Metal-plastic composite film for battery outer package and secondary battery

Abstract

The invention relates to the field of battery outer packing, in particular to a metal-plastic composite film for battery outer packing and a secondary battery. The metal-plastic composite film for the outer package of the battery comprises an outer base material resin layer, a middle metal layer, an inner adhesive layer and an inner hot melting resin layer which are sequentially stacked, wherein the outer base material resin layer comprises resin; a dynamic thermomechanical analysis spectrogram of the resin has a first characteristic peak in a range of 60-120 DEG C, a second characteristic peak in a range of 0-50 DEG C, and a third characteristic peak in a range of-30--90 DEG C; the peak height of the first characteristic peak is lt; 0.5, the peak height of the second characteristic peak is lt; 0.2, the peak height lt of the third characteristic peak; and 0.2 part. The outer base material resin layer with extremely high formability is obtained by designing the molecular and molecular chain motion temperature of the resin for preparing the outer base material resin layer and the ratio of the storage modulus to the loss modulus, and after the outer base material resin layer is compounded into the metal-plastic composite film, the forming capacity is remarkably improved, and the metal-plastic composite film is suitable for large-scale production. And the high forming requirement of the soft package lithium battery on the outer package material can be met.

Description

Technical Field

[0001] The invention relates to the field of battery outer packaging, in particular to a gold-plastic composite film for battery outer packaging and a secondary battery. Background Art

[0002] At present, lithium-ion batteries are mainly divided into three categories according to their packaging shape: square, cylindrical, and soft-pack. The soft-pack shell uses a metal-plastic composite film, which is a composite film material made by bonding metal foil and resin film with a specific adhesive. Therefore, it has the characteristics of light weight and strong plasticity.

[0003] The composition of the metal-plastic composite film from the outside to the inside is the outer substrate resin layer, the middle metal layer, the inner adhesive layer and the inner heat-welding resin layer. As the outer packaging material of lithium batteries, the function of the outer substrate resin layer is to improve the formability, so the film used for the outer substrate resin layer must have a certain strength and tensile property. In order to meet this requirement, the outer substrate resin layer uses a film that has been stretched and oriented by double-stretching or film blowing process. Because the film is stretched, the molecules and molecular chains will be oriented in the stretching direction, so the thermal motion properties and thermal motion laws of the molecules and molecular chains will change compared to before the stretching alignment. The thermal motion properties and thermal motion laws of the molecules and molecular chains of the film are crucial to the stress deformation of the film in actual use, which is reflected in the outer packaging material of lithium batteries as the molding ability of the outer packaging material of lithium batteries. Based on this, the design of the thermal motion properties of the outer substrate resin layer film material selected for the outer packaging material of soft-pack lithium batteries is very important.

[0004] In the past, people usually did not pay attention to the influence of film thermal motion performance on formability, and then did not confirm and manage the film thermal motion performance. They often adjusted the film formability by controlling the stretch ratio during film production. In practical applications, the control of the stretch ratio is manifested in the confirmation and management of the stress-strain curve (hereinafter referred to as SS curve test) of the outer substrate resin layer film on the lithium battery outer packaging material. However, the stretch ratio cannot be used as a representative indicator for measuring formability, especially the formability of the material under different temperatures, speeds, and pressures. The results of the SS curve are also limited by sample preparation and often cannot accurately reflect the formability of the film, especially the formability of the material under different temperatures, speeds, and pressures.

