Metallized polypropylene reticular safety film

Abstract

The invention discloses a metalized polypropylene reticular safety film, and belongs to the field of capacitors. A metalized polypropylene net-shaped safety film comprises a base film and further comprises a plating layer structure arranged on the base film, the plating layer structure is sequentially provided with a thickening area, a transition area and a movable area in the length direction of the base film, the thickening area and the transition area are each of an aluminum-base-zinc thickening layer structure, and the movable area is of an aluminum layer structure; the marginal area is arranged in the marginal area of the plating layer structure; the protruding section is located at the starting end of the thickening area; wherein the plurality of rhombic unit structures of the plating layer structure are distributed in a continuous net shape; electric field concentration can be avoided, so that the direct-current breakdown voltage of the film is improved, the stable working requirement in a high-voltage environment is met, the problem that high-voltage breakdown is prone to occurring in the background technology is solved, meanwhile, the overall performance of the base film is improved, the service life of the base film is prolonged, the base film is prevented from being affected by oxidation and other factors, and the stability and reliability of the base film are guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of capacitors, in particular to a metalized polypropylene mesh safety film. BACKGROUND

[0002] In the battery management system of new energy vehicles, the metalized polypropylene mesh safety film is used for capacitors to ensure stable transmission and storage of power, which is crucial for the safe operation and performance improvement of new energy vehicles. In the converter of wind power generation, it also plays an indispensable role, which can effectively improve the power conversion efficiency and equipment stability.

[0003] The existing metalized polypropylene film has a low DC breakdown voltage of part of the base film, which cannot meet the use requirements in a high voltage environment. When facing a higher voltage, breakdown phenomenon is easy to occur, resulting in equipment failure and affecting the normal operation of the system. For example, some traditional metalized polypropylene films are difficult to work stably under a voltage of more than 1000V.DC. The plating layer design is not reasonable, and the common plating layer sheet resistance cannot meet the differentiated performance requirements in different areas. The same sheet resistance is used in the transition area and the active area, which makes it difficult to effectively balance the current distribution in different areas during current transmission, resulting in local overheating or overvoltage, reducing the overall performance and service life of the film. The full-paving method of the plating layer makes the edge of the base film vulnerable to oxidation and other factors, reducing the stability and reliability of the film. Moreover, it cannot effectively disperse the local electric field, resulting in local electric field concentration in a high voltage environment, which is easy to cause breakdown and other problems. In view of the above, the present application is proposed. SUMMARY

[0004] The purpose of the present application is to solve the problems in the prior art and provide a metalized polypropylene mesh safety film.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: A metalized polypropylene mesh safety film, comprising a base film, further comprising: A plating layer structure is arranged on the base film, the plating layer structure is sequentially provided with a thickening area, a transition area and an active area along the length direction of the base film, the thickening area and the transition area adopt an aluminum bottom zinc thickening layer structure, and the active area adopts an aluminum layer structure; A leftover edge area is arranged at the edge area of the plating layer structure; A protruding section is located at the starting end of the thickening area; Among them, the plurality of diamond cell structures of the plating layer structure are continuously distributed in a mesh shape.

[0006] Preferably, the thickness of the plating layer structure is characterized by the sheet resistance, wherein the thickened area has a sheet resistance I, the transition area has a sheet resistance II, and the active area has a sheet resistance III, and the sheet resistance I < sheet resistance II < sheet resistance III.

[0007] Further, the sheet resistance I is in the range of 1-10 Ω / □. The sheet resistance II is in the range of 3-15 Ω / □. The sheet resistance III is in the range of (20-30) ± (20-30) × 20% Ω / □.

[0008] Preferably, the total size of the base film in the length direction is A, the length of the thickened area in the plating layer structure is F, and the length of the transition area in the plating layer structure is G. Wherein, F + G ≤ A × 30%.

[0009] Further, the axial length of the active area is B + C + D, the size of the edge retention area in the thickness direction is E, and the total size A of the base film in the length direction satisfies: A = F + G + B + C + D + E.

