Composite plastic film material, preparation method thereof, battery and electric device

Abstract

The application relates to a composite plastic film material and a preparation method thereof, a battery and an electric device, the composite plastic film material comprising a first plastic film layer, a functional film layer and a second plastic film layer which are sequentially stacked; the functional film layer comprises a composite metal layer, components of the composite metal layer comprise nickel elements and iron elements, and the mass proportion K1% of the nickel elements in the composite metal layer satisfies K1% >= 50%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional materials, in particular to a composite plastic film material, a preparation method thereof, a battery and an electric device. BACKGROUND

[0002] In recent years, with the rapid development of the new energy industry, the update speed of electric devices such as electronic products and electric vehicles is getting faster and faster, and people are pursuing the lightweight of electric devices. Therefore, soft package batteries with good safety performance and light weight are attracting attention.

[0003] Most of the traditional soft package batteries are packaged by aluminum plastic films, which mainly consist of a nylon outer layer, an aluminum layer and a polypropylene (PP) inner layer, and are bonded by setting an adhesive layer between each layer. However, the traditional aluminum plastic film has low strength, poor puncture resistance and weak corrosion resistance, which leads to the fact that the batteries are easily damaged during the process conversion after packaging due to the collision and friction between the batteries or the collision and friction between the external objects and the batteries, and the inner layer of the aluminum plastic film is in contact with the electrolyte and is easily corroded by the electrolyte, and the outer layer is in contact with the external environment and is also easily corroded by water, oxygen and the like. When the outer layer or the inner layer of the aluminum plastic film is damaged, the aluminum layer in the middle layer will be exposed, and during the use of the electric device, the exposed aluminum layer in the battery may come into contact with other metal devices to form a primary battery, causing primary battery corrosion reaction, and also bringing the risk of battery swelling and leakage, affecting the safety performance of the electric device.

[0004] Therefore, the traditional technology still needs to be improved. SUMMARY

[0005] Therefore, it is necessary to provide a composite plastic film material, a preparation method thereof, a battery and an electric device, which have excellent penetration resistance and corrosion resistance.

[0006] The present application is realized by the following technical solutions.

[0007] In a first aspect of the present application, a composite plastic film material is provided, which comprises a first plastic film layer, a functional film layer and a second plastic film layer which are sequentially stacked.

[0008] The functional film layer comprises a composite metal layer, the components of the composite metal layer comprise nickel and iron elements, and the mass percentage K1% of the nickel element in the composite metal layer satisfies: K1%≥50%.

[0009] The composite plastic film material comprises a first plastic film layer, a functional film layer and a second plastic film layer arranged in sequence, the components of the composite metal layer in the functional film layer include nickel elements and iron elements, the nickel elements and the iron elements cooperate to have good corrosion resistance to water and oxygen-based electrolyte, the mass percentage K1% of the nickel elements in the composite metal layer is controlled to be greater than or equal to 50%, the mechanical strength of the functional film layer is improved while the excellent corrosion resistance is maintained, and the composite plastic film material has excellent penetration resistance and corrosion resistance.

[0010] In some embodiments, K1% satisfies: 50%≤K1%≤90%;

[0011] Optionally, K1% satisfies: 65%≤K1%≤85%.

[0012] Further regulating the mass percentage K1% of the nickel elements in the composite metal layer further improves the penetration resistance and corrosion resistance of the composite plastic film material.

[0013] In some embodiments, the mass percentage K2% of the iron elements in the composite metal layer satisfies: K2%≥10%;

[0014] Optionally, the mass percentage K2% of the iron elements in the composite metal layer satisfies: 10%≤K2%≤50%.

[0015] Further regulating the mass percentage K2% of the iron elements in the composite metal layer further improves the penetration resistance and corrosion resistance of the composite plastic film material.

[0016] In some embodiments, the mass percentage K1% of the nickel elements in the composite metal layer and the mass percentage K2% of the iron elements in the composite metal layer satisfy: K1%+K2%≥98%.

[0017] In some embodiments, the composite metal layer satisfies at least one of the following (1)-(3):

[0018] (1) the thickness of the composite metal layer is 20-40 μm;

[0019] Optionally, the thickness of the composite metal layer is 25-35 μm;

[0020] (2) the surface roughness of at least one surface of the composite metal layer is 0.8-3.2 μm;

[0021] the surface roughness of at least one surface of the composite metal layer is 1.6-3.2 μm;

[0022] By regulating the roughness of the surface of the composite metal layer, the adhesion between the composite metal layer and other layers can be improved, thereby improving the bonding performance of the composite plastic film material, and when applied to the preparation of a battery, the service life and safety performance of the battery can be further improved.

[0023] (3) The tensile strength of the composite metal layer is 600 Mpa-910 Mpa.

[0024] In some embodiments, the functional film layer satisfies at least one of the following (4)-(5):

[0025] (4) The functional film layer further comprises a first corrosion-resistant metal layer arranged on the side of the composite metal layer close to the first plastic film layer;

[0026] Optionally, the thickness of the first corrosion-resistant metal layer is 1-5 μm;

[0027] Optionally, the metal in the first corrosion-resistant metal layer comprises at least one of Al, Cr and Ni;

[0028] (5) The functional film layer further comprises a second corrosion-resistant metal layer arranged on the side of the composite metal layer close to the second plastic film layer;

[0029] Optionally, the thickness of the second corrosion-resistant metal layer is 1-5 μm;

[0030] Optionally, the metal in the second corrosion-resistant metal layer comprises at least one of Al, Cr and Ni.

[0031] By arranging the first corrosion-resistant metal layer and the second corrosion-resistant metal layer, the corrosion resistance of the composite plastic film material is further improved while the excellent mechanical strength is maintained.

[0032] In some embodiments, the thickness of the functional film layer is 20-40 μm;

[0033] Optionally, the thickness of the functional film layer is 25-40 μm;

[0034] Optionally, the thickness of the functional film layer is 25-35 μm.

[0035] Further adjusting the thickness of the functional film layer as a whole further improves the mechanical strength of the composite plastic film material.

[0036] In some embodiments, the mass fraction of the nickel element in at least one surface layer of the composite metal layer is H1, the mass fraction of the nickel element in any layer between the two surface layers of the composite metal layer is H2, and H1 and H2 satisfy: H1>H2;

[0037] Optionally, the mass percentage of the nickel element in each of the two surface layers of the composite metal layer is selected from H1;

[0038] Optionally, the thickness of the surface layer is 1-5 μm.

[0039] Optionally, H1 satisfies 75%≤H1≤100%.

[0040] The distribution of the nickel element in the composite metal layer is regulated, so that the mass percentage of the nickel element in at least one surface layer is greater than that in the layer between the two surface layers, thereby further improving the corrosion resistance of the composite metal layer while ensuring the strength.

[0041] In some embodiments, the layer at the level of the horizontal line at the half thickness of the composite metal layer is the center layer, and in the direction in which the center layer extends vertically to at least one surface layer of the composite metal layer, the mass percentage of the distributed nickel element shows an increasing trend.

[0042] Optionally, in the direction in which the center layer extends vertically to each of the two surface layers of the composite metal layer, the mass percentage of the nickel element shows an increasing trend.

[0043] Optionally, the thickness of the center layer is 2-10 μm.

[0044] The distribution of the nickel element in the composite metal layer is regulated, so that in the direction in which the center layer extends to the surface layer, the mass percentage of the distributed nickel element shows an increasing trend, in other words, the closer to the surface layer, the higher the mass percentage of the nickel element.

[0045] In some embodiments, in the composite metal layer, the mass percentage of the distributed nickel element in the layers on both sides of the center layer shows a symmetrical relationship with the center layer as the symmetrical axis.

[0046] In other words, the mass percentage of the distributed nickel element in the layers on both sides of the center layer increases in the same law.

[0047] Optionally, the thickness of the composite metal layer is D μm, the mass percentage of the nickel element in any layer between the surface layer and the center layer in the composite metal layer is Y, the vertical distance from any layer between the surface layer and the center layer in the composite metal layer to the center layer is R, and H=2R / D.

[0048] Y and the mass percentage K1% of the nickel element in the composite metal layer satisfy the following relationship:

[0049] Y=(2-2K1%)×H+2K1%-1, (2K1%-1)≤y≤1.

[0050] Further, the present inventors summarize the relationship formula of the mass percentage of nickel Y in any one layer between the surface layer and the center layer in the composite metal layer through a large number of experiments, so as to control the mass percentage of nickel in the layers on both sides of the center layer to increase in the same specific law.