[0005] If the deformation of the metal-plastic composite film is too large and exceeds the deformation limit of the metal-plastic composite film, it will cause rupture. The deformation limit depends on the outer substrate resin layer and the intermediate metal layer. As the outer substrate resin layer, the molecular and molecular chain thermal motion properties of the resin used to prepare the outer substrate resin layer are particularly important. With the pursuit of energy density for soft-pack lithium batteries, the molding depth of the metal-plastic composite film is also required to be improved. The outer substrate resin layer materials of the existing technology can no longer meet the high molding requirements of soft-pack lithium batteries. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the present invention provides a gold-plastic composite film for battery outer packaging and a secondary battery. The gold-plastic composite film for battery outer packaging includes an outer substrate resin layer, and the outer substrate resin layer contains resin. By designing the molecules of the resin, the temperature of the molecular chain movement, and the ratio of the storage modulus to the loss modulus, an outer substrate resin layer with extremely high formability is prepared. After the outer substrate resin layer is used to compound the gold-plastic composite film, the forming ability is significantly improved, and the high forming requirements of the outer packaging material of the soft-pack lithium battery can be met.

[0007] To this end, the first aspect of the present invention provides a metal-plastic composite film for battery outer packaging, the metal-plastic composite film for battery outer packaging comprising an outer substrate resin layer, an intermediate metal layer, an inner adhesive layer and an inner heat-welding resin layer stacked in sequence;

[0008] The outer substrate resin layer comprises a resin; the dynamic thermomechanical analysis spectrum of the resin has a first characteristic peak in the range of 60°C to 120°C, a second characteristic peak in the range of 0°C to 50°C, and a third characteristic peak in the range of -30°C to -90°C;

[0009] The peak height of the first characteristic peak is <0.5, the peak height of the second characteristic peak is <0.2, and the peak height of the third characteristic peak is <0.2.

[0010] When the resin is subjected to dynamic thermomechanical analysis, the analyzer sets a temperature change program, and the real-time temperature displayed by the analyzer is the current motion temperature of the resin molecules and molecular chains, and the peak height of the characteristic peak can be considered as the ratio of the storage modulus to the loss modulus. The present invention prepares an outer substrate resin layer with extremely high formability by designing the motion temperature of the molecules and molecular chains of the resin used to prepare the outer substrate resin layer, and the ratio of the storage modulus to the loss modulus. After the outer substrate resin layer is compounded into a metal-plastic composite film, the forming ability of the metal-plastic composite film can be significantly improved, thereby solving the problem of insufficient forming ability of soft-pack lithium batteries in the prior art.

[0011] According to an embodiment of the present invention, the dynamic thermomechanical analysis spectrum of the resin has a first characteristic peak in the range of 80°C to 100°C.

[0012] According to an embodiment of the present invention, the peak height of the first characteristic peak is less than 0.3, preferably less than 0.2.

[0013] According to an embodiment of the present invention, the dynamic thermomechanical analysis spectrum of the resin has a second characteristic peak in the range of 20°C to 40°C.

[0014] According to an embodiment of the present invention, the dynamic thermomechanical analysis spectrum of the resin has a third characteristic peak in the range of -60°C to -80°C.

[0015] According to an embodiment of the present invention, the peak height of the third characteristic peak is <0.15.

[0016] According to an embodiment of the present invention, the resin includes polyamide, and the polyamide includes aliphatic polyamide.

[0017] According to an embodiment of the present invention, the aliphatic polyamide includes at least one of nylon 6, nylon 66, nylon 610, nylon 12, and nylon 46.

[0018] According to an embodiment of the present invention, the resin includes a copolymer of nylon 6 and nylon 66.

[0019] According to an embodiment of the present invention, the ratio of nylon 6 to nylon 66 in the copolymer of nylon 6 and nylon 66 is (100-1):(1-100).

[0020] A second aspect of the present invention provides a secondary battery, wherein the secondary battery comprises the gold-plastic composite film for battery outer packaging as described in the first aspect.

[0021] The outer substrate resin layer provided by the present invention has extremely high formability. After being compounded into a metal-plastic composite film, the formability of the metal-plastic composite film is significantly improved, which can meet the high drawing depth requirements of soft-pack lithium batteries and improve their drawing depth capabilities, especially the drawing depth capabilities under different temperatures, speeds and pressures, thereby solving the problem of insufficient forming capacity of soft-pack lithium batteries in the prior art.

