Pole roll protective film and isolation effect determination method thereof

Abstract

The invention relates to a pole roll protection film and an isolation effect determination method thereof, and relates to the technical field of pole roll processing and transportation. The pole roll protective film at least comprises an inner bonding layer, an aluminum layer and an outer protective layer, and the aluminum layer is arranged between the inner bonding layer and the outer protective layer. And the thickness of the pole roll protective film is set to be t which is more than or equal to 150 microns and less than or equal to 220 microns. According to the pole roll protection film, the sealing protection effect on the pole roll can be improved in the pole roll transportation process, and water vapor permeating into the pole roll in the transportation process is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of pole coil processing and transportation, and in particular, to a pole coil protective film and a method for determining its isolation effect. Background Art

[0002] In the process of power battery production and processing, the transportation and processing of pole coils is an important part. As a key component of the battery cell, the water content of the pole coil is an important factor affecting the quality of the battery cell. When the water content of the pole coil is too high, it will affect the capacity and energy density of the battery cell.

[0003] During the production, processing, transportation and storage of the pole rolls, water vapor will penetrate into the pole rolls, causing the water content of the pole rolls to increase. In order to protect the pole rolls and reduce the infiltration of water vapor, it is usually necessary to wrap a layer of protective film on the outside of the pole rolls during transportation. In specific use, the protective film is usually set to be made of materials such as aluminum plastic film. However, protective films of different materials and thicknesses will have different effects on the amount of water vapor infiltration during the wrapping and protection process. At the same time, as the transportation time increases, the amount of water vapor infiltration will also change. Therefore, different protective films need to be determined based on the transportation time and the water content requirements of the pole rolls. Summary of the invention

[0004] The purpose of the present application is to provide a pole roll protective film and a method for determining its isolation effect, wherein the pole roll protective film can improve the sealing protection effect of the pole roll during the pole roll transportation process and reduce the water vapor that penetrates into the pole roll during the transportation process.

[0005] In order to achieve the above-mentioned purpose, according to the first aspect of the present application, an embodiment of the present application provides a pole roll protection film, which at least includes an inner bonding layer, an aluminum layer and an outer protective layer, wherein the aluminum layer is arranged between the inner bonding layer and the outer protective layer. And the thickness of the pole roll protection film is set to t, 150μm≤t≤220μm.

[0006] Based on the above-mentioned embodiments of the present application, when the pole roll protective film is set, the different characteristics of the three-layer structure are combined to finally achieve the puncture resistance, corrosion resistance, good insulation and barrier properties of the pole roll protective film. At the same time, the limitation of the thickness of the pole roll protective film, on the one hand, makes the overall thickness of the pole roll protective film within a certain range, ensuring the overall strength of the pole roll protective film and other puncture resistance properties. On the other hand, it also leaves a certain range of space for the thickness setting of each layer structure, so as to make full use of the characteristics of each layer structure, and finally improve the overall performance of the pole roll protective film.

[0007] In some embodiments, the aluminum layer has a thickness t2, 5 μm≤t2≤100 μm.

[0008] Based on the above embodiments of the present application, the thickness of the aluminum layer is limited, and based on the highly dense metal crystal structure of the aluminum layer, the aluminum layer is mainly used as a barrier layer in the pole coil protective film by utilizing its high barrier properties, high strength and good ductility. Therefore, by ensuring the thickness of the aluminum layer, the barrier effect of the pole coil protective film as a whole is ensured, thereby reducing the amount of water vapor infiltration when protecting the pole coil.

[0009] In some embodiments, the inner bonding layer is configured as a polyamide layer and a chlorinated polyethylene layer, or the inner bonding layer is configured as a chlorinated polypropylene layer and adipic acid dihydrazide layer.

