Method for measuring thickness of each layer of al-plastic film

Abstract

The application provides a kind of aluminium plastic film each layer thickness determination method.The aluminium plastic film provided by the application includes sequentially laminated composite nylon layer, aluminium foil layer and polypropylene layer, and the determination method of each layer thickness includes: S1, the thickness of aluminium plastic film is measured, and is recorded as H1;S2, the aluminium plastic film is immersed in the first acidic solution for soaking treatment, the aluminium foil layer is dissolved, and the nylon layer and the polypropylene layer are obtained;S3, the thickness of the nylon layer is measured and recorded as H2, the thickness of the polypropylene layer is measured and recorded as H3, and the thickness of the aluminium foil layer is recorded as H4, H4=H1-H2-H3.The application is immersed in the first acidic solution for soaking treatment, the aluminium foil layer is dissolved, so that the nylon layer and the polypropylene layer are separated, the thickness of the nylon layer and the polypropylene layer is measured respectively, and the thickness of the aluminium foil layer is calculated, which is not only simple in operation, low in raw material cost and easy to obtain, but also can determine the thickness of each layer simultaneously, and the determination result is accurate, which can effectively meet the determination requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery, in particular to a method for measuring thickness of each layer of aluminum-plastic film. BACKGROUND

[0002] Aluminum-plastic film is one of the important materials of soft package lithium battery, which can provide a sealed environment for the battery and prevent moisture and air from entering the battery. The aluminum-plastic film is composed of an outer nylon layer, an intermediate aluminum foil layer, and an inner polypropylene layer (also known as PP layer).

[0003] During the forming process of the aluminum-plastic film, the aluminum-plastic film will be stretched and deformed, and the thickness of each layer will be thinned, among which the aluminum foil layer is most prone to breakage. Taking a power battery as an example, the commonly used aluminum-plastic film has a thickness of 150-153 μm, including a nylon layer of 30 μm, an aluminum layer of 40 μm, and a polypropylene layer of 80 μm. The aluminum foil layer of the aluminum-plastic film after forming is required to have a thickness of ≥20 μm, otherwise the water and air resistance of the aluminum-plastic film will be reduced.

[0004] In the industry, the thickness of each layer is generally measured by cutting. A slicing machine is used to cut the aluminum-plastic film, and the thickness of each material on the cross section is measured. This method has the problems of high cost, poor accuracy, and slow efficiency. In the prior art, there is also a method of using water crystal glue forming to measure the thickness of the aluminum foil layer. However, in the actual operation process, it is not easy to place and control the measurement position, and the overall morphology of the aluminum foil layer cannot be directly observed. In addition, due to the stress deformation of the aluminum foil layer at the edge, the measurement is not accurate. SUMMARY

[0005] The main purpose of the present application is to provide a method for measuring the thickness of each layer of aluminum-plastic film, so as to solve the problems of high cost, poor accuracy, and slow efficiency of the cutting method in the prior art, and the problems of not easy to control the measurement position and not easy to directly observe the overall morphology of the aluminum foil layer in the water crystal glue forming method, which can cause inaccurate measurement.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a method for measuring the thickness of each layer of aluminum-plastic film is provided, the aluminum-plastic film includes a nylon layer, an aluminum foil layer and a polypropylene layer which are sequentially laminated and compounded, the method includes: step S1, measuring the thickness of the aluminum-plastic film, denoted as H1; step S2, immersing the aluminum-plastic film in a first acidic solution for soaking treatment, the aluminum foil layer is dissolved, and the nylon layer and the polypropylene layer are obtained; step S3, measuring the thickness of the nylon layer, denoted as H2, measuring the thickness of the polypropylene layer, denoted as H3, and measuring the thickness of the aluminum foil layer, denoted as H4, H4=H1-H2-H3.

[0007] As an implementation manner, the first acidic solution includes at least one of a hydrochloric acid solution or a sulfuric acid solution, the mass concentration of the hydrochloric acid solution is 5% to 20%, and the mass concentration of the sulfuric acid solution is 2% to 35%.

[0008] As an implementation, the temperature of the first acidic solution is 0-10℃. The reaction between the acid and the metal releases a large amount of heat in a short time. If the heat cannot be removed in time, the nylon layer and the polypropylene layer will shrink due to heat, and the thickness will change. Therefore, the acid solution in the present application is subjected to cold storage treatment.

[0009] As an implementation, the temperature of the soaking treatment is 0-40℃, or 10-20℃, and the soaking treatment time is 20-80s, or 50-70s.