[0010] Further, in the diamond cell structure of the plating layer structure, the line width of the plating layer structure is W, the short diagonal length of the diamond cell structure is H, and the long diagonal length of the diamond cell structure is I, and the line width W of the plating layer structure and the long diagonal length I and the short diagonal length H satisfy: I ≥ 20 × W and H ≥ 10 × W.

[0011] Further, all the diamond cell structures are periodically arranged along the length direction and the width direction of the base film, and the distance between the corresponding vertices of adjacent diamond cell structures is the plating layer repetition period F + G, wherein F + G ≥ 30 × W.

[0012] Preferably, in the aluminum bottom zinc thickened layer structure, the mass ratio of zinc to aluminum is 3-5:1-3.

[0013] Preferably, each of the diamond cell structures is formed by four metal conductive strips, forming a continuous and uninterrupted mesh conductive path, and adjacent diamond cell structures share a conductive strip.

[0014] Preferably, the transition area is a transition structure with gradually changing thickness of the aluminum bottom zinc thickened layer structure, and the edge retention area is a non-plating layer area at the edge of the plating layer structure.

[0015] Compared with the prior art, the present application provides a metalized polypropylene mesh safety film, which has the following beneficial effects: 1. The metalized polypropylene mesh safety film can realize multi-dimensional optimization in terms of conductive performance, mechanical strength, energy storage efficiency, oxidation resistance, processing adaptability, etc. by partitioning the plating layer structure 2, using different material layers, and combining the diamond mesh distribution, which not only guarantees the safety and reliability of the metalized film, but also improves the energy storage and service life in scenarios such as film capacitors.

[0016] 2. The metalized polypropylene mesh safety film can effectively disperse local electric field by using diamond cell structure, avoid electric field concentration, and the differential design of square resistance I, square resistance II, square resistance III combined with mesh cell structure can improve the direct current breakdown voltage under high voltage environment through the cooperation of resistance and structure, meet the stable working demand of high voltage scene, reduce the equipment failure caused by breakdown, and the gradient square resistance can balance the current distribution of different areas to avoid current concentration in a certain area.

[0017] 3. The metalized polypropylene mesh safety film, surrounded by four metal conductive strips and shared by adjacent cells, forms a continuous and uninterrupted mesh conductive path, maximizing the effective area of the conductive area and improving the current transmission efficiency. The diamond structure can disperse local current density and avoid local overheating. The mesh structure can effectively disperse local electric field and avoid electric field concentration, thereby improving the direct current breakdown voltage of the film and meeting the stable working demand under high voltage environment. The continuous mesh conductive strip design can realize self-healing by local conductive strip melting when overcurrent occurs, prevent fault propagation, and improve the safety and reliability of the film.

[0018] The parts not involved in the device are the same as or can be realized by the existing technology. The present application can avoid electric field concentration, thereby improving the direct current breakdown voltage of the film and meeting the stable working demand under high voltage environment. It solves the problem of high voltage easy breakdown in the background technology, improves the overall performance and service life of the base film, avoids the influence of oxidation and other factors, and guarantees the stability and reliability of the base film. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 A cross-sectional view of a metalized polypropylene mesh safety film according to the present application is shown. Fig. 2 A top view of a metalized polypropylene mesh safety film according to the present application is shown.

[0020] In the figure: 1, base film; 2, plating layer structure; 201, convex section; 202, thickened area; 203, transition area; 204, active area; 205, edge retention area. DETAILED DESCRIPTION

[0021] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application.

[0022] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0023] Embodiment one: Referring to Figs. 1-2 A metalized polypropylene mesh security film includes a base film 1, and further includes a plated layer structure 2 arranged on the base film 1, the plated layer structure 2 is sequentially provided with a thickening area 202, a transition area 203 and a movable area 204 along the length direction of the base film 1, the thickening area 202 and the transition area 203 adopt an aluminum bottom zinc thickening layer structure, and the movable area 204 adopts an aluminum layer structure; a leftover area 205 is further arranged at the edge area of the plated layer structure 2; a protruding section 201 is located at the starting end of the thickening area 202; wherein a plurality of diamond-shaped unit structures of the plated layer structure 2 are in a continuous mesh distribution.

