A processing method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film

Abstract

The invention discloses a processing method for improving the residual amount of R-angle aluminum foil after deep punching of aluminum-plastic film, comprising the following steps: 1) preparing aluminum foil under the condition that the ingot temperature is 440-525°C, rolling, and ensuring that the outlet temperature reaches 500-560°C; 2) compounding nylon film and aluminum foil to obtain aluminum-plastic film. The invention limits the ingot temperature and outlet temperature of the aluminum foil. When the aluminum foil is rolled under this condition, the grain size of the aluminum foil is controlled. When the outlet temperature increases, the speed of aluminum foil recrystallization increases at the same extrusion speed, and the aluminum foil grain size of the aluminum foil becomes larger. The higher the grain size level of the aluminum foil, the finer the grain size of the aluminum foil surface. When the aluminum-plastic film undergoes plastic deformation during deep punching, the tensile force is dispersed into more grains, and the grain boundary prevents the expansion of cracks, thereby improving the mechanical properties of the aluminum foil and strengthening the tensile resistance, thereby increasing the residual amount of R-angle aluminum foil when the aluminum-plastic film is used.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum-plastic films for lithium battery packaging, and in particular to a processing method for increasing the residual amount of R-corner aluminum foil after deep punching of the aluminum-plastic film. Background Art

[0002] The green, high-energy and environmentally friendly lithium-ion batteries that appeared in the 1990s have become one of the most popular automotive power sources due to their high energy density, long cycle life, and high operating voltage. Packaging is an indispensable and important part of lithium batteries. Lithium batteries cannot exist independently without packaging. The service life of the packaging is the same as the service life of the lithium battery. The life cycle of the product is actually the process of the packaging gradually becoming ineffective. At present, the outer packaging of batteries can be divided into four types: plastic shell, steel shell, aluminum shell and aluminum-plastic film. Aluminum-plastic film materials have become one of the main packaging materials for lithium batteries due to their advantages such as light weight and good formability.

[0003] At present, in the aluminum-plastic film industry, the most concerned thing about the aluminum-plastic film after deep punching is the depth of the product, and less attention is paid to the residual amount of R-corner aluminum foil after deep punching. However, when making power batteries, major customers pay special attention to the residual amount of R-corner aluminum foil after deep punching. This is because in the production of power batteries, the amount of R-corner aluminum foil residue determines the safety and service life of the battery. Therefore, customers require that the residual amount of R-corner aluminum foil after deep punching be kept above 60%. A value lower than this will cause major safety hazards to the use of the battery. At present, most products of aluminum-plastic film manufacturers in the same industry are maintained at around 50%, which not only affects the deep punching performance, but also poses a hidden danger to battery protection. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a processing method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film, by limiting the production process of aluminum foil, to change the grain size of the aluminum foil material, so as to improve the tensile strength and plastic strength of the aluminum material, thereby increasing the residual amount of R-corner aluminum foil when the aluminum-plastic film is used.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film comprises the following steps:

[0007] 1) Under the condition that the ingot temperature is 440-525° C., the aluminum foil is prepared by rolling to ensure that the outlet temperature reaches 500-560° C.;

[0008] 2) Compounding nylon film with aluminum foil to obtain aluminum-plastic film.

[0009] Furthermore, in step 1), the steel sheet is rolled using an extrusion drum at 400-450° C., and the rolling speed is 800-1000 m / min.

[0010] Furthermore, in step 2), before the nylon film and the aluminum foil are compounded, the surface of the nylon film is subjected to a corona treatment with a corona intensity of 0.5 to 2 kW.

[0011] Furthermore, in step 2), before the nylon film and the aluminum foil are compounded, the surface of the nylon film is humidified, and the humidity is controlled to be 65-75%.

[0012] Furthermore, in step 2), the nylon film and the aluminum foil are bonded by an adhesive.

[0013] Furthermore, in step 2), the nylon film and the aluminum foil are bonded by an adhesive and then aged at 45 to 55° C. for 72 to 120 hours.

[0014] Furthermore, in step 2), the thickness of the aluminum foil is 20 to 100 μm.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The present invention limits the ingot temperature and outlet temperature of the aluminum foil. When the aluminum foil is rolled under these conditions, the grain size of the aluminum foil is controlled. When the outlet temperature increases, at the same extrusion speed, the rate of recrystallization of the aluminum foil increases, and the grain size of the aluminum foil becomes larger. The higher the grain size level of the aluminum foil, the finer the grain size on the surface of the aluminum foil. When the aluminum-plastic film undergoes plastic deformation during deep punching, the tensile force is dispersed into more grains, and the grain boundaries prevent the expansion of cracks, thereby improving the mechanical properties of the aluminum foil and strengthening its tensile resistance, thereby increasing the amount of R-angle aluminum foil residue when the aluminum-plastic film is used.