[0010] As an implementation, step S2 includes: first rinsing the aluminum plastic film with a second acidic solution, and then soaking treatment. The temperature of the second acidic solution is 0-10℃, which prevents the nylon layer and the polypropylene layer from shrinking due to heat release during the rinsing process, and the thickness changes.

[0011] As an implementation, the second acidic solution includes at least one of a hydrochloric acid solution or a sulfuric acid solution. The mass concentration of the hydrochloric acid solution is 10%-20%, and the mass concentration of the sulfuric acid solution is 15%-35%.

[0012] As an implementation, step S2 further includes: step S21, after soaking treatment by immersing the aluminum plastic film in the first acidic solution, the undissolved nylon layer and the undissolved polypropylene layer are taken out of the first acidic solution to obtain a nylon layer to be cleaned and a polypropylene layer to be cleaned; step S22, the nylon layer to be cleaned and the polypropylene layer to be cleaned are subjected to water washing and air drying respectively in sequence to obtain the nylon layer and the polypropylene layer.

[0013] As an implementation, step S2 further includes step S20, which soaks the aluminum plastic film in water and air dries before step S21.

[0014] As an implementation, the temperature of soaking in water is 40-50℃, and the time is 6-9h.

[0015] As an implementation, the distance between any two non-adjacent points on the surface of the aluminum plastic film is 0.3-6.0cm, or 2.0-5.0cm.

[0016] As an implementation, the area of the aluminum plastic film is 1-33cm 2 , or 4-30cm 2 .

[0017] As an implementation, the tool for measuring steps S1 and S3 includes a micrometer or a vernier caliper.

[0018] According to the technical scheme of the present application, the aluminum plastic film is immersed in the first acidic solution for soaking treatment, the aluminum foil layer is dissolved, the nylon layer and the polypropylene layer are separated, the thicknesses of the nylon layer and the polypropylene layer are respectively measured, and the thickness of the aluminum foil layer is calculated according to the thickness of the aluminum plastic film, the thickness of the nylon layer and the thickness of the polypropylene layer. The operation is simple, the raw materials are cheap and easy to obtain, the thicknesses of the nylon layer, the aluminum foil layer and the polypropylene layer can be simultaneously measured, the simultaneous measurement result is accurate, and the measurement requirements can be effectively met. DETAILED DESCRIPTION

[0019] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0020] As analyzed in the background art of the present application, the existing technology has high cost, poor accuracy and slow efficiency in measuring the thickness of each layer by the sectioning method, and the measurement position is not easy to control and the overall morphology of the aluminum foil layer cannot be directly observed by the crystal glue forming method, which may cause inaccurate measurement.

[0021] In order to solve the problem, the present application provides a method for measuring the thickness of each layer of an aluminum plastic film, the aluminum plastic film comprising a nylon layer, an aluminum foil layer and a polypropylene layer which are sequentially stacked and combined, the method comprising: step S1, measuring the thickness of the aluminum plastic film, denoted as H1; step S2, immersing the aluminum plastic film in a first acidic solution for soaking treatment, the aluminum foil layer is dissolved, and the nylon layer and the polypropylene layer are obtained; step S3, measuring the thickness of the nylon layer denoted as H2, measuring the thickness of the polypropylene layer denoted as H3, and measuring the thickness of the aluminum foil layer denoted as H4, H4=H1-H2-H3.

[0022] According to the technical scheme of the present application, the aluminum plastic film is immersed in the first acidic solution for soaking treatment, the aluminum foil layer is dissolved, the nylon layer and the polypropylene layer are separated, the thicknesses of the nylon layer and the polypropylene layer are respectively measured, and the thickness of the aluminum foil layer is calculated according to the thickness of the aluminum plastic film, the thickness of the nylon layer and the thickness of the polypropylene layer. The operation is simple, the raw materials are cheap and easy to obtain, the thicknesses of the nylon layer, the aluminum foil layer and the polypropylene layer can be simultaneously measured, the simultaneous measurement result is accurate, and the measurement requirements can be effectively met.

[0023] The type of the tool used for measurement in the above-mentioned steps S1 and S3 is not limited, and any measuring instrument capable of measuring micrometer-level length can be used. From the perspective of cost reduction, a micrometer or a millimeter can be used.