[0010] Based on the above-mentioned embodiments of the present application, the specific material of the inner adhesive layer can be any suitable material. When the inner adhesive layer is specifically set to a double-layer structure composed of a polyamide layer and a chlorinated polyethylene layer, on the one hand, the good corrosion resistance, electromagnetic shielding and high strength of polyamide are utilized, while the good heat and oxygen aging resistance, acid and alkali resistance and high filling properties of chlorinated polyethylene are combined, so that the pole roll protection film can be better adhered to and bonded with the pole roll when used for pole roll protection, and at the same time, the corrosion and aging damage process of the pole roll can be delayed during transportation and storage. Similarly, when the inner adhesive layer is set to a double-layer structure of a chlorinated polypropylene layer and adipic acid dihydrazide layer, the characteristics of the two materials are also used to improve the overall performance of the inner adhesive layer and the pole roll protection film.

[0011] In some embodiments, the inner bonding layer has a thickness t1, 80 μm≤t1≤180 μm.

[0012] Based on the above-mentioned embodiments of the present application, by limiting the thickness of the inner bonding layer, if the thickness of the inner bonding layer is too thick, it may affect the thickness setting of other layer structures, while if the thickness of the inner bonding layer is too thin, it will affect the performance of the inner bonding layer itself.

[0013] In some embodiments, the outer protective layer is configured as a polyester layer. Alternatively, the outer protective layer is configured as a polyester layer and a polyamide layer.

[0014] Based on the above embodiments of the present application, the outer protective layer can also be made of any suitable material. When the outer protective layer is set as a polyester layer, the polyester layer is used to protect the internal aluminum layer and other structures by using its high temperature resistance and good transparency. Similarly, when the outer protective layer is set as a double-layer structure of a polyester layer and a polyamide layer, the two materials are used to improve the overall performance of the outer protective layer to protect the inner aluminum layer and other structures.

[0015] In some embodiments, the thickness of the outer protective layer of the pole roll protective film is set to t3, 10 μm≤t3≤30 μm.

[0016] Based on the above-mentioned embodiments of the present application, by limiting the thickness of the outer protective layer, the protective effect of the outer protective layer is ensured without affecting other layers.

[0017] According to the second aspect of the present application, a method for determining the isolation effect of a pole roll protective film is provided. The method for determining the isolation effect of a pole roll protective film is applicable to the above-mentioned pole roll protective film, and the method for determining the isolation effect of a pole roll protective film comprises the following steps: encapsulating and protecting the pole roll with the pole roll protective film. During the encapsulation process, the sealing thickness T, the sealing length L, the sealing width W of the pole roll protective film, and the encapsulation surface area S of the pole roll protective film in the encapsulation structure are measured respectively. The amount of water vapor infiltration M of the pole roll after encapsulation for a certain period of time is measured, and then the isolation effect coefficient A of the pole roll protective film is determined according to the following formula (1):

[0018]

[0019] Based on the above-mentioned embodiments of the present application, through the above-mentioned steps, when factors such as the seal thickness T during pole roll packaging are determined, the protective effect of the pole roll protective film is determined by measuring the amount of water vapor penetration M of the pole roll after a certain period of time, and the calculated isolation effect coefficient A is used to represent the isolation effect of the pole roll protective film.

[0020] In some embodiments, the sealing thickness T of the pole roll protective film is determined according to the following formula (2):

[0021] Formula (2): (0.2t1+t2+t3)*2≤T≤(t1+t2+t3)*2.2.

[0022] Based on the above-mentioned embodiment of the present application, the sealing thickness T when sealing the pole roll is determined according to the thickness of different layer structures in the pole roll protective film through formula (2).

[0023] In some embodiments, the water vapor permeation of the pole roll is M, M≤780 mg.

[0024] Based on the above-mentioned embodiments of the present application, the amount of water vapor infiltration M of the pole roll directly affects the quality of the pole roll. By limiting the amount of water vapor infiltration M of the pole roll, the quality of the pole roll after production and processing is guaranteed. At the same time, when packaging and protecting the pole roll, the appropriate pole roll protective film material can be selected according to the above-mentioned requirements.

[0025] In some embodiments, in the step of encapsulating and protecting the pole coil by the pole coil protection film, the pole coil is set to a fixed volume and mass.

[0026] Based on the above-mentioned embodiments of the present application, the pole coil is set to a fixed volume and mass during detection to further control variables and improve the accuracy of detection.

