Gas sampling device

Abstract

This gas sampling device (1) comprises a sampling bottle (7) defining a sampling volume (9), is configured to be connected to a gas bag (5) and is provided with a sampling opening (11), as well as first and second liquid-impermeable and gas-permeable membranes (19; 21), the first and second membranes (19; 21) being positioned in the sampling bottle (7) and axially spaced from each other so as to divide the sampling volume (9) into a first space (23) between the sampling opening (11) and the first membrane (19), a second space (25) intended to contain an inert solvent between the first membrane (19) and the second membrane (21) and a third space (27), the sampling device (1) further comprising a system (31) for closing the sampling opening (11). Figure for abstract: Fig. 1

Description

Title of the invention: Gas sampling device Technical field

[0001] The present invention relates to gas sampling.

[0002] In particular, the present invention relates to the collection of gas emitted by an electrochemical battery cell, in particular emitted during the degradation of the electrolyte of said electrochemical cell and temporarily stored in a pocket, such cells being called "pouch cell" in English terms.

[0003] Generally speaking, the invention applies to the sampling of gas from any type of battery cell, and more generally to the sampling of gas in any type of environment and for any type of application. Previous techniques

[0004] When an electrochemical battery cell is in operation, it generally emits gases resulting from the degradation of its electrolyte.

[0005] Pouch cells are among the most widely used battery cell formats currently used, regardless of the battery technology being studied. They generally recover the gas emitted in a pouch.

[0006] From one battery cell to another, the nature and quantity of gases generated vary. In order to better understand the aging of battery cells, it is sometimes necessary to be able to analyze these gases, in research or quality control contexts.

[0007] Many gas sampling solutions exist but do not allow the sample to be transported easily and securely, or to know the volume of gas sampled, or that can be sampled.

[0008] In addition, existing solutions are generally not very solid, not very rigid, complex and bulky. In the latter case, taking samples from several battery cells in parallel is in an area with restricted space.

[0009] Solutions sometimes require placing oneself in particular and therefore restrictive pressure conditions.

[0010] In addition, certain solutions allow real-time gas analysis and therefore require positioning the gas analysis means in the immediate vicinity of the sampling location.

[0011] Other solutions are effective but require dismantling or stopping the battery cell in order to carry out the samples, which prevents other subsequent samples. Statement of the invention

[0012] The present invention therefore aims to overcome the aforementioned drawbacks and to provide a gas sampling device allowing transport of the sampled gases and making it possible to know the quantity of gas sampled.

[0013] The present invention relates to a gas sampling device comprising a sampling bottle defining a sampling volume, configured to be connected to a gas bag and provided with a sampling opening, the device comprising a first and a second liquid-impermeable and gas-permeable membrane, the first and second membranes being positioned in the sampling bottle and axially spaced from each other so as to divide the sampling volume into a first space between the sampling opening and the first membrane, a second space intended to contain an inert solvent between the first membrane and the second membrane and a third space, the sampling device further comprising a system for closing the sampling opening.

[0014] Thus, the third space is the space intended to accommodate the sampled gas, once the latter has passed through the membranes, the third space having a volume fixed and known by the user.

[0015] Advantageously, the closure system comprises a valve for closing the sampling opening, and a rigid rod secured to the valve, one end of which extends outside the sampling bottle, the rod being movable between a position for closing the sampling opening and an open position.

[0016] In one embodiment, the rod comprises a hollow internal volume, passes through the third space and comprises at least one perforation of its wall communicating the third space and the internal volume of the rod, the closure system further comprising a septum positioned in the internal volume of the rod at the end extending outside the collection bottle.

[0017] Preferably, the device comprises a flexible tube configured to connect the sampling bottle to the gas bag.

[0018] Advantageously, the sampling bottle comprises a thread and a leak-proof seal at the sampling opening, the thread being configured to accommodate a tapping of the flexible tube.

[0019] In a particular embodiment, the flexible tube comprises polyethylene and / or polypropylene and / or polytetrafluoroethylene.

[0020] Advantageously, the first and second membranes comprise polymers, preferably polytetrafluoroethylene, and / or polydimethylsiloxane, and / or silicone.

[0021] In a particular embodiment, the first and second membranes are welded and / or glued to the sampling bottle.

[0022] Advantageously, the sampling bottle comprises a transparent material.

[0023] According to one embodiment, the sampling bottle comprises glass and / or plastic chemically compatible with the sampled gases, preferably polyethylene and / or polypropylene. Brief description of the drawings

[0024] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the appended drawings in which:

[0025] [Fig.l] is a schematic view of a gas sampling device according to the invention; and

[0026] [Fig.2] is a schematic view of the device of [Fig.l] in a position for closing its sampling opening.

[0027] Detailed description of at least one embodiment

[0028] [Fig.l] schematically shows a gas sampling device 1 and a battery cell 3 of the “pouch cell” type comprising a pocket 5 intended to collect gases resulting from the deterioration of the electrolyte of said battery cell 3.