[0024] In the step S1, the type of the aluminum-plastic film is not limited, and can be a raw aluminum-plastic film before punching or an aluminum-plastic film after punching. When the aluminum-plastic film is the aluminum-plastic film after punching, the position for measuring the thickness is not limited, and can be any position of the aluminum-plastic film after punching, including the ball corner position and the top sealing edge position.

[0025] In order to facilitate the measurement of the thickness of each layer at a specific position of the aluminum-plastic film, the aluminum-plastic film at the specific position is cut from the large aluminum-plastic film after marking and cutting, and then the thickness of each layer is measured according to the above method.

[0026] In order to further reduce the measurement error of the thickness of each layer, the distance between any two non-adjacent points on the surface of the aluminum-plastic film is 0.3-6.0 cm, and especially when the distance between any two non-adjacent points is 2.0-5.0 cm, the accuracy of the measurement of the thickness of each layer is higher.

[0027] In order to further reduce the measurement error of the thickness of each layer, the area of the surface of the aluminum-plastic film is 1-33 cm 2 , and especially when the area of the surface of the aluminum-plastic film is 4-30 cm 2 , the accuracy of the measurement of the thickness of each layer is higher.

[0028] The first acidic solution can dissolve the aluminum foil layer, but cannot dissolve the nylon layer and the polypropylene layer. In order to reduce the cost, the first acidic solution is any one of a hydrochloric acid solution or a sulfuric acid solution. In order to reduce the operation risk and improve the dissolution efficiency, the mass concentration of the hydrochloric acid solution is 5%-20%, and the mass concentration of the sulfuric acid solution is 2%-35%.

[0029] Typically but not limitedly, the mass concentration of the hydrochloric acid solution as the first acidic solution is, for example, 5%, 8%, 10%, 12%, 15%, 18%, 20%, or a range value formed by any two of the above values; and the mass concentration of the sulfuric acid solution as the first acidic solution is, for example, 2%, 3%, 5%, 10%, 15%, 20%, 25%, 30%, or a range value formed by any two of the above values.

[0030] In order to avoid that the temperature of the acidic solution is too high and the heat release during the dissolution of the aluminum foil layer causes the soaking temperature to be too high, which affects the morphology of the nylon layer and the polypropylene layer, and further affects the thickness accuracy of the nylon layer and the polypropylene layer, the temperature of the first acidic solution is 0-10℃.

[0031] In order to avoid the influence of too high soaking temperature or too long soaking time on the morphology of the nylon layer and the polypropylene layer, and thus on the thickness accuracy of the nylon layer and the polypropylene layer, too low soaking temperature will reduce the reaction rate, and too short soaking time will not completely dissolve the aluminum foil layer, thus affecting the thickness accuracy of the nylon layer and the polypropylene layer. The soaking treatment temperature is 0-40℃, and the soaking treatment time is 20-80s. Especially when the soaking treatment temperature is 10-20℃ and the soaking treatment time is 50-70s, the soaking treatment efficiency is higher.

[0032] Typically but not limitedly, the temperature of the first acidic solution is, for example, 0℃, 2℃, 5℃, 8℃, 10℃, or a range value composed of any two of the above values; the soaking treatment temperature in the first acidic solution is, for example, 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 40℃, or a range value composed of any two of the above values; and the time is, for example, 20s, 25s, 30s, 40s, 50s, 60s, 70s, 80s, or a range value composed of any two of the above values.

[0033] In order to avoid the influence of the passivation layer on the soaking treatment efficiency, step S2 includes: first flushing the aluminum plastic film with a second acidic solution, and then soaking treatment.

[0034] In order to avoid the deformation of each layer caused by too high temperature of the second acidic solution, the temperature of the second acidic solution is 0-10℃.

[0035] In order to improve the flushing efficiency and reduce the cost, the second acidic solution is any one or a mixture of the two of hydrochloric acid solution or sulfuric acid solution. In order to eliminate the possible passivation layer on the surface of the aluminum plastic film, the mass concentration of the hydrochloric acid solution is 10%-20%, and the mass concentration of the sulfuric acid solution is 15%-35%.

[0036] Typically but not limitedly, the mass concentration of the hydrochloric acid solution as the second acidic solution is, for example, 10%, 12%, 15%, 18%, 20%, or a range value composed of any two of the above values; and the mass concentration of the sulfuric acid solution is, for example, 15%, 18%, 20%, 22%, 25%, 30%, 35%, or a range value composed of any two of the above values.