[0022] The beneficial effects of the present invention compared to the prior art are as follows:

[0023] The invention provides an outer substrate resin layer. By designing the molecules of the resin for preparing the outer substrate resin layer, the movement temperature of the molecular chain, and the ratio of the storage modulus to the loss modulus, an outer substrate resin layer with extremely high formability is prepared. After the outer substrate resin layer is compounded into a metal-plastic composite film, the forming ability is significantly improved, and the high forming requirements of soft-pack lithium batteries for outer packaging materials can be met, and the film has high industrial utilization value.

[0024] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0026] Figure 1 The schematic diagram of the structure of the gold-plastic composite film for battery outer packaging according to the present invention is shown.

[0027] Reference numerals:

[0028] An outer base resin layer 1, an outer adhesive layer 2, an intermediate metal layer 3, an inner adhesive layer 4, and an inner heat-welding resin layer 5. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0030] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0031] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0032] In order to make the present invention more easily understood, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which the present invention belongs.

[0033] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0034] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0035] According to an embodiment of the present invention, a first aspect of the present invention provides a gold-plastic composite film for battery outer packaging, the gold-plastic composite film for battery outer packaging comprising an outer substrate resin layer, an intermediate metal layer, an inner adhesive layer and an inner heat-welding resin layer stacked in sequence;

[0036] The outer substrate resin layer comprises a resin; the dynamic thermomechanical analysis spectrum of the resin has a first characteristic peak in the range of 60°C to 120°C, a second characteristic peak in the range of 0°C to 50°C, and a third characteristic peak in the range of -30°C to -90°C;

[0037] The peak height of the first characteristic peak is <0.5, the peak height of the second characteristic peak is <0.2, and the peak height of the third characteristic peak is <0.2.

[0038] The present invention designs the molecules of the resin for preparing the outer substrate resin layer, the molecular chain motion temperature, and the ratio of the storage modulus to the loss modulus, thereby preparing an outer substrate resin layer with extremely high formability. After the outer substrate resin layer is compounded into a metal-plastic composite film, the formability of the metal-plastic composite film can be significantly improved, thereby solving the problem of insufficient formability of soft-pack lithium batteries in the prior art.

[0039] According to a specific embodiment of the present invention, the gold-plastic composite film for battery outer packaging further comprises an external adhesive layer, and the external adhesive layer is located between the outer base material resin layer and the intermediate metal layer.

[0040] According to a specific embodiment of the present invention, the dynamic thermomechanical analysis spectrum of the resin has a first characteristic peak in the range of 80°C to 100°C.

[0041] According to a specific embodiment of the present invention, the peak height of the first characteristic peak is <0.3, preferably the peak height is <0.2. As some specific examples, the peak height of the first characteristic peak may be 0.22, 0.18, 0.16, 0.15, 0.14, etc.

[0042] According to a specific embodiment of the present invention, the dynamic thermomechanical analysis spectrum of the resin has a second characteristic peak in the range of 20°C to 40°C.

[0043] According to a specific embodiment of the present invention, the dynamic thermomechanical analysis spectrum of the resin has a third characteristic peak in the range of -60°C to -80°C.

[0044] According to a specific embodiment of the present invention, the peak height of the third characteristic peak is less than 0.15. As some specific examples, the peak height of the third characteristic peak may be 0.16, 0.12, 0.1, 0.09, 0.08, etc.

[0045] According to a specific embodiment of the present invention, the resin includes polyamide, the polyamide includes aliphatic polyamide, the type of the aliphatic polyamide is not particularly limited, and as some specific examples, the aliphatic polyamide includes at least one of nylon 6, nylon 66, nylon 610, nylon 12, and nylon 46.

[0046] According to a specific embodiment of the present invention, the resin includes a copolymer of nylon 6 and nylon 66.