[0051] In some embodiments, the second plastic film layer satisfies at least one of the following (6) and (7):

[0052] (6) The thickness of the second plastic film layer is 30 μm to 50 μm;

[0053] (7) The component of the second plastic film layer comprises polypropylene.

[0054] In some embodiments, the component of the first plastic film layer comprises at least one of a nylon material and polyethylene terephthalate;

[0055] Optionally, the first plastic film layer comprises at least one of a nylon material layer and a polyethylene terephthalate layer;

[0056] Optionally, the first plastic film layer comprises a nylon material layer and a polyethylene terephthalate layer which are stacked in sequence, and the nylon material layer is closer to the functional film layer than the polyethylene terephthalate layer.

[0057] In some embodiments, the thickness of the nylon material layer is 20 μm to 30 μm, and the thickness of the polyethylene terephthalate layer is 5 μm to 20 μm.

[0058] In some embodiments, an adhesive layer is further provided between each layer;

[0059] Optionally, the thickness of each adhesive layer is independently selected from 1 μm to 5 μm; optionally, 1 μm to 2 μm;

[0060] Optionally, the adhesive component of the adhesive layer comprises at least one of a polyolefin resin, an epoxy resin, a polyurethane, a polyester polyol, and a polyisocyanate.

[0061] In a second aspect, the present application provides a preparation method of the composite plastic film material of the first aspect, characterized in that the preparation method comprises the following preparation steps of the composite metal layer:

[0062] Providing an anode material and a cathode material; the anode material comprises nickel elements and iron elements, and the cathode material is a titanium alloy;

[0063] Placing the anode material and the cathode material in an electroplating solution for electroplating treatment, depositing nickel elements and iron elements on the surface of the cathode material to form the composite metal layer;

[0064] wherein the components of the electroplating solution include a nickel salt, an iron salt, and water;

[0065] or, a preparation step of the composite metal layer as described below:

[0066] a target material is used for physical vapor deposition to prepare the composite metal layer; the components of the target material include nickel element and iron element.

[0067] In some embodiments, the electroplating process satisfies at least one of the following (8)~(10):

[0068] (8) the current of the electroplating process is 9.5 A / cm 2 ~10.8 A / cm 2 ;

[0069] (9) the temperature of the electroplating process is 45℃~60℃;

[0070] (10) the speed of the electroplating process is 1.0 m / min~1.6 m / min.

[0071] By adjusting the process conditions of the electroplating process, the thickness of the composite metal layer formed can be adjusted.

[0072] In some embodiments, the electroplating solution satisfies at least one of the following (11)~(13):

[0073] (11) the pH value of the electroplating solution is 2~3.5;

[0074] (12) in the electroplating solution, the concentration of the nickel salt is 100 g / L ~150 g / L, and the concentration of the iron salt is 25 g / L ~75 g / L;

[0075] Optionally, the nickel salt includes a water-soluble nickel salt;

[0076] Optionally, the nickel salt includes at least one of NiSO4 and NiCl2;

[0077] Optionally, the iron salt includes a water-soluble iron salt;

[0078] Optionally, the iron salt includes FeSO4;

[0079] (13) the components of the electroplating solution further include a surfactant;

[0080] Optionally, the concentration of the surfactant is 1 g / L ~2.5 g / L;

[0081] Optionally, the surfactant includes an anionic surfactant;

[0082] Optionally, the surfactant includes at least one of sodium dodecyl sulfonate and sodium dodecyl sulfate.

[0083] By regulating the components and their concentrations of the electroplating solution, the mass ratio of the middle element of the composite metal layer, the surface roughness, etc. can be adjusted.

[0084] In a third aspect, the application provides a battery comprising the composite plastic film material of the first aspect.

[0085] The composite plastic film material has excellent penetration resistance and corrosion resistance, and can improve the service life and safety performance of the battery.

[0086] In a fourth aspect, the application provides an electrical device comprising the battery of the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0087] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not intended to limit the scope of the application. Moreover, the same reference numerals in different drawings represent the same or similar elements. In the drawings:

[0088] Figure 1 is a structure schematic diagram of the composite plastic film material of an embodiment;

[0089] Figure 2 is a structure schematic diagram of the composite plastic film material of another embodiment;

[0090] Figure 3 is a structure schematic diagram of the composite plastic film material of still another embodiment.

[0091] BRIEF DESCRIPTION OF DRAWINGS

[0092] 10, composite plastic film material; 11, first plastic film layer; 111, nylon material layer, 112, polyethylene terephthalate layer; 12, functional film layer; 121, composite metal layer; 122, first corrosion-resistant metal layer; 123, second corrosion-resistant metal layer; 13, second plastic film layer; 14, adhesive layer. DETAILED DESCRIPTION

[0093] In order to make the above objectives, features and advantages of the application more apparent, the specific embodiments of the application are described in detail below. In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the application. However, the application can be implemented in many different ways other than those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the application, so the application is not limited to the specific embodiments disclosed below.

[0094] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0095] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0096] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0097] In view of the above background, the conventional aluminum-plastic film has low strength, poor puncture resistance, easy deformation and poor corrosion resistance. Technical personnel have been committed to exploring new plastic film materials, but so far there has been no special breakthrough and progress to replace the traditional aluminum-plastic film.

[0098] To solve this problem, the present inventors found in the long-term actual production and research and development process that the alloy of iron and nickel has good corrosion resistance, and further adjusting the mass percentage of nickel element can improve the mechanical strength of the plastic film material. After a lot of creative exploration, the present application obtains a composite plastic film material with excellent penetration resistance and corrosion resistance.

[0099] In an embodiment of the present application, a composite plastic film material is provided, which includes a first plastic film layer, a functional film layer and a second plastic film layer which are sequentially stacked.

[0100] The functional film layer includes a composite metal layer, and the components of the composite metal layer include nickel element and iron element, and the mass percentage K1% of the nickel element in the composite metal layer satisfies: K1%≥50%.

[0101] The composite plastic film material comprises a first plastic film layer, a functional film layer and a second plastic film layer which are sequentially stacked, the components of the composite metal layer in the functional film layer comprise nickel elements and iron elements, the nickel elements and the iron elements cooperate to have good corrosion resistance to water and oxygen-based electrolyte, and the mass percentage K1% of the nickel elements in the composite metal layer is controlled to be greater than or equal to 50%, so that the mechanical strength of the functional film layer is improved while the excellent corrosion resistance is maintained, and the composite plastic film material has excellent penetration resistance and corrosion resistance.

[0102] For details, please refer to Figure 1 In an embodiment of the present application, a composite plastic film material 10 is provided, which comprises a first plastic film layer 11, a functional film layer 12 and a second plastic film layer 13 which are sequentially stacked, the functional film layer 12 comprises a composite metal layer 121, Figure 1 The number 12 is not marked.

[0103] In some embodiments, K1% satisfies: 50%≤K1%≤90%.

[0104] Optionally, K1% satisfies: 65%≤K1%≤85%.

[0105] Further regulating the mass percentage K1% of the nickel elements in the composite metal layer further improves the penetration resistance and corrosion resistance of the composite plastic film material.

[0106] In the above “50%≤K1%≤90%”, the value of ≤K1% includes the minimum value and the maximum value of the range, and every value between the minimum value and the maximum value, specific examples include but are not limited to the following point values in the embodiments: 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%; or a range composed of any two numerical values, for example, it can be 50%~85%, 50%~80%, 50%~75%, 50%~70%, 50%~65%, 50%~60%, 55%~90%, 55%~85%, 55%~80%, 55%~75%, 55%~70%, 55%~65%, 55%~60%, 65%~90%, 65%~85%, 65%~80%, 65%~75%, 65%~70%, 70%~90%, 70%~85%, 70%~80%, 70%~75%, 75%~90%, 75%~85%.

[0107] In some embodiments, the mass percentage K2% of the iron element in the composite metal layer satisfies: K2%≥10%;

[0108] Optionally, the mass percentage K2% of the iron element in the composite metal layer satisfies: 10%≤K2%≤50%.

[0109] Further regulating the mass percentage K2% of the iron element in the composite metal layer further improves the penetration resistance and corrosion resistance of the composite plastic film material.

[0110] In the above "10%≤K2%≤50%", the value of K2% includes the minimum value and the maximum value of the range, and every value between the minimum value and the maximum value, specific examples include but are not limited to the point values in the embodiments and the following point values: 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%; or a range composed of any two numerical values, for example, can be 11%~50%, 15%~50%, 20%~50%, 25%~50%, 30%~50%, 35%~50%, 40%~50%, 45%~50%, 10%~45%, 15%~45%, 20%~45%, 25%~45%, 30%~45%, 35%~45%, 40%~45%, 10%~40%, 15%~40%, 20%~40%, 25%~40%, 30%~40%, 35%~40%, 10%~35%, 15%~35%, 20%~35%, 25%~35%, 30%~35%.