[0037] In order to reduce the influence of impurities attached to the surface of the nylon layer and the polypropylene layer after the soaking treatment on the accuracy of the thickness determination, and to reduce the pollution and corrosion of the acid solution to the instruments in the subsequent operation process, step S2 comprises: step S21, after the aluminum plastic film is soaked in the first acid solution for the soaking treatment, the undissolved nylon layer and the undissolved polypropylene layer are taken out from the first acid solution, and the nylon layer to be cleaned and the polypropylene layer to be cleaned are obtained; step S22, the nylon layer to be cleaned and the polypropylene layer to be cleaned are sequentially subjected to water washing and air drying respectively, and the nylon layer and the polypropylene layer are obtained.

[0038] In order to further weaken the bonding force between the layers and promote the better separation of the aluminum foil layer from the nylon layer and the polypropylene layer during the soaking process, step S2 further comprises step S20, which is performed after the aluminum plastic film is soaked in water and dried.

[0039] In order to further weaken the bonding force between the layers and promote the better separation of the aluminum foil layer from the nylon layer and the polypropylene layer during the soaking process, step S2 further comprises step S20, which is performed after the aluminum plastic film is soaked in water and dried.

[0040] Typically but not limitedly, in step S20, the temperature of soaking in water is 40-50℃, and the time is 6-9h.

[0041] The beneficial effects of the present application will be described below in conjunction with examples.

[0042] Example 1

[0043] The present embodiment provides a method for measuring the thickness of each layer of an un-punched aluminum plastic film, which comprises a nylon layer, an aluminum foil layer and a polypropylene layer stacked and compounded in sequence, and the method comprises:

[0044] (1) marking the position to be determined on the surface of the nylon layer and the surface of the polypropylene layer of the aluminum plastic film with a marker pen, and cutting the region containing the position to be determined along the mark of the position to be determined with scissors to obtain a test aluminum plastic film, and the surface area of the test aluminum plastic film is 5cm x 5cm;

[0045] (2) measuring the thickness of the position to be determined marked on the test aluminum plastic film with a micrometer, and the thickness is denoted as H1;

[0046] (3) placing the test aluminum plastic film into a constant-temperature water bath, soaking it at 45℃ for 8h, and then taking it out and drying it to obtain a cleaned test aluminum plastic film;

[0047] (4) washing the cleaned test aluminum plastic film with a 30mL volume of 8℃ temperature and 15% mass concentration hydrochloric acid solution to obtain a washed test aluminum plastic film;

[0048] (5) The rinsed aluminum-plastic film to be detected is immersed in a 5% hydrochloric acid solution with a volume of 100 mL and a temperature of 8°C for soaking treatment. After 60 seconds of soaking treatment, the aluminum foil layer in the aluminum-plastic film to be detected is dissolved, and the nylon layer to be cleaned and the polypropylene layer to be cleaned are obtained.

[0049] (6) The nylon layer to be cleaned and the polypropylene layer to be cleaned are taken out from the hydrochloric acid solution with tweezers, washed with clean water, and dried to obtain the nylon layer and the polypropylene layer.

[0050] (7) The thickness of the position mark to be measured on the nylon layer is measured with a micrometer and recorded as thickness H2. The thickness of the position mark to be measured on the polypropylene layer is measured with a micrometer and recorded as thickness H3. The thickness H4 of the aluminum foil layer is calculated according to H4 = H1-H2-H3.

[0051] Example 2

[0052] The difference between this example and Example 1 is that in step (5), a 5% hydrochloric acid solution is used, the soaking treatment time is 80 seconds, and the soaking treatment temperature is 40°C.

[0053] Example 3

[0054] The difference between this example and Example 1 is that in step (5), a 20% hydrochloric acid solution is used, the soaking treatment time is 20 seconds, and the soaking treatment temperature is 0°C.

[0055] Example 4

[0056] The difference between this example and Example 1 is that in step (5), a 2% sulfuric acid solution is used instead of a hydrochloric acid solution.

[0057] Example 5

[0058] The difference between this example and Example 1 is that in step (5), a 35% sulfuric acid solution is used instead of a hydrochloric acid solution.

[0059] Example 6

[0060] The difference between this example and Example 1 is that in step (5), the temperature of the hydrochloric acid solution is 20°C, and the soaking treatment temperature is 40°C.

[0061] Example 7

[0062] The difference between this example and Example 1 is that in step (1), the surface area of the aluminum-plastic film to be detected obtained by cutting is 1 cm x 1 cm.