[0047] According to a specific embodiment of the present invention, the ratio of nylon 6 to nylon 66 in the copolymer of nylon 6 and nylon 66 is (100-1):(1-100). As some specific examples, the ratio of nylon 6 to nylon 66 in the copolymer of nylon 6 and nylon 66 may be 100:1, 1:1, 1:100, etc.

[0048] According to an embodiment of the present invention, a second aspect of the present invention provides a secondary battery, wherein the secondary battery comprises the gold-plastic composite film for battery outer packaging as described in the first aspect.

[0049] The outer substrate resin layer provided by the present invention has extremely high formability. After being compounded into a metal-plastic composite film, the formability of the metal-plastic composite film is significantly improved, which can meet the high drawing depth requirements of soft-pack lithium batteries and improve their drawing depth capabilities, especially the drawing depth capabilities under different temperatures, speeds and pressures, thereby solving the problem of insufficient forming capacity of soft-pack lithium batteries in the prior art.

[0050] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0051] Example 1

[0052] The present embodiment provides a gold-plastic composite film for battery outer packaging, wherein the structure of the gold-plastic composite film comprises, from outside to inside, an outer substrate resin layer 1, an outer adhesive layer 2, an intermediate metal layer 3, an inner adhesive layer 4 and an inner heat-welding resin layer 5, wherein the material of the outer substrate resin layer 1 comprises nylon 6, and the dynamic thermomechanical analysis spectrum of the nylon 6 has a first characteristic peak in the range of 80°C to 100°C, with a peak height of <0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of <0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of <0.15.

[0053] Example 2

[0054] The present embodiment provides a gold-plastic composite film for battery outer packaging, wherein the structure of the gold-plastic composite film comprises, from outside to inside, an outer substrate resin layer 1, an outer adhesive layer 2, an intermediate metal layer 3, an inner adhesive layer 4 and an inner heat-welding resin layer 5, wherein the material of the outer substrate resin layer 1 comprises nylon 66, and the dynamic thermomechanical analysis spectrum of the nylon 66 has a first characteristic peak in the range of 80°C to 100°C, with a peak height of <0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of <0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of <0.15.

[0055] Example 3

[0056] The present embodiment provides a gold-plastic composite film for battery outer packaging, wherein the structure of the gold-plastic composite film comprises, from outside to inside, an outer base resin layer 1, an outer adhesive layer 2, an intermediate metal layer 3, an inner adhesive layer 4 and an inner heat-welding resin layer 5, wherein the material of the outer base resin layer 1 comprises a mixed resin of nylon 6 and nylon 66, wherein the ratio of nylon 6 to nylon 66 in the mixed resin is 100:50, and the dynamic thermomechanical analysis spectrum of the mixed resin has a first characteristic peak in the range of 80°C to 100°C, with a peak height of <0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of <0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of <0.15.

[0057] Example 4

[0058] The present embodiment provides a gold-plastic composite film for battery outer packaging, wherein the structure of the gold-plastic composite film comprises, from outside to inside, an outer base resin layer 1, an outer adhesive layer 2, an intermediate metal layer 3, an inner adhesive layer 4 and an inner heat-welding resin layer 5, wherein the material of the outer base resin layer 1 comprises a mixed resin of nylon 6 and nylon 66, wherein the ratio of nylon 6 to nylon 66 in the mixed resin is 50:100, and the dynamic thermomechanical analysis spectrum of the mixed resin has a first characteristic peak in the range of 80°C to 100°C, with a peak height of <0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of <0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of <0.15.

[0059] Comparative Example 1

[0060] This comparative example provides a metal-plastic composite film for battery outer packaging, wherein the structure of the metal-plastic composite film includes, from outside to inside: an outer substrate resin layer 1, an outer adhesive layer 2, an intermediate metal layer 3, an inner adhesive layer 4 and an inner heat-welding resin layer 5, wherein the material of the outer substrate resin layer 1 comprises Polyester compounds, specifically polyethylene terephthalate, the dynamic thermomechanical analysis spectrum of the polyethylene terephthalate has a first characteristic peak in the range of 80°C to 100°C, with a peak height of >0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of >0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of >0.15.

