Aluminum plastic film and preparation method thereof, battery, battery pack and electric equipment

Abstract

The invention provides an aluminum-plastic film and a preparation method thereof, a battery, a battery pack and electric equipment. The aluminum-plastic film comprises a nylon layer, a first passivation layer, a composite metal layer, a second passivation layer and a polypropylene layer which are sequentially stacked, the composite metal layer comprises an aluminum layer, a copper layer and a nickel layer which are sequentially stacked. The aluminum-plastic film has better electrochemical corrosion resistance, and the safety of the battery can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of battery energy, and relates to an aluminum-plastic film, in particular to an aluminum-plastic film and a preparation method thereof, a battery, a battery pack and an electrical device. Background Art

[0002] At present, aluminum-plastic film is widely used in consumer batteries such as mobile phones, tablets, and Bluetooth headsets due to its good processability, formability, and barrier properties. Especially with the gradual rise of new energy vehicles, the use of aluminum-plastic film has also ushered in explosive growth.

[0003] Typically, power batteries used in new energy vehicles have high safety requirements, especially long-term reliability. However, as the battery's operating time increases, the aluminum-plastic film is prone to corrosion and leakage, causing battery failure and posing a safety hazard. This is primarily due to the plastic film packaging process being affected by factors such as the packaging machine, packaging temperature, packaging time, and packaging pressure. The PP layer at the seal edge or fold is prone to damage. When the negative electrode metal strip and the aluminum in the aluminum-plastic film overlap, ion and electron channels are formed. This causes lithium ions to embed into the aluminum layer of the aluminum-plastic film during charging and discharging, forming a lithium-aluminum alloy. This corrodes the aluminum-plastic film and ultimately causes battery leakage and failure.

[0004] Therefore, it is necessary to develop a new aluminum-plastic film to effectively improve the electrochemical corrosion resistance of the aluminum-plastic film. Summary of the Invention

[0005] In view of the above-mentioned defects, the present invention provides an aluminum-plastic film, which has good electrochemical corrosion resistance and can effectively improve the safety of the battery.

[0006] The present invention also provides a method for preparing the aluminum-plastic film. The aluminum-plastic film prepared by the preparation method has good electrochemical corrosion resistance and can effectively improve the safety of the battery.

[0007] The present invention also provides a battery, comprising the aluminum-plastic film or the aluminum-plastic film prepared by the above preparation method, so the battery has high safety.

[0008] The present invention also provides a battery pack, comprising the aluminum-plastic film, or the aluminum-plastic film prepared by the above-mentioned preparation method, or the above-mentioned battery, so that the battery pack has high safety.

[0009] The present invention also provides an electrical device comprising the aluminum-plastic film, or the aluminum-plastic film prepared by the preparation method, or the battery. Therefore, the electrical device has a long service life and high safety.

[0010] The first aspect of the present invention provides an aluminum-plastic film, which includes a nylon layer, a first passivation layer, a composite metal layer, a second passivation layer, and a polypropylene layer stacked in sequence; the composite metal layer includes an aluminum layer, a copper layer, and a nickel layer stacked in sequence.

[0011] The aluminum-plastic film as described above, wherein the thickness of the composite metal layer is 30μm to 70μm; preferably, the thickness of the aluminum layer is 27μm to 65μm; and / or the thickness of the copper layer is 2μm to 3μm; and / or the thickness of the nickel layer is 0.5μm to 1μm.

[0012] The aluminum-plastic film as described above, wherein the nickel layer includes phosphorus and / or tungsten; and the nickel layer satisfies:

[0013] 6%≤A / C≤8%, and / or, 0.1%≤B / C≤1%,

[0014] Wherein, A is the mass content of phosphorus in the nickel layer, B is the mass content of tungsten in the nickel layer, and C is the mass content of nickel in the nickel layer, and the units of A, B, and C are the same.

[0015] The aluminum-plastic film as described above, wherein the first passivation layer includes chromium element, and the content of the chromium element in the first passivation layer is 4 mg / m 2 ~6 mg / m 2 and / or, the second passivation layer includes chromium, the chromium content in the second passivation layer is 15mg / m 2 ~20 mg / m 2 .

[0016] The aluminum-plastic film as described above, wherein the nylon layer comprises a nylon-based material, and the nylon-based material comprises polycaprolactam and / or polyhexamethylene adipamide; preferably, the thickness of the nylon layer is 10 μm to 25 μm.

[0017] The aluminum-plastic film as described above, wherein the polypropylene layer comprises an adhesive layer and a polypropylene sublayer stacked in sequence, the adhesive layer is arranged close to the second passivation layer; the adhesive layer comprises maleic anhydride modified polypropylene material, and the polypropylene sublayer comprises a polypropylene material.

[0018] The aluminum-plastic film as described above, wherein the grafting rate of maleic anhydride in the maleic anhydride-modified polypropylene material is 0.5% to 3.5%.

[0019] The aluminum-plastic film as described above, wherein the polypropylene sublayer includes a first polypropylene sublayer and a second polypropylene sublayer stacked in sequence, and the first polypropylene sublayer is arranged close to the adhesive layer; preferably, the melting point of the first polypropylene sublayer is 160°C to 170°C, and the melt index is 2g / 10min to 5g / 10min, and the melting point of the second polypropylene sublayer is 135°C to 145°C, and the melt index is 5g / 10min to 10g / 10min.

[0020] The aluminum-plastic film as described above, wherein the thickness ratio of the adhesive layer, the first polypropylene sublayer and the second polypropylene sublayer is (0.7-1.5):(6-8):(0.5-1.5); preferably, the thickness of the polypropylene layer is 60 μm-80 μm.

[0021] The aluminum-plastic film as described above, wherein the aluminum-plastic film further comprises a polyethylene terephthalate layer, and the polyethylene terephthalate layer is arranged on a side of the nylon layer away from the first passivation layer.

[0022] In the aluminum-plastic film as described above, the polyethylene terephthalate layer has a thickness of 1.5 μm to 4.5 μm.

[0023] The aluminum-plastic film as described above, wherein the aluminum-plastic film further includes a sealing layer, which is arranged between the composite metal layer and the second passivation layer; the sealing layer includes a silane coupling agent; preferably, the silane coupling agent includes at least one of polyacrylic resin, aminosilane coupling agent, vinyl silane coupling agent, and epoxy silane coupling agent.

[0024] A second aspect of the present invention provides a method for preparing the aluminum-plastic film of the first aspect, comprising the following steps:

[0025] Compounding copper and aluminum to obtain a copper-aluminum composite layer; then performing nickel plating on the surface of the copper layer in the copper-aluminum composite layer to obtain a composite metal layer;

[0026] A first passivation layer and a nylon layer are sequentially stacked on the aluminum layer side of the composite metal layer, and a second passivation layer and a polypropylene layer are sequentially stacked on the nickel layer side of the composite metal layer to obtain the aluminum-plastic film.

[0027] In the above-mentioned preparation method, the method of compounding the copper material and the aluminum material includes a cold rolling process, and the cold rolling process includes:

[0028] Copper and aluminum materials are used as raw materials, and the raw materials are pretreated to remove surface oxides and impurities; the pretreated raw materials are sent to a cold rolling unit, and undergo multiple continuous cold rolling processes to gradually reduce the thickness. After reaching the designed thickness, annealing is performed to obtain the copper-aluminum composite layer.

[0029] In the preparation method as described above, after the first cold rolling, the deformation of the raw material is not less than 65%.

[0030] In the preparation method as described above, the annealing treatment is performed at a temperature of 300° C. to 500° C. and for a time of 2 h to 8 h.

[0031] In the preparation method as described above, a polyethylene terephthalate layer is provided on the side of the nylon layer away from the first passivation layer.

[0032] A third aspect of the present invention provides a battery, comprising the aluminum-plastic film described in the first aspect, or the aluminum-plastic film prepared by the preparation method described in the second aspect.

[0033] A fourth aspect of the present invention provides a battery pack, comprising the aluminum-plastic film according to the first aspect, or the aluminum-plastic film prepared by the preparation method according to the second aspect, or the battery according to the first aspect.

[0034] A fifth aspect of the present invention provides an electrical device, comprising the aluminum-plastic film described in the first aspect, or the aluminum-plastic film prepared by the preparation method described in the second aspect, or the battery described in the third aspect, or the battery pack described in the fourth aspect.

[0035] The aluminum-plastic film of the present invention comprises a nylon layer, a first passivation layer, a composite metal layer, a second passivation layer, and a polypropylene layer stacked in sequence. The composite metal layer comprises an aluminum layer, a copper layer, and a nickel layer. The copper layer effectively reduces the surface potential of the aluminum layer, inhibiting electrochemical corrosion during leakage and preventing leakage corrosion in the battery. The nickel layer facilitates the formation of the passivation layer, which effectively inhibits side reactions between the electrolyte and the aluminum layer. Therefore, the aluminum-plastic film of the present invention can achieve high electrochemical corrosion resistance while meeting application requirements, significantly improving battery safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment;

[0037] Figure 2 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment;

[0038] Figure 3 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment;

[0039] Figure 4 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment;

[0040] Figure 5 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment;

[0041] Figure 6 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment.

[0042] Description of reference numerals:

[0043] 1- nylon layer; 2- first passivation layer; 3- composite metal layer; 31- aluminum layer; 32- copper layer; 33- nickel layer; 4- second passivation layer; 5- polypropylene layer; 51- adhesive layer; 52- polypropylene sublayer; 521- first polypropylene sublayer; 522- second polypropylene sublayer; 6- polyethylene terephthalate layer; 7- sealing layer. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0045] For soft-pack batteries, the sealing quality directly determines the performance of the battery. Currently, commonly used battery packaging materials include coated paper, composite polyester film, and aluminum-plastic film. Coated paper, which is a paper with a coating formed on its surface, offers advantages such as low cost, environmental friendliness, excellent tear resistance, and airtightness. However, compared to other packaging materials, its performance is inferior and it is generally only suitable for packaging low-performance soft-pack batteries. Composite polyester film offers advantages such as high mechanical strength, good transparency, and excellent high and low temperature resistance, but its production process is complex and costly, making it generally suitable for packaging high-end soft-pack batteries. Compared to other packaging materials, aluminum-plastic film offers superior barrier properties, heat sealing performance, resistance to electrolyte and strong acid corrosion, and excellent ductility, flexibility, and mechanical strength, making it suitable for packaging products of various shapes. Therefore, compared to other packaging materials, aluminum-plastic film is more suitable for battery packaging.

[0046] However, as the battery's operating time increases, the aluminum-plastic film is prone to corrosion and leakage. This is mainly because the plastic film packaging process is affected by the packaging machine, packaging temperature, packaging time, packaging pressure, etc. The PP layer at the seal edge or folded edge is prone to damage, and leakage will occur at the damaged location, forming an ion channel between the aluminum layer and the anode (i.e., the negative electrode of the battery cell); and when the tab packaging location is damaged, the negative tab metal strip will overlap with the aluminum in the aluminum-plastic film to form an electron channel. During the charge and discharge process, lithium ions will be embedded in the aluminum layer of the aluminum-plastic film, forming a lithium-aluminum alloy, causing the aluminum layer to be continuously corroded and pulverized, causing more severe damage, and ultimately leading to battery leakage and failure.

