A fireproof heat-insulating composite film and preparation method thereof

Abstract

The present invention discloses a fireproof heat-insulating composite film and a preparation method thereof, comprising a heat-conducting substrate layer, comprising a first surface and a second surface arranged oppositely, the first surface being provided with a plurality of receiving grooves, the receiving grooves being filled with a heat-expanding filling layer; and a fusible connecting layer being arranged in affixed to the first surface. During operation, the fireproof heat-insulating composite film is installed at a preset working position, and the second surface of the heat-conducting substrate layer is used as a contact surface for isolating an abnormal temperature rise area; when abnormal temperature rise does not occur, the heat-conducting substrate layer and the fusible connecting layer are in affixed with each other, heat conduction is performed, and a heat-conducting effect is played; when abnormal temperature rise occurs, the fusible connecting layer is melted by heat, and the heat-expanding filling layer is expanded by heat and squeezed out of the receiving groove, expanding to the position where the original fusible connecting layer is located, and the structural gap of the expanded heat-expanding filling layer is larger, which plays a role of heat insulation, and prevents the heat of the abnormal temperature rise area from being conducted to other areas, thereby improving safety.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a fireproof and heat-insulating composite film and a preparation method thereof. Background Art

[0002] In the application scenario of the isolation material between lithium battery cells, the activity of the lithium battery will be greatly reduced under low temperature conditions. Therefore, in order to maintain a high battery activity under low temperature conditions, the lithium battery needs to be heated.

[0003] In the battery pack of the prior art, heat conducting plates are arranged between the battery cells to facilitate heat dissipation. The disadvantage of this method is that the traditional heat conducting plates only have the function of conducting heat. When a single working battery cell thermally runs away and generates high temperature, the surrounding battery cells will thermally run away and form a chain reaction, causing a safety accident in the battery pack. Summary of the invention

[0004] The purpose of the present invention is to provide a fireproof and heat-insulating composite film and a preparation method thereof, so as to solve the technical problem that the traditional heat-conducting sheet cannot control the high-temperature transfer and causes safety accidents.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A fireproof and heat-insulating composite film, comprising:

[0007] The heat-conducting substrate layer comprises a first surface and a second surface arranged opposite to each other, wherein the first surface is provided with a plurality of receiving grooves, and the receiving grooves are filled with a heat expansion filling layer;

[0008] A fusible connection layer is disposed in contact with the first surface;

[0009] When the fusible connection layer is heated and melted, the heat-expandable filling layer is heated and expanded and extends into the fusible connection layer.

[0010] Optionally, the accommodating grooves are arranged in an array on the first surface.

[0011] Optionally, along the direction from the first surface to the second surface, the cross-sectional area of ​​the accommodating groove gradually decreases.

[0012] Optionally, the fireproof and heat-insulating composite film further comprises a heat-conductive surface layer, and the heat-conductive surface layer is connected to a surface of the fusible connecting layer away from the heat-conductive substrate layer.

[0013] Optionally, the heat-conductive surface layer and the heat-conductive substrate layer are heat-conductive layers of metal materials respectively.

[0014] Optionally, the fusible connection layer is a heat-meltable alloy welding layer.

[0015] Optionally, the thermal expansion filling layer is any one of an expandable fire retardant coating layer or an expandable graphite layer.

[0016] On the other hand, the present invention also provides a method for preparing a fireproof and heat-insulating composite film, which is used to prepare the fireproof and heat-insulating composite film as described above, comprising:

[0017] Providing a heat-conducting substrate layer, and processing a plurality of accommodating grooves on a first surface of the heat-conducting substrate layer;

[0018] Filling a thermal expansion filling layer in the containing groove;

[0019] A fusible connecting layer is provided and welded to the first surface to obtain a fireproof and heat-insulating composite film.

[0020] Optionally, providing a fusible connecting layer and welding the fusible connecting layer to the first surface to obtain a fireproof and heat-insulating composite film specifically includes:

[0021] Providing a fusible connecting layer, and attaching the fusible connecting layer to the first surface;

[0022] Providing a heat-conducting surface layer, and attaching the heat-conducting surface layer to a surface of the fusible connection layer away from the heat-conducting substrate layer;

[0023] A pressurizing device is used to press and heat the thermally conductive surface layer and the thermally conductive substrate layer respectively, and the fusible connecting layer is melted by the heat. The fusible connecting layer after heat melting is heat-melted and welded to the thermally conductive surface layer and the thermally conductive substrate layer respectively to obtain a fireproof and heat-insulating composite film.