[0061] Comparative Example 2

[0062] The present comparative example provides a metal-plastic composite film for battery outer packaging, wherein the structure of the metal-plastic composite film comprises, from outside to inside, an outer substrate resin layer 1, an outer adhesive layer 2, an intermediate metal layer 3, an inner adhesive layer 4 and an inner heat-welding resin layer 5, wherein the material of the outer substrate resin layer 1 comprises a mixed resin of polyethylene terephthalate and nylon 6, wherein the ratio of polyethylene terephthalate to nylon 6 in the mixed resin is 100:50, and the dynamic thermomechanical analysis spectrum of the mixed resin has a first characteristic peak in the range of 80°C to 100°C, with a peak height of <0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of >0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of >0.15.

[0063] Comparative Example 3

[0064] The present comparative example provides a metal-plastic composite film for battery outer packaging, wherein the structure of the metal-plastic composite film comprises, from outside to inside, an outer substrate resin layer 1, an outer adhesive layer 2, an intermediate metal layer 3, an inner adhesive layer 4 and an inner heat-welding resin layer 5, wherein the material of the outer substrate resin layer 1 comprises a mixed resin of polyethylene terephthalate and nylon 6, wherein the ratio of polyethylene terephthalate to nylon 6 in the mixed resin is 50:100, and the dynamic thermomechanical analysis spectrum of the mixed resin has a first characteristic peak in the range of 80°C to 100°C, with a peak height of >0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of <0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of >0.15.

[0065] For the convenience of comparison, the temperatures at which characteristic peaks appear and the corresponding peak heights in the dynamic thermomechanical analysis spectra of the resin materials of the outer substrate resin layer 1 described in Examples 1-4 and Comparative Examples 1-3 are listed in Table 1.

[0066] Table 1

[0067]

[0068] Test Case

[0069] The punching depth limit of the gold-plastic composite film for battery outer packaging provided in the examples and comparative examples was tested, and the test method was as follows:

[0070] (1) Drawing depth limit test:

[0071] Use the molding machine for testing, and the molding machine parameters are set as follows:

[0072] Shell size: 57mm*98mm

[0073] R angle: 1.5

[0074] Pressure: 0.4Mpa

[0075] Boost time: 0.1s / 1s

[0076] Core dwell time: 1.5s

[0077] The gold-plastic composite films for battery outer packaging provided in Examples 1-4 and Comparative Examples 1-3 were tested according to the above-mentioned drawing depth limit test method. The test results are shown in Table 2.

[0078] Table 2

[0079]

[0080]

[0081] The test results of Comparative Example 1 show that: when the material of the outer substrate resin layer 1 is a polyester compound, specifically polyethylene terephthalate, the dynamic thermomechanical analysis spectrum of the polyethylene terephthalate has a first characteristic peak in the range of 80°C to 100°C, with a peak height of >0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of >0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of >0.15. At this time, the gold-plastic composite film has a lower drawing depth limit under the condition of a pressurization time of 1s, and a lower drawing depth limit under the condition of a pressurization time of 0.1s.

[0082] The test results of Comparative Example 2 show that when the material of the outer substrate resin layer 1 is a mixed resin of polyethylene terephthalate and nylon 6 and the ratio of polyethylene terephthalate to nylon 6 in the mixed resin is (1-100):1, the dynamic thermomechanical analysis spectrum of the mixed resin has a first characteristic peak in the range of 80°C to 100°C, with a peak height of <0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of >0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of >0.15. At this time, the gold-plastic composite film has a lower depth limit under the condition of a pressurization time of 1s, and a lower depth limit under the condition of a pressurization time of 0.1s.

