Breathable membrane type lithium ion battery electrolyte leakage mark

Abstract

The utility model discloses a breathable film type lithium ion battery electrolyte standard leakage device, and relates to the field of lithium ion batteries. The leakage mark comprises a leakage mark body and a breathable film, and a liquid storage cavity is formed in the leakage mark body; a vent hole is formed in the leakage mark body, and the liquid storage cavity is communicated with the outside of the leakage mark body through the vent hole; the breathable film is mounted in the breathable opening; the gas-permeable membrane is of a layered structure and comprises a high-strength supporting layer and an organic gas diffusion layer; the organic gas diffusion layer permeates into the high-strength supporting layer to form a permeation composite layer, and the thickness of the permeation composite layer accounts for 0%-100% of the thickness of the high-strength supporting layer. According to the utility model, the structure is simple and reliable, the electrolyte can be used as a calibration object, the current stabilization effect is realized through the breathable film, the electrolyte gas can overflow at a stable rate, and the accuracy and reliability of calibration, calibration and point inspection of the current leakage detection equipment are improved.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion batteries, specifically to a breathable membrane type lithium-ion battery electrolyte leveling device. Background Technology

[0002] Lithium-ion batteries possess advantages such as high energy density, high voltage, environmental friendliness, long lifespan, and fast charging capabilities, leading to their widespread application in portable devices, electric vehicles, and energy storage systems. During application, the safety of lithium-ion batteries is of paramount importance. Whether the lithium-ion electrolyte leaks is currently one of the primary safety assessment criteria for lithium-ion batteries. Currently, mass spectrometry leak detectors / equipment are commonly used for detecting lithium-ion battery electrolyte leaks; however, existing mass spectrometry leak detectors / equipment do not currently have standard leak detectors available for calibration, standardization, and spot checks.

[0003] Currently, lithium-ion battery volatile organic compound (VOC) leak detectors / equipment are calibrated, standardized, or inspected using isobutylene gas of known concentrations, rather than directly using the electrolyte of the tested material. However, due to the varying ionization efficiencies of different substances, calibration, or inspection using isobutylene gas is inaccurate. Therefore, there is a need to develop a standard leak detector that uses the electrolyte as a calibration material to improve the accuracy of VOC leak detector / equipment calibration / standardization. Utility Model Content

[0004] To address the problems existing in the prior art, a breathable membrane-type lithium-ion battery electrolyte leak indicator is provided. The electrolyte is used as the calibration material, and the breathable membrane component allows the electrolyte gas to overflow at a stable rate, thereby improving the accuracy and reliability of calibration, standardization, and inspection.

[0005] This utility model provides the following technical solution:

[0006] This utility model proposes a permeable membrane type lithium-ion battery electrolyte leveling leak, comprising a leveling leak body and a permeable membrane. The leveling leak body has a liquid storage chamber; the leveling leak body has a vent, and the liquid storage chamber is connected to the outside of the leveling leak body through the vent; the permeable membrane is installed inside the vent; the permeable membrane has a layered structure, comprising a high-strength support layer and an organic gas diffusion layer; the organic gas diffusion layer permeates into the high-strength support layer to form a permeable composite layer, and the thickness of the permeable composite layer accounts for 0%-100% of the thickness of the high-strength support layer.

[0007] Preferably, the organic gas diffusion layer has two layers, and the high-strength support layer is located between the two organic gas diffusion layers.

[0008] Preferably, the breathable membrane further includes an adhesive layer, which is connected to the high-strength support layer; the high-strength support layer is located between the adhesive layer and the organic gas diffusion layer.

[0009] Preferably, the adhesive layer has two layers, with the high-strength support layer and the organic gas diffusion layer located between the two adhesive layers.

[0010] Furthermore, the material of the organic gas diffusion layer is selected from one of perfluorosulfonic acid resin, polymethylpentene, polyimide, and graphene oxide.