[0111] In some embodiments, the mass percentage K1% of the nickel element in the composite metal layer and the mass percentage K2% of the iron element in the composite metal layer satisfy: K1%+K2%≥98%.

[0112] Optionally, 98%≤K1%+K2%≤100%.

[0113] In some embodiments, the composite metal layer also contains impurity elements.

[0114] The impurity elements are substances introduced during preparation or in the preparation process, including but not limited to: at least one of Cu, Al, Zn and Cr.

[0115] Optionally, 98%≤K1%+K2%<100%.

[0116] In some embodiments, the thickness of the composite metal layer is 20-40 μm.

[0117] Optionally, the thickness of the composite metal layer is 25-43 μm.

[0118] By regulating the thickness of the surface of the composite metal layer, the performance of the composite plastic film is further improved.

[0119] In the above "20-40 μm", the values include the minimum and maximum values of the range, and every value between the minimum and maximum values, specific examples include but are not limited to the following point values in the embodiments: 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, 40 μm; or a range composed of any two numerical values, for example, it can be 21-40 μm, 25-40 μm, 30-40 μm, 35-40 μm, 20-35 μm, 25-35 μm, 30-35 μm, 20-35 μm, 20-30 μm, 25-30 μm.

[0120] In some embodiments, the surface roughness of at least one surface of the composite metal layer is 0.8-6.4 μm.

[0121] Optionally, the surface roughness of the two surfaces of the composite metal layer is independently selected from 0.8-6.4 μm.

[0122] In some embodiments, the surface roughness of at least one surface of the composite metal layer is 1.6-6.4 μm.

[0123] Optionally, the surface roughness of the two surfaces of the composite metal layer is independently selected from 1.6-6.4 μm.

[0124] By regulating the roughness of the surface of the composite metal layer, the adhesion between the composite metal layer and other layers can be improved, thereby improving the bonding performance of the composite plastic film material, and when applied to the preparation of a battery, the service life and safety performance of the battery can be further improved.

[0125] Surface roughness refers to the unevenness of small spacing and small peaks and valleys on the surface. The greater the surface roughness of the surface of the composite metal layer, the greater the frictional resistance between the composite metal layer and other layers, which can prevent slipping, and further regulating the surface roughness can ensure a large frictional resistance with other layers while having good embedding degree with other layers, thereby further improving the adhesion of the composite plastic film material.

[0126] In the above "0.8-3.2 pm", the values include the minimum and maximum values of the range, and every value between the minimum and maximum values, and specific examples include but are not limited to the following point values in the embodiments: 0.8, 1 pm, 2 pm, 3 pm, 3.2 pm; or a range composed of any two numerical values.

[0127] It can be understood that the surface roughness of the two surfaces of the composite metal layer can be the same or different.

[0128] In some embodiments, the tensile strength of the composite metal layer is 600 Mpa-910 Mpa.

[0129] Further, while ensuring that the composite metal layer and other layers have a large frictional resistance, the mechanical strength of the composite metal layer itself is maintained, further improving the mechanical properties of the composite plastic film.

[0130] Specifically, the tensile strength of the composite metal layer is tested as follows: the length and width of the composite metal layer sample are measured with a gauge to 0.05 mm, the sample is symmetrically clamped in the upper and lower clamps of the gauge, the gauge is started and kept at (5±1) mm / min, the maximum load of the composite metal layer sample is recorded, and then the tensile strength σ of the sample is calculated according to the following formula t :

[0131] σ t = p / (b x d)

[0132] Wherein, P is the maximum load (N), b is the sample width (mm), and d is the sample thickness.

[0133] In some embodiments, the functional film layer further comprises a first corrosion-resistant metal layer disposed on the side of the composite metal layer close to the first plastic film layer.

[0134] Optionally, the thickness of the first corrosion-resistant metal layer is 1 pm-5 pm.

[0135] Optionally, the metal in the first corrosion-resistant metal layer includes at least one of Al, Cr and Ni.

[0136] In some embodiments, the functional film layer further comprises a second corrosion-resistant metal layer disposed on the side of the composite metal layer close to the second plastic film layer.

[0137] Optionally, the thickness of the second corrosion-resistant metal layer is 1 pm-5 pm.

[0138] Optionally, the metal in the second corrosion-resistant metal layer includes at least one of Al, Cr and Ni.

[0139] By setting the first corrosion-resistant metal layer and the second corrosion-resistant metal layer, the corrosion resistance of the composite plastic film material is further improved while maintaining excellent mechanical strength, including resistance to electrolyte corrosion.

[0140] It can be understood that when the functional film layer simultaneously has the first corrosion-resistant metal layer and the second corrosion-resistant metal layer, the thickness of the first corrosion-resistant metal layer and the second corrosion-resistant metal layer can be the same or different, and is independently selected from 1 μm to 5 μm.

[0141] In some embodiments, the thickness of the first corrosion-resistant metal layer and the second corrosion-resistant metal layer is the same.

[0142] In the above "1 μm to 5 μm", the values include the minimum and maximum values of the range, and every value between the minimum and maximum values, specific examples include but are not limited to the following point values in the embodiments: 1 μm, 2 μm, 3 μm, 4 μm, 5 μm.

[0143] For details, see Figure 2 An embodiment of the present application provides a composite plastic film material 10, which comprises a first plastic film layer 11, a functional film layer 12 and a second plastic film layer 13 stacked in sequence, the functional film layer 12 comprises a composite metal layer 121, the composite metal layer 121 is provided with a first corrosion-resistant metal layer 122 on the side close to the first plastic film layer 11, and the composite metal layer 121 is provided with a second corrosion-resistant metal layer 123 on the side close to the second plastic film layer 13.

[0144] In some embodiments, the thickness of the functional film layer is 20 μm to 40 μm;

[0145] Optionally, the thickness of the functional film layer is 25 μm to 40 μm;

[0146] Optionally, the thickness of the functional film layer is 25 μm to 35 μm.

[0147] In the above-mentioned "20-40pm", the values include the minimum and maximum values of the range, and every value between the minimum and maximum values. Specific examples include, but are not limited to, the following point values in the embodiments: 21pm, 22pm, 23pm, 24pm, 25pm, 26pm, 27pm, 28pm, 29pm, 30pm, 31pm, 32pm, 33pm, 34pm, 35pm, 36pm, 37pm, 38pm, 39pm, 40pm; or a range formed by any two values, for example, 21-40pm, 25-40pm, 30-40pm, 35-40pm, 21-35pm, 25-35pm, 30-35pm, 21-35pm, 21-30pm, 25-30pm.

[0148] In some embodiments, the mass fraction of the nickel element in at least one surface layer of the composite metal layer is H1, the mass fraction of the nickel element in any layer between the two surface layers of the composite metal layer is H2, and H1 and H2 satisfy: H1>H2.

[0149] Optionally, the mass fraction of the nickel element in the two surface layers of the composite metal layer is selected from H1.

[0150] The distribution of the nickel element in the composite metal layer is regulated so that the mass fraction of the nickel element in at least one surface layer is greater than the mass fraction of the nickel element in the layers between the two surface layers, thereby further improving the corrosion resistance of the composite metal layer while ensuring the strength.

[0151] In some embodiments, the thickness of the surface layer is 1-5pm.

[0152] In some embodiments, H1 satisfies: 75%≤H1≤100%.

[0153] In some embodiments, the center layer is a layer at the level of half the thickness of the composite metal layer, and in the direction of vertical extension of the center layer to at least one surface layer of the composite metal layer, the mass fraction of the distributed nickel element shows an increasing trend.

[0154] In other words, the closer to the surface layer, the higher the mass fraction of the nickel element.

[0155] Optionally, in the direction of vertical extension of the center layer to the two surface layers of the composite metal layer, the mass fraction of the nickel element shows an increasing trend.

[0156] Optionally, the thickness of the center layer is 2-10pm.

[0157] The distribution of the nickel element in the composite metal layer is regulated, and in the direction extending from the center layer to the surface layer, the mass percentage of the distributed nickel element shows an increasing trend, in other words, the closer to the surface layer, the higher the mass percentage of the nickel element.

[0158] In some embodiments, the mass percentage of the nickel distributed in the layers on both sides of the center layer of the composite metal layer is in a symmetrical relationship with the center layer as the axis of symmetry.

[0159] In other words, the mass percentage of the nickel distributed in the layers on both sides of the center layer increases in the same law, that is, the mass percentage of the nickel in the layers with the same perpendicular distance from the center layer is the same.