[0083] The test results of Comparative Example 3 show that when the material of the outer substrate resin layer 1 is a mixed resin of polyethylene terephthalate and nylon 6 and the ratio of polyethylene terephthalate to nylon 6 in the mixed resin is 1:(1-100), the dynamic thermomechanical analysis spectrum of the mixed resin has a first characteristic peak in the range of 80°C to 100°C, with a peak height of >0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of <0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of >0.15. At this time, the gold-plastic composite film has a lower drawing depth limit under the condition of a pressurization time of 1s, and a lower drawing depth limit under the condition of a pressurization time of 0.1s.

[0084] The test results of Examples 1-4 show that when the material of the outer substrate resin layer 1 is polyamide or its copolymer, the dynamic thermomechanical analysis spectrum of the mixed resin has a first characteristic peak in the range of 80°C to 100°C, with a peak height of <0.2; a second characteristic peak in the range of 20°C to 40°C, with a peak height of <0.2; and a third characteristic peak in the range of -60°C to -80°C, with a peak height of <0.15. At this time, the gold-plastic composite film exhibits excellent molding ability when the pressurization time is 0.1s and 1s.

[0085] It can be seen from the data of Examples 1-4 that the gold-plastic composite film for battery outer packaging provided by the present invention exhibits excellent molding ability when the pressurization time is 0.1s and 1s, effectively overcoming the limitations of the prior art on high punching depth (especially punching depth at high speed) of soft-pack lithium batteries, and has high industrial utilization value.

[0086] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0087] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A gold-plastic composite film for battery outer packaging, characterized in that: The metal-plastic composite film for battery outer packaging comprises an outer base resin layer, an intermediate metal layer, an inner adhesive layer and an inner heat-melting resin layer which are stacked in sequence; The outer substrate resin layer comprises a resin; the dynamic thermomechanical analysis spectrum of the resin has a first characteristic peak in the range of 60°C to 120°C, a second characteristic peak in the range of 0°C to 50°C, and a third characteristic peak in the range of -30°C to -90°C; The peak height of the first characteristic peak is <0.5, the peak height of the second characteristic peak is <0.2, and the peak height of the third characteristic peak is <0.

2.

2. The gold-plastic composite film for battery outer packaging according to claim 1, characterized in that: The dynamic thermomechanical analysis spectrum of the resin has a first characteristic peak in the range of 80°C to 100°C.

3. The gold-plastic composite film for battery outer packaging according to claim 1, characterized in that: The peak height of the first characteristic peak is less than 0.3, preferably less than 0.

2.

4. The gold-plastic composite film for battery outer packaging according to claim 1, characterized in that: The dynamic thermomechanical analysis spectrum of the resin has a second characteristic peak in the range of 20°C to 40°C.

5. The gold-plastic composite film for battery outer packaging according to claim 1, characterized in that: The dynamic thermomechanical analysis spectrum of the resin has a third characteristic peak in the range of -60°C to -80°C.

6. The gold-plastic composite film for battery outer packaging according to claim 1, characterized in that: The peak height of the third characteristic peak is less than 0.

15.

7. The gold-plastic composite film for battery outer packaging according to claim 1, characterized in that: The resin includes polyamide, and the polyamide includes aliphatic polyamide; Optionally, the aliphatic polyamide includes at least one of nylon 6, nylon 66, nylon 610, nylon 12, and nylon 46.

8. The gold-plastic composite film for battery outer packaging according to claim 7, characterized in that: The resin includes a copolymer of nylon 6 and nylon 66.

9. The gold-plastic composite film for battery outer packaging according to claim 8, characterized in that: The ratio of nylon 6 to nylon 66 in the copolymer of nylon 6 and nylon 66 is (100-1):(1-100).

10. A secondary battery, characterized in that: The secondary battery comprises the gold-plastic composite film for battery outer packaging according to any one of claims 1 to 9.

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