holding a test specimen (400), a hot gas mass flow source and a measuring device (190), wherein the hot gas mass flow source is a hot gas mass flow generator (300) which is designed and configured to generate a hot gas mass flow (310) and to direct it in a beam direction onto a test specimen (400), wherein at least one characteristic parameter from a group of characteristic parameters, comprising beam duration, beam temperature, pressure pulse, pulse curve, particle size and particle quantity, is predefinable and / or adjustable and / or controllable.

Description

[0001] The invention relates to a device for material testing, in particular for simulating the stress on battery materials by a hot gas mass flow, as occurs during thermal runaway of battery cells.

[0002] Lithium-ion batteries for long-range electric vehicles have a very high cell density. External influences or a fault in a single battery cell can lead to thermal runaway. In this process, the battery cell is destroyed by exothermic reactions, releasing a large amount of energy. This can then trigger a chain reaction from cell to cell, affecting the entire battery pack. This process releases extremely large amounts of energy and substances that are harmful to health and the environment.

[0003] DE 10 2024 105 374 A1 discloses a test device for testing the thermal resistance of battery components for a high-voltage battery, wherein the test device has an enclosure for receiving at least one battery cell and the enclosure is bounded by a wall element with a holding device for holding the battery component, which exposes the battery component to the enclosure. During operation of the test device, a battery component to be tested is inserted into the holding device of the test device and at least one battery cell is arranged in the enclosure of the test device, then thermal runaway of the battery cell is triggered and the battery component is thereby exposed to the influence of thermal runaway.

[0004] The invention is based on the objective of providing a device that makes it possible to carry out material tests on battery materials and battery components as well as other vehicle components which are exposed to a hot gas mass flow in the event of thermal propagation, also known as a thermal propagation event, wherein the material testing is to take place under precisely definable and repeatable test conditions.

[0005] The problem is solved according to the invention by a device having the features of the characterizing part of claim 1.

[0006] Advantageous embodiments of the invention are the subject of the dependent claims.

[0007] In a device for material testing by means of a hot gas mass flow, comprising a test chamber with a test specimen holder designed and configured for receiving and holding a test specimen, a hot gas mass flow source and a measuring device, it is proposed according to the invention that the hot gas mass flow source is a hot gas mass flow generator designed and configured to generate a hot gas mass flow and direct it in a beam direction onto a test specimen, wherein at least one characteristic parameter from a group of characteristic parameters, including beam duration, beam temperature, pressure pulse, pulse curve, particle size and particle quantity, is predefinable and / or adjustable and / or controllable.

[0008] The key element for the test setup is the hot gas mass flow. Its generation must be selected according to the specific battery cell being simulated. The hot gas mass flow generator can, for example, comprise a solids booster and / or a turbine and / or a particle source. To generate a directed hot gas mass flow, the hot gas mass flow generator can, for example, have a nozzle, in particular a Laval nozzle. In one embodiment, the hot gas mass flow generator can be arranged with an adjustable distance relative to the test specimen holder. The distance between the hot gas mass flow generator and the test specimen can preferably be variable and continuously adjustable, for example, within a range of 50 mm to 200 mm.

[0009] The device according to the invention forms a test rig for testing materials with regard to their suitability or behavior when directly exposed during a thermal propagation event in a battery, when a hot gas mass flow from one or more defective battery cells radiates directly or indirectly onto the material to be tested, by simulating this stress on the test specimen with precisely predefinable parameters in a repeatable manner.

[0010] The measuring equipment can include, for example, at least one force sensor, one mechanical sensor for deformation measurements, one camera, one thermal imaging camera, one pyrometer, one gas chromatograph, one mass spectrometer, and so on. The test bench, through this measuring equipment, enables the comprehensive recording of test data for characterizing and determining the suitability of the tested material. This allows materials to be pre-validated cost-effectively with regard to their suitability in batteries, as neither expensive battery cells nor complete battery test setups are required.

[0011] In one configuration, the test specimen holder can be designed and configured to arrange two or more test specimens one behind the other in the direction of the beam. This gives the test rig the option of expansion, for example, to simulate a layer of vehicle flooring. This allows the complex interactions in the battery environment during a thermal propagation event to be simulated, for example, regarding cathodic dip coating (KTL) fires or the suitability of NVH materials.

[0012] In one embodiment, a deflection device may be arranged behind the test specimen(s) in the direction of the beam. This deflection device is designed and configured to deflect a hot gas mass flow directed at the specimen(s). In a further development, the deflection device may comprise a wedge, a pyramid, or a cone. In the event of a burn-through of the test specimen, the deflection device serves to deflect the hot gas mass flow so that the measuring device, for example, a force sensor on, in, or under the floor of the test chamber, does not detect a second impulse, thus enabling a clear temporal classification of the burn-through based on the measurement data. When using the device to simulate the vehicle floor, the deflection device can be removed.

[0013] In one embodiment, the device may include a pivoting mechanism designed and configured to pivot the test chamber about a horizontal axis. The pivoting, and optionally the locking of the test chamber in a pivoted position, can be stepless, for example. In a further embodiment, the pivoting mechanism may alternatively or additionally be designed and configured to lock the test chamber in predefinable pivoted positions.