[0160] Optionally, the thickness of the composite metal layer is D μm, the mass percentage of the nickel in any layer between the surface layer and the center layer of the composite metal layer is Y, the perpendicular distance from any layer between the surface layer and the intermediate layer of the composite metal layer to the center layer is R, and H = 2R / D.

[0161] Y and the mass percentage K1% of the nickel element in the composite metal layer satisfy the following relationship:

[0162] Y = (2-2K1%) x H + 2K1%-1, (2K1%-1) ≤ y ≤ 1.

[0163] Further, the inventors of the present application have summarized through a large number of experiments that the relationship formula of the mass percentage Y of the nickel in any layer between the surface layer and the center layer of the composite metal layer is used to control the mass percentage of the nickel distributed in the layers on both sides of the center layer to increase in the same specific law.

[0164] Specifically, the mass percentage of the nickel element in the two surface layers of the composite metal layer is 100%, and the above formula can be understood as: taking the ratio of 2 times of the perpendicular distance R from any layer between the surface layer and the intermediate layer of the composite metal layer to the center layer and half of the thickness of the composite metal layer as the abscissa, and the corresponding nickel content y as the ordinate, the three scattered point values of the surface layer nickel content and the center layer nickel content are plotted, and the corresponding relationship line Y = aR + b is obtained after correction, and then the slope a and b value of the line are calculated to obtain the above formula.

[0165] In some embodiments, the thickness of the second plastic film layer is 30 μm to 50 μm.

[0166] In some embodiments, the components of the second plastic film layer include polypropylene.

[0167] When applied to the preparation of a battery, the second plastic film layer directly contacts the electrolyte, and the main component of the traditional electrolyte is carbonate. The sealing performance of polypropylene is good and is not easy to be penetrated by the electrolyte.

[0168] The polypropylene can be any polypropylene commonly used in the art, including but not limited to, cast polypropylene.

[0169] In some embodiments, the first plastic film layer comprises at least one of a nylon material and a polyethylene terephthalate.

[0170] Optionally, the first plastic film layer comprises at least one of a nylon material layer and a polyethylene terephthalate layer.

[0171] Optionally, the first plastic film layer comprises a nylon material layer and a polyethylene terephthalate layer stacked in sequence, and the nylon material layer is closer to the functional film layer than the polyethylene terephthalate layer.

[0172] For details, see Figure 3 In an embodiment, the composite plastic film material 10 comprises a first plastic film layer 11, a functional film layer 12 and a second plastic film layer 13 stacked in sequence, the functional film layer 12 comprises a composite metal layer 121, the composite metal layer 121 is provided with a first corrosion-resistant metal layer 122 on the side close to the first plastic film layer 11, and is provided with a second corrosion-resistant metal layer 123 on the side close to the second plastic film layer 13, the first plastic film layer 11 comprises a nylon material layer 111 and a polyethylene terephthalate layer 112 stacked in sequence, and the nylon material layer 111 is closer to the functional film layer 12 than the polyethylene terephthalate layer 112.

[0173] In some embodiments, the thickness of the nylon material layer is 20 μm ~ 30 μm, and the thickness of the polyethylene terephthalate layer is 5 μm ~ 20 μm.

[0174] In some embodiments, an adhesive layer is further provided between each layer.

[0175] Optionally, the thickness of the adhesive layer is 1 μm ~ 5 μm; optionally, 1 μm ~ 2 μm.

[0176] It can be understood that when there are multiple adhesive layers, the thickness of each adhesive layer is independently selected from 1 μm ~ 5 μm.

[0177] In some embodiments, an adhesive layer is provided between the first plastic film layer and the functional film layer, and between the functional film layer and the second plastic film layer; further, the first plastic film layer comprises a nylon material layer and a polyethylene terephthalate layer stacked in sequence, and an adhesive layer is provided between the first plastic film layer and the nylon material layer, and between the nylon material layer and the polyethylene terephthalate layer.

[0178] Further, when the functional film layer further comprises a corrosion-resistant metal layer, the composite metal layer and the corrosion-resistant metal layer can be connected by an adhesive layer or can be directly connected and in contact, for example, the corrosion-resistant metal layer is deposited directly on the surface of the composite metal layer.

[0179] Optionally, the adhesive component of the adhesive layer comprises at least one of a polyolefin resin, an epoxy resin, a polyurethane, a polyester polyol, and a polyisocyanate.

[0180] It can be understood that the adhesive layer is formed by an adhesive, and the adhesive can be commonly used in the art, including but not limited to at least one of a polyolefin resin adhesive, an epoxy resin adhesive, a polyurethane adhesive, a polyester polyol adhesive, and a polyisocyanate adhesive.

[0181] In an embodiment of the present application, a preparation method of the composite plastic film material is provided, comprising the following steps S10-S20 of preparing the composite metal layer:

[0182] Step S10: providing an anode material and a cathode material; the anode material comprises nickel elements and iron elements, and the cathode material is a titanium alloy;

[0183] The anode material and the cathode material are placed in an electroplating solution for electroplating treatment, and the nickel elements and the iron elements are deposited on the surface of the cathode material to form a composite metal layer.

[0184] In some embodiments, the electroplating solution comprises a nickel salt, an iron salt, and water.

[0185] In some embodiments, the current of the electroplating treatment is 9.5 A / cm 2 ~10.8 A / cm 2 .

[0186] In some embodiments, the current of the electroplating treatment is 9.8 A / cm 2 .

[0187] In some embodiments, the temperature of the electroplating treatment is 45°C-60°C.

[0188] In some embodiments, the temperature of the electroplating treatment is 55°C.

[0189] In some embodiments, the speed of the electroplating treatment is 1.0 m / min-1.6 m / min.

[0190] By adjusting the process conditions of the electroplating treatment, the thickness of the composite metal layer formed can be adjusted.

[0191] In some embodiments, the pH value of the electroplating solution is 2-3.5.

[0192] In some embodiments, the concentration of the nickel salt in the electroplating solution is 100 g / L to 150 g / L, and the concentration of the iron salt in the electroplating solution is 25 g / L to 75 g / L.

[0193] In some embodiments, the concentration of the nickel salt in the electroplating solution is 125 g / L, and the concentration of the iron salt in the electroplating solution is 50 g / L.

[0194] In some embodiments, the nickel salt comprises a water-soluble nickel salt.

[0195] Optionally, the nickel salt comprises at least one of NiSO4 and NiCl2.

[0196] In some embodiments, the iron salt comprises a water-soluble iron salt.

[0197] Optionally, the iron salt comprises FeSO4.

[0198] In some embodiments, the components of the electroplating solution further comprise a surfactant.

[0199] In some embodiments, the concentration of the surfactant is 1 g / L to 2.5 g / L.

[0200] In some embodiments, the surfactant comprises an anionic surfactant.

[0201] Optionally, the surfactant comprises at least one of sodium dodecyl sulfonate and sodium dodecyl sulfate.

[0202] By adjusting the components of the electroplating solution and the concentrations thereof, the mass ratio of the elements in the composite metal layer, the surface roughness, etc. can be adjusted, for example, the surface roughness can be adjusted by adjusting the concentration of the acid.

[0203] Specifically, in the electroplating process, it takes a certain time to accumulate the deposition to obtain a composite metal layer of a certain thickness, and the etching degree of the electroplating solution on the two surfaces of the prepared composite metal layer is different. Under the combined action of various factors, the surface roughness of the two surfaces of the composite metal layer can be the same or different.

[0204] Alternatively, the preparation method S30 of the composite metal layer comprises the following steps:

[0205] In step S30, the target material is used for physical vapor deposition treatment to prepare the composite metal layer; the components of the target material comprise nickel elements and iron elements.

[0206] The physical vapor deposition treatment comprises any one of magnetron sputtering and vacuum evaporation; optionally, by adjusting the composition ratio of the target material, the deposition time, and other process conditions, the mass ratio of the elements in the composite metal layer, the surface roughness, and the thickness, etc. can be adjusted.

[0207] An embodiment of the present application provides a battery, which comprises the composite plastic film material of the first aspect.

[0208] The composite plastic film material has excellent penetration resistance and corrosion resistance, and can improve the service life and safety performance of the battery.

[0209] The battery further comprises an electrode assembly, an electrolyte, and the electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator; further, in the composite plastic film material, the second plastic film layer is closer to the electrolyte than the first plastic film layer.

[0210] Further, the composite plastic film material forms a sealed cavity, and the electrode assembly and the electrolyte are placed in the cavity formed by the composite plastic film material.

