Device for measuring a gas mixture

Abstract

The present invention relates to a device (100) for measuring a gas mixture. The device (100) according to the invention comprises a gas sensor (110) for measuring the gas mixture. The gas sensor (110) has a sensor element (120) designed to come into contact with the gas mixture for measuring the same. The device according to the invention further comprises a gas supply path (114) designed to supply the gas mixture to the sensor element (120) of the gas sensor (110), and a porous filter element (130) arranged in the gas supply path (114) and designed to prevent gas components that are located in the gas mixture and that interfere with the measurement from reaching the sensor element (120). The porous filter element (130) is made of foam.

Description

[0001] 202401746

[0002] 1

[0003] Description

[0004] Device for measuring a gas mixture

[0005] The present invention relates to a device for measuring a gas mixture, in particular a gas mixture within a vehicle battery, especially for detecting a thermal runaway of a battery cell of the vehicle battery arranged in a battery housing.

[0006] The sensor elements of gas sensors, which can detect the concentration of certain components in gas mixtures, are sensitive and susceptible to contaminants such as particles, dust, electrolytes, and / or water. Such impurities can passivate, poison, impair, or even completely disable the gas sensor.

[0007] It is known from the prior art to provide filters and / or membranes as measures to prevent such contamination on so-called micromechanical systems (MEMS) with a suitable open mesh size, acting as a mechanical sieve against the expected contamination. Combinations of filter layers are also used.

[0008] From US 7479255 B2 a gas sensor is known which has a sensor element, a resistance heating device and a water-repellent filter which is arranged at the housing inlet of the sensor.

[0009] Further state of the art is represented by WO 2024 / 216967 A1 , CN 220585292 U, US 8 196448 B2 and US 8821 797 B2.

[0010] In view of the prior art, it is an object of the present invention to provide a device in which the risk of contamination of the sensor element is at least partially reduced and202401746

[0011] 2

[0012] which can reliably deliver accurate measurement results even during long operating times.

[0013] This problem is solved by a device according to claim 1. Advantageous embodiments are specified in the dependent claims.

[0014] The present invention is essentially based on the idea of ​​providing a porous foam filter element in a gas supply path that feeds a gas mixture to be measured to a sensor element of a gas sensor. By providing the porous foam filter element, the sensor element can be protected from adverse components present in the gas mixture being measured, such as water and / or electrolytes that can be generated during thermal runaway of a vehicle battery. These adverse components in the gas mixture can be captured and removed by the porous foam filter element. In particular, the porous filter element can provide condensation surfaces for these components.

[0015] According to a first aspect of the present invention, a device for measuring a gas mixture is disclosed. The device according to the invention comprises a gas sensor for measuring the gas mixture, which has a sensor element configured to come into contact with the gas mixture for measurement, a gas supply path configured to supply the gas mixture to the sensor element of the gas sensor, and a porous filter element arranged in the gas supply path, which is configured to prevent gas components present in the gas mixture that would interfere with the measurement from reaching the sensor element. The porous filter element consists of a foam, preferably an open-cell or open-pore foam.

[0016] In an advantageous embodiment of the device according to the invention, the porous filter element has a thickness in the range of approximately 3 mm to approximately 5 mm. 202401746

[0017] 3

[0018] Furthermore, it may be preferred that the porous filter element has a pore count in the range of approximately 10 ppi and approximately 90 ppi [ppi = pore count per inch].

[0019] Preferably, the porous filter element is designed to dissipate the heat from the electrolyte and / or water that condenses on it. When the gas or gas mixture flows through the porous filter element, it impacts the pore walls and is at least partially deflected. Simultaneously, the gas mixture interacts with the pore surfaces, releasing energy and causing it to condense, at least partially. The resulting condensate cannot pass through the diffusion membrane and is thus kept away from the sensor element.

[0020] In a further preferred embodiment, the device according to the invention also comprises a diffusion membrane arranged in the gas supply path, which is configured to at least partially control the gas supply of the gas mixture to be measured to the sensor element such that the gas mixture diffuses through the diffusion membrane. Preferably, the diffusion membrane is arranged downstream of the porous filter element.

[0021] In a particularly preferred embodiment of the device according to the invention, the gas sensor has a sensor housing in which the sensor element is arranged. The gas supply path extends from the interior of the battery housing into the sensor housing and up to the sensor element. The porous filter element is at least partially arranged within the sensor housing.

[0022] In an alternative embodiment of the device according to the invention, the gas sensor has a sensor housing in which the sensor element is arranged. The gas supply path extends from the interior of the battery housing through an opening provided in the sensor housing into the interior of the 202401746

[0023] 4

[0024] Sensor housing. The porous filter element is at least partially located in the opening in the sensor housing.