[0063] Example 8

[0064] The difference between the present embodiment and Example 1 is that in step (1), the area of the surface of the aluminum-plastic film to be detected obtained by shearing is 0.5 cm x 0.5 cm.

[0065] Example 9

[0066] The difference between the present embodiment and Example 1 is that the present embodiment measures the thickness of the top seal edge position of the aluminum-plastic film after the pit forming.

[0067] Example 10

[0068] The difference between the present embodiment and Example 1 is that the present embodiment measures the thickness of the ball corner position of the aluminum-plastic film with a pit depth of 6.5 mm.

[0069] The accuracy of the thickness of each layer in Examples 1 to 8 was calculated based on the thickness of each layer of the aluminum-plastic film measured in each of the above embodiments and comparative examples, and the theoretical thickness of each layer in the aluminum-plastic film without pit forming in Examples 1 to 8, and the results are shown in Table 1 below.

[0070] Table 1

[0071]

[0072] Note: Since Examples 9 to 10 do not have the theoretical thickness of each layer, the theoretical thickness of each layer and the measurement accuracy are not shown in Examples 9 to 10.

[0073] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects: by applying the technical solution of the present application, the present application measures the thickness of the nylon layer and the polypropylene layer separately by immersing the aluminum-plastic film in a first acidic solution for soaking treatment, dissolving the aluminum foil layer to separate the nylon layer and the polypropylene layer, and calculating the thickness of the aluminum foil layer based on the thickness of the aluminum-plastic film, the thickness of the nylon layer, and the thickness of the polypropylene layer. This not only has simple operation and low-cost raw materials, but also can simultaneously measure the thickness of the nylon layer, the aluminum foil layer, and the polypropylene layer, and the measurement results are accurate, which can effectively meet the measurement requirements.

[0074] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for measuring the thickness of each layer of an aluminum laminate film, characterized by, The aluminum plastic film comprises a nylon layer, an aluminum foil layer and a polypropylene layer which are stacked in sequence, and the determination method comprises: Step S1, measuring the thickness of the aluminum plastic film, denoted as H1; Step S2, immersing the aluminum plastic film in a first acidic solution for soaking treatment, the aluminum foil layer is dissolved to obtain the nylon layer and the polypropylene layer; the step S2 further comprises: first rinsing the aluminum plastic film with a second acidic solution, and then performing the soaking treatment; Step S3, measuring the thickness of the nylon layer denoted as H2, measuring the thickness of the polypropylene layer denoted as H3, and measuring the thickness of the aluminum foil layer denoted as H4, H4=H1-H2-H3.

2. The assay method according to claim 1, characterized by The first acidic solution comprises at least one of a hydrochloric acid solution or a sulfuric acid solution, the mass concentration of the hydrochloric acid solution is 5%~20%, and the mass concentration of the sulfuric acid solution is 2%~35%.

3. The assay method according to claim 1, characterized by, The temperature of the first acidic solution is 0~10℃.

4. The assay method according to claim 1, characterized by, The temperature of the soaking treatment is 0~40℃, and the time of the soaking treatment is 20~80s.

5. The assay method according to claim 1, characterized by, In the step S2, the temperature of the second acidic solution is 0~10℃; the second acidic solution comprises at least one of a hydrochloric acid solution or a sulfuric acid solution, the mass concentration of the hydrochloric acid solution is 10%~20%, and the mass concentration of the sulfuric acid solution is 15%~35%.

6. The assay method according to claim 1, characterized by, The step S2 further comprises: Step S21, after immersing the aluminum plastic film in the first acidic solution for soaking treatment, taking out the undissolved nylon layer and the undissolved polypropylene layer from the first acidic solution to obtain a nylon layer to be cleaned and a polypropylene layer to be cleaned; Step S22, sequentially washing and air-drying the nylon layer to be cleaned and the polypropylene layer to be cleaned respectively to obtain the nylon layer and the polypropylene layer.

7. The assay method according to claim 6, characterized in that, The step S2 further comprises step S20, which immerses the aluminum plastic film in water and air-dries before performing the step S21; the temperature of the immersion in water is 40~50℃, and the time is 6~9h.

8. The assay method of claim 1, wherein The distance between any two non-adjacent points on the surface of the aluminum plastic film is 0.3~6.0cm.

9. The assay method of claim 1, wherein The area of the aluminum laminate film is 1 to 33 cm 2 .

10. The assay method according to any one of claims 1 to 9, characterized in that, The tools for measuring in the step S1 and the step S3 comprise a micrometer or a micrometer.

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