[0211] It can be understood that the electrode assembly and the electrolyte can use the electrode assembly and the electrolyte commonly used in the art, and here the positive electrode sheet, the negative electrode sheet, the separator and the electrolyte are briefly introduced, including but not limited to the scope introduced as follows.

[0212]

Positive electrode sheet

[0213] The positive electrode sheet comprises a current collector and a positive active layer provided on the surface of the current collector, and the components of the positive active layer comprise a positive active material.

[0214] As an example, the current collector in the positive electrode sheet has two opposite surfaces in the thickness direction of itself, and the positive active material layer is provided on any one or both of the two opposite surfaces of the positive current collector.

[0215] In some embodiments, in the "positive active layer provided on the surface of the current collector", the positive active layer can be provided on at least part of the surface of the current collector, including but not limited to: provided on at least one surface of the current collector and provided on both surfaces of the current collector.

[0216] In some embodiments, the current collector in the positive electrode sheet can use a metal foil or a composite current collector. For example, as a metal foil, an aluminum foil can be used. The composite current collector can comprise a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material on a polymer material base material.

[0217] Optionally, the metal material comprises at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

[0218] Optionally, the polymer material base material comprises at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).

[0219] The above positive electrode active material can use a conventional positive electrode active material in the present application, such as a lithium ion positive electrode active material or a sodium ion positive electrode active material.

[0220] Further, as an example, the lithium ion active material can include at least one of a lithium-containing phosphate of an olivine structure, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material can also be used. These positive electrode active materials can be used alone only or in combination of two or more. Among them, examples of the lithium transition metal oxide can include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2), and a modified compound thereof, etc. Examples of the lithium-containing phosphate of the olivine structure can include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (which can also be referred to as LFP)), lithium manganese phosphate (such as LiMnPO4), and lithium manganese iron phosphate.

[0221] In any embodiment of the present application, the molecular formula of the lithium ion active material is LiFe x Mn (1-x) PO4, and x takes any number from 0 to 1.

[0222] It can be understood that when x takes 0, LiFe x Mn (1-x) PO4 is LiMnPO4 lithium manganese phosphate, and when x takes 1, LiFePO4 is LiFePO4 lithium iron phosphate.

[0223] The weight ratio of the positive electrode active material in the positive electrode active layer is 80 wt% to 100 wt% based on the total weight of the positive electrode active layer.

[0224] In any embodiment of the present application, the components of the positive electrode active layer further include a positive electrode conductive agent and a positive electrode binder.

[0225] The positive electrode conductive agent described above can use a conductive agent commonly used in the art, including but not limited to at least one of graphite, carbon nanotubes, nanofibers, carbon black, and graphene. Specifically, it can be selected from at least one of SP, KS-6, acetylene black, branched structure ketchen black ECP, SFG-6, vapor grown carbon fiber VGCF, carbon nanotube CNTs, and graphene, and a composite conductive agent thereof.

[0226] The weight ratio of the positive electrode conductive agent in the positive electrode active layer is 0 to 20 wt% based on the total weight of the positive electrode active layer.

[0227] In any embodiment of the present application, the binder of the positive electrode binder described above can be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, hydrogenated nitrile rubber, styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS), and a fluorine-containing acrylate resin.

[0228] The weight ratio of the positive electrode binder in the positive electrode active layer is 0 to 30 wt% based on the total weight of the positive electrode active layer.

[0229] In some embodiments, the positive electrode sheet can be prepared by dispersing the components described above for preparing the positive electrode sheet in a solvent (such as N-methyl pyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry on the current collector, and after drying, cold pressing, etc., the positive electrode sheet is obtained. The solid content of the positive electrode slurry is 40 wt% to 80 wt%, and the viscosity at room temperature is adjusted to 5000 mPa·s to 25000 mPa·s. The positive electrode slurry is coated on the surface of the positive electrode current collector, dried, and then cold pressed by a cold rolling machine to form a positive electrode sheet; the unit area density of the positive electrode powder coating is 150 to 350 mg / m 2 , and the positive electrode sheet has a compacted density of 2.0 to 2.6 g / cm 3 . The formula for calculating the compacted density is:

[0230] Compacted density = coating area density / (thickness of the electrode sheet after extrusion - thickness of the current collector).

[0231] The compaction density and the area density of the positive electrode sheet are well known in the art, and the area density of the positive electrode sheet refers to the weight of the active layer loaded per unit area of the positive electrode sheet, unit area density = weight of the active layer / area of the active layer. As an example, the compaction density can be tested by the following steps:

[0232] The positive electrode sheet is cut into a film of 1000 mm in length; the positive electrode sheet is rolled by a certain pressure and then punched into a small disc of 1540.25 mm 2 The weight and thickness of the small disc are measured, and the compaction density is calculated.

[0233]

Negative electrode sheet

[0234] The negative electrode sheet comprises a positive electrode current collector and a negative active layer loaded on the surface of the positive electrode current collector, and the components of the negative active layer comprise a negative active material.

[0235] In some embodiments, the negative active layer is arranged on at least part of the surface of the current collector, including but not limited to: arranged on at least one surface of the current collector and arranged on both surfaces of the current collector.

[0236] In some embodiments, the current collector in the negative electrode sheet can adopt a metal foil or a composite current collector. For example, as the metal foil, a copper foil can be used. The composite current collector can comprise a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector can be formed by forming a metal material on a polymer material base material.

[0237] Optionally, the metal material comprises at least one of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

[0238] Optionally, the polymer material base material comprises at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).

[0239] The negative active material can use the common negative active material in the present application.

[0240] In any embodiment of the present application, the negative active material comprises at least one of mesocarbon microbeads, graphite, glassy carbon, carbon nanotubes, carbon-carbon composite material, carbon fiber, hard carbon, soft carbon, silicon-based material, tin-based material, magnesium-based material and iron-based material.

[0241] Optionally, the negative active material specifically includes, but is not limited to, at least one of mesocarbon microbeads, natural graphite, artificial graphite, graphene, glassy carbon, carbon nanotubes, carbon fibers, hard carbon, soft carbon, iron oxide, tin oxide, silicon oxide, magnesium oxide, and silicon-carbon composite.

[0242] In any embodiment of the present application, the mass percentage of the negative active material in the negative active layer is 70% to 99.5%.

[0243] In any embodiment of the present application, the negative active layer further includes a negative conductive agent and a negative binder.

[0244] In any embodiment of the present application, the negative conductive agent can be a conductive material commonly used in the art, including, but not limited to, at least one of graphite, carbon nanotubes, nanofibers, carbon black, and graphene. Specifically, it can be selected from at least one of SP, KS-6, acetylene black, branched structure Ketjen black ECP, SFG-6, vapor grown carbon fiber VGCF, carbon nanotube CNTs, and graphene, and a composite conductive agent thereof.

[0245] The weight percentage of the negative conductive agent in the negative active layer is 0 to 20 wt% based on the total weight of the negative active layer.

[0246] The negative binder can be a binder commonly used in the art, and can be selected from at least one of styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0247] The weight percentage of the negative binder in the negative active layer is 0 to 30 wt% based on the total weight of the negative active layer.

[0248] In any embodiment of the present application, the negative active layer can further optionally include other auxiliary agents, such as a thickening agent, for example, sodium carboxymethyl cellulose (CMC-Na) and the like. The weight percentage of the other auxiliary agent in the negative active layer is 0 to 15 wt% based on the total weight of the negative active layer.

[0249] In any embodiment of the present application, the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components, in a solvent (e.g. deionized water) to form a negative electrode slurry; coating the negative electrode slurry on a negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet is obtained. The negative electrode slurry has a solid content of 30 wt% to 70 wt%, and the viscosity at room temperature is adjusted to 2000 mPa·s to 10000 mPa·s; the obtained negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing (e.g. roll-to-roll), the negative electrode sheet is obtained. The negative electrode powder coating unit area density is 75 mg / m 2 ~220 mg / m 2 , and the negative electrode sheet compaction density is 1.2 g / m 3 ~2.0 g / m 3 .

[0250] The meanings of the area density and the compaction density are the same as above, and will not be repeated.

[0251]

Electrolyte

[0252] The electrolyte includes an electrolyte salt and a solvent

[0253] In some embodiments, the electrolyte salt can be selected from the electrolyte salts commonly used in the art, such as lithium ion electrolyte salts.

[0254] As an example, the lithium ion electrolyte salt includes but is not limited to one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethanesulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluoro-oxalato-borate (LiDFOB), lithium bis-oxalato-borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluoro-di-oxalato-phosphate (LiDFOP) and lithium tetrafluoro-oxalato-phosphate (LiTFOP).