[0025] In a further alternative embodiment, the device according to the invention comprises a sensor cell arranged in the battery housing, in which the gas sensor is arranged. The gas supply path extends from the interior of the battery housing through an opening provided in the sensor cell into the interior of the sensor cell. The porous filter element is at least partially arranged in the opening in the sensor cell.

[0026] Preferably, the porous filter element is made of sintered metal. A filter element made of sintered metal offers high mechanical stability and temperature resistance, which is particularly advantageous in environments with elevated temperatures (e.g., during thermal runaway of a battery). Furthermore, sintered metal is corrosion- and chemically resistant, allowing it to withstand aggressive components of the gas mixture (such as electrolyte vapors) and enabling a long service life without degradation. The finely porous structure of the sintered metal allows for the effective separation of contaminants: particles and liquid droplets (water, electrolyte) are retained, while the desired sample gas flow can pass through unimpeded.The metallic porous matrix also acts as a heat conductor and condensation surface – it dissipates the heat from the flowing gas mixture and thus promotes the condensation of water vapor or electrolyte aerosols on the pore walls. The resulting condensate is bound within the filter element and kept away from the sensor element, reliably protecting the measuring sensor from contamination. Furthermore, a fine-pored sintered metal filter can function as a flame arrestor due to its metallic structure, which increases safety when dealing with hydrogen-containing gases (preventing flames or sparks from passing through the sensor). Overall, a filter element made of sintered metal contributes to ensuring the service life and measuring accuracy of the gas sensor, even over extended periods of operation. 202401746.

[0027] 5

[0028] Alternatively or additionally, the porous filter element is designed as a metal mesh with a mesh size ranging from approximately 5 pm to approximately 50 pm. A filter element in the form of a metal mesh offers the advantage of a precisely defined filter fineness. The example mesh size mentioned is small enough to trap fine particles and droplets in the gas (acting like a sieve for impurities), yet large enough to barely impede the gas flow. This ensures that harmful aerosols or dust particles do not reach the sensor element, while the target gas (e.g.,

[0029] Hydrogen can diffuse to the sensor almost instantaneously, ensuring accurate and rapid measurement results. A metal mesh is also very robust and durable: it tolerates temperature fluctuations and aggressive gas components better than polymer-based filter membranes and retains its structure and filtering effect over the long term. The use of stainless steel or other corrosion-resistant metal mesh ensures that no corrosion or wear enlarges or clogs the openings, maintaining stable filter performance over time. At the same time, a thin metal mesh can be easily integrated into the gas supply path (e.g., at the sensor housing inlet) and forms an initial barrier against contamination without requiring much installation space. Overall, a filter element designed as a metal mesh protects the sensor from contamination without excessively restricting gas exchange or complicating the design.

[0030] Furthermore, the porous filter element can be designed as metal spheres with a diameter ranging from approximately 5 pm to approximately 50 pm. A filter element composed of many small metal spheres utilizes a three-dimensional depth filter structure with a high surface area. The fine metal spheres form a branched, porous flow path in which the gas mixture comes into intensive contact with the metal surfaces. This has several advantages: Contaminants are separated extremely effectively because particles and liquid droplets encounter a surface more frequently as they pass through the sphere pack and adhere to it or condense. The metal spheres function similarly to a metallic sponge—they conduct heat away from the gas and thus promote the condensation of water vapor or electrolyte mist.

[0031] 6

[0032] Filter bed. The resulting condensate is retained within this sphere packing, preventing liquid electrolyte or water from reaching the sensor element. Ultimately, filter elements designed as metal spheres ensure that the gas sensor is protected even under demanding conditions (e.g., electrolyte splashes or condensation from battery failures) and can deliver consistently precise measurements.

[0033] With a preferred arrangement of the metal spheres between two metal grids (which hold the spheres in place), the filter element remains dimensionally stable and vibration-resistant. Simultaneously, by selecting the sphere diameters and packing density, the pore size and permeability can be precisely controlled, similar to a sintered filter, but with potentially simpler manufacturing or replacement. The multitude of contact points and pore spaces gives the filter a high capacity for contaminants, allowing it to remain effective over extended periods without premature clogging.

[0034] Further features and the purpose of the invention will become apparent to the person skilled in the art by carrying out the present teaching and examining the drawings, in which:

[0035] Fig. 1 shows a schematic sectional view through a device according to the invention in a first exemplary embodiment,

[0036] Fig. 2 shows a schematic sectional view through a device according to the invention in a further exemplary embodiment, and

[0037] Fig. 3 shows a schematic sectional view through a device according to the invention in a further exemplary embodiment.

