Method for measuring amount of oil on aluminum foil

Abstract

Disclosed in the present application is a method for measuring the amount of oil on aluminum foil. Said method comprises: acquiring initial weights of a plurality of groups of aluminum foil pieces, the plurality of groups of aluminum foil pieces being obtained by cutting aluminum foil to be measured; determining a target heating mode for the plurality of groups of aluminum foil pieces on the basis of an oil amount changing relationship, and, according to the target heating mode, controlling a heating appliance to heat the plurality of groups of aluminum foil pieces, the oil amount changing relationship comprising the amounts of oil, under a plurality of heating modes, on at least one aluminum foil piece which is obtained by means of carbon coating; acquiring target weights of the plurality of groups of aluminum foil pieces after the heating; and on the basis of weight differences between the initial weights and the target weights, obtaining the amount of oil on said aluminum foil. The described solution can measure the amount of oil on the surfaces of aluminum foil.

Description

Method for detecting oil content in aluminum foil Cross-references

[0001] This application claims priority to Chinese Patent Application No. 202410931085.9, filed on July 11, 2024, entitled “Method for detecting oil content in aluminum foil”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of aluminum foil, and in particular to a method for detecting the oil content of aluminum foil. Background Technology

[0003] With the rapid development of the domestic electronics and electric vehicle industries, the demand for various types of batteries has increased rapidly, and the demand for related products has also increased accordingly, with aluminum foil being one of them. Aluminum foil has been widely used in recent years. It is typically rolled and then directly cut into coating specifications. The surface of the finely rolled aluminum foil contains a certain amount of oil (oil film). The amount of oil affects the energy storage performance of the battery after lithium battery material coating. When the overall oil content on the aluminum foil surface is large (thick oil film), the adhesion of the coating material is poor, resulting in a thin or uneven coating, which affects the battery's energy storage capacity.

[0004] Currently, the industry primarily uses dyne values ​​to characterize the surface energy of aluminum foil and evaluate its coating effect. A higher dyne value indicates a greater surface energy and a better coating effect. The dyne value of aluminum foil is influenced by the characteristics of the surface oil, the processing method, and the amount of oil carried. After years of development, the lithium-ion battery foil industry, using dyne value as a technical control indicator, has developed rolling oils with high ester additives. This produces aluminum foil with high dyne values ​​and thick oil films, resulting in high surface energy but also high oil content. While the aluminum foil meets technical requirements, it does not meet production requirements. Therefore, a method for detecting the amount of oil carried on the aluminum foil surface is needed. Summary of the Invention

[0005] This application provides at least one method for detecting the amount of oil on aluminum foil to achieve the detection of the amount of oil on the surface of aluminum foil.

[0006] This application provides a method for detecting the oil content of aluminum foil. The method includes: obtaining the initial weight of several sets of aluminum foil sheets, which are cut from aluminum foil to be tested; determining the target heating method for the several sets of aluminum foil sheets based on the oil content variation relationship, and controlling a heating device to heat the several sets of aluminum foil sheets according to the target heating method, wherein the oil content variation relationship includes the oil content of aluminum foil sheets obtained by at least one carbonization method under multiple heating methods; obtaining the target weight of the several sets of aluminum foil sheets after heating; and obtaining the oil content of the aluminum foil to be tested based on the weight difference between the initial weight and the target weight.

[0007] In the above scheme, several groups of aluminum foil sheets are first obtained from the aluminum foil to be tested. The heating method of the several groups of aluminum foil sheets is determined by the pre-obtained oil content change relationship. The weight difference of the several groups of aluminum foil sheets before and after heating can be used to determine the weight of the volatilized oil, thereby determining the oil content of the several groups of aluminum foil sheets and estimating the oil content of the aluminum foil sheet to be tested.

[0008] In some embodiments, the method for detecting the oil content of aluminum foil further includes: obtaining the oil content of aluminum foil sheets obtained by different carbonization methods under multiple heating methods, wherein the heating methods include at least one or more of the following heating parameters: heating time, heating temperature, and the placement method of several groups of aluminum foil sheets in the heating appliance, wherein at least one heating parameter in different heating methods is different; and obtaining the oil content variation relationship based on the oil content of aluminum foil sheets obtained by each carbonization method under multiple heating methods.

[0009] In the above scheme, by obtaining the amount of oil carried by aluminum foil sheets obtained by different carbon coating methods under various heating methods, the appropriate target heating method can be determined based on the relationship of oil carry-over changes, so that the weight change between the heated weight and the initial weight is more obvious, thus facilitating the calculation of the corresponding oil carry-over amount.

[0010] In some embodiments, the carbon coating method includes incomplete coating and non-incomplete coating. The oil content variation relationship includes the first oil content variation of the aluminum foil obtained by incomplete coating under various heating methods and the second oil content variation of the aluminum foil obtained by non-incomplete coating under various heating methods. Based on the oil content variation relationship, the target heating method for several groups of aluminum foils is determined, including: determining the first heating method corresponding to the maximum oil content in the first oil content variation and determining the second heating method corresponding to the maximum oil content in the second oil content variation; and determining the target heating method based on the first heating method and the second heating method.

[0011] In the above scheme, the first and second changes in oil content are determined by using aluminum foil obtained by both missing and non-missing coating methods, so as to determine the first and second heating methods. Then, the target heating method is comprehensively considered by referring to the heating methods under the two carbon coating methods, so that the determined target heating method is more accurate.

[0012] In some embodiments, determining a target heating method based on a first heating method and a second heating method includes: in response to the first heating method being the same as the second heating method, using either the first heating method or the second heating method as the target heating method; or, in response to the first heating method being different from the second heating method, determining the weights of the first heating method and the second heating method, and performing weighted fusion of at least one heating parameter in the first heating method and the second heating method according to the weights to obtain the target heating method.

[0013] In the above scheme, if the two heating methods are the same, one of them is directly determined as the target heating method. If the two heating methods are different, a more suitable target heating method can be determined by referring to the first heating method and the second heating method.