[0027] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present application but do not constitute a limitation to the present application. In the accompanying drawings:

[0029] Figure 1 It is a cross-sectional schematic diagram of the pole roll protective film provided in an embodiment of the present application.

[0030] Description of Reference Numerals

[0031] 1. Inner bonding layer; 2. Aluminum layer; 3. Outer protective layer. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0036] In the description of this application, it should be noted that, in the absence of any contrary explanation, the terms "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0037] In the description of this application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the process of power battery production and processing, the transportation and processing of pole coils is an important part. As a key component of the battery cell, the water content of the pole coil is an important factor affecting the quality of the battery cell. When the water content of the pole coil is too high, it will affect the capacity and energy density of the battery cell.

[0039] During the production, processing, transportation and storage of the pole rolls, water vapor will penetrate into the pole rolls, causing the water content of the pole rolls to increase. In order to protect the pole rolls and reduce the infiltration of water vapor, it is usually necessary to wrap a layer of protective film around the outside of the pole rolls during transportation. In specific use, the protective film is usually set to be made of aluminum-plastic film and other materials. However, protective films of different materials and thicknesses will have different effects on the amount of water vapor infiltration during the wrapping and protection process. At the same time, with the extension of transportation time, such as in scenarios such as cross-border trade, the storage time of the pole rolls' transport boxes is extended. At this time, the amount of water vapor infiltration into the pole rolls will also change. Therefore, it is also necessary to determine different protective films based on the transportation time and the water content requirements of the pole rolls to ensure that the water content of the pole rolls can meet the requirements and avoid the pole rolls being unqualified due to water vapor infiltration during transportation and storage.

[0040] In order to solve the above problems in the prior art, according to the first aspect of the present application, reference is made to Figure 1 As shown in the figure, a pole roll protective film is provided, which is provided with at least three layers, and the pole roll protective film at least includes an inner bonding layer 1, an aluminum layer 2 and an outer protective layer 3, and the aluminum layer 2 is provided between the inner bonding layer 1 and the outer protective layer 3. The thickness of the pole roll protective film is set to t, 150μm≤t≤220μm.

[0041] Based on the above-mentioned embodiments of the present application, when the pole roll protective film is set, the different characteristics of the three-layer structure are combined to finally achieve the puncture resistance, corrosion resistance, good insulation and barrier properties of the pole roll protective film. At the same time, the setting of the thickness of the pole roll protective film, on the one hand, makes the overall thickness of the pole roll protective film within a certain range, ensuring the overall strength and other properties of the pole roll protective film. On the other hand, it also leaves a certain range of space for the thickness setting of each layer structure, so as to make full use of the characteristics of each layer structure, and finally improve the overall performance of the pole roll protective film.

[0042] Specifically, in the pole roll protective film, a three-layer structure of an inner bonding layer 1, an aluminum layer 2 and an outer protective layer 3 is set. The outer protective layer 3 arranged on the outermost side is mainly used to protect the inner aluminum layer 2 to prevent the aluminum layer 2 from being scratched and damaged. Therefore, the outer protective layer 3 is mainly required to meet good puncture resistance and impact resistance when being set.

[0043] Secondly, the aluminum layer 2 disposed between the outer protective layer 3 and the inner adhesive layer 1 mainly plays a barrier role to block the penetration of water vapor and oxygen to prevent the internal protective content from getting damp or oxidized. Therefore, the aluminum layer 2 needs to meet high barrier properties when it is disposed.

[0044] Finally, the inner bonding layer 1 arranged on the innermost side, on the one hand, plays the role of insulating and isolating the aluminum layer 2 from the internal protective content, and on the other hand, it also needs to protect the aluminum layer 2 to prevent the internal protective content from leaking and corroding the aluminum layer 2. Therefore, the inner bonding layer 1 needs to meet good insulation, corrosion resistance and heat sealing adhesion when being arranged.

[0045] Furthermore, by limiting the specific thickness of the pole coil protective film, pole coil protective films of different thicknesses correspond to different isolation and protection effects, and can be selected and set according to actual isolation and protection requirements and production and processing requirements, thereby reducing production costs while meeting use requirements.