[0038] Elements of the same construction or function are assigned the same reference symbols across all figures. 202401746

[0039] 7

[0040] Within the scope of this disclosure, the term "foam" encompasses an artificially produced material with a cellular structure. The individual cells are preferably hollow and typically filled with air, making foams lightweight and consequently low-density. Almost all plastics, such as polystyrene, PVC, and polyurethane foam, are suitable for the production of such foams. Furthermore, foams are materials with open cells distributed throughout their entire mass. An important parameter of the foam is its tortuosity, which describes the degree of twisting of the pathways within the pores of the porous filter element.

[0041] Fig. 1 shows a schematic sectional view through a device 100 according to a first exemplary embodiment of the invention. The device 100 comprises a gas sensor 110, which has a sensor element 120 configured to come into contact with the gas mixture for measurement. The sensor element 120 is equipped with electronic components and configured to detect the concentration of a predetermined gas component, such as hydrogen, in the gas mixture to be measured. The measuring principle of the sensor element 120 is based, for example, on the thermal conductivity measuring principle known from the prior art. For the sake of simplicity and clarity, elements and components not essential to the invention, such as a circuit board and electrical wiring, are not shown in Fig. 1. However, it is self-evident to those skilled in the art that the device 100 of Fig.1 such elements and components that are necessary for a proper measuring principle.

[0042] The gas sensor 110 of Fig. 1 has a sensor housing 112 in which the sensor element 120 is arranged. An opening 113 is provided in the sensor housing 112, through which a gas guidance path 114 extends from the outside of the sensor housing 112 to the sensor element 120. [The202401746]

[0043] 8

[0044] Gas guidance path 114 is designed to guide or direct the gas mixture to be measured from the outside to the sensor element 120.

[0045] In the gas supply path 114 of the device 100 of Fig. 1, a diffusion membrane 140 is provided, which is designed to at least partially control the gas supply of the gas mixture to be measured to the sensor element 120 such that the gas mixture diffuses through the diffusion membrane 140. Consequently, the diffusion membrane 140 prevents the gas mixture to be measured from flowing through it, which can lead to measurement inaccuracies. In addition, the diffusion membrane prevents any solids present in the gas mixture, such as dust and particles, from reaching the sensor element 120.

[0046] The diffusion membrane 140, for example, is made of polytetrafluoroethylene (PTFE) and can be multi-layered. Because the diffusion membrane 140 facilitates diffusion, it ensures that the sensor element 120 is not directly exposed to the flow, allowing gas exchange to act on the sensor element 120 in an undirected manner. If a flow were present at the sensor element 120, this could create cross-sensitivity, negatively impacting measurement accuracy.

[0047] The device 100 according to the invention, shown in Fig. 1, further comprises a porous filter element 130 arranged in the gas supply path 114, which is designed to prevent components present in the gas mixture and interfering with the measurement of the gas mixture, such as electrolyte and / or water, from reaching the sensor element 120. According to the embodiment shown in Fig. 1, the porous filter element 130 is arranged within the sensor housing 112.

[0048] Preferably, the porous filter element 130 is arranged upstream of the diffusion membrane 140.

[0049] The porous filter element 130 consists of a foam, preferably an open-cell or open-pore foam. The porous filter element 130 is designed to capture contaminants in the gas mixture, such as electrolyte and / or water, and to drain them away in such a way that these 202401746

[0050] 9

[0051] Contaminants are prevented from reaching the sensor element 120. The main function of the porous foam filter element 130 is to at least partially convert interfering gas components present in the predominantly warm gas mixture into the liquid phase and then drain these interfering gas components, such as water and / or electrolyte, as condensate. This protects the sensor element 120 from these gas components. The porous filter element 130 is thicker than the diffusion membrane 140 and preferably has a thickness in the range of approximately 3 mm to approximately 5 mm. Furthermore, it is preferable for the porous filter element 130 to have a pore count in the range of approximately 10 ppi to 90 ppi.

[0052] Fig. 2 also shows a sectional view through a device 100 according to the invention in a further exemplary embodiment. The device 100 of Fig. 2 differs from the device 100 of Fig. 1 in that the porous filter element 130 is arranged in the opening 113 of the sensor housing 112.