[0014] In some embodiments, the heating appliance has a first accommodating space for placing a plurality of aluminum foil sheets. Controlling the heating appliance to heat the plurality of aluminum foil sheets according to a target heating method includes: gradually heating the temperature of the first accommodating space in the heating appliance containing the plurality of aluminum foil sheets to a target temperature within a first preset time period; and continuously heating to the target temperature for a second preset time period, wherein the first preset time period is shorter than the second preset time period.

[0015] In the above scheme, by setting a relatively short heating time and a relatively long holding time, the oil on the aluminum foil surface can be ensured to burn more completely, thereby making the amount of oil on the filter surface to be tested more accurate.

[0016] In some embodiments, the heating appliance includes a first accommodating space for placing a plurality of groups of aluminum foil sheets. Controlling the heating appliance to heat the plurality of groups of aluminum foil sheets according to a target heating method includes: placing different groups of aluminum foil sheets into different second accommodating spaces in a heating bracket, each second accommodating space being independently set in the heating bracket, wherein each group of aluminum foil sheets is divided according to the acquisition time; and placing the heating bracket in the first accommodating space of the heating appliance to heat each group of aluminum foil sheets in the heating bracket.

[0017] In the above solution, by placing different groups of aluminum foil sheets in different compartments within the heating bracket, this solution ensures that the oil on the surface of the aluminum foil sheets can evaporate more fully compared to stacking the aluminum foil sheets together.

[0018] In some embodiments, the second receiving space includes a through slot formed by a plurality of sidewalls for placing groups of aluminum foil sheets.

[0019] In the above scheme, by setting the accommodating space as a through groove formed by several side walls, and placing each group of aluminum foil sheets in the corresponding through groove, the evaporation efficiency of the oil on the surface of each aluminum foil sheet can be improved compared to a closed or semi-closed accommodating space.

[0020] In some embodiments, the aluminum foil to be tested is an aluminum roll formed by winding, and the method further includes: obtaining multiple layers of target aluminum foil in the aluminum foil to be tested; obtaining multiple aluminum foil sheets from the central region of each layer of target aluminum foil; and grouping the aluminum foil sheets to obtain several groups of aluminum foil sheets.

[0021] In the above scheme, multiple target aluminum foils are first obtained from the aluminum coil, and multiple aluminum foil sheets are obtained from the central area of ​​each target aluminum foil. Then, the obtained aluminum foil sheets are grouped to obtain several groups of aluminum foil sheets, which reduces the interference of the potentially contaminated area at the edge of each target aluminum foil on the detection of oil quantity, thereby ensuring the accuracy of the detection of oil quantity of the aluminum foil to be detected.

[0022] In some embodiments, the aluminum foil sheets are grouped to obtain several groups of aluminum foil sheets, including: for each target aluminum foil layer, multiple aluminum foil sheets obtained from the target aluminum foil are stacked to obtain at least one stack of aluminum foil sheets corresponding to the target aluminum foil; the aluminum foil sheets in the top layer and the bottom layer of the stack of aluminum foil sheets are discarded respectively; the multiple stacks of aluminum foil sheets are combined to obtain a group of aluminum foil sheets, thus obtaining several groups of aluminum foil sheets.

[0023] In the above scheme, after obtaining multiple stacks of aluminum foil, the top and bottom layers of aluminum foil that may be contaminated are discarded before being combined into several groups of aluminum foil, which can ensure the accuracy of the detection of the amount of oil in the aluminum foil to be tested.

[0024] In some embodiments, the amount of oil carried by the aluminum foil to be tested is obtained based on the weight difference between the initial weight and the target weight, including: obtaining the ratio between the weight difference and the initial weight; determining a first product of the ratio and the thickness of a plurality of aluminum foil sheets; multiplying the first product by the density of the aluminum foil sheets to obtain a second product as the amount of oil carried by the plurality of aluminum foil sheets, and the amount of oil carried by the plurality of aluminum foil sheets as the amount of oil carried by the aluminum foil to be tested.

[0025] In the above scheme, by considering the thickness and density of several aluminum foil sheets, the amount of oil on the surface of the aluminum foil sheet per unit weight can be determined.

[0026] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this application. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application.

[0028] Figure 1 is a flowchart illustrating a method for detecting the oil content of aluminum foil according to some embodiments of this application;

[0029] Figure 2 is a schematic diagram of the oil content variation relationship in the oil content detection method of aluminum foil provided in some embodiments of this application;

[0030] Figure 3 is a schematic diagram of the structure of the heating bracket in the method for detecting the oil content of aluminum foil provided in some embodiments of this application;

[0031] Figure 4 is a schematic diagram of the cutting method of the central region of the target aluminum foil in the method for detecting the amount of oil on aluminum foil provided in some embodiments of this application;

[0032] Figure 5 is a graph of the variation components in the R&R report of the method for detecting the oil content of aluminum foil provided in some embodiments of this application;

[0033] Figure 6 is a graph showing the oil content multiplied by the sample number (experimenter) in the R&R report of the oil content detection method for aluminum foil provided in some embodiments of this application;

[0034] Figure 7 is an R control chart in the R&R report of the method for detecting the oil content of aluminum foil provided in some embodiments of this application;

[0035] Figure 8 is an Xbar control chart in the R&R report of the method for detecting the oil content of aluminum foil provided in some embodiments of this application;

[0036] Figure 9 is a graph showing the oil content multiplied by the experimenter in the R&R report of the oil content detection method for aluminum foil provided in some embodiments of this application;

[0037] Figure 10 is a schematic diagram comparing the amount of oil on aluminum foil in the oil content detection method provided in some embodiments of this application. Detailed Implementation

[0038] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0039] In the following description, specific details such as particular subsystem structures, interfaces, and technologies are presented for illustrative purposes rather than for limiting purposes, in order to provide a thorough understanding of this application.