[0024] In the embodiment, by partitioning the plated layer structure 2, using different material layers and combining the diamond mesh distribution, multi-dimensional optimization can be achieved in terms of conductive performance, mechanical strength, energy storage efficiency, oxidation resistance, processing adaptability and the like, which not only guarantees the safety and reliability of the metalized film, but also improves the energy storage and service life of the metalized film in scenarios such as film capacitors. Specifically, the protruding section 201 is located at the starting end of the thickening area 202, which is a thickness mutation structure of the aluminum bottom zinc thickening layer, and its role is to strengthen the conductive performance of the electrode lead-out end, improve the current carrying capacity by local thickening, and at the same time enhance the bonding force between the plated layer structure 2 and the base film 1 to avoid the plated layer from falling off during welding or winding; in addition, it can also optimize the current distribution and reduce the risk of local heating; the thickening area 202 adopts an aluminum bottom zinc thickening composite structure, the thickening design of the zinc layer can significantly reduce the square resistance and guarantee the low resistance conductive characteristics, and the aluminum bottom as the base improves the bonding stability of the plated layer structure 2 and the base film 1; the overall structure provides sufficient structural redundancy for electrode lead-out, welding and other processes, and is compatible with the processing accuracy of different equipment.

[0025] The transition zone 203 is a thickness transition area from the thickening zone 202 to the active zone 204, which functions to achieve a smooth transition of the thickness of the plating layer structure 2, avoid stress concentration and film body cracking caused by sudden thickness changes, and optimize the transmission process of the current from the thickening zone 202 to the active zone 204 through the gradual change of the resistance, thereby reducing energy loss. The active zone 204 is the core energy storage area of the film body, which can ensure sufficient energy storage density and can also prevent fault expansion and improve safety and reliability through self-healing effect, i.e., local insulation after the plating layer is partially fused. The diamond-shaped net-like distribution further increases the effective area of the conductive zone and optimizes the energy storage efficiency.

[0026] The edge retention zone 205 is located at the edge of the plating layer structure 2 and is an insulating area without plating layer or with thin plating layer, which functions to ensure the processing compatibility of the film body edge, avoid short circuit of the plating layer edge during winding, improve the insulation stability of the film body, prevent edge leakage, and adapt to the insulation requirements of capacitors and other scenarios.

[0027] Embodiment Two: Refer to Embodiment One Figs. 1-2 Further, the thickness of the plating layer structure 2 is characterized by sheet resistance, wherein the thickening zone 202 has sheet resistance I, the transition zone 203 has sheet resistance II, and the active zone 204 has sheet resistance III, and sheet resistance I < sheet resistance II < sheet resistance III.

[0028] The value range of sheet resistance I is 1-10 Ω / □. The value range of sheet resistance II is 3-15 Ω / □. The value range of sheet resistance III is (20-30) ± (20-30) x 20% Ω / □.

[0029] Specifically, in this application, the diamond-shaped unit structure can effectively disperse the local electric field and avoid electric field concentration. Moreover, the differential design of sheet resistance I, sheet resistance II, and sheet resistance III in combination with the net-like unit structure can improve the DC breakdown voltage in a high-voltage environment through the cooperation of resistance and structure, meet the stable working requirements of high-voltage scenarios, and reduce equipment failure caused by breakdown.

[0030] Sheet resistance I of the thickening zone 202 is set to 1-10 Ω / □, sheet resistance II of the transition zone 203 is set to 3-15 Ω / □, and sheet resistance III of the active zone 204 is set to (20-30) ± (20-30) x 20% Ω / □, forming a gradient sheet resistance. At the same time, the raised section 201 is provided to strengthen the current lead-out. The gradient sheet resistance can balance the current distribution in different areas and avoid current concentration in a certain area. The raised section 201 optimizes the conductive performance of the current lead-out end, further prevents local overheating and overvoltage, and thus improves the overall performance and service life of the film.