[0053] Fig. 3 shows a schematic sectional view through a device 100 according to a further exemplary embodiment of the invention. The device 100 of Fig. 3 is integrated into a battery arrangement 200 for a vehicle, which has a battery housing 212 and at least one battery cell 210 arranged therein. The device 100 of Fig. 3 comprises a sensor cell 230 arranged in the battery housing 212, in which the gas sensor 110 is arranged. The gas supply path 114 extends from the interior of the battery housing 212 through an opening 232 provided in the sensor cell 230 into the interior of the sensor cell 230. According to the embodiment of the device 100 of Fig. 3, the porous filter element 130 is arranged at least partially in the opening 232 in the sensor cell 230.

[0054] The sensor cell 230 forms a volume essentially separated from the interior of the battery housing 212, which is fluidly connected to the interior of the battery housing 212 via the opening 232. Alternatively, it can be located in the 202401746

[0055] 10

[0056] Sensor cell 230 is a cell extending through the wall of the battery housing 212. The gas sensor 110 can be mounted on the battery housing 212 through the wall of the battery housing 212.

[0057] In the event of thermal runaway of at least one battery cell 220, in addition to hydrogen, which the sensor element 120 of the gas sensor 110 is intended to detect, water and electrolyte in gaseous form can also form and be contained in the gas. These gas components—if they reach the sensor element 120—counteract the actual hydrogen signal of the gas sensor 110 and can therefore dampen the sensor response. By providing the porous filter element 130 made of foam, these gas components, which are detrimental to measurement accuracy, can be kept away from the sensor element 120, thereby at least partially improving the measurement accuracy and sensitivity of the sensor element 120 of the gas sensor 110.

Claims

202401746 11 Patent claims 1. Device (100) for measuring a gas mixture, wherein the device (100) comprises: a gas sensor (110) for measuring the gas mixture, wherein the gas sensor (110) has a sensor element (120) which is designed to come into contact with the gas mixture for measuring it, a gas supply path (114) configured to supply the gas to the sensor element (120) of the gas sensor (110), and a porous filter element (130) arranged in the gas supply path (114), which is designed to prevent gas components present in the gas and interfering with the measurement from reaching the sensor element (120), wherein the porous filter element (130) consists of foam.

2. Device (100) according to claim 1, wherein the porous filter element (130) consists of an open-pore foam.

3. Device (100) according to one of the preceding claims, wherein the porous filter element (130) has a thickness in the range of approximately 3 mm to approximately 5 mm.

4. Device (100) according to one of the preceding claims, wherein the porous filter element (130) has a pore number in the range of approximately 10 ppi to approximately 90 ppi.

5. Device (100) according to one of the preceding claims, wherein the porous filter element (130) is further configured to dissipate the heat of the electrolyte and / or water condensed thereon.

6. Device (100) according to one of the preceding claims, further comprising: 202401746 12 a diffusion membrane (140) arranged in the gas supply path (114), which is designed to control the gas supply of the gas mixture to be measured to the sensor element (120) at least partially in such a way that the gas mixture diffuses through the diffusion membrane (140).

7. Device (100) according to claim 6, wherein the diffusion membrane (140) is arranged downstream of the porous filter element (130).

8. Device (100) according to one of the preceding claims, wherein the gas sensor (110) has a sensor housing (112) in which the sensor element (112) is arranged, wherein the gas supply path (114) extends from the interior of the battery housing (212) into the sensor housing (112) to the sensor element (120), wherein the porous filter element (130) is at least partially arranged within the sensor housing (112).

9. Device (100) according to one of claims 1 to 7, wherein the gas sensor (110) has a sensor housing (112) in which the sensor element (120) is arranged, wherein the gas supply path (114) extends from the interior of the battery housing (212) through an opening (113) provided in the sensor housing (112) to the interior of the sensor housing (112), wherein the porous filter element (130) is at least partially arranged in the opening (113) in the sensor housing (112).

10. Device (100) according to any one of claims 1 to 7, further comprising: a sensor cell (230) arranged in the battery housing (212), in which the gas sensor (110) is arranged, wherein the gas supply path (114) extends from the interior of the battery housing (212) through an opening (232) provided in the sensor cell (230) into the interior of the sensor cell (230), wherein the porous filter element (130) is at least partially arranged in the opening (232) in the sensor cell (230).

11. Device (100) according to one of the preceding claims, wherein the porous filter element (130) is formed from a sintered metal. 202401746 13 12. Device (100) according to one of the preceding claims, wherein the porous filter element (130) is designed as a metal mesh having a mesh size in the range of approximately 5 pm to approximately 50 pm.

13. Device (100) according to one of the preceding claims, wherein the porous filter element (130) is further formed as metal spheres having a diameter in the range of approximately 5 pm to approximately 50 pm.

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