[0040] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, "many" in this document means two or more. Moreover, the term "at least one" in this document means any combination of at least two of any one or more of a plurality of objects. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0041] For aluminum foil current collectors used in lithium-ion batteries, which are produced by rolling process and have rolling oil sprayed on the surface, there is currently no effective method to detect the residual amount of rolling oil when shipping. When the aluminum foil has too much oil, it will cause problems such as incomplete coating and decarburization when it is used for carbon coating. During electrode preparation, it may cause the active material to peel off from the aluminum foil or have insufficient adhesion, resulting in short circuit and low capacity of the cell.

[0042] Existing methods for detecting oil content on aluminum foil surfaces mainly rely on observing the time it takes for the oil film to evaporate or evaluating the degree of oiliness by smell. These methods have certain limitations, as they cannot be quantified. When the rolling oil is relatively clean, has a low oil content, or is relatively transparent, it is impossible to make an accurate judgment with the naked eye. Furthermore, the detection of the rolling oil odor is particularly dependent on human judgment and has poor repeatability.

[0043] To address this technical problem, this application involves cutting the aluminum foil to be tested into several sets of aluminum foil sheets. These sheets are then weighed before and after heating. Since oil evaporates at high temperatures, the amount of oil carried in the aluminum foil sheets before and after heating is determined based on the weight difference. This oil content is then used to determine the amount of oil carried in the aluminum foil to be tested. The method of this application is repeatable and can quantify the amount of oil on the aluminum foil surface.

[0044] Please refer to Figure 1. This application provides a method for detecting the oil content of aluminum foil, which may include the following steps S11 to S14. The method for detecting the oil content of aluminum foil includes: Step S11: Obtaining the initial weight of several sets of aluminum foil sheets. The several sets of aluminum foil sheets are cut from the aluminum foil to be tested. Step S12: Determining the target heating method for the several sets of aluminum foil sheets based on the oil content variation relationship, and controlling the heating device to heat the several sets of aluminum foil sheets according to the target heating method. The oil content variation relationship includes the oil content of aluminum foil sheets obtained by at least one carbonization method under multiple heating methods. Step S13: Obtaining the target weight of the several sets of aluminum foil sheets after heating. Step S14: Obtaining the oil content of the aluminum foil to be tested based on the weight difference between the initial weight and the target weight.

[0045] The oil on the surface of the aluminum foil to be tested is generally rolling oil. Alternatively, it can be obtained by cutting several sets of aluminum foil sheets using an automatic cutting system or manually. Any system with cutting capabilities can be used; no specific limitation is made here. The initial weight of the several sets of aluminum foil sheets can be the total weight of the several sets or the total weight of some sets. The "several sets" can be one or more sets, each containing multiple aluminum foil sheets. Because a single aluminum foil sheet is relatively light, this solution uses multiple aluminum foil sheets for oil content detection to improve accuracy. In some application scenarios, each set of aluminum foil sheets has an initial weight and a target weight. That is, each set of aluminum foil sheets determines its oil content based on its initial weight, target weight, thickness, and density. The maximum oil content of each set of aluminum foil sheets can be used as the oil content of the aluminum foil to be tested, or the average of the oil content can be used as the oil content of the aluminum foil to be tested. In some applications, several groups of aluminum foil sheets are weighed uniformly to obtain an initial weight and a target weight, thus determining the oil content. This oil content is directly used as the oil content of the aluminum foil to be tested. High-precision weighing tools can be selected; for example, several groups of aluminum foil sheets can be transferred to the weighing tool by means of a robotic arm or belt conveyor. The oil content variation relationship includes the oil content of aluminum foil sheets obtained by at least one carbonization method under various heating methods. Carbonization methods can be classified in various ways; for example, carbonization methods can include incomplete and complete carbonization, or different carbonization methods can be determined based on different carbonization tools, or different carbon compositions. In other words, different carbonization methods can be determined by comprehensively considering different factors. The oil content variation relationship can be the change in oil content of the aluminum foil sheets under various heating methods. Through this oil content variation relationship, the heating method with a relatively significant change in oil content can be identified as the target heating method for the aluminum foil sheets. The heating parameters included in the heating method can be any parameters that may affect the change in oil content. The heating appliance can be any device capable of outputting temperature, including but not limited to: muffle furnace, forced-air drying oven, vacuum furnace, and high-temperature oven. The environment within the heating appliance can be a vacuum environment or a non-vacuum environment. The placement of several sets of aluminum foil sheets in the heating appliance can be rolled, stacked, cut into pieces and then placed, or each set of aluminum foil sheets can be placed separately using a heating support. The method of heating several sets of aluminum foil sheets in the heating appliance can be to first place the several sets of aluminum foil sheets in the heating appliance and then gradually heat the temperature in the heating appliance to the target temperature, or to preheat the heating appliance first and then place the several sets of aluminum foil sheets in the heating appliance. Optionally, the target temperature is higher than the distillation point temperature of the rolling oil. That is, in this scheme, a temperature higher than the distillation point temperature of the rolling oil is used to bake several sets of aluminum foil sheets, causing the residual oil on the surface of the aluminum foil to evaporate under baking, thereby reducing the weight of the several sets of aluminum foil sheets.The amount of oil on the aluminum foil to be tested can be determined by measuring the weight changes of several sets of aluminum foil sheets.

[0046] In the above scheme, several groups of aluminum foil sheets are first obtained from the aluminum foil to be tested. The heating method of the several groups of aluminum foil sheets is determined by the pre-obtained oil content change relationship. The weight difference of the several groups of aluminum foil sheets before and after heating can be used to determine the weight of the volatilized oil, thereby determining the oil content of the several groups of aluminum foil sheets and estimating the oil content of the aluminum foil sheet to be tested.

[0047] In some embodiments, the method further includes: obtaining the oil content of aluminum foil sheets obtained by different carbonization methods under various heating methods. The heating methods include at least one or more of the following heating parameters: heating time, time required for temperature rise, heating temperature, cooling time, and the placement of several groups of aluminum foil sheets within a heating appliance. At least one heating parameter differs in different heating methods. Then, based on the oil content of the aluminum foil sheets obtained by each carbonization method under various heating methods, the relationship between oil content variations is obtained.