[0024] Optionally, the step of providing a fusible connecting layer and welding the fusible connecting layer to the first surface to obtain a fireproof and heat-insulating composite film further includes:

[0025] The fireproof and heat-insulating composite film on the pressurizing device is cooled down, and when it is cooled to a preset temperature, the fireproof and heat-insulating composite film is removed.

[0026] Compared with the prior art, the present invention has the following beneficial effects: when working, the fireproof and heat-insulating composite film is installed at a preset working position, and the second surface of the thermally conductive substrate layer serves as a contact surface for isolating the abnormal temperature rise area; when abnormal temperature rise does not occur, the thermally conductive substrate layer and the fusible connecting layer fit together to conduct heat and play a heat-conducting role; when abnormal temperature rise occurs, the fusible connecting layer is melted by the heat, and the thermal expansion filling layer is expanded by the heat and squeezed out of the accommodating groove and expanded to the position where the original fusible connecting layer was located. The structural gap of the expanded thermal expansion filling layer is larger, which plays a heat-insulating role and prevents the heat from being conducted to other areas in the abnormal temperature rise area, thereby improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical contents disclosed by the present invention.

[0029] Figure 1 This is a schematic diagram of the structure of the fireproof and heat-insulating composite film.

[0030] Illustration: heat-conducting substrate layer 1 , receiving groove 11 , first surface 12 , second surface 13 , fusible connection layer 2 , thermal expansion filling layer 3 , heat-conducting surface layer 4 . DETAILED DESCRIPTION

[0031] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should be noted that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time.

[0033] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0034] Embodiment 1:

[0035] The present invention provides a fireproof and heat-insulating composite film, comprising:

[0036] The heat-conducting substrate layer 1 comprises a first surface 12 and a second surface 13 which are arranged opposite to each other. The first surface 12 is provided with a plurality of receiving grooves 11, and the receiving grooves 11 are filled with a heat-expanding filling layer 3;

[0037] The fusible connection layer 2 is disposed on the first surface 12;

[0038] When the fusible connection layer 2 is heated and melted, the thermal expansion filling layer 3 is heated and expanded and extends into the fusible connection layer 2 .

[0039] It is easy to understand that when the fusible link layer 2 is heated and melted, the partially melted fusible link layer 2 will separate from the first surface 12, and the heat-expandable filling layer 3 will expand outwards due to the heat and fill into the space where the unmelted fusible link layer 2 is located, and squeeze out the remaining fusible link layer 2;

[0040] Among them, the thermal expansion filling layer 3 after expansion has a heat insulation principle of expanding into a larger puffed structure due to heat. The puffed structure includes a plurality of microstructures with larger gaps, which are filled with more air, and can effectively isolate heat conduction and play a role of heat insulation.

[0041] It should be noted that when the fireproof and heat-insulating composite film undergoes structural changes when heated, the thickness of the thermal expansion filling layer 3 will become thicker. This process is an irreversible process. Therefore, after being triggered once, the fireproof and heat-insulating composite film needs to be replaced regularly.

[0042] The working principle of the present invention is as follows: when working, the fireproof and heat-insulating composite film is installed at a preset working position, and the second surface 13 of the heat-conducting substrate layer 1 is used as a contact surface to isolate the abnormal temperature rise area; when no abnormal temperature rise occurs, the heat-conducting substrate layer 1 and the fusible connecting layer 2 are in contact with each other to conduct heat and play a heat-conducting role; when abnormal temperature rise occurs, the fusible connecting layer 2 is melted by the heat, and the thermal expansion filling layer 3 is expanded by the heat and squeezed out of the accommodating groove 11, and expanded to the position where the original fusible connecting layer 2 was located. The structural gap of the expanded thermal expansion filling layer 3 is larger, which plays a heat-insulating role, preventing the heat from the abnormal temperature rise area from being conducted to other areas, thereby improving safety.

[0043] As a preferred solution of this embodiment, the receiving grooves 11 are arranged in an array on the first surface 12. The receiving grooves 11 are in the shape of pits, and a plurality of receiving grooves 11 arranged in an array are processed by etching;

[0044] To further illustrate, the cross-sectional area of ​​the receiving groove 11 gradually decreases along the direction from the first surface 12 to the second surface 13; that is, the receiving groove 11 is a trapezoidal groove, and the side wall of the receiving groove 11 is an inclined surface; on the one hand, the trapezoidal groove facilitates the filling of the thermal expansion filling layer 3; on the other hand, when the thermal expansion filling layer 3 in the receiving groove 11 expands due to heat, the guiding effect of the inclined surface facilitates the expansion of the thermal expansion filling layer 3 into the space where the fusible connecting layer 2 is located.