[0031] Example 3: Reference Figs. 1-2 The metalized polypropylene mesh security film is substantially the same as that of Example 1, and further, the total size of the base film 1 in the length direction is A, the length of the thickened area 202 in the coating structure 2 is F, and the length of the transition area 203 in the coating structure 2 is G. Wherein, F+G≤A×30%.

[0032] In this application, the size of F+G is 6mm, which is less than 30% of the total size A of the base film 1 in the length direction, the total size A of the base film 1 in the length direction is 25mm, and the length ratio of the length F of the thickened area 202 and the length G of the transition area 203 ensures the smooth transition of the coating structure 2, avoiding stress concentration or electrical performance fluctuations caused by sudden changes in the thickness of the coating structure 2.

[0033] The axial length of the active area 204 is B+C+D, the size of the edge area 205 in the thickness direction is E, and the total size A of the base film 1 in the length direction satisfies: A=F+G+B+C+D+E.

[0034] In this application, the total size A of the base film 1 in the length direction is 25mm, the size of F+G is 6mm, the size of the edge area 205 in the thickness direction E is 1.3±0.15mm, and the axial length B+C+D of the active area 204 is 17.7mm.

[0035] In the diamond cell structure of the coating structure 2, the line width of the coating structure 2 is W, the short diagonal length of the diamond cell structure is H, the long diagonal length of the diamond cell structure is I, and the line width W of the coating structure 2 and the long diagonal length I and the short diagonal length H satisfy: I≥20×W and H≥10×W.

[0036] Wherein, the line width W of the coating structure 2 is 0.15mm, the short diagonal length H of the diamond cell structure is 2mm, and the long diagonal length I of the diamond cell structure is 4mm; satisfying the above formula can ensure the structural strength of the conductive strip and the reasonable proportion of the meshed hollow area.

[0037] All the diamond cell structures are periodically arranged along the length and width directions of the base film 1, and the distance between the corresponding vertices of adjacent diamond cell structures is the coating repeat period F+G, wherein F+G≥30×W, i.e. 6mm≥30mm×0.15mm, to ensure the stability and electrical continuity of the mesh structure.

[0038] In the aluminum bottom zinc thickened layer structure, the mass ratio of zinc to aluminum is 3-5:1-3.

[0039] The proportion can significantly reduce the square resistance of the plating layer structure 2, maintain the square resistance I of the thickened area 202 in a low resistance range of 1-10 Ω / □, improve the current transmission efficiency, meet the stable transmission demand of large current in a high voltage scene, ensure the combination stability of the plating layer structure 2 and the base film 1 by taking aluminum as the base, enhance the wear resistance and deformation resistance of the plating layer structure 2 while improving the conductivity, avoid the peeling of the plating layer in the welding and winding process, and prolong the service life of the film body; and the mass ratio interval not only takes into account the low resistance characteristics of zinc and the structural stability of aluminum, but also meets the precision requirements of the industrial evaporation process, so that precise proportioning can be realized through conventional vacuum evaporation equipment; meanwhile, the material costs of zinc and aluminum are balanced under the premise of meeting the performance requirements, and good economic efficiency is achieved.

[0040] Each rhombic unit junction is formed by four metal conductive strips, forming a continuous and uninterrupted mesh conductive path, and adjacent rhombic unit structures share a conductive strip.

[0041] The transition area 203 is a transition structure with gradually changing thickness of the aluminum base zinc thickening layer structure, and the edge area 205 is a non-plating layer area at the edge of the plating layer structure 2.