[0048] Considering that the direct cause of incomplete coating and powder shedding problems in the carbonization process of lithium-ion battery aluminum foil is excessive residual oil on the aluminum foil surface, this method collected aluminum foil with different carbonization effects and used different sample preparation methods (methods for obtaining aluminum foil for heating), heating temperatures, the time required to heat the heating device from room temperature to the target temperature, the time required to cool from the target temperature to room temperature or other cooling temperatures after heating, the time to maintain the heating temperature, and the placement of several groups of aluminum foil sheets in the heating device to test the changes in oil content during the heating process (baking process). Carbonization methods can be classified in various ways. For example, carbonization methods can include incomplete coating and non-incomplete coating, or different carbonization methods can be determined based on different carbonization tools, or different carbon compositions. In other words, different carbonization methods can be determined by comprehensively considering different factors. For ease of description, aluminum foil sheets obtained through different carbonization methods are referred to as sample aluminum foil sheets. Various product methods can be used to obtain aluminum foil sheets with different carbonization methods. Then, the oil content changes of different carbonization methods under various heating parameters are tested. Based on the oil content changes, the surface oil volatility and oxidation characteristics of the aluminum foil are extracted to determine the target heating method, such as heating time, heating temperature, or other heating parameters. Furthermore, the aluminum foil sample preparation method can be determined so that several groups of aluminum foil sheets can be obtained from the aluminum foil to be tested according to the target aluminum foil product method. Thus, based on the product method and heating parameters where the oil content changes significantly, the target product method and heating method are determined. For the product method, this includes determining how many grams of aluminum foil to be obtained from the aluminum foil to be tested each time, and from which area of ​​the aluminum foil to be tested. For example, the relationship of oil content change can be obtained as follows: With a fixed heating temperature of A, the oil content changes are tested under different heating times, different heating times, different cooling times, different placement methods of several groups of aluminum foil sheets in the heating appliance, or different aluminum foil sample preparation methods. Alternatively, by fixing the heating time as heating time B, the changes in oil content can be tested under different heating temperatures, different cooling times, or different placement methods of several groups of aluminum foil sheets in the heating appliance, or under different target aluminum foil product methods. In each test, only one parameter or a few parameters can be changed for easy observation. The oil content change relationship can be recorded under various test parameters, thereby determining the optimal heating parameters and product method.

[0049] The oil content can be the ratio between the weight difference of the sample aluminum foil before and after heating and the initial weight of the sample aluminum foil before heating, or it can simply represent the weight difference of the sample aluminum foil before and after heating. This embodiment uses the oil content per unit area of ​​aluminum foil as an example. The oil content variation relationship records the oil content of aluminum foil obtained according to different carbonization methods under different heating methods. The oil content variation relationship can be in the form of an oil content variation curve or a bar chart, etc. Based on the oil content variation relationship, a general heating method applicable to aluminum foil obtained by various carbonization methods can be determined as the target heating method. For example, the heating method corresponding to the maximum or obvious oil content among the multiple oil contents obtained by aluminum foil obtained by different carbonization methods under various heating methods can be merged to obtain the target heating method. Optionally, based on the oil content variation relationship, the specific method for obtaining several groups of aluminum foil from the aluminum foil to be tested can also be determined, such as how many grams are obtained each time as a group, how many groups are obtained in total, and from which position of the aluminum foil to be tested each group is obtained, etc. In some applications, the heating appliance is a muffle furnace. Several sets of aluminum foil sheets can be placed inside the muffle furnace, and the furnace is set to heat from room temperature to 300°C (heating time ≤ 35 min), and then baked for 1 hour after reaching 300°C. After baking for 1 hour, the furnace temperature is allowed to cool to approximately 150°C, and the several sets of aluminum foil sheets are removed. After the several sets of aluminum foil sheets have cooled to room temperature, the target weight is obtained.

[0050] In the above scheme, by obtaining the amount of oil carried by aluminum foil sheets obtained by different carbon coating methods under different heating methods, the appropriate target heating method can be determined based on the relationship of oil carry-over changes, so that the weight change between the heated weight and the initial weight is more obvious, thus facilitating the calculation of the corresponding oil carry-over amount.

[0051] In some embodiments, the coating method includes incomplete coating and non-incomplete coating, and the oil content variation relationship includes the first oil content variation of the aluminum foil obtained by incomplete coating under various heating methods and the second oil content variation of the aluminum foil obtained by non-incomplete coating under various heating methods. The method for determining the target heating method for several groups of aluminum foils based on the oil content variation relationship can be: determining the first heating method corresponding to the maximum oil content in the first oil content variation, and determining the second heating method corresponding to the maximum oil content in the second oil content variation. Based on the first heating method and the second heating method, the target heating method is determined.

[0052] "Missing coating" can be understood as areas on the aluminum foil surface where carbon coating is missing, while "no missing coating" can be understood as areas on the aluminum foil surface where carbon coating is absent or not detected. The first and second oil content variations refer to aluminum foil sheets prepared using the same sample preparation method but with different carbon coating methods. These two types of aluminum foil sheets were heated using different heating methods to obtain the oil content under different heating conditions. For example, the two types of aluminum foil sheets were placed in a heater at 300℃ for 0.5h, 1h, 2h, and 4h, respectively, resulting in two oil content variations, as shown in Figure 2. The aluminum foil with missing coating showed the highest oil content after heating for 1h, while the aluminum foil without missing coating also showed the highest oil content after heating for 1h. Therefore, 1h heating can be directly used as the heating duration in the target heating method. However, it is possible that under other carbon coating methods or other sample preparation methods, the two oil content variations might result in the highest oil content under the same heating method. Therefore, a fusion of heating methods can be used to determine the target heating method. This application states that the change in oil content varies depending on the heating time and distance, and the final heating temperature, sample preparation method, or heating tool can be determined based on the change in oil content under various conditions.