[0045] In this embodiment, the fireproof and heat-insulating composite film further comprises a heat-conducting surface layer 4 , which is connected to a surface of the fusible connecting layer 2 away from the heat-conducting substrate layer 1 .

[0046] Combination Figure 1 As shown, the thermally conductive surface layer 4 and the thermally conductive substrate layer 1 in this scheme are arranged at intervals, and a fusible connecting layer 2 is connected between the two; when working normally, the thermally conductive surface layer 4, the fusible connecting layer 2 and the thermally conductive substrate layer 1 are in a state of thermal conduction, which can play a role in heat conduction and heat dissipation; when applied to battery components, the fireproof and heat-insulating composite film can ensure the thermal conductivity between two adjacent batteries, play a role in heat dissipation, avoid heat accumulation, and improve the performance of the lithium battery pack.

[0047] To further illustrate, the heat-conducting surface layer 4 and the heat-conducting base material layer 1 are heat-conducting layers made of metal materials respectively.

[0048] It should be noted that the thermal conductive layer needs to have good thermal conductivity and be easy to etch (to facilitate processing of the accommodating groove 11); the thermal conductive layer can be made of pure metal or alloy, among which a copper-based alloy layer or an aluminum-based alloy layer is preferred.

[0049] As a preferred solution of this embodiment, the fusible connection layer 2 is a heat-melting alloy welding layer. The fusible connection layer 2 uses an alloy welding layer with a low melting point (heat-melting) between 60 and 200°C. The alloy welding layer can be made in the following ways:

[0050] 1. A eutectic low melting point alloy composed of a certain proportion of bismuth, cadmium, tin, lead, dysprosium, indium and other elements as the main components;

[0051] 2. Lead-free low melting point alloy;

[0052] 3. Bismuth-tin low melting point alloy;

[0053] Among them, methods 2 and 3 are environmentally friendly materials.

[0054] It should be noted that the fusible link layer 2 in the present embodiment adopts an alloy welding layer of one or more low-melting-point metal elements, and there are various proportions of the low-melting-point metal elements, thereby forming different fusible link layers 2;

[0055] Different types of fusible link layers 2 have different melting points. In actual operation, the type of alloy welding layer can be selected according to the required protective temperature.

[0056] In this embodiment, the thermal expansion filling layer 3 is any one of an expandable fire retardant coating layer or an expandable graphite layer.

[0057] It should be noted that the intumescent fire retardant coating layer includes special flame retardants, foaming agents, special resins, flexible fillers, refractory fibers, special emulsions, anti-settling agents and auxiliary materials;

[0058] The working principle of the intumescent fire retardant coating layer is as follows: when encountering high temperature, the foaming agent (one of the ingredients) generates gas during the heating process, and forms a porous carbon layer with pores that are tens of times thicker than the original coating in the polymer composition, realizing the expansion process; the porous carbon layer has better thermal insulation performance, which can block the heat transfer of external heat sources to the substrate, forming an insulating barrier, and the expanded intumescent fire retardant coating layer plays a role in heat insulation;

[0059] Embodiment 2:

[0060] The present invention also provides a method for preparing a fireproof and heat-insulating composite film, which is used to prepare the fireproof and heat-insulating composite film as in Example 1, comprising:

[0061] A heat-conducting substrate layer 1 is provided, and a plurality of receiving grooves 11 are processed on a first surface 12 of the heat-conducting substrate layer 1; the processing method of the receiving grooves 11 can be washing or etching, and the preferred method is etching;

[0062] Fill the thermal expansion filling layer 3 in the receiving groove 11; when filling, fill inward from the opening surface of the receiving groove 11, and the thermal expansion filling layer 3 can be filled completely or a certain gap space can be reserved. The thermal expansion filling layer 3 will occupy a larger space position, and the amount of the thermal expansion filling layer 3 can be flexibly adjusted according to actual needs;

[0063] Providing a fusible connecting layer 2, and welding the fusible connecting layer 2 to the first surface 12 to obtain a fireproof and heat-insulating composite film;

[0064] The fireproof and heat-insulating composite film on the pressurizing device is cooled down, and when cooled to a preset temperature, the fireproof and heat-insulating composite film is removed; thus, a finished fireproof and heat-insulating composite film is obtained, which can be installed between two adjacent battery cells in a lithium battery pack when in use.