[0046] Specifically, the thickness t of the pole roll protective film can be specifically set to values ​​such as 150 μm, 180 μm and 220 μm, and the present application does not impose any specific limitation on this.

[0047] In the case of meeting the above requirements, the inner adhesive layer 1 and the outer protective layer 3 in the present application can be set to any suitable material.

[0048] In an exemplary embodiment provided in the present application, the inner bonding layer 1 may be configured as a polyamide (PA) layer and a chlorinated polyethylene (CPE) layer, and the polyamide layer and the chlorinated polyethylene layer are sequentially configured to constitute the inner bonding layer 1 .

[0049] Based on the above-mentioned embodiments of the present application, any suitable material can be selected for the specific material of the inner adhesive layer 1. When the inner adhesive layer 1 is specifically configured as a double-layer structure consisting of a polyamide layer and a chlorinated polyethylene layer, on the one hand, the good corrosion resistance, electromagnetic shielding and high strength of polyamide are utilized, while the good heat and oxygen aging resistance, acid and alkali resistance and high filling properties of chlorinated polyethylene are combined, so that the pole coil protective film can be better adhered to the pole coil when used for pole coil protection, and at the same time, the aging and damage process of the pole coil can be delayed during transportation and storage.

[0050] Alternatively, in some other exemplary embodiments provided in the present application, the inner adhesive layer 1 can also be set as a double-layer structure of a chlorinated polypropylene (CPP) layer and an adipic dihydrazide (ADH) layer. In this case, the heat resistance, oxidation resistance and corrosion resistance of CPP are utilized on the one hand, and the good flexibility, corrosion resistance and insulation of adipic dihydrazide are utilized on the other hand, and the overall performance of the inner adhesive layer 1 and the pole roll protective film is improved through a double-layer structure composed of two materials.

[0051] Similarly, in an exemplary embodiment provided in the present application, the outer protective layer 3 may be provided with a polyester layer, such as a polyethylene terephthalate (PET) layer.

[0052] Based on the above-mentioned embodiments of the present application, the outer protective layer 3 is set as a polyester layer, and the high temperature resistance and good transparency of the polyester layer are utilized to protect the internal aluminum layer 2 and other structures.

[0053] Specifically, when the outer protective layer 3 is set as a polyethylene terephthalate layer, the good mechanical properties and barrier properties of polyethylene terephthalate itself are utilized, among which the mechanical properties are mainly reflected in its good impact resistance and folding resistance, and the high and low temperature environment has little effect on its mechanical properties. The barrier property is mainly reflected in its good barrier effect for gases, etc., and the permeability of gases and water vapor is low. Therefore, by setting the outer protective layer 3 as a polyethylene terephthalate layer, it is possible to achieve a good protection effect against mechanical impact, and strengthen the barrier effect of the pole roll protective film as a whole, reducing the amount of water vapor infiltration into the pole roll.

[0054] Alternatively, in some other embodiments provided in the present application, the outer protective layer 3 can also be set to a composite layer structure of a polyester layer and a polyamide layer.

[0055] Based on the above-mentioned embodiments of the present application, the outer protective layer 3 is set as a composite structure of a polyester layer and a polyamide layer, and the high temperature resistance, good mechanical properties and barrier properties of the polyester layer are utilized. On this basis, another polyamide layer is set, and the good corrosion resistance, electromagnetic shielding and high strength of the polyamide layer are utilized to further enhance the strength and isolation protection effect of the outer protective layer 3.

[0056] In summary, the inner adhesive layer 1 and the outer protective layer 3 in the present application can be set to any suitable material during the specific production and processing process, and the present application does not make any specific restrictions on this.

[0057] In addition, it should be noted that in the present application, an aluminum layer 2 is provided between the inner adhesive layer 1 and the outer protective layer 3. In this case, the pole coil protective film is provided as an aluminum-plastic film, and the aluminum layer 2 can be provided as an aluminum foil structure.

[0058] Furthermore, in the present application, the thicknesses of the inner bonding layer 1 , the aluminum layer 2 , and the outer protective layer 3 may also be selected within any appropriate range.