[0053] In the above scheme, the first and second changes in oil content are determined by using aluminum foil obtained by both missing and non-missing coating methods, so as to determine the first and second heating methods. Then, the target heating method is comprehensively considered by referring to the heating methods under the two carbon coating methods, so that the determined target heating method is more accurate.

[0054] In some embodiments, the method of determining the target heating method based on the first heating method and the second heating method may be: in response to the first heating method and the second heating method being the same, taking the first heating method or the second heating method as the target heating method; or, in response to the first heating method and the second heating method being different, determining the weights of the first heating method and the second heating method, and performing weighted fusion of at least one heating parameter in the first heating method and the second heating method according to the weights to obtain the target heating method.

[0055] The first and second heating methods are the same. The manual states that under this heating method, aluminum foil sheets obtained by different carbonization methods can all achieve high oil carrying capacity, so this heating method can be directly used as the target heating method. If the two heating methods are different, they can be weighted and fused to obtain the target heating method. In some application scenarios, if one heating method has a weight of 0 and the other has a weight of 1, the heating method with a weight of 1 is directly used as the target heating method. In some application scenarios, if the weights of both heating methods are both intermediate values ​​between 0 and 1, at least some parameters of the two heating methods are multiplied by their respective weights and then added together to obtain the target heating method. Optionally, the weight values ​​can be dynamically set. For example, the weights can be set according to the ratio between the oil carrying capacity obtained by the first and second heating methods. For instance, if the only difference between the first and second heating methods is the heating time, and the first heating method involves heating for 1 hour with an oil carrying capacity of 30 mg / m³... 2 The second heating method involves heating for 1.5 hours with an oil content of 15 mg / m³. 2 If the weight of the first heating method is 30 / 45 and the weight of the second heating method is 15 / 45, then the final heating time is 1.17 hours. This is just an example; in other applications, if the difference in oil volume between the two heating methods is greater than or equal to a preset difference, the heating method with the larger oil volume will have its weight set to 1, meaning that heating method will be directly used as the target heating method. If at least two heating parameters differ between the first and second heating methods, the weights of these different heating parameters can be the same or different. The weights of each heating parameter can be preset or set according to the ratio of oil volume, etc.

[0056] In the above scheme, if the two heating methods are the same, one of them is directly determined as the target heating method. If the two heating methods are different, a more suitable target heating method can be determined by referring to the first heating method and the second heating method.

[0057] In some embodiments, the heating appliance has a first accommodating space for placing a plurality of aluminum foil sheets. The method of controlling the heating appliance to heat the plurality of aluminum foil sheets according to the target heating method may be: gradually heating the temperature of the first accommodating space in the heating appliance containing the plurality of aluminum foil sheets to the target temperature within a first preset time period; and continuously heating at the target temperature for a second preset time period, wherein the first preset time period is shorter than the second preset time period.

[0058] The first accommodating space can be a closable space. For example, after placing several sets of aluminum foil sheets in the first accommodating space, the space can be closed and reopened after heating is complete. Gradual heating to the target temperature can be achieved by heating at a uniform rate within a first preset time period or by heating to the target temperature in a non-linear manner. The several sets of aluminum foil sheets can be placed flat, rolled up, or separated by a heating bracket. Continuous heating at the target temperature for a second preset time period can be understood as maintaining the temperature in the heating appliance at the target temperature for the second preset time period.

[0059] In the above scheme, by setting a relatively short heating time and a relatively long holding time, the oil on the aluminum foil surface can be ensured to burn more completely, thereby making the amount of oil on the filter surface to be tested more accurate.

[0060] In some embodiments, the heating appliance includes a first accommodating space for holding a plurality of sets of aluminum foil sheets. The method for controlling the heating appliance to heat the plurality of sets of aluminum foil sheets according to a target heating method can be: placing different sets of aluminum foil sheets into different second accommodating spaces within a heating bracket. Each second accommodating space is independently configured within the heating bracket, and each set of aluminum foil sheets is obtained according to a specific acquisition time. The heating bracket is placed within the first accommodating space of the heating appliance to heat each set of aluminum foil sheets within the heating bracket.

[0061] For example, the aluminum foil sheets obtained from the aluminum foil to be tested can be grouped as a single group. Once the weight of one group reaches a preset weight, the next group of aluminum foil sheets is obtained. Alternatively, after all aluminum foil sheets have been obtained, they can be grouped according to the order in which they were obtained. The weight difference between different groups of aluminum foil sheets should be small; for example, in this embodiment, the weight of each group of aluminum foil sheets is selected to be between 30 and 40g. The function of the heating bracket is to separate the groups of aluminum foil sheets. If all groups of aluminum foil sheets are stacked together, the oil on the surface of the middle part of the aluminum foil sheets may not evaporate easily. By isolating the groups of aluminum foil sheets with the heating bracket, the oil on the surface of each group of aluminum foil sheets can evaporate more effectively.

[0062] In the above solution, by placing different groups of aluminum foil sheets in different compartments within the heating bracket, this solution ensures that the oil on the surface of the aluminum foil sheets can evaporate more fully compared to stacking the aluminum foil sheets together.

[0063] In some embodiments, the second receiving space includes a through slot formed by a plurality of sidewalls for placing groups of aluminum foil sheets.

[0064] The sidewalls can be perforated or non-perforated. In some applications, multiple through holes can be provided on the sidewalls, with each end of these through holes connecting to two receiving spaces. In other applications, no through holes are provided on the sidewalls. By setting through slots and placing each set of aluminum foil sheets in the corresponding through slots, the oil on the surface of the aluminum foil can be easily evaporated. The specific structure of the heating bracket can be seen in Figure 3. The heating bracket 10 can have two or more layers, and each layer can include multiple receiving spaces 100, and each receiving space includes a through slot 120 formed by multiple sidewalls 110. The size of the heating bracket 10 can be set according to the size of the heating appliance. Generally, the size of the heating bracket 10 will be smaller than the size of the internal receiving space of the heating appliance, so as to facilitate the placement of the heating bracket 10 inside the heating appliance.