[0011] Furthermore, the material of the high-strength support layer is selected from polyamide, polyolefin and polytetrafluoroethylene.

[0012] Furthermore, the adhesive layer material is selected from one of epoxy resin, silicone, fluorinated rubber, and acrylic adhesives.

[0013] Furthermore, the thickness of the organic gas diffusion layer is 0.01mm-5mm.

[0014] Furthermore, the high-strength support layer is 0.1mm-5mm thick.

[0015] Furthermore, the thickness of the adhesive layer is 0.1mm-3mm.

[0016] Furthermore, it also includes a support plate, which is disposed at the upper and lower ends of the breathable membrane, and the support plate has through holes.

[0017] Furthermore, it also includes a connecting and fixing mechanism, which is installed inside the vent; the breathable membrane and the support plate are installed on the connecting and fixing mechanism and installed inside the vent through the connecting and fixing mechanism.

[0018] Preferably, the adhesive layer can bond the breathable membrane to the support plate.

[0019] Furthermore, it also includes a top cover for the leak, which is located above the breathable membrane and is used to seal the leak.

[0020] Preferably, a sealing ring is provided between the support plate and the connecting and fixing mechanism.

[0021] This utility model has the following beneficial technical effects:

[0022] The gas-permeable membrane type lithium-ion battery electrolyte leak indicator structure of this utility model is simple and can be used to calibrate, standardize and inspect lithium-ion battery leak detection devices using electrolyte. The gas-permeable membrane structure design allows for stable evaporation of electrolyte gas, further ensuring the accuracy and reliability of the test. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic diagram of a leak and explosion of the electrolyte in a breathable membrane lithium-ion battery provided by this utility model.

[0025] Figure 2 This is a structural diagram of the breathable membrane provided in Embodiment 1 of this utility model.

[0026] Figure 3 This is a structural diagram of the breathable membrane provided in Embodiment 2 of this utility model.

[0027] Figure 4 This is a structural diagram of the breathable membrane provided in Embodiment 3 of this utility model.

[0028] Figure 5 This is a structural diagram of the breathable membrane provided in Embodiment 4 of this utility model.

[0029] Figure 6 This is a structural diagram of the breathable membrane provided in Embodiment 6 of this utility model.

[0030] Figure 7 The stability test results of Embodiment 1 and Comparative Examples 1-4 provided for this utility model are shown in the figure.

[0031] Figure 8 The stability test results of Embodiment 1, Comparative Example 5 and Comparative Example 6 provided for this utility model are shown in the figure.

[0032] Figure 9 The diagram shows the long-term stability test results of Embodiment 1 provided by this utility model.

[0033] Explanation of the markings in the image:

[0034] 1-Leakage indicator body; 2-Liquid storage chamber; 3-Ventilation port; 4-Connecting and fixing mechanism; 5-Support plate; 6-Ventilating membrane; 601-Organic gas diffusion layer; 602-High-strength support layer; 603-Permeable composite layer; 604-Adhesive layer; 604A-First adhesive layer; 604B-Second adhesive layer; 7-Leakage indicator cover; 8-Sealing ring. Detailed Implementation

[0035] The technical solution of this utility model will be clearly and completely described below with reference to its embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0036] It should be understood that, when used in this specification and the appended claims, the terms “comprising” and “including” indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0037] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0038] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0039] It should be noted that when testing samples prepared using the same method, the results may fluctuate to some extent, which does not indicate that the data is incorrect.