[0059] In an exemplary embodiment provided in the present application, the thickness of the inner adhesive layer 1 is t1, wherein the specific numerical range of t1 can be set to 80 μm≤t1≤180 μm.

[0060] Based on the above-mentioned embodiments of the present application, by limiting the specific thickness range of the inner adhesive layer 1, when the thickness of the inner adhesive layer 1 is too thick, it may affect the thickness setting of other layer structures, and then affect the performance of other layer structures, while when the thickness of the inner adhesive layer 1 is too thin, it will affect the performance of the inner adhesive layer 1 itself.

[0061] Specifically, the thickness t1 of the inner adhesive layer 1 can be specifically set to values ​​such as 80 μm, 120 μm, and 180 μm, and the thickness of each layer inside the inner adhesive layer 1 can be specifically divided according to the thickness of the inner adhesive layer 1. For example, when the thickness of the inner adhesive layer 1 is set to 180 μm, and the inner adhesive layer 1 includes a polyamide layer and a chlorinated polyethylene layer, the thickness of the polyamide layer can be set to 15 μm, and the thickness of the chlorinated polyethylene layer can be set to 165 μm. Any suitable thickness range can be selected in specific production and processing, and this application does not make specific restrictions on this.

[0062] In an exemplary embodiment provided in the present application, the thickness of the aluminum layer 2 is set to t2, wherein the specific value range of t2 can be set to 5 μm≤t2≤100 μm.

[0063] Based on the above-mentioned embodiments of the present application, by limiting the thickness of the aluminum layer 2, the aluminum layer 2 is mainly used as a barrier layer in the pole coil protective film by utilizing the highly dense metal crystal structure, high barrier property, high strength and good ductility of the aluminum layer 2. Therefore, by ensuring the thickness of the aluminum layer 2, the barrier effect of the pole coil protective film as a whole is ensured, thereby reducing the amount of water vapor penetration when protecting the pole coil.

[0064] Specifically, the thickness t2 of the aluminum layer 2 can be set to values ​​such as 5 μm, 7 μm, 15 μm, 40 μm and 100 μm.

[0065] Furthermore, in order to verify the influence of the thickness of the aluminum layer 2 on the isolation effect of the pole roll protective film, the present application conducted the following experiment. Three different pole roll protective films were selected for the experiment. The difference between the three pole roll protective films lies in the different thickness of the aluminum layer 2. The same volume of the same pole roll was sealed with the same sealing method using three different pole roll protective films. After a certain period of time, the moisture content of the pole rolls sealed by the three pole roll protective films was measured, and the experimental data obtained are recorded in the following table.

[0066] Among them, the thickness of the aluminum layer 2 in the pole roll protection film 1 is 15 μm, the thickness of the aluminum layer 2 in the pole roll protection film 2 is 40 μm, and the thickness of the aluminum layer 2 in the pole roll protection film 3 is 7 μm.

[0067] Pole roll protective film 1 Pole roll protective film 2 Pole roll protective film 3 Example 1 615.08 158.61 825.71 Example 2 577.4 153.71 866.17 Example 3 558.24 200.56 824.95 Example 4 406.79 203.68 782.94 Example 5 397.98 201.89 841.48 average value 511.098 183.69 828.25

[0068] From the data recorded in the table, it can be seen that among the three types of pole roll protective films, the water content of the pole roll increases the least when the pole roll protective film 2 with an aluminum layer 2 thickness of 40 μm is selected for sealing, and the water content of the pole roll increases the most when the pole roll protective film 3 with an aluminum layer 2 thickness of 7 μm is selected for sealing.

[0069] Based on the above-mentioned embodiments of the present application, the isolation and protection effect of the pole roll protective film is enhanced by increasing the thickness of the aluminum layer 2 inside the pole roll protective film, and the amount of water vapor penetrating into the pole roll is reduced when the pole roll is sealed. The moisture content of the pole roll after sealing is reduced by setting a thicker aluminum layer 2 in the pole roll protective film, thereby improving the quality of the pole roll.