[0047] After research, the inventors found that the main reason for electrochemical corrosion is that the potential of the aluminum layer is lower than that of the negative electrode of the battery cell. Therefore, if you want to block the electrochemical reaction between the aluminum layer and the negative electrode during the charging and discharging process of the battery when leakage occurs, increasing the potential of the aluminum layer is an effective way.

[0048] Therefore, the inventors have achieved this by adding a layer of copper to the surface of the aluminum layer (the surface facing the battery cell) (hereinafter referred to as the copper-aluminum composite layer). This effectively improves the surface potential of the aluminum layer and prevents electrochemical corrosion of the aluminum-plastic film. To prevent reactions between the aluminum layer and the electrolyte and to improve the bonding strength between the aluminum layer and the glue or adhesive, a passivation layer is often required on both sides of the copper-aluminum composite layer. However, because the copper layer in the copper-aluminum composite layer is not very active and cannot be passivated, a nickel layer is also required on the surface of the copper layer (the surface facing away from the aluminum layer) to ensure the formation of the passivation layer.

[0049] Based on the above analysis, the first aspect of the present invention provides an aluminum-plastic film, which includes a nylon layer, a first passivation layer, a composite metal layer, a second passivation layer, and a polypropylene layer stacked in sequence; the composite metal layer includes an aluminum layer, a copper layer, and a nickel layer stacked in sequence.

[0050] The aluminum-plastic film of the present invention comprises a nylon layer, a first passivation layer, a composite metal layer, a second passivation layer, and a polypropylene layer stacked in sequence. The composite metal layer comprises an aluminum layer, a copper layer, and a nickel layer stacked in sequence. The copper layer effectively reduces the surface potential of the aluminum layer, blocking the electrochemical reaction between the aluminum layer and the negative electrode during battery charging and discharging, thereby inhibiting electrochemical corrosion during leakage and preventing further damage that could lead to battery failure. The nickel layer ensures the subsequent formation of the passivation layer. By providing the first and second passivation layers on either side of the composite metal layer, the composite metal layer is effectively protected from corrosion by external water and oxygen or the electrolyte within the battery, inhibiting reactions between the electrolyte and the aluminum layer. The nylon layer further enhances the deep-draw performance of the aluminum-plastic film and also provides safety protection. The polypropylene layer provides heat sealing and electrolyte corrosion protection, ensuring heat-sealing conditions for securing the lithium-ion battery package and preventing electrolyte leakage and corrosion of the aluminum foil during packaging.

[0051] Therefore, the aluminum-plastic film of the present invention has high electrochemical corrosion resistance while meeting application requirements.

[0052] Figure 1 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment, Figure 1In the Z direction, the aluminum-plastic film includes a nylon layer 1, a first passivation layer 2, a composite metal layer 3, a second passivation layer 4, and a polypropylene layer 5 stacked in sequence; wherein the composite metal layer 3 includes an aluminum layer 31, a copper layer 32, and a nickel layer 33 stacked in sequence.

[0053] Furthermore, the thickness of the composite metal layer 3 , as well as the thicknesses of the aluminum layer 31 , the copper layer 32 and the nickel layer 33 therein, can also be controlled.

[0054] In one embodiment, the thickness of the composite metal layer 3 is 30 μm to 70 μm. Within this range, the thickness of the composite metal layer 3 is moderate, which can achieve a high punching depth and reduce costs. The punching depth refers to the maximum depth that the aluminum-plastic film can reach during the stamping process.

[0055] Illustratively, the thickness of the composite metal layer 3 may be 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm or 70 μm, or a range consisting of any two of these values.

[0056] In a specific embodiment, the thickness of the aluminum layer 31 is 27 μm to 65 μm. Within this range, the thickness of the aluminum layer 31 is moderate, which can achieve a higher punching depth and reduce costs.

[0057] Illustratively, the thickness of the aluminum layer 31 may be 27 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm or 65 μm, or a range consisting of any two of these values.

[0058] In a specific embodiment, the thickness of the copper layer 32 is 2 μm to 3 μm. Within this range, a higher deep drawing performance can be achieved, preventing cracks from occurring during the deep drawing process and affecting the corrosion resistance of the aluminum-plastic film.

[0059] Illustratively, the thickness of the copper layer 32 may be 2 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2.8 μm, or 3 μm, or a range consisting of any two of these values.

[0060] In a specific embodiment, the thickness of the nickel layer 33 is 0.5 μm to 1 μm. Within this range, not only can higher electrolyte corrosion resistance be achieved, but also the cost will not be affected.

[0061] Illustratively, the thickness of the nickel layer 33 may be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1 μm, or a range consisting of any two of these values.

[0062] The thickness of the composite metal layer 3 and the thickness of each layer in the composite metal layer 3 (i.e., the aluminum layer 31, the copper layer 32, and the nickel layer 33) can be measured by the following method:

[0063] Cut the aluminum plastic film into 1cm pieces 2 ×1cm 2 The cut aluminum-plastic film pieces are peeled or decomposed by mechanical peeling and / or chemical dissolution to obtain a composite metal layer 3; the peeled composite metal layer 3 is then cleaned to remove impurities (such as adhesives) remaining on the surface to avoid affecting the test results; the separated composite metal layer 3 is metallographically sectioned, and then the cross section is observed using an ultra-depth of field microscope. The thickness of each layer is measured using image analysis software ImageJ to obtain the thickness of the composite metal layer 3, the aluminum layer 31, the copper layer 32, and the nickel layer 33. The present invention does not specifically limit the method of metallographic sectioning, and conventional methods in the art can be used for sectioning.

[0064] Furthermore, phosphorus and / or tungsten can be doped into the nickel layer 33. Phosphorus can form a nickel-phosphorus alloy with nickel, and tungsten can form a nickel-tungsten alloy with nickel, thereby improving the strength and hardness of the nickel layer 33. Furthermore, the nickel-phosphorus alloy has strong resistance to corrosion by the electrolyte, thereby giving the aluminum-plastic film as a whole high mechanical strength and electrolyte resistance. At the same time, the phosphorus content or the tungsten content can also be controlled. Appropriate phosphorus and tungsten contents can further enhance the corrosion resistance of the nickel layer 33, and while ensuring high hardness of the nickel layer 33, they will not increase the brittleness or decrease the ductility of the nickel layer, thereby improving the processing performance of the aluminum-plastic film.

[0065] In a specific embodiment, the nickel layer 33 includes phosphorus and / or tungsten; the nickel layer 33 satisfies:

[0066] 6%≤A / C≤8%, and / or, 0.1%≤B / C≤1%,

[0067] Wherein, A is the mass content of phosphorus in the nickel layer 33 , B is the mass content of tungsten in the nickel layer 33 , and C is the mass content of nickel in the nickel layer 33 , and the units of A, B, and C are the same.

[0068] Specifically, the nickel layer 33 includes phosphorus, or includes tungsten, or includes both phosphorus and tungsten. When the nickel layer 33 includes phosphorus, the nickel layer 33 satisfies the following conditions: 6% ≤ A / C ≤ 8%; when the nickel layer 33 includes tungsten, the nickel layer 33 satisfies the following conditions: 0.1% ≤ B / C ≤ 1%; and when the nickel layer 33 includes both phosphorus and tungsten, the nickel layer 33 satisfies the following conditions: 6% ≤ A / C ≤ 8% and 0.1% ≤ B / C ≤ 1%.

[0069] When the nickel layer 33 includes phosphorus and the mass content ratio of phosphorus to nickel in the nickel layer 33 is within the aforementioned range, the nickel layer 33 has high resistance to electrolyte corrosion, high strength and hardness, low brittleness and high ductility, which is beneficial to improving the deformability of the aluminum-plastic film.

[0070] Illustratively, A / C may be 6%, 6.2%, 6.4%, 6.6%, 6.8%, 7%, 7.2%, 7.4%, 7.6%, 7.8% or 8%, or a range consisting of any two of these values.

[0071] When the nickel layer 33 includes tungsten and the mass content ratio of tungsten to nickel in the nickel layer 33 is within the aforementioned range, the hardness of the nickel layer 33 can be further improved, so that the plating layer has higher hardness and electrolyte corrosion resistance.

[0072] Illustratively, B / C may be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, or a range consisting of any two of these values.

[0073] In the present invention, the “mass content A of phosphorus in the nickel layer 33”, the “mass content B of tungsten in the nickel layer 33”, and the “mass content C of nickel in the nickel layer 33” can be obtained by testing using the following method:

[0074] Cut the aluminum plastic film into 1cm pieces 2 ×1cm 2 The composite metal layer 3 in the aluminum-plastic film piece is separated by a small piece. The separation method can be consistent with the test method of "the thickness of the composite metal layer 3 and the thickness of each layer in the composite metal layer 3" mentioned above; the nickel layer 33 in the cleaned composite metal layer 3 is tested by scanning electron microscopy-energy dispersive spectrum analysis (SEM-EDS) to obtain the mass content A of phosphorus element, the mass content B of tungsten element and the mass content C of nickel element in the nickel layer 33, and then the values of A / C and B / C are obtained by calculation.

[0075] Furthermore, the first passivation layer 2 and the second passivation layer 4 may also include chromium elements. The chromium-containing passivation layer usually has better corrosion resistance and can effectively protect the surface of the composite metal layer 3 from erosion by external water vapor and electrolyte; and the chromium-containing passivation layer also has good wear resistance and can effectively improve the overall mechanical strength of the aluminum-plastic film.

[0076] In a specific embodiment, the first passivation layer 2 includes chromium element, and the content of chromium element in the first passivation layer 2 is 4 mg / m 2 ~6 mg / m 2When the first passivation layer 2 includes chromium and the chromium content is within the aforementioned range, the water vapor resistance of the aluminum-plastic film can be improved.

[0077] For example, the content of chromium in the first passivation layer 2 may be 4 mg / m 2 , 4.2mg / m 2 , 4.4mg / m 2 , 4.6mg / m 2 , 4.8mg / m 2 , 5mg / m 2 , 5.2mg / m 2 , 5.4mg / m 2 , 5.6mg / m 2 , 5.8mg / m 2 or 6 mg / m 2 , or a range consisting of any two values.

[0078] In a specific embodiment, the second passivation layer 4 includes chromium elements, and the content of chromium elements in the second passivation layer 4 is 15 mg / m 2 ~20 mg / m 2 When the second passivation layer 4 includes chromium and the chromium content is within the aforementioned range, the electrolyte peeling strength of the aluminum-plastic film can be further improved.

[0079] For example, the content of chromium in the second passivation layer 4 may be 15 mg / m 2 , 15.5mg / m 2 , 16mg / m 2 , 16.5mg / m 2 , 17mg / m 2 , 17.5mg / m 2 , 18mg / m 2 , 18.5mg / m 2 , 19mg / m 2 , 19.5mg / m 2 or 20 mg / m 2 , or a range consisting of any two values.