[0029] The gas sampling device 1 is configured to sample gases present in the pocket 5 of the battery cell 3.

[0030] The gas sampling device 1 comprises a sampling bottle 7 defining a sampling volume 9. The sampling bottle 7 is for example of a generally tubular shape along a longitudinal axis X-X'.

[0031] The sampling device 1 is provided with a sampling opening 11, for example located at a first longitudinal end 13 of the sampling bottle 7.

[0032] From the sampling opening 11 extends a wall 15 at a constant radial distance from the longitudinal axis X-X' to a second longitudinal end 17 of the sampling bottle 7.

[0033] In the illustrated embodiment, the sampling bottle 7 comprises a transparent material. This allows the interior of the sampling bottle 7 to be seen.

[0034] For example, the materials used to make the sampling bottle 7 comprise glass and / or plastic chemically compatible with the sampled gases, preferably polyethylene and / or polypropylene.

[0035] The device 1 further comprises first and second liquid-impermeable and gas-permeable membranes 19 and 21, the membranes 19 and 21 being positioned in the sampling bottle 7 and axially spaced apart from each other by so as to divide the sampling volume 9 into a first space 23 between the sampling opening 11 and the first membrane 19, a second space 25 between the first membrane 19 and the second membrane 21 and a third space 27 delimiting an effective sampling volume 29.

[0036] The second space 25 is intended to contain an inert solvent. An inert solvent is understood to mean a solvent compatible with the electrolytes used in the battery cells 3. For example, the inert solvent is a liquid carbonate solvent.

[0037] Any other type of liquid solvent may nevertheless be used, provided that it does not deteriorate the gas to be sampled by reacting with the latter.

[0038] The first and second membranes 19 and 21 are impermeable to liquids, in other words impermeable to the inert solvent intended to be contained between the two membranes 19 and 21. By impermeable is meant the ability of each membrane 19 and 21 not to allow the inert solvent to pass through said membranes 19 and 21. Thus, the inert solvent remains between the two membranes 19 and 21 over time.

[0039] Furthermore, the first and second membranes 19 and 21 are also permeable to gases, in particular to sampled gases. The latter can therefore, once the device 1 is connected to a gas pocket 5, migrate from the pocket 5 to the first space 23, then pass through the first membrane 19, the inert solvent, which begins to bubble, and finally the second membrane 21 in order to end up in the third space 27.

[0040] The membranes 19 and 21 are made for example from materials comprising polymers, preferably polytetrafluoroethylene, and / or polydimethylsiloxane, and / or silicone, allowing such properties of impermeability to liquids and permeability to gases.

[0041] In a particular embodiment, the membranes 19 and 21 are welded and / or glued to the sampling bottle 7, in particular to the wall of the sampling bottle 7.

[0042] The sampling device 1 further comprises a system 31 for closing the sampling opening 11.

[0043] The closure system 31 comprises a valve 33 for closing the sampling opening 11, and a rigid rod 35 secured to the valve 33, one end 37 of which extends outside the sampling bottle 7, the rod 35 being movable between a closed position PF of the sampling opening 11 illustrated in [Fig.2], and an open position PO illustrated in [Fig.1].

[0044] The rod 35 extends for example along the longitudinal axis X-X' and comprises its end 37 which emerges through the second end 17 of the sampling bottle 7.

[0045] In a particular embodiment, the sampling bottle 7 comprises a stop 38, for example extending radially towards the inside of the bottle 7 in the first space 23, making it possible to restrict the longitudinal movement of the valve 33. between the sampling opening 11 and the stop 38.

[0046] The sampling bottle 7 comprises for example a third membrane 39 impermeable to liquids and gases closing the second end 17, the third membrane 39 being crossed by the rod 35 and being flexible so as to allow the rod 35 to be positioned in its closed position PF or open position PO. The contact between the rod 35 and the third membrane 39 is maintained by the use of glue or by welding the third membrane 39 onto the rod 35.

[0047] Similarly, in the illustrated embodiment, the rod 35 passes through the first membrane 19 and the second membrane 21, for example in their center. These first and second membranes 19 and 21 are for example flexible and the contact between these membranes 19 and 21 and the rod 35 is maintained by gluing or by welding so as to allow the rod 35 to be positioned in its closed position PF or open position PO.

[0048] In the illustrated embodiment, the rod 35 comprises a hollow internal volume 41 delimited by a wall 43. The rod 35 passes through the third space 27 and comprises at least one perforation 45 of its wall 43 communicating the third space 27 and the internal volume 41 of the rod 35. The internal volume 41 of the rod 35 therefore only communicates fluidically with an external space at the level of the perforation 45.

[0049] The sealing system 31 further comprises a septum 47 positioned in the internal volume 41 of the rod 35 at the end 37 extending outside the sampling bottle 7. This septum 47 is configured to be pierced by a syringe (not shown) in order to be able to sample gas from the third space 27 via the sealing system 31 and in particular the rod 35. Once the syringe is removed, the septum 47 closes automatically and guarantees the sealing of the rod 35. The septum 47 can also be replaced.