[0070] In addition, it should be noted that the above embodiment specifically measures the water vapor infiltration amount M of the pole roll. In specific detection, the water content ppm ratio of the pole roll can also be obtained based on the ratio of the water vapor infiltration amount M of the pole roll to the mass of the pole roll.

[0071] In some exemplary embodiments provided in the present application, the thickness of the outer protective layer 3 is set to t3, wherein the specific value range of t3 can be set to 10 μm≤t3≤30 μm.

[0072] Based on the above-mentioned embodiments of the present application, by limiting the thickness of the outer protective layer 3, the protective effect of the outer protective layer 3 is ensured without affecting other layers.

[0073] Specifically, the thickness t3 of the outer protective layer 3 can be specifically set to values ​​such as 10 μm, 21 μm, and 30 μm, and the thickness of each layer inside can be specifically divided according to the thickness of the outer protective layer 3. For example, when the thickness t3 of the outer protective layer 3 is set to 21 μm, and the outer protective layer 3 is set to a double-layer structure of a polyester layer and a polyamide layer, the polyester layer can be set to 6 μm, and the polyamide layer can be set to 15 μm. Any suitable thickness range can be selected in specific production and processing, and this application does not impose specific restrictions on this.

[0074] On the basis of the above technical solution, according to the second aspect of the present application, a method for determining the isolation effect of a pole roll protective film is provided, and the method for determining the isolation effect of a pole roll protective film is applicable to the above pole roll protective film, and the method for determining the isolation effect of a pole roll protective film comprises the following steps: encapsulating and protecting the pole roll with a pole roll protective film. During the encapsulation process, the sealing thickness T, the sealing length L, the sealing width W of the pole roll protective film, and the encapsulation surface area S of the pole roll protective film in the encapsulation structure are measured respectively. The amount of water vapor infiltration M of the pole roll after a certain period of encapsulation is measured, and then the isolation effect coefficient A of the pole roll protective film is determined according to the following formula (1):

[0075]

[0076] Based on the above-mentioned embodiments of the present application, through the above-mentioned steps, when factors such as the seal thickness T during pole roll packaging are determined, the protective effect of the pole roll protective film is determined by measuring the amount of water vapor penetration M of the pole roll after a certain period of time, and the calculated isolation effect coefficient A is used to represent the isolation effect of the pole roll protective film.

[0077] Specifically, in the above steps, the seal thickness T, seal length L, seal width W and packaging surface area S of the pole roll protection when the pole roll is sealed and protected may affect the water vapor penetration M of the pole roll. Therefore, by setting the above-mentioned influencing factors to fixed values, the water vapor penetration M of the pole roll is measured after a certain period of time, that is, the isolation effect coefficient A of the corresponding pole roll protection film is obtained by controlling the variables, which is used to represent the isolation effect of the pole roll protection film when isolating the pole roll.

[0078] At the same time, in the process of specific measurement, multiple sets of data can be measured for the same pole roll protective film while setting various conditions such as the sealing thickness T unchanged, and then the accuracy of the measurement can be further improved by taking the average value.

[0079] At the same time, since the above measurement process is to measure the water vapor penetration M of the pole roll after a certain period of time, corresponding to the same pole roll protective film, the water vapor penetration M of the pole roll after different times can also be measured when factors such as the sealing thickness T remain unchanged, and then the protective effect of the pole roll protective film after different times can be determined.

[0080] Furthermore, by determining the isolation effect coefficient A of pole coil protective films of different thicknesses and different materials, in actual use, a suitable pole coil protective film can be selected according to factors such as the transportation and storage time of different pole coils, and the sealing structure.

[0081] Furthermore, in some embodiments of the present application, the sealing thickness T of the pole coil protective film can also be determined according to the following formula (2):

[0082] Formula (2): (0.2t1+t2+t3)*2≤T≤(t1+t2+t3)*2.2.

[0083] Based on the above-mentioned embodiment of the present application, the sealing thickness T when sealing the pole roll is determined according to the thickness of different layer structures in the pole roll protective film through formula (2).