[0040] Example 1

[0041] Please see Figure 1The illustrated permeable membrane type lithium-ion battery electrolyte leveling leak includes a leveling leak body 1, a permeable membrane 6, a support plate 5, a connecting and fixing mechanism 4, and a leveling leak cover 7. The leveling leak body 1 has a liquid storage chamber 2; a vent 3 is provided on the leveling leak body 1, and the liquid storage chamber 2 communicates with the outside of the leveling leak body 1 through the vent 3; the permeable membrane 6 is installed inside the vent 3. Two support plates 5 are provided, respectively located at the upper and lower ends of the permeable membrane 6, and through holes are provided on the support plates 5 for gas flow. The connecting and fixing mechanism 4 is installed in the vent 3; the permeable membrane 6 and the support plate 5 are installed within the connecting and fixing mechanism 4, and a sealing ring 8 is provided between the support plate 5 and the connecting and fixing mechanism 4. The sealing ring 8 is tightened to achieve fixation and ensure the sealing performance of the connection. The leveling leak cover 7 is placed on top of the permeable membrane 6 to seal the leveling leak.

[0042] For details, please refer to further information. Figure 2 The breathable membrane 6 has a three-layer structure, including a high-strength support layer 602, an organic gas diffusion layer 601, and an adhesive layer 604. The adhesive layer 604 is connected to the high-strength support layer 602. The high-strength support layer 602 is located between the adhesive layer 604 and the organic gas diffusion layer 601. The organic gas diffusion layer 601 permeates into the high-strength support layer 602 to form a permeable composite layer 603.

[0043] Specifically, the organic gas diffusion layer 601 is made of graphene oxide; the high-strength support layer 602 is made of polyamide; and the adhesive layer 604 is made of silicone.

[0044] Specifically, the organic gas diffusion layer 601 has a thickness of 0.57 mm; the high-strength support layer 602 has a thickness of 2.33 mm; and the adhesive layer 604 has a thickness of 0.86 mm. The thickness of the permeation composite layer 603 is 50% of the thickness of the high-strength support layer 602.

[0045] Example 2

[0046] The difference between this embodiment and Embodiment 1 lies in the breathable membrane 6.

[0047] Please refer to the details. Figure 3 In this embodiment, the breathable membrane 6 has a double-layer structure, including a high-strength support layer 602 and an organic gas diffusion layer 601, and the organic gas diffusion layer 601 permeates into the high-strength support layer 602 to form a permeable composite layer 603.

[0048] Specifically, the organic gas diffusion layer 601 is made of perfluorosulfonic acid resin; the high-strength support layer 602 is made of polyolefin.

[0049] Specifically, the organic gas diffusion layer 601 has a thickness of 5 mm; the high-strength support layer 602 has a thickness of 5 mm; and the thickness of the permeation composite layer 603 is 0% of the thickness of the high-strength support layer 602, meaning that in this embodiment, the organic gas diffusion layer 601 does not permeate into the high-strength support layer 602.

[0050] Example 3

[0051] The difference between this embodiment and Embodiment 1 lies in the breathable membrane 6.

[0052] Please refer to the details. Figure 4 In this embodiment, the breathable membrane 6 has a three-layer structure, including a high-strength support layer 602 and two organic gas diffusion layers 601. The high-strength support layer 602 is disposed between the two organic gas diffusion layers 601, and both organic gas diffusion layers 601 permeate into the high-strength support layer 602 to form a permeable composite layer 603.

[0053] Specifically, both organic gas diffusion layers 601 are made of polyimide; the high-strength support layer 602 is made of polytetrafluoroethylene.

[0054] Specifically, the thicknesses of the two organic gas diffusion layers 601 are 0.01 mm and 0.05 mm, respectively, and the thickness of the high-strength support layer 602 is 0.1 mm. The thickness of the permeation composite layer 603 accounts for 33% of the thickness of the high-strength support layer 602. Among them, the 0.01 mm thick organic gas diffusion layer 601 penetrates into the high-strength support layer 602 to a depth of 8% of the high-strength support layer 602, and the 0.05 mm thick organic gas diffusion layer 601 penetrates into the high-strength support layer 602 to a depth of 25% of the high-strength support layer 602.

[0055] Example 4

[0056] The difference between this embodiment and Embodiment 1 lies in the breathable membrane 6.