[0065] In the above scheme, by setting the accommodating space as a through groove formed by several side walls, and placing each group of aluminum foil sheets in the corresponding through groove, the evaporation efficiency of the oil on the surface of each aluminum foil sheet can be improved compared to a closed or semi-closed accommodating space.

[0066] In some embodiments, the aluminum foil to be tested is an aluminum roll formed by winding, and the method further includes: obtaining multiple layers of target aluminum foil in the aluminum foil to be tested; obtaining multiple aluminum foil sheets from the central region of each layer of target aluminum foil; and grouping the aluminum foil sheets to obtain several groups of aluminum foil sheets.

[0067] Aluminum foil is typically produced in coils, allowing for the cutting of multiple layers of target aluminum foil and the extraction of several sheets from each layer. The central region can be understood as the area at a certain distance from the boundary of each target aluminum foil. In some applications, the distance between the central region and the target aluminum foil boundary may be less than the length or width of a single sheet, while in others, it may be greater than or equal to the length or width of a single sheet. Specifically, the cutting process can be understood as a sampling process; in other words, the boundary of each target aluminum foil is not sampled. The methods for obtaining target aluminum foil from the aluminum foil to be inspected and for obtaining individual sheets from the target aluminum foil can be either automated or manual, without specific limitations. For example, the automatic cutting system includes a cutting blade. The target aluminum foils are stacked, allowing the cutting blade to cut from the top layer to the bottom layer in one pass, resulting in a faster cutting speed. Alternatively, after cutting a single target aluminum foil, the automatic cutting system removes the cut foil from its cutting area and moves the next target aluminum foil to the cutting area so that the cutting blade can cut its center area. Manual cutting can also be performed by cutting one foil at a time, or by controlling the blade to extend directly into the overlapping area perpendicular to the direction of overlap to cut the overlapping target aluminum foils in one pass.

[0068] In the above scheme, multiple target aluminum foils are first obtained from the aluminum coil, and multiple aluminum foil sheets are obtained from the central area of ​​each target aluminum foil. Then, the obtained aluminum foil sheets are grouped to obtain several groups of aluminum foil sheets, which reduces the interference of the potentially contaminated area at the edge of each target aluminum foil on the detection of oil quantity, thereby ensuring the accuracy of the detection of oil quantity of the aluminum foil to be detected.

[0069] In some embodiments, the above-described method of grouping the aluminum foil sheets to obtain several sets of aluminum foil sheets includes: for each target aluminum foil layer, stacking multiple aluminum foil sheets obtained from the target aluminum foil to obtain at least one stack of aluminum foil sheets corresponding to the target aluminum foil; discarding the aluminum foil sheets in the top and bottom layers of the stack of aluminum foil sheets respectively; and combining the multiple stacks of aluminum foil sheets to obtain a set of aluminum foil sheets, thus obtaining several sets of aluminum foil sheets.

[0070] In some applications, after obtaining a single target aluminum foil from an aluminum coil, the obtained single target aluminum foil is rolled tightly to obtain multiple sub-coils. Alternatively, all the cut target aluminum foils can be rolled together to obtain a single sub-coil. In some applications, after cutting a single target aluminum foil, the cut single target aluminum foil is rolled tightly to obtain multiple sub-coils. After all the target aluminum foils are cut from the aluminum coil, one sub-coil is unfolded and cut to obtain a stack of aluminum foil sheets. Then, the next sub-coil is unfolded and cut to obtain a stack of aluminum foil sheets, and so on, until all the sub-coils have a stack of aluminum foil sheets. All aluminum foil sheets in a stack are cut from the same target aluminum foil. In some applications, all the cut target aluminum foils are rolled tightly to form a sub-coil. Subsequently, the sub-coil is flattened and cut sequentially to obtain several stacks of aluminum foil sheets. Each stack of aluminum foil sheets contains aluminum foil sheets cut from different aluminum foil sheets.

[0071] The oil on the surface of the bottom layer of aluminum foil in each stack may be rubbed off or adhere to other substances, affecting the initial weight. Similarly, the oil on the surface of the top layer may evaporate or adhere to other substances, also affecting the initial weight. Therefore, to ensure the accuracy of oil content detection, the top and bottom layers of aluminum foil in each stack are discarded. At least a portion of the stacks are then stacked to obtain a set of aluminum foil, thus yielding several sets. For example, the weight of each set of aluminum foil can be determined based on the maximum oil content when determining the relationship between oil content changes in the preparation method.

[0072] In the above scheme, after obtaining multiple stacks of aluminum foil, the top and bottom layers of aluminum foil that may be contaminated are discarded before being combined into several groups of aluminum foil, which can ensure the accuracy of the detection of the amount of oil in the aluminum foil to be tested.

[0073] In some embodiments, multiple cut aluminum foil sheets are stacked to obtain a stack of aluminum foil sheets; in response to the fact that all target aluminum foils have been cut, the aluminum foil sheets in the top and bottom layers of each group of aluminum foil sheets are discarded to obtain several groups of aluminum foil sheets.

[0074] In the above scheme, after cutting a stack of aluminum foil sheets, they are stacked and placed. After all the target aluminum foil sheets have been cut, the top and bottom layers of aluminum foil sheets in each stack that may be contaminated are discarded, which can ensure the accuracy of the detection of the oil content of the aluminum foil to be tested.

[0075] In some embodiments, the amount of oil carried by the aluminum foil to be tested is obtained based on the weight difference between the initial weight and the target weight, including: obtaining the ratio between the weight difference and the initial weight; determining a first product of the ratio and the thickness of a plurality of aluminum foil sheets; multiplying the first product by the density of the aluminum foil sheets to obtain a second product as the amount of oil carried by the plurality of aluminum foil sheets, and the amount of oil carried by the plurality of aluminum foil sheets as the amount of oil carried by the aluminum foil to be tested.