[0084] Furthermore, for pole roll protective films of different thicknesses and materials, the corresponding layer structure thicknesses can be substituted into formula (2) to obtain the numerical range of the sealing thickness T of the corresponding pole roll protective film, thereby setting different sealing structures according to different pole roll protective films, thereby further improving the isolation and protection effect of the pole roll.

[0085] In some embodiments, the water vapor permeation of the pole roll is M, M≤780 mg.

[0086] Based on the above-mentioned embodiments of the present application, the amount of water vapor infiltration M of the pole roll directly affects the quality of the pole roll. By limiting the amount of water vapor infiltration M of the pole roll, the quality of the pole roll is guaranteed. At the same time, when packaging and protecting the pole roll, the appropriate pole roll protective film material can be selected according to the above-mentioned requirements.

[0087] Specifically, the water vapor penetration amount M of the pole roll can be set to specific values ​​such as 600 mg, 700 mg and 780 mg. The corresponding water content requirement can be determined according to the quality requirements of the pole roll, and this application does not make any specific restrictions on this.

[0088] In some embodiments of the present application, in the step of encapsulating and protecting the pole coil by the pole coil protection film, the pole coil is set to a fixed volume and mass.

[0089] Based on the above-mentioned embodiments of the present application, the pole coil is set to a fixed volume and mass during detection to further control variables and improve the accuracy of detection.

[0090] The preferred embodiments of the present application are described in detail above in conjunction with the accompanying drawings; however, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the protection scope of the present application.

[0091] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not further describe various possible combinations.

[0092] In addition, the various implementation modes of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the contents disclosed in the present application.

Claims

1. A pole roll protective film, characterized in that: The pole roll protective film is provided with at least three layers, and the pole roll protective film at least comprises: Inner adhesive layer and outer protective layer; an aluminum layer, the aluminum layer being disposed between the inner bonding layer and the outer protective layer; Wherein, the thickness of the pole roll protective film is set to t, 150μm≤t≤220μm.

2. The pole roll protective film according to claim 1, characterized in that: The thickness of the aluminum layer is t2, 5μm≤t2≤100μm.

3. The pole roll protective film according to claim 1, characterized in that: The inner adhesive layer is provided with a polyamide layer and a chlorinated polyethylene layer; or, The inner bonding layer is configured as a chlorinated polypropylene layer and adipic acid dihydrazide layer.

4. The pole roll protective film according to claim 3, characterized in that: The thickness of the inner bonding layer is t1, 80 μm≤t1≤180 μm.

5. The pole roll protective film according to claim 1, characterized in that: The outer protective layer is a polyester layer; or The outer protective layer is configured as a polyester layer and a polyamide layer.

6. The pole roll protective film according to claim 5, characterized in that: The thickness of the outer protective layer is set to t3, 10 μm≤t3≤30 μm.

7. A method for determining the isolation effect of a pole coil protective film, characterized in that: The method for determining the isolation effect of the pole roll protective film is applicable to the pole roll protective film according to any one of claims 1 to 6, and the method for determining the isolation effect of the pole roll protective film comprises the following steps: The pole coil is encapsulated and protected by a pole coil protective film; During the packaging process, the sealing thickness T, the sealing length L, the sealing width W and the packaging surface area S of the pole roll protective film in the packaging structure are measured respectively; The water vapor penetration M of the pole coil after a certain period of packaging is measured, and then the isolation effect coefficient A of the pole coil protective film is determined according to the following formula (1):

8. The method for determining the isolation effect of the pole coil protective film according to claim 7, characterized in that: The sealing thickness T of the pole coil protective film is determined according to the following formula (2): Formula (2): (0.2t1+t2+t3)*2≤T≤(t1+t2+t3)*2.

2.

9. The method for determining the isolation effect of the pole coil protective film according to claim 7, characterized in that: The water vapor penetration amount M of the pole roll is M≤780mg.

10. The method for determining the isolation effect of the pole coil protective film according to claim 7, characterized in that: In the step of encapsulating and protecting the pole coil by the pole coil protection film, the pole coil is set to a fixed volume and mass.

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