[0050] The device 1 further comprises a flexible tube 49 configured to connect the sampling bottle 7 to the gas bag 5.

[0051] Advantageously, the sampling bottle 7 comprises a thread 51 and a leaktight seal 53 at the sampling opening 11, the thread 51 being configured to accommodate a tapping 55 fixed to a junction module 57 of the flexible tube 49.

[0052] A junction module may also be used to attach the flexible tube 49 to the battery cell 3.

[0053] The flexible tube 49 is for example made with materials comprising polyethylene and / or polypropylene and / or polytetrafluoroethylene and not reacting with the sampled gases.

[0054] When using the gas sampling device 1, the flexible tube 49 is first connected to the sampling bottle 7 by screwing the junction module 57 onto the thread 51.

[0055] Similarly, the flexible tube 49 is connected to the pocket 5 of the battery cell 3.

[0056] The user ensures that initially, the rod 35 is positioned in its opening position PO. The second space 25 must also include an inert liquid solvent.

[0057] The gas present in the pocket 5 then moves in the flexible tube 49 into the first space 23 of the sampling bottle 7.

[0058] Then, the gas passes through the first membrane 19, the solvent present in the second space 25 as well as the second membrane 21 to end up in the third space 27, in other words in the effective sampling volume 29.

[0059] By passing through the solvent, the gas forms bubbles in the solvent. The sampling bottle 7 being transparent, it is possible to see the bubbles and therefore to see that the effective sampling volume 29 is filling, even if the gas is colorless.

[0060] The effective sampling volume 29 is a known and predefined volume. Depending on the quantity of gas that the user wishes to sample, the latter uses a sampling bottle 7 of small or large capacity.

[0061] Thus, when no more bubbles are visible in the second space 25, this means that the effective sampling volume 29 is filled with gas. It is thus easy to know the quantity of gas recovered.

[0062] The user then moves the rod 35 into its closed position PF in order to close the sampling opening 11 with the closing valve 33.

[0063] The flexible tube 49 can then be separated from the sampling bottle 7 by unscrewing. A cap can be screwed onto the sampling opening 11 for greater safety during transport. Other bottles 7 can be connected to the bag 5 if further sampling is required.

[0064] The sampling bottle 7 is then an ideal container for transporting the sample to a place of analysis. Indeed, the bottle 7 is rigid and not very fragile, unlike a flexible bag or a syringe.

[0065] Then, in order to remove the gas from the effective sampling volume 29 and analyze it, the user can insert a syringe into the septum 47 and recover the gas via the internal volume 41 of the rod 35, which is fluidically in communication with the third space 27.

Claims

Claims

1. A gas sampling device (1) comprising a sampling bottle (7) defining a sampling volume (9), configured to be connected to a gas bag (5) and provided with a sampling opening (11), characterized in that it comprises first and second membranes (19; 21) impermeable to liquids and permeable to gases, the first and second membranes (19; 21) being positioned in the sampling bottle (7) and axially spaced from each other so as to divide the sampling volume (9) into a first space (23) between the sampling opening (11) and the first membrane (19), a second space (25) intended to contain an inert solvent between the first membrane (19) and the second membrane (21) and a third space (27), the sampling device (1) further comprising a system (31) for closing the sampling opening (11).

2. Device (1) according to claim 1, in which the closure system (31) comprises a valve (33) for closing the sampling opening (11), and a rigid rod (35) integral with the valve (33), one end (37) of which extends outside the sampling bottle (7), the rod (35) being movable between a closing position (PF) of the sampling opening (11) and an opening position (PO).

3. Device (1) according to claim 2, in which the rod (35) comprises a hollow internal volume (41), passes through the third space (27) and comprises at least one perforation (45) of its wall (43) communicating the third space (27) and the internal volume (41) of the rod (35), the closure system (31) further comprising a septum (47) positioned in the internal volume (41) of the rod (35) at the end (37) extending outside the sampling bottle (7).

4. Device (1) according to any one of claims 1 to 3, comprising a flexible tube (49) configured to connect the sampling bottle (7) to the gas bag (5).

5. Device (1) according to claim 4, in which the sampling bottle (7) comprises a thread (51) and a seal (53) at the sampling opening (11), the thread (51) being configured to accommodate a tapping (55) of the flexible tube (49).

6. Device (1) according to one of claims 4 and 5, in which the flexible tube (49) comprises polyethylene and / or polypropylene and / or polytetrafluoroethylene.

7. Device (1) according to one of claims 1 to 6, wherein the first and second membranes (19; 21) comprise polymers, preferably polytetrafluoroethylene, and / or polydimethylsiloxane, and / or silicone.

8. Device (1) according to any one of claims 1 to 7, in which the first and second membranes (19; 21) are welded and / or glued to the sampling bottle (7).

9. Device (1) according to any one of claims 1 to 8, wherein the sampling bottle (7) comprises a transparent material.

10. Device (1) according to any one of claims 1 to 9, wherein the sampling bottle (7) comprises glass and / or polyethylene and / or polypropylene.

Images