[0076] Optionally, each group of aluminum foil sheets has an initial weight and a target weight. That is, each group of aluminum foil sheets determines its oil content based on its initial weight, target weight, thickness, and density. The maximum oil content of each group of aluminum foil sheets can be used as the oil content of the aluminum foil to be tested. Alternatively, several groups of aluminum foil sheets can be weighed together to obtain an initial weight and a target weight, thus obtaining an oil content, which can be directly used as the oil content of the aluminum foil to be tested.

[0077] Specifically, the method for calculating the amount of oil on the aluminum foil can be found in formula (1):

[0078]

[0079] Where, m 前 Indicates the initial weight, m 后 h represents the target weight after heating. 厚度 This indicates the thickness of several sets of aluminum foil sheets, 2.7 g / m². 3 *1000 indicates the density of the aluminum foil.

[0080] In the above scheme, by considering the thickness and density of several aluminum foil sheets, the amount of oil on the surface of the aluminum foil sheet per unit weight can be determined.

[0081] In some applications, the aluminum foil to be tested is an aluminum roll. Multiple layers of target aluminum foil can be obtained first, and then each target aluminum foil can be cut to obtain several sets of aluminum foil sheets. Specifically, the method for obtaining multiple layers of target aluminum foil can be as follows: cut two narrow strips from the edge of the aluminum roll, tear the narrow strips of aluminum foil along their width to the other side of the aluminum roll, and remove the torn multiple layers of aluminum foil from the aluminum roll, approximately 20-30 layers, which yields 20-30 layers of target aluminum foil. The obtained multiple layers of target aluminum foil are then removed from the aluminum roll and tightly wound. In some embodiments, batch information can also be set for each target aluminum foil to facilitate subsequent recording of oil quantity detection results.

[0082] Then, perform the following steps on the tightly rolled aluminum foil to obtain several sets of aluminum foil sheets: 1. Lay the tightly rolled aluminum foil sample flat and make notches with a spacing of approximately 80mm in the width direction. 2. Tear off approximately 80mm*80mm aluminum foil. The tearing method can be manual tearing or cutting with a blade at the end of a robotic arm. 3. Repeat steps 1 and 2 to take multiple stacks of aluminum foil horizontally, taking samples in the order of 1-2-3-4-… as shown in Figure 4. 4. Remove the top and bottom layers of each stack and stack them together. The total weight of each set should be controlled between 30 and 40g. 5. Repeat steps 1 to 4, taking 3 or more sets from each roll of aluminum foil. For example, the method of cutting each layer of target aluminum foil can be referred to Figure 4. The central area of ​​the target aluminum foil is cut to obtain several aluminum foil pieces. The central area refers to the area that is a certain distance from the boundary of the target aluminum foil. For example, in Figure 4, the distance from the boundary can be 100mm in the width direction and 50mm in the length direction. Of course, this specific value of the distance from the boundary is only a distance. Other values ​​can be used in other embodiments. For example, the distance from the boundary can be 80-120mm in the width direction and 30-70mm in the length direction. The division of the central area is not specifically limited here.

[0083] After obtaining several sets of aluminum foil sheets, before weighing them, an auxiliary tool can be placed on a high-precision weighing disk to zero the electronic balance. Then, several sets of aluminum foil sheets are placed on the auxiliary tool. During weighing, the protective cover is closed to ensure weighing accuracy, and the weight m of the aluminum foil before baking is recorded. 前 , where m 前 Record the weight in grams and retain 4 decimal places.

[0084] After weighing, several sets of aluminum foil sheets were placed sequentially into the heating rack, with each compartment of the rack containing one set of aluminum foil sheets. The heating rack was then placed in a muffle furnace, which was set to heat from room temperature to 300°C (heating time ≤ 35 min), and baked for 1 hour at 300°C. After 1 hour of baking, the furnace temperature was allowed to cool to approximately 150°C. Using high-temperature gloves and sampling pliers, the heating rack was removed. The removed sets of aluminum foil sheets were cooled to room temperature before weighing. Specifically, the aluminum foil samples were removed from the heating rack using tweezers or similar tools. The electronic scale was zeroed before measurement, and the sets of aluminum foil sheets were placed into a tray. The protective cover was closed during weighing, and the weight (m) of the aluminum foil after baking was recorded. 后 The result is rounded to four decimal places. Then, the oil content of each group is obtained according to formula (1) above. The maximum oil content can be selected as the oil content of the aluminum foil to be tested. Among these, the results obtained from different carbonization methods include aluminum foil with carbonized powder shedding and oil content >12 mg / m³. 2 Normal aluminum foil ≤12mg / m 2 It fully meets the requirements for incoming aluminum foil inspection. At the same time, the dyne value method cannot distinguish between aluminum foil with carbon coating powdering and missing coating and normal aluminum foil.

[0085] Specific test results can be found in the tool R&R (nested) reports for oil content measurement shown in Figures 5 to 9. Figure 5 shows the component variation diagram, indicating that the variation caused by different tools is small, while the variation between components is large. Figure 6 is the oil content multiplied by sample number (experimenter). The sample number is the number of the aluminum foil being tested. As shown in Figure 6, the results obtained by different operators measuring the oil content of different aluminum foils have small differences. Specifically, the horizontal axis 1 to 10 represent the experimental results of experimenter 1 for sample numbers 1 to 10, the horizontal axis 11 to 20 represent the experimental results of experimenter 2 for sample numbers 1 to 10, and the horizontal axis 21 to 30 represent the experimental results of experimenter 3 for sample numbers 1 to 10. Figure 7 is the R control chart (by experimenter), where UCL = 2.911. LCL = 0, Figure 8 is the Xbar control chart (by experimenter), where UCL = 8.92. LCL = 6.61. Figure 9 shows the oil content * experimenter figure. Figure 10 shows the results of oil content testing for aluminum foil with carbon coating powder shedding and normal aluminum foil produced by manufacturers A to E. It is obvious that the oil content of aluminum foil with carbon coating powder shedding is significantly higher than that of normal aluminum foil.