[0080] In the present invention, the chromium content in the first passivation layer 2 and the chromium content in the second passivation layer 4 can be obtained by inductively coupled plasma optical emission spectrometry (ICP-OES) testing, which includes the following steps:

[0081] Cut the aluminum plastic film into 1cm pieces 2 ×1cm 2A small piece of aluminum-plastic film is prepared, and the first passivation layer 2 and the second passivation layer 4 are separated from the small piece of aluminum-plastic film to obtain the first passivation layer sample and the second passivation layer sample respectively. The area of the first passivation layer sample is measured as S1, and the area of the second passivation layer sample is measured as S2. The first passivation layer sample is dissolved in aqua regia, and the first liquid to be tested is obtained after filtration and clarification, and the volume of the first liquid to be tested is recorded as V1; the second passivation layer sample is dissolved in aqua regia, and the second liquid to be tested is obtained after filtration and clarification, and the volume of the second liquid to be tested is recorded as V2. Standard solutions of different concentrations are prepared (covering the concentration range of the element to be tested), and the standard solution, the first liquid to be tested, and the second liquid to be tested are tested respectively by ICP-OES. A standard curve is drawn according to the test results, and the mass concentration of chromium in the first liquid to be tested and the second liquid to be tested is calculated according to the standard curve, and the mass concentration of chromium in the first liquid to be tested is obtained as c1, and the mass concentration of chromium in the second liquid to be tested is c2. The content of chromium in the first passivation layer 2 (mg / m 2 )=(c1×V1) / S1, the content of chromium in the second passivation layer 4 (mg / m 2 )=(c2×V2) / S2.

[0082] Furthermore, the composition and thickness of the nylon layer 1 can be limited to enhance the protective effect of the nylon layer 1 on the inner layer and better resist physical impact and chemical corrosion from the outside.

[0083] In a specific embodiment, the nylon layer 1 includes nylon-based materials, and the nylon-based materials include polycaprolactam and / or polyhexamethylene adipamide.

[0084] When the nylon material includes the aforementioned multiple specific materials at the same time, the present invention does not impose any specific limitation on the ratio between the specific materials.

[0085] The present invention does not specifically limit the source of the nylon material, and any commercially available product or a product prepared by a conventional preparation method well known to those skilled in the art may be used.

[0086] In a specific embodiment, the thickness of the nylon layer 1 is 10 μm to 25 μm. Within this range, the thickness of the nylon layer 1 is relatively suitable, which can not only provide sufficient protection but also have good flexibility and heat sealing properties.

[0087] Illustratively, the thickness of the nylon layer 1 may be 10 μm, 13 μm, 16 μm, 19 μm, 22 μm or 25 μm, or a range consisting of any two of these values.

[0088] The test method for the "thickness of the nylon layer 1" in the present invention can be obtained by slicing the aluminum-plastic film along the thickness direction using a slicer and observing and measuring the end face of the slice using an ultra-depth-of-field microscope. For details, please refer to: ISO 3034: "Plastic films - Determination of thickness".

[0089] It can be understood that an adhesive layer (hereinafter referred to as the first adhesive layer) needs to be provided between the nylon layer 1 and the first passivation layer 2 to achieve mutual adhesion between the two.

[0090] In one embodiment, the first adhesive layer includes a polyurethane adhesive. When the first adhesive layer includes a polyurethane adhesive, the water vapor corrosion resistance of the aluminum-plastic film can be further improved, and the bonding strength between the nylon layer 1 and the first passivation layer 2 can be increased, thereby ensuring the stability of the aluminum-plastic film and preventing leakage.

[0091] The present invention does not specifically limit the source of the polyurethane adhesive, and any commercially available product or a product prepared by a conventional preparation method well known to those skilled in the art may be used.

[0092] In one embodiment, the thickness of the first adhesive layer is 2 μm to 5 μm, and the surface density is 2 g / m 2 ~6g / m 2 Within this range, the bonding force between the nylon layer 1 and the first passivation layer 2 can be further enhanced, thereby improving the protective effect of the nylon layer 1 on the inner layer of the aluminum-plastic film and preventing leakage.

[0093] For example, the thickness of the first adhesive layer can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or 5 μm, or a range consisting of any two values thereof; the surface density can be 2 g / m 2 , 2.5g / m 2 , 3g / m 2 3.5g / m 2 , 4g / m 2 4.5g / m 2 , 5g / m 2 , 5.5g / m 2 or 6g / m 2 , or a range consisting of any two values.

[0094] The method for measuring the thickness of the first adhesive layer in the present invention is the same as the method for measuring the thickness of the nylon layer 1 described above, and is not further described here. The areal density of the first adhesive layer can be determined by gravimetric testing in accordance with ISO 14704: "Packaging—Determination of Net Content."

[0095] Furthermore, the structure of the polypropylene layer 5 can be optimized to further enhance the electrolyte corrosion resistance of the aluminum-plastic film as a whole.

[0096] In one embodiment, the polypropylene layer 5 includes an adhesive layer and a polypropylene sublayer stacked in sequence, with the adhesive layer disposed adjacent to the second passivation layer 4. The adhesive layer comprises a maleic anhydride-modified polypropylene material, and the polypropylene sublayer comprises a polypropylene material. When the polypropylene layer 5 has the aforementioned composite structure, the adhesive layer comprises a maleic anhydride-modified polypropylene material, which can form a higher composite strength with the second passivation layer 4, thereby improving the overall electrolyte resistance of the aluminum-plastic film.

[0097] Figure 2 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment, Figure 2 In the figure, the polypropylene layer 5 includes an adhesive layer 51 and a polypropylene sublayer 52 stacked in sequence. The adhesive layer 51 is arranged on the side of the second passivation layer 4 away from the composite metal layer 3, and the polypropylene sublayer 52 is arranged on the side of the adhesive layer 51 away from the second passivation layer 4.

[0098] The present invention does not impose any particular restrictions on the specific type of polypropylene material; it can be any conventional material in the art. For example, it can be selected from at least one of a polypropylene homopolymer and a polypropylene copolymer. Furthermore, the present invention does not impose any particular restrictions on the molecular weight of the polypropylene material.

[0099] The present invention does not specifically limit the maleic anhydride modified polypropylene material or the source of the polypropylene material. Any commercially available product or a product prepared by a conventional preparation method known to those skilled in the art can be used.

[0100] Furthermore, the grafting rate of maleic anhydride in the maleic anhydride-modified polypropylene material has a certain influence on the electrolyte peeling strength of the aluminum-plastic film. A suitable grafting rate is beneficial to improving the electrolyte peeling strength of the aluminum-plastic film.

[0101] In a specific embodiment, the grafting rate of maleic anhydride in the maleic anhydride-modified polypropylene material is 0.5% to 3.5%. Within this range, the electrolyte peeling strength between the composite metal layer 3 and the polypropylene layer 5 can be further improved.

[0102] For example, the grafting rate of maleic anhydride in the maleic anhydride modified polypropylene material can be 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0% or 3.5%, or a range consisting of any two of these values.

[0103] The "grafting rate of maleic anhydride in the maleic anhydride-modified polypropylene material" in the present invention can be obtained by Fourier transform infrared spectroscopy (FT-IR) testing. The testing standard refers to ISO 16014-1: "Polymer modified materials - Characterization of maleic anhydride-grafted polyolefins".

[0104] In one embodiment, the melting point of the adhesive layer 51 is 140°C to 150°C, and the melt index is 2g / 10min to 10g / 10min. Within this range, the high temperature resistance and corrosion resistance of the aluminum-plastic film are improved without affecting the bonding temperature between the adhesive layer 51 and the composite metal layer 3.

[0105] Exemplarily, the melting point of the adhesive layer 51 can be 140°C, 142°C, 144°C, 146°C, 148°C or 150°C, or a range consisting of any two of these values; the melt index can be 2g / 10min, 4g / 10min, 6g / 10min, 8g / 10min or 10g / 10min, or a range consisting of any two of these values.

[0106] In a specific embodiment, the polypropylene sublayer 52 includes a first polypropylene sublayer and a second polypropylene sublayer stacked in sequence, and the first polypropylene sublayer is arranged close to the adhesive layer 51; preferably, the melting point of the first polypropylene sublayer is 160°C to 170°C, and the melt index is 2g / 10min to 5g / 10min, and the melting point of the second polypropylene sublayer is 135°C to 145°C, and the melt index is 5g / 10min to 10g / 10min.

[0107] The first polypropylene sublayer, serving as the core layer, primarily functions as an ion barrier. When the melting point and melt index of the first polypropylene sublayer are within the aforementioned ranges, it not only exhibits a high ion barrier effect (for example, against lithium ions in batteries), but also does not affect the corrosion resistance of the aluminum-plastic film. The second polypropylene sublayer, serving as a heat-sealing layer, primarily functions as an encapsulation layer. When the melting point and melt index of the second polypropylene sublayer are within the aforementioned ranges, it achieves high encapsulation performance without generating excessive heat radiation that could affect the corrosion resistance of the aluminum-plastic film.

[0108] Exemplarily, the melting point of the first polypropylene sublayer can be 160°C, 162°C, 164°C, 166°C, 168°C or 170°C, or a range consisting of any two values therein; the melt index can be 2 g / 10min, 2.5 g / 10min, 3 g / 10min, 3.5 g / 10min, 4 g / 10min, 4.5 g / 10min or 5 g / 10min, or a range consisting of any two values therein.

[0109] Illustratively, the melting point of the second polypropylene sublayer can be 135°C, 137°C, 139°C, 141°C, 143°C or 145°C, or a range consisting of any two values therein; the melt index can be 5 g / 10min, 6 g / 10min, 7 g / 10min, 8 g / 10min, 9 g / 10min or 10 g / 10min, or a range consisting of any two values therein.

[0110] The test method for "melting point" in the present invention can refer to: ASTM D3418: Standard Test Method for Determination of Melting Temperature of Polymers by DSC; the test method for "melt index" can refer to: ASTM D1238: Standard Test Method for Melt Flow Rate of Plastics.

[0111] Figure 3 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment, Figure 3 In the figure, the polypropylene sublayer 52 includes a first polypropylene sublayer 521 and a second polypropylene sublayer 522 stacked in sequence, wherein the first polypropylene sublayer 521 is arranged on the side of the adhesive layer 51 away from the second passivation layer 4, and the second polypropylene sublayer 522 is arranged on the side of the first polypropylene sublayer 521 away from the adhesive layer 51.

[0112] Furthermore, the thicknesses of the adhesive layer 51 , the first polypropylene sublayer 521 and the second polypropylene sublayer 522 in the polypropylene layer 5 can be controlled to make the aluminum-plastic film have higher heat sealing performance and heat resistance.

[0113] In one specific embodiment, the thickness ratio of the adhesive layer 51, the first polypropylene sublayer 521, and the second polypropylene sublayer 522 is (0.7-1.5):(6-8):(0.5-1.5). Preferably, the thickness of the polypropylene layer 5 is 60 μm to 80 μm. When the thickness ratio of each layer in the polypropylene layer 5 is within the aforementioned range, the thickness of the adhesive layer 51, the first polypropylene sublayer 521, and the second polypropylene sublayer 522 is more appropriate, which can improve the overall performance of the aluminum-plastic film. Furthermore, when the thickness of the polypropylene layer 5 is within the aforementioned range, it is beneficial to improve the insulation performance and sealing strength of the aluminum-plastic film for the battery.