[0255] In some embodiments, the solvent can be selected from one or more of fluoroethylene carbonate (FEC), ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0256] In some embodiments, the concentration of the electrolyte salt in the electrolyte is generally 0.5 mol / L to 1.5 mol / L.

[0257] In some embodiments, the electrolyte can optionally further include an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and can further include an additive capable of improving certain properties of the battery, such as an additive for improving overcharge performance of the battery, an additive for improving high-temperature or low-temperature performance of the battery, etc.

[0258]

Separator

[0259] The separator is disposed between the positive electrode sheet and the negative electrode sheet.

[0260] The type of the separator is not particularly limited in the present application, and any known porous structure separator having good chemical stability and mechanical stability can be used.

[0261] In some embodiments, the material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single layer film or a multi-layer composite film, and is not particularly limited. When the separator is a multi-layer composite film, the materials of the layers can be the same or different, and are not particularly limited.

[0262] The thickness of the separator is controlled to be 2 μm to 15 μm; alternatively, the thickness of the separator is controlled to be 2 μm to 13 μm.

[0263] In some embodiments, the above-described battery is a secondary battery; specifically, the above-described battery is a lithium ion battery.

[0264] Specifically, the positive electrode sheet, the negative electrode sheet, and the separator can be formed into an electrode assembly through a winding process or a stacking process. The electrode assembly is encapsulated in the accommodation cavity formed by the above-described composite plastic film material, and the electrolyte is impregnated in the electrode assembly. The number of the electrode assemblies contained in the battery can be one or more, and can be adjusted according to the requirements.

[0265] The application also provides a power consuming device comprising the above-mentioned battery.

[0266] Further, in the above-mentioned power consuming device, the secondary battery can exist in the form of a battery monomer or further assembled in the form of a battery pack.

[0267] The battery pack comprises a battery box and one or more batteries arranged in the battery box. The battery box comprises an upper box body and a lower box body, and the upper box body can be arranged on the lower box body to form a closed space for the batteries.

[0268] The plurality of batteries can be arranged in the battery box in any manner.

[0269] The above-mentioned battery or the battery pack assembled therefrom can be used as a power source of a power consuming device or as an energy storage unit of a power consuming device.

[0270] The above-mentioned power consuming device can be, but is not limited to, a mobile device (such as a mobile phone, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc.

[0271] As an example of the power consuming device, it can be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the high power and high energy density requirements of the power consuming device for the battery, a battery pack can be used.

[0272] As another example of the power consuming device, it can be a mobile phone, a tablet computer, a notebook computer, etc. The device usually requires thinning, and a battery can be used as a power source.

[0273] The application will be described in detail below with reference to specific embodiments, but the application is not limited to the following embodiments. It should be understood that the appended claims generalize the scope of the application, and those skilled in the art should realize that certain changes to the embodiments of the application will be covered by the spirit and scope of the claims.

[0274] The following are specific embodiments. Specific Embodiments

[0275] Embodiment 1

[0276] 1. Preparation of a composite metal layer:

[0277] S1: provide an electroplating solution, the concentration of NiSO4 in the electroplating solution is 100 g / L, the concentration of NiCl2 is 25 g / L, the concentration of FeSO4 is 50 g / L, the surfactant is sodium dodecyl sulfonate, the concentration is 1.5 g / L, the concentration of boric acid is 20 g / L, and the pH value is 2.5.

[0278] S2: the anode material used for electroplating is iron block and nickel block, the cathode material is titanium alloy, the control current is 9.8 A / cm 2 , the plating solution temperature is 55℃, the nickel and iron elements will be deposited on the surface of the titanium alloy during the electroplating process, the electroplating roller speed is 1.2 m / min, and after the deposition is completed, the deposition layer is peeled off from the titanium alloy to obtain a composite metal layer.

[0279] S3: test the physical property parameters of the composite metal layer:

[0280] (1) Test the mass percentage of each element in the whole composite metal layer. Specifically, the composite metal layer is quenched in liquid nitrogen to obtain a cross section, and then the element content of the cross section is tested using a spectrometer (Oxford X-max-50mm2) B~U and a table top electron microscope (FEI ProX) B-Am. First, the position is calibrated using an electron microscope, and then the element content at the position is tested using a spectrometer. The standard GB-T17359-2012 microbeam analysis energy spectrum method is used for quantitative analysis.

[0281] Among them, the positions corresponding to the center layer of the two surface layers and the 1 / 2 thickness of the composite metal layer in the cross section are calibrated using an electron microscope, and then the mass percentage of nickel element in the two surface layers and the center layer is tested using the above mass percentage test method.

[0282] Among them, the thickness of the two surface layers is 2μm, and the thickness of the center layer is 4μm. The specific results are shown in Table 1. The mass percentage of nickel element in the two surface layers and the center layer is respectively Y1, Y2, Y3, and the specific results are shown in Table 1.

[0283] Among them, the mass percentage of nickel element in the whole composite metal layer is K1%, and the mass percentage of iron element in the composite metal layer is K2%, and the specific results are shown in Table 1.

[0284] (2) The thickness of the composite metal layer is tested. The known method in the art can be used for testing. Specifically, the step gauge test method is used for testing: the measuring needle of the step gauge lightly scratches the surface of the sample with very small force, and the micron or even nanometer level of the sample surface is amplified by the sensor connected with the measuring needle by millions of times, and then converted into an electronic signal and input into the computer software, finally displayed in the form of digital and graphical data, or directly measured with a ruler. The thickness of the composite metal layer is D, and the specific results are shown in Table 1.

[0285] (3) Test the roughness of the two surfaces of the composite metal layer:

[0286] The surface roughness can be tested by a conventional test method for testing surface roughness in the art, which is specifically referred to the standard GB1031-83. The roughness of the two surfaces of the composite metal layer, i.e. the first surface and the second surface, is denoted as λ1 and λ2 respectively. The specific results are shown in Table 1.

[0287] (3) Test the tensile strength of the composite metal layer: measure the length and width of the composite metal layer sample with a gauge to the nearest 0.05 mm, symmetrically clamp the sample in the upper and lower clamps of the gauge, start the gauge and keep it at (5±1) mm / min, record the maximum load at which the composite metal layer sample is sheared and broken, and then calculate the tensile strength σ of the sample according to the following formula: t :

[0288] σ t = p / (b x d)

[0289] wherein P is the maximum load (N), b is the width of the sample (mm), and d is the thickness of the sample.

[0290] The specific results are shown in Table 1.

[0291] 2. Preparation of the composite plastic film

[0292] S1: The specific process is as follows: use the traditional dry lamination process to glue one surface of the composite metal layer, then laminate with the nylon layer to form the first plastic film layer, glue the other surface, and then laminate with the cast polypropylene layer (CPP layer) to form the second plastic film layer, and dry to obtain the composite plastic film. The CPP layer is 40 μm, the nylon layer is 25 μm, the composite metal layer is 30 μm, and the formed adhesive layer is 4 μm. The gluing step uses polyolefin adhesive NF308H.

[0293] S2: Test the properties of the composite plastic film:

[0294] (1) Test method for penetration resistance: take 5 pieces of 100 x 100 mm 2 composite plastic film, install a 1 mm diameter steel needle on the electronic tensile testing machine, press it to the composite plastic film at a speed of 50 mm / min, record the reading of the electronic tensile testing machine at the time of penetration, which is the penetration resistance (N), and take the average value;

[0295] (2) Test method for strain: take 5 pieces of 10 cm x 30 mm composite plastic film, place them on the tensile testing machine, test the deformation amount when the tensile force reaches 50 N, and the distance between the tensile clamps is 5 cm; deformation amount = (length when the tensile force reaches 50 N - original length) / original length x 100%, which can be directly read by the software matched with the tensile testing machine.

[0296] (3) Adhesion test: after the composite plastic film is soaked in electrolyte for 24 hours, 3 composite plastic films of 10 cm x 30 mm are taken, and the adhesion between the first plastic film layer and the functional film layer is tested; the specific process is as follows:

[0297] 180° test method is adopted: that is, the sample test surface is pasted on a stainless steel plate by double-sided tape, the stainless steel plate is fixed on the lower jaw of the tensile testing machine, the bottom end of the sample is pulled open and fixed on the upper jaw of the tensile testing machine, the tensile speed is 100 mm / min, the fixed displacement is 70 mm, and the adhesion is measured.

[0298] The electrolyte composition includes a solvent and a lithium salt, the solvent is ethylene carbonate (EC), methyl ethyl carbonate (EMC) and diethyl carbonate (DEC) in a volume ratio of 1:1:1, and the lithium salt is lithium hexafluorophosphate with a concentration of 1M.