[0065] In this embodiment, a fusible connecting layer 2 is provided, and the fusible connecting layer 2 is welded to the first surface 12 to obtain a fireproof and heat-insulating composite film, which specifically includes:

[0066] Providing a fusible connection layer 2, and attaching the fusible connection layer 2 to the first surface 12;

[0067] Providing a heat-conducting surface layer 4, and attaching the heat-conducting surface layer 4 to a surface of the fusible connecting layer 2 away from the heat-conducting substrate layer 1;

[0068] A pressurizing device is used to press and heat the heat-conducting surface layer 4 and the heat-conducting substrate layer 1 respectively; the fusible connecting layer 2 is melted by the heat, and the fusible connecting layer 2 after heat melting is heat-melted and welded to the heat-conducting surface layer 4 and the heat-conducting substrate layer 1 respectively to obtain a fireproof and heat-insulating composite film.

[0069] It should be noted that the pressurizing device includes two pressing components that move relative to each other and are equipped with a heating

[0070] Components; when working, the bonded workpiece blank is placed between the two pressing components, the two pressing components are close to each other, and the fusible connecting layer 2 after hot melting is hot melt welded with the thermal conductive surface layer 4 and the thermal conductive substrate layer 1 respectively to form an integral fireproof and heat-insulating composite film; at this time, the temperature of the fireproof and heat-insulating composite film is relatively high, so it needs to be cooled.

[0071] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fireproof and heat-insulating composite film, characterized in that: include: The heat-conducting substrate layer comprises a first surface and a second surface arranged opposite to each other, wherein the first surface is provided with a plurality of receiving grooves, and the receiving grooves are filled with a heat expansion filling layer; A fusible connection layer is disposed in contact with the first surface; Wherein, when the fusible connection layer is heated and melted, the thermal expansion filling layer is thermally expanded and expanded into the fusible connection layer; Specifically, when the fusible connecting layer is heated and melted, the partially melted fusible connecting layer will separate from the first surface, and the heat-expandable filling layer will expand outwards under the heat and fill into the space where the unmelted fusible connecting layer is located, and squeeze out the remaining fusible connecting layer; It also includes a heat-conducting surface layer, the heat-conducting surface layer is connected to a surface of the fusible connecting layer away from the heat-conducting substrate layer; The heat-conducting surface layer and the heat-conducting base material layer are respectively heat-conducting layers of metal materials.

2. The fireproof and heat-insulating composite film according to claim 1, characterized in that: The containing grooves are arranged in an array on the first surface.

3. The fireproof and heat-insulating composite film according to claim 1, characterized in that: Along the direction from the first surface to the second surface, the cross-sectional area of ​​the accommodation groove gradually decreases.

4. The fireproof and heat-insulating composite film according to claim 1, characterized in that: The fusible connection layer is a heat-meltable alloy welding layer.

5. The fireproof and heat-insulating composite film according to claim 1, characterized in that: The thermal expansion filling layer is any one of an expandable fire retardant coating layer or an expandable graphite layer.

6. A method for preparing a fireproof and heat-insulating composite film, characterized in that: Used to prepare the fireproof and heat-insulating composite film according to any one of claims 1 to 5, comprising: Providing a heat-conducting substrate layer, and processing a plurality of accommodating grooves on a first surface of the heat-conducting substrate layer; Filling a thermal expansion filling layer in the containing groove; A fusible connecting layer is provided and welded to the first surface to obtain a fireproof and heat-insulating composite film.

7. The preparation method according to claim 6, characterized in that: The method of providing a fusible connecting layer and welding the fusible connecting layer to the first surface to obtain a fireproof and heat-insulating composite film specifically includes: Providing a fusible connecting layer, and attaching the fusible connecting layer to the first surface; Providing a heat-conducting surface layer, and attaching the heat-conducting surface layer to a surface of the fusible connection layer away from the heat-conducting substrate layer; A pressurizing device is used to press and heat the thermally conductive surface layer and the thermally conductive substrate layer respectively, and the fusible connecting layer is melted by the heat. The fusible connecting layer after heat melting is heat-melted and welded to the thermally conductive surface layer and the thermally conductive substrate layer respectively to obtain a fireproof and heat-insulating composite film.

8. The preparation method according to claim 6, characterized in that: The method further comprises: providing a fusible connecting layer, welding the fusible connecting layer to the first surface, and obtaining a fireproof and heat-insulating composite film; and then: The fireproof and heat-insulating composite film on the pressurizing device is cooled down, and when it is cooled to a preset temperature, the fireproof and heat-insulating composite film is removed.

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