[0114] Illustratively, the thickness ratio of the adhesive layer 51, the first polypropylene sublayer 521 and the second polypropylene sublayer 522 can be 0.7:6:0.5, 0.7:8:1.5, 0.7:6:1.5, 0.7:8:0.5, 1.5:6:0.5, 1.5:8:1.5, 1.5:6:1.5, 1.5:8:0.5, 1:7:1, 1:6:0.5, 1:8:0.8, 1:6:1.5, 1:8:0.5, 1:8:1.5, 0.7:7:0.5, 1.5:7:0.5, 1:7:1.5, 1:7:0.5, etc.

[0115] Illustratively, the thickness of the polypropylene layer 5 may be 60 μm, 62 μm, 64 μm, 66 μm, 68 μm, 70 μm, 72 μm, 74 μm, 76 μm, 78 μm or 80 μm, or a range consisting of any two of these values.

[0116] The method for measuring the thickness of the polypropylene layer 5 and each layer therein (including the adhesive layer 51, the first polypropylene sublayer 521 and the second polypropylene sublayer 522) in the present invention can be consistent with the method for measuring the thickness of the nylon layer 1, which will not be repeated here.

[0117] Furthermore, in order to prevent the nylon layer 1 from being corroded by the electrolyte and to make the aluminum-plastic film have higher structural stability and barrier properties, a polyethylene terephthalate layer (ie, PET layer) may be added.

[0118] In a specific embodiment, the aluminum-plastic film further includes a polyethylene terephthalate layer, and the polyethylene terephthalate layer is disposed on a side of the nylon layer 1 away from the first passivation layer 2 .

[0119] Figure 4 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment, Figure 4 In the embodiment, the aluminum-plastic film further includes a polyethylene terephthalate layer 6 , wherein the polyethylene terephthalate layer 6 is arranged on a side of the nylon layer 1 away from the first passivation layer 2 .

[0120] Furthermore, the thickness of the polyethylene terephthalate layer 6 also has a certain impact on the deep-drawing performance and structural stability of the aluminum-plastic film. A suitable thickness can not only enhance its protective performance, but also avoid the problems of increased weight, decreased flexibility and increased cost caused by excessive thickness.

[0121] In one embodiment, the thickness of the polyethylene terephthalate layer 6 is 1.5 μm to 4.5 μm. Within this range, the thickness of the polyethylene terephthalate layer 6 is relatively suitable, which not only further improves the deep-drawing performance of the aluminum-plastic film, but also provides sufficient strength and rigidity to effectively protect the inner layer of the aluminum-plastic film. It also has good flexibility to prevent leakage at the folded edge.

[0122] Illustratively, the thickness of the polyethylene terephthalate layer 6 may be 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm or 4.5 μm, or a range consisting of any two of these values.

[0123] The "thickness of the polyethylene terephthalate layer 6" in the present invention can be consistent with the test method of the "thickness of the nylon layer 1" described above, and will not be described in detail here.

[0124] It is understandable that an adhesive layer (hereinafter referred to as the second adhesive layer) needs to be provided between the nylon layer 1 and the polyethylene terephthalate layer 6 to achieve mutual adhesion between the two.

[0125] In one embodiment, the second adhesive layer includes a polyurethane adhesive. When the second adhesive layer includes a polyurethane adhesive, the water vapor corrosion resistance of the aluminum-plastic film can be further improved, and the bonding strength between the polyethylene terephthalate layer 6 and the nylon layer 1 can be improved, thereby ensuring the stability of the aluminum-plastic film.

[0126] In one embodiment, the thickness of the second adhesive layer is 2 μm to 5 μm, and the surface density of the second adhesive layer is 2 g / m 2 ~6g / m 2 When the thickness and surface density of the second adhesive layer are within the aforementioned ranges, the bonding strength between the polyethylene terephthalate layer 6 and the nylon layer 1 can be effectively improved, further enhancing the structural stability of the aluminum-plastic film and preventing leakage.

[0127] For example, the thickness of the second adhesive layer can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or 5 μm, or a range consisting of any two values thereof; the surface density can be 2 g / m 2 , 2.5g / m 2 , 3g / m 2 3.5g / m 2 , 4g / m 2 4.5g / m 2 , 5g / m 2 , 5.5g / m 2 or 6g / m 2 , or a range consisting of any two values.

[0128] The measurement method of the "thickness of the second adhesive layer" in the present invention can be consistent with the test method of the above-mentioned "thickness of the nylon layer 1", which will not be repeated here; the measurement method of the "surface density of the second adhesive layer" can be consistent with the measurement method of the above-mentioned "surface density of the first adhesive layer", which will not be repeated here.

[0129] Furthermore, the surface of the nickel layer 33 may include a sealing layer comprising a silane coupling agent. This sealing layer not only seals the pores in the nickel layer, effectively isolating it from the external electrolyte and improving the corrosion resistance of the composite metal layer to the electrolyte, but also increases the hardness and wear resistance of the nickel layer 33 to a certain extent.

[0130] In one specific embodiment, the aluminum-plastic film further includes a sealing layer disposed between the composite metal layer 3 and the second passivation layer 4; the sealing layer includes a silane coupling agent; preferably, the silane coupling agent includes at least one of polyacrylic resin, aminosilane coupling agent, vinylsilane coupling agent, and epoxysilane coupling agent. The epoxysilane coupling agent includes epoxy resin.

[0131] When the silane coupling agent includes multiple specific materials among the above materials, the present invention does not specifically limit the ratio between the specific materials.

[0132] Figure 5 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment, Figure 6 Schematic diagram of the structure of the aluminum-plastic film of the present invention in one embodiment, Figure 5 and Figure 6 In the embodiment, the sealing layer 7 is arranged between the composite metal layer 3 and the second passivation layer 4 .

[0133] The present invention does not impose any specific limitation on the thickness of the sealing layer, and it can be adjusted according to actual conditions.

[0134] A second aspect of the present invention provides a method for preparing the aluminum-plastic film of the first aspect, comprising the following steps:

[0135] Copper and aluminum materials are compounded to obtain a copper-aluminum composite layer; the surface of the copper layer in the copper-aluminum composite layer is then nickel-plated to obtain a composite metal layer; a first passivation layer and a nylon layer are sequentially stacked on the aluminum layer side of the composite metal layer, and a second passivation layer and a polypropylene layer are sequentially stacked on the nickel layer side of the composite metal layer to obtain an aluminum-plastic film.

[0136] Specifically, in one embodiment, the method comprises the following steps: compounding a copper material and an aluminum material to obtain a desired copper-aluminum composite layer; applying a protective film to the surface of the aluminum layer in the copper-aluminum composite layer (the surface refers to the side surface of the aluminum layer away from the copper layer) to prevent the nickel layer from being deposited on the surface of the aluminum layer during the subsequent nickel plating process; then nickel plating the copper-aluminum composite layer with the protective film, and depositing nickel on the surface of the copper layer (the surface refers to the side surface of the copper layer away from the aluminum layer) to form a nickel layer to obtain a composite metal layer; the composite metal layer comprises a stacked aluminum layer, a copper layer, and a nickel layer. Subsequently, a passivation coating is prepared and applied to both sides of the composite metal layer, and after baking, a first passivation layer and a second passivation layer are formed, respectively, wherein the first passivation layer is located on the surface of the aluminum layer (the surface refers to the surface of the aluminum layer away from the copper layer), and the second passivation layer is located on the surface of the nickel layer (the surface refers to the surface of the nickel layer away from the copper layer). Then, the first passivation layer is laminated to the nylon layer, and the second passivation layer is laminated to the polypropylene layer. Finally, an aging process is performed to obtain an aluminum-plastic film.

[0137] The method for preparing the aluminum-plastic film of the present invention comprises cold-rolling a copper material and an aluminum material to obtain a copper-aluminum composite layer. The copper layer can effectively improve the surface potential of the aluminum layer, blocking electrochemical corrosion during leakage, thereby improving the leakage safety of the battery. Simultaneously, in order to effectively form a passivation layer (i.e., a first passivation layer and a second passivation layer) on both sides of the copper-aluminum composite layer, a nickel plating process is performed on the surface of the copper layer. The passivation layer can effectively suppress the reaction between the electrolyte and the aluminum layer. Furthermore, by providing a nylon layer on the side of the first passivation layer away from the composite metal layer and a polypropylene layer on the side of the second passivation layer away from the composite metal layer, it is ensured that the prepared aluminum-plastic film has high electrochemical corrosion resistance, while meeting application requirements, effectively improving the problem of battery leakage failure.

[0138] The present invention does not specifically limit the specific material of the copper material, and commonly used materials in this field can be used; preferably, at least one of CU1020, CU1011, CU1221, and CU1201 is selected.

[0139] The present invention does not impose any special restrictions on the specific material of the aluminum material, and materials commonly used in the art can be used; preferably, 8021 system aluminum material is selected.

[0140] The present invention does not specifically limit the sources of the copper and aluminum materials, and commercially available products or products prepared by conventional preparation methods well known to those skilled in the art may be used.

[0141] The main function of the "protective film" in the present invention is to prevent the nickel layer from being deposited on the surface of the aluminum layer during the subsequent nickel plating process. The present invention does not specifically limit the specific material of the protective film, for example, a release film can be selected.

[0142] The present invention does not specifically limit the nickel plating method, as long as a nickel layer can be formed on the surface of the copper layer; for example, the treatment can be performed by any one of pulse nickel plating, direct current nickel plating and chemical nickel plating.

[0143] In one embodiment, the nickel plating treatment includes the following steps: sequentially performing an alkaline washing treatment, a first water washing treatment, an electroplating treatment, a second water washing treatment, and a baking treatment on the copper-aluminum composite layer to obtain a composite metal layer.

[0144] It can be understood that the main function of the alkaline washing treatment is to remove dirt and oxide film on the surface of the copper-aluminum composite layer, so as to expose the metal substrate and lay a good foundation for subsequent electroplating.

[0145] The present invention does not specifically limit the method of alkali washing treatment, and conventional methods in the art can be used for treatment. Preferably, the pH of the alkali solution in the alkali washing treatment is 9.0 to 11.0. Exemplarily, the pH of the alkali solution is 9.0, 9.5, 10.0, 10.5 or 11.0, or a range consisting of any two of these values.

[0146] The main purpose of the first water washing treatment is to clean the alkali solution on the surface of the copper-aluminum composite layer to avoid affecting the subsequent electroplating treatment.

[0147] The present invention does not specifically limit the method of the first water washing treatment, and conventional methods in the art can be used for treatment, and it is only necessary to thoroughly clean the alkaline solution on the surface of the copper-aluminum composite layer.

[0148] Electroplating is the process of depositing a nickel layer on the surface of the workpiece (i.e., the copper layer of the composite metal layer) under the action of an electric current. It is understood that electroplating requires an electrolytic device, which includes an electroplating tank, an electroplating solution, the workpiece to be plated, an anode, and a power supply to the electroplating tank.

[0149] The present invention does not impose any specific restrictions on the components of the electroplating solution and the content of each component. It only needs to be able to provide nickel metal ions and form a nickel layer on the surface of the copper layer.

[0150] Furthermore, during the electroplating process, the thickness of the nickel layer can be controlled by controlling the pulling speed, electroplating temperature and current density; preferably, the pulling speed is 3m / min to 5m / min, the electroplating temperature is 40℃ to 60℃, and the current density is 45A / dm 2 ~60A / dm 2 Within this range, it is helpful to make the thickness of the deposited nickel layer between 0.5 μm and 1 μm.