[0057] Please refer to the details. Figure 5 In this embodiment, the breathable membrane 6 has a four-layer structure, including a high-strength support layer 602, an organic gas diffusion layer 601, and two adhesive layers 604. The adhesive layers 604 include a first adhesive layer 604A and a second adhesive layer 604B. The first adhesive layer 604A is connected to the organic gas diffusion layer 601, and the second adhesive layer 604B is connected to the high-strength support layer 602. The high-strength support layer 602 and the organic gas diffusion layer 601 are disposed between the two adhesive layers 604. The high-strength support layer 602 and the organic gas diffusion layer 601 are connected, and the organic gas diffusion layer 601 permeates into the high-strength support layer 602 to form a permeable composite layer 603. Specifically, the organic gas diffusion layer 601 is made of polyimide; the high-strength support layer 602 is made of polyamide.

[0058] Specifically, the organic gas diffusion layer 601 has a thickness of 5 mm; the high-strength support layer 602 has a thickness of 5 mm; the first adhesive layer 604A has a thickness of 1 mm; the second adhesive layer 604B has a thickness of 3 mm; and the thickness of the permeation composite layer 603 accounts for 45% of the thickness of the high-strength support layer 602.

[0059] Specifically, the adhesive layer 604 is used to bond the breathable membrane 6 to the support plate 5.

[0060] Example 5

[0061] The difference between this embodiment and Embodiment 1 is that, specifically, the thickness of the organic gas diffusion layer 601 is 0.1 mm; the thickness of the high-strength support layer 602 is 0.1 mm; and the thickness of the adhesive layer 604 is 0.1 mm. The thickness of the permeation composite layer 603 accounts for 20% of the thickness of the high-strength support layer 602.

[0062] Example 6

[0063] The difference between this embodiment and Embodiment 1 lies in the breathable membrane 6.

[0064] Please refer to further information. Figure 6 In this embodiment, the breathable membrane 6 has a five-layer structure, including a high-strength support layer 602, two organic gas diffusion layers 601, and two adhesive layers 604. The high-strength support layer 602 is disposed between the two organic gas diffusion layers 601, and the high-strength support layer 602 and the organic gas diffusion layer 601 are disposed between the two adhesive layers 604. The organic gas diffusion layer 601 permeates into the high-strength support layer 602 to form a permeable composite layer 603. Specifically, both organic gas diffusion layers 601 are made of polyimide; the high-strength support layer 602 is made of polyamide; and both adhesive layers 604 are made of silicone.

[0065] Specifically, the thickness of both organic gas diffusion layers 601 is 0.1 mm; the thickness of the high-strength support layer 602 is 0.1 mm; the thickness of both adhesive layers 604 is 0.1 mm; and the thickness of the permeation composite layer 603 is 100% of the thickness of the high-strength support layer 602.

[0066] Example 7

[0067] The difference between this embodiment and Embodiment 1 is that the thickness of the organic gas diffusion layer is 0.83 mm.

[0068] The working principle of the breathable membrane type lithium-ion battery electrolyte leakage indicator of this utility model is as follows:

[0069] The electrolyte in the storage chamber evaporates into gas, existing in a gas-liquid coexistence state within the chamber. A permeable membrane lithium-ion battery electrolyte standard leak is placed inside the mass spectrometer chamber. The chamber is evacuated, and under the pressure difference and the flow stabilization effect of the permeable membrane component, the electrolyte gas in the storage chamber evaporates at a stable rate into the mass spectrometer chamber and is detected. The mass spectrometer performs calibration, adjustment, or inspection based on the detected electrical signal intensity and the leakage rate of the permeable membrane lithium-ion battery electrolyte standard leak. When the standard leak exceeds its service life and the electrolyte or other liquid inside the storage chamber has evaporated completely, the sealing component of the injection port is opened, and new electrolyte or other liquid is added to the storage chamber using a syringe or other means. The injection port sealing component is then reinstalled, and the standard leak can be reused.