[0299] (4) Resistance to electrolyte corrosion: the metal plastic film PP layer is artificially scratched, assembled into a battery, fully charged, and placed at 45°C for 24 hours. The content of nickel metal ions in the electrolyte is tested by ICP (inductively coupled plasma emission spectrometry), and the content is T1 ppm. The preparation process of the battery is as follows:

[0300] S1. Preparation of positive electrode sheet

[0301] The positive electrode active material lithium iron phosphate, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) are dissolved in the solvent N-methyl pyrrolidone (NMP) in a weight ratio of 96.2:1:2.8, and after being fully stirred and mixed uniformly, a positive electrode slurry is obtained. Then the positive electrode slurry is uniformly coated on the positive electrode current collector, and then dried, cold-pressed and cut to obtain the positive electrode sheet.

[0302] S2. Preparation of negative electrode sheet

[0303] The negative electrode active material graphite, the conductive agent acetylene black, the thickening agent sodium hydroxymethyl cellulose (CMC), and the binder styrene butadiene rubber (SBR) are mixed uniformly in water in a mass ratio of 96.5:0.5:1.2:1.8 to prepare a negative electrode slurry. The negative electrode slurry is uniformly coated on the negative electrode current collector copper foil, dried, and then cold-pressed to prepare the negative electrode sheet.

[0304] S3. Preparation of electrolyte: the organic solvent is a mixed solution containing ethylene carbonate (EC), methyl ethyl carbonate (EMC) and diethyl carbonate (DEC), wherein the volume ratio of EC, EMC and DEC is 1:1:1. In an argon atmosphere glove box with water content <10 ppm, LiPF6 is dissolved in the organic solvent, and the electrolyte is obtained after mixing uniformly, wherein the concentration of LiPF6 is 1 mol / L.

[0305] S4. Separation film: polyethylene microporous film is used as the porous separation film substrate.

[0306] S5, preparation of the lithium ion battery: the positive electrode sheet, the negative electrode sheet and the separator film are wound to obtain a bare battery cell, and then the composite plastic film packaging, liquid injection, formation, exhaust and other processes are adopted to prepare a soft package lithium ion battery.

[0307] Examples 2-5

[0308] Examples 2-5 are basically the same as Example 1, except that in the preparation process of the composite metal layer, the concentrations of nickel sulfate, nickel chloride and iron sulfate in the electroplating solution are changed to make the mass proportions of nickel and iron elements in the overall composite metal layer different from Example 1. In Examples 2-5, the concentration of nickel sulfate in the electroplating solution is 1500 g / L, 1650 g / L, 850 g / L, 70 g / L, respectively, the concentration of nickel chloride is 65 g / L, 58 g / L, 42 g / L, 36 g / L, respectively, and the concentration of iron sulfate is 40 g / L, 34 g / L, 72 g / L, 85 g / L, respectively. For details, see the parameters in Table 1.

[0309] The other step conditions are the same as those in Example 1, and the test results are shown in Table 1.

[0310] Examples 6-7

[0311] Examples 6-7 are basically the same as Example 1, except that in the preparation process of the composite metal layer, the concentration of boric acid in the electroplating solution is changed, and the concentration of the surfactant is adjusted to change the pH value of the electroplating solution in Examples 6-7, so that the roughness of the two surface layers of the composite metal layer is different from Example 1. In Examples 6-7, the pH value of the electroplating solution is 2 and 3.5, respectively.

[0312] The other step conditions are the same as those in Example 1, and the test results are shown in Table 1.

[0313] Examples 8-10

[0314] Examples 8-10 are basically the same as Example 1, except that in the preparation process of the composite metal layer, the electroplating roller speed and current size during electroplating treatment are changed to make the thickness of the composite metal layer different from Example 1. In Examples 8-10, the electroplating roller speed is 1.6 m / min, 1.4 m / min, 1.0 m / min, respectively, and the current is 8.5 A / dm 2 , 9.2 A / dm 2 , 10.8 A / dm 2 .

[0315] The other step conditions are the same as those in Example 1, and the test results are shown in Table 1.

[0316] Example 11

[0317] Example 11 is basically the same as Example 5, except that the preparation process of the composite metal layer is as follows: first, a 4 μm-thick composite metal center layer is prepared by electroplating according to the preparation process of the composite metal layer in Example 1, then vacuum evaporation is performed on both surfaces of the center layer, and the nickel content in the nickel-iron target is increased continuously during the vacuum evaporation, and finally, pure nickel target is used to perform vacuum evaporation to obtain two surface layers each with a thickness of 2 μm, thereby obtaining the composite metal layer.

[0318] The other step conditions are the same as those in Example 5, and the test results are shown in Table 1.

[0319] Example 12

[0320] Example 12 is basically the same as Example 5, except that the thickness of the composite metal layer is changed during the preparation process of the composite plastic film, and a Cr layer is formed on both surfaces of the composite metal layer by magnetron sputtering to form two corrosion-resistant layers with the same thickness.

[0321] The other step conditions are the same as those in Example 5, and the test results are shown in Table 1.

[0322] Examples 13-14

[0323] Examples 13-14 are the same as Example 12, except that the thicknesses of the corrosion-resistant layers are different.

[0324] The other step conditions are the same as those in Example 5, and the test results are shown in Table 1.

[0325] Examples 15-16

[0326] Examples 15-16 are the same as Example 1, except that the amount of glue is adjusted during gluing to form bonding layers with different thicknesses.

[0327] The other step conditions are the same as those in Example 1, and the test results are shown in Table 1.

[0328] Example 17

[0329] Example 17 is the same as Example 1, except that during the preparation process of the composite plastic film, the surface of the nylon material layer away from the functional layer is glued and then laminated with a polyethylene terephthalate layer with a thickness of 15 μm, and at this time, the thickness of the first plastic film layer is the sum of the thicknesses of the polyethylene terephthalate layer and the nylon layer.

[0330] The other step conditions are the same as those in Example 1, and the test results are shown in Table 1.

[0331] Comparative Example 1

[0332] Comparative Example 1 is basically the same as Example 1, except that an aluminum foil layer is used instead of the composite metal layer in the preparation of the composite plastic film.

[0333] The other step conditions are the same as those in Example 1, and the test results are shown in Table 1.

[0334] Comparative Example 2

[0335] Comparative Example 2 is basically the same as Example 1, except that an iron foil layer is used instead of the composite metal layer in the preparation of the composite plastic film.

[0336] The other step conditions are the same as those in Example 1, and the test results are shown in Table 1.

[0337] Comparative Example 3

[0338] Comparative Example 3 is basically the same as Example 1, except that a nickel foil layer is used instead of the composite metal layer in the preparation of the composite plastic film.

[0339] The other step conditions are the same as those in Example 1, and the test results are shown in Table 1.

[0340] Comparative Example 4

[0341] Comparative Example 4 is basically the same as Example 1, except that the concentration of nickel sulfate in the electroplating solution is 50 g / L, the concentration of nickel chloride is 20 g / L, and the concentration of iron sulfate is 85 g / L in the preparation of the composite metal layer, so that the mass percentage of nickel and iron elements in the prepared composite metal layer is different from that of Example 1. The specific parameters are shown in Table 1.

[0342] The other step conditions are the same as those in Example 1, and the test results are shown in Table 1.

[0343] The parameters and related performance data involved in each example and comparative example are shown in Table 1. The mass percentage of nickel element in the composite metal layer is denoted as K1%, the mass percentage of iron element in the composite metal layer is denoted as K2%, the mass percentage of nickel element in the two surface layers and the center layer is denoted as Y1, Y2, and Y3, respectively, the roughness of the first surface and the second surface is denoted as λ1 and λ2, respectively, and σ t is the tensile strength of the composite metal layer; in the electrolyte corrosion resistance test, the metal ion content in the electrolyte is T1 ppm.

[0344] Table 1

[0345]

[0346] Note: " / " in the table represents the absence of the structure or component.

[0347] As can be seen from the data in Table 1, the composite plastic film material of the present application has excellent penetration resistance and corrosion resistance, even if the amount of adhesive is reduced, i.e. the thickness of the adhesive layer is reduced, it still has excellent penetration resistance, corrosion resistance and bonding strength.

[0348] The technical features of the above-described embodiments can be combined in any manner. For the sake of brevity, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combination of the technical features does not result in a contradiction, it should be considered within the scope of the present disclosure.