[0042] In this embodiment, the four metal conductive strips are enclosed and adjacent units share the conductive strip, forming a continuous and uninterrupted mesh conductive path, maximizing the effective area of the conductive area and improving the current transmission efficiency, while the rhombic structure can disperse the local current density and avoid local overheating; the mesh structure can effectively disperse the local electric field and avoid electric field concentration, thereby improving the direct current breakdown voltage of the film and meeting the stable working demand in a high voltage environment, solving the problem of easy breakdown in a high voltage environment in the background art, and the continuous mesh conductive strip design can realize self-healing through local conductive strip melting when overcurrent occurs, preventing fault propagation and improving the safety and reliability of the film.

[0043] The thickness gradually changing design of the aluminum base zinc thickening layer structure can realize smooth transition of the plating layer from the thickened area 202 to the active area 204, avoid stress concentration and film cracking caused by sudden thickness change, and at the same time, the resistance also realizes smooth transition with the thickness gradually changing, optimizing the current transmission process from the thickened area 202 to the active area 204, reducing energy loss, and solving the problems of current distribution imbalance and local overheating and overvoltage.

[0044] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A metallized polypropylene net-like security film comprising a base film (1), characterized in that, Also include: The plating structure (2) provided on the base film (1), the plating structure (2) is sequentially provided with thickening area (202), transition area (203) and activity area (204) along the length direction of base film (1), the thickening area (202) and transition area (203) adopt aluminum bottom zinc thickening layer structure, the activity area (204) adopts aluminum layer structure; The edge area (205) is provided in the edge area of plating structure (2); The convex section (201) is located in the starting end of thickening area (202); Wherein, the plurality of diamond cell structure of the plating structure (2) is continuous net-like distribution.

2. The metallized polypropylene webbing security film of claim 1, wherein, The thickness of the plating structure (2) is characterized by sheet resistance, wherein the thickening area (202) has sheet resistance I, the transition area (203) has sheet resistance II, the activity area (204) has sheet resistance III, and the sheet resistance I < sheet resistance II < sheet resistance III.

3. The metallized polypropylene webbing security film of claim 2, wherein, The sheet resistance I is in the range of 1-10 Ω / □; The sheet resistance II is in the range of 3-15 Ω / □; The sheet resistance III is in the range of (20-30) ± (20-30) × 20% Ω / □.

4. The metallized polypropylene webbing security film of claim 1, wherein, The total size of the base film (1) in the length direction is A, the length of the thickening area (202) in the plating structure (2) is F, and the length of the transition area (203) in the plating structure (2) is G; Wherein, F+G≤A×30%.

5. The metallized polypropylene webbing security film of claim 4, wherein, The axial length of the activity area (204) is B+C+D, the size of the edge area (205) in the thickness direction is E, and the total size A of the base film 1 in the length direction satisfies: A=F+G+B+C+D+E.

6. The metallized polypropylene webbing security film of claim 5, wherein, In the diamond cell structure of the plating structure (2), the line width of the plating structure (2) is W, the short diagonal length of the diamond cell structure is H, and the long diagonal length of the diamond cell structure is I, the line width W of the plating structure (2) and the long diagonal length I, the short diagonal length H satisfy: I≥20×W and H≥10×W.

7. The metallized polypropylene webbing security film of claim 6, wherein, All the diamond cell structures are periodically arranged along the length direction and width direction of the base film (1), and the distance between the corresponding vertices of adjacent diamond cell structures is the plating repeat period F+G, wherein F+G≥30×W.

8. The metallized polypropylene webbing security film of claim 1, wherein, In the aluminum bottom zinc thickening layer structure, the mass ratio of zinc to aluminum is 3-5:1-3.

9. The metallized polypropylene webbing security film of claim 1, wherein, Each of the diamond cell structures is formed by four metal conductive strips, forming a continuous and uninterrupted net-like conductive path, and adjacent diamond cell structures share a conductive strip.

10. The metallized polypropylene webbing security film of claim 1, wherein, The transition area (203) is a transition structure with gradually changing thickness of the aluminum bottom zinc thickening layer structure, and the edge area (205) is a non-plating layer area of the edge of the plating structure (2).

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