[0070] To illustrate the technical effects of this utility model, stability tests were conducted on the leakage of the samples in Examples 1-6.

[0071] Test Method: The standard leaks of the permeable membrane lithium-ion battery electrolytes from Examples 1-6 were placed inside the mass spectrometer chamber. The chamber was evacuated to allow the electrolyte gas in the storage chamber to evaporate into the mass spectrometer chamber and be detected. The leak rate was measured every ten minutes, with 10 measurements per group. The average value and the coefficient of variation for each group were then calculated. The specific results are shown in Table 1 below.

[0072] Table 1. Stability test results of Examples 1-6

[0073]

[0074]

[0075] As shown in Table 1, the average leakage rate of the permeable membrane-type lithium-ion battery electrolyte of this invention can be maintained at 3×10⁻⁶. -7 -7×10 -4 The measured value of mbar*L / s and the variation index being maintained within 15% indicate that the permeable membrane-type lithium-ion battery electrolyte of this invention has good leakage stability.

[0076] To investigate the influence of the structure and material of the breathable membrane on the stability of the leak, comparative examples 1-4 were set up based on Example 1 as follows.

[0077] Comparative Example 1

[0078] The difference from Example 1 is that the breathable membrane has a single-layer structure, is made of polypropylene (PP), and has a thickness of 3.76 mm.

[0079] Comparative Example 2

[0080] The difference from Example 1 is that the breathable membrane is a single-layer structure, made of polyethylene film (PE film), and the thickness of the breathable membrane is 3.76 mm.

[0081] Comparative Example 3

[0082] The difference from Example 1 is that the breathable membrane is a single-layer structure, made of polyurethane (TPU), and the thickness of the breathable membrane is 3.76 mm.

[0083] Comparative Example 4

[0084] The difference from Example 1 is that the breathable membrane is a single-layer structure, made of polytetrafluoroethylene (PTEE), and the thickness of the breathable membrane is 3.76 mm.

[0085] Stability tests were conducted on the standard leakage of Comparative Examples 1-4 and Example 1, using the same testing methods as in Examples 1-6. The test results are shown in Table 2 below. A comparison of the stability test results of Example 1 and Comparative Examples 1-4 is plotted based on the data in Table 2. Figure 7 As shown.

[0086] Table 2 shows the stability test results of Example 1 and Comparative Examples 1-4.

[0087]

[0088]

[0089] As shown in Table 2 and Figure 7 As shown, when using breathable membranes with other structures or materials in the test leak, the coefficient of variation is much higher than that of the breathable membrane in this application. That is, changing the structure and material of the breathable membrane in this application will lead to a significant reduction in the stability of the test leak. The data in Example 1 in Table 2 deviate from those in Table 1. This is because the same scheme will fluctuate in two tests, which is a normal phenomenon.

[0090] To further verify the effect of the thickness of the breathable membrane on the stability of the standard leak in this invention, comparative examples 5 and 6 were set up based on Example 1 as follows.

[0091] Comparative Example 5

[0092] The difference from Example 1 is that the thickness of the organic diffusion layer is 0.006 mm.

[0093] Comparative Example 6

[0094] The difference from Example 1 is that the thickness of the organic diffusion layer is 5.5 mm.

[0095] The stability tests of Comparative Examples 5, 6, and Example 1 were compared using the same methods as those used in Examples 1-6. The test results are shown in Table 3 below. Based on the data in Table 2, a comparison graph of the stability test results of Example 1 and Comparative Examples 5 and 6 is plotted as follows. Figure 8 As shown.