[0349] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present patent should be subject to the appended claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. A composite plastic film material, characterized in that, The composite plastic film material includes a first plastic film layer, a functional film layer, and a second plastic film layer that are stacked sequentially. The functional membrane layer includes a composite metal layer, the components of which include nickel and iron, and the mass percentage K1% of nickel in the composite metal layer satisfies: 50%≤K1%≤90%; the mass percentage K1% of nickel and the mass percentage K2% of iron in the composite metal layer satisfy: K1%+K2%≥98%.

2. The composite plastic film material as described in claim 1, characterized in that, K1% satisfies: 65%≤K1%≤85%.

3. The composite plastic film material according to any one of claims 1 to 2, characterized in that, The mass percentage K2% of iron in the composite metal layer satisfies: K2%≥10%.

4. The composite plastic film material as described in claim 3, characterized in that, K2% satisfies: 10%≤K2%≤49%.

5. The composite plastic film material according to any one of claims 1 to 2, characterized in that, The composite metal layer satisfies at least one of the following conditions (1) to (3): (1) The thickness of the composite metal layer is 20μm~40μm; (2) The surface roughness of at least one surface of the composite metal layer is 0.8~3.2μm; (3) The tensile strength of the composite metal layer is 600 MPa~910 MPa.

6. The composite plastic film material as described in claim 5, characterized in that, The thickness of the composite metal layer is 25μm~35μm.

7. The composite plastic film material as described in claim 5, characterized in that, The surface roughness of at least one surface of the composite metal layer is 1.6 μm to 3.2 μm.

8. The composite plastic film material according to any one of claims 1 to 2, characterized in that, The functional membrane layer satisfies at least one of the following conditions (4) to (5): (4) The functional film layer further includes a first corrosion-resistant metal layer disposed on the side of the composite metal layer near the first plastic film layer; (5) The functional film layer further includes a second corrosion-resistant metal layer disposed on the side of the composite metal layer near the second plastic film layer.

9. The composite plastic film material as described in claim 8, characterized in that, The thickness of the first corrosion-resistant metal layer is 1μm to 5μm.

10. The composite plastic film material as described in claim 8, characterized in that, The metal in the first corrosion-resistant metal layer includes at least one of Al, Cr, and Ni.

11. The composite plastic film material as described in claim 8, characterized in that, The thickness of the second corrosion-resistant metal layer is 1 μm to 5 μm.

12. The composite plastic film material as described in claim 8, characterized in that, The metal in the second corrosion-resistant metal layer includes at least one of Al, Cr, and Ni.

13. The composite plastic film material as described in claim 8, characterized in that, The thickness of the functional film is 20 μm to 40 μm.

14. The composite plastic film material as described in claim 13, characterized in that, The thickness of the functional film is 25 μm to 40 μm.

15. The composite plastic film material as described in claim 13, characterized in that, The thickness of the functional film is 25 μm to 35 μm.

16. The composite plastic film material according to any one of claims 1 to 2, characterized in that, The mass percentage of nickel in at least one surface layer of the composite metal layer is H1, and the mass percentage of nickel in any layer between the two surface layers of the composite metal layer is H2, wherein H1 and H2 satisfy: H1 > H2.

17. The composite plastic film material as described in claim 16, characterized in that, The mass percentage of nickel in both outer layers of the composite metal layer is selected from H1.

18. The composite plastic film material as described in claim 16, characterized in that, The thickness of the surface layer is 1 μm to 5 μm.

19. The composite plastic film material as described in claim 16, characterized in that, H1 satisfies: 75%≤H1≤100%.

20. The composite plastic film material as described in claim 16, characterized in that, With the layer at half the thickness of the composite metal layer as the central layer, the mass percentage of nickel distributed in the direction extending vertically from the central layer to at least one surface layer of the composite metal layer shows an increasing trend.

21. The composite plastic film material as described in claim 20, characterized in that, In the directions that extend vertically from the central layer to the two surface layers of the composite metal layer, the mass percentage of nickel increases.

22. The composite plastic film material as described in claim 20, characterized in that, The thickness of the central layer is 2μm to 10μm.

23. The composite plastic film material as described in claim 20, characterized in that, In the composite metal layer, the mass percentage of nickel distributed in the layers on both sides of the central layer is symmetrical about the central layer as the axis of symmetry.

24. The composite plastic film material as described in claim 23, characterized in that, The thickness of the composite metal layer is D μm, the mass percentage of nickel in any layer between the surface layer and the center layer of the composite metal layer is Y, and the vertical distance from any layer between the surface layer and the center layer of the composite metal layer to the center layer is R, where H = 2R / D; Y and the mass percentage K1% of nickel in the composite metal layer satisfy the following relationship: Y = (2-2K1%)×H + 2K1% - 1, (2K1%-1) ≤ Y ≤ 1.

25. The composite plastic film material according to any one of claims 1 to 2, characterized in that, The second plastic film layer satisfies at least one of the following conditions (6) to (7): (6) The thickness of the second plastic film layer is 30μm~50μm; (7) The components of the second plastic film layer include polypropylene.

26. The composite plastic film material according to any one of claims 1 to 2, characterized in that, The components of the first plastic film layer include at least one of nylon material and polyethylene terephthalate.

27. The composite plastic film material as described in claim 26, characterized in that, The first plastic film layer includes at least one of a nylon material layer and a polyethylene terephthalate layer.

28. The composite plastic film material as described in claim 27, characterized in that, The first plastic film layer comprises a nylon material layer and a polyethylene terephthalate layer stacked sequentially, and the nylon material layer is closer to the functional film layer than the polyethylene terephthalate layer.

29. The composite plastic film material as described in claim 28, characterized in that, The thickness of the nylon material layer is 20μm to 30μm, and the thickness of the polyethylene terephthalate layer is 5μm to 20μm.

30. The composite plastic film material according to any one of claims 1 to 2, characterized in that, There are also adhesive layers between the various layers.

31. The composite plastic film material as described in claim 30, characterized in that, The thickness of each adhesive layer is independently selected from 1 μm to 5 μm.

32. The composite plastic film material as described in claim 31, characterized in that, The thickness of each adhesive layer is independently selected from 1 μm to 2 μm.

33. The composite plastic film material as described in claim 30, characterized in that, The adhesive component of the adhesive layer includes at least one of polyolefin resin, epoxy resin, polyurethane, polyester polyol and polyisocyanate.

34. The method for preparing the composite plastic film material according to any one of claims 1 to 33, characterized in that, The preparation steps of the composite metal layer include the following: An anode material and a cathode material are provided; the anode material includes nickel and iron, and the cathode material is a titanium alloy. The anode and cathode materials are placed in an electroplating solution for electroplating treatment, and nickel and iron elements are deposited on the surface of the cathode material to form the composite metal layer. The electroplating solution comprises nickel salt, iron salt, and water. Alternatively, it may include the following steps for preparing the composite metal layer: The composite metal layer is prepared by physical vapor deposition using a target material; the target material comprises nickel and iron.

35. The method for preparing the composite plastic film material as described in claim 34, characterized in that, The electroplating process satisfies at least one of the following conditions (8) to (10): (8) The current for the electroplating process is 9.5 A / cm. 2 ~10.8A / cm 2 ; (9) The electroplating temperature is 45℃~60℃; (10) The electroplating speed is 1.0 m / min to 1.6 m / min.

36. The method for preparing the composite plastic film material according to any one of claims 34-35, characterized in that, The electroplating solution satisfies at least one of the following conditions (11) to (13): (11) The pH value of the electroplating solution is 2~3.5; (12) In the electroplating solution, the concentration of the nickel salt is 100 g / L to 150 g / L, and the concentration of the iron salt is 25 g / L to 75 g / L; (13) The components of the electroplating solution also include surfactants.

37. The method for preparing the composite plastic film material as described in claim 36, characterized in that, The nickel salts include water-soluble nickel salts.

38. The method for preparing the composite plastic film material as described in claim 36, characterized in that, The nickel salt includes at least one of NiSO4 and NiCl2.

39. The method for preparing the composite plastic film material as described in claim 36, characterized in that, The iron salts include water-soluble iron salts.

40. The method for preparing the composite plastic film material as described in claim 36, characterized in that, The iron salt includes FeSO4.

41. The method for preparing the composite plastic film material as described in claim 36, characterized in that, The concentration of the surfactant is 1 g / L to 2.5 g / L.

42. The method for preparing the composite plastic film material as described in claim 36, characterized in that, The surfactants include anionic surfactants.

43. The method for preparing the composite plastic film material as described in claim 36, characterized in that, The surfactant includes at least one of sodium dodecyl sulfonate and sodium dodecyl sulfate.

44. A battery, characterized in that, The battery comprises the composite plastic film material as described in any one of claims 1 to 33.

45. An electrical appliance, characterized in that, The electrical device includes the battery as described in claim 44.

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