[0017] (2) The present invention can also control the grain size of the aluminum foil by controlling the extrusion (rolling) speed. The faster the extrusion speed, the higher the grain size of the aluminum foil. Therefore, the ingot temperature, outlet temperature and extrusion speed of the aluminum foil will affect the grain size of the aluminum foil.

[0018] (3) The present invention can change the physical properties of nylon itself through the physical means of corona humidification, change the area of ​​contact between the surface of the nylon layer and the surrounding air, and use the strong water absorption of nylon to make nylon absorb moisture in the air, thereby changing the softness of nylon. Without destroying the impact strength of nylon, the tensile strength of nylon is increased. Combined with aluminum foil, the deep-drawing deformation ability of the composite aluminum-plastic film is increased, thereby meeting the customer's adaptability to high-drawing products. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a schematic diagram of the aluminum foil surface grain size of level 8 in Example 1;

[0020] Figure 2 This is a schematic diagram of the aluminum foil surface grain size level 4 of Comparative Example 6. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0022] Example 1

[0023] A method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film comprises the following steps:

[0024] 1) When the ingot temperature is 440° C., the aluminum foil is rolled through an extrusion drum at 400° C. at a rolling speed of 1000 m / min, and the outlet temperature is ensured to reach 500° C., and then aged at 45° C. for 120 h to obtain the aluminum foil;

[0025] 2) Bond the nylon film and aluminum foil with an adhesive to obtain an aluminum-plastic film.

[0026] Before the nylon film is compounded with the aluminum foil, the surface of the nylon film is subjected to corona humidification treatment, the corona intensity is 0.5 kW, and the humidification control humidity is 65%.

[0027] Example 2

[0028] A method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film comprises the following steps:

[0029] 1) When the ingot temperature is 440° C., the ingot is rolled at 400° C. through an extrusion cylinder at a rolling speed of 800 m / min, and the outlet temperature is ensured to reach 500° C., and then the ingot is aged at 45° C. for 120 h to prepare an aluminum foil;

[0030] 2) Bond the nylon film and aluminum foil with an adhesive to obtain an aluminum-plastic film.

[0031] Before the nylon film is compounded with the aluminum foil, the surface of the nylon film is subjected to corona humidification treatment, the corona intensity is 0.5 kW, and the humidification control humidity is 65%.

[0032] Example 3

[0033] A method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film comprises the following steps:

[0034] 1) When the ingot temperature is 525° C., the aluminum foil is prepared by rolling the aluminum foil through an extruder at 450° C. and a rolling speed of 900 m / min, and aging the aluminum foil at 55° C. for 120 h under the condition that the outlet temperature reaches 560° C.;

[0035] 2) Bond the nylon film and aluminum foil with an adhesive to obtain an aluminum-plastic film.

[0036] Before the nylon film is compounded with the aluminum foil, the surface of the nylon film is subjected to corona humidification treatment, the corona intensity is 0.5-2kW, and the humidification humidity is controlled to be 65-75%.

[0037] Example 4

[0038] A method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film, comprising the following steps:

[0039] 1) When the ingot temperature is 500° C., the aluminum foil is prepared by rolling the aluminum foil through an extrusion cylinder at 420° C. and a rolling speed of 1000 m / min, and aging the aluminum foil at 50° C. for 100 h under the condition that the outlet temperature reaches 550° C.;

[0040] 2) Bond the nylon film and aluminum foil with an adhesive to obtain an aluminum-plastic film.

[0041] Before the nylon film is compounded with the aluminum foil, the surface of the nylon film is subjected to corona humidification treatment, the corona intensity is 1 kW, and the humidification control humidity is 70%.

[0042] Example 5

[0043] A method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film, comprising the following steps:

[0044] 1) When the ingot temperature is 520° C., the aluminum foil is prepared by rolling the aluminum foil through an extrusion cylinder at 440° C. and a rolling speed of 1000 m / min, and aging the aluminum foil at 50° C. for 80 h under the condition that the outlet temperature reaches 520° C.;

[0045] 2) Bonding the nylon film and the aluminum foil with an adhesive to obtain an aluminum-plastic film.

[0046] Before the nylon film is compounded with the aluminum foil, the surface of the nylon film is subjected to corona humidification treatment, the corona intensity is 1 kW, and the humidification control humidity is 65%.

[0047] Comparative Example 1

[0048] The difference between Comparative Example 1 and Example 1 is that the ingot temperature of Comparative Example 1 is 400°C, the rolling temperature is 400°C, the outlet temperature is 450°C, and the other conditions are the same as those of Example 1.

[0049] Comparative Example 2

[0050] The difference between Comparative Example 2 and Example 1 is that the ingot temperature of Comparative Example 1 is 530°C, the rolling temperature is 480°C, the outlet temperature is 570°C, and the other conditions are the same as those of Example 1.