[0096] Table 3. Stability test results of Example 1 and Comparative Examples 5 and 6

[0097]

[0098] As shown in Table 3 and Figure 8 As shown, when the thickness of the breathable membrane in this application is changed, the coefficient of variation is greater than 10%, and the stability of the calibration leak deteriorates. In addition, when the thickness of the organic diffusion layer is lower than the range of this application (Comparative Example 5), the average leak rate is too high; when the thickness of the organic diffusion layer is higher than the range of this application (Comparative Example 6), the average leak rate is too low. Excessively high or low leak rates affect the breathability of the breathable membrane, resulting in insufficient calibration accuracy. Furthermore, excessively high leak rates can easily lead to instrument contamination.

[0099] Furthermore, to further illustrate the long-term stability of the permeable membrane type lithium-ion battery electrolyte standard leak of this utility model, a long-term stability test was conducted on the standard leak of Example 7. The test method was the same as that of Examples 1-6 above, and the test was conducted continuously for 39 days (November 21, 2023 - January 5, 2024). The test results are shown in Table 3 below. Based on the data in Table 3, a graph of the long-term stability test results is plotted as follows. Figure 9 As shown.

[0100] Table 3. Long-term stability test results of Example 7

[0101]

[0102]

[0103]

[0104]

[0105] As shown in Table 3 and Figure 9 As shown, during the first four days of use, the leak indicator is in its aging period, during which the leak rate is steadily increasing. After four days, the leak indicator values ​​are very stable, and the daily coefficient of variation remains below 5%. This demonstrates that the leak indicator of this application has long-term stability, and its use in the calibration, standardization, and inspection of leak detection equipment can improve the accuracy of the detection results.

[0106] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A breathable membrane type lithium-ion battery electrolyte leak indicator, characterized in that, The device includes a leak gauge body and a breathable membrane. The leak gauge body has a liquid storage chamber. The leak gauge body has a vent, and the liquid storage chamber is connected to the outside of the leak gauge body through the vent. The breathable membrane is installed inside the vent. The breathable membrane has a layered structure, including a high-strength support layer and an organic gas diffusion layer. The organic gas diffusion layer permeates into the high-strength support layer to form a permeable composite layer, and the thickness of the permeable composite layer is 0%-100% of the thickness of the high-strength support layer.

2. The permeable membrane type lithium-ion battery electrolyte leak indicator as described in claim 1, characterized in that, The organic gas diffusion layer has two layers, and the high-strength support layer is located between the two organic gas diffusion layers.

3. The permeable membrane type lithium-ion battery electrolyte leak indicator as described in claim 1, characterized in that, The breathable membrane further includes an adhesive layer, which is connected to a high-strength support layer; the high-strength support layer is located between the adhesive layer and the organic gas diffusion layer.

4. The permeable membrane type lithium-ion battery electrolyte leak indicator as described in claim 3, characterized in that, The adhesive layer has two layers, with the high-strength support layer and the organic gas diffusion layer located between the two adhesive layers.

5. The permeable membrane type lithium-ion battery electrolyte leak indicator as described in claim 4, characterized in that, The thickness of the organic gas diffusion layer is 0.01mm-5mm.

6. The permeable membrane type lithium-ion battery electrolyte leak indicator as described in claim 5, characterized in that, The high-strength support layer is 0.1mm-5mm thick.

7. The permeable membrane type lithium-ion battery electrolyte leak indicator as described in claim 6, characterized in that, The thickness of the adhesive layer is 0.1mm-3mm.

8. The permeable membrane type lithium-ion battery electrolyte leak indicator as described in any one of claims 1-7, characterized in that, It also includes a support plate, which is disposed at the upper and lower ends of the breathable membrane, and the support plate has through holes.

9. The permeable membrane type lithium-ion battery electrolyte leak indicator as described in any one of claims 1-7, characterized in that, It also includes a connecting and fixing mechanism, which is set on the leak mark body; the breathable membrane and the support plate are installed in the connecting and fixing mechanism and connected to the leak mark body through the connecting and fixing mechanism.

10. The permeable membrane type lithium-ion battery electrolyte leak indicator as described in any one of claims 1-7, characterized in that, It also includes a leak gauge cover, which is positioned above the breathable membrane.

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