[0086] When testing the oil content detection method of aluminum foil provided in this embodiment, it is tested using different testing methods, such as different operators performing the method and testing the oil content of aluminum foil produced by different manufacturers, in order to test the repeatability and reproducibility of the oil content detection method of aluminum foil and determine that the oil content detection method of aluminum foil provided in this embodiment has repeatability and reproducibility.

Claims

1. A method for detecting the oil content of aluminum foil, characterized in that, include: Obtain the initial weight of several sets of aluminum foil sheets, which are cut from the aluminum foil to be tested; The target heating method for the several groups of aluminum foil sheets is determined based on the oil content variation relationship, and the heating equipment is controlled to heat the several groups of aluminum foil sheets according to the target heating method. The oil content variation relationship includes the oil content of aluminum foil sheets obtained by at least one carbonization method under multiple heating methods. Obtain the target weight of the several groups of aluminum foil sheets after heating; The amount of oil on the aluminum foil to be tested is obtained based on the weight difference between the initial weight and the target weight.

2. The method according to claim 1, characterized in that, The method for detecting the oil content of the aluminum foil also includes: The amount of oil carried by aluminum foil sheets obtained by different carbon coating methods under various heating methods is obtained. The heating methods include at least one or more of the following heating parameters: heating time, time required for heating up, heating temperature, cooling time, and the placement method of the several groups of aluminum foil sheets in the heating appliance. At least one heating parameter is different in different heating methods. Based on the amount of oil carried by the aluminum foil obtained by each of the aforementioned carbon coating methods under various heating methods, the relationship between the changes in the amount of oil carried is obtained.

3. The method according to claim 2, characterized in that, The coating method includes both incomplete and complete coating. The oil content variation relationship includes the first oil content variation of the aluminum foil obtained by incomplete coating under various heating methods and the second oil content variation of the aluminum foil obtained by complete coating under various heating methods. The determination of the target heating method for the several groups of aluminum foils based on the oil content variation relationship includes: Determine the first heating method corresponding to the maximum oil volume in the first oil volume change, and determine the second heating method corresponding to the maximum oil volume in the second oil volume change; The target heating method is determined based on the first heating method and the second heating method.

4. The method according to claim 3, characterized in that, Determining the target heating method based on the first heating method and the second heating method includes: In response to the fact that the first heating method and the second heating method are the same, the first heating method or the second heating method is taken as the target heating method; Alternatively, in response to the difference between the first heating method and the second heating method, the weights of the first heating method and the second heating method are determined, and at least one heating parameter of the first heating method and the second heating method is weighted and fused according to the weights to obtain the target heating method.

5. The method according to claim 4, characterized in that, The method further includes: The weights of the first heating method and the second heating method are determined based on the ratio between the oil content obtained by the first heating method and the oil content obtained by the second heating method; or, In response to a difference between the oil content obtained by the first heating method and the second heating method being greater than or equal to a preset difference, the weight of the heating method corresponding to the one with the larger oil content is set to 1, wherein the heating method with a weight of 1 is selected as the target heating method; or, In response to the existence of at least two different heating parameters in the first heating method and the second heating method, the weight of each heating parameter is determined respectively. The weight of each heating parameter can be preset or determined according to the ratio between the oil content obtained by the first heating method and the second heating method.

6. The method according to any one of claims 1 to 5, characterized in that, The heating appliance has a first accommodating space for placing the plurality of aluminum foil sheets. The control heating appliance heats the plurality of aluminum foil sheets according to the target heating method, including: The temperature of the first accommodating space in the heater containing the plurality of aluminum foil sheets is gradually heated to the target temperature within a first preset time period; The target temperature is continuously heated for a second preset time period, where the first preset time period is shorter than the second preset time period.

7. The method according to any one of claims 1 to 6, characterized in that, The heating appliance has a first receiving space for placing the plurality of aluminum foil sheets. The control heating appliance heats the plurality of aluminum foil sheets according to the target heating method, including: The aluminum foil sheets of different groups are placed in different second receiving spaces in the heating bracket, and each second receiving space is set independently in the heating bracket. The aluminum foil sheets of different groups are divided according to the acquisition time. The heating bracket is placed within the first accommodating space of the heating appliance to heat each group of aluminum foil sheets in the heating bracket.

8. The method according to claim 7, characterized in that, The second receiving space includes a through slot formed by a plurality of sidewalls for placing the groups of aluminum foil sheets.

9. The method according to any one of claims 1 to 8, characterized in that, The aluminum foil to be tested is an aluminum coil formed by winding, and the method further includes: Obtain the multilayer target aluminum foil in the aluminum foil to be tested; Multiple aluminum foil sheets are obtained from the central region of each layer of the target aluminum foil; The aluminum foil sheets are grouped to obtain the several groups of aluminum foil sheets.

10. The method according to claim 9, characterized in that, The process of grouping the aluminum foil sheets to obtain the plurality of groups of aluminum foil sheets includes: For each layer of the target aluminum foil, multiple aluminum foil sheets obtained from the target aluminum foil are stacked to obtain at least one stack of aluminum foil sheets corresponding to the target aluminum foil. Discard the aluminum foil sheets that are stacked on the top and bottom layers of the multi-layer aluminum foil sheets respectively; Multiple stacks of aluminum foil are combined to obtain a set of aluminum foil, thus obtaining the aforementioned sets of aluminum foil.

11. The method according to claim 9, characterized in that, The method further includes: Based on the oil content variation relationship, the method for obtaining the several sets of aluminum foil sheets from the aluminum foil to be tested is determined.

12. The method according to any one of claims 1 to 11, characterized in that, The process of determining the oil content of the aluminum foil to be tested based on the weight difference between the initial weight and the target weight includes: Obtain the ratio between the weight difference and the initial weight; Determine the first product of the ratio and the thickness of the plurality of groups of aluminum foil sheets; The second product obtained by multiplying the first product by the density of the aluminum foil is used as the oil content of the plurality of aluminum foils, and the oil content of the plurality of aluminum foils is used as the oil content of the aluminum foil to be tested.

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