[0151] For example, the pulling speed can be 3 m / min, 3.5 m / min, 4 m / min, 4.5 m / min or 5 m / min, or a range consisting of any two values therein; the electroplating temperature can be 40°C, 44°C, 48°C, 52°C, 56°C or 60°C, or a range consisting of any two values therein; the current density can be 45 A / dm 2 、48A / dm 2 , 51A / dm 2 , 54A / dm 2 、57A / dm 2 or 60A / dm 2 , or a range consisting of any two values.

[0152] The purpose of the second water washing treatment is to clean the plating solution on the surface of the composite metal layer, prevent the plating solution from corroding the coating, and prevent the plating solution from being used in subsequent treatments.

[0153] The present invention does not specifically limit the method of the second water washing treatment, and conventional methods in the art can be used for the treatment, and it is only necessary to thoroughly clean the plating solution on the surface of the composite metal layer.

[0154] The purpose of baking treatment is, on the one hand, to remove hydrogen atoms that may penetrate into the coating during the electroplating process, to prevent the material from becoming brittle and cracks caused by brittleness; on the other hand, to remove moisture on the surface and inside of the coating.

[0155] Preferably, the baking temperature in the baking process is 100° C. to 110° C. For example, the baking temperature may be 100° C., 102° C., 104° C., 106° C., 108° C., or 110° C., or a range consisting of any two values thereof.

[0156] The present invention does not impose any specific restrictions on the baking time, and a suitable baking time can be selected according to actual conditions. For example, the baking time is 1 minute to 2 minutes.

[0157] In one embodiment, during the electroplating process, the plating solution includes a soluble nickel salt, and the soluble nickel salt includes at least one of nickel sulfamate, nickel sulfate, nickel nitrate, and nickel chloride; preferably, the soluble nickel salt includes nickel sulfamate.

[0158] When nickel sulfamate is included in the plating solution, it helps to form a more uniform nickel layer with moderate hardness.

[0159] When the plating solution includes multiple specific soluble nickel salts mentioned above at the same time, the present invention does not impose any special restrictions on the ratio between the various soluble nickel salts.

[0160] The present invention does not specifically limit the source of the aforementioned soluble nickel salt, and any commercially available product or a product prepared by a conventional preparation method well known to those skilled in the art may be used.

[0161] The present invention does not specifically limit the content of the soluble nickel salt in the plating solution, and the content of the soluble nickel salt in the plating solution can be controlled according to actual conditions; for example, the content of the soluble nickel salt in the plating solution is 0.5 mol / L to 3 mol / L.

[0162] In one embodiment, the plating solution further includes a soluble tungstate and / or a nickel-phosphorus additive; the soluble tungstate includes at least one of sodium tungstate, potassium tungstate, and ammonium tungstate, and the nickel-phosphorus additive includes at least one of phosphorous acid, hypophosphorous acid, and hypophosphite. Preferably, the mass content of the soluble tungstate in the plating solution is 0.5% to 2%. Specifically, the nickel-phosphorus additive includes SHM-626 High-Efficiency Nickel-Phosphorus Agent A and / or SHM-626 High-Efficiency Nickel-Phosphorus Agent B.

[0163] For example, the mass content of the soluble tungstate in the plating solution may be 0.5%, 1%, 1.5% or 2%, or a range consisting of any two of these values.

[0164] Specifically, the plating solution includes soluble tungstate, or the plating solution includes nickel-phosphorus additive, or the plating solution includes both soluble tungstate and nickel-phosphorus additive.

[0165] Soluble tungsten salts in the plating solution can form a nickel-tungsten alloy during the electroplating process and deposit on the surface of the copper layer. Under the action of tungsten, the nickel layer can be denser, harder, and have better corrosion resistance. Furthermore, when the mass content of soluble tungstate in the plating solution is 0.5% to 2%, it helps to keep the mass content of tungsten in the nickel layer between 0.1% and 1%. Under the premise of ensuring the hardness and corrosion resistance of the coating, it can avoid the increase in coating roughness caused by excessive content.

[0166] The nickel-phosphorus additive in the plating solution forms a nickel-phosphorus alloy during the electroplating process and deposits on the surface of the copper layer. This not only improves the strength and hardness of the nickel layer, but also enhances its corrosion resistance to the electrolyte, thereby improving the overall performance of the aluminum-plastic film. Furthermore, the phosphorus content of the nickel layer can be controlled to between 6% and 8% by weight by weight by controlling the content of the nickel-phosphorus additive in the plating solution. Preferably, the content of the nickel-phosphorus additive in the plating solution is between 0.5 mol / L and 3 mol / L.

[0167] When the plating solution includes multiple specific soluble tungstates mentioned above at the same time, the present invention does not impose any special restrictions on the ratio between the various soluble tungstates.

[0168] When the plating solution includes multiple specific nickel-phosphorus additives mentioned above at the same time, the present invention does not impose any special restrictions on the ratio between the specific nickel-phosphorus additives.

[0169] The present invention does not specifically limit the sources of the soluble tungstate and nickel-phosphorus additives; commercially available products or products prepared by conventional preparation methods well known to those skilled in the art may be used.

[0170] Furthermore, before the baking treatment, the copper-aluminum composite layer after the second water washing treatment can be treated with a sealant to form a sealing layer on the surface of the nickel layer (the surface refers to the side of the nickel layer away from the copper layer), which can fill the pores in the nickel layer, effectively isolate the external electrolyte, improve the corrosion resistance of the composite metal layer to the electrolyte, and also increase the hardness and wear resistance of the nickel layer to a certain extent.

[0171] In one embodiment, the sealant treatment comprises the following steps:

[0172] The copper-aluminum composite layer after the second water washing treatment is immersed in a sealant for 1 to 2 minutes; wherein the sealant includes a silane coupling agent, and the silane coupling agent includes at least one of polyacrylic resin, aminosilane coupling agent, vinylsilane coupling agent, and epoxysilane coupling agent (such as epoxy resin).

[0173] By treating the copper-aluminum composite layer after the nickel plating layer with a sealant, not only can the corrosion resistance of the composite metal layer to the electrolyte be effectively improved, but also the hardness and wear resistance of the nickel layer can be improved.

[0174] The present invention does not impose any specific limitation on the composition of the passivation coating, as long as it can play a passivation role, and a first passivation layer and a second passivation layer are respectively formed on both sides of the composite metal layer.

[0175] The present invention does not impose any specific restrictions on the coating speed of the passivation coating, and a suitable coating speed can be selected according to actual conditions. Preferably, the coating speed is 10 m / min to 20 m / min. For example, the coating speed is 10 m / min, 12 m / min, 14 m / min, 16 m / min, 18 m / min, or 20 m / min, or a range consisting of any two of these values.

[0176] The present invention does not impose any specific restrictions on the baking temperature of the passivation coating, and a suitable baking temperature can be selected according to actual conditions. Preferably, the baking temperature is 120°C to 200°C. For example, the baking temperature can be 120°C, 140°C, 160°C, 180°C, or 200°C, or a range consisting of any two of these values.

[0177] Furthermore, the passivation coating may also include soluble chromate, which can undergo redox reaction with the aluminum and nickel in the composite metal layer to form a first passivation layer on the surface of the aluminum layer and a second passivation layer on the surface of the nickel layer, respectively, thereby effectively improving the corrosion resistance and wear resistance of the composite metal layer, thereby improving the overall electrolyte corrosion resistance and mechanical strength of the aluminum-plastic film.

[0178] Preferably, the passivation coating may also include a film-forming additive, which includes at least one of a water-based polyacrylic resin, a water-based polyolefin resin, and a water-based polyurethane organic resin. The film-forming additive can form a stable chemical bond with the aluminum layer and the nickel layer, enhance the adhesion and durability of the first passivation layer and the second passivation layer, and at the same time improve the flexibility and crack resistance of the first passivation layer and the second passivation layer, so that the first passivation layer and the second passivation layer have higher stability. In addition, the mass content of the film-forming additive in the passivation coating can be controlled to improve the overall performance of the passivation layer; the appropriate mass content can not only make the first passivation layer and the second passivation layer have higher adhesion, durability and flexibility, but also avoid the first passivation layer and the second passivation layer being too soft due to excessive film-forming additives, affecting mechanical properties, and avoid the adhesion between the first passivation layer and the aluminum layer, and between the second passivation layer and the nickel layer. In addition, the uniformity of the passivation coating during coating can be improved, which is convenient for processing.

[0179] In one embodiment, the soluble chromate includes at least one of potassium chromate, potassium dichromate, sodium chromate, ammonium chromate, and zinc chromate; the film-forming additive includes at least one of sodium chloride, nickel chloride, zinc chloride, and chromium chloride; preferably, the mass content of the film-forming additive in the passivation coating is 1% to 5%.

[0180] For example, the mass content of the film-forming additive in the passivation coating can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, or a range consisting of any two of these values.

[0181] When the passivation coating includes a soluble chromate, the composite metal layer can have higher corrosion resistance and wear resistance, thereby improving the overall electrolyte corrosion resistance and mechanical strength of the aluminum-plastic film. Furthermore, when the passivation coating also includes the aforementioned film-forming additive, the first and second passivation layers can have higher adhesion, durability, and flexibility, improving the stability of the passivation layers. By controlling the mass content of the film-forming additive in the passivation coating to fall within the aforementioned range, not only can the high stability of the first and second passivation layers be ensured, but the processing performance of the passivation coating can also be improved.

[0182] The present invention does not impose any specific restrictions on the mass content of the soluble chromate in the passivation coating, and it can be adjusted according to actual conditions. Furthermore, by controlling the coating amount of the passivation coating on both sides of the composite metal layer, or the mass content of the soluble chromate in the passivation coating, the chromium content in the first passivation layer can be adjusted to 4 mg / m 2 ~6 mg / m 2 The chromium content in the second passivation layer is 15 mg / m 2 ~20 mg / m 2 Preferably, the coating amount of the passivation coating on the aluminum layer surface in the composite metal layer is 3g / m 2 ~10g / m 2 The coating amount of the passivation coating on the nickel layer surface in the composite metal layer is 10g / m 2 ~30g / m 2 Preferably, the mass content of the soluble chromate in the passivation coating is 1% to 10%.

[0183] For example, the coating amount of the passivation coating on the aluminum layer surface in the composite metal layer can be 3g / m 2 , 4g / m 2 , 5g / m 2 , 6g / m 2 , 7g / m 2 , 8g / m 2 , 9g / m 2 or 10g / m 2, or a range consisting of any two values thereof; the coating amount of the passivation coating on the surface of the nickel layer in the composite metal layer can be 10g / m 2 , 12g / m 2 , 14g / m 2 , 16g / m 2 , 18g / m 2 , 20g / m 2 , 22g / m 2 , 24g / m 2 , 26g / m 2 , 28g / m 2 or 30g / m 2 , or a range consisting of any two of the values therein; the mass content of soluble chromate in the passivation coating can be 1%, 2%, 4%, 6%, 8% or 10%, or a range consisting of any two of the values therein.

[0184] It should be noted that when the soluble chromate comprises multiple of the aforementioned materials, the present invention does not impose any specific restrictions on the ratios between the materials. When the film-forming additive comprises multiple of the aforementioned materials, the present invention does not impose any specific restrictions on the ratios between the materials.