[0051] Comparative Example 3

[0052] The difference between Comparative Example 3 and Example 1 is that the ingot temperature of Comparative Example 1 is 570°C, the rolling temperature is 570°C, the outlet temperature is 570°C, and the other conditions are the same as those of Example 1.

[0053] Comparative Example 3

[0054] The difference between Comparative Example 3 and Example 1 is that the ingot temperature of Comparative Example 1 is 570°C, the rolling temperature is 570°C, the outlet temperature is 570°C, and the other conditions are the same as those of Example 1.

[0055] Comparative Example 4

[0056] The difference between Comparative Example 4 and Example 1 is that the ingot temperature of Comparative Example 4 is 570°C, the rolling temperature is 570°C, the outlet temperature is 570°C, and the other conditions are the same as those of Example 1.

[0057] Comparative Example 5

[0058] The difference between Comparative Example 4 and Example 1 is that the ingot temperature of Comparative Example 4 is 420°C, the rolling temperature is 390°C, the outlet temperature is 490°C, and the other conditions are the same as those of Example 1.

[0059] Comparative Examples 6 to 9

[0060] The difference between Comparative Examples 6 to 9 and Example 1 is that the extrusion speeds of Comparative Examples 6 to 9 are 500 m / min, 600 m / min and 700 m / min, respectively.

[0061] Performance Testing

[0062] 1. The thickness of the aluminum foil used in Examples 1 to 5 and Comparative Examples 1 to 5 is 40 μm. The tensile strength and the residual R-angle of the aluminum foil treated by Examples 1 to 5 and Comparative Examples 1 to 5 are tested, and the residual rate of the R-angle aluminum foil is calculated, as shown in Table 1.

[0063] Table 1 Tensile strength and aluminum foil R angle residual data of each group

[0064]

[0065] It can be seen from Table 1 that the tensile strength of the aluminum foil treated in Examples 1 to 5 is significantly improved, and the residual amount of the R-corner aluminum foil after deep punching is maintained at more than 60%, thereby improving the safety and service life of the battery.

[0066] 2. Effect of extrusion (rolling) speed on grain size of aluminum foil

[0067] The grain sizes of the aluminum foils of Examples 1 to 2 and Comparative Examples 6 to 9 were detected, as shown in Table 2.

[0068] Table 2 Grain size data of aluminum foil of Example 1 and Comparative Examples 6 to 9

[0069]

[0070]

[0071] From Table 2 and Figures 1-2 It can be seen that when the extrusion speed is 1000m / min, the grain size of the aluminum foil is as high as 8 levels, while the grain size of Comparative Example 6 is only 4 levels. It can be seen that within the extrusion speed range of 500-1000m / min, the higher the extrusion speed, the higher the grain size. The grain size on the surface of the aluminum foil is fine, and when the aluminum-plastic film undergoes plastic deformation during deep punching, the tensile force is dispersed into more grains, and the grain boundaries will prevent the expansion of cracks, thereby improving the mechanical properties of the aluminum foil and strengthening its tensile resistance.

[0072] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film, characterized in that: The following steps are involved: 1) When the ingot temperature is 440-525° C., the aluminum foil is prepared by rolling the ingot at 400-450° C. through an extrusion cylinder, wherein the rolling temperature is lower than the ingot temperature, the rolling speed is 800-1000 m / min, and the outlet temperature is ensured to reach 500-560° C.; 2) Compounding nylon film with aluminum foil to obtain aluminum-plastic film.

2. The method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film according to claim 1, characterized in that: In step 2), before the nylon film is compounded with the aluminum foil, the surface of the nylon film is subjected to a corona treatment with a corona intensity of 0.5 to 2 kW.

3. The method for increasing the residual amount of R-corner aluminum foil after deep punching of aluminum-plastic film according to claim 1, characterized in that: In step 2), before the nylon film and the aluminum foil are compounded, the surface of the nylon film is humidified, and the humidity is controlled to be 65-75%.

4. The method for increasing the residual amount of R-corner aluminum foil after deep-drawing of aluminum-plastic film according to claim 1, characterized in that: In step 2), the nylon film and the aluminum foil are bonded by an adhesive.

5. The method for increasing the residual amount of R-corner aluminum foil after deep-drawing of aluminum-plastic film according to claim 4, characterized in that: In step 2), the nylon film and the aluminum foil are bonded by an adhesive and then aged at 45 to 55° C. for 72 to 120 hours.

6. The method for increasing the residual amount of R-corner aluminum foil after deep-drawing of aluminum-plastic film according to claim 1, characterized in that: In step 2), the thickness of the aluminum foil is 20 to 100 μm.

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