[0014] In one embodiment, a disturbance geometry holder may be arranged in the test chamber. This holder is designed and configured to receive and hold a disturbance geometry in the beam direction in front of the test specimen(s). Without the use of a disturbance geometry, the test specimen is irradiated directly. Tests are conceivable in which, for example, a standardized wedge or a project- or component-specific disturbance geometry, such as a busbar or the fragment of an open rupture membrane, is held in the hot gas mass flow as the disturbance geometry, so that the test specimen is indirectly irradiated.

[0015] In one embodiment, the test chamber can be arranged within a protective chamber equipped with a ventilation system for smoke extraction, thus preventing negative effects on, for example, optical sensors and cameras. Controlled environmental conditions created by such a protective enclosure during testing enable analyses using gas chromatographs or mass spectrometers. For test setups specifically designed to induce gas accumulation, such as during a cathodic dip coating (KTL) fire, the ventilation can be deactivated. In a further development, the protective chamber can be equipped with an air conditioning system for controlling temperature and / or humidity. Temperature and humidity control ensures the comparability and stability of the tests. Furthermore, controlled humidity helps to reduce smoke generation.

[0016] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0017] This shows: Fig. 1 schematically a first embodiment of the device, Fig. 2 schematically a second embodiment of the device, Fig. 3 schematically a third embodiment of the device, Fig. 4 schematically diverse configurations, Fig. 5 schematically a first embodiment of the hot gas mass flow generator, Fig. 6 schematically a second embodiment of the hot gas mass flow generator, Fig. 7 schematically a fourth embodiment of the device, Fig. 8 schematically a fifth embodiment of the device, Fig. 9 schematically a sixth embodiment of the device,

[0018] Corresponding parts are marked with the same reference symbols in all figures.

[0019] In Fig. Figure 1 shows a first embodiment of the device 100 according to the invention. A test specimen holder 120 is arranged in a test chamber 110, on which a test specimen 400 is held. A hot gas mass flow generator 300 is arranged above the test specimen 400, which is designed to generate a hot gas mass flow 310 and which directs this hot gas mass flow 310 onto the test specimen 400. A disturbance geometry support 170 is arranged above the test specimen 400.

[0020] The test specimen holder 120 is supported by a force sensor 420, which, along with two cameras 410 and a measuring probe 430, belongs to a measuring device 190. A viewing window 200 is also arranged in the test specimen holder 120, through which the underside of the test specimen 400 can be viewed.

[0021] The exemplary embodiment according to Fig. 2 differs from that of the Fig. 1. The test specimen holder 120 is designed to hold two test specimens 400. A total of four cameras 410 are directed through appropriately arranged viewing windows 200 at the top and bottom surfaces of the two test specimens 400. In the first illustration, the upper test specimen 400 is exposed to the hot gas mass flow 310. In the second illustration, the hot gas mass flow 310 has destroyed the upper test specimen 400, so that the hot gas mass flow 310 now acts on the lower test specimen 400.

[0022] In the embodiment according to Fig. Figure 3 shows that the device 100 has a pivoting mechanism 140 which makes it possible to pivot the test chamber 110 about a horizontal axis 150 and to fix it at different pivoting positions by means of a plurality of positioning aids 160 in order to simulate different jet directions of the hot gas mass flow 310. The figures show, by way of example, how the test chamber 110 is positioned in its initial position, i.e., at a pivot angle of 0°, as well as at pivot angles of 90°, 135° and 180°.

[0023] In Fig. Figure 4 shows different configurations in which, in Figure A, no disturbance geometry 180 is attached to the disturbance geometry holder 170 in the test chamber 110, in Figure B a wedge-shaped disturbance geometry 180 and in Figure C a disturbance geometry 180 in the form of a burst disc is arranged, and how the disturbance geometry holder 170 can be moved within the test chamber 110 in order to move the disturbance geometry 180 into the hot gas mass flow 310.

[0024] In Fig. Figure 5 shows a first hot gas mass flow generator 300, in which a fuel 330 is arranged in a housing 320, which is ignited to generate a (not shown here) hot gas mass flow 310 and the resulting hot gas mass flow 310 is expelled downwards through a nozzle 340 from the housing 320.

[0025] In Fig. Figure 6 shows a second hot gas mass flow generator 300, in which a turbine 350 is arranged in a housing 320, which generates a (not shown here) hot gas flow which is enriched with particles at the lower end of the housing 320 by a particle feeder 360.

[0026] In the exemplary embodiment of the Fig. 7 Below the test specimen 400 is a deflecting device 130 through which the hot gas mass flow 310 is diverted to the sides.

[0027] In the exemplary embodiment of the Fig. 8 The measuring device 190 comprises a plurality of measuring sensors 430, which are arranged at different positions within the test chamber 110.

[0028] In Fig. Figure 9 shows an embodiment in which the test chamber 110 is arranged in a protective chamber 210 which has a ventilation device 220. Reference symbol list 100 Device 110 Test chamber 120 candidates 130 Deflection device 140 Swivel device 150 horizontal axis 160 Positioning aid 170 Disturbance geometry bracket 180 Disturbance geometry 190 Measuring device 200 viewing windows 210 Protective chamber 220 Ventilation unit 300 Hot gas mass flow generator 310 Hot gas mass flow 320 case 330 Fuel 340 nozzle 350 Turbine 360 particle feed 400 examinees 410 camera 420 force sensor 430 sensors 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 2024 105 374 A1

[0003]

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