[0185] The present invention does not specifically limit the sources of the soluble chromate and the film-forming additive, and commercially available products or products prepared by conventional preparation methods well known to those skilled in the art may be used.

[0186] The present invention does not specifically limit the aging conditions (including aging temperature and aging time), and appropriate aging conditions can be selected based on actual conditions. Preferably, the aging temperature is 60°C to 80°C, and the aging time is 3 to 7 days. For example, the aging temperature is 60°C, 65°C, 70°C, 75°C, or 80°C, or a range consisting of any two thereof; and the aging time is 3 days, 4 days, 5 days, 6 days, or 7 days, or a range consisting of any two thereof.

[0187] The "aging" in the present invention refers to the process of being placed under certain temperature conditions for a period of time.

[0188] It should be noted that the method of bonding the first passivation layer and the nylon layer includes: applying a first adhesive (corresponding to forming a first adhesive layer) on the surface of the first passivation layer (the surface refers to the surface of the first passivation layer away from the aluminum layer), and bonding it with the nylon layer after baking.

[0189] The present invention does not impose any specific restrictions on the coating speed of the first adhesive, and a suitable coating speed can be selected according to actual conditions. Preferably, the coating speed is 10 m / min to 20 m / min. For example, the coating speed is 10 m / min, 12 m / min, 14 m / min, 16 m / min, 18 m / min, or 20 m / min, or a range consisting of any two of these values.

[0190] The present invention does not impose any specific limitation on the coating amount of the first adhesive, which can be controlled according to actual conditions. Furthermore, the thickness and surface density of the first adhesive layer in the aluminum-plastic film can be controlled by controlling the coating amount of the first adhesive.

[0191] The present invention does not impose any specific restrictions on the baking temperature of the first binder, and a suitable baking temperature can be selected according to actual conditions. Preferably, the baking temperature can be 60°C to 120°C. For example, the baking temperature can be 60°C, 80°C, 100°C, or 120°C, or a range consisting of any two of these values.

[0192] The present invention does not impose any specific restrictions on the lamination speed and temperature of the first adhesive layer and the nylon layer, and they can be adjusted according to actual conditions. Preferably, the lamination speed can be 10 to 20 m / min, and the lamination temperature can be 60°C to 120°C. For example, the lamination speed can be 10 m / min, 12 m / min, 14 m / min, 16 m / min, 18 m / min, or 20 m / min, or a range consisting of any two thereof; the lamination temperature can be 60°C, 80°C, 100°C, or 120°C, or a range consisting of any two thereof.

[0193] In a specific embodiment, the copper material and the aluminum material are composited by cold rolling, and the cold rolling includes:

[0194] Copper and aluminum materials are used as raw materials, and the raw materials are pretreated to remove surface oxides and impurities; the pretreated raw materials are sent to the cold rolling unit, and undergo multiple continuous cold rolling processes to gradually reduce the thickness. After reaching the designed thickness, annealing treatment is performed to obtain a copper-aluminum composite layer.

[0195] In a specific embodiment, after the first cold rolling, the deformation of the raw material is not less than 65%. When the deformation after the first cold rolling is not less than 65%, it is helpful to improve the peeling force between the copper layer and the aluminum layer.

[0196] Illustratively, the deformation amount of the raw material may be 65%, 70%, 75%, 80% or 85%, or a range consisting of any two values therein.

[0197] The “deformation variable” in the present invention can be calculated by formula 1:

[0198] Deformation (%) = (W0-W1) / W0×100% Formula 1

[0199] In Formula 1, W0 is the total thickness of the copper material and the aluminum material before cold rolling, and W1 is the total thickness of the copper material and the aluminum material after cold rolling.

[0200] In a specific embodiment, the annealing temperature is 300° C. to 500° C. and the annealing time is 2 hours to 8 hours. Within this range, the composite metal layer can be guaranteed to have a suitable hardness.

[0201] Illustratively, the annealing temperature may be 300°C, 350°C, 400°C, 450°C or 500°C, or a range consisting of any two of these values; the annealing time may be 2h, 3h, 4h, 5h, 6h, 7h or 8h, or a range consisting of any two of these values.

[0202] Furthermore, before the aging treatment, a polyethylene terephthalate layer can be provided on the surface of the nylon layer to make the aluminum-plastic film have higher structural stability and barrier properties.

[0203] In a specific embodiment, a polyethylene terephthalate layer is disposed on a side of the nylon layer away from the first passivation layer.

[0204] It is understood that during the preparation of the aluminum-plastic film, a second adhesive (corresponding to forming a second adhesive layer) can be coated on the surface of the nylon layer (the surface refers to the surface of the nylon layer away from the first passivation layer), and then laminated to the polyethylene terephthalate layer after baking.

[0205] The present invention does not impose any specific restrictions on the baking temperature of the second adhesive, and a suitable baking temperature can be selected according to actual conditions. Preferably, the baking temperature is 60°C to 120°C. Within this range, the bonding strength between the polyethylene terephthalate layer and the nylon layer is improved.

[0206] Illustratively, the baking temperature may be 60° C., 80° C., 100° C., or 120° C., or a range consisting of any two values thereof.

[0207] The present invention does not impose any specific restrictions on the coating speed of the second adhesive, and a suitable coating speed can be selected according to actual conditions. Preferably, the coating speed is 10 m / min to 25 m / min. For example, the coating speed is 10 m / min, 13 m / min, 16 m / min, 19 m / min, 22 m / min, or 25 m / min, or a range consisting of any two of these values.

[0208] The present invention does not impose any specific restrictions on the coating amount of the second adhesive, which can be controlled according to actual conditions. Furthermore, the thickness and surface density of the second adhesive layer in the aluminum-plastic film can be controlled by controlling the coating amount of the second adhesive.

[0209] The present invention does not specifically limit the lamination speed and lamination temperature when laminating to the polyethylene terephthalate layer after baking, and can be adjusted according to actual conditions. Preferably, the lamination speed is 10m / min to 25m / min, and the lamination temperature is 25°C to 50°C.

[0210] For example, the laminating speed can be 10 m / min, 13 m / min, 16 m / min, 19 m / min, 22 m / min or 25 m / min, or a range consisting of any two values therein; the laminating temperature is 25°C, 30°C, 35°C, 40°C, 45°C or 50°C, or a range consisting of any two values therein.

[0211] A third aspect of the present invention provides a battery. Since the battery comprises the aluminum-plastic film of the first aspect or the aluminum-plastic film prepared by the preparation method of the second aspect, the battery has high safety.

[0212] It is understood that the battery further includes a positive electrode, a negative electrode, and an electrolyte housed in the aluminum-plastic film. When the aluminum-plastic film includes a nylon layer, a first passivation layer, a composite metal layer, a second passivation layer, and a polypropylene layer stacked in sequence, and the composite metal layer includes an aluminum layer, a copper layer, and a nickel layer stacked in sequence, the nylon layer is located on the side away from the positive electrode, the negative electrode, and the electrolyte, and the polypropylene layer is located on the side closer to the positive electrode, the negative electrode, and the electrolyte; that is, from the interior of the battery to the exterior, the aluminum-plastic film includes, in sequence, the polypropylene layer, the second passivation layer, the nickel layer, the copper layer, the aluminum layer, the first passivation layer, and the nylon layer.

[0213] It should be noted that the battery in the present invention can be a soft-pack battery or a blade battery; specifically, the battery can be any alkali metal ion battery, such as a lithium-ion battery or a sodium-ion battery. Specifically, the battery can be a liquid battery using a liquid electrolyte, or a solid-state battery or a semi-solid-state battery. The positive electrode, negative electrode, and electrolyte in the battery can be any known positive electrode, negative electrode, and electrolyte in the corresponding battery.

[0214] A fourth aspect of the present invention provides a battery pack comprising the aluminum-plastic film of the first aspect, or the aluminum-plastic film prepared by the preparation method of the second aspect, or the battery of the third aspect.

[0215] Generally, a battery pack includes multiple (at least two) of the above-mentioned batteries, which are connected as single cells to form a battery pack. These batteries can be electrically connected using conventional methods in the art, such as series connection, parallel connection, or a combination of these connection methods, without particular limitation.

[0216] The fifth aspect of the present invention provides an electrical device, comprising the aluminum-plastic film of the first aspect, or the aluminum-plastic film prepared by the preparation method of the second aspect, or the battery of the third aspect, or the battery pack of the fourth aspect, so that the electrical device has a long service life and high safety.

[0217] The present invention does not specifically limit the specific types of electrical devices, including but not limited to 3C electronic consumer products such as mobile phones, laptops, tablets, smart watches, etc.

[0218] Hereinafter, the aluminum-plastic film and the battery including the aluminum-plastic film provided by the present invention will be described in detail through specific embodiments.

[0219] Example 1

[0220] 1) Preparation of copper-aluminum composite layer:

[0221] The raw materials used were CU1020 copper and 8021 aluminum. Before rolling, the aluminum foil had a thickness of 275 μm and the copper foil had a thickness of 12 μm. The raw materials were pickled to remove surface oxides and oil stains. The pretreated raw materials were then fed into a cold rolling mill, where the deformation after the first cold rolling pass was controlled at 70%. After four consecutive cold rolling passes, the thickness reached the designed value of 57.4 μm. The copper-aluminum composite layer was then annealed at 300°C for 3 hours.

[0222] 2) Preparation of composite metal layer:

[0223] A release film is attached to the surface of the aluminum layer in the copper-aluminum composite layer prepared above, and then alkali washing, water washing, electroplating, water washing, sealant treatment, and baking are carried out in sequence to obtain a composite metal layer; wherein the pH of the alkali solution in the alkali washing is 10.0, the plating solution in the electroplating comprises nickel sulfamate (mass concentration of 2.5 mol / L), sodium tungstate (mass content in the plating solution is 2%), and a nickel-phosphorus additive (brand: SHM-626 high-efficiency nickel-phosphorus agent A, mass concentration of 3 mol / L), the pulling speed is 4 m / min, the electroplating temperature is 50°C, and the current density is 50 A / dm 2 The baking temperature is 105°C; the sealing agent is dodecyltrimethoxysilane, and the immersion time in the sealing agent is 1 minute.

[0224] 3) Formation of passivation layer:

[0225] Potassium dichromate, a film-forming additive (sodium chloride), a stabilizer (ethanol), a complexing agent (citric acid) and water are uniformly mixed to obtain a passivation coating, wherein the mass content of potassium dichromate is 8% and the mass content of sodium chloride is 2%; subsequently, the release film in the composite metal layer is peeled off, and the passivation coating is applied to both sides of the composite metal layer at a coating speed of 15 m / min; then, the layers are baked at 140°C for 0.4 min, 160°C for 0.4 min, 170°C for 0.4 min and 160°C for 0.4 min, to form a first passivation layer on the surface of the aluminum layer and a second passivation layer on the surface of the nickel layer.

[0226] 4) Preparation of polypropylene layer:

[0227] The maleic anhydride modified polypropylene material in the adhesive layer uses QF551 brand particles, the polypropylene material in the first polypropylene sublayer uses PC480A brand particles, and the polypropylene material in the second polypropylene sublayer uses FL7632 brand particles (C0SMOPLENE company). The polypropylene layer is prepared by cast co-extrusion.

[0228] 5) Preparation of aluminum-plastic film:

[0229] The second adhesive polyurethane glue (weight average molecular weight of 25,000) is coated on the surface of the polycaprolactam layer (i.e. nylon layer, thickness of 15 μm) at a coating speed of 15 m / min and a coating amount of 5 g / m 2 , then baked at 65°C for 0.4 min, 75°C for 0.4 min, and 60°C for 0.4 min, and then laminated with a polyethylene terephthalate layer (4.5 μm thick) at a laminating temperature of 30°C and a laminating speed of 15 m / min to obtain a first composite layer, the first composite layer comprising a polyethylene terephthalate layer, a second adhesive layer, and a polycaprolactam layer laminated in sequence;

[0230] Laminating the polypropylene layer on the surface of the second passivation layer at a laminating temperature of 200° C. and a laminating speed of 15 m / min to obtain a second composite layer, the second composite layer comprising a first passivation layer, a composite metal layer, a second passivation layer, and a polypropylene layer stacked in sequence;

[0231] The surface of the first passivation layer in the second composite layer is coated with the first adhesive polyurethane glue (weight average molecular weight of 60,000) at a coating speed of 15 m / min and a coating amount of 5 g / m 2, then baked at 65°C for 0.4 min, 75°C for 0.4 min, and 60°C for 0.4 min, and then laminated with the first composite layer at a laminating temperature of 70°C and a laminating speed of 15 m / min; during this process, a first adhesive layer is formed, and the first adhesive layer is located between the polycaprolactam layer and the first passivation layer; finally, after aging at 70°C for 4 days, the aluminum-plastic film of this embodiment is obtained.

[0232] The aluminum-plastic films prepared in the above examples were subjected to the following tests:

[0233] 1) Cut the aluminum-plastic film into 1cm pieces 2 ×1cm 2 The aluminum-plastic film pieces are cut and peeled off by a mechanical peeling method to obtain a composite metal layer; the peeled composite metal layer is then cleaned to remove impurities (such as adhesive) remaining on the surface to avoid affecting the test results; finally, the nickel layer in the cleaned composite metal layer is tested by scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) to obtain the mass content of phosphorus, the mass content of tungsten, and the mass content of nickel in the nickel layer. It is calculated that the mass content ratio of phosphorus to nickel in the nickel layer is 7%, and the mass content ratio of tungsten to nickel in the nickel layer is 1%;

[0234] The composite metal layer obtained by the above peeling was subjected to metallographic sectioning and tested with an ultra-depth-of-field microscope and image analysis software ImageJ. It was found that the thickness of the nickel layer in the composite metal layer was 0.6 μm, the thickness of the copper layer was 2.4 μm, and the thickness of the aluminum layer was 55 μm. The total thickness of the composite metal layer was 58 μm.

[0235] 2) Cut the aluminum-plastic film into 1cm pieces 2 ×1cm 2 A small piece of aluminum-plastic film was prepared, and the first passivation layer and the second passivation layer in the small piece of aluminum-plastic film were separated to obtain the first passivation layer sample and the second passivation layer sample respectively; the first passivation layer sample and the second passivation layer sample were tested with reference to ISO 17294: "Determination of element content in materials by inductively coupled plasma atomic emission spectrometry (ICP-OES)", and the content of chromium in the first passivation layer and the content of chromium in the second passivation layer were calculated according to the formula (c×V) / S, and the unit was mg / m 2 Wherein, c refers to the mass concentration of chromium in the test solution, V refers to the volume of the test solution, and S refers to the area of the passivation layer sample. The above test results show that the content of chromium in the first passivation layer is 5 mg / m 2 The chromium content in the second passivation layer is 15 mg / m 2 .

[0236] 3) separating the adhesive layer, the first polypropylene sublayer, and the second polypropylene sublayer from the aluminum-plastic film as samples to be tested;

[0237] The adhesive layer sample was tested in accordance with ISO 16014-1: "Polymer-modified materials - Characterization of maleic anhydride-grafted polyolefins," and the grafting rate of maleic anhydride in the maleic anhydride-modified polypropylene material was found to be 2.5%.

[0238] According to ASTM D3418: Standard Test Method (DSC Determination of Polymer Melting Temperature), the adhesive layer sample, the first polypropylene sublayer sample, and the second polypropylene sublayer sample were tested, respectively. The melting points of the adhesive layer, the first polypropylene layer, and the second polypropylene layer were 147°C, 165°C, and 139°C, respectively.

[0239] Referring to ASTM D1238: "Standard Test Method: Melt Flow Rate of Plastics", the test samples of the adhesive layer, the test samples of the first polypropylene layer, and the test samples of the second polypropylene layer were tested respectively. The melt index of the adhesive layer was 4.4 g / 10 min, the melt index of the first polypropylene layer was 2 g / 10 min, and the melt index of the second polypropylene layer was 7 g / 10 min.

[0240] 5) Referring to ISO 3034: "Plastic films — Determination of thickness," the aluminum-plastic film was measured, and the thickness of the adhesive layer was 8 μm, the thickness of the first polypropylene sublayer was 64 μm, the thickness of the second polypropylene sublayer was 8 μm, and the thickness of the polypropylene layer was 80 μm; the thickness of the nylon layer was 15 μm, and the thickness of the polyethylene terephthalate layer was 4.5 μm; the thickness of the second adhesive layer was 3 μm, and the thickness of the first adhesive layer was 3 μm.

[0241] 6) Separate the first adhesive layer and the second adhesive layer from the aluminum-plastic film as test samples; refer to ISO 14704: "Packaging - Determination of Net Content" weighing method, test the above test samples respectively, and obtain the surface density of the first adhesive layer is 4g / m 2 The surface density of the second adhesive layer is 4g / m 2 .

[0242] Example 2

[0243] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that, through the preparation process of the copper-aluminum composite layer, the thickness of the aluminum layer before rolling is reduced to 75 μm, the pretreated raw material is fed into the cold rolling unit, and the deformation of the raw material after the first cold rolling is controlled to 70%. After four consecutive cold rolling processes, the designed thickness of 17.4 μm is reached; after testing, the thickness of the aluminum layer is 15 μm, and the rest remains unchanged.

[0244] Example 3

[0245] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that, in the preparation process of the copper-aluminum composite layer, the thickness of the aluminum layer before rolling is reduced to 135 μm, the pretreated raw material is fed into the cold rolling unit, and the deformation of the raw material after the first cold rolling is controlled to 70%. After four consecutive cold rolling processes, the designed thickness of 29.4 μm is reached; after testing, the thickness of the aluminum layer is 27 μm, and the rest remains unchanged.

[0246] Example 4

[0247] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that, in the preparation process of the copper-aluminum composite layer, the thickness of the aluminum layer before rolling is reduced to 325 μm, the pretreated raw material is fed into the cold rolling unit, and the deformation of the raw material after the first cold rolling is controlled to 70%. After four consecutive cold rolling processes, the designed thickness of 67.4 μm is reached; after testing, the thickness of the aluminum layer is 65 μm, and the rest remains unchanged.

[0248] Example 5

[0249] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that, in the preparation process of the copper-aluminum composite layer, the thickness of the aluminum layer before rolling is reduced to 350 μm, the pretreated raw material is fed into the cold rolling unit, and the deformation of the raw material after the first cold rolling is controlled to 70%. After four consecutive cold rolling processes, the designed thickness reaches 72.4 μm; after testing, the thickness of the aluminum layer is 70 μm, and the rest remains unchanged.

[0250] Example 6

[0251] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that, in the preparation process of the copper-aluminum composite layer, the thickness of the copper layer before rolling is reduced to 5 μm, the pretreated raw material is fed into the cold rolling unit, and the deformation of the raw material after the first cold rolling is controlled to 70%. After four consecutive cold rolling processes, the designed thickness of 56 μm is reached; after testing, the thickness of the copper layer is 1 μm, and the rest remains unchanged.

[0252] Example 7

[0253] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0254] During the preparation process of the copper-aluminum composite layer, the thickness of the copper layer before rolling was reduced to 10 μm. The pretreated raw materials were fed into the cold rolling mill. The deformation of the raw materials after the first cold rolling was controlled at 70%. After four consecutive cold rolling processes, the designed thickness reached 57 μm. After testing, the thickness of the copper layer was 2 μm, and the rest remained unchanged.

[0255] Example 8

[0256] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0257] During the preparation process of the copper-aluminum composite layer, the thickness of the copper layer before rolling was reduced to 15μm. The pretreated raw materials were sent to the cold rolling unit. The deformation of the raw materials after the first cold rolling was controlled to 70%. After four consecutive cold rolling processes, the designed thickness of 58μm was reached. After testing, the thickness of the copper layer was 3μm, and the rest remained unchanged.

[0258] Example 9

[0259] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0260] During the preparation process of the copper-aluminum composite layer, the thickness of the copper layer before rolling was reduced to 20 μm. The pretreated raw materials were fed into the cold rolling mill. The deformation of the raw materials after the first cold rolling was controlled at 70%. After four consecutive cold rolling processes, the designed thickness reached 59 μm. After testing, the thickness of the copper layer was 4 μm, and the rest remained unchanged.

[0261] Example 10

[0262] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0263] During the nickel plating process on the composite metal layer, the current density is controlled to be 10A / dm 2 ; After testing, the thickness of the nickel layer on the surface of the prepared composite metal layer is 0.5μm.

[0264] Example 11

[0265] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0266] During the nickel plating process on the composite metal layer, the current density is controlled to be 60A / dm 2 ; After testing, the thickness of the nickel layer on the surface of the prepared composite metal layer is 1μm.

[0267] Example 12

[0268] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0269] During the nickel plating process on the composite metal layer, the current density is controlled to 70A / dm 2 ; After testing, the thickness of the nickel layer on the surface of the prepared composite metal layer is 1.5μm.

[0270] Example 13

[0271] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0272] During the nickel plating process on the surface of the composite metal layer, the mass concentration of the nickel-phosphorus additive in the electroplating solution was controlled to 1 mol / L; after testing, the mass content ratio of phosphorus to nickel in the nickel layer was 5%, that is, A / C = 5%.

[0273] Example 14

[0274] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0275] During the nickel plating process on the surface of the composite metal layer, the mass concentration of the nickel-phosphorus additive in the electroplating solution was controlled to be changed to 1.5 mol / L; after testing, the mass content ratio of phosphorus to nickel in the nickel layer was 6%, that is, A / C = 6%.

[0276] Example 15

[0277] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0278] During the nickel plating process on the surface of the composite metal layer, the mass concentration of the nickel-phosphorus additive in the electroplating solution was controlled to be changed to 3.5 mol / L; after testing, the mass content ratio of phosphorus to nickel in the nickel layer was 8%, that is, A / C = 8%.

[0279] Example 16

[0280] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0281] During the nickel plating process on the surface of the composite metal layer, the mass concentration of the nickel-phosphorus additive in the electroplating solution was controlled to 4 mol / L; after testing, the mass content ratio of phosphorus to nickel in the nickel layer was 9%, that is, A / C = 9%.

[0282] Example 17

[0283] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0284] During the nickel plating process on the surface of the composite metal layer, the sodium tungstate content in the electroplating solution is controlled to be 0%, i.e., no sodium tungstate is added; after testing, the mass content ratio of tungsten element to nickel element in the nickel layer is 0%, i.e., B / C = 0%.

[0285] Example 18

[0286] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0287] During the nickel plating process on the surface of the composite metal layer, the sodium tungstate content in the electroplating solution was controlled to be 0.5%. After testing, the mass content ratio of tungsten element to nickel element in the nickel layer was 0.1%, that is, B / C = 0.1%.

[0288] Example 19

[0289] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0290] During the nickel plating process on the surface of the composite metal layer, the sodium tungstate content in the electroplating solution was controlled to be 1%. After testing, the mass content ratio of tungsten element to nickel element in the nickel layer was 0.5%, that is, B / C = 0.5%.

[0291] Example 20

[0292] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that:

[0293] During the nickel plating process on the surface of the composite metal layer, the sodium tungstate content in the electroplating solution was controlled to be 2.5%. After testing, the mass content ratio of tungsten element to nickel element in the nickel layer was 1.5%, that is, B / C = 1.5%.

[0294] Comparative Example 1

[0295] The preparation method of the aluminum-plastic film in this comparative example is basically the same as that in Example 1, except that the composite metal layer is replaced by an aluminum layer with a thickness of 60 μm.

[0296] Comparative Example 2

[0297] The preparation method of the aluminum-plastic film in this comparative example is basically the same as that in Example 1, except that:

[0298] The copper-aluminum composite layer is directly passivated during preparation without going through a nickel electroplating process, that is, the nickel layer thickness on the surface of the prepared composite metal layer is 0 μm, and then the aluminum-plastic film is prepared.

[0299] Test example

[0300] 1. The anti-corrosion performance of the aluminum-plastic films prepared in the above examples and comparative examples was tested:

[0301] A 75 mm × 48 mm mold was used to prepare the aluminum-plastic film prepared in the above embodiments and comparative examples into an aluminum-plastic film shell, with the side surface having the polypropylene layer serving as the inner surface of the aluminum-plastic film bag. A small soft-pack battery was simply prepared in the laboratory, with the negative electrode ear in the soft-pack battery overlapping the composite metal layer in the aluminum-plastic film. The batteries were placed in a 45°C environment and stored for 7 days, 21 days, and 28 days, respectively, to observe whether corrosion and leakage occurred. Each embodiment and comparative example was tested in a group of 5 batteries, and the number of batteries in each group that corroded after storage was recorded. For example, if 3 out of 5 batteries corroded, it was recorded as 3 / 5 PASS. The test results are shown in Table 1.

[0302] Table 1

[0303]

[0304]

[0305] 2. The electrolyte resistance of the aluminum-plastic films prepared in the above examples and comparative examples was tested:

[0306] The aluminum-plastic films prepared in the above examples and comparative examples were immersed in an electrolyte at 85°C for 14 and 28 days, respectively. T-peel tests were then performed at a tensile speed of 45 mm / min. The test method followed the T-peel test, Method 3, in ASTM D429: Test Methods for Peel and Shear Strength of Adhesives. The test results are shown in Table 2.

[0307] Table 2

[0308]

[0309]

[0310] Combining Table 1 and Table 2, we can see that:

[0311] Compared to Comparative Example 1, the aluminum-plastic films in Examples 1-20 all exhibited superior corrosion resistance and electrolyte resistance. The soft-pack battery in Example 1 showed no corrosion or leakage after 28 days of storage at 45°C. Furthermore, the peel force between the polypropylene layer and the composite metal layer remained at a high level of 13.1 N / 15 mm after 28 days of immersion in electrolyte.

[0312] In the aluminum-plastic film in Example 16, the phosphorus content in the nickel layer is too much, and the mass content ratio of phosphorus to nickel in the nickel layer is 9%, which exceeds the preferred range of 6% to 8%; in the aluminum-plastic film in Example 20, the tungsten content in the nickel layer is too much, and the mass content ratio of tungsten to nickel in the nickel layer is 1.5%, which exceeds the preferred range of 0.1% to 1%; both of the above situations will cause the internal structure of the nickel layer to change, thereby affecting the passivation effect, making it impossible for the passivation layer to exist stably on the surface of the copper layer, thereby causing the bonding strength between the composite metal layer and the polypropylene layer to decrease, and having a negative impact on the electrolyte resistance of the aluminum-plastic film.

[0313] However, the soft-pack battery in Comparative Example 1 suffered from corrosion and leakage after being stored for 14 days under the same conditions, and the peeling force between the polypropylene layer and the composite metal layer was reduced to 10.3N / 15mm after being immersed in the electrolyte for 28 days.

[0314] In the soft-pack battery of Comparative Example 2, the composite metal layer in the aluminum-plastic film does not contain a nickel layer. No corrosion or leakage occurs after storage for 28 days under the same conditions. This is due to the presence of a copper layer in the composite metal layer. However, as can be seen from Table 2, the electrolyte resistance of the aluminum-plastic film is significantly reduced. After immersion in the electrolyte for 28 days, the peeling force between the polypropylene layer and the composite metal layer is reduced to 3.0 N / 15 mm, which greatly deteriorates the electrolyte resistance of the aluminum-plastic film. This is mainly because the passivation effect is greatly affected when no nickel layer is present, which has a negative impact on the electrolyte resistance of the aluminum-plastic film.

[0315] From the above analysis, it can be seen that the aluminum-plastic film in the present invention has good electrochemical corrosion resistance and can effectively improve the safety of the battery.

[0316] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An aluminum-plastic film, characterized in that: The aluminum-plastic film comprises a nylon layer, a first passivation layer, a composite metal layer, a second passivation layer, and a polypropylene layer which are stacked in sequence; the composite metal layer comprises an aluminum layer, a copper layer, and a nickel layer which are stacked in sequence.

2. The aluminum-plastic film according to claim 1, characterized in that The thickness of the composite metal layer is 30 μm to 70 μm; preferably, the thickness of the aluminum layer is 27 μm to 65 μm; and / or the thickness of the copper layer is 2 μm to 3 μm; and / or the thickness of the nickel layer is 0.5 μm to 1 μm.

3. The aluminum-plastic film according to claim 1 or 2, characterized in that The nickel layer includes phosphorus and / or tungsten; the nickel layer satisfies: 6%≤A / C≤8%, and / or, 0.1%≤B / C≤1%, Wherein, A is the mass content of phosphorus in the nickel layer, B is the mass content of tungsten in the nickel layer, and C is the mass content of nickel in the nickel layer, and the units of A, B, and C are the same.

4. The aluminum-plastic film according to any one of claims 1 to 3, characterized in that The first passivation layer includes chromium, and the content of the chromium in the first passivation layer is 4 mg / m 2 ~6 mg / m 2 and / or, the second passivation layer includes chromium, the chromium content in the second passivation layer is 15mg / m 2 ~20 mg / m 2 .

5. The aluminum-plastic film according to any one of claims 1 to 4, characterized in that: The nylon layer includes nylon-based materials, and the nylon-based materials include polycaprolactam and / or polyhexamethylene adipamide; preferably, the thickness of the nylon layer is 10 μm to 25 μm.

6. The aluminum-plastic film according to any one of claims 1 to 5, characterized in that: The polypropylene layer includes an adhesive layer and a polypropylene sublayer stacked in sequence, and the adhesive layer is arranged close to the second passivation layer; the adhesive layer includes maleic anhydride modified polypropylene material, and the polypropylene sublayer includes polypropylene material.

7. The aluminum-plastic film according to claim 6, characterized in that: The grafting rate of maleic anhydride in the maleic anhydride modified polypropylene material is 0.5% to 3.5%.

8. The aluminum-plastic film according to claim 6 or 7, characterized in that: The polypropylene sublayer includes a first polypropylene sublayer and a second polypropylene sublayer stacked in sequence, and the first polypropylene sublayer is arranged close to the adhesive layer; preferably, the melting point of the first polypropylene sublayer is 160°C to 170°C, and the melt index is 2g / 10min to 5g / 10min, and the melting point of the second polypropylene sublayer is 135°C to 145°C, and the melt index is 5g / 10min to 10g / 10min.

9. The aluminum-plastic film according to claim 8, characterized in that: The thickness ratio of the adhesive layer, the first polypropylene sublayer and the second polypropylene sublayer is (0.7-1.5):(6-8):(0.5-1.5); preferably, the thickness of the polypropylene layer is 60 μm to 80 μm.

10. The aluminum-plastic film according to any one of claims 1 to 9, characterized in that: The aluminum-plastic film further includes a polyethylene terephthalate layer, and the polyethylene terephthalate layer is arranged on a side of the nylon layer away from the first passivation layer.

11. The aluminum-plastic film according to claim 10, characterized in that: The polyethylene terephthalate layer has a thickness of 1.5 μm to 4.5 μm.

12. The aluminum-plastic film according to any one of claims 1 to 11, characterized in that: The aluminum-plastic film also includes a sealing layer, which is arranged between the composite metal layer and the second passivation layer; the sealing layer includes a silane coupling agent; preferably, the silane coupling agent includes at least one of polyacrylic resin, aminosilane coupling agent, vinylsilane coupling agent, and epoxysilane coupling agent.

13. A method for preparing the aluminum-plastic film according to any one of claims 1 to 12, characterized in that: The following steps are involved: Compounding copper and aluminum to obtain a copper-aluminum composite layer; then performing nickel plating on the surface of the copper layer in the copper-aluminum composite layer to obtain a composite metal layer; A first passivation layer and a nylon layer are sequentially stacked on the aluminum layer side of the composite metal layer, and a second passivation layer and a polypropylene layer are sequentially stacked on the nickel layer side of the composite metal layer to obtain the aluminum-plastic film.

14. The method for preparing an aluminum-plastic film according to claim 13, wherein: The method of compounding the copper material and the aluminum material includes a cold rolling process, and the cold rolling process includes: Copper and aluminum materials are used as raw materials, and the raw materials are pretreated to remove surface oxides and impurities; the pretreated raw materials are sent to a cold rolling unit, and undergo multiple continuous cold rolling processes to gradually reduce the thickness. After reaching the designed thickness, annealing is performed to obtain the copper-aluminum composite layer.

15. The method for preparing an aluminum-plastic film according to claim 14, wherein: After the first cold rolling, the deformation of the raw material is not less than 65%.

16. The method for preparing an aluminum-plastic film according to claim 14 or 15, wherein: The annealing treatment is performed at a temperature of 300° C. to 500° C. and for a time of 2 hours to 8 hours.

17. The method for preparing an aluminum-plastic film according to any one of claims 13 to 16, characterized in that: A polyethylene terephthalate layer is disposed on a side of the nylon layer away from the first passivation layer.

18. A battery, characterized in that: The invention comprises the aluminum-plastic film according to any one of claims 1 to 12, or the aluminum-plastic film prepared by the preparation method according to any one of claims 13 to 17.

19. A battery pack, characterized in that: The invention comprises the aluminum-plastic film according to any one of claims 1 to 12, or the aluminum-plastic film prepared by the preparation method according to any one of claims 13 to 17, or the battery according to claim 18.

20. An electrical device, characterized in that: The invention comprises the aluminum-plastic film according to any one of claims 1 to 12, or the aluminum-plastic film prepared by the preparation method according to any one of claims 13 to 17, or the battery according to claim 18, or the battery